| /* |
| * kernel/sched.c |
| * |
| * Kernel scheduler and related syscalls |
| * |
| * Copyright (C) 1991-2002 Linus Torvalds |
| * |
| * 1996-12-23 Modified by Dave Grothe to fix bugs in semaphores and |
| * make semaphores SMP safe |
| * 1998-11-19 Implemented schedule_timeout() and related stuff |
| * by Andrea Arcangeli |
| * 2002-01-04 New ultra-scalable O(1) scheduler by Ingo Molnar: |
| * hybrid priority-list and round-robin design with |
| * an array-switch method of distributing timeslices |
| * and per-CPU runqueues. Cleanups and useful suggestions |
| * by Davide Libenzi, preemptible kernel bits by Robert Love. |
| * 2003-09-03 Interactivity tuning by Con Kolivas. |
| * 2004-04-02 Scheduler domains code by Nick Piggin |
| * 2007-04-15 Work begun on replacing all interactivity tuning with a |
| * fair scheduling design by Con Kolivas. |
| * 2007-05-05 Load balancing (smp-nice) and other improvements |
| * by Peter Williams |
| * 2007-05-06 Interactivity improvements to CFS by Mike Galbraith |
| * 2007-07-01 Group scheduling enhancements by Srivatsa Vaddagiri |
| * 2007-11-29 RT balancing improvements by Steven Rostedt, Gregory Haskins, |
| * Thomas Gleixner, Mike Kravetz |
| */ |
| |
| #include <linux/mm.h> |
| #include <linux/module.h> |
| #include <linux/nmi.h> |
| #include <linux/init.h> |
| #include <linux/uaccess.h> |
| #include <linux/highmem.h> |
| #include <linux/smp_lock.h> |
| #include <asm/mmu_context.h> |
| #include <linux/interrupt.h> |
| #include <linux/capability.h> |
| #include <linux/completion.h> |
| #include <linux/kernel_stat.h> |
| #include <linux/debug_locks.h> |
| #include <linux/security.h> |
| #include <linux/notifier.h> |
| #include <linux/profile.h> |
| #include <linux/freezer.h> |
| #include <linux/vmalloc.h> |
| #include <linux/blkdev.h> |
| #include <linux/delay.h> |
| #include <linux/pid_namespace.h> |
| #include <linux/smp.h> |
| #include <linux/threads.h> |
| #include <linux/timer.h> |
| #include <linux/rcupdate.h> |
| #include <linux/cpu.h> |
| #include <linux/cpuset.h> |
| #include <linux/percpu.h> |
| #include <linux/kthread.h> |
| #include <linux/seq_file.h> |
| #include <linux/sysctl.h> |
| #include <linux/syscalls.h> |
| #include <linux/times.h> |
| #include <linux/tsacct_kern.h> |
| #include <linux/kprobes.h> |
| #include <linux/delayacct.h> |
| #include <linux/reciprocal_div.h> |
| #include <linux/unistd.h> |
| #include <linux/pagemap.h> |
| #include <linux/hrtimer.h> |
| #include <linux/tick.h> |
| #include <linux/bootmem.h> |
| #include <linux/debugfs.h> |
| #include <linux/ctype.h> |
| #include <linux/ftrace.h> |
| |
| #include <asm/tlb.h> |
| #include <asm/irq_regs.h> |
| |
| #include "sched_cpupri.h" |
| |
| /* |
| * Convert user-nice values [ -20 ... 0 ... 19 ] |
| * to static priority [ MAX_RT_PRIO..MAX_PRIO-1 ], |
| * and back. |
| */ |
| #define NICE_TO_PRIO(nice) (MAX_RT_PRIO + (nice) + 20) |
| #define PRIO_TO_NICE(prio) ((prio) - MAX_RT_PRIO - 20) |
| #define TASK_NICE(p) PRIO_TO_NICE((p)->static_prio) |
| |
| /* |
| * 'User priority' is the nice value converted to something we |
| * can work with better when scaling various scheduler parameters, |
| * it's a [ 0 ... 39 ] range. |
| */ |
| #define USER_PRIO(p) ((p)-MAX_RT_PRIO) |
| #define TASK_USER_PRIO(p) USER_PRIO((p)->static_prio) |
| #define MAX_USER_PRIO (USER_PRIO(MAX_PRIO)) |
| |
| /* |
| * Helpers for converting nanosecond timing to jiffy resolution |
| */ |
| #define NS_TO_JIFFIES(TIME) ((unsigned long)(TIME) / (NSEC_PER_SEC / HZ)) |
| |
| #define NICE_0_LOAD SCHED_LOAD_SCALE |
| #define NICE_0_SHIFT SCHED_LOAD_SHIFT |
| |
| /* |
| * These are the 'tuning knobs' of the scheduler: |
| * |
| * default timeslice is 100 msecs (used only for SCHED_RR tasks). |
| * Timeslices get refilled after they expire. |
| */ |
| #define DEF_TIMESLICE (100 * HZ / 1000) |
| |
| /* |
| * single value that denotes runtime == period, ie unlimited time. |
| */ |
| #define RUNTIME_INF ((u64)~0ULL) |
| |
| #ifdef CONFIG_SMP |
| /* |
| * Divide a load by a sched group cpu_power : (load / sg->__cpu_power) |
| * Since cpu_power is a 'constant', we can use a reciprocal divide. |
| */ |
| static inline u32 sg_div_cpu_power(const struct sched_group *sg, u32 load) |
| { |
| return reciprocal_divide(load, sg->reciprocal_cpu_power); |
| } |
| |
| /* |
| * Each time a sched group cpu_power is changed, |
| * we must compute its reciprocal value |
| */ |
| static inline void sg_inc_cpu_power(struct sched_group *sg, u32 val) |
| { |
| sg->__cpu_power += val; |
| sg->reciprocal_cpu_power = reciprocal_value(sg->__cpu_power); |
| } |
| #endif |
| |
| static inline int rt_policy(int policy) |
| { |
| if (unlikely(policy == SCHED_FIFO || policy == SCHED_RR)) |
| return 1; |
| return 0; |
| } |
| |
| static inline int task_has_rt_policy(struct task_struct *p) |
| { |
| return rt_policy(p->policy); |
| } |
| |
| /* |
| * This is the priority-queue data structure of the RT scheduling class: |
| */ |
| struct rt_prio_array { |
| DECLARE_BITMAP(bitmap, MAX_RT_PRIO+1); /* include 1 bit for delimiter */ |
| struct list_head queue[MAX_RT_PRIO]; |
| }; |
| |
| struct rt_bandwidth { |
| /* nests inside the rq lock: */ |
| spinlock_t rt_runtime_lock; |
| ktime_t rt_period; |
| u64 rt_runtime; |
| struct hrtimer rt_period_timer; |
| }; |
| |
| static struct rt_bandwidth def_rt_bandwidth; |
| |
| static int do_sched_rt_period_timer(struct rt_bandwidth *rt_b, int overrun); |
| |
| static enum hrtimer_restart sched_rt_period_timer(struct hrtimer *timer) |
| { |
| struct rt_bandwidth *rt_b = |
| container_of(timer, struct rt_bandwidth, rt_period_timer); |
| ktime_t now; |
| int overrun; |
| int idle = 0; |
| |
| for (;;) { |
| now = hrtimer_cb_get_time(timer); |
| overrun = hrtimer_forward(timer, now, rt_b->rt_period); |
| |
| if (!overrun) |
| break; |
| |
| idle = do_sched_rt_period_timer(rt_b, overrun); |
| } |
| |
| return idle ? HRTIMER_NORESTART : HRTIMER_RESTART; |
| } |
| |
| static |
| void init_rt_bandwidth(struct rt_bandwidth *rt_b, u64 period, u64 runtime) |
| { |
| rt_b->rt_period = ns_to_ktime(period); |
| rt_b->rt_runtime = runtime; |
| |
| spin_lock_init(&rt_b->rt_runtime_lock); |
| |
| hrtimer_init(&rt_b->rt_period_timer, |
| CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
| rt_b->rt_period_timer.function = sched_rt_period_timer; |
| rt_b->rt_period_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ; |
| } |
| |
| static void start_rt_bandwidth(struct rt_bandwidth *rt_b) |
| { |
| ktime_t now; |
| |
| if (rt_b->rt_runtime == RUNTIME_INF) |
| return; |
| |
| if (hrtimer_active(&rt_b->rt_period_timer)) |
| return; |
| |
| spin_lock(&rt_b->rt_runtime_lock); |
| for (;;) { |
| if (hrtimer_active(&rt_b->rt_period_timer)) |
| break; |
| |
| now = hrtimer_cb_get_time(&rt_b->rt_period_timer); |
| hrtimer_forward(&rt_b->rt_period_timer, now, rt_b->rt_period); |
| hrtimer_start(&rt_b->rt_period_timer, |
| rt_b->rt_period_timer.expires, |
| HRTIMER_MODE_ABS); |
| } |
| spin_unlock(&rt_b->rt_runtime_lock); |
| } |
| |
| #ifdef CONFIG_RT_GROUP_SCHED |
| static void destroy_rt_bandwidth(struct rt_bandwidth *rt_b) |
| { |
| hrtimer_cancel(&rt_b->rt_period_timer); |
| } |
| #endif |
| |
| /* |
| * sched_domains_mutex serializes calls to arch_init_sched_domains, |
| * detach_destroy_domains and partition_sched_domains. |
| */ |
| static DEFINE_MUTEX(sched_domains_mutex); |
| |
| #ifdef CONFIG_GROUP_SCHED |
| |
| #include <linux/cgroup.h> |
| |
| struct cfs_rq; |
| |
| static LIST_HEAD(task_groups); |
| |
| /* task group related information */ |
| struct task_group { |
| #ifdef CONFIG_CGROUP_SCHED |
| struct cgroup_subsys_state css; |
| #endif |
| |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| /* schedulable entities of this group on each cpu */ |
| struct sched_entity **se; |
| /* runqueue "owned" by this group on each cpu */ |
| struct cfs_rq **cfs_rq; |
| unsigned long shares; |
| #endif |
| |
| #ifdef CONFIG_RT_GROUP_SCHED |
| struct sched_rt_entity **rt_se; |
| struct rt_rq **rt_rq; |
| |
| struct rt_bandwidth rt_bandwidth; |
| #endif |
| |
| struct rcu_head rcu; |
| struct list_head list; |
| |
| struct task_group *parent; |
| struct list_head siblings; |
| struct list_head children; |
| }; |
| |
| #ifdef CONFIG_USER_SCHED |
| |
| /* |
| * Root task group. |
| * Every UID task group (including init_task_group aka UID-0) will |
| * be a child to this group. |
| */ |
| struct task_group root_task_group; |
| |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| /* Default task group's sched entity on each cpu */ |
| static DEFINE_PER_CPU(struct sched_entity, init_sched_entity); |
| /* Default task group's cfs_rq on each cpu */ |
| static DEFINE_PER_CPU(struct cfs_rq, init_cfs_rq) ____cacheline_aligned_in_smp; |
| #endif /* CONFIG_FAIR_GROUP_SCHED */ |
| |
| #ifdef CONFIG_RT_GROUP_SCHED |
| static DEFINE_PER_CPU(struct sched_rt_entity, init_sched_rt_entity); |
| static DEFINE_PER_CPU(struct rt_rq, init_rt_rq) ____cacheline_aligned_in_smp; |
| #endif /* CONFIG_RT_GROUP_SCHED */ |
| #else /* !CONFIG_FAIR_GROUP_SCHED */ |
| #define root_task_group init_task_group |
| #endif /* CONFIG_FAIR_GROUP_SCHED */ |
| |
| /* task_group_lock serializes add/remove of task groups and also changes to |
| * a task group's cpu shares. |
| */ |
| static DEFINE_SPINLOCK(task_group_lock); |
| |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| #ifdef CONFIG_USER_SCHED |
| # define INIT_TASK_GROUP_LOAD (2*NICE_0_LOAD) |
| #else /* !CONFIG_USER_SCHED */ |
| # define INIT_TASK_GROUP_LOAD NICE_0_LOAD |
| #endif /* CONFIG_USER_SCHED */ |
| |
| /* |
| * A weight of 0 or 1 can cause arithmetics problems. |
| * A weight of a cfs_rq is the sum of weights of which entities |
| * are queued on this cfs_rq, so a weight of a entity should not be |
| * too large, so as the shares value of a task group. |
| * (The default weight is 1024 - so there's no practical |
| * limitation from this.) |
| */ |
| #define MIN_SHARES 2 |
| #define MAX_SHARES (1UL << 18) |
| |
| static int init_task_group_load = INIT_TASK_GROUP_LOAD; |
| #endif |
| |
| /* Default task group. |
| * Every task in system belong to this group at bootup. |
| */ |
| struct task_group init_task_group; |
| |
| /* return group to which a task belongs */ |
| static inline struct task_group *task_group(struct task_struct *p) |
| { |
| struct task_group *tg; |
| |
| #ifdef CONFIG_USER_SCHED |
| tg = p->user->tg; |
| #elif defined(CONFIG_CGROUP_SCHED) |
| tg = container_of(task_subsys_state(p, cpu_cgroup_subsys_id), |
| struct task_group, css); |
| #else |
| tg = &init_task_group; |
| #endif |
| return tg; |
| } |
| |
| /* Change a task's cfs_rq and parent entity if it moves across CPUs/groups */ |
| static inline void set_task_rq(struct task_struct *p, unsigned int cpu) |
| { |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| p->se.cfs_rq = task_group(p)->cfs_rq[cpu]; |
| p->se.parent = task_group(p)->se[cpu]; |
| #endif |
| |
| #ifdef CONFIG_RT_GROUP_SCHED |
| p->rt.rt_rq = task_group(p)->rt_rq[cpu]; |
| p->rt.parent = task_group(p)->rt_se[cpu]; |
| #endif |
| } |
| |
| #else |
| |
| static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { } |
| static inline struct task_group *task_group(struct task_struct *p) |
| { |
| return NULL; |
| } |
| |
| #endif /* CONFIG_GROUP_SCHED */ |
| |
| /* CFS-related fields in a runqueue */ |
| struct cfs_rq { |
| struct load_weight load; |
| unsigned long nr_running; |
| |
| u64 exec_clock; |
| u64 min_vruntime; |
| u64 pair_start; |
| |
| struct rb_root tasks_timeline; |
| struct rb_node *rb_leftmost; |
| |
| struct list_head tasks; |
| struct list_head *balance_iterator; |
| |
| /* |
| * 'curr' points to currently running entity on this cfs_rq. |
| * It is set to NULL otherwise (i.e when none are currently running). |
| */ |
| struct sched_entity *curr, *next; |
| |
| unsigned long nr_spread_over; |
| |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| struct rq *rq; /* cpu runqueue to which this cfs_rq is attached */ |
| |
| /* |
| * leaf cfs_rqs are those that hold tasks (lowest schedulable entity in |
| * a hierarchy). Non-leaf lrqs hold other higher schedulable entities |
| * (like users, containers etc.) |
| * |
| * leaf_cfs_rq_list ties together list of leaf cfs_rq's in a cpu. This |
| * list is used during load balance. |
| */ |
| struct list_head leaf_cfs_rq_list; |
| struct task_group *tg; /* group that "owns" this runqueue */ |
| |
| #ifdef CONFIG_SMP |
| /* |
| * the part of load.weight contributed by tasks |
| */ |
| unsigned long task_weight; |
| |
| /* |
| * h_load = weight * f(tg) |
| * |
| * Where f(tg) is the recursive weight fraction assigned to |
| * this group. |
| */ |
| unsigned long h_load; |
| |
| /* |
| * this cpu's part of tg->shares |
| */ |
| unsigned long shares; |
| |
| /* |
| * load.weight at the time we set shares |
| */ |
| unsigned long rq_weight; |
| #endif |
| #endif |
| }; |
| |
| /* Real-Time classes' related field in a runqueue: */ |
| struct rt_rq { |
| struct rt_prio_array active; |
| unsigned long rt_nr_running; |
| #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED |
| int highest_prio; /* highest queued rt task prio */ |
| #endif |
| #ifdef CONFIG_SMP |
| unsigned long rt_nr_migratory; |
| int overloaded; |
| #endif |
| int rt_throttled; |
| u64 rt_time; |
| u64 rt_runtime; |
| /* Nests inside the rq lock: */ |
| spinlock_t rt_runtime_lock; |
| |
| #ifdef CONFIG_RT_GROUP_SCHED |
| unsigned long rt_nr_boosted; |
| |
| struct rq *rq; |
| struct list_head leaf_rt_rq_list; |
| struct task_group *tg; |
| struct sched_rt_entity *rt_se; |
| #endif |
| }; |
| |
| #ifdef CONFIG_SMP |
| |
| /* |
| * We add the notion of a root-domain which will be used to define per-domain |
| * variables. Each exclusive cpuset essentially defines an island domain by |
| * fully partitioning the member cpus from any other cpuset. Whenever a new |
| * exclusive cpuset is created, we also create and attach a new root-domain |
| * object. |
| * |
| */ |
| struct root_domain { |
| atomic_t refcount; |
| cpumask_t span; |
| cpumask_t online; |
| |
| /* |
| * The "RT overload" flag: it gets set if a CPU has more than |
| * one runnable RT task. |
| */ |
| cpumask_t rto_mask; |
| atomic_t rto_count; |
| #ifdef CONFIG_SMP |
| struct cpupri cpupri; |
| #endif |
| }; |
| |
| /* |
| * By default the system creates a single root-domain with all cpus as |
| * members (mimicking the global state we have today). |
| */ |
| static struct root_domain def_root_domain; |
| |
| #endif |
| |
| /* |
| * This is the main, per-CPU runqueue data structure. |
| * |
| * Locking rule: those places that want to lock multiple runqueues |
| * (such as the load balancing or the thread migration code), lock |
| * acquire operations must be ordered by ascending &runqueue. |
| */ |
| struct rq { |
| /* runqueue lock: */ |
| spinlock_t lock; |
| |
| /* |
| * nr_running and cpu_load should be in the same cacheline because |
| * remote CPUs use both these fields when doing load calculation. |
| */ |
| unsigned long nr_running; |
| #define CPU_LOAD_IDX_MAX 5 |
| unsigned long cpu_load[CPU_LOAD_IDX_MAX]; |
| unsigned char idle_at_tick; |
| #ifdef CONFIG_NO_HZ |
| unsigned long last_tick_seen; |
| unsigned char in_nohz_recently; |
| #endif |
| /* capture load from *all* tasks on this cpu: */ |
| struct load_weight load; |
| unsigned long nr_load_updates; |
| u64 nr_switches; |
| |
| struct cfs_rq cfs; |
| struct rt_rq rt; |
| |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| /* list of leaf cfs_rq on this cpu: */ |
| struct list_head leaf_cfs_rq_list; |
| #endif |
| #ifdef CONFIG_RT_GROUP_SCHED |
| struct list_head leaf_rt_rq_list; |
| #endif |
| |
| /* |
| * This is part of a global counter where only the total sum |
| * over all CPUs matters. A task can increase this counter on |
| * one CPU and if it got migrated afterwards it may decrease |
| * it on another CPU. Always updated under the runqueue lock: |
| */ |
| unsigned long nr_uninterruptible; |
| |
| struct task_struct *curr, *idle; |
| unsigned long next_balance; |
| struct mm_struct *prev_mm; |
| |
| u64 clock; |
| |
| atomic_t nr_iowait; |
| |
| #ifdef CONFIG_SMP |
| struct root_domain *rd; |
| struct sched_domain *sd; |
| |
| /* For active balancing */ |
| int active_balance; |
| int push_cpu; |
| /* cpu of this runqueue: */ |
| int cpu; |
| int online; |
| |
| unsigned long avg_load_per_task; |
| |
| struct task_struct *migration_thread; |
| struct list_head migration_queue; |
| #endif |
| |
| #ifdef CONFIG_SCHED_HRTICK |
| unsigned long hrtick_flags; |
| ktime_t hrtick_expire; |
| struct hrtimer hrtick_timer; |
| #endif |
| |
| #ifdef CONFIG_SCHEDSTATS |
| /* latency stats */ |
| struct sched_info rq_sched_info; |
| |
| /* sys_sched_yield() stats */ |
| unsigned int yld_exp_empty; |
| unsigned int yld_act_empty; |
| unsigned int yld_both_empty; |
| unsigned int yld_count; |
| |
| /* schedule() stats */ |
| unsigned int sched_switch; |
| unsigned int sched_count; |
| unsigned int sched_goidle; |
| |
| /* try_to_wake_up() stats */ |
| unsigned int ttwu_count; |
| unsigned int ttwu_local; |
| |
| /* BKL stats */ |
| unsigned int bkl_count; |
| #endif |
| struct lock_class_key rq_lock_key; |
| }; |
| |
| static DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); |
| |
| static inline void check_preempt_curr(struct rq *rq, struct task_struct *p) |
| { |
| rq->curr->sched_class->check_preempt_curr(rq, p); |
| } |
| |
| static inline int cpu_of(struct rq *rq) |
| { |
| #ifdef CONFIG_SMP |
| return rq->cpu; |
| #else |
| return 0; |
| #endif |
| } |
| |
| /* |
| * The domain tree (rq->sd) is protected by RCU's quiescent state transition. |
| * See detach_destroy_domains: synchronize_sched for details. |
| * |
| * The domain tree of any CPU may only be accessed from within |
| * preempt-disabled sections. |
| */ |
| #define for_each_domain(cpu, __sd) \ |
| for (__sd = rcu_dereference(cpu_rq(cpu)->sd); __sd; __sd = __sd->parent) |
| |
| #define cpu_rq(cpu) (&per_cpu(runqueues, (cpu))) |
| #define this_rq() (&__get_cpu_var(runqueues)) |
| #define task_rq(p) cpu_rq(task_cpu(p)) |
| #define cpu_curr(cpu) (cpu_rq(cpu)->curr) |
| |
| static inline void update_rq_clock(struct rq *rq) |
| { |
| rq->clock = sched_clock_cpu(cpu_of(rq)); |
| } |
| |
| /* |
| * Tunables that become constants when CONFIG_SCHED_DEBUG is off: |
| */ |
| #ifdef CONFIG_SCHED_DEBUG |
| # define const_debug __read_mostly |
| #else |
| # define const_debug static const |
| #endif |
| |
| /** |
| * runqueue_is_locked |
| * |
| * Returns true if the current cpu runqueue is locked. |
| * This interface allows printk to be called with the runqueue lock |
| * held and know whether or not it is OK to wake up the klogd. |
| */ |
| int runqueue_is_locked(void) |
| { |
| int cpu = get_cpu(); |
| struct rq *rq = cpu_rq(cpu); |
| int ret; |
| |
| ret = spin_is_locked(&rq->lock); |
| put_cpu(); |
| return ret; |
| } |
| |
| /* |
| * Debugging: various feature bits |
| */ |
| |
| #define SCHED_FEAT(name, enabled) \ |
| __SCHED_FEAT_##name , |
| |
| enum { |
| #include "sched_features.h" |
| }; |
| |
| #undef SCHED_FEAT |
| |
| #define SCHED_FEAT(name, enabled) \ |
| (1UL << __SCHED_FEAT_##name) * enabled | |
| |
| const_debug unsigned int sysctl_sched_features = |
| #include "sched_features.h" |
| 0; |
| |
| #undef SCHED_FEAT |
| |
| #ifdef CONFIG_SCHED_DEBUG |
| #define SCHED_FEAT(name, enabled) \ |
| #name , |
| |
| static __read_mostly char *sched_feat_names[] = { |
| #include "sched_features.h" |
| NULL |
| }; |
| |
| #undef SCHED_FEAT |
| |
| static int sched_feat_open(struct inode *inode, struct file *filp) |
| { |
| filp->private_data = inode->i_private; |
| return 0; |
| } |
| |
| static ssize_t |
| sched_feat_read(struct file *filp, char __user *ubuf, |
| size_t cnt, loff_t *ppos) |
| { |
| char *buf; |
| int r = 0; |
| int len = 0; |
| int i; |
| |
| for (i = 0; sched_feat_names[i]; i++) { |
| len += strlen(sched_feat_names[i]); |
| len += 4; |
| } |
| |
| buf = kmalloc(len + 2, GFP_KERNEL); |
| if (!buf) |
| return -ENOMEM; |
| |
| for (i = 0; sched_feat_names[i]; i++) { |
| if (sysctl_sched_features & (1UL << i)) |
| r += sprintf(buf + r, "%s ", sched_feat_names[i]); |
| else |
| r += sprintf(buf + r, "NO_%s ", sched_feat_names[i]); |
| } |
| |
| r += sprintf(buf + r, "\n"); |
| WARN_ON(r >= len + 2); |
| |
| r = simple_read_from_buffer(ubuf, cnt, ppos, buf, r); |
| |
| kfree(buf); |
| |
| return r; |
| } |
| |
| static ssize_t |
| sched_feat_write(struct file *filp, const char __user *ubuf, |
| size_t cnt, loff_t *ppos) |
| { |
| char buf[64]; |
| char *cmp = buf; |
| int neg = 0; |
| int i; |
| |
| if (cnt > 63) |
| cnt = 63; |
| |
| if (copy_from_user(&buf, ubuf, cnt)) |
| return -EFAULT; |
| |
| buf[cnt] = 0; |
| |
| if (strncmp(buf, "NO_", 3) == 0) { |
| neg = 1; |
| cmp += 3; |
| } |
| |
| for (i = 0; sched_feat_names[i]; i++) { |
| int len = strlen(sched_feat_names[i]); |
| |
| if (strncmp(cmp, sched_feat_names[i], len) == 0) { |
| if (neg) |
| sysctl_sched_features &= ~(1UL << i); |
| else |
| sysctl_sched_features |= (1UL << i); |
| break; |
| } |
| } |
| |
| if (!sched_feat_names[i]) |
| return -EINVAL; |
| |
| filp->f_pos += cnt; |
| |
| return cnt; |
| } |
| |
| static struct file_operations sched_feat_fops = { |
| .open = sched_feat_open, |
| .read = sched_feat_read, |
| .write = sched_feat_write, |
| }; |
| |
| static __init int sched_init_debug(void) |
| { |
| debugfs_create_file("sched_features", 0644, NULL, NULL, |
| &sched_feat_fops); |
| |
| return 0; |
| } |
| late_initcall(sched_init_debug); |
| |
| #endif |
| |
| #define sched_feat(x) (sysctl_sched_features & (1UL << __SCHED_FEAT_##x)) |
| |
| /* |
| * Number of tasks to iterate in a single balance run. |
| * Limited because this is done with IRQs disabled. |
| */ |
| const_debug unsigned int sysctl_sched_nr_migrate = 32; |
| |
| /* |
| * ratelimit for updating the group shares. |
| * default: 0.5ms |
| */ |
| const_debug unsigned int sysctl_sched_shares_ratelimit = 500000; |
| |
| /* |
| * period over which we measure -rt task cpu usage in us. |
| * default: 1s |
| */ |
| unsigned int sysctl_sched_rt_period = 1000000; |
| |
| static __read_mostly int scheduler_running; |
| |
| /* |
| * part of the period that we allow rt tasks to run in us. |
| * default: 0.95s |
| */ |
| int sysctl_sched_rt_runtime = 950000; |
| |
| static inline u64 global_rt_period(void) |
| { |
| return (u64)sysctl_sched_rt_period * NSEC_PER_USEC; |
| } |
| |
| static inline u64 global_rt_runtime(void) |
| { |
| if (sysctl_sched_rt_period < 0) |
| return RUNTIME_INF; |
| |
| return (u64)sysctl_sched_rt_runtime * NSEC_PER_USEC; |
| } |
| |
| #ifndef prepare_arch_switch |
| # define prepare_arch_switch(next) do { } while (0) |
| #endif |
| #ifndef finish_arch_switch |
| # define finish_arch_switch(prev) do { } while (0) |
| #endif |
| |
| static inline int task_current(struct rq *rq, struct task_struct *p) |
| { |
| return rq->curr == p; |
| } |
| |
| #ifndef __ARCH_WANT_UNLOCKED_CTXSW |
| static inline int task_running(struct rq *rq, struct task_struct *p) |
| { |
| return task_current(rq, p); |
| } |
| |
| static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
| { |
| } |
| |
| static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
| { |
| #ifdef CONFIG_DEBUG_SPINLOCK |
| /* this is a valid case when another task releases the spinlock */ |
| rq->lock.owner = current; |
| #endif |
| /* |
| * If we are tracking spinlock dependencies then we have to |
| * fix up the runqueue lock - which gets 'carried over' from |
| * prev into current: |
| */ |
| spin_acquire(&rq->lock.dep_map, 0, 0, _THIS_IP_); |
| |
| spin_unlock_irq(&rq->lock); |
| } |
| |
| #else /* __ARCH_WANT_UNLOCKED_CTXSW */ |
| static inline int task_running(struct rq *rq, struct task_struct *p) |
| { |
| #ifdef CONFIG_SMP |
| return p->oncpu; |
| #else |
| return task_current(rq, p); |
| #endif |
| } |
| |
| static inline void prepare_lock_switch(struct rq *rq, struct task_struct *next) |
| { |
| #ifdef CONFIG_SMP |
| /* |
| * We can optimise this out completely for !SMP, because the |
| * SMP rebalancing from interrupt is the only thing that cares |
| * here. |
| */ |
| next->oncpu = 1; |
| #endif |
| #ifdef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
| spin_unlock_irq(&rq->lock); |
| #else |
| spin_unlock(&rq->lock); |
| #endif |
| } |
| |
| static inline void finish_lock_switch(struct rq *rq, struct task_struct *prev) |
| { |
| #ifdef CONFIG_SMP |
| /* |
| * After ->oncpu is cleared, the task can be moved to a different CPU. |
| * We must ensure this doesn't happen until the switch is completely |
| * finished. |
| */ |
| smp_wmb(); |
| prev->oncpu = 0; |
| #endif |
| #ifndef __ARCH_WANT_INTERRUPTS_ON_CTXSW |
| local_irq_enable(); |
| #endif |
| } |
| #endif /* __ARCH_WANT_UNLOCKED_CTXSW */ |
| |
| /* |
| * __task_rq_lock - lock the runqueue a given task resides on. |
| * Must be called interrupts disabled. |
| */ |
| static inline struct rq *__task_rq_lock(struct task_struct *p) |
| __acquires(rq->lock) |
| { |
| for (;;) { |
| struct rq *rq = task_rq(p); |
| spin_lock(&rq->lock); |
| if (likely(rq == task_rq(p))) |
| return rq; |
| spin_unlock(&rq->lock); |
| } |
| } |
| |
| /* |
| * task_rq_lock - lock the runqueue a given task resides on and disable |
| * interrupts. Note the ordering: we can safely lookup the task_rq without |
| * explicitly disabling preemption. |
| */ |
| static struct rq *task_rq_lock(struct task_struct *p, unsigned long *flags) |
| __acquires(rq->lock) |
| { |
| struct rq *rq; |
| |
| for (;;) { |
| local_irq_save(*flags); |
| rq = task_rq(p); |
| spin_lock(&rq->lock); |
| if (likely(rq == task_rq(p))) |
| return rq; |
| spin_unlock_irqrestore(&rq->lock, *flags); |
| } |
| } |
| |
| static void __task_rq_unlock(struct rq *rq) |
| __releases(rq->lock) |
| { |
| spin_unlock(&rq->lock); |
| } |
| |
| static inline void task_rq_unlock(struct rq *rq, unsigned long *flags) |
| __releases(rq->lock) |
| { |
| spin_unlock_irqrestore(&rq->lock, *flags); |
| } |
| |
| /* |
| * this_rq_lock - lock this runqueue and disable interrupts. |
| */ |
| static struct rq *this_rq_lock(void) |
| __acquires(rq->lock) |
| { |
| struct rq *rq; |
| |
| local_irq_disable(); |
| rq = this_rq(); |
| spin_lock(&rq->lock); |
| |
| return rq; |
| } |
| |
| static void __resched_task(struct task_struct *p, int tif_bit); |
| |
| static inline void resched_task(struct task_struct *p) |
| { |
| __resched_task(p, TIF_NEED_RESCHED); |
| } |
| |
| #ifdef CONFIG_SCHED_HRTICK |
| /* |
| * Use HR-timers to deliver accurate preemption points. |
| * |
| * Its all a bit involved since we cannot program an hrt while holding the |
| * rq->lock. So what we do is store a state in in rq->hrtick_* and ask for a |
| * reschedule event. |
| * |
| * When we get rescheduled we reprogram the hrtick_timer outside of the |
| * rq->lock. |
| */ |
| static inline void resched_hrt(struct task_struct *p) |
| { |
| __resched_task(p, TIF_HRTICK_RESCHED); |
| } |
| |
| static inline void resched_rq(struct rq *rq) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&rq->lock, flags); |
| resched_task(rq->curr); |
| spin_unlock_irqrestore(&rq->lock, flags); |
| } |
| |
| enum { |
| HRTICK_SET, /* re-programm hrtick_timer */ |
| HRTICK_RESET, /* not a new slice */ |
| HRTICK_BLOCK, /* stop hrtick operations */ |
| }; |
| |
| /* |
| * Use hrtick when: |
| * - enabled by features |
| * - hrtimer is actually high res |
| */ |
| static inline int hrtick_enabled(struct rq *rq) |
| { |
| if (!sched_feat(HRTICK)) |
| return 0; |
| if (unlikely(test_bit(HRTICK_BLOCK, &rq->hrtick_flags))) |
| return 0; |
| return hrtimer_is_hres_active(&rq->hrtick_timer); |
| } |
| |
| /* |
| * Called to set the hrtick timer state. |
| * |
| * called with rq->lock held and irqs disabled |
| */ |
| static void hrtick_start(struct rq *rq, u64 delay, int reset) |
| { |
| assert_spin_locked(&rq->lock); |
| |
| /* |
| * preempt at: now + delay |
| */ |
| rq->hrtick_expire = |
| ktime_add_ns(rq->hrtick_timer.base->get_time(), delay); |
| /* |
| * indicate we need to program the timer |
| */ |
| __set_bit(HRTICK_SET, &rq->hrtick_flags); |
| if (reset) |
| __set_bit(HRTICK_RESET, &rq->hrtick_flags); |
| |
| /* |
| * New slices are called from the schedule path and don't need a |
| * forced reschedule. |
| */ |
| if (reset) |
| resched_hrt(rq->curr); |
| } |
| |
| static void hrtick_clear(struct rq *rq) |
| { |
| if (hrtimer_active(&rq->hrtick_timer)) |
| hrtimer_cancel(&rq->hrtick_timer); |
| } |
| |
| /* |
| * Update the timer from the possible pending state. |
| */ |
| static void hrtick_set(struct rq *rq) |
| { |
| ktime_t time; |
| int set, reset; |
| unsigned long flags; |
| |
| WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); |
| |
| spin_lock_irqsave(&rq->lock, flags); |
| set = __test_and_clear_bit(HRTICK_SET, &rq->hrtick_flags); |
| reset = __test_and_clear_bit(HRTICK_RESET, &rq->hrtick_flags); |
| time = rq->hrtick_expire; |
| clear_thread_flag(TIF_HRTICK_RESCHED); |
| spin_unlock_irqrestore(&rq->lock, flags); |
| |
| if (set) { |
| hrtimer_start(&rq->hrtick_timer, time, HRTIMER_MODE_ABS); |
| if (reset && !hrtimer_active(&rq->hrtick_timer)) |
| resched_rq(rq); |
| } else |
| hrtick_clear(rq); |
| } |
| |
| /* |
| * High-resolution timer tick. |
| * Runs from hardirq context with interrupts disabled. |
| */ |
| static enum hrtimer_restart hrtick(struct hrtimer *timer) |
| { |
| struct rq *rq = container_of(timer, struct rq, hrtick_timer); |
| |
| WARN_ON_ONCE(cpu_of(rq) != smp_processor_id()); |
| |
| spin_lock(&rq->lock); |
| update_rq_clock(rq); |
| rq->curr->sched_class->task_tick(rq, rq->curr, 1); |
| spin_unlock(&rq->lock); |
| |
| return HRTIMER_NORESTART; |
| } |
| |
| #ifdef CONFIG_SMP |
| static void hotplug_hrtick_disable(int cpu) |
| { |
| struct rq *rq = cpu_rq(cpu); |
| unsigned long flags; |
| |
| spin_lock_irqsave(&rq->lock, flags); |
| rq->hrtick_flags = 0; |
| __set_bit(HRTICK_BLOCK, &rq->hrtick_flags); |
| spin_unlock_irqrestore(&rq->lock, flags); |
| |
| hrtick_clear(rq); |
| } |
| |
| static void hotplug_hrtick_enable(int cpu) |
| { |
| struct rq *rq = cpu_rq(cpu); |
| unsigned long flags; |
| |
| spin_lock_irqsave(&rq->lock, flags); |
| __clear_bit(HRTICK_BLOCK, &rq->hrtick_flags); |
| spin_unlock_irqrestore(&rq->lock, flags); |
| } |
| |
| static int |
| hotplug_hrtick(struct notifier_block *nfb, unsigned long action, void *hcpu) |
| { |
| int cpu = (int)(long)hcpu; |
| |
| switch (action) { |
| case CPU_UP_CANCELED: |
| case CPU_UP_CANCELED_FROZEN: |
| case CPU_DOWN_PREPARE: |
| case CPU_DOWN_PREPARE_FROZEN: |
| case CPU_DEAD: |
| case CPU_DEAD_FROZEN: |
| hotplug_hrtick_disable(cpu); |
| return NOTIFY_OK; |
| |
| case CPU_UP_PREPARE: |
| case CPU_UP_PREPARE_FROZEN: |
| case CPU_DOWN_FAILED: |
| case CPU_DOWN_FAILED_FROZEN: |
| case CPU_ONLINE: |
| case CPU_ONLINE_FROZEN: |
| hotplug_hrtick_enable(cpu); |
| return NOTIFY_OK; |
| } |
| |
| return NOTIFY_DONE; |
| } |
| |
| static void init_hrtick(void) |
| { |
| hotcpu_notifier(hotplug_hrtick, 0); |
| } |
| #endif /* CONFIG_SMP */ |
| |
| static void init_rq_hrtick(struct rq *rq) |
| { |
| rq->hrtick_flags = 0; |
| hrtimer_init(&rq->hrtick_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
| rq->hrtick_timer.function = hrtick; |
| rq->hrtick_timer.cb_mode = HRTIMER_CB_IRQSAFE_NO_SOFTIRQ; |
| } |
| |
| void hrtick_resched(void) |
| { |
| struct rq *rq; |
| unsigned long flags; |
| |
| if (!test_thread_flag(TIF_HRTICK_RESCHED)) |
| return; |
| |
| local_irq_save(flags); |
| rq = cpu_rq(smp_processor_id()); |
| hrtick_set(rq); |
| local_irq_restore(flags); |
| } |
| #else |
| static inline void hrtick_clear(struct rq *rq) |
| { |
| } |
| |
| static inline void hrtick_set(struct rq *rq) |
| { |
| } |
| |
| static inline void init_rq_hrtick(struct rq *rq) |
| { |
| } |
| |
| void hrtick_resched(void) |
| { |
| } |
| |
| static inline void init_hrtick(void) |
| { |
| } |
| #endif |
| |
| /* |
| * resched_task - mark a task 'to be rescheduled now'. |
| * |
| * On UP this means the setting of the need_resched flag, on SMP it |
| * might also involve a cross-CPU call to trigger the scheduler on |
| * the target CPU. |
| */ |
| #ifdef CONFIG_SMP |
| |
| #ifndef tsk_is_polling |
| #define tsk_is_polling(t) test_tsk_thread_flag(t, TIF_POLLING_NRFLAG) |
| #endif |
| |
| static void __resched_task(struct task_struct *p, int tif_bit) |
| { |
| int cpu; |
| |
| assert_spin_locked(&task_rq(p)->lock); |
| |
| if (unlikely(test_tsk_thread_flag(p, tif_bit))) |
| return; |
| |
| set_tsk_thread_flag(p, tif_bit); |
| |
| cpu = task_cpu(p); |
| if (cpu == smp_processor_id()) |
| return; |
| |
| /* NEED_RESCHED must be visible before we test polling */ |
| smp_mb(); |
| if (!tsk_is_polling(p)) |
| smp_send_reschedule(cpu); |
| } |
| |
| static void resched_cpu(int cpu) |
| { |
| struct rq *rq = cpu_rq(cpu); |
| unsigned long flags; |
| |
| if (!spin_trylock_irqsave(&rq->lock, flags)) |
| return; |
| resched_task(cpu_curr(cpu)); |
| spin_unlock_irqrestore(&rq->lock, flags); |
| } |
| |
| #ifdef CONFIG_NO_HZ |
| /* |
| * When add_timer_on() enqueues a timer into the timer wheel of an |
| * idle CPU then this timer might expire before the next timer event |
| * which is scheduled to wake up that CPU. In case of a completely |
| * idle system the next event might even be infinite time into the |
| * future. wake_up_idle_cpu() ensures that the CPU is woken up and |
| * leaves the inner idle loop so the newly added timer is taken into |
| * account when the CPU goes back to idle and evaluates the timer |
| * wheel for the next timer event. |
| */ |
| void wake_up_idle_cpu(int cpu) |
| { |
| struct rq *rq = cpu_rq(cpu); |
| |
| if (cpu == smp_processor_id()) |
| return; |
| |
| /* |
| * This is safe, as this function is called with the timer |
| * wheel base lock of (cpu) held. When the CPU is on the way |
| * to idle and has not yet set rq->curr to idle then it will |
| * be serialized on the timer wheel base lock and take the new |
| * timer into account automatically. |
| */ |
| if (rq->curr != rq->idle) |
| return; |
| |
| /* |
| * We can set TIF_RESCHED on the idle task of the other CPU |
| * lockless. The worst case is that the other CPU runs the |
| * idle task through an additional NOOP schedule() |
| */ |
| set_tsk_thread_flag(rq->idle, TIF_NEED_RESCHED); |
| |
| /* NEED_RESCHED must be visible before we test polling */ |
| smp_mb(); |
| if (!tsk_is_polling(rq->idle)) |
| smp_send_reschedule(cpu); |
| } |
| #endif /* CONFIG_NO_HZ */ |
| |
| #else /* !CONFIG_SMP */ |
| static void __resched_task(struct task_struct *p, int tif_bit) |
| { |
| assert_spin_locked(&task_rq(p)->lock); |
| set_tsk_thread_flag(p, tif_bit); |
| } |
| #endif /* CONFIG_SMP */ |
| |
| #if BITS_PER_LONG == 32 |
| # define WMULT_CONST (~0UL) |
| #else |
| # define WMULT_CONST (1UL << 32) |
| #endif |
| |
| #define WMULT_SHIFT 32 |
| |
| /* |
| * Shift right and round: |
| */ |
| #define SRR(x, y) (((x) + (1UL << ((y) - 1))) >> (y)) |
| |
| /* |
| * delta *= weight / lw |
| */ |
| static unsigned long |
| calc_delta_mine(unsigned long delta_exec, unsigned long weight, |
| struct load_weight *lw) |
| { |
| u64 tmp; |
| |
| if (!lw->inv_weight) { |
| if (BITS_PER_LONG > 32 && unlikely(lw->weight >= WMULT_CONST)) |
| lw->inv_weight = 1; |
| else |
| lw->inv_weight = 1 + (WMULT_CONST-lw->weight/2) |
| / (lw->weight+1); |
| } |
| |
| tmp = (u64)delta_exec * weight; |
| /* |
| * Check whether we'd overflow the 64-bit multiplication: |
| */ |
| if (unlikely(tmp > WMULT_CONST)) |
| tmp = SRR(SRR(tmp, WMULT_SHIFT/2) * lw->inv_weight, |
| WMULT_SHIFT/2); |
| else |
| tmp = SRR(tmp * lw->inv_weight, WMULT_SHIFT); |
| |
| return (unsigned long)min(tmp, (u64)(unsigned long)LONG_MAX); |
| } |
| |
| static inline void update_load_add(struct load_weight *lw, unsigned long inc) |
| { |
| lw->weight += inc; |
| lw->inv_weight = 0; |
| } |
| |
| static inline void update_load_sub(struct load_weight *lw, unsigned long dec) |
| { |
| lw->weight -= dec; |
| lw->inv_weight = 0; |
| } |
| |
| /* |
| * To aid in avoiding the subversion of "niceness" due to uneven distribution |
| * of tasks with abnormal "nice" values across CPUs the contribution that |
| * each task makes to its run queue's load is weighted according to its |
| * scheduling class and "nice" value. For SCHED_NORMAL tasks this is just a |
| * scaled version of the new time slice allocation that they receive on time |
| * slice expiry etc. |
| */ |
| |
| #define WEIGHT_IDLEPRIO 2 |
| #define WMULT_IDLEPRIO (1 << 31) |
| |
| /* |
| * Nice levels are multiplicative, with a gentle 10% change for every |
| * nice level changed. I.e. when a CPU-bound task goes from nice 0 to |
| * nice 1, it will get ~10% less CPU time than another CPU-bound task |
| * that remained on nice 0. |
| * |
| * The "10% effect" is relative and cumulative: from _any_ nice level, |
| * if you go up 1 level, it's -10% CPU usage, if you go down 1 level |
| * it's +10% CPU usage. (to achieve that we use a multiplier of 1.25. |
| * If a task goes up by ~10% and another task goes down by ~10% then |
| * the relative distance between them is ~25%.) |
| */ |
| static const int prio_to_weight[40] = { |
| /* -20 */ 88761, 71755, 56483, 46273, 36291, |
| /* -15 */ 29154, 23254, 18705, 14949, 11916, |
| /* -10 */ 9548, 7620, 6100, 4904, 3906, |
| /* -5 */ 3121, 2501, 1991, 1586, 1277, |
| /* 0 */ 1024, 820, 655, 526, 423, |
| /* 5 */ 335, 272, 215, 172, 137, |
| /* 10 */ 110, 87, 70, 56, 45, |
| /* 15 */ 36, 29, 23, 18, 15, |
| }; |
| |
| /* |
| * Inverse (2^32/x) values of the prio_to_weight[] array, precalculated. |
| * |
| * In cases where the weight does not change often, we can use the |
| * precalculated inverse to speed up arithmetics by turning divisions |
| * into multiplications: |
| */ |
| static const u32 prio_to_wmult[40] = { |
| /* -20 */ 48388, 59856, 76040, 92818, 118348, |
| /* -15 */ 147320, 184698, 229616, 287308, 360437, |
| /* -10 */ 449829, 563644, 704093, 875809, 1099582, |
| /* -5 */ 1376151, 1717300, 2157191, 2708050, 3363326, |
| /* 0 */ 4194304, 5237765, 6557202, 8165337, 10153587, |
| /* 5 */ 12820798, 15790321, 19976592, 24970740, 31350126, |
| /* 10 */ 39045157, 49367440, 61356676, 76695844, 95443717, |
| /* 15 */ 119304647, 148102320, 186737708, 238609294, 286331153, |
| }; |
| |
| static void activate_task(struct rq *rq, struct task_struct *p, int wakeup); |
| |
| /* |
| * runqueue iterator, to support SMP load-balancing between different |
| * scheduling classes, without having to expose their internal data |
| * structures to the load-balancing proper: |
| */ |
| struct rq_iterator { |
| void *arg; |
| struct task_struct *(*start)(void *); |
| struct task_struct *(*next)(void *); |
| }; |
| |
| #ifdef CONFIG_SMP |
| static unsigned long |
| balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, |
| unsigned long max_load_move, struct sched_domain *sd, |
| enum cpu_idle_type idle, int *all_pinned, |
| int *this_best_prio, struct rq_iterator *iterator); |
| |
| static int |
| iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, |
| struct sched_domain *sd, enum cpu_idle_type idle, |
| struct rq_iterator *iterator); |
| #endif |
| |
| #ifdef CONFIG_CGROUP_CPUACCT |
| static void cpuacct_charge(struct task_struct *tsk, u64 cputime); |
| #else |
| static inline void cpuacct_charge(struct task_struct *tsk, u64 cputime) {} |
| #endif |
| |
| static inline void inc_cpu_load(struct rq *rq, unsigned long load) |
| { |
| update_load_add(&rq->load, load); |
| } |
| |
| static inline void dec_cpu_load(struct rq *rq, unsigned long load) |
| { |
| update_load_sub(&rq->load, load); |
| } |
| |
| #ifdef CONFIG_SMP |
| static unsigned long source_load(int cpu, int type); |
| static unsigned long target_load(int cpu, int type); |
| static int task_hot(struct task_struct *p, u64 now, struct sched_domain *sd); |
| |
| static unsigned long cpu_avg_load_per_task(int cpu) |
| { |
| struct rq *rq = cpu_rq(cpu); |
| |
| if (rq->nr_running) |
| rq->avg_load_per_task = rq->load.weight / rq->nr_running; |
| |
| return rq->avg_load_per_task; |
| } |
| |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| |
| typedef void (*tg_visitor)(struct task_group *, int, struct sched_domain *); |
| |
| /* |
| * Iterate the full tree, calling @down when first entering a node and @up when |
| * leaving it for the final time. |
| */ |
| static void |
| walk_tg_tree(tg_visitor down, tg_visitor up, int cpu, struct sched_domain *sd) |
| { |
| struct task_group *parent, *child; |
| |
| rcu_read_lock(); |
| parent = &root_task_group; |
| down: |
| (*down)(parent, cpu, sd); |
| list_for_each_entry_rcu(child, &parent->children, siblings) { |
| parent = child; |
| goto down; |
| |
| up: |
| continue; |
| } |
| (*up)(parent, cpu, sd); |
| |
| child = parent; |
| parent = parent->parent; |
| if (parent) |
| goto up; |
| rcu_read_unlock(); |
| } |
| |
| static void __set_se_shares(struct sched_entity *se, unsigned long shares); |
| |
| /* |
| * Calculate and set the cpu's group shares. |
| */ |
| static void |
| __update_group_shares_cpu(struct task_group *tg, int cpu, |
| unsigned long sd_shares, unsigned long sd_rq_weight) |
| { |
| int boost = 0; |
| unsigned long shares; |
| unsigned long rq_weight; |
| |
| if (!tg->se[cpu]) |
| return; |
| |
| rq_weight = tg->cfs_rq[cpu]->load.weight; |
| |
| /* |
| * If there are currently no tasks on the cpu pretend there is one of |
| * average load so that when a new task gets to run here it will not |
| * get delayed by group starvation. |
| */ |
| if (!rq_weight) { |
| boost = 1; |
| rq_weight = NICE_0_LOAD; |
| } |
| |
| if (unlikely(rq_weight > sd_rq_weight)) |
| rq_weight = sd_rq_weight; |
| |
| /* |
| * \Sum shares * rq_weight |
| * shares = ----------------------- |
| * \Sum rq_weight |
| * |
| */ |
| shares = (sd_shares * rq_weight) / (sd_rq_weight + 1); |
| |
| /* |
| * record the actual number of shares, not the boosted amount. |
| */ |
| tg->cfs_rq[cpu]->shares = boost ? 0 : shares; |
| tg->cfs_rq[cpu]->rq_weight = rq_weight; |
| |
| if (shares < MIN_SHARES) |
| shares = MIN_SHARES; |
| else if (shares > MAX_SHARES) |
| shares = MAX_SHARES; |
| |
| __set_se_shares(tg->se[cpu], shares); |
| } |
| |
| /* |
| * Re-compute the task group their per cpu shares over the given domain. |
| * This needs to be done in a bottom-up fashion because the rq weight of a |
| * parent group depends on the shares of its child groups. |
| */ |
| static void |
| tg_shares_up(struct task_group *tg, int cpu, struct sched_domain *sd) |
| { |
| unsigned long rq_weight = 0; |
| unsigned long shares = 0; |
| int i; |
| |
| for_each_cpu_mask(i, sd->span) { |
| rq_weight += tg->cfs_rq[i]->load.weight; |
| shares += tg->cfs_rq[i]->shares; |
| } |
| |
| if ((!shares && rq_weight) || shares > tg->shares) |
| shares = tg->shares; |
| |
| if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE)) |
| shares = tg->shares; |
| |
| if (!rq_weight) |
| rq_weight = cpus_weight(sd->span) * NICE_0_LOAD; |
| |
| for_each_cpu_mask(i, sd->span) { |
| struct rq *rq = cpu_rq(i); |
| unsigned long flags; |
| |
| spin_lock_irqsave(&rq->lock, flags); |
| __update_group_shares_cpu(tg, i, shares, rq_weight); |
| spin_unlock_irqrestore(&rq->lock, flags); |
| } |
| } |
| |
| /* |
| * Compute the cpu's hierarchical load factor for each task group. |
| * This needs to be done in a top-down fashion because the load of a child |
| * group is a fraction of its parents load. |
| */ |
| static void |
| tg_load_down(struct task_group *tg, int cpu, struct sched_domain *sd) |
| { |
| unsigned long load; |
| |
| if (!tg->parent) { |
| load = cpu_rq(cpu)->load.weight; |
| } else { |
| load = tg->parent->cfs_rq[cpu]->h_load; |
| load *= tg->cfs_rq[cpu]->shares; |
| load /= tg->parent->cfs_rq[cpu]->load.weight + 1; |
| } |
| |
| tg->cfs_rq[cpu]->h_load = load; |
| } |
| |
| static void |
| tg_nop(struct task_group *tg, int cpu, struct sched_domain *sd) |
| { |
| } |
| |
| static void update_shares(struct sched_domain *sd) |
| { |
| u64 now = cpu_clock(raw_smp_processor_id()); |
| s64 elapsed = now - sd->last_update; |
| |
| if (elapsed >= (s64)(u64)sysctl_sched_shares_ratelimit) { |
| sd->last_update = now; |
| walk_tg_tree(tg_nop, tg_shares_up, 0, sd); |
| } |
| } |
| |
| static void update_shares_locked(struct rq *rq, struct sched_domain *sd) |
| { |
| spin_unlock(&rq->lock); |
| update_shares(sd); |
| spin_lock(&rq->lock); |
| } |
| |
| static void update_h_load(int cpu) |
| { |
| walk_tg_tree(tg_load_down, tg_nop, cpu, NULL); |
| } |
| |
| #else |
| |
| static inline void update_shares(struct sched_domain *sd) |
| { |
| } |
| |
| static inline void update_shares_locked(struct rq *rq, struct sched_domain *sd) |
| { |
| } |
| |
| #endif |
| |
| #endif |
| |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| static void cfs_rq_set_shares(struct cfs_rq *cfs_rq, unsigned long shares) |
| { |
| #ifdef CONFIG_SMP |
| cfs_rq->shares = shares; |
| #endif |
| } |
| #endif |
| |
| #include "sched_stats.h" |
| #include "sched_idletask.c" |
| #include "sched_fair.c" |
| #include "sched_rt.c" |
| #ifdef CONFIG_SCHED_DEBUG |
| # include "sched_debug.c" |
| #endif |
| |
| #define sched_class_highest (&rt_sched_class) |
| #define for_each_class(class) \ |
| for (class = sched_class_highest; class; class = class->next) |
| |
| static void inc_nr_running(struct rq *rq) |
| { |
| rq->nr_running++; |
| } |
| |
| static void dec_nr_running(struct rq *rq) |
| { |
| rq->nr_running--; |
| } |
| |
| static void set_load_weight(struct task_struct *p) |
| { |
| if (task_has_rt_policy(p)) { |
| p->se.load.weight = prio_to_weight[0] * 2; |
| p->se.load.inv_weight = prio_to_wmult[0] >> 1; |
| return; |
| } |
| |
| /* |
| * SCHED_IDLE tasks get minimal weight: |
| */ |
| if (p->policy == SCHED_IDLE) { |
| p->se.load.weight = WEIGHT_IDLEPRIO; |
| p->se.load.inv_weight = WMULT_IDLEPRIO; |
| return; |
| } |
| |
| p->se.load.weight = prio_to_weight[p->static_prio - MAX_RT_PRIO]; |
| p->se.load.inv_weight = prio_to_wmult[p->static_prio - MAX_RT_PRIO]; |
| } |
| |
| static void update_avg(u64 *avg, u64 sample) |
| { |
| s64 diff = sample - *avg; |
| *avg += diff >> 3; |
| } |
| |
| static void enqueue_task(struct rq *rq, struct task_struct *p, int wakeup) |
| { |
| sched_info_queued(p); |
| p->sched_class->enqueue_task(rq, p, wakeup); |
| p->se.on_rq = 1; |
| } |
| |
| static void dequeue_task(struct rq *rq, struct task_struct *p, int sleep) |
| { |
| if (sleep && p->se.last_wakeup) { |
| update_avg(&p->se.avg_overlap, |
| p->se.sum_exec_runtime - p->se.last_wakeup); |
| p->se.last_wakeup = 0; |
| } |
| |
| sched_info_dequeued(p); |
| p->sched_class->dequeue_task(rq, p, sleep); |
| p->se.on_rq = 0; |
| } |
| |
| /* |
| * __normal_prio - return the priority that is based on the static prio |
| */ |
| static inline int __normal_prio(struct task_struct *p) |
| { |
| return p->static_prio; |
| } |
| |
| /* |
| * Calculate the expected normal priority: i.e. priority |
| * without taking RT-inheritance into account. Might be |
| * boosted by interactivity modifiers. Changes upon fork, |
| * setprio syscalls, and whenever the interactivity |
| * estimator recalculates. |
| */ |
| static inline int normal_prio(struct task_struct *p) |
| { |
| int prio; |
| |
| if (task_has_rt_policy(p)) |
| prio = MAX_RT_PRIO-1 - p->rt_priority; |
| else |
| prio = __normal_prio(p); |
| return prio; |
| } |
| |
| /* |
| * Calculate the current priority, i.e. the priority |
| * taken into account by the scheduler. This value might |
| * be boosted by RT tasks, or might be boosted by |
| * interactivity modifiers. Will be RT if the task got |
| * RT-boosted. If not then it returns p->normal_prio. |
| */ |
| static int effective_prio(struct task_struct *p) |
| { |
| p->normal_prio = normal_prio(p); |
| /* |
| * If we are RT tasks or we were boosted to RT priority, |
| * keep the priority unchanged. Otherwise, update priority |
| * to the normal priority: |
| */ |
| if (!rt_prio(p->prio)) |
| return p->normal_prio; |
| return p->prio; |
| } |
| |
| /* |
| * activate_task - move a task to the runqueue. |
| */ |
| static void activate_task(struct rq *rq, struct task_struct *p, int wakeup) |
| { |
| if (task_contributes_to_load(p)) |
| rq->nr_uninterruptible--; |
| |
| enqueue_task(rq, p, wakeup); |
| inc_nr_running(rq); |
| } |
| |
| /* |
| * deactivate_task - remove a task from the runqueue. |
| */ |
| static void deactivate_task(struct rq *rq, struct task_struct *p, int sleep) |
| { |
| if (task_contributes_to_load(p)) |
| rq->nr_uninterruptible++; |
| |
| dequeue_task(rq, p, sleep); |
| dec_nr_running(rq); |
| } |
| |
| /** |
| * task_curr - is this task currently executing on a CPU? |
| * @p: the task in question. |
| */ |
| inline int task_curr(const struct task_struct *p) |
| { |
| return cpu_curr(task_cpu(p)) == p; |
| } |
| |
| static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) |
| { |
| set_task_rq(p, cpu); |
| #ifdef CONFIG_SMP |
| /* |
| * After ->cpu is set up to a new value, task_rq_lock(p, ...) can be |
| * successfuly executed on another CPU. We must ensure that updates of |
| * per-task data have been completed by this moment. |
| */ |
| smp_wmb(); |
| task_thread_info(p)->cpu = cpu; |
| #endif |
| } |
| |
| static inline void check_class_changed(struct rq *rq, struct task_struct *p, |
| const struct sched_class *prev_class, |
| int oldprio, int running) |
| { |
| if (prev_class != p->sched_class) { |
| if (prev_class->switched_from) |
| prev_class->switched_from(rq, p, running); |
| p->sched_class->switched_to(rq, p, running); |
| } else |
| p->sched_class->prio_changed(rq, p, oldprio, running); |
| } |
| |
| #ifdef CONFIG_SMP |
| |
| /* Used instead of source_load when we know the type == 0 */ |
| static unsigned long weighted_cpuload(const int cpu) |
| { |
| return cpu_rq(cpu)->load.weight; |
| } |
| |
| /* |
| * Is this task likely cache-hot: |
| */ |
| static int |
| task_hot(struct task_struct *p, u64 now, struct sched_domain *sd) |
| { |
| s64 delta; |
| |
| /* |
| * Buddy candidates are cache hot: |
| */ |
| if (sched_feat(CACHE_HOT_BUDDY) && (&p->se == cfs_rq_of(&p->se)->next)) |
| return 1; |
| |
| if (p->sched_class != &fair_sched_class) |
| return 0; |
| |
| if (sysctl_sched_migration_cost == -1) |
| return 1; |
| if (sysctl_sched_migration_cost == 0) |
| return 0; |
| |
| delta = now - p->se.exec_start; |
| |
| return delta < (s64)sysctl_sched_migration_cost; |
| } |
| |
| |
| void set_task_cpu(struct task_struct *p, unsigned int new_cpu) |
| { |
| int old_cpu = task_cpu(p); |
| struct rq *old_rq = cpu_rq(old_cpu), *new_rq = cpu_rq(new_cpu); |
| struct cfs_rq *old_cfsrq = task_cfs_rq(p), |
| *new_cfsrq = cpu_cfs_rq(old_cfsrq, new_cpu); |
| u64 clock_offset; |
| |
| clock_offset = old_rq->clock - new_rq->clock; |
| |
| #ifdef CONFIG_SCHEDSTATS |
| if (p->se.wait_start) |
| p->se.wait_start -= clock_offset; |
| if (p->se.sleep_start) |
| p->se.sleep_start -= clock_offset; |
| if (p->se.block_start) |
| p->se.block_start -= clock_offset; |
| if (old_cpu != new_cpu) { |
| schedstat_inc(p, se.nr_migrations); |
| if (task_hot(p, old_rq->clock, NULL)) |
| schedstat_inc(p, se.nr_forced2_migrations); |
| } |
| #endif |
| p->se.vruntime -= old_cfsrq->min_vruntime - |
| new_cfsrq->min_vruntime; |
| |
| __set_task_cpu(p, new_cpu); |
| } |
| |
| struct migration_req { |
| struct list_head list; |
| |
| struct task_struct *task; |
| int dest_cpu; |
| |
| struct completion done; |
| }; |
| |
| /* |
| * The task's runqueue lock must be held. |
| * Returns true if you have to wait for migration thread. |
| */ |
| static int |
| migrate_task(struct task_struct *p, int dest_cpu, struct migration_req *req) |
| { |
| struct rq *rq = task_rq(p); |
| |
| /* |
| * If the task is not on a runqueue (and not running), then |
| * it is sufficient to simply update the task's cpu field. |
| */ |
| if (!p->se.on_rq && !task_running(rq, p)) { |
| set_task_cpu(p, dest_cpu); |
| return 0; |
| } |
| |
| init_completion(&req->done); |
| req->task = p; |
| req->dest_cpu = dest_cpu; |
| list_add(&req->list, &rq->migration_queue); |
| |
| return 1; |
| } |
| |
| /* |
| * wait_task_inactive - wait for a thread to unschedule. |
| * |
| * The caller must ensure that the task *will* unschedule sometime soon, |
| * else this function might spin for a *long* time. This function can't |
| * be called with interrupts off, or it may introduce deadlock with |
| * smp_call_function() if an IPI is sent by the same process we are |
| * waiting to become inactive. |
| */ |
| void wait_task_inactive(struct task_struct *p) |
| { |
| unsigned long flags; |
| int running, on_rq; |
| struct rq *rq; |
| |
| for (;;) { |
| /* |
| * We do the initial early heuristics without holding |
| * any task-queue locks at all. We'll only try to get |
| * the runqueue lock when things look like they will |
| * work out! |
| */ |
| rq = task_rq(p); |
| |
| /* |
| * If the task is actively running on another CPU |
| * still, just relax and busy-wait without holding |
| * any locks. |
| * |
| * NOTE! Since we don't hold any locks, it's not |
| * even sure that "rq" stays as the right runqueue! |
| * But we don't care, since "task_running()" will |
| * return false if the runqueue has changed and p |
| * is actually now running somewhere else! |
| */ |
| while (task_running(rq, p)) |
| cpu_relax(); |
| |
| /* |
| * Ok, time to look more closely! We need the rq |
| * lock now, to be *sure*. If we're wrong, we'll |
| * just go back and repeat. |
| */ |
| rq = task_rq_lock(p, &flags); |
| running = task_running(rq, p); |
| on_rq = p->se.on_rq; |
| task_rq_unlock(rq, &flags); |
| |
| /* |
| * Was it really running after all now that we |
| * checked with the proper locks actually held? |
| * |
| * Oops. Go back and try again.. |
| */ |
| if (unlikely(running)) { |
| cpu_relax(); |
| continue; |
| } |
| |
| /* |
| * It's not enough that it's not actively running, |
| * it must be off the runqueue _entirely_, and not |
| * preempted! |
| * |
| * So if it wa still runnable (but just not actively |
| * running right now), it's preempted, and we should |
| * yield - it could be a while. |
| */ |
| if (unlikely(on_rq)) { |
| schedule_timeout_uninterruptible(1); |
| continue; |
| } |
| |
| /* |
| * Ahh, all good. It wasn't running, and it wasn't |
| * runnable, which means that it will never become |
| * running in the future either. We're all done! |
| */ |
| break; |
| } |
| } |
| |
| /*** |
| * kick_process - kick a running thread to enter/exit the kernel |
| * @p: the to-be-kicked thread |
| * |
| * Cause a process which is running on another CPU to enter |
| * kernel-mode, without any delay. (to get signals handled.) |
| * |
| * NOTE: this function doesnt have to take the runqueue lock, |
| * because all it wants to ensure is that the remote task enters |
| * the kernel. If the IPI races and the task has been migrated |
| * to another CPU then no harm is done and the purpose has been |
| * achieved as well. |
| */ |
| void kick_process(struct task_struct *p) |
| { |
| int cpu; |
| |
| preempt_disable(); |
| cpu = task_cpu(p); |
| if ((cpu != smp_processor_id()) && task_curr(p)) |
| smp_send_reschedule(cpu); |
| preempt_enable(); |
| } |
| |
| /* |
| * Return a low guess at the load of a migration-source cpu weighted |
| * according to the scheduling class and "nice" value. |
| * |
| * We want to under-estimate the load of migration sources, to |
| * balance conservatively. |
| */ |
| static unsigned long source_load(int cpu, int type) |
| { |
| struct rq *rq = cpu_rq(cpu); |
| unsigned long total = weighted_cpuload(cpu); |
| |
| if (type == 0 || !sched_feat(LB_BIAS)) |
| return total; |
| |
| return min(rq->cpu_load[type-1], total); |
| } |
| |
| /* |
| * Return a high guess at the load of a migration-target cpu weighted |
| * according to the scheduling class and "nice" value. |
| */ |
| static unsigned long target_load(int cpu, int type) |
| { |
| struct rq *rq = cpu_rq(cpu); |
| unsigned long total = weighted_cpuload(cpu); |
| |
| if (type == 0 || !sched_feat(LB_BIAS)) |
| return total; |
| |
| return max(rq->cpu_load[type-1], total); |
| } |
| |
| /* |
| * find_idlest_group finds and returns the least busy CPU group within the |
| * domain. |
| */ |
| static struct sched_group * |
| find_idlest_group(struct sched_domain *sd, struct task_struct *p, int this_cpu) |
| { |
| struct sched_group *idlest = NULL, *this = NULL, *group = sd->groups; |
| unsigned long min_load = ULONG_MAX, this_load = 0; |
| int load_idx = sd->forkexec_idx; |
| int imbalance = 100 + (sd->imbalance_pct-100)/2; |
| |
| do { |
| unsigned long load, avg_load; |
| int local_group; |
| int i; |
| |
| /* Skip over this group if it has no CPUs allowed */ |
| if (!cpus_intersects(group->cpumask, p->cpus_allowed)) |
| continue; |
| |
| local_group = cpu_isset(this_cpu, group->cpumask); |
| |
| /* Tally up the load of all CPUs in the group */ |
| avg_load = 0; |
| |
| for_each_cpu_mask(i, group->cpumask) { |
| /* Bias balancing toward cpus of our domain */ |
| if (local_group) |
| load = source_load(i, load_idx); |
| else |
| load = target_load(i, load_idx); |
| |
| avg_load += load; |
| } |
| |
| /* Adjust by relative CPU power of the group */ |
| avg_load = sg_div_cpu_power(group, |
| avg_load * SCHED_LOAD_SCALE); |
| |
| if (local_group) { |
| this_load = avg_load; |
| this = group; |
| } else if (avg_load < min_load) { |
| min_load = avg_load; |
| idlest = group; |
| } |
| } while (group = group->next, group != sd->groups); |
| |
| if (!idlest || 100*this_load < imbalance*min_load) |
| return NULL; |
| return idlest; |
| } |
| |
| /* |
| * find_idlest_cpu - find the idlest cpu among the cpus in group. |
| */ |
| static int |
| find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu, |
| cpumask_t *tmp) |
| { |
| unsigned long load, min_load = ULONG_MAX; |
| int idlest = -1; |
| int i; |
| |
| /* Traverse only the allowed CPUs */ |
| cpus_and(*tmp, group->cpumask, p->cpus_allowed); |
| |
| for_each_cpu_mask(i, *tmp) { |
| load = weighted_cpuload(i); |
| |
| if (load < min_load || (load == min_load && i == this_cpu)) { |
| min_load = load; |
| idlest = i; |
| } |
| } |
| |
| return idlest; |
| } |
| |
| /* |
| * sched_balance_self: balance the current task (running on cpu) in domains |
| * that have the 'flag' flag set. In practice, this is SD_BALANCE_FORK and |
| * SD_BALANCE_EXEC. |
| * |
| * Balance, ie. select the least loaded group. |
| * |
| * Returns the target CPU number, or the same CPU if no balancing is needed. |
| * |
| * preempt must be disabled. |
| */ |
| static int sched_balance_self(int cpu, int flag) |
| { |
| struct task_struct *t = current; |
| struct sched_domain *tmp, *sd = NULL; |
| |
| for_each_domain(cpu, tmp) { |
| /* |
| * If power savings logic is enabled for a domain, stop there. |
| */ |
| if (tmp->flags & SD_POWERSAVINGS_BALANCE) |
| break; |
| if (tmp->flags & flag) |
| sd = tmp; |
| } |
| |
| if (sd) |
| update_shares(sd); |
| |
| while (sd) { |
| cpumask_t span, tmpmask; |
| struct sched_group *group; |
| int new_cpu, weight; |
| |
| if (!(sd->flags & flag)) { |
| sd = sd->child; |
| continue; |
| } |
| |
| span = sd->span; |
| group = find_idlest_group(sd, t, cpu); |
| if (!group) { |
| sd = sd->child; |
| continue; |
| } |
| |
| new_cpu = find_idlest_cpu(group, t, cpu, &tmpmask); |
| if (new_cpu == -1 || new_cpu == cpu) { |
| /* Now try balancing at a lower domain level of cpu */ |
| sd = sd->child; |
| continue; |
| } |
| |
| /* Now try balancing at a lower domain level of new_cpu */ |
| cpu = new_cpu; |
| sd = NULL; |
| weight = cpus_weight(span); |
| for_each_domain(cpu, tmp) { |
| if (weight <= cpus_weight(tmp->span)) |
| break; |
| if (tmp->flags & flag) |
| sd = tmp; |
| } |
| /* while loop will break here if sd == NULL */ |
| } |
| |
| return cpu; |
| } |
| |
| #endif /* CONFIG_SMP */ |
| |
| /*** |
| * try_to_wake_up - wake up a thread |
| * @p: the to-be-woken-up thread |
| * @state: the mask of task states that can be woken |
| * @sync: do a synchronous wakeup? |
| * |
| * Put it on the run-queue if it's not already there. The "current" |
| * thread is always on the run-queue (except when the actual |
| * re-schedule is in progress), and as such you're allowed to do |
| * the simpler "current->state = TASK_RUNNING" to mark yourself |
| * runnable without the overhead of this. |
| * |
| * returns failure only if the task is already active. |
| */ |
| static int try_to_wake_up(struct task_struct *p, unsigned int state, int sync) |
| { |
| int cpu, orig_cpu, this_cpu, success = 0; |
| unsigned long flags; |
| long old_state; |
| struct rq *rq; |
| |
| if (!sched_feat(SYNC_WAKEUPS)) |
| sync = 0; |
| |
| #ifdef CONFIG_SMP |
| if (sched_feat(LB_WAKEUP_UPDATE)) { |
| struct sched_domain *sd; |
| |
| this_cpu = raw_smp_processor_id(); |
| cpu = task_cpu(p); |
| |
| for_each_domain(this_cpu, sd) { |
| if (cpu_isset(cpu, sd->span)) { |
| update_shares(sd); |
| break; |
| } |
| } |
| } |
| #endif |
| |
| smp_wmb(); |
| rq = task_rq_lock(p, &flags); |
| old_state = p->state; |
| if (!(old_state & state)) |
| goto out; |
| |
| if (p->se.on_rq) |
| goto out_running; |
| |
| cpu = task_cpu(p); |
| orig_cpu = cpu; |
| this_cpu = smp_processor_id(); |
| |
| #ifdef CONFIG_SMP |
| if (unlikely(task_running(rq, p))) |
| goto out_activate; |
| |
| cpu = p->sched_class->select_task_rq(p, sync); |
| if (cpu != orig_cpu) { |
| set_task_cpu(p, cpu); |
| task_rq_unlock(rq, &flags); |
| /* might preempt at this point */ |
| rq = task_rq_lock(p, &flags); |
| old_state = p->state; |
| if (!(old_state & state)) |
| goto out; |
| if (p->se.on_rq) |
| goto out_running; |
| |
| this_cpu = smp_processor_id(); |
| cpu = task_cpu(p); |
| } |
| |
| #ifdef CONFIG_SCHEDSTATS |
| schedstat_inc(rq, ttwu_count); |
| if (cpu == this_cpu) |
| schedstat_inc(rq, ttwu_local); |
| else { |
| struct sched_domain *sd; |
| for_each_domain(this_cpu, sd) { |
| if (cpu_isset(cpu, sd->span)) { |
| schedstat_inc(sd, ttwu_wake_remote); |
| break; |
| } |
| } |
| } |
| #endif /* CONFIG_SCHEDSTATS */ |
| |
| out_activate: |
| #endif /* CONFIG_SMP */ |
| schedstat_inc(p, se.nr_wakeups); |
| if (sync) |
| schedstat_inc(p, se.nr_wakeups_sync); |
| if (orig_cpu != cpu) |
| schedstat_inc(p, se.nr_wakeups_migrate); |
| if (cpu == this_cpu) |
| schedstat_inc(p, se.nr_wakeups_local); |
| else |
| schedstat_inc(p, se.nr_wakeups_remote); |
| update_rq_clock(rq); |
| activate_task(rq, p, 1); |
| success = 1; |
| |
| out_running: |
| trace_mark(kernel_sched_wakeup, |
| "pid %d state %ld ## rq %p task %p rq->curr %p", |
| p->pid, p->state, rq, p, rq->curr); |
| check_preempt_curr(rq, p); |
| |
| p->state = TASK_RUNNING; |
| #ifdef CONFIG_SMP |
| if (p->sched_class->task_wake_up) |
| p->sched_class->task_wake_up(rq, p); |
| #endif |
| out: |
| current->se.last_wakeup = current->se.sum_exec_runtime; |
| |
| task_rq_unlock(rq, &flags); |
| |
| return success; |
| } |
| |
| int wake_up_process(struct task_struct *p) |
| { |
| return try_to_wake_up(p, TASK_ALL, 0); |
| } |
| EXPORT_SYMBOL(wake_up_process); |
| |
| int wake_up_state(struct task_struct *p, unsigned int state) |
| { |
| return try_to_wake_up(p, state, 0); |
| } |
| |
| /* |
| * Perform scheduler related setup for a newly forked process p. |
| * p is forked by current. |
| * |
| * __sched_fork() is basic setup used by init_idle() too: |
| */ |
| static void __sched_fork(struct task_struct *p) |
| { |
| p->se.exec_start = 0; |
| p->se.sum_exec_runtime = 0; |
| p->se.prev_sum_exec_runtime = 0; |
| p->se.last_wakeup = 0; |
| p->se.avg_overlap = 0; |
| |
| #ifdef CONFIG_SCHEDSTATS |
| p->se.wait_start = 0; |
| p->se.sum_sleep_runtime = 0; |
| p->se.sleep_start = 0; |
| p->se.block_start = 0; |
| p->se.sleep_max = 0; |
| p->se.block_max = 0; |
| p->se.exec_max = 0; |
| p->se.slice_max = 0; |
| p->se.wait_max = 0; |
| #endif |
| |
| INIT_LIST_HEAD(&p->rt.run_list); |
| p->se.on_rq = 0; |
| INIT_LIST_HEAD(&p->se.group_node); |
| |
| #ifdef CONFIG_PREEMPT_NOTIFIERS |
| INIT_HLIST_HEAD(&p->preempt_notifiers); |
| #endif |
| |
| /* |
| * We mark the process as running here, but have not actually |
| * inserted it onto the runqueue yet. This guarantees that |
| * nobody will actually run it, and a signal or other external |
| * event cannot wake it up and insert it on the runqueue either. |
| */ |
| p->state = TASK_RUNNING; |
| } |
| |
| /* |
| * fork()/clone()-time setup: |
| */ |
| void sched_fork(struct task_struct *p, int clone_flags) |
| { |
| int cpu = get_cpu(); |
| |
| __sched_fork(p); |
| |
| #ifdef CONFIG_SMP |
| cpu = sched_balance_self(cpu, SD_BALANCE_FORK); |
| #endif |
| set_task_cpu(p, cpu); |
| |
| /* |
| * Make sure we do not leak PI boosting priority to the child: |
| */ |
| p->prio = current->normal_prio; |
| if (!rt_prio(p->prio)) |
| p->sched_class = &fair_sched_class; |
| |
| #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) |
| if (likely(sched_info_on())) |
| memset(&p->sched_info, 0, sizeof(p->sched_info)); |
| #endif |
| #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
| p->oncpu = 0; |
| #endif |
| #ifdef CONFIG_PREEMPT |
| /* Want to start with kernel preemption disabled. */ |
| task_thread_info(p)->preempt_count = 1; |
| #endif |
| put_cpu(); |
| } |
| |
| /* |
| * wake_up_new_task - wake up a newly created task for the first time. |
| * |
| * This function will do some initial scheduler statistics housekeeping |
| * that must be done for every newly created context, then puts the task |
| * on the runqueue and wakes it. |
| */ |
| void wake_up_new_task(struct task_struct *p, unsigned long clone_flags) |
| { |
| unsigned long flags; |
| struct rq *rq; |
| |
| rq = task_rq_lock(p, &flags); |
| BUG_ON(p->state != TASK_RUNNING); |
| update_rq_clock(rq); |
| |
| p->prio = effective_prio(p); |
| |
| if (!p->sched_class->task_new || !current->se.on_rq) { |
| activate_task(rq, p, 0); |
| } else { |
| /* |
| * Let the scheduling class do new task startup |
| * management (if any): |
| */ |
| p->sched_class->task_new(rq, p); |
| inc_nr_running(rq); |
| } |
| trace_mark(kernel_sched_wakeup_new, |
| "pid %d state %ld ## rq %p task %p rq->curr %p", |
| p->pid, p->state, rq, p, rq->curr); |
| check_preempt_curr(rq, p); |
| #ifdef CONFIG_SMP |
| if (p->sched_class->task_wake_up) |
| p->sched_class->task_wake_up(rq, p); |
| #endif |
| task_rq_unlock(rq, &flags); |
| } |
| |
| #ifdef CONFIG_PREEMPT_NOTIFIERS |
| |
| /** |
| * preempt_notifier_register - tell me when current is being being preempted & rescheduled |
| * @notifier: notifier struct to register |
| */ |
| void preempt_notifier_register(struct preempt_notifier *notifier) |
| { |
| hlist_add_head(¬ifier->link, ¤t->preempt_notifiers); |
| } |
| EXPORT_SYMBOL_GPL(preempt_notifier_register); |
| |
| /** |
| * preempt_notifier_unregister - no longer interested in preemption notifications |
| * @notifier: notifier struct to unregister |
| * |
| * This is safe to call from within a preemption notifier. |
| */ |
| void preempt_notifier_unregister(struct preempt_notifier *notifier) |
| { |
| hlist_del(¬ifier->link); |
| } |
| EXPORT_SYMBOL_GPL(preempt_notifier_unregister); |
| |
| static void fire_sched_in_preempt_notifiers(struct task_struct *curr) |
| { |
| struct preempt_notifier *notifier; |
| struct hlist_node *node; |
| |
| hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) |
| notifier->ops->sched_in(notifier, raw_smp_processor_id()); |
| } |
| |
| static void |
| fire_sched_out_preempt_notifiers(struct task_struct *curr, |
| struct task_struct *next) |
| { |
| struct preempt_notifier *notifier; |
| struct hlist_node *node; |
| |
| hlist_for_each_entry(notifier, node, &curr->preempt_notifiers, link) |
| notifier->ops->sched_out(notifier, next); |
| } |
| |
| #else /* !CONFIG_PREEMPT_NOTIFIERS */ |
| |
| static void fire_sched_in_preempt_notifiers(struct task_struct *curr) |
| { |
| } |
| |
| static void |
| fire_sched_out_preempt_notifiers(struct task_struct *curr, |
| struct task_struct *next) |
| { |
| } |
| |
| #endif /* CONFIG_PREEMPT_NOTIFIERS */ |
| |
| /** |
| * prepare_task_switch - prepare to switch tasks |
| * @rq: the runqueue preparing to switch |
| * @prev: the current task that is being switched out |
| * @next: the task we are going to switch to. |
| * |
| * This is called with the rq lock held and interrupts off. It must |
| * be paired with a subsequent finish_task_switch after the context |
| * switch. |
| * |
| * prepare_task_switch sets up locking and calls architecture specific |
| * hooks. |
| */ |
| static inline void |
| prepare_task_switch(struct rq *rq, struct task_struct *prev, |
| struct task_struct *next) |
| { |
| fire_sched_out_preempt_notifiers(prev, next); |
| prepare_lock_switch(rq, next); |
| prepare_arch_switch(next); |
| } |
| |
| /** |
| * finish_task_switch - clean up after a task-switch |
| * @rq: runqueue associated with task-switch |
| * @prev: the thread we just switched away from. |
| * |
| * finish_task_switch must be called after the context switch, paired |
| * with a prepare_task_switch call before the context switch. |
| * finish_task_switch will reconcile locking set up by prepare_task_switch, |
| * and do any other architecture-specific cleanup actions. |
| * |
| * Note that we may have delayed dropping an mm in context_switch(). If |
| * so, we finish that here outside of the runqueue lock. (Doing it |
| * with the lock held can cause deadlocks; see schedule() for |
| * details.) |
| */ |
| static void finish_task_switch(struct rq *rq, struct task_struct *prev) |
| __releases(rq->lock) |
| { |
| struct mm_struct *mm = rq->prev_mm; |
| long prev_state; |
| |
| rq->prev_mm = NULL; |
| |
| /* |
| * A task struct has one reference for the use as "current". |
| * If a task dies, then it sets TASK_DEAD in tsk->state and calls |
| * schedule one last time. The schedule call will never return, and |
| * the scheduled task must drop that reference. |
| * The test for TASK_DEAD must occur while the runqueue locks are |
| * still held, otherwise prev could be scheduled on another cpu, die |
| * there before we look at prev->state, and then the reference would |
| * be dropped twice. |
| * Manfred Spraul <manfred@colorfullife.com> |
| */ |
| prev_state = prev->state; |
| finish_arch_switch(prev); |
| finish_lock_switch(rq, prev); |
| #ifdef CONFIG_SMP |
| if (current->sched_class->post_schedule) |
| current->sched_class->post_schedule(rq); |
| #endif |
| |
| fire_sched_in_preempt_notifiers(current); |
| if (mm) |
| mmdrop(mm); |
| if (unlikely(prev_state == TASK_DEAD)) { |
| /* |
| * Remove function-return probe instances associated with this |
| * task and put them back on the free list. |
| */ |
| kprobe_flush_task(prev); |
| put_task_struct(prev); |
| } |
| } |
| |
| /** |
| * schedule_tail - first thing a freshly forked thread must call. |
| * @prev: the thread we just switched away from. |
| */ |
| asmlinkage void schedule_tail(struct task_struct *prev) |
| __releases(rq->lock) |
| { |
| struct rq *rq = this_rq(); |
| |
| finish_task_switch(rq, prev); |
| #ifdef __ARCH_WANT_UNLOCKED_CTXSW |
| /* In this case, finish_task_switch does not reenable preemption */ |
| preempt_enable(); |
| #endif |
| if (current->set_child_tid) |
| put_user(task_pid_vnr(current), current->set_child_tid); |
| } |
| |
| /* |
| * context_switch - switch to the new MM and the new |
| * thread's register state. |
| */ |
| static inline void |
| context_switch(struct rq *rq, struct task_struct *prev, |
| struct task_struct *next) |
| { |
| struct mm_struct *mm, *oldmm; |
| |
| prepare_task_switch(rq, prev, next); |
| trace_mark(kernel_sched_schedule, |
| "prev_pid %d next_pid %d prev_state %ld " |
| "## rq %p prev %p next %p", |
| prev->pid, next->pid, prev->state, |
| rq, prev, next); |
| mm = next->mm; |
| oldmm = prev->active_mm; |
| /* |
| * For paravirt, this is coupled with an exit in switch_to to |
| * combine the page table reload and the switch backend into |
| * one hypercall. |
| */ |
| arch_enter_lazy_cpu_mode(); |
| |
| if (unlikely(!mm)) { |
| next->active_mm = oldmm; |
| atomic_inc(&oldmm->mm_count); |
| enter_lazy_tlb(oldmm, next); |
| } else |
| switch_mm(oldmm, mm, next); |
| |
| if (unlikely(!prev->mm)) { |
| prev->active_mm = NULL; |
| rq->prev_mm = oldmm; |
| } |
| /* |
| * Since the runqueue lock will be released by the next |
| * task (which is an invalid locking op but in the case |
| * of the scheduler it's an obvious special-case), so we |
| * do an early lockdep release here: |
| */ |
| #ifndef __ARCH_WANT_UNLOCKED_CTXSW |
| spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
| #endif |
| |
| /* Here we just switch the register state and the stack. */ |
| switch_to(prev, next, prev); |
| |
| barrier(); |
| /* |
| * this_rq must be evaluated again because prev may have moved |
| * CPUs since it called schedule(), thus the 'rq' on its stack |
| * frame will be invalid. |
| */ |
| finish_task_switch(this_rq(), prev); |
| } |
| |
| /* |
| * nr_running, nr_uninterruptible and nr_context_switches: |
| * |
| * externally visible scheduler statistics: current number of runnable |
| * threads, current number of uninterruptible-sleeping threads, total |
| * number of context switches performed since bootup. |
| */ |
| unsigned long nr_running(void) |
| { |
| unsigned long i, sum = 0; |
| |
| for_each_online_cpu(i) |
| sum += cpu_rq(i)->nr_running; |
| |
| return sum; |
| } |
| |
| unsigned long nr_uninterruptible(void) |
| { |
| unsigned long i, sum = 0; |
| |
| for_each_possible_cpu(i) |
| sum += cpu_rq(i)->nr_uninterruptible; |
| |
| /* |
| * Since we read the counters lockless, it might be slightly |
| * inaccurate. Do not allow it to go below zero though: |
| */ |
| if (unlikely((long)sum < 0)) |
| sum = 0; |
| |
| return sum; |
| } |
| |
| unsigned long long nr_context_switches(void) |
| { |
| int i; |
| unsigned long long sum = 0; |
| |
| for_each_possible_cpu(i) |
| sum += cpu_rq(i)->nr_switches; |
| |
| return sum; |
| } |
| |
| unsigned long nr_iowait(void) |
| { |
| unsigned long i, sum = 0; |
| |
| for_each_possible_cpu(i) |
| sum += atomic_read(&cpu_rq(i)->nr_iowait); |
| |
| return sum; |
| } |
| |
| unsigned long nr_active(void) |
| { |
| unsigned long i, running = 0, uninterruptible = 0; |
| |
| for_each_online_cpu(i) { |
| running += cpu_rq(i)->nr_running; |
| uninterruptible += cpu_rq(i)->nr_uninterruptible; |
| } |
| |
| if (unlikely((long)uninterruptible < 0)) |
| uninterruptible = 0; |
| |
| return running + uninterruptible; |
| } |
| |
| /* |
| * Update rq->cpu_load[] statistics. This function is usually called every |
| * scheduler tick (TICK_NSEC). |
| */ |
| static void update_cpu_load(struct rq *this_rq) |
| { |
| unsigned long this_load = this_rq->load.weight; |
| int i, scale; |
| |
| this_rq->nr_load_updates++; |
| |
| /* Update our load: */ |
| for (i = 0, scale = 1; i < CPU_LOAD_IDX_MAX; i++, scale += scale) { |
| unsigned long old_load, new_load; |
| |
| /* scale is effectively 1 << i now, and >> i divides by scale */ |
| |
| old_load = this_rq->cpu_load[i]; |
| new_load = this_load; |
| /* |
| * Round up the averaging division if load is increasing. This |
| * prevents us from getting stuck on 9 if the load is 10, for |
| * example. |
| */ |
| if (new_load > old_load) |
| new_load += scale-1; |
| this_rq->cpu_load[i] = (old_load*(scale-1) + new_load) >> i; |
| } |
| } |
| |
| #ifdef CONFIG_SMP |
| |
| /* |
| * double_rq_lock - safely lock two runqueues |
| * |
| * Note this does not disable interrupts like task_rq_lock, |
| * you need to do so manually before calling. |
| */ |
| static void double_rq_lock(struct rq *rq1, struct rq *rq2) |
| __acquires(rq1->lock) |
| __acquires(rq2->lock) |
| { |
| BUG_ON(!irqs_disabled()); |
| if (rq1 == rq2) { |
| spin_lock(&rq1->lock); |
| __acquire(rq2->lock); /* Fake it out ;) */ |
| } else { |
| if (rq1 < rq2) { |
| spin_lock(&rq1->lock); |
| spin_lock(&rq2->lock); |
| } else { |
| spin_lock(&rq2->lock); |
| spin_lock(&rq1->lock); |
| } |
| } |
| update_rq_clock(rq1); |
| update_rq_clock(rq2); |
| } |
| |
| /* |
| * double_rq_unlock - safely unlock two runqueues |
| * |
| * Note this does not restore interrupts like task_rq_unlock, |
| * you need to do so manually after calling. |
| */ |
| static void double_rq_unlock(struct rq *rq1, struct rq *rq2) |
| __releases(rq1->lock) |
| __releases(rq2->lock) |
| { |
| spin_unlock(&rq1->lock); |
| if (rq1 != rq2) |
| spin_unlock(&rq2->lock); |
| else |
| __release(rq2->lock); |
| } |
| |
| /* |
| * double_lock_balance - lock the busiest runqueue, this_rq is locked already. |
| */ |
| static int double_lock_balance(struct rq *this_rq, struct rq *busiest) |
| __releases(this_rq->lock) |
| __acquires(busiest->lock) |
| __acquires(this_rq->lock) |
| { |
| int ret = 0; |
| |
| if (unlikely(!irqs_disabled())) { |
| /* printk() doesn't work good under rq->lock */ |
| spin_unlock(&this_rq->lock); |
| BUG_ON(1); |
| } |
| if (unlikely(!spin_trylock(&busiest->lock))) { |
| if (busiest < this_rq) { |
| spin_unlock(&this_rq->lock); |
| spin_lock(&busiest->lock); |
| spin_lock(&this_rq->lock); |
| ret = 1; |
| } else |
| spin_lock(&busiest->lock); |
| } |
| return ret; |
| } |
| |
| /* |
| * If dest_cpu is allowed for this process, migrate the task to it. |
| * This is accomplished by forcing the cpu_allowed mask to only |
| * allow dest_cpu, which will force the cpu onto dest_cpu. Then |
| * the cpu_allowed mask is restored. |
| */ |
| static void sched_migrate_task(struct task_struct *p, int dest_cpu) |
| { |
| struct migration_req req; |
| unsigned long flags; |
| struct rq *rq; |
| |
| rq = task_rq_lock(p, &flags); |
| if (!cpu_isset(dest_cpu, p->cpus_allowed) |
| || unlikely(cpu_is_offline(dest_cpu))) |
| goto out; |
| |
| /* force the process onto the specified CPU */ |
| if (migrate_task(p, dest_cpu, &req)) { |
| /* Need to wait for migration thread (might exit: take ref). */ |
| struct task_struct *mt = rq->migration_thread; |
| |
| get_task_struct(mt); |
| task_rq_unlock(rq, &flags); |
| wake_up_process(mt); |
| put_task_struct(mt); |
| wait_for_completion(&req.done); |
| |
| return; |
| } |
| out: |
| task_rq_unlock(rq, &flags); |
| } |
| |
| /* |
| * sched_exec - execve() is a valuable balancing opportunity, because at |
| * this point the task has the smallest effective memory and cache footprint. |
| */ |
| void sched_exec(void) |
| { |
| int new_cpu, this_cpu = get_cpu(); |
| new_cpu = sched_balance_self(this_cpu, SD_BALANCE_EXEC); |
| put_cpu(); |
| if (new_cpu != this_cpu) |
| sched_migrate_task(current, new_cpu); |
| } |
| |
| /* |
| * pull_task - move a task from a remote runqueue to the local runqueue. |
| * Both runqueues must be locked. |
| */ |
| static void pull_task(struct rq *src_rq, struct task_struct *p, |
| struct rq *this_rq, int this_cpu) |
| { |
| deactivate_task(src_rq, p, 0); |
| set_task_cpu(p, this_cpu); |
| activate_task(this_rq, p, 0); |
| /* |
| * Note that idle threads have a prio of MAX_PRIO, for this test |
| * to be always true for them. |
| */ |
| check_preempt_curr(this_rq, p); |
| } |
| |
| /* |
| * can_migrate_task - may task p from runqueue rq be migrated to this_cpu? |
| */ |
| static |
| int can_migrate_task(struct task_struct *p, struct rq *rq, int this_cpu, |
| struct sched_domain *sd, enum cpu_idle_type idle, |
| int *all_pinned) |
| { |
| /* |
| * We do not migrate tasks that are: |
| * 1) running (obviously), or |
| * 2) cannot be migrated to this CPU due to cpus_allowed, or |
| * 3) are cache-hot on their current CPU. |
| */ |
| if (!cpu_isset(this_cpu, p->cpus_allowed)) { |
| schedstat_inc(p, se.nr_failed_migrations_affine); |
| return 0; |
| } |
| *all_pinned = 0; |
| |
| if (task_running(rq, p)) { |
| schedstat_inc(p, se.nr_failed_migrations_running); |
| return 0; |
| } |
| |
| /* |
| * Aggressive migration if: |
| * 1) task is cache cold, or |
| * 2) too many balance attempts have failed. |
| */ |
| |
| if (!task_hot(p, rq->clock, sd) || |
| sd->nr_balance_failed > sd->cache_nice_tries) { |
| #ifdef CONFIG_SCHEDSTATS |
| if (task_hot(p, rq->clock, sd)) { |
| schedstat_inc(sd, lb_hot_gained[idle]); |
| schedstat_inc(p, se.nr_forced_migrations); |
| } |
| #endif |
| return 1; |
| } |
| |
| if (task_hot(p, rq->clock, sd)) { |
| schedstat_inc(p, se.nr_failed_migrations_hot); |
| return 0; |
| } |
| return 1; |
| } |
| |
| static unsigned long |
| balance_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, |
| unsigned long max_load_move, struct sched_domain *sd, |
| enum cpu_idle_type idle, int *all_pinned, |
| int *this_best_prio, struct rq_iterator *iterator) |
| { |
| int loops = 0, pulled = 0, pinned = 0; |
| struct task_struct *p; |
| long rem_load_move = max_load_move; |
| |
| if (max_load_move == 0) |
| goto out; |
| |
| pinned = 1; |
| |
| /* |
| * Start the load-balancing iterator: |
| */ |
| p = iterator->start(iterator->arg); |
| next: |
| if (!p || loops++ > sysctl_sched_nr_migrate) |
| goto out; |
| |
| if ((p->se.load.weight >> 1) > rem_load_move || |
| !can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { |
| p = iterator->next(iterator->arg); |
| goto next; |
| } |
| |
| pull_task(busiest, p, this_rq, this_cpu); |
| pulled++; |
| rem_load_move -= p->se.load.weight; |
| |
| /* |
| * We only want to steal up to the prescribed amount of weighted load. |
| */ |
| if (rem_load_move > 0) { |
| if (p->prio < *this_best_prio) |
| *this_best_prio = p->prio; |
| p = iterator->next(iterator->arg); |
| goto next; |
| } |
| out: |
| /* |
| * Right now, this is one of only two places pull_task() is called, |
| * so we can safely collect pull_task() stats here rather than |
| * inside pull_task(). |
| */ |
| schedstat_add(sd, lb_gained[idle], pulled); |
| |
| if (all_pinned) |
| *all_pinned = pinned; |
| |
| return max_load_move - rem_load_move; |
| } |
| |
| /* |
| * move_tasks tries to move up to max_load_move weighted load from busiest to |
| * this_rq, as part of a balancing operation within domain "sd". |
| * Returns 1 if successful and 0 otherwise. |
| * |
| * Called with both runqueues locked. |
| */ |
| static int move_tasks(struct rq *this_rq, int this_cpu, struct rq *busiest, |
| unsigned long max_load_move, |
| struct sched_domain *sd, enum cpu_idle_type idle, |
| int *all_pinned) |
| { |
| const struct sched_class *class = sched_class_highest; |
| unsigned long total_load_moved = 0; |
| int this_best_prio = this_rq->curr->prio; |
| |
| do { |
| total_load_moved += |
| class->load_balance(this_rq, this_cpu, busiest, |
| max_load_move - total_load_moved, |
| sd, idle, all_pinned, &this_best_prio); |
| class = class->next; |
| |
| if (idle == CPU_NEWLY_IDLE && this_rq->nr_running) |
| break; |
| |
| } while (class && max_load_move > total_load_moved); |
| |
| return total_load_moved > 0; |
| } |
| |
| static int |
| iter_move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, |
| struct sched_domain *sd, enum cpu_idle_type idle, |
| struct rq_iterator *iterator) |
| { |
| struct task_struct *p = iterator->start(iterator->arg); |
| int pinned = 0; |
| |
| while (p) { |
| if (can_migrate_task(p, busiest, this_cpu, sd, idle, &pinned)) { |
| pull_task(busiest, p, this_rq, this_cpu); |
| /* |
| * Right now, this is only the second place pull_task() |
| * is called, so we can safely collect pull_task() |
| * stats here rather than inside pull_task(). |
| */ |
| schedstat_inc(sd, lb_gained[idle]); |
| |
| return 1; |
| } |
| p = iterator->next(iterator->arg); |
| } |
| |
| return 0; |
| } |
| |
| /* |
| * move_one_task tries to move exactly one task from busiest to this_rq, as |
| * part of active balancing operations within "domain". |
| * Returns 1 if successful and 0 otherwise. |
| * |
| * Called with both runqueues locked. |
| */ |
| static int move_one_task(struct rq *this_rq, int this_cpu, struct rq *busiest, |
| struct sched_domain *sd, enum cpu_idle_type idle) |
| { |
| const struct sched_class *class; |
| |
| for (class = sched_class_highest; class; class = class->next) |
| if (class->move_one_task(this_rq, this_cpu, busiest, sd, idle)) |
| return 1; |
| |
| return 0; |
| } |
| |
| /* |
| * find_busiest_group finds and returns the busiest CPU group within the |
| * domain. It calculates and returns the amount of weighted load which |
| * should be moved to restore balance via the imbalance parameter. |
| */ |
| static struct sched_group * |
| find_busiest_group(struct sched_domain *sd, int this_cpu, |
| unsigned long *imbalance, enum cpu_idle_type idle, |
| int *sd_idle, const cpumask_t *cpus, int *balance) |
| { |
| struct sched_group *busiest = NULL, *this = NULL, *group = sd->groups; |
| unsigned long max_load, avg_load, total_load, this_load, total_pwr; |
| unsigned long max_pull; |
| unsigned long busiest_load_per_task, busiest_nr_running; |
| unsigned long this_load_per_task, this_nr_running; |
| int load_idx, group_imb = 0; |
| #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
| int power_savings_balance = 1; |
| unsigned long leader_nr_running = 0, min_load_per_task = 0; |
| unsigned long min_nr_running = ULONG_MAX; |
| struct sched_group *group_min = NULL, *group_leader = NULL; |
| #endif |
| |
| max_load = this_load = total_load = total_pwr = 0; |
| busiest_load_per_task = busiest_nr_running = 0; |
| this_load_per_task = this_nr_running = 0; |
| |
| if (idle == CPU_NOT_IDLE) |
| load_idx = sd->busy_idx; |
| else if (idle == CPU_NEWLY_IDLE) |
| load_idx = sd->newidle_idx; |
| else |
| load_idx = sd->idle_idx; |
| |
| do { |
| unsigned long load, group_capacity, max_cpu_load, min_cpu_load; |
| int local_group; |
| int i; |
| int __group_imb = 0; |
| unsigned int balance_cpu = -1, first_idle_cpu = 0; |
| unsigned long sum_nr_running, sum_weighted_load; |
| unsigned long sum_avg_load_per_task; |
| unsigned long avg_load_per_task; |
| |
| local_group = cpu_isset(this_cpu, group->cpumask); |
| |
| if (local_group) |
| balance_cpu = first_cpu(group->cpumask); |
| |
| /* Tally up the load of all CPUs in the group */ |
| sum_weighted_load = sum_nr_running = avg_load = 0; |
| sum_avg_load_per_task = avg_load_per_task = 0; |
| |
| max_cpu_load = 0; |
| min_cpu_load = ~0UL; |
| |
| for_each_cpu_mask(i, group->cpumask) { |
| struct rq *rq; |
| |
| if (!cpu_isset(i, *cpus)) |
| continue; |
| |
| rq = cpu_rq(i); |
| |
| if (*sd_idle && rq->nr_running) |
| *sd_idle = 0; |
| |
| /* Bias balancing toward cpus of our domain */ |
| if (local_group) { |
| if (idle_cpu(i) && !first_idle_cpu) { |
| first_idle_cpu = 1; |
| balance_cpu = i; |
| } |
| |
| load = target_load(i, load_idx); |
| } else { |
| load = source_load(i, load_idx); |
| if (load > max_cpu_load) |
| max_cpu_load = load; |
| if (min_cpu_load > load) |
| min_cpu_load = load; |
| } |
| |
| avg_load += load; |
| sum_nr_running += rq->nr_running; |
| sum_weighted_load += weighted_cpuload(i); |
| |
| sum_avg_load_per_task += cpu_avg_load_per_task(i); |
| } |
| |
| /* |
| * First idle cpu or the first cpu(busiest) in this sched group |
| * is eligible for doing load balancing at this and above |
| * domains. In the newly idle case, we will allow all the cpu's |
| * to do the newly idle load balance. |
| */ |
| if (idle != CPU_NEWLY_IDLE && local_group && |
| balance_cpu != this_cpu && balance) { |
| *balance = 0; |
| goto ret; |
| } |
| |
| total_load += avg_load; |
| total_pwr += group->__cpu_power; |
| |
| /* Adjust by relative CPU power of the group */ |
| avg_load = sg_div_cpu_power(group, |
| avg_load * SCHED_LOAD_SCALE); |
| |
| |
| /* |
| * Consider the group unbalanced when the imbalance is larger |
| * than the average weight of two tasks. |
| * |
| * APZ: with cgroup the avg task weight can vary wildly and |
| * might not be a suitable number - should we keep a |
| * normalized nr_running number somewhere that negates |
| * the hierarchy? |
| */ |
| avg_load_per_task = sg_div_cpu_power(group, |
| sum_avg_load_per_task * SCHED_LOAD_SCALE); |
| |
| if ((max_cpu_load - min_cpu_load) > 2*avg_load_per_task) |
| __group_imb = 1; |
| |
| group_capacity = group->__cpu_power / SCHED_LOAD_SCALE; |
| |
| if (local_group) { |
| this_load = avg_load; |
| this = group; |
| this_nr_running = sum_nr_running; |
| this_load_per_task = sum_weighted_load; |
| } else if (avg_load > max_load && |
| (sum_nr_running > group_capacity || __group_imb)) { |
| max_load = avg_load; |
| busiest = group; |
| busiest_nr_running = sum_nr_running; |
| busiest_load_per_task = sum_weighted_load; |
| group_imb = __group_imb; |
| } |
| |
| #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
| /* |
| * Busy processors will not participate in power savings |
| * balance. |
| */ |
| if (idle == CPU_NOT_IDLE || |
| !(sd->flags & SD_POWERSAVINGS_BALANCE)) |
| goto group_next; |
| |
| /* |
| * If the local group is idle or completely loaded |
| * no need to do power savings balance at this domain |
| */ |
| if (local_group && (this_nr_running >= group_capacity || |
| !this_nr_running)) |
| power_savings_balance = 0; |
| |
| /* |
| * If a group is already running at full capacity or idle, |
| * don't include that group in power savings calculations |
| */ |
| if (!power_savings_balance || sum_nr_running >= group_capacity |
| || !sum_nr_running) |
| goto group_next; |
| |
| /* |
| * Calculate the group which has the least non-idle load. |
| * This is the group from where we need to pick up the load |
| * for saving power |
| */ |
| if ((sum_nr_running < min_nr_running) || |
| (sum_nr_running == min_nr_running && |
| first_cpu(group->cpumask) < |
| first_cpu(group_min->cpumask))) { |
| group_min = group; |
| min_nr_running = sum_nr_running; |
| min_load_per_task = sum_weighted_load / |
| sum_nr_running; |
| } |
| |
| /* |
| * Calculate the group which is almost near its |
| * capacity but still has some space to pick up some load |
| * from other group and save more power |
| */ |
| if (sum_nr_running <= group_capacity - 1) { |
| if (sum_nr_running > leader_nr_running || |
| (sum_nr_running == leader_nr_running && |
| first_cpu(group->cpumask) > |
| first_cpu(group_leader->cpumask))) { |
| group_leader = group; |
| leader_nr_running = sum_nr_running; |
| } |
| } |
| group_next: |
| #endif |
| group = group->next; |
| } while (group != sd->groups); |
| |
| if (!busiest || this_load >= max_load || busiest_nr_running == 0) |
| goto out_balanced; |
| |
| avg_load = (SCHED_LOAD_SCALE * total_load) / total_pwr; |
| |
| if (this_load >= avg_load || |
| 100*max_load <= sd->imbalance_pct*this_load) |
| goto out_balanced; |
| |
| busiest_load_per_task /= busiest_nr_running; |
| if (group_imb) |
| busiest_load_per_task = min(busiest_load_per_task, avg_load); |
| |
| /* |
| * We're trying to get all the cpus to the average_load, so we don't |
| * want to push ourselves above the average load, nor do we wish to |
| * reduce the max loaded cpu below the average load, as either of these |
| * actions would just result in more rebalancing later, and ping-pong |
| * tasks around. Thus we look for the minimum possible imbalance. |
| * Negative imbalances (*we* are more loaded than anyone else) will |
| * be counted as no imbalance for these purposes -- we can't fix that |
| * by pulling tasks to us. Be careful of negative numbers as they'll |
| * appear as very large values with unsigned longs. |
| */ |
| if (max_load <= busiest_load_per_task) |
| goto out_balanced; |
| |
| /* |
| * In the presence of smp nice balancing, certain scenarios can have |
| * max load less than avg load(as we skip the groups at or below |
| * its cpu_power, while calculating max_load..) |
| */ |
| if (max_load < avg_load) { |
| *imbalance = 0; |
| goto small_imbalance; |
| } |
| |
| /* Don't want to pull so many tasks that a group would go idle */ |
| max_pull = min(max_load - avg_load, max_load - busiest_load_per_task); |
| |
| /* How much load to actually move to equalise the imbalance */ |
| *imbalance = min(max_pull * busiest->__cpu_power, |
| (avg_load - this_load) * this->__cpu_power) |
| / SCHED_LOAD_SCALE; |
| |
| /* |
| * if *imbalance is less than the average load per runnable task |
| * there is no gaurantee that any tasks will be moved so we'll have |
| * a think about bumping its value to force at least one task to be |
| * moved |
| */ |
| if (*imbalance < busiest_load_per_task) { |
| unsigned long tmp, pwr_now, pwr_move; |
| unsigned int imbn; |
| |
| small_imbalance: |
| pwr_move = pwr_now = 0; |
| imbn = 2; |
| if (this_nr_running) { |
| this_load_per_task /= this_nr_running; |
| if (busiest_load_per_task > this_load_per_task) |
| imbn = 1; |
| } else |
| this_load_per_task = cpu_avg_load_per_task(this_cpu); |
| |
| if (max_load - this_load + 2*busiest_load_per_task >= |
| busiest_load_per_task * imbn) { |
| *imbalance = busiest_load_per_task; |
| return busiest; |
| } |
| |
| /* |
| * OK, we don't have enough imbalance to justify moving tasks, |
| * however we may be able to increase total CPU power used by |
| * moving them. |
| */ |
| |
| pwr_now += busiest->__cpu_power * |
| min(busiest_load_per_task, max_load); |
| pwr_now += this->__cpu_power * |
| min(this_load_per_task, this_load); |
| pwr_now /= SCHED_LOAD_SCALE; |
| |
| /* Amount of load we'd subtract */ |
| tmp = sg_div_cpu_power(busiest, |
| busiest_load_per_task * SCHED_LOAD_SCALE); |
| if (max_load > tmp) |
| pwr_move += busiest->__cpu_power * |
| min(busiest_load_per_task, max_load - tmp); |
| |
| /* Amount of load we'd add */ |
| if (max_load * busiest->__cpu_power < |
| busiest_load_per_task * SCHED_LOAD_SCALE) |
| tmp = sg_div_cpu_power(this, |
| max_load * busiest->__cpu_power); |
| else |
| tmp = sg_div_cpu_power(this, |
| busiest_load_per_task * SCHED_LOAD_SCALE); |
| pwr_move += this->__cpu_power * |
| min(this_load_per_task, this_load + tmp); |
| pwr_move /= SCHED_LOAD_SCALE; |
| |
| /* Move if we gain throughput */ |
| if (pwr_move > pwr_now) |
| *imbalance = busiest_load_per_task; |
| } |
| |
| return busiest; |
| |
| out_balanced: |
| #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
| if (idle == CPU_NOT_IDLE || !(sd->flags & SD_POWERSAVINGS_BALANCE)) |
| goto ret; |
| |
| if (this == group_leader && group_leader != group_min) { |
| *imbalance = min_load_per_task; |
| return group_min; |
| } |
| #endif |
| ret: |
| *imbalance = 0; |
| return NULL; |
| } |
| |
| /* |
| * find_busiest_queue - find the busiest runqueue among the cpus in group. |
| */ |
| static struct rq * |
| find_busiest_queue(struct sched_group *group, enum cpu_idle_type idle, |
| unsigned long imbalance, const cpumask_t *cpus) |
| { |
| struct rq *busiest = NULL, *rq; |
| unsigned long max_load = 0; |
| int i; |
| |
| for_each_cpu_mask(i, group->cpumask) { |
| unsigned long wl; |
| |
| if (!cpu_isset(i, *cpus)) |
| continue; |
| |
| rq = cpu_rq(i); |
| wl = weighted_cpuload(i); |
| |
| if (rq->nr_running == 1 && wl > imbalance) |
| continue; |
| |
| if (wl > max_load) { |
| max_load = wl; |
| busiest = rq; |
| } |
| } |
| |
| return busiest; |
| } |
| |
| /* |
| * Max backoff if we encounter pinned tasks. Pretty arbitrary value, but |
| * so long as it is large enough. |
| */ |
| #define MAX_PINNED_INTERVAL 512 |
| |
| /* |
| * Check this_cpu to ensure it is balanced within domain. Attempt to move |
| * tasks if there is an imbalance. |
| */ |
| static int load_balance(int this_cpu, struct rq *this_rq, |
| struct sched_domain *sd, enum cpu_idle_type idle, |
| int *balance, cpumask_t *cpus) |
| { |
| int ld_moved, all_pinned = 0, active_balance = 0, sd_idle = 0; |
| struct sched_group *group; |
| unsigned long imbalance; |
| struct rq *busiest; |
| unsigned long flags; |
| |
| cpus_setall(*cpus); |
| |
| /* |
| * When power savings policy is enabled for the parent domain, idle |
| * sibling can pick up load irrespective of busy siblings. In this case, |
| * let the state of idle sibling percolate up as CPU_IDLE, instead of |
| * portraying it as CPU_NOT_IDLE. |
| */ |
| if (idle != CPU_NOT_IDLE && sd->flags & SD_SHARE_CPUPOWER && |
| !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
| sd_idle = 1; |
| |
| schedstat_inc(sd, lb_count[idle]); |
| |
| redo: |
| update_shares(sd); |
| group = find_busiest_group(sd, this_cpu, &imbalance, idle, &sd_idle, |
| cpus, balance); |
| |
| if (*balance == 0) |
| goto out_balanced; |
| |
| if (!group) { |
| schedstat_inc(sd, lb_nobusyg[idle]); |
| goto out_balanced; |
| } |
| |
| busiest = find_busiest_queue(group, idle, imbalance, cpus); |
| if (!busiest) { |
| schedstat_inc(sd, lb_nobusyq[idle]); |
| goto out_balanced; |
| } |
| |
| BUG_ON(busiest == this_rq); |
| |
| schedstat_add(sd, lb_imbalance[idle], imbalance); |
| |
| ld_moved = 0; |
| if (busiest->nr_running > 1) { |
| /* |
| * Attempt to move tasks. If find_busiest_group has found |
| * an imbalance but busiest->nr_running <= 1, the group is |
| * still unbalanced. ld_moved simply stays zero, so it is |
| * correctly treated as an imbalance. |
| */ |
| local_irq_save(flags); |
| double_rq_lock(this_rq, busiest); |
| ld_moved = move_tasks(this_rq, this_cpu, busiest, |
| imbalance, sd, idle, &all_pinned); |
| double_rq_unlock(this_rq, busiest); |
| local_irq_restore(flags); |
| |
| /* |
| * some other cpu did the load balance for us. |
| */ |
| if (ld_moved && this_cpu != smp_processor_id()) |
| resched_cpu(this_cpu); |
| |
| /* All tasks on this runqueue were pinned by CPU affinity */ |
| if (unlikely(all_pinned)) { |
| cpu_clear(cpu_of(busiest), *cpus); |
| if (!cpus_empty(*cpus)) |
| goto redo; |
| goto out_balanced; |
| } |
| } |
| |
| if (!ld_moved) { |
| schedstat_inc(sd, lb_failed[idle]); |
| sd->nr_balance_failed++; |
| |
| if (unlikely(sd->nr_balance_failed > sd->cache_nice_tries+2)) { |
| |
| spin_lock_irqsave(&busiest->lock, flags); |
| |
| /* don't kick the migration_thread, if the curr |
| * task on busiest cpu can't be moved to this_cpu |
| */ |
| if (!cpu_isset(this_cpu, busiest->curr->cpus_allowed)) { |
| spin_unlock_irqrestore(&busiest->lock, flags); |
| all_pinned = 1; |
| goto out_one_pinned; |
| } |
| |
| if (!busiest->active_balance) { |
| busiest->active_balance = 1; |
| busiest->push_cpu = this_cpu; |
| active_balance = 1; |
| } |
| spin_unlock_irqrestore(&busiest->lock, flags); |
| if (active_balance) |
| wake_up_process(busiest->migration_thread); |
| |
| /* |
| * We've kicked active balancing, reset the failure |
| * counter. |
| */ |
| sd->nr_balance_failed = sd->cache_nice_tries+1; |
| } |
| } else |
| sd->nr_balance_failed = 0; |
| |
| if (likely(!active_balance)) { |
| /* We were unbalanced, so reset the balancing interval */ |
| sd->balance_interval = sd->min_interval; |
| } else { |
| /* |
| * If we've begun active balancing, start to back off. This |
| * case may not be covered by the all_pinned logic if there |
| * is only 1 task on the busy runqueue (because we don't call |
| * move_tasks). |
| */ |
| if (sd->balance_interval < sd->max_interval) |
| sd->balance_interval *= 2; |
| } |
| |
| if (!ld_moved && !sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
| !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
| ld_moved = -1; |
| |
| goto out; |
| |
| out_balanced: |
| schedstat_inc(sd, lb_balanced[idle]); |
| |
| sd->nr_balance_failed = 0; |
| |
| out_one_pinned: |
| /* tune up the balancing interval */ |
| if ((all_pinned && sd->balance_interval < MAX_PINNED_INTERVAL) || |
| (sd->balance_interval < sd->max_interval)) |
| sd->balance_interval *= 2; |
| |
| if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
| !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
| ld_moved = -1; |
| else |
| ld_moved = 0; |
| out: |
| if (ld_moved) |
| update_shares(sd); |
| return ld_moved; |
| } |
| |
| /* |
| * Check this_cpu to ensure it is balanced within domain. Attempt to move |
| * tasks if there is an imbalance. |
| * |
| * Called from schedule when this_rq is about to become idle (CPU_NEWLY_IDLE). |
| * this_rq is locked. |
| */ |
| static int |
| load_balance_newidle(int this_cpu, struct rq *this_rq, struct sched_domain *sd, |
| cpumask_t *cpus) |
| { |
| struct sched_group *group; |
| struct rq *busiest = NULL; |
| unsigned long imbalance; |
| int ld_moved = 0; |
| int sd_idle = 0; |
| int all_pinned = 0; |
| |
| cpus_setall(*cpus); |
| |
| /* |
| * When power savings policy is enabled for the parent domain, idle |
| * sibling can pick up load irrespective of busy siblings. In this case, |
| * let the state of idle sibling percolate up as IDLE, instead of |
| * portraying it as CPU_NOT_IDLE. |
| */ |
| if (sd->flags & SD_SHARE_CPUPOWER && |
| !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
| sd_idle = 1; |
| |
| schedstat_inc(sd, lb_count[CPU_NEWLY_IDLE]); |
| redo: |
| update_shares_locked(this_rq, sd); |
| group = find_busiest_group(sd, this_cpu, &imbalance, CPU_NEWLY_IDLE, |
| &sd_idle, cpus, NULL); |
| if (!group) { |
| schedstat_inc(sd, lb_nobusyg[CPU_NEWLY_IDLE]); |
| goto out_balanced; |
| } |
| |
| busiest = find_busiest_queue(group, CPU_NEWLY_IDLE, imbalance, cpus); |
| if (!busiest) { |
| schedstat_inc(sd, lb_nobusyq[CPU_NEWLY_IDLE]); |
| goto out_balanced; |
| } |
| |
| BUG_ON(busiest == this_rq); |
| |
| schedstat_add(sd, lb_imbalance[CPU_NEWLY_IDLE], imbalance); |
| |
| ld_moved = 0; |
| if (busiest->nr_running > 1) { |
| /* Attempt to move tasks */ |
| double_lock_balance(this_rq, busiest); |
| /* this_rq->clock is already updated */ |
| update_rq_clock(busiest); |
| ld_moved = move_tasks(this_rq, this_cpu, busiest, |
| imbalance, sd, CPU_NEWLY_IDLE, |
| &all_pinned); |
| spin_unlock(&busiest->lock); |
| |
| if (unlikely(all_pinned)) { |
| cpu_clear(cpu_of(busiest), *cpus); |
| if (!cpus_empty(*cpus)) |
| goto redo; |
| } |
| } |
| |
| if (!ld_moved) { |
| schedstat_inc(sd, lb_failed[CPU_NEWLY_IDLE]); |
| if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
| !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
| return -1; |
| } else |
| sd->nr_balance_failed = 0; |
| |
| update_shares_locked(this_rq, sd); |
| return ld_moved; |
| |
| out_balanced: |
| schedstat_inc(sd, lb_balanced[CPU_NEWLY_IDLE]); |
| if (!sd_idle && sd->flags & SD_SHARE_CPUPOWER && |
| !test_sd_parent(sd, SD_POWERSAVINGS_BALANCE)) |
| return -1; |
| sd->nr_balance_failed = 0; |
| |
| return 0; |
| } |
| |
| /* |
| * idle_balance is called by schedule() if this_cpu is about to become |
| * idle. Attempts to pull tasks from other CPUs. |
| */ |
| static void idle_balance(int this_cpu, struct rq *this_rq) |
| { |
| struct sched_domain *sd; |
| int pulled_task = -1; |
| unsigned long next_balance = jiffies + HZ; |
| cpumask_t tmpmask; |
| |
| for_each_domain(this_cpu, sd) { |
| unsigned long interval; |
| |
| if (!(sd->flags & SD_LOAD_BALANCE)) |
| continue; |
| |
| if (sd->flags & SD_BALANCE_NEWIDLE) |
| /* If we've pulled tasks over stop searching: */ |
| pulled_task = load_balance_newidle(this_cpu, this_rq, |
| sd, &tmpmask); |
| |
| interval = msecs_to_jiffies(sd->balance_interval); |
| if (time_after(next_balance, sd->last_balance + interval)) |
| next_balance = sd->last_balance + interval; |
| if (pulled_task) |
| break; |
| } |
| if (pulled_task || time_after(jiffies, this_rq->next_balance)) { |
| /* |
| * We are going idle. next_balance may be set based on |
| * a busy processor. So reset next_balance. |
| */ |
| this_rq->next_balance = next_balance; |
| } |
| } |
| |
| /* |
| * active_load_balance is run by migration threads. It pushes running tasks |
| * off the busiest CPU onto idle CPUs. It requires at least 1 task to be |
| * running on each physical CPU where possible, and avoids physical / |
| * logical imbalances. |
| * |
| * Called with busiest_rq locked. |
| */ |
| static void active_load_balance(struct rq *busiest_rq, int busiest_cpu) |
| { |
| int target_cpu = busiest_rq->push_cpu; |
| struct sched_domain *sd; |
| struct rq *target_rq; |
| |
| /* Is there any task to move? */ |
| if (busiest_rq->nr_running <= 1) |
| return; |
| |
| target_rq = cpu_rq(target_cpu); |
| |
| /* |
| * This condition is "impossible", if it occurs |
| * we need to fix it. Originally reported by |
| * Bjorn Helgaas on a 128-cpu setup. |
| */ |
| BUG_ON(busiest_rq == target_rq); |
| |
| /* move a task from busiest_rq to target_rq */ |
| double_lock_balance(busiest_rq, target_rq); |
| update_rq_clock(busiest_rq); |
| update_rq_clock(target_rq); |
| |
| /* Search for an sd spanning us and the target CPU. */ |
| for_each_domain(target_cpu, sd) { |
| if ((sd->flags & SD_LOAD_BALANCE) && |
| cpu_isset(busiest_cpu, sd->span)) |
| break; |
| } |
| |
| if (likely(sd)) { |
| schedstat_inc(sd, alb_count); |
| |
| if (move_one_task(target_rq, target_cpu, busiest_rq, |
| sd, CPU_IDLE)) |
| schedstat_inc(sd, alb_pushed); |
| else |
| schedstat_inc(sd, alb_failed); |
| } |
| spin_unlock(&target_rq->lock); |
| } |
| |
| #ifdef CONFIG_NO_HZ |
| static struct { |
| atomic_t load_balancer; |
| cpumask_t cpu_mask; |
| } nohz ____cacheline_aligned = { |
| .load_balancer = ATOMIC_INIT(-1), |
| .cpu_mask = CPU_MASK_NONE, |
| }; |
| |
| /* |
| * This routine will try to nominate the ilb (idle load balancing) |
| * owner among the cpus whose ticks are stopped. ilb owner will do the idle |
| * load balancing on behalf of all those cpus. If all the cpus in the system |
| * go into this tickless mode, then there will be no ilb owner (as there is |
| * no need for one) and all the cpus will sleep till the next wakeup event |
| * arrives... |
| * |
| * For the ilb owner, tick is not stopped. And this tick will be used |
| * for idle load balancing. ilb owner will still be part of |
| * nohz.cpu_mask.. |
| * |
| * While stopping the tick, this cpu will become the ilb owner if there |
| * is no other owner. And will be the owner till that cpu becomes busy |
| * or if all cpus in the system stop their ticks at which point |
| * there is no need for ilb owner. |
| * |
| * When the ilb owner becomes busy, it nominates another owner, during the |
| * next busy scheduler_tick() |
| */ |
| int select_nohz_load_balancer(int stop_tick) |
| { |
| int cpu = smp_processor_id(); |
| |
| if (stop_tick) { |
| cpu_set(cpu, nohz.cpu_mask); |
| cpu_rq(cpu)->in_nohz_recently = 1; |
| |
| /* |
| * If we are going offline and still the leader, give up! |
| */ |
| if (cpu_is_offline(cpu) && |
| atomic_read(&nohz.load_balancer) == cpu) { |
| if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) |
| BUG(); |
| return 0; |
| } |
| |
| /* time for ilb owner also to sleep */ |
| if (cpus_weight(nohz.cpu_mask) == num_online_cpus()) { |
| if (atomic_read(&nohz.load_balancer) == cpu) |
| atomic_set(&nohz.load_balancer, -1); |
| return 0; |
| } |
| |
| if (atomic_read(&nohz.load_balancer) == -1) { |
| /* make me the ilb owner */ |
| if (atomic_cmpxchg(&nohz.load_balancer, -1, cpu) == -1) |
| return 1; |
| } else if (atomic_read(&nohz.load_balancer) == cpu) |
| return 1; |
| } else { |
| if (!cpu_isset(cpu, nohz.cpu_mask)) |
| return 0; |
| |
| cpu_clear(cpu, nohz.cpu_mask); |
| |
| if (atomic_read(&nohz.load_balancer) == cpu) |
| if (atomic_cmpxchg(&nohz.load_balancer, cpu, -1) != cpu) |
| BUG(); |
| } |
| return 0; |
| } |
| #endif |
| |
| static DEFINE_SPINLOCK(balancing); |
| |
| /* |
| * It checks each scheduling domain to see if it is due to be balanced, |
| * and initiates a balancing operation if so. |
| * |
| * Balancing parameters are set up in arch_init_sched_domains. |
| */ |
| static void rebalance_domains(int cpu, enum cpu_idle_type idle) |
| { |
| int balance = 1; |
| struct rq *rq = cpu_rq(cpu); |
| unsigned long interval; |
| struct sched_domain *sd; |
| /* Earliest time when we have to do rebalance again */ |
| unsigned long next_balance = jiffies + 60*HZ; |
| int update_next_balance = 0; |
| int need_serialize; |
| cpumask_t tmp; |
| |
| for_each_domain(cpu, sd) { |
| if (!(sd->flags & SD_LOAD_BALANCE)) |
| continue; |
| |
| interval = sd->balance_interval; |
| if (idle != CPU_IDLE) |
| interval *= sd->busy_factor; |
| |
| /* scale ms to jiffies */ |
| interval = msecs_to_jiffies(interval); |
| if (unlikely(!interval)) |
| interval = 1; |
| if (interval > HZ*NR_CPUS/10) |
| interval = HZ*NR_CPUS/10; |
| |
| need_serialize = sd->flags & SD_SERIALIZE; |
| |
| if (need_serialize) { |
| if (!spin_trylock(&balancing)) |
| goto out; |
| } |
| |
| if (time_after_eq(jiffies, sd->last_balance + interval)) { |
| if (load_balance(cpu, rq, sd, idle, &balance, &tmp)) { |
| /* |
| * We've pulled tasks over so either we're no |
| * longer idle, or one of our SMT siblings is |
| * not idle. |
| */ |
| idle = CPU_NOT_IDLE; |
| } |
| sd->last_balance = jiffies; |
| } |
| if (need_serialize) |
| spin_unlock(&balancing); |
| out: |
| if (time_after(next_balance, sd->last_balance + interval)) { |
| next_balance = sd->last_balance + interval; |
| update_next_balance = 1; |
| } |
| |
| /* |
| * Stop the load balance at this level. There is another |
| * CPU in our sched group which is doing load balancing more |
| * actively. |
| */ |
| if (!balance) |
| break; |
| } |
| |
| /* |
| * next_balance will be updated only when there is a need. |
| * When the cpu is attached to null domain for ex, it will not be |
| * updated. |
| */ |
| if (likely(update_next_balance)) |
| rq->next_balance = next_balance; |
| } |
| |
| /* |
| * run_rebalance_domains is triggered when needed from the scheduler tick. |
| * In CONFIG_NO_HZ case, the idle load balance owner will do the |
| * rebalancing for all the cpus for whom scheduler ticks are stopped. |
| */ |
| static void run_rebalance_domains(struct softirq_action *h) |
| { |
| int this_cpu = smp_processor_id(); |
| struct rq *this_rq = cpu_rq(this_cpu); |
| enum cpu_idle_type idle = this_rq->idle_at_tick ? |
| CPU_IDLE : CPU_NOT_IDLE; |
| |
| rebalance_domains(this_cpu, idle); |
| |
| #ifdef CONFIG_NO_HZ |
| /* |
| * If this cpu is the owner for idle load balancing, then do the |
| * balancing on behalf of the other idle cpus whose ticks are |
| * stopped. |
| */ |
| if (this_rq->idle_at_tick && |
| atomic_read(&nohz.load_balancer) == this_cpu) { |
| cpumask_t cpus = nohz.cpu_mask; |
| struct rq *rq; |
| int balance_cpu; |
| |
| cpu_clear(this_cpu, cpus); |
| for_each_cpu_mask(balance_cpu, cpus) { |
| /* |
| * If this cpu gets work to do, stop the load balancing |
| * work being done for other cpus. Next load |
| * balancing owner will pick it up. |
| */ |
| if (need_resched()) |
| break; |
| |
| rebalance_domains(balance_cpu, CPU_IDLE); |
| |
| rq = cpu_rq(balance_cpu); |
| if (time_after(this_rq->next_balance, rq->next_balance)) |
| this_rq->next_balance = rq->next_balance; |
| } |
| } |
| #endif |
| } |
| |
| /* |
| * Trigger the SCHED_SOFTIRQ if it is time to do periodic load balancing. |
| * |
| * In case of CONFIG_NO_HZ, this is the place where we nominate a new |
| * idle load balancing owner or decide to stop the periodic load balancing, |
| * if the whole system is idle. |
| */ |
| static inline void trigger_load_balance(struct rq *rq, int cpu) |
| { |
| #ifdef CONFIG_NO_HZ |
| /* |
| * If we were in the nohz mode recently and busy at the current |
| * scheduler tick, then check if we need to nominate new idle |
| * load balancer. |
| */ |
| if (rq->in_nohz_recently && !rq->idle_at_tick) { |
| rq->in_nohz_recently = 0; |
| |
| if (atomic_read(&nohz.load_balancer) == cpu) { |
| cpu_clear(cpu, nohz.cpu_mask); |
| atomic_set(&nohz.load_balancer, -1); |
| } |
| |
| if (atomic_read(&nohz.load_balancer) == -1) { |
| /* |
| * simple selection for now: Nominate the |
| * first cpu in the nohz list to be the next |
| * ilb owner. |
| * |
| * TBD: Traverse the sched domains and nominate |
| * the nearest cpu in the nohz.cpu_mask. |
| */ |
| int ilb = first_cpu(nohz.cpu_mask); |
| |
| if (ilb < nr_cpu_ids) |
| resched_cpu(ilb); |
| } |
| } |
| |
| /* |
| * If this cpu is idle and doing idle load balancing for all the |
| * cpus with ticks stopped, is it time for that to stop? |
| */ |
| if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) == cpu && |
| cpus_weight(nohz.cpu_mask) == num_online_cpus()) { |
| resched_cpu(cpu); |
| return; |
| } |
| |
| /* |
| * If this cpu is idle and the idle load balancing is done by |
| * someone else, then no need raise the SCHED_SOFTIRQ |
| */ |
| if (rq->idle_at_tick && atomic_read(&nohz.load_balancer) != cpu && |
| cpu_isset(cpu, nohz.cpu_mask)) |
| return; |
| #endif |
| if (time_after_eq(jiffies, rq->next_balance)) |
| raise_softirq(SCHED_SOFTIRQ); |
| } |
| |
| #else /* CONFIG_SMP */ |
| |
| /* |
| * on UP we do not need to balance between CPUs: |
| */ |
| static inline void idle_balance(int cpu, struct rq *rq) |
| { |
| } |
| |
| #endif |
| |
| DEFINE_PER_CPU(struct kernel_stat, kstat); |
| |
| EXPORT_PER_CPU_SYMBOL(kstat); |
| |
| /* |
| * Return p->sum_exec_runtime plus any more ns on the sched_clock |
| * that have not yet been banked in case the task is currently running. |
| */ |
| unsigned long long task_sched_runtime(struct task_struct *p) |
| { |
| unsigned long flags; |
| u64 ns, delta_exec; |
| struct rq *rq; |
| |
| rq = task_rq_lock(p, &flags); |
| ns = p->se.sum_exec_runtime; |
| if (task_current(rq, p)) { |
| update_rq_clock(rq); |
| delta_exec = rq->clock - p->se.exec_start; |
| if ((s64)delta_exec > 0) |
| ns += delta_exec; |
| } |
| task_rq_unlock(rq, &flags); |
| |
| return ns; |
| } |
| |
| /* |
| * Account user cpu time to a process. |
| * @p: the process that the cpu time gets accounted to |
| * @cputime: the cpu time spent in user space since the last update |
| */ |
| void account_user_time(struct task_struct *p, cputime_t cputime) |
| { |
| struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
| cputime64_t tmp; |
| |
| p->utime = cputime_add(p->utime, cputime); |
| |
| /* Add user time to cpustat. */ |
| tmp = cputime_to_cputime64(cputime); |
| if (TASK_NICE(p) > 0) |
| cpustat->nice = cputime64_add(cpustat->nice, tmp); |
| else |
| cpustat->user = cputime64_add(cpustat->user, tmp); |
| } |
| |
| /* |
| * Account guest cpu time to a process. |
| * @p: the process that the cpu time gets accounted to |
| * @cputime: the cpu time spent in virtual machine since the last update |
| */ |
| static void account_guest_time(struct task_struct *p, cputime_t cputime) |
| { |
| cputime64_t tmp; |
| struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
| |
| tmp = cputime_to_cputime64(cputime); |
| |
| p->utime = cputime_add(p->utime, cputime); |
| p->gtime = cputime_add(p->gtime, cputime); |
| |
| cpustat->user = cputime64_add(cpustat->user, tmp); |
| cpustat->guest = cputime64_add(cpustat->guest, tmp); |
| } |
| |
| /* |
| * Account scaled user cpu time to a process. |
| * @p: the process that the cpu time gets accounted to |
| * @cputime: the cpu time spent in user space since the last update |
| */ |
| void account_user_time_scaled(struct task_struct *p, cputime_t cputime) |
| { |
| p->utimescaled = cputime_add(p->utimescaled, cputime); |
| } |
| |
| /* |
| * Account system cpu time to a process. |
| * @p: the process that the cpu time gets accounted to |
| * @hardirq_offset: the offset to subtract from hardirq_count() |
| * @cputime: the cpu time spent in kernel space since the last update |
| */ |
| void account_system_time(struct task_struct *p, int hardirq_offset, |
| cputime_t cputime) |
| { |
| struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
| struct rq *rq = this_rq(); |
| cputime64_t tmp; |
| |
| if ((p->flags & PF_VCPU) && (irq_count() - hardirq_offset == 0)) { |
| account_guest_time(p, cputime); |
| return; |
| } |
| |
| p->stime = cputime_add(p->stime, cputime); |
| |
| /* Add system time to cpustat. */ |
| tmp = cputime_to_cputime64(cputime); |
| if (hardirq_count() - hardirq_offset) |
| cpustat->irq = cputime64_add(cpustat->irq, tmp); |
| else if (softirq_count()) |
| cpustat->softirq = cputime64_add(cpustat->softirq, tmp); |
| else if (p != rq->idle) |
| cpustat->system = cputime64_add(cpustat->system, tmp); |
| else if (atomic_read(&rq->nr_iowait) > 0) |
| cpustat->iowait = cputime64_add(cpustat->iowait, tmp); |
| else |
| cpustat->idle = cputime64_add(cpustat->idle, tmp); |
| /* Account for system time used */ |
| acct_update_integrals(p); |
| } |
| |
| /* |
| * Account scaled system cpu time to a process. |
| * @p: the process that the cpu time gets accounted to |
| * @hardirq_offset: the offset to subtract from hardirq_count() |
| * @cputime: the cpu time spent in kernel space since the last update |
| */ |
| void account_system_time_scaled(struct task_struct *p, cputime_t cputime) |
| { |
| p->stimescaled = cputime_add(p->stimescaled, cputime); |
| } |
| |
| /* |
| * Account for involuntary wait time. |
| * @p: the process from which the cpu time has been stolen |
| * @steal: the cpu time spent in involuntary wait |
| */ |
| void account_steal_time(struct task_struct *p, cputime_t steal) |
| { |
| struct cpu_usage_stat *cpustat = &kstat_this_cpu.cpustat; |
| cputime64_t tmp = cputime_to_cputime64(steal); |
| struct rq *rq = this_rq(); |
| |
| if (p == rq->idle) { |
| p->stime = cputime_add(p->stime, steal); |
| if (atomic_read(&rq->nr_iowait) > 0) |
| cpustat->iowait = cputime64_add(cpustat->iowait, tmp); |
| else |
| cpustat->idle = cputime64_add(cpustat->idle, tmp); |
| } else |
| cpustat->steal = cputime64_add(cpustat->steal, tmp); |
| } |
| |
| /* |
| * This function gets called by the timer code, with HZ frequency. |
| * We call it with interrupts disabled. |
| * |
| * It also gets called by the fork code, when changing the parent's |
| * timeslices. |
| */ |
| void scheduler_tick(void) |
| { |
| int cpu = smp_processor_id(); |
| struct rq *rq = cpu_rq(cpu); |
| struct task_struct *curr = rq->curr; |
| |
| sched_clock_tick(); |
| |
| spin_lock(&rq->lock); |
| update_rq_clock(rq); |
| update_cpu_load(rq); |
| curr->sched_class->task_tick(rq, curr, 0); |
| spin_unlock(&rq->lock); |
| |
| #ifdef CONFIG_SMP |
| rq->idle_at_tick = idle_cpu(cpu); |
| trigger_load_balance(rq, cpu); |
| #endif |
| } |
| |
| #if defined(CONFIG_PREEMPT) && (defined(CONFIG_DEBUG_PREEMPT) || \ |
| defined(CONFIG_PREEMPT_TRACER)) |
| |
| static inline unsigned long get_parent_ip(unsigned long addr) |
| { |
| if (in_lock_functions(addr)) { |
| addr = CALLER_ADDR2; |
| if (in_lock_functions(addr)) |
| addr = CALLER_ADDR3; |
| } |
| return addr; |
| } |
| |
| void __kprobes add_preempt_count(int val) |
| { |
| #ifdef CONFIG_DEBUG_PREEMPT |
| /* |
| * Underflow? |
| */ |
| if (DEBUG_LOCKS_WARN_ON((preempt_count() < 0))) |
| return; |
| #endif |
| preempt_count() += val; |
| #ifdef CONFIG_DEBUG_PREEMPT |
| /* |
| * Spinlock count overflowing soon? |
| */ |
| DEBUG_LOCKS_WARN_ON((preempt_count() & PREEMPT_MASK) >= |
| PREEMPT_MASK - 10); |
| #endif |
| if (preempt_count() == val) |
| trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); |
| } |
| EXPORT_SYMBOL(add_preempt_count); |
| |
| void __kprobes sub_preempt_count(int val) |
| { |
| #ifdef CONFIG_DEBUG_PREEMPT |
| /* |
| * Underflow? |
| */ |
| if (DEBUG_LOCKS_WARN_ON(val > preempt_count())) |
| return; |
| /* |
| * Is the spinlock portion underflowing? |
| */ |
| if (DEBUG_LOCKS_WARN_ON((val < PREEMPT_MASK) && |
| !(preempt_count() & PREEMPT_MASK))) |
| return; |
| #endif |
| |
| if (preempt_count() == val) |
| trace_preempt_on(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1)); |
| preempt_count() -= val; |
| } |
| EXPORT_SYMBOL(sub_preempt_count); |
| |
| #endif |
| |
| /* |
| * Print scheduling while atomic bug: |
| */ |
| static noinline void __schedule_bug(struct task_struct *prev) |
| { |
| struct pt_regs *regs = get_irq_regs(); |
| |
| printk(KERN_ERR "BUG: scheduling while atomic: %s/%d/0x%08x\n", |
| prev->comm, prev->pid, preempt_count()); |
| |
| debug_show_held_locks(prev); |
| print_modules(); |
| if (irqs_disabled()) |
| print_irqtrace_events(prev); |
| |
| if (regs) |
| show_regs(regs); |
| else |
| dump_stack(); |
| } |
| |
| /* |
| * Various schedule()-time debugging checks and statistics: |
| */ |
| static inline void schedule_debug(struct task_struct *prev) |
| { |
| /* |
| * Test if we are atomic. Since do_exit() needs to call into |
| * schedule() atomically, we ignore that path for now. |
| * Otherwise, whine if we are scheduling when we should not be. |
| */ |
| if (unlikely(in_atomic_preempt_off() && !prev->exit_state)) |
| __schedule_bug(prev); |
| |
| profile_hit(SCHED_PROFILING, __builtin_return_address(0)); |
| |
| schedstat_inc(this_rq(), sched_count); |
| #ifdef CONFIG_SCHEDSTATS |
| if (unlikely(prev->lock_depth >= 0)) { |
| schedstat_inc(this_rq(), bkl_count); |
| schedstat_inc(prev, sched_info.bkl_count); |
| } |
| #endif |
| } |
| |
| /* |
| * Pick up the highest-prio task: |
| */ |
| static inline struct task_struct * |
| pick_next_task(struct rq *rq, struct task_struct *prev) |
| { |
| const struct sched_class *class; |
| struct task_struct *p; |
| |
| /* |
| * Optimization: we know that if all tasks are in |
| * the fair class we can call that function directly: |
| */ |
| if (likely(rq->nr_running == rq->cfs.nr_running)) { |
| p = fair_sched_class.pick_next_task(rq); |
| if (likely(p)) |
| return p; |
| } |
| |
| class = sched_class_highest; |
| for ( ; ; ) { |
| p = class->pick_next_task(rq); |
| if (p) |
| return p; |
| /* |
| * Will never be NULL as the idle class always |
| * returns a non-NULL p: |
| */ |
| class = class->next; |
| } |
| } |
| |
| /* |
| * schedule() is the main scheduler function. |
| */ |
| asmlinkage void __sched schedule(void) |
| { |
| struct task_struct *prev, *next; |
| unsigned long *switch_count; |
| struct rq *rq; |
| int cpu, hrtick = sched_feat(HRTICK); |
| |
| need_resched: |
| preempt_disable(); |
| cpu = smp_processor_id(); |
| rq = cpu_rq(cpu); |
| rcu_qsctr_inc(cpu); |
| prev = rq->curr; |
| switch_count = &prev->nivcsw; |
| |
| release_kernel_lock(prev); |
| need_resched_nonpreemptible: |
| |
| schedule_debug(prev); |
| |
| if (hrtick) |
| hrtick_clear(rq); |
| |
| /* |
| * Do the rq-clock update outside the rq lock: |
| */ |
| local_irq_disable(); |
| update_rq_clock(rq); |
| spin_lock(&rq->lock); |
| clear_tsk_need_resched(prev); |
| |
| if (prev->state && !(preempt_count() & PREEMPT_ACTIVE)) { |
| if (unlikely(signal_pending_state(prev->state, prev))) |
| prev->state = TASK_RUNNING; |
| else |
| deactivate_task(rq, prev, 1); |
| switch_count = &prev->nvcsw; |
| } |
| |
| #ifdef CONFIG_SMP |
| if (prev->sched_class->pre_schedule) |
| prev->sched_class->pre_schedule(rq, prev); |
| #endif |
| |
| if (unlikely(!rq->nr_running)) |
| idle_balance(cpu, rq); |
| |
| prev->sched_class->put_prev_task(rq, prev); |
| next = pick_next_task(rq, prev); |
| |
| if (likely(prev != next)) { |
| sched_info_switch(prev, next); |
| |
| rq->nr_switches++; |
| rq->curr = next; |
| ++*switch_count; |
| |
| context_switch(rq, prev, next); /* unlocks the rq */ |
| /* |
| * the context switch might have flipped the stack from under |
| * us, hence refresh the local variables. |
| */ |
| cpu = smp_processor_id(); |
| rq = cpu_rq(cpu); |
| } else |
| spin_unlock_irq(&rq->lock); |
| |
| if (hrtick) |
| hrtick_set(rq); |
| |
| if (unlikely(reacquire_kernel_lock(current) < 0)) |
| goto need_resched_nonpreemptible; |
| |
| preempt_enable_no_resched(); |
| if (unlikely(test_thread_flag(TIF_NEED_RESCHED))) |
| goto need_resched; |
| } |
| EXPORT_SYMBOL(schedule); |
| |
| #ifdef CONFIG_PREEMPT |
| /* |
| * this is the entry point to schedule() from in-kernel preemption |
| * off of preempt_enable. Kernel preemptions off return from interrupt |
| * occur there and call schedule directly. |
| */ |
| asmlinkage void __sched preempt_schedule(void) |
| { |
| struct thread_info *ti = current_thread_info(); |
| |
| /* |
| * If there is a non-zero preempt_count or interrupts are disabled, |
| * we do not want to preempt the current task. Just return.. |
| */ |
| if (likely(ti->preempt_count || irqs_disabled())) |
| return; |
| |
| do { |
| add_preempt_count(PREEMPT_ACTIVE); |
| schedule(); |
| sub_preempt_count(PREEMPT_ACTIVE); |
| |
| /* |
| * Check again in case we missed a preemption opportunity |
| * between schedule and now. |
| */ |
| barrier(); |
| } while (unlikely(test_thread_flag(TIF_NEED_RESCHED))); |
| } |
| EXPORT_SYMBOL(preempt_schedule); |
| |
| /* |
| * this is the entry point to schedule() from kernel preemption |
| * off of irq context. |
| * Note, that this is called and return with irqs disabled. This will |
| * protect us against recursive calling from irq. |
| */ |
| asmlinkage void __sched preempt_schedule_irq(void) |
| { |
| struct thread_info *ti = current_thread_info(); |
| |
| /* Catch callers which need to be fixed */ |
| BUG_ON(ti->preempt_count || !irqs_disabled()); |
| |
| do { |
| add_preempt_count(PREEMPT_ACTIVE); |
| local_irq_enable(); |
| schedule(); |
| local_irq_disable(); |
| sub_preempt_count(PREEMPT_ACTIVE); |
| |
| /* |
| * Check again in case we missed a preemption opportunity |
| * between schedule and now. |
| */ |
| barrier(); |
| } while (unlikely(test_thread_flag(TIF_NEED_RESCHED))); |
| } |
| |
| #endif /* CONFIG_PREEMPT */ |
| |
| int default_wake_function(wait_queue_t *curr, unsigned mode, int sync, |
| void *key) |
| { |
| return try_to_wake_up(curr->private, mode, sync); |
| } |
| EXPORT_SYMBOL(default_wake_function); |
| |
| /* |
| * The core wakeup function. Non-exclusive wakeups (nr_exclusive == 0) just |
| * wake everything up. If it's an exclusive wakeup (nr_exclusive == small +ve |
| * number) then we wake all the non-exclusive tasks and one exclusive task. |
| * |
| * There are circumstances in which we can try to wake a task which has already |
| * started to run but is not in state TASK_RUNNING. try_to_wake_up() returns |
| * zero in this (rare) case, and we handle it by continuing to scan the queue. |
| */ |
| static void __wake_up_common(wait_queue_head_t *q, unsigned int mode, |
| int nr_exclusive, int sync, void *key) |
| { |
| wait_queue_t *curr, *next; |
| |
| list_for_each_entry_safe(curr, next, &q->task_list, task_list) { |
| unsigned flags = curr->flags; |
| |
| if (curr->func(curr, mode, sync, key) && |
| (flags & WQ_FLAG_EXCLUSIVE) && !--nr_exclusive) |
| break; |
| } |
| } |
| |
| /** |
| * __wake_up - wake up threads blocked on a waitqueue. |
| * @q: the waitqueue |
| * @mode: which threads |
| * @nr_exclusive: how many wake-one or wake-many threads to wake up |
| * @key: is directly passed to the wakeup function |
| */ |
| void __wake_up(wait_queue_head_t *q, unsigned int mode, |
| int nr_exclusive, void *key) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&q->lock, flags); |
| __wake_up_common(q, mode, nr_exclusive, 0, key); |
| spin_unlock_irqrestore(&q->lock, flags); |
| } |
| EXPORT_SYMBOL(__wake_up); |
| |
| /* |
| * Same as __wake_up but called with the spinlock in wait_queue_head_t held. |
| */ |
| void __wake_up_locked(wait_queue_head_t *q, unsigned int mode) |
| { |
| __wake_up_common(q, mode, 1, 0, NULL); |
| } |
| |
| /** |
| * __wake_up_sync - wake up threads blocked on a waitqueue. |
| * @q: the waitqueue |
| * @mode: which threads |
| * @nr_exclusive: how many wake-one or wake-many threads to wake up |
| * |
| * The sync wakeup differs that the waker knows that it will schedule |
| * away soon, so while the target thread will be woken up, it will not |
| * be migrated to another CPU - ie. the two threads are 'synchronized' |
| * with each other. This can prevent needless bouncing between CPUs. |
| * |
| * On UP it can prevent extra preemption. |
| */ |
| void |
| __wake_up_sync(wait_queue_head_t *q, unsigned int mode, int nr_exclusive) |
| { |
| unsigned long flags; |
| int sync = 1; |
| |
| if (unlikely(!q)) |
| return; |
| |
| if (unlikely(!nr_exclusive)) |
| sync = 0; |
| |
| spin_lock_irqsave(&q->lock, flags); |
| __wake_up_common(q, mode, nr_exclusive, sync, NULL); |
| spin_unlock_irqrestore(&q->lock, flags); |
| } |
| EXPORT_SYMBOL_GPL(__wake_up_sync); /* For internal use only */ |
| |
| void complete(struct completion *x) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&x->wait.lock, flags); |
| x->done++; |
| __wake_up_common(&x->wait, TASK_NORMAL, 1, 0, NULL); |
| spin_unlock_irqrestore(&x->wait.lock, flags); |
| } |
| EXPORT_SYMBOL(complete); |
| |
| void complete_all(struct completion *x) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&x->wait.lock, flags); |
| x->done += UINT_MAX/2; |
| __wake_up_common(&x->wait, TASK_NORMAL, 0, 0, NULL); |
| spin_unlock_irqrestore(&x->wait.lock, flags); |
| } |
| EXPORT_SYMBOL(complete_all); |
| |
| static inline long __sched |
| do_wait_for_common(struct completion *x, long timeout, int state) |
| { |
| if (!x->done) { |
| DECLARE_WAITQUEUE(wait, current); |
| |
| wait.flags |= WQ_FLAG_EXCLUSIVE; |
| __add_wait_queue_tail(&x->wait, &wait); |
| do { |
| if ((state == TASK_INTERRUPTIBLE && |
| signal_pending(current)) || |
| (state == TASK_KILLABLE && |
| fatal_signal_pending(current))) { |
| timeout = -ERESTARTSYS; |
| break; |
| } |
| __set_current_state(state); |
| spin_unlock_irq(&x->wait.lock); |
| timeout = schedule_timeout(timeout); |
| spin_lock_irq(&x->wait.lock); |
| } while (!x->done && timeout); |
| __remove_wait_queue(&x->wait, &wait); |
| if (!x->done) |
| return timeout; |
| } |
| x->done--; |
| return timeout ?: 1; |
| } |
| |
| static long __sched |
| wait_for_common(struct completion *x, long timeout, int state) |
| { |
| might_sleep(); |
| |
| spin_lock_irq(&x->wait.lock); |
| timeout = do_wait_for_common(x, timeout, state); |
| spin_unlock_irq(&x->wait.lock); |
| return timeout; |
| } |
| |
| void __sched wait_for_completion(struct completion *x) |
| { |
| wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_UNINTERRUPTIBLE); |
| } |
| EXPORT_SYMBOL(wait_for_completion); |
| |
| unsigned long __sched |
| wait_for_completion_timeout(struct completion *x, unsigned long timeout) |
| { |
| return wait_for_common(x, timeout, TASK_UNINTERRUPTIBLE); |
| } |
| EXPORT_SYMBOL(wait_for_completion_timeout); |
| |
| int __sched wait_for_completion_interruptible(struct completion *x) |
| { |
| long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_INTERRUPTIBLE); |
| if (t == -ERESTARTSYS) |
| return t; |
| return 0; |
| } |
| EXPORT_SYMBOL(wait_for_completion_interruptible); |
| |
| unsigned long __sched |
| wait_for_completion_interruptible_timeout(struct completion *x, |
| unsigned long timeout) |
| { |
| return wait_for_common(x, timeout, TASK_INTERRUPTIBLE); |
| } |
| EXPORT_SYMBOL(wait_for_completion_interruptible_timeout); |
| |
| int __sched wait_for_completion_killable(struct completion *x) |
| { |
| long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE); |
| if (t == -ERESTARTSYS) |
| return t; |
| return 0; |
| } |
| EXPORT_SYMBOL(wait_for_completion_killable); |
| |
| static long __sched |
| sleep_on_common(wait_queue_head_t *q, int state, long timeout) |
| { |
| unsigned long flags; |
| wait_queue_t wait; |
| |
| init_waitqueue_entry(&wait, current); |
| |
| __set_current_state(state); |
| |
| spin_lock_irqsave(&q->lock, flags); |
| __add_wait_queue(q, &wait); |
| spin_unlock(&q->lock); |
| timeout = schedule_timeout(timeout); |
| spin_lock_irq(&q->lock); |
| __remove_wait_queue(q, &wait); |
| spin_unlock_irqrestore(&q->lock, flags); |
| |
| return timeout; |
| } |
| |
| void __sched interruptible_sleep_on(wait_queue_head_t *q) |
| { |
| sleep_on_common(q, TASK_INTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
| } |
| EXPORT_SYMBOL(interruptible_sleep_on); |
| |
| long __sched |
| interruptible_sleep_on_timeout(wait_queue_head_t *q, long timeout) |
| { |
| return sleep_on_common(q, TASK_INTERRUPTIBLE, timeout); |
| } |
| EXPORT_SYMBOL(interruptible_sleep_on_timeout); |
| |
| void __sched sleep_on(wait_queue_head_t *q) |
| { |
| sleep_on_common(q, TASK_UNINTERRUPTIBLE, MAX_SCHEDULE_TIMEOUT); |
| } |
| EXPORT_SYMBOL(sleep_on); |
| |
| long __sched sleep_on_timeout(wait_queue_head_t *q, long timeout) |
| { |
| return sleep_on_common(q, TASK_UNINTERRUPTIBLE, timeout); |
| } |
| EXPORT_SYMBOL(sleep_on_timeout); |
| |
| #ifdef CONFIG_RT_MUTEXES |
| |
| /* |
| * rt_mutex_setprio - set the current priority of a task |
| * @p: task |
| * @prio: prio value (kernel-internal form) |
| * |
| * This function changes the 'effective' priority of a task. It does |
| * not touch ->normal_prio like __setscheduler(). |
| * |
| * Used by the rt_mutex code to implement priority inheritance logic. |
| */ |
| void rt_mutex_setprio(struct task_struct *p, int prio) |
| { |
| unsigned long flags; |
| int oldprio, on_rq, running; |
| struct rq *rq; |
| const struct sched_class *prev_class = p->sched_class; |
| |
| BUG_ON(prio < 0 || prio > MAX_PRIO); |
| |
| rq = task_rq_lock(p, &flags); |
| update_rq_clock(rq); |
| |
| oldprio = p->prio; |
| on_rq = p->se.on_rq; |
| running = task_current(rq, p); |
| if (on_rq) |
| dequeue_task(rq, p, 0); |
| if (running) |
| p->sched_class->put_prev_task(rq, p); |
| |
| if (rt_prio(prio)) |
| p->sched_class = &rt_sched_class; |
| else |
| p->sched_class = &fair_sched_class; |
| |
| p->prio = prio; |
| |
| if (running) |
| p->sched_class->set_curr_task(rq); |
| if (on_rq) { |
| enqueue_task(rq, p, 0); |
| |
| check_class_changed(rq, p, prev_class, oldprio, running); |
| } |
| task_rq_unlock(rq, &flags); |
| } |
| |
| #endif |
| |
| void set_user_nice(struct task_struct *p, long nice) |
| { |
| int old_prio, delta, on_rq; |
| unsigned long flags; |
| struct rq *rq; |
| |
| if (TASK_NICE(p) == nice || nice < -20 || nice > 19) |
| return; |
| /* |
| * We have to be careful, if called from sys_setpriority(), |
| * the task might be in the middle of scheduling on another CPU. |
| */ |
| rq = task_rq_lock(p, &flags); |
| update_rq_clock(rq); |
| /* |
| * The RT priorities are set via sched_setscheduler(), but we still |
| * allow the 'normal' nice value to be set - but as expected |
| * it wont have any effect on scheduling until the task is |
| * SCHED_FIFO/SCHED_RR: |
| */ |
| if (task_has_rt_policy(p)) { |
| p->static_prio = NICE_TO_PRIO(nice); |
| goto out_unlock; |
| } |
| on_rq = p->se.on_rq; |
| if (on_rq) |
| dequeue_task(rq, p, 0); |
| |
| p->static_prio = NICE_TO_PRIO(nice); |
| set_load_weight(p); |
| old_prio = p->prio; |
| p->prio = effective_prio(p); |
| delta = p->prio - old_prio; |
| |
| if (on_rq) { |
| enqueue_task(rq, p, 0); |
| /* |
| * If the task increased its priority or is running and |
| * lowered its priority, then reschedule its CPU: |
| */ |
| if (delta < 0 || (delta > 0 && task_running(rq, p))) |
| resched_task(rq->curr); |
| } |
| out_unlock: |
| task_rq_unlock(rq, &flags); |
| } |
| EXPORT_SYMBOL(set_user_nice); |
| |
| /* |
| * can_nice - check if a task can reduce its nice value |
| * @p: task |
| * @nice: nice value |
| */ |
| int can_nice(const struct task_struct *p, const int nice) |
| { |
| /* convert nice value [19,-20] to rlimit style value [1,40] */ |
| int nice_rlim = 20 - nice; |
| |
| return (nice_rlim <= p->signal->rlim[RLIMIT_NICE].rlim_cur || |
| capable(CAP_SYS_NICE)); |
| } |
| |
| #ifdef __ARCH_WANT_SYS_NICE |
| |
| /* |
| * sys_nice - change the priority of the current process. |
| * @increment: priority increment |
| * |
| * sys_setpriority is a more generic, but much slower function that |
| * does similar things. |
| */ |
| asmlinkage long sys_nice(int increment) |
| { |
| long nice, retval; |
| |
| /* |
| * Setpriority might change our priority at the same moment. |
| * We don't have to worry. Conceptually one call occurs first |
| * and we have a single winner. |
| */ |
| if (increment < -40) |
| increment = -40; |
| if (increment > 40) |
| increment = 40; |
| |
| nice = PRIO_TO_NICE(current->static_prio) + increment; |
| if (nice < -20) |
| nice = -20; |
| if (nice > 19) |
| nice = 19; |
| |
| if (increment < 0 && !can_nice(current, nice)) |
| return -EPERM; |
| |
| retval = security_task_setnice(current, nice); |
| if (retval) |
| return retval; |
| |
| set_user_nice(current, nice); |
| return 0; |
| } |
| |
| #endif |
| |
| /** |
| * task_prio - return the priority value of a given task. |
| * @p: the task in question. |
| * |
| * This is the priority value as seen by users in /proc. |
| * RT tasks are offset by -200. Normal tasks are centered |
| * around 0, value goes from -16 to +15. |
| */ |
| int task_prio(const struct task_struct *p) |
| { |
| return p->prio - MAX_RT_PRIO; |
| } |
| |
| /** |
| * task_nice - return the nice value of a given task. |
| * @p: the task in question. |
| */ |
| int task_nice(const struct task_struct *p) |
| { |
| return TASK_NICE(p); |
| } |
| EXPORT_SYMBOL(task_nice); |
| |
| /** |
| * idle_cpu - is a given cpu idle currently? |
| * @cpu: the processor in question. |
| */ |
| int idle_cpu(int cpu) |
| { |
| return cpu_curr(cpu) == cpu_rq(cpu)->idle; |
| } |
| |
| /** |
| * idle_task - return the idle task for a given cpu. |
| * @cpu: the processor in question. |
| */ |
| struct task_struct *idle_task(int cpu) |
| { |
| return cpu_rq(cpu)->idle; |
| } |
| |
| /** |
| * find_process_by_pid - find a process with a matching PID value. |
| * @pid: the pid in question. |
| */ |
| static struct task_struct *find_process_by_pid(pid_t pid) |
| { |
| return pid ? find_task_by_vpid(pid) : current; |
| } |
| |
| /* Actually do priority change: must hold rq lock. */ |
| static void |
| __setscheduler(struct rq *rq, struct task_struct *p, int policy, int prio) |
| { |
| BUG_ON(p->se.on_rq); |
| |
| p->policy = policy; |
| switch (p->policy) { |
| case SCHED_NORMAL: |
| case SCHED_BATCH: |
| case SCHED_IDLE: |
| p->sched_class = &fair_sched_class; |
| break; |
| case SCHED_FIFO: |
| case SCHED_RR: |
| p->sched_class = &rt_sched_class; |
| break; |
| } |
| |
| p->rt_priority = prio; |
| p->normal_prio = normal_prio(p); |
| /* we are holding p->pi_lock already */ |
| p->prio = rt_mutex_getprio(p); |
| set_load_weight(p); |
| } |
| |
| static int __sched_setscheduler(struct task_struct *p, int policy, |
| struct sched_param *param, bool user) |
| { |
| int retval, oldprio, oldpolicy = -1, on_rq, running; |
| unsigned long flags; |
| const struct sched_class *prev_class = p->sched_class; |
| struct rq *rq; |
| |
| /* may grab non-irq protected spin_locks */ |
| BUG_ON(in_interrupt()); |
| recheck: |
| /* double check policy once rq lock held */ |
| if (policy < 0) |
| policy = oldpolicy = p->policy; |
| else if (policy != SCHED_FIFO && policy != SCHED_RR && |
| policy != SCHED_NORMAL && policy != SCHED_BATCH && |
| policy != SCHED_IDLE) |
| return -EINVAL; |
| /* |
| * Valid priorities for SCHED_FIFO and SCHED_RR are |
| * 1..MAX_USER_RT_PRIO-1, valid priority for SCHED_NORMAL, |
| * SCHED_BATCH and SCHED_IDLE is 0. |
| */ |
| if (param->sched_priority < 0 || |
| (p->mm && param->sched_priority > MAX_USER_RT_PRIO-1) || |
| (!p->mm && param->sched_priority > MAX_RT_PRIO-1)) |
| return -EINVAL; |
| if (rt_policy(policy) != (param->sched_priority != 0)) |
| return -EINVAL; |
| |
| /* |
| * Allow unprivileged RT tasks to decrease priority: |
| */ |
| if (user && !capable(CAP_SYS_NICE)) { |
| if (rt_policy(policy)) { |
| unsigned long rlim_rtprio; |
| |
| if (!lock_task_sighand(p, &flags)) |
| return -ESRCH; |
| rlim_rtprio = p->signal->rlim[RLIMIT_RTPRIO].rlim_cur; |
| unlock_task_sighand(p, &flags); |
| |
| /* can't set/change the rt policy */ |
| if (policy != p->policy && !rlim_rtprio) |
| return -EPERM; |
| |
| /* can't increase priority */ |
| if (param->sched_priority > p->rt_priority && |
| param->sched_priority > rlim_rtprio) |
| return -EPERM; |
| } |
| /* |
| * Like positive nice levels, dont allow tasks to |
| * move out of SCHED_IDLE either: |
| */ |
| if (p->policy == SCHED_IDLE && policy != SCHED_IDLE) |
| return -EPERM; |
| |
| /* can't change other user's priorities */ |
| if ((current->euid != p->euid) && |
| (current->euid != p->uid)) |
| return -EPERM; |
| } |
| |
| #ifdef CONFIG_RT_GROUP_SCHED |
| /* |
| * Do not allow realtime tasks into groups that have no runtime |
| * assigned. |
| */ |
| if (user |
| && rt_policy(policy) && task_group(p)->rt_bandwidth.rt_runtime == 0) |
| return -EPERM; |
| #endif |
| |
| retval = security_task_setscheduler(p, policy, param); |
| if (retval) |
| return retval; |
| /* |
| * make sure no PI-waiters arrive (or leave) while we are |
| * changing the priority of the task: |
| */ |
| spin_lock_irqsave(&p->pi_lock, flags); |
| /* |
| * To be able to change p->policy safely, the apropriate |
| * runqueue lock must be held. |
| */ |
| rq = __task_rq_lock(p); |
| /* recheck policy now with rq lock held */ |
| if (unlikely(oldpolicy != -1 && oldpolicy != p->policy)) { |
| policy = oldpolicy = -1; |
| __task_rq_unlock(rq); |
| spin_unlock_irqrestore(&p->pi_lock, flags); |
| goto recheck; |
| } |
| update_rq_clock(rq); |
| on_rq = p->se.on_rq; |
| running = task_current(rq, p); |
| if (on_rq) |
| deactivate_task(rq, p, 0); |
| if (running) |
| p->sched_class->put_prev_task(rq, p); |
| |
| oldprio = p->prio; |
| __setscheduler(rq, p, policy, param->sched_priority); |
| |
| if (running) |
| p->sched_class->set_curr_task(rq); |
| if (on_rq) { |
| activate_task(rq, p, 0); |
| |
| check_class_changed(rq, p, prev_class, oldprio, running); |
| } |
| __task_rq_unlock(rq); |
| spin_unlock_irqrestore(&p->pi_lock, flags); |
| |
| rt_mutex_adjust_pi(p); |
| |
| return 0; |
| } |
| |
| /** |
| * sched_setscheduler - change the scheduling policy and/or RT priority of a thread. |
| * @p: the task in question. |
| * @policy: new policy. |
| * @param: structure containing the new RT priority. |
| * |
| * NOTE that the task may be already dead. |
| */ |
| int sched_setscheduler(struct task_struct *p, int policy, |
| struct sched_param *param) |
| { |
| return __sched_setscheduler(p, policy, param, true); |
| } |
| EXPORT_SYMBOL_GPL(sched_setscheduler); |
| |
| /** |
| * sched_setscheduler_nocheck - change the scheduling policy and/or RT priority of a thread from kernelspace. |
| * @p: the task in question. |
| * @policy: new policy. |
| * @param: structure containing the new RT priority. |
| * |
| * Just like sched_setscheduler, only don't bother checking if the |
| * current context has permission. For example, this is needed in |
| * stop_machine(): we create temporary high priority worker threads, |
| * but our caller might not have that capability. |
| */ |
| int sched_setscheduler_nocheck(struct task_struct *p, int policy, |
| struct sched_param *param) |
| { |
| return __sched_setscheduler(p, policy, param, false); |
| } |
| |
| static int |
| do_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) |
| { |
| struct sched_param lparam; |
| struct task_struct *p; |
| int retval; |
| |
| if (!param || pid < 0) |
| return -EINVAL; |
| if (copy_from_user(&lparam, param, sizeof(struct sched_param))) |
| return -EFAULT; |
| |
| rcu_read_lock(); |
| retval = -ESRCH; |
| p = find_process_by_pid(pid); |
| if (p != NULL) |
| retval = sched_setscheduler(p, policy, &lparam); |
| rcu_read_unlock(); |
| |
| return retval; |
| } |
| |
| /** |
| * sys_sched_setscheduler - set/change the scheduler policy and RT priority |
| * @pid: the pid in question. |
| * @policy: new policy. |
| * @param: structure containing the new RT priority. |
| */ |
| asmlinkage long |
| sys_sched_setscheduler(pid_t pid, int policy, struct sched_param __user *param) |
| { |
| /* negative values for policy are not valid */ |
| if (policy < 0) |
| return -EINVAL; |
| |
| return do_sched_setscheduler(pid, policy, param); |
| } |
| |
| /** |
| * sys_sched_setparam - set/change the RT priority of a thread |
| * @pid: the pid in question. |
| * @param: structure containing the new RT priority. |
| */ |
| asmlinkage long sys_sched_setparam(pid_t pid, struct sched_param __user *param) |
| { |
| return do_sched_setscheduler(pid, -1, param); |
| } |
| |
| /** |
| * sys_sched_getscheduler - get the policy (scheduling class) of a thread |
| * @pid: the pid in question. |
| */ |
| asmlinkage long sys_sched_getscheduler(pid_t pid) |
| { |
| struct task_struct *p; |
| int retval; |
| |
| if (pid < 0) |
| return -EINVAL; |
| |
| retval = -ESRCH; |
| read_lock(&tasklist_lock); |
| p = find_process_by_pid(pid); |
| if (p) { |
| retval = security_task_getscheduler(p); |
| if (!retval) |
| retval = p->policy; |
| } |
| read_unlock(&tasklist_lock); |
| return retval; |
| } |
| |
| /** |
| * sys_sched_getscheduler - get the RT priority of a thread |
| * @pid: the pid in question. |
| * @param: structure containing the RT priority. |
| */ |
| asmlinkage long sys_sched_getparam(pid_t pid, struct sched_param __user *param) |
| { |
| struct sched_param lp; |
| struct task_struct *p; |
| int retval; |
| |
| if (!param || pid < 0) |
| return -EINVAL; |
| |
| read_lock(&tasklist_lock); |
| p = find_process_by_pid(pid); |
| retval = -ESRCH; |
| if (!p) |
| goto out_unlock; |
| |
| retval = security_task_getscheduler(p); |
| if (retval) |
| goto out_unlock; |
| |
| lp.sched_priority = p->rt_priority; |
| read_unlock(&tasklist_lock); |
| |
| /* |
| * This one might sleep, we cannot do it with a spinlock held ... |
| */ |
| retval = copy_to_user(param, &lp, sizeof(*param)) ? -EFAULT : 0; |
| |
| return retval; |
| |
| out_unlock: |
| read_unlock(&tasklist_lock); |
| return retval; |
| } |
| |
| long sched_setaffinity(pid_t pid, const cpumask_t *in_mask) |
| { |
| cpumask_t cpus_allowed; |
| cpumask_t new_mask = *in_mask; |
| struct task_struct *p; |
| int retval; |
| |
| get_online_cpus(); |
| read_lock(&tasklist_lock); |
| |
| p = find_process_by_pid(pid); |
| if (!p) { |
| read_unlock(&tasklist_lock); |
| put_online_cpus(); |
| return -ESRCH; |
| } |
| |
| /* |
| * It is not safe to call set_cpus_allowed with the |
| * tasklist_lock held. We will bump the task_struct's |
| * usage count and then drop tasklist_lock. |
| */ |
| get_task_struct(p); |
| read_unlock(&tasklist_lock); |
| |
| retval = -EPERM; |
| if ((current->euid != p->euid) && (current->euid != p->uid) && |
| !capable(CAP_SYS_NICE)) |
| goto out_unlock; |
| |
| retval = security_task_setscheduler(p, 0, NULL); |
| if (retval) |
| goto out_unlock; |
| |
| cpuset_cpus_allowed(p, &cpus_allowed); |
| cpus_and(new_mask, new_mask, cpus_allowed); |
| again: |
| retval = set_cpus_allowed_ptr(p, &new_mask); |
| |
| if (!retval) { |
| cpuset_cpus_allowed(p, &cpus_allowed); |
| if (!cpus_subset(new_mask, cpus_allowed)) { |
| /* |
| * We must have raced with a concurrent cpuset |
| * update. Just reset the cpus_allowed to the |
| * cpuset's cpus_allowed |
| */ |
| new_mask = cpus_allowed; |
| goto again; |
| } |
| } |
| out_unlock: |
| put_task_struct(p); |
| put_online_cpus(); |
| return retval; |
| } |
| |
| static int get_user_cpu_mask(unsigned long __user *user_mask_ptr, unsigned len, |
| cpumask_t *new_mask) |
| { |
| if (len < sizeof(cpumask_t)) { |
| memset(new_mask, 0, sizeof(cpumask_t)); |
| } else if (len > sizeof(cpumask_t)) { |
| len = sizeof(cpumask_t); |
| } |
| return copy_from_user(new_mask, user_mask_ptr, len) ? -EFAULT : 0; |
| } |
| |
| /** |
| * sys_sched_setaffinity - set the cpu affinity of a process |
| * @pid: pid of the process |
| * @len: length in bytes of the bitmask pointed to by user_mask_ptr |
| * @user_mask_ptr: user-space pointer to the new cpu mask |
| */ |
| asmlinkage long sys_sched_setaffinity(pid_t pid, unsigned int len, |
| unsigned long __user *user_mask_ptr) |
| { |
| cpumask_t new_mask; |
| int retval; |
| |
| retval = get_user_cpu_mask(user_mask_ptr, len, &new_mask); |
| if (retval) |
| return retval; |
| |
| return sched_setaffinity(pid, &new_mask); |
| } |
| |
| long sched_getaffinity(pid_t pid, cpumask_t *mask) |
| { |
| struct task_struct *p; |
| int retval; |
| |
| get_online_cpus(); |
| read_lock(&tasklist_lock); |
| |
| retval = -ESRCH; |
| p = find_process_by_pid(pid); |
| if (!p) |
| goto out_unlock; |
| |
| retval = security_task_getscheduler(p); |
| if (retval) |
| goto out_unlock; |
| |
| cpus_and(*mask, p->cpus_allowed, cpu_online_map); |
| |
| out_unlock: |
| read_unlock(&tasklist_lock); |
| put_online_cpus(); |
| |
| return retval; |
| } |
| |
| /** |
| * sys_sched_getaffinity - get the cpu affinity of a process |
| * @pid: pid of the process |
| * @len: length in bytes of the bitmask pointed to by user_mask_ptr |
| * @user_mask_ptr: user-space pointer to hold the current cpu mask |
| */ |
| asmlinkage long sys_sched_getaffinity(pid_t pid, unsigned int len, |
| unsigned long __user *user_mask_ptr) |
| { |
| int ret; |
| cpumask_t mask; |
| |
| if (len < sizeof(cpumask_t)) |
| return -EINVAL; |
| |
| ret = sched_getaffinity(pid, &mask); |
| if (ret < 0) |
| return ret; |
| |
| if (copy_to_user(user_mask_ptr, &mask, sizeof(cpumask_t))) |
| return -EFAULT; |
| |
| return sizeof(cpumask_t); |
| } |
| |
| /** |
| * sys_sched_yield - yield the current processor to other threads. |
| * |
| * This function yields the current CPU to other tasks. If there are no |
| * other threads running on this CPU then this function will return. |
| */ |
| asmlinkage long sys_sched_yield(void) |
| { |
| struct rq *rq = this_rq_lock(); |
| |
| schedstat_inc(rq, yld_count); |
| current->sched_class->yield_task(rq); |
| |
| /* |
| * Since we are going to call schedule() anyway, there's |
| * no need to preempt or enable interrupts: |
| */ |
| __release(rq->lock); |
| spin_release(&rq->lock.dep_map, 1, _THIS_IP_); |
| _raw_spin_unlock(&rq->lock); |
| preempt_enable_no_resched(); |
| |
| schedule(); |
| |
| return 0; |
| } |
| |
| static void __cond_resched(void) |
| { |
| #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP |
| __might_sleep(__FILE__, __LINE__); |
| #endif |
| /* |
| * The BKS might be reacquired before we have dropped |
| * PREEMPT_ACTIVE, which could trigger a second |
| * cond_resched() call. |
| */ |
| do { |
| add_preempt_count(PREEMPT_ACTIVE); |
| schedule(); |
| sub_preempt_count(PREEMPT_ACTIVE); |
| } while (need_resched()); |
| } |
| |
| int __sched _cond_resched(void) |
| { |
| if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) && |
| system_state == SYSTEM_RUNNING) { |
| __cond_resched(); |
| return 1; |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL(_cond_resched); |
| |
| /* |
| * cond_resched_lock() - if a reschedule is pending, drop the given lock, |
| * call schedule, and on return reacquire the lock. |
| * |
| * This works OK both with and without CONFIG_PREEMPT. We do strange low-level |
| * operations here to prevent schedule() from being called twice (once via |
| * spin_unlock(), once by hand). |
| */ |
| int cond_resched_lock(spinlock_t *lock) |
| { |
| int resched = need_resched() && system_state == SYSTEM_RUNNING; |
| int ret = 0; |
| |
| if (spin_needbreak(lock) || resched) { |
| spin_unlock(lock); |
| if (resched && need_resched()) |
| __cond_resched(); |
| else |
| cpu_relax(); |
| ret = 1; |
| spin_lock(lock); |
| } |
| return ret; |
| } |
| EXPORT_SYMBOL(cond_resched_lock); |
| |
| int __sched cond_resched_softirq(void) |
| { |
| BUG_ON(!in_softirq()); |
| |
| if (need_resched() && system_state == SYSTEM_RUNNING) { |
| local_bh_enable(); |
| __cond_resched(); |
| local_bh_disable(); |
| return 1; |
| } |
| return 0; |
| } |
| EXPORT_SYMBOL(cond_resched_softirq); |
| |
| /** |
| * yield - yield the current processor to other threads. |
| * |
| * This is a shortcut for kernel-space yielding - it marks the |
| * thread runnable and calls sys_sched_yield(). |
| */ |
| void __sched yield(void) |
| { |
| set_current_state(TASK_RUNNING); |
| sys_sched_yield(); |
| } |
| EXPORT_SYMBOL(yield); |
| |
| /* |
| * This task is about to go to sleep on IO. Increment rq->nr_iowait so |
| * that process accounting knows that this is a task in IO wait state. |
| * |
| * But don't do that if it is a deliberate, throttling IO wait (this task |
| * has set its backing_dev_info: the queue against which it should throttle) |
| */ |
| void __sched io_schedule(void) |
| { |
| struct rq *rq = &__raw_get_cpu_var(runqueues); |
| |
| delayacct_blkio_start(); |
| atomic_inc(&rq->nr_iowait); |
| schedule(); |
| atomic_dec(&rq->nr_iowait); |
| delayacct_blkio_end(); |
| } |
| EXPORT_SYMBOL(io_schedule); |
| |
| long __sched io_schedule_timeout(long timeout) |
| { |
| struct rq *rq = &__raw_get_cpu_var(runqueues); |
| long ret; |
| |
| delayacct_blkio_start(); |
| atomic_inc(&rq->nr_iowait); |
| ret = schedule_timeout(timeout); |
| atomic_dec(&rq->nr_iowait); |
| delayacct_blkio_end(); |
| return ret; |
| } |
| |
| /** |
| * sys_sched_get_priority_max - return maximum RT priority. |
| * @policy: scheduling class. |
| * |
| * this syscall returns the maximum rt_priority that can be used |
| * by a given scheduling class. |
| */ |
| asmlinkage long sys_sched_get_priority_max(int policy) |
| { |
| int ret = -EINVAL; |
| |
| switch (policy) { |
| case SCHED_FIFO: |
| case SCHED_RR: |
| ret = MAX_USER_RT_PRIO-1; |
| break; |
| case SCHED_NORMAL: |
| case SCHED_BATCH: |
| case SCHED_IDLE: |
| ret = 0; |
| break; |
| } |
| return ret; |
| } |
| |
| /** |
| * sys_sched_get_priority_min - return minimum RT priority. |
| * @policy: scheduling class. |
| * |
| * this syscall returns the minimum rt_priority that can be used |
| * by a given scheduling class. |
| */ |
| asmlinkage long sys_sched_get_priority_min(int policy) |
| { |
| int ret = -EINVAL; |
| |
| switch (policy) { |
| case SCHED_FIFO: |
| case SCHED_RR: |
| ret = 1; |
| break; |
| case SCHED_NORMAL: |
| case SCHED_BATCH: |
| case SCHED_IDLE: |
| ret = 0; |
| } |
| return ret; |
| } |
| |
| /** |
| * sys_sched_rr_get_interval - return the default timeslice of a process. |
| * @pid: pid of the process. |
| * @interval: userspace pointer to the timeslice value. |
| * |
| * this syscall writes the default timeslice value of a given process |
| * into the user-space timespec buffer. A value of '0' means infinity. |
| */ |
| asmlinkage |
| long sys_sched_rr_get_interval(pid_t pid, struct timespec __user *interval) |
| { |
| struct task_struct *p; |
| unsigned int time_slice; |
| int retval; |
| struct timespec t; |
| |
| if (pid < 0) |
| return -EINVAL; |
| |
| retval = -ESRCH; |
| read_lock(&tasklist_lock); |
| p = find_process_by_pid(pid); |
| if (!p) |
| goto out_unlock; |
| |
| retval = security_task_getscheduler(p); |
| if (retval) |
| goto out_unlock; |
| |
| /* |
| * Time slice is 0 for SCHED_FIFO tasks and for SCHED_OTHER |
| * tasks that are on an otherwise idle runqueue: |
| */ |
| time_slice = 0; |
| if (p->policy == SCHED_RR) { |
| time_slice = DEF_TIMESLICE; |
| } else if (p->policy != SCHED_FIFO) { |
| struct sched_entity *se = &p->se; |
| unsigned long flags; |
| struct rq *rq; |
| |
| rq = task_rq_lock(p, &flags); |
| if (rq->cfs.load.weight) |
| time_slice = NS_TO_JIFFIES(sched_slice(&rq->cfs, se)); |
| task_rq_unlock(rq, &flags); |
| } |
| read_unlock(&tasklist_lock); |
| jiffies_to_timespec(time_slice, &t); |
| retval = copy_to_user(interval, &t, sizeof(t)) ? -EFAULT : 0; |
| return retval; |
| |
| out_unlock: |
| read_unlock(&tasklist_lock); |
| return retval; |
| } |
| |
| static const char stat_nam[] = TASK_STATE_TO_CHAR_STR; |
| |
| void sched_show_task(struct task_struct *p) |
| { |
| unsigned long free = 0; |
| unsigned state; |
| |
| state = p->state ? __ffs(p->state) + 1 : 0; |
| printk(KERN_INFO "%-13.13s %c", p->comm, |
| state < sizeof(stat_nam) - 1 ? stat_nam[state] : '?'); |
| #if BITS_PER_LONG == 32 |
| if (state == TASK_RUNNING) |
| printk(KERN_CONT " running "); |
| else |
| printk(KERN_CONT " %08lx ", thread_saved_pc(p)); |
| #else |
| if (state == TASK_RUNNING) |
| printk(KERN_CONT " running task "); |
| else |
| printk(KERN_CONT " %016lx ", thread_saved_pc(p)); |
| #endif |
| #ifdef CONFIG_DEBUG_STACK_USAGE |
| { |
| unsigned long *n = end_of_stack(p); |
| while (!*n) |
| n++; |
| free = (unsigned long)n - (unsigned long)end_of_stack(p); |
| } |
| #endif |
| printk(KERN_CONT "%5lu %5d %6d\n", free, |
| task_pid_nr(p), task_pid_nr(p->real_parent)); |
| |
| show_stack(p, NULL); |
| } |
| |
| void show_state_filter(unsigned long state_filter) |
| { |
| struct task_struct *g, *p; |
| |
| #if BITS_PER_LONG == 32 |
| printk(KERN_INFO |
| " task PC stack pid father\n"); |
| #else |
| printk(KERN_INFO |
| " task PC stack pid father\n"); |
| #endif |
| read_lock(&tasklist_lock); |
| do_each_thread(g, p) { |
| /* |
| * reset the NMI-timeout, listing all files on a slow |
| * console might take alot of time: |
| */ |
| touch_nmi_watchdog(); |
| if (!state_filter || (p->state & state_filter)) |
| sched_show_task(p); |
| } while_each_thread(g, p); |
| |
| touch_all_softlockup_watchdogs(); |
| |
| #ifdef CONFIG_SCHED_DEBUG |
| sysrq_sched_debug_show(); |
| #endif |
| read_unlock(&tasklist_lock); |
| /* |
| * Only show locks if all tasks are dumped: |
| */ |
| if (state_filter == -1) |
| debug_show_all_locks(); |
| } |
| |
| void __cpuinit init_idle_bootup_task(struct task_struct *idle) |
| { |
| idle->sched_class = &idle_sched_class; |
| } |
| |
| /** |
| * init_idle - set up an idle thread for a given CPU |
| * @idle: task in question |
| * @cpu: cpu the idle task belongs to |
| * |
| * NOTE: this function does not set the idle thread's NEED_RESCHED |
| * flag, to make booting more robust. |
| */ |
| void __cpuinit init_idle(struct task_struct *idle, int cpu) |
| { |
| struct rq *rq = cpu_rq(cpu); |
| unsigned long flags; |
| |
| __sched_fork(idle); |
| idle->se.exec_start = sched_clock(); |
| |
| idle->prio = idle->normal_prio = MAX_PRIO; |
| idle->cpus_allowed = cpumask_of_cpu(cpu); |
| __set_task_cpu(idle, cpu); |
| |
| spin_lock_irqsave(&rq->lock, flags); |
| rq->curr = rq->idle = idle; |
| #if defined(CONFIG_SMP) && defined(__ARCH_WANT_UNLOCKED_CTXSW) |
| idle->oncpu = 1; |
| #endif |
| spin_unlock_irqrestore(&rq->lock, flags); |
| |
| /* Set the preempt count _outside_ the spinlocks! */ |
| #if defined(CONFIG_PREEMPT) |
| task_thread_info(idle)->preempt_count = (idle->lock_depth >= 0); |
| #else |
| task_thread_info(idle)->preempt_count = 0; |
| #endif |
| /* |
| * The idle tasks have their own, simple scheduling class: |
| */ |
| idle->sched_class = &idle_sched_class; |
| } |
| |
| /* |
| * In a system that switches off the HZ timer nohz_cpu_mask |
| * indicates which cpus entered this state. This is used |
| * in the rcu update to wait only for active cpus. For system |
| * which do not switch off the HZ timer nohz_cpu_mask should |
| * always be CPU_MASK_NONE. |
| */ |
| cpumask_t nohz_cpu_mask = CPU_MASK_NONE; |
| |
| /* |
| * Increase the granularity value when there are more CPUs, |
| * because with more CPUs the 'effective latency' as visible |
| * to users decreases. But the relationship is not linear, |
| * so pick a second-best guess by going with the log2 of the |
| * number of CPUs. |
| * |
| * This idea comes from the SD scheduler of Con Kolivas: |
| */ |
| static inline void sched_init_granularity(void) |
| { |
| unsigned int factor = 1 + ilog2(num_online_cpus()); |
| const unsigned long limit = 200000000; |
| |
| sysctl_sched_min_granularity *= factor; |
| if (sysctl_sched_min_granularity > limit) |
| sysctl_sched_min_granularity = limit; |
| |
| sysctl_sched_latency *= factor; |
| if (sysctl_sched_latency > limit) |
| sysctl_sched_latency = limit; |
| |
| sysctl_sched_wakeup_granularity *= factor; |
| } |
| |
| #ifdef CONFIG_SMP |
| /* |
| * This is how migration works: |
| * |
| * 1) we queue a struct migration_req structure in the source CPU's |
| * runqueue and wake up that CPU's migration thread. |
| * 2) we down() the locked semaphore => thread blocks. |
| * 3) migration thread wakes up (implicitly it forces the migrated |
| * thread off the CPU) |
| * 4) it gets the migration request and checks whether the migrated |
| * task is still in the wrong runqueue. |
| * 5) if it's in the wrong runqueue then the migration thread removes |
| * it and puts it into the right queue. |
| * 6) migration thread up()s the semaphore. |
| * 7) we wake up and the migration is done. |
| */ |
| |
| /* |
| * Change a given task's CPU affinity. Migrate the thread to a |
| * proper CPU and schedule it away if the CPU it's executing on |
| * is removed from the allowed bitmask. |
| * |
| * NOTE: the caller must have a valid reference to the task, the |
| * task must not exit() & deallocate itself prematurely. The |
| * call is not atomic; no spinlocks may be held. |
| */ |
| int set_cpus_allowed_ptr(struct task_struct *p, const cpumask_t *new_mask) |
| { |
| struct migration_req req; |
| unsigned long flags; |
| struct rq *rq; |
| int ret = 0; |
| |
| rq = task_rq_lock(p, &flags); |
| if (!cpus_intersects(*new_mask, cpu_online_map)) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| if (unlikely((p->flags & PF_THREAD_BOUND) && p != current && |
| !cpus_equal(p->cpus_allowed, *new_mask))) { |
| ret = -EINVAL; |
| goto out; |
| } |
| |
| if (p->sched_class->set_cpus_allowed) |
| p->sched_class->set_cpus_allowed(p, new_mask); |
| else { |
| p->cpus_allowed = *new_mask; |
| p->rt.nr_cpus_allowed = cpus_weight(*new_mask); |
| } |
| |
| /* Can the task run on the task's current CPU? If so, we're done */ |
| if (cpu_isset(task_cpu(p), *new_mask)) |
| goto out; |
| |
| if (migrate_task(p, any_online_cpu(*new_mask), &req)) { |
| /* Need help from migration thread: drop lock and wait. */ |
| task_rq_unlock(rq, &flags); |
| wake_up_process(rq->migration_thread); |
| wait_for_completion(&req.done); |
| tlb_migrate_finish(p->mm); |
| return 0; |
| } |
| out: |
| task_rq_unlock(rq, &flags); |
| |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(set_cpus_allowed_ptr); |
| |
| /* |
| * Move (not current) task off this cpu, onto dest cpu. We're doing |
| * this because either it can't run here any more (set_cpus_allowed() |
| * away from this CPU, or CPU going down), or because we're |
| * attempting to rebalance this task on exec (sched_exec). |
| * |
| * So we race with normal scheduler movements, but that's OK, as long |
| * as the task is no longer on this CPU. |
| * |
| * Returns non-zero if task was successfully migrated. |
| */ |
| static int __migrate_task(struct task_struct *p, int src_cpu, int dest_cpu) |
| { |
| struct rq *rq_dest, *rq_src; |
| int ret = 0, on_rq; |
| |
| if (unlikely(cpu_is_offline(dest_cpu))) |
| return ret; |
| |
| rq_src = cpu_rq(src_cpu); |
| rq_dest = cpu_rq(dest_cpu); |
| |
| double_rq_lock(rq_src, rq_dest); |
| /* Already moved. */ |
| if (task_cpu(p) != src_cpu) |
| goto done; |
| /* Affinity changed (again). */ |
| if (!cpu_isset(dest_cpu, p->cpus_allowed)) |
| goto fail; |
| |
| on_rq = p->se.on_rq; |
| if (on_rq) |
| deactivate_task(rq_src, p, 0); |
| |
| set_task_cpu(p, dest_cpu); |
| if (on_rq) { |
| activate_task(rq_dest, p, 0); |
| check_preempt_curr(rq_dest, p); |
| } |
| done: |
| ret = 1; |
| fail: |
| double_rq_unlock(rq_src, rq_dest); |
| return ret; |
| } |
| |
| /* |
| * migration_thread - this is a highprio system thread that performs |
| * thread migration by bumping thread off CPU then 'pushing' onto |
| * another runqueue. |
| */ |
| static int migration_thread(void *data) |
| { |
| int cpu = (long)data; |
| struct rq *rq; |
| |
| rq = cpu_rq(cpu); |
| BUG_ON(rq->migration_thread != current); |
| |
| set_current_state(TASK_INTERRUPTIBLE); |
| while (!kthread_should_stop()) { |
| struct migration_req *req; |
| struct list_head *head; |
| |
| spin_lock_irq(&rq->lock); |
| |
| if (cpu_is_offline(cpu)) { |
| spin_unlock_irq(&rq->lock); |
| goto wait_to_die; |
| } |
| |
| if (rq->active_balance) { |
| active_load_balance(rq, cpu); |
| rq->active_balance = 0; |
| } |
| |
| head = &rq->migration_queue; |
| |
| if (list_empty(head)) { |
| spin_unlock_irq(&rq->lock); |
| schedule(); |
| set_current_state(TASK_INTERRUPTIBLE); |
| continue; |
| } |
| req = list_entry(head->next, struct migration_req, list); |
| list_del_init(head->next); |
| |
| spin_unlock(&rq->lock); |
| __migrate_task(req->task, cpu, req->dest_cpu); |
| local_irq_enable(); |
| |
| complete(&req->done); |
| } |
| __set_current_state(TASK_RUNNING); |
| return 0; |
| |
| wait_to_die: |
| /* Wait for kthread_stop */ |
| set_current_state(TASK_INTERRUPTIBLE); |
| while (!kthread_should_stop()) { |
| schedule(); |
| set_current_state(TASK_INTERRUPTIBLE); |
| } |
| __set_current_state(TASK_RUNNING); |
| return 0; |
| } |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| |
| static int __migrate_task_irq(struct task_struct *p, int src_cpu, int dest_cpu) |
| { |
| int ret; |
| |
| local_irq_disable(); |
| ret = __migrate_task(p, src_cpu, dest_cpu); |
| local_irq_enable(); |
| return ret; |
| } |
| |
| /* |
| * Figure out where task on dead CPU should go, use force if necessary. |
| * NOTE: interrupts should be disabled by the caller |
| */ |
| static void move_task_off_dead_cpu(int dead_cpu, struct task_struct *p) |
| { |
| unsigned long flags; |
| cpumask_t mask; |
| struct rq *rq; |
| int dest_cpu; |
| |
| do { |
| /* On same node? */ |
| mask = node_to_cpumask(cpu_to_node(dead_cpu)); |
| cpus_and(mask, mask, p->cpus_allowed); |
| dest_cpu = any_online_cpu(mask); |
| |
| /* On any allowed CPU? */ |
| if (dest_cpu >= nr_cpu_ids) |
| dest_cpu = any_online_cpu(p->cpus_allowed); |
| |
| /* No more Mr. Nice Guy. */ |
| if (dest_cpu >= nr_cpu_ids) { |
| cpumask_t cpus_allowed; |
| |
| cpuset_cpus_allowed_locked(p, &cpus_allowed); |
| /* |
| * Try to stay on the same cpuset, where the |
| * current cpuset may be a subset of all cpus. |
| * The cpuset_cpus_allowed_locked() variant of |
| * cpuset_cpus_allowed() will not block. It must be |
| * called within calls to cpuset_lock/cpuset_unlock. |
| */ |
| rq = task_rq_lock(p, &flags); |
| p->cpus_allowed = cpus_allowed; |
| dest_cpu = any_online_cpu(p->cpus_allowed); |
| task_rq_unlock(rq, &flags); |
| |
| /* |
| * Don't tell them about moving exiting tasks or |
| * kernel threads (both mm NULL), since they never |
| * leave kernel. |
| */ |
| if (p->mm && printk_ratelimit()) { |
| printk(KERN_INFO "process %d (%s) no " |
| "longer affine to cpu%d\n", |
| task_pid_nr(p), p->comm, dead_cpu); |
| } |
| } |
| } while (!__migrate_task_irq(p, dead_cpu, dest_cpu)); |
| } |
| |
| /* |
| * While a dead CPU has no uninterruptible tasks queued at this point, |
| * it might still have a nonzero ->nr_uninterruptible counter, because |
| * for performance reasons the counter is not stricly tracking tasks to |
| * their home CPUs. So we just add the counter to another CPU's counter, |
| * to keep the global sum constant after CPU-down: |
| */ |
| static void migrate_nr_uninterruptible(struct rq *rq_src) |
| { |
| struct rq *rq_dest = cpu_rq(any_online_cpu(*CPU_MASK_ALL_PTR)); |
| unsigned long flags; |
| |
| local_irq_save(flags); |
| double_rq_lock(rq_src, rq_dest); |
| rq_dest->nr_uninterruptible += rq_src->nr_uninterruptible; |
| rq_src->nr_uninterruptible = 0; |
| double_rq_unlock(rq_src, rq_dest); |
| local_irq_restore(flags); |
| } |
| |
| /* Run through task list and migrate tasks from the dead cpu. */ |
| static void migrate_live_tasks(int src_cpu) |
| { |
| struct task_struct *p, *t; |
| |
| read_lock(&tasklist_lock); |
| |
| do_each_thread(t, p) { |
| if (p == current) |
| continue; |
| |
| if (task_cpu(p) == src_cpu) |
| move_task_off_dead_cpu(src_cpu, p); |
| } while_each_thread(t, p); |
| |
| read_unlock(&tasklist_lock); |
| } |
| |
| /* |
| * Schedules idle task to be the next runnable task on current CPU. |
| * It does so by boosting its priority to highest possible. |
| * Used by CPU offline code. |
| */ |
| void sched_idle_next(void) |
| { |
| int this_cpu = smp_processor_id(); |
| struct rq *rq = cpu_rq(this_cpu); |
| struct task_struct *p = rq->idle; |
| unsigned long flags; |
| |
| /* cpu has to be offline */ |
| BUG_ON(cpu_online(this_cpu)); |
| |
| /* |
| * Strictly not necessary since rest of the CPUs are stopped by now |
| * and interrupts disabled on the current cpu. |
| */ |
| spin_lock_irqsave(&rq->lock, flags); |
| |
| __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
| |
| update_rq_clock(rq); |
| activate_task(rq, p, 0); |
| |
| spin_unlock_irqrestore(&rq->lock, flags); |
| } |
| |
| /* |
| * Ensures that the idle task is using init_mm right before its cpu goes |
| * offline. |
| */ |
| void idle_task_exit(void) |
| { |
| struct mm_struct *mm = current->active_mm; |
| |
| BUG_ON(cpu_online(smp_processor_id())); |
| |
| if (mm != &init_mm) |
| switch_mm(mm, &init_mm, current); |
| mmdrop(mm); |
| } |
| |
| /* called under rq->lock with disabled interrupts */ |
| static void migrate_dead(unsigned int dead_cpu, struct task_struct *p) |
| { |
| struct rq *rq = cpu_rq(dead_cpu); |
| |
| /* Must be exiting, otherwise would be on tasklist. */ |
| BUG_ON(!p->exit_state); |
| |
| /* Cannot have done final schedule yet: would have vanished. */ |
| BUG_ON(p->state == TASK_DEAD); |
| |
| get_task_struct(p); |
| |
| /* |
| * Drop lock around migration; if someone else moves it, |
| * that's OK. No task can be added to this CPU, so iteration is |
| * fine. |
| */ |
| spin_unlock_irq(&rq->lock); |
| move_task_off_dead_cpu(dead_cpu, p); |
| spin_lock_irq(&rq->lock); |
| |
| put_task_struct(p); |
| } |
| |
| /* release_task() removes task from tasklist, so we won't find dead tasks. */ |
| static void migrate_dead_tasks(unsigned int dead_cpu) |
| { |
| struct rq *rq = cpu_rq(dead_cpu); |
| struct task_struct *next; |
| |
| for ( ; ; ) { |
| if (!rq->nr_running) |
| break; |
| update_rq_clock(rq); |
| next = pick_next_task(rq, rq->curr); |
| if (!next) |
| break; |
| next->sched_class->put_prev_task(rq, next); |
| migrate_dead(dead_cpu, next); |
| |
| } |
| } |
| #endif /* CONFIG_HOTPLUG_CPU */ |
| |
| #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) |
| |
| static struct ctl_table sd_ctl_dir[] = { |
| { |
| .procname = "sched_domain", |
| .mode = 0555, |
| }, |
| {0, }, |
| }; |
| |
| static struct ctl_table sd_ctl_root[] = { |
| { |
| .ctl_name = CTL_KERN, |
| .procname = "kernel", |
| .mode = 0555, |
| .child = sd_ctl_dir, |
| }, |
| {0, }, |
| }; |
| |
| static struct ctl_table *sd_alloc_ctl_entry(int n) |
| { |
| struct ctl_table *entry = |
| kcalloc(n, sizeof(struct ctl_table), GFP_KERNEL); |
| |
| return entry; |
| } |
| |
| static void sd_free_ctl_entry(struct ctl_table **tablep) |
| { |
| struct ctl_table *entry; |
| |
| /* |
| * In the intermediate directories, both the child directory and |
| * procname are dynamically allocated and could fail but the mode |
| * will always be set. In the lowest directory the names are |
| * static strings and all have proc handlers. |
| */ |
| for (entry = *tablep; entry->mode; entry++) { |
| if (entry->child) |
| sd_free_ctl_entry(&entry->child); |
| if (entry->proc_handler == NULL) |
| kfree(entry->procname); |
| } |
| |
| kfree(*tablep); |
| *tablep = NULL; |
| } |
| |
| static void |
| set_table_entry(struct ctl_table *entry, |
| const char *procname, void *data, int maxlen, |
| mode_t mode, proc_handler *proc_handler) |
| { |
| entry->procname = procname; |
| entry->data = data; |
| entry->maxlen = maxlen; |
| entry->mode = mode; |
| entry->proc_handler = proc_handler; |
| } |
| |
| static struct ctl_table * |
| sd_alloc_ctl_domain_table(struct sched_domain *sd) |
| { |
| struct ctl_table *table = sd_alloc_ctl_entry(12); |
| |
| if (table == NULL) |
| return NULL; |
| |
| set_table_entry(&table[0], "min_interval", &sd->min_interval, |
| sizeof(long), 0644, proc_doulongvec_minmax); |
| set_table_entry(&table[1], "max_interval", &sd->max_interval, |
| sizeof(long), 0644, proc_doulongvec_minmax); |
| set_table_entry(&table[2], "busy_idx", &sd->busy_idx, |
| sizeof(int), 0644, proc_dointvec_minmax); |
| set_table_entry(&table[3], "idle_idx", &sd->idle_idx, |
| sizeof(int), 0644, proc_dointvec_minmax); |
| set_table_entry(&table[4], "newidle_idx", &sd->newidle_idx, |
| sizeof(int), 0644, proc_dointvec_minmax); |
| set_table_entry(&table[5], "wake_idx", &sd->wake_idx, |
| sizeof(int), 0644, proc_dointvec_minmax); |
| set_table_entry(&table[6], "forkexec_idx", &sd->forkexec_idx, |
| sizeof(int), 0644, proc_dointvec_minmax); |
| set_table_entry(&table[7], "busy_factor", &sd->busy_factor, |
| sizeof(int), 0644, proc_dointvec_minmax); |
| set_table_entry(&table[8], "imbalance_pct", &sd->imbalance_pct, |
| sizeof(int), 0644, proc_dointvec_minmax); |
| set_table_entry(&table[9], "cache_nice_tries", |
| &sd->cache_nice_tries, |
| sizeof(int), 0644, proc_dointvec_minmax); |
| set_table_entry(&table[10], "flags", &sd->flags, |
| sizeof(int), 0644, proc_dointvec_minmax); |
| /* &table[11] is terminator */ |
| |
| return table; |
| } |
| |
| static ctl_table *sd_alloc_ctl_cpu_table(int cpu) |
| { |
| struct ctl_table *entry, *table; |
| struct sched_domain *sd; |
| int domain_num = 0, i; |
| char buf[32]; |
| |
| for_each_domain(cpu, sd) |
| domain_num++; |
| entry = table = sd_alloc_ctl_entry(domain_num + 1); |
| if (table == NULL) |
| return NULL; |
| |
| i = 0; |
| for_each_domain(cpu, sd) { |
| snprintf(buf, 32, "domain%d", i); |
| entry->procname = kstrdup(buf, GFP_KERNEL); |
| entry->mode = 0555; |
| entry->child = sd_alloc_ctl_domain_table(sd); |
| entry++; |
| i++; |
| } |
| return table; |
| } |
| |
| static struct ctl_table_header *sd_sysctl_header; |
| static void register_sched_domain_sysctl(void) |
| { |
| int i, cpu_num = num_online_cpus(); |
| struct ctl_table *entry = sd_alloc_ctl_entry(cpu_num + 1); |
| char buf[32]; |
| |
| WARN_ON(sd_ctl_dir[0].child); |
| sd_ctl_dir[0].child = entry; |
| |
| if (entry == NULL) |
| return; |
| |
| for_each_online_cpu(i) { |
| snprintf(buf, 32, "cpu%d", i); |
| entry->procname = kstrdup(buf, GFP_KERNEL); |
| entry->mode = 0555; |
| entry->child = sd_alloc_ctl_cpu_table(i); |
| entry++; |
| } |
| |
| WARN_ON(sd_sysctl_header); |
| sd_sysctl_header = register_sysctl_table(sd_ctl_root); |
| } |
| |
| /* may be called multiple times per register */ |
| static void unregister_sched_domain_sysctl(void) |
| { |
| if (sd_sysctl_header) |
| unregister_sysctl_table(sd_sysctl_header); |
| sd_sysctl_header = NULL; |
| if (sd_ctl_dir[0].child) |
| sd_free_ctl_entry(&sd_ctl_dir[0].child); |
| } |
| #else |
| static void register_sched_domain_sysctl(void) |
| { |
| } |
| static void unregister_sched_domain_sysctl(void) |
| { |
| } |
| #endif |
| |
| static void set_rq_online(struct rq *rq) |
| { |
| if (!rq->online) { |
| const struct sched_class *class; |
| |
| cpu_set(rq->cpu, rq->rd->online); |
| rq->online = 1; |
| |
| for_each_class(class) { |
| if (class->rq_online) |
| class->rq_online(rq); |
| } |
| } |
| } |
| |
| static void set_rq_offline(struct rq *rq) |
| { |
| if (rq->online) { |
| const struct sched_class *class; |
| |
| for_each_class(class) { |
| if (class->rq_offline) |
| class->rq_offline(rq); |
| } |
| |
| cpu_clear(rq->cpu, rq->rd->online); |
| rq->online = 0; |
| } |
| } |
| |
| /* |
| * migration_call - callback that gets triggered when a CPU is added. |
| * Here we can start up the necessary migration thread for the new CPU. |
| */ |
| static int __cpuinit |
| migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) |
| { |
| struct task_struct *p; |
| int cpu = (long)hcpu; |
| unsigned long flags; |
| struct rq *rq; |
| |
| switch (action) { |
| |
| case CPU_UP_PREPARE: |
| case CPU_UP_PREPARE_FROZEN: |
| p = kthread_create(migration_thread, hcpu, "migration/%d", cpu); |
| if (IS_ERR(p)) |
| return NOTIFY_BAD; |
| kthread_bind(p, cpu); |
| /* Must be high prio: stop_machine expects to yield to it. */ |
| rq = task_rq_lock(p, &flags); |
| __setscheduler(rq, p, SCHED_FIFO, MAX_RT_PRIO-1); |
| task_rq_unlock(rq, &flags); |
| cpu_rq(cpu)->migration_thread = p; |
| break; |
| |
| case CPU_ONLINE: |
| case CPU_ONLINE_FROZEN: |
| /* Strictly unnecessary, as first user will wake it. */ |
| wake_up_process(cpu_rq(cpu)->migration_thread); |
| |
| /* Update our root-domain */ |
| rq = cpu_rq(cpu); |
| spin_lock_irqsave(&rq->lock, flags); |
| if (rq->rd) { |
| BUG_ON(!cpu_isset(cpu, rq->rd->span)); |
| |
| set_rq_online(rq); |
| } |
| spin_unlock_irqrestore(&rq->lock, flags); |
| break; |
| |
| #ifdef CONFIG_HOTPLUG_CPU |
| case CPU_UP_CANCELED: |
| case CPU_UP_CANCELED_FROZEN: |
| if (!cpu_rq(cpu)->migration_thread) |
| break; |
| /* Unbind it from offline cpu so it can run. Fall thru. */ |
| kthread_bind(cpu_rq(cpu)->migration_thread, |
| any_online_cpu(cpu_online_map)); |
| kthread_stop(cpu_rq(cpu)->migration_thread); |
| cpu_rq(cpu)->migration_thread = NULL; |
| break; |
| |
| case CPU_DEAD: |
| case CPU_DEAD_FROZEN: |
| cpuset_lock(); /* around calls to cpuset_cpus_allowed_lock() */ |
| migrate_live_tasks(cpu); |
| rq = cpu_rq(cpu); |
| kthread_stop(rq->migration_thread); |
| rq->migration_thread = NULL; |
| /* Idle task back to normal (off runqueue, low prio) */ |
| spin_lock_irq(&rq->lock); |
| update_rq_clock(rq); |
| deactivate_task(rq, rq->idle, 0); |
| rq->idle->static_prio = MAX_PRIO; |
| __setscheduler(rq, rq->idle, SCHED_NORMAL, 0); |
| rq->idle->sched_class = &idle_sched_class; |
| migrate_dead_tasks(cpu); |
| spin_unlock_irq(&rq->lock); |
| cpuset_unlock(); |
| migrate_nr_uninterruptible(rq); |
| BUG_ON(rq->nr_running != 0); |
| |
| /* |
| * No need to migrate the tasks: it was best-effort if |
| * they didn't take sched_hotcpu_mutex. Just wake up |
| * the requestors. |
| */ |
| spin_lock_irq(&rq->lock); |
| while (!list_empty(&rq->migration_queue)) { |
| struct migration_req *req; |
| |
| req = list_entry(rq->migration_queue.next, |
| struct migration_req, list); |
| list_del_init(&req->list); |
| complete(&req->done); |
| } |
| spin_unlock_irq(&rq->lock); |
| break; |
| |
| case CPU_DYING: |
| case CPU_DYING_FROZEN: |
| /* Update our root-domain */ |
| rq = cpu_rq(cpu); |
| spin_lock_irqsave(&rq->lock, flags); |
| if (rq->rd) { |
| BUG_ON(!cpu_isset(cpu, rq->rd->span)); |
| set_rq_offline(rq); |
| } |
| spin_unlock_irqrestore(&rq->lock, flags); |
| break; |
| #endif |
| } |
| return NOTIFY_OK; |
| } |
| |
| /* Register at highest priority so that task migration (migrate_all_tasks) |
| * happens before everything else. |
| */ |
| static struct notifier_block __cpuinitdata migration_notifier = { |
| .notifier_call = migration_call, |
| .priority = 10 |
| }; |
| |
| void __init migration_init(void) |
| { |
| void *cpu = (void *)(long)smp_processor_id(); |
| int err; |
| |
| /* Start one for the boot CPU: */ |
| err = migration_call(&migration_notifier, CPU_UP_PREPARE, cpu); |
| BUG_ON(err == NOTIFY_BAD); |
| migration_call(&migration_notifier, CPU_ONLINE, cpu); |
| register_cpu_notifier(&migration_notifier); |
| } |
| #endif |
| |
| #ifdef CONFIG_SMP |
| |
| #ifdef CONFIG_SCHED_DEBUG |
| |
| static inline const char *sd_level_to_string(enum sched_domain_level lvl) |
| { |
| switch (lvl) { |
| case SD_LV_NONE: |
| return "NONE"; |
| case SD_LV_SIBLING: |
| return "SIBLING"; |
| case SD_LV_MC: |
| return "MC"; |
| case SD_LV_CPU: |
| return "CPU"; |
| case SD_LV_NODE: |
| return "NODE"; |
| case SD_LV_ALLNODES: |
| return "ALLNODES"; |
| case SD_LV_MAX: |
| return "MAX"; |
| |
| } |
| return "MAX"; |
| } |
| |
| static int sched_domain_debug_one(struct sched_domain *sd, int cpu, int level, |
| cpumask_t *groupmask) |
| { |
| struct sched_group *group = sd->groups; |
| char str[256]; |
| |
| cpulist_scnprintf(str, sizeof(str), sd->span); |
| cpus_clear(*groupmask); |
| |
| printk(KERN_DEBUG "%*s domain %d: ", level, "", level); |
| |
| if (!(sd->flags & SD_LOAD_BALANCE)) { |
| printk("does not load-balance\n"); |
| if (sd->parent) |
| printk(KERN_ERR "ERROR: !SD_LOAD_BALANCE domain" |
| " has parent"); |
| return -1; |
| } |
| |
| printk(KERN_CONT "span %s level %s\n", |
| str, sd_level_to_string(sd->level)); |
| |
| if (!cpu_isset(cpu, sd->span)) { |
| printk(KERN_ERR "ERROR: domain->span does not contain " |
| "CPU%d\n", cpu); |
| } |
| if (!cpu_isset(cpu, group->cpumask)) { |
| printk(KERN_ERR "ERROR: domain->groups does not contain" |
| " CPU%d\n", cpu); |
| } |
| |
| printk(KERN_DEBUG "%*s groups:", level + 1, ""); |
| do { |
| if (!group) { |
| printk("\n"); |
| printk(KERN_ERR "ERROR: group is NULL\n"); |
| break; |
| } |
| |
| if (!group->__cpu_power) { |
| printk(KERN_CONT "\n"); |
| printk(KERN_ERR "ERROR: domain->cpu_power not " |
| "set\n"); |
| break; |
| } |
| |
| if (!cpus_weight(group->cpumask)) { |
| printk(KERN_CONT "\n"); |
| printk(KERN_ERR "ERROR: empty group\n"); |
| break; |
| } |
| |
| if (cpus_intersects(*groupmask, group->cpumask)) { |
| printk(KERN_CONT "\n"); |
| printk(KERN_ERR "ERROR: repeated CPUs\n"); |
| break; |
| } |
| |
| cpus_or(*groupmask, *groupmask, group->cpumask); |
| |
| cpulist_scnprintf(str, sizeof(str), group->cpumask); |
| printk(KERN_CONT " %s", str); |
| |
| group = group->next; |
| } while (group != sd->groups); |
| printk(KERN_CONT "\n"); |
| |
| if (!cpus_equal(sd->span, *groupmask)) |
| printk(KERN_ERR "ERROR: groups don't span domain->span\n"); |
| |
| if (sd->parent && !cpus_subset(*groupmask, sd->parent->span)) |
| printk(KERN_ERR "ERROR: parent span is not a superset " |
| "of domain->span\n"); |
| return 0; |
| } |
| |
| static void sched_domain_debug(struct sched_domain *sd, int cpu) |
| { |
| cpumask_t *groupmask; |
| int level = 0; |
| |
| if (!sd) { |
| printk(KERN_DEBUG "CPU%d attaching NULL sched-domain.\n", cpu); |
| return; |
| } |
| |
| printk(KERN_DEBUG "CPU%d attaching sched-domain:\n", cpu); |
| |
| groupmask = kmalloc(sizeof(cpumask_t), GFP_KERNEL); |
| if (!groupmask) { |
| printk(KERN_DEBUG "Cannot load-balance (out of memory)\n"); |
| return; |
| } |
| |
| for (;;) { |
| if (sched_domain_debug_one(sd, cpu, level, groupmask)) |
| break; |
| level++; |
| sd = sd->parent; |
| if (!sd) |
| break; |
| } |
| kfree(groupmask); |
| } |
| #else /* !CONFIG_SCHED_DEBUG */ |
| # define sched_domain_debug(sd, cpu) do { } while (0) |
| #endif /* CONFIG_SCHED_DEBUG */ |
| |
| static int sd_degenerate(struct sched_domain *sd) |
| { |
| if (cpus_weight(sd->span) == 1) |
| return 1; |
| |
| /* Following flags need at least 2 groups */ |
| if (sd->flags & (SD_LOAD_BALANCE | |
| SD_BALANCE_NEWIDLE | |
| SD_BALANCE_FORK | |
| SD_BALANCE_EXEC | |
| SD_SHARE_CPUPOWER | |
| SD_SHARE_PKG_RESOURCES)) { |
| if (sd->groups != sd->groups->next) |
| return 0; |
| } |
| |
| /* Following flags don't use groups */ |
| if (sd->flags & (SD_WAKE_IDLE | |
| SD_WAKE_AFFINE | |
| SD_WAKE_BALANCE)) |
| return 0; |
| |
| return 1; |
| } |
| |
| static int |
| sd_parent_degenerate(struct sched_domain *sd, struct sched_domain *parent) |
| { |
| unsigned long cflags = sd->flags, pflags = parent->flags; |
| |
| if (sd_degenerate(parent)) |
| return 1; |
| |
| if (!cpus_equal(sd->span, parent->span)) |
| return 0; |
| |
| /* Does parent contain flags not in child? */ |
| /* WAKE_BALANCE is a subset of WAKE_AFFINE */ |
| if (cflags & SD_WAKE_AFFINE) |
| pflags &= ~SD_WAKE_BALANCE; |
| /* Flags needing groups don't count if only 1 group in parent */ |
| if (parent->groups == parent->groups->next) { |
| pflags &= ~(SD_LOAD_BALANCE | |
| SD_BALANCE_NEWIDLE | |
| SD_BALANCE_FORK | |
| SD_BALANCE_EXEC | |
| SD_SHARE_CPUPOWER | |
| SD_SHARE_PKG_RESOURCES); |
| } |
| if (~cflags & pflags) |
| return 0; |
| |
| return 1; |
| } |
| |
| static void rq_attach_root(struct rq *rq, struct root_domain *rd) |
| { |
| unsigned long flags; |
| |
| spin_lock_irqsave(&rq->lock, flags); |
| |
| if (rq->rd) { |
| struct root_domain *old_rd = rq->rd; |
| |
| if (cpu_isset(rq->cpu, old_rd->online)) |
| set_rq_offline(rq); |
| |
| cpu_clear(rq->cpu, old_rd->span); |
| |
| if (atomic_dec_and_test(&old_rd->refcount)) |
| kfree(old_rd); |
| } |
| |
| atomic_inc(&rd->refcount); |
| rq->rd = rd; |
| |
| cpu_set(rq->cpu, rd->span); |
| if (cpu_isset(rq->cpu, cpu_online_map)) |
| set_rq_online(rq); |
| |
| spin_unlock_irqrestore(&rq->lock, flags); |
| } |
| |
| static void init_rootdomain(struct root_domain *rd) |
| { |
| memset(rd, 0, sizeof(*rd)); |
| |
| cpus_clear(rd->span); |
| cpus_clear(rd->online); |
| |
| cpupri_init(&rd->cpupri); |
| } |
| |
| static void init_defrootdomain(void) |
| { |
| init_rootdomain(&def_root_domain); |
| atomic_set(&def_root_domain.refcount, 1); |
| } |
| |
| static struct root_domain *alloc_rootdomain(void) |
| { |
| struct root_domain *rd; |
| |
| rd = kmalloc(sizeof(*rd), GFP_KERNEL); |
| if (!rd) |
| return NULL; |
| |
| init_rootdomain(rd); |
| |
| return rd; |
| } |
| |
| /* |
| * Attach the domain 'sd' to 'cpu' as its base domain. Callers must |
| * hold the hotplug lock. |
| */ |
| static void |
| cpu_attach_domain(struct sched_domain *sd, struct root_domain *rd, int cpu) |
| { |
| struct rq *rq = cpu_rq(cpu); |
| struct sched_domain *tmp; |
| |
| /* Remove the sched domains which do not contribute to scheduling. */ |
| for (tmp = sd; tmp; tmp = tmp->parent) { |
| struct sched_domain *parent = tmp->parent; |
| if (!parent) |
| break; |
| if (sd_parent_degenerate(tmp, parent)) { |
| tmp->parent = parent->parent; |
| if (parent->parent) |
| parent->parent->child = tmp; |
| } |
| } |
| |
| if (sd && sd_degenerate(sd)) { |
| sd = sd->parent; |
| if (sd) |
| sd->child = NULL; |
| } |
| |
| sched_domain_debug(sd, cpu); |
| |
| rq_attach_root(rq, rd); |
| rcu_assign_pointer(rq->sd, sd); |
| } |
| |
| /* cpus with isolated domains */ |
| static cpumask_t cpu_isolated_map = CPU_MASK_NONE; |
| |
| /* Setup the mask of cpus configured for isolated domains */ |
| static int __init isolated_cpu_setup(char *str) |
| { |
| int ints[NR_CPUS], i; |
| |
| str = get_options(str, ARRAY_SIZE(ints), ints); |
| cpus_clear(cpu_isolated_map); |
| for (i = 1; i <= ints[0]; i++) |
| if (ints[i] < NR_CPUS) |
| cpu_set(ints[i], cpu_isolated_map); |
| return 1; |
| } |
| |
| __setup("isolcpus=", isolated_cpu_setup); |
| |
| /* |
| * init_sched_build_groups takes the cpumask we wish to span, and a pointer |
| * to a function which identifies what group(along with sched group) a CPU |
| * belongs to. The return value of group_fn must be a >= 0 and < NR_CPUS |
| * (due to the fact that we keep track of groups covered with a cpumask_t). |
| * |
| * init_sched_build_groups will build a circular linked list of the groups |
| * covered by the given span, and will set each group's ->cpumask correctly, |
| * and ->cpu_power to 0. |
| */ |
| static void |
| init_sched_build_groups(const cpumask_t *span, const cpumask_t *cpu_map, |
| int (*group_fn)(int cpu, const cpumask_t *cpu_map, |
| struct sched_group **sg, |
| cpumask_t *tmpmask), |
| cpumask_t *covered, cpumask_t *tmpmask) |
| { |
| struct sched_group *first = NULL, *last = NULL; |
| int i; |
| |
| cpus_clear(*covered); |
| |
| for_each_cpu_mask(i, *span) { |
| struct sched_group *sg; |
| int group = group_fn(i, cpu_map, &sg, tmpmask); |
| int j; |
| |
| if (cpu_isset(i, *covered)) |
| continue; |
| |
| cpus_clear(sg->cpumask); |
| sg->__cpu_power = 0; |
| |
| for_each_cpu_mask(j, *span) { |
| if (group_fn(j, cpu_map, NULL, tmpmask) != group) |
| continue; |
| |
| cpu_set(j, *covered); |
| cpu_set(j, sg->cpumask); |
| } |
| if (!first) |
| first = sg; |
| if (last) |
| last->next = sg; |
| last = sg; |
| } |
| last->next = first; |
| } |
| |
| #define SD_NODES_PER_DOMAIN 16 |
| |
| #ifdef CONFIG_NUMA |
| |
| /** |
| * find_next_best_node - find the next node to include in a sched_domain |
| * @node: node whose sched_domain we're building |
| * @used_nodes: nodes already in the sched_domain |
| * |
| * Find the next node to include in a given scheduling domain. Simply |
| * finds the closest node not already in the @used_nodes map. |
| * |
| * Should use nodemask_t. |
| */ |
| static int find_next_best_node(int node, nodemask_t *used_nodes) |
| { |
| int i, n, val, min_val, best_node = 0; |
| |
| min_val = INT_MAX; |
| |
| for (i = 0; i < nr_node_ids; i++) { |
| /* Start at @node */ |
| n = (node + i) % nr_node_ids; |
| |
| if (!nr_cpus_node(n)) |
| continue; |
| |
| /* Skip already used nodes */ |
| if (node_isset(n, *used_nodes)) |
| continue; |
| |
| /* Simple min distance search */ |
| val = node_distance(node, n); |
| |
| if (val < min_val) { |
| min_val = val; |
| best_node = n; |
| } |
| } |
| |
| node_set(best_node, *used_nodes); |
| return best_node; |
| } |
| |
| /** |
| * sched_domain_node_span - get a cpumask for a node's sched_domain |
| * @node: node whose cpumask we're constructing |
| * @span: resulting cpumask |
| * |
| * Given a node, construct a good cpumask for its sched_domain to span. It |
| * should be one that prevents unnecessary balancing, but also spreads tasks |
| * out optimally. |
| */ |
| static void sched_domain_node_span(int node, cpumask_t *span) |
| { |
| nodemask_t used_nodes; |
| node_to_cpumask_ptr(nodemask, node); |
| int i; |
| |
| cpus_clear(*span); |
| nodes_clear(used_nodes); |
| |
| cpus_or(*span, *span, *nodemask); |
| node_set(node, used_nodes); |
| |
| for (i = 1; i < SD_NODES_PER_DOMAIN; i++) { |
| int next_node = find_next_best_node(node, &used_nodes); |
| |
| node_to_cpumask_ptr_next(nodemask, next_node); |
| cpus_or(*span, *span, *nodemask); |
| } |
| } |
| #endif /* CONFIG_NUMA */ |
| |
| int sched_smt_power_savings = 0, sched_mc_power_savings = 0; |
| |
| /* |
| * SMT sched-domains: |
| */ |
| #ifdef CONFIG_SCHED_SMT |
| static DEFINE_PER_CPU(struct sched_domain, cpu_domains); |
| static DEFINE_PER_CPU(struct sched_group, sched_group_cpus); |
| |
| static int |
| cpu_to_cpu_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg, |
| cpumask_t *unused) |
| { |
| if (sg) |
| *sg = &per_cpu(sched_group_cpus, cpu); |
| return cpu; |
| } |
| #endif /* CONFIG_SCHED_SMT */ |
| |
| /* |
| * multi-core sched-domains: |
| */ |
| #ifdef CONFIG_SCHED_MC |
| static DEFINE_PER_CPU(struct sched_domain, core_domains); |
| static DEFINE_PER_CPU(struct sched_group, sched_group_core); |
| #endif /* CONFIG_SCHED_MC */ |
| |
| #if defined(CONFIG_SCHED_MC) && defined(CONFIG_SCHED_SMT) |
| static int |
| cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg, |
| cpumask_t *mask) |
| { |
| int group; |
| |
| *mask = per_cpu(cpu_sibling_map, cpu); |
| cpus_and(*mask, *mask, *cpu_map); |
| group = first_cpu(*mask); |
| if (sg) |
| *sg = &per_cpu(sched_group_core, group); |
| return group; |
| } |
| #elif defined(CONFIG_SCHED_MC) |
| static int |
| cpu_to_core_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg, |
| cpumask_t *unused) |
| { |
| if (sg) |
| *sg = &per_cpu(sched_group_core, cpu); |
| return cpu; |
| } |
| #endif |
| |
| static DEFINE_PER_CPU(struct sched_domain, phys_domains); |
| static DEFINE_PER_CPU(struct sched_group, sched_group_phys); |
| |
| static int |
| cpu_to_phys_group(int cpu, const cpumask_t *cpu_map, struct sched_group **sg, |
| cpumask_t *mask) |
| { |
| int group; |
| #ifdef CONFIG_SCHED_MC |
| *mask = cpu_coregroup_map(cpu); |
| cpus_and(*mask, *mask, *cpu_map); |
| group = first_cpu(*mask); |
| #elif defined(CONFIG_SCHED_SMT) |
| *mask = per_cpu(cpu_sibling_map, cpu); |
| cpus_and(*mask, *mask, *cpu_map); |
| group = first_cpu(*mask); |
| #else |
| group = cpu; |
| #endif |
| if (sg) |
| *sg = &per_cpu(sched_group_phys, group); |
| return group; |
| } |
| |
| #ifdef CONFIG_NUMA |
| /* |
| * The init_sched_build_groups can't handle what we want to do with node |
| * groups, so roll our own. Now each node has its own list of groups which |
| * gets dynamically allocated. |
| */ |
| static DEFINE_PER_CPU(struct sched_domain, node_domains); |
| static struct sched_group ***sched_group_nodes_bycpu; |
| |
| static DEFINE_PER_CPU(struct sched_domain, allnodes_domains); |
| static DEFINE_PER_CPU(struct sched_group, sched_group_allnodes); |
| |
| static int cpu_to_allnodes_group(int cpu, const cpumask_t *cpu_map, |
| struct sched_group **sg, cpumask_t *nodemask) |
| { |
| int group; |
| |
| *nodemask = node_to_cpumask(cpu_to_node(cpu)); |
| cpus_and(*nodemask, *nodemask, *cpu_map); |
| group = first_cpu(*nodemask); |
| |
| if (sg) |
| *sg = &per_cpu(sched_group_allnodes, group); |
| return group; |
| } |
| |
| static void init_numa_sched_groups_power(struct sched_group *group_head) |
| { |
| struct sched_group *sg = group_head; |
| int j; |
| |
| if (!sg) |
| return; |
| do { |
| for_each_cpu_mask(j, sg->cpumask) { |
| struct sched_domain *sd; |
| |
| sd = &per_cpu(phys_domains, j); |
| if (j != first_cpu(sd->groups->cpumask)) { |
| /* |
| * Only add "power" once for each |
| * physical package. |
| */ |
| continue; |
| } |
| |
| sg_inc_cpu_power(sg, sd->groups->__cpu_power); |
| } |
| sg = sg->next; |
| } while (sg != group_head); |
| } |
| #endif /* CONFIG_NUMA */ |
| |
| #ifdef CONFIG_NUMA |
| /* Free memory allocated for various sched_group structures */ |
| static void free_sched_groups(const cpumask_t *cpu_map, cpumask_t *nodemask) |
| { |
| int cpu, i; |
| |
| for_each_cpu_mask(cpu, *cpu_map) { |
| struct sched_group **sched_group_nodes |
| = sched_group_nodes_bycpu[cpu]; |
| |
| if (!sched_group_nodes) |
| continue; |
| |
| for (i = 0; i < nr_node_ids; i++) { |
| struct sched_group *oldsg, *sg = sched_group_nodes[i]; |
| |
| *nodemask = node_to_cpumask(i); |
| cpus_and(*nodemask, *nodemask, *cpu_map); |
| if (cpus_empty(*nodemask)) |
| continue; |
| |
| if (sg == NULL) |
| continue; |
| sg = sg->next; |
| next_sg: |
| oldsg = sg; |
| sg = sg->next; |
| kfree(oldsg); |
| if (oldsg != sched_group_nodes[i]) |
| goto next_sg; |
| } |
| kfree(sched_group_nodes); |
| sched_group_nodes_bycpu[cpu] = NULL; |
| } |
| } |
| #else /* !CONFIG_NUMA */ |
| static void free_sched_groups(const cpumask_t *cpu_map, cpumask_t *nodemask) |
| { |
| } |
| #endif /* CONFIG_NUMA */ |
| |
| /* |
| * Initialize sched groups cpu_power. |
| * |
| * cpu_power indicates the capacity of sched group, which is used while |
| * distributing the load between different sched groups in a sched domain. |
| * Typically cpu_power for all the groups in a sched domain will be same unless |
| * there are asymmetries in the topology. If there are asymmetries, group |
| * having more cpu_power will pickup more load compared to the group having |
| * less cpu_power. |
| * |
| * cpu_power will be a multiple of SCHED_LOAD_SCALE. This multiple represents |
| * the maximum number of tasks a group can handle in the presence of other idle |
| * or lightly loaded groups in the same sched domain. |
| */ |
| static void init_sched_groups_power(int cpu, struct sched_domain *sd) |
| { |
| struct sched_domain *child; |
| struct sched_group *group; |
| |
| WARN_ON(!sd || !sd->groups); |
| |
| if (cpu != first_cpu(sd->groups->cpumask)) |
| return; |
| |
| child = sd->child; |
| |
| sd->groups->__cpu_power = 0; |
| |
| /* |
| * For perf policy, if the groups in child domain share resources |
| * (for example cores sharing some portions of the cache hierarchy |
| * or SMT), then set this domain groups cpu_power such that each group |
| * can handle only one task, when there are other idle groups in the |
| * same sched domain. |
| */ |
| if (!child || (!(sd->flags & SD_POWERSAVINGS_BALANCE) && |
| (child->flags & |
| (SD_SHARE_CPUPOWER | SD_SHARE_PKG_RESOURCES)))) { |
| sg_inc_cpu_power(sd->groups, SCHED_LOAD_SCALE); |
| return; |
| } |
| |
| /* |
| * add cpu_power of each child group to this groups cpu_power |
| */ |
| group = child->groups; |
| do { |
| sg_inc_cpu_power(sd->groups, group->__cpu_power); |
| group = group->next; |
| } while (group != child->groups); |
| } |
| |
| /* |
| * Initializers for schedule domains |
| * Non-inlined to reduce accumulated stack pressure in build_sched_domains() |
| */ |
| |
| #define SD_INIT(sd, type) sd_init_##type(sd) |
| #define SD_INIT_FUNC(type) \ |
| static noinline void sd_init_##type(struct sched_domain *sd) \ |
| { \ |
| memset(sd, 0, sizeof(*sd)); \ |
| *sd = SD_##type##_INIT; \ |
| sd->level = SD_LV_##type; \ |
| } |
| |
| SD_INIT_FUNC(CPU) |
| #ifdef CONFIG_NUMA |
| SD_INIT_FUNC(ALLNODES) |
| SD_INIT_FUNC(NODE) |
| #endif |
| #ifdef CONFIG_SCHED_SMT |
| SD_INIT_FUNC(SIBLING) |
| #endif |
| #ifdef CONFIG_SCHED_MC |
| SD_INIT_FUNC(MC) |
| #endif |
| |
| /* |
| * To minimize stack usage kmalloc room for cpumasks and share the |
| * space as the usage in build_sched_domains() dictates. Used only |
| * if the amount of space is significant. |
| */ |
| struct allmasks { |
| cpumask_t tmpmask; /* make this one first */ |
| union { |
| cpumask_t nodemask; |
| cpumask_t this_sibling_map; |
| cpumask_t this_core_map; |
| }; |
| cpumask_t send_covered; |
| |
| #ifdef CONFIG_NUMA |
| cpumask_t domainspan; |
| cpumask_t covered; |
| cpumask_t notcovered; |
| #endif |
| }; |
| |
| #if NR_CPUS > 128 |
| #define SCHED_CPUMASK_ALLOC 1 |
| #define SCHED_CPUMASK_FREE(v) kfree(v) |
| #define SCHED_CPUMASK_DECLARE(v) struct allmasks *v |
| #else |
| #define SCHED_CPUMASK_ALLOC 0 |
| #define SCHED_CPUMASK_FREE(v) |
| #define SCHED_CPUMASK_DECLARE(v) struct allmasks _v, *v = &_v |
| #endif |
| |
| #define SCHED_CPUMASK_VAR(v, a) cpumask_t *v = (cpumask_t *) \ |
| ((unsigned long)(a) + offsetof(struct allmasks, v)) |
| |
| static int default_relax_domain_level = -1; |
| |
| static int __init setup_relax_domain_level(char *str) |
| { |
| unsigned long val; |
| |
| val = simple_strtoul(str, NULL, 0); |
| if (val < SD_LV_MAX) |
| default_relax_domain_level = val; |
| |
| return 1; |
| } |
| __setup("relax_domain_level=", setup_relax_domain_level); |
| |
| static void set_domain_attribute(struct sched_domain *sd, |
| struct sched_domain_attr *attr) |
| { |
| int request; |
| |
| if (!attr || attr->relax_domain_level < 0) { |
| if (default_relax_domain_level < 0) |
| return; |
| else |
| request = default_relax_domain_level; |
| } else |
| request = attr->relax_domain_level; |
| if (request < sd->level) { |
| /* turn off idle balance on this domain */ |
| sd->flags &= ~(SD_WAKE_IDLE|SD_BALANCE_NEWIDLE); |
| } else { |
| /* turn on idle balance on this domain */ |
| sd->flags |= (SD_WAKE_IDLE_FAR|SD_BALANCE_NEWIDLE); |
| } |
| } |
| |
| /* |
| * Build sched domains for a given set of cpus and attach the sched domains |
| * to the individual cpus |
| */ |
| static int __build_sched_domains(const cpumask_t *cpu_map, |
| struct sched_domain_attr *attr) |
| { |
| int i; |
| struct root_domain *rd; |
| SCHED_CPUMASK_DECLARE(allmasks); |
| cpumask_t *tmpmask; |
| #ifdef CONFIG_NUMA |
| struct sched_group **sched_group_nodes = NULL; |
| int sd_allnodes = 0; |
| |
| /* |
| * Allocate the per-node list of sched groups |
| */ |
| sched_group_nodes = kcalloc(nr_node_ids, sizeof(struct sched_group *), |
| GFP_KERNEL); |
| if (!sched_group_nodes) { |
| printk(KERN_WARNING "Can not alloc sched group node list\n"); |
| return -ENOMEM; |
| } |
| #endif |
| |
| rd = alloc_rootdomain(); |
| if (!rd) { |
| printk(KERN_WARNING "Cannot alloc root domain\n"); |
| #ifdef CONFIG_NUMA |
| kfree(sched_group_nodes); |
| #endif |
| return -ENOMEM; |
| } |
| |
| #if SCHED_CPUMASK_ALLOC |
| /* get space for all scratch cpumask variables */ |
| allmasks = kmalloc(sizeof(*allmasks), GFP_KERNEL); |
| if (!allmasks) { |
| printk(KERN_WARNING "Cannot alloc cpumask array\n"); |
| kfree(rd); |
| #ifdef CONFIG_NUMA |
| kfree(sched_group_nodes); |
| #endif |
| return -ENOMEM; |
| } |
| #endif |
| tmpmask = (cpumask_t *)allmasks; |
| |
| |
| #ifdef CONFIG_NUMA |
| sched_group_nodes_bycpu[first_cpu(*cpu_map)] = sched_group_nodes; |
| #endif |
| |
| /* |
| * Set up domains for cpus specified by the cpu_map. |
| */ |
| for_each_cpu_mask(i, *cpu_map) { |
| struct sched_domain *sd = NULL, *p; |
| SCHED_CPUMASK_VAR(nodemask, allmasks); |
| |
| *nodemask = node_to_cpumask(cpu_to_node(i)); |
| cpus_and(*nodemask, *nodemask, *cpu_map); |
| |
| #ifdef CONFIG_NUMA |
| if (cpus_weight(*cpu_map) > |
| SD_NODES_PER_DOMAIN*cpus_weight(*nodemask)) { |
| sd = &per_cpu(allnodes_domains, i); |
| SD_INIT(sd, ALLNODES); |
| set_domain_attribute(sd, attr); |
| sd->span = *cpu_map; |
| cpu_to_allnodes_group(i, cpu_map, &sd->groups, tmpmask); |
| p = sd; |
| sd_allnodes = 1; |
| } else |
| p = NULL; |
| |
| sd = &per_cpu(node_domains, i); |
| SD_INIT(sd, NODE); |
| set_domain_attribute(sd, attr); |
| sched_domain_node_span(cpu_to_node(i), &sd->span); |
| sd->parent = p; |
| if (p) |
| p->child = sd; |
| cpus_and(sd->span, sd->span, *cpu_map); |
| #endif |
| |
| p = sd; |
| sd = &per_cpu(phys_domains, i); |
| SD_INIT(sd, CPU); |
| set_domain_attribute(sd, attr); |
| sd->span = *nodemask; |
| sd->parent = p; |
| if (p) |
| p->child = sd; |
| cpu_to_phys_group(i, cpu_map, &sd->groups, tmpmask); |
| |
| #ifdef CONFIG_SCHED_MC |
| p = sd; |
| sd = &per_cpu(core_domains, i); |
| SD_INIT(sd, MC); |
| set_domain_attribute(sd, attr); |
| sd->span = cpu_coregroup_map(i); |
| cpus_and(sd->span, sd->span, *cpu_map); |
| sd->parent = p; |
| p->child = sd; |
| cpu_to_core_group(i, cpu_map, &sd->groups, tmpmask); |
| #endif |
| |
| #ifdef CONFIG_SCHED_SMT |
| p = sd; |
| sd = &per_cpu(cpu_domains, i); |
| SD_INIT(sd, SIBLING); |
| set_domain_attribute(sd, attr); |
| sd->span = per_cpu(cpu_sibling_map, i); |
| cpus_and(sd->span, sd->span, *cpu_map); |
| sd->parent = p; |
| p->child = sd; |
| cpu_to_cpu_group(i, cpu_map, &sd->groups, tmpmask); |
| #endif |
| } |
| |
| #ifdef CONFIG_SCHED_SMT |
| /* Set up CPU (sibling) groups */ |
| for_each_cpu_mask(i, *cpu_map) { |
| SCHED_CPUMASK_VAR(this_sibling_map, allmasks); |
| SCHED_CPUMASK_VAR(send_covered, allmasks); |
| |
| *this_sibling_map = per_cpu(cpu_sibling_map, i); |
| cpus_and(*this_sibling_map, *this_sibling_map, *cpu_map); |
| if (i != first_cpu(*this_sibling_map)) |
| continue; |
| |
| init_sched_build_groups(this_sibling_map, cpu_map, |
| &cpu_to_cpu_group, |
| send_covered, tmpmask); |
| } |
| #endif |
| |
| #ifdef CONFIG_SCHED_MC |
| /* Set up multi-core groups */ |
| for_each_cpu_mask(i, *cpu_map) { |
| SCHED_CPUMASK_VAR(this_core_map, allmasks); |
| SCHED_CPUMASK_VAR(send_covered, allmasks); |
| |
| *this_core_map = cpu_coregroup_map(i); |
| cpus_and(*this_core_map, *this_core_map, *cpu_map); |
| if (i != first_cpu(*this_core_map)) |
| continue; |
| |
| init_sched_build_groups(this_core_map, cpu_map, |
| &cpu_to_core_group, |
| send_covered, tmpmask); |
| } |
| #endif |
| |
| /* Set up physical groups */ |
| for (i = 0; i < nr_node_ids; i++) { |
| SCHED_CPUMASK_VAR(nodemask, allmasks); |
| SCHED_CPUMASK_VAR(send_covered, allmasks); |
| |
| *nodemask = node_to_cpumask(i); |
| cpus_and(*nodemask, *nodemask, *cpu_map); |
| if (cpus_empty(*nodemask)) |
| continue; |
| |
| init_sched_build_groups(nodemask, cpu_map, |
| &cpu_to_phys_group, |
| send_covered, tmpmask); |
| } |
| |
| #ifdef CONFIG_NUMA |
| /* Set up node groups */ |
| if (sd_allnodes) { |
| SCHED_CPUMASK_VAR(send_covered, allmasks); |
| |
| init_sched_build_groups(cpu_map, cpu_map, |
| &cpu_to_allnodes_group, |
| send_covered, tmpmask); |
| } |
| |
| for (i = 0; i < nr_node_ids; i++) { |
| /* Set up node groups */ |
| struct sched_group *sg, *prev; |
| SCHED_CPUMASK_VAR(nodemask, allmasks); |
| SCHED_CPUMASK_VAR(domainspan, allmasks); |
| SCHED_CPUMASK_VAR(covered, allmasks); |
| int j; |
| |
| *nodemask = node_to_cpumask(i); |
| cpus_clear(*covered); |
| |
| cpus_and(*nodemask, *nodemask, *cpu_map); |
| if (cpus_empty(*nodemask)) { |
| sched_group_nodes[i] = NULL; |
| continue; |
| } |
| |
| sched_domain_node_span(i, domainspan); |
| cpus_and(*domainspan, *domainspan, *cpu_map); |
| |
| sg = kmalloc_node(sizeof(struct sched_group), GFP_KERNEL, i); |
| if (!sg) { |
| printk(KERN_WARNING "Can not alloc domain group for " |
| "node %d\n", i); |
| goto error; |
| } |
| sched_group_nodes[i] = sg; |
| for_each_cpu_mask(j, *nodemask) { |
| struct sched_domain *sd; |
| |
| sd = &per_cpu(node_domains, j); |
| sd->groups = sg; |
| } |
| sg->__cpu_power = 0; |
| sg->cpumask = *nodemask; |
| sg->next = sg; |
| cpus_or(*covered, *covered, *nodemask); |
| prev = sg; |
| |
| for (j = 0; j < nr_node_ids; j++) { |
| SCHED_CPUMASK_VAR(notcovered, allmasks); |
| int n = (i + j) % nr_node_ids; |
| node_to_cpumask_ptr(pnodemask, n); |
| |
| cpus_complement(*notcovered, *covered); |
| cpus_and(*tmpmask, *notcovered, *cpu_map); |
| cpus_and(*tmpmask, *tmpmask, *domainspan); |
| if (cpus_empty(*tmpmask)) |
| break; |
| |
| cpus_and(*tmpmask, *tmpmask, *pnodemask); |
| if (cpus_empty(*tmpmask)) |
| continue; |
| |
| sg = kmalloc_node(sizeof(struct sched_group), |
| GFP_KERNEL, i); |
| if (!sg) { |
| printk(KERN_WARNING |
| "Can not alloc domain group for node %d\n", j); |
| goto error; |
| } |
| sg->__cpu_power = 0; |
| sg->cpumask = *tmpmask; |
| sg->next = prev->next; |
| cpus_or(*covered, *covered, *tmpmask); |
| prev->next = sg; |
| prev = sg; |
| } |
| } |
| #endif |
| |
| /* Calculate CPU power for physical packages and nodes */ |
| #ifdef CONFIG_SCHED_SMT |
| for_each_cpu_mask(i, *cpu_map) { |
| struct sched_domain *sd = &per_cpu(cpu_domains, i); |
| |
| init_sched_groups_power(i, sd); |
| } |
| #endif |
| #ifdef CONFIG_SCHED_MC |
| for_each_cpu_mask(i, *cpu_map) { |
| struct sched_domain *sd = &per_cpu(core_domains, i); |
| |
| init_sched_groups_power(i, sd); |
| } |
| #endif |
| |
| for_each_cpu_mask(i, *cpu_map) { |
| struct sched_domain *sd = &per_cpu(phys_domains, i); |
| |
| init_sched_groups_power(i, sd); |
| } |
| |
| #ifdef CONFIG_NUMA |
| for (i = 0; i < nr_node_ids; i++) |
| init_numa_sched_groups_power(sched_group_nodes[i]); |
| |
| if (sd_allnodes) { |
| struct sched_group *sg; |
| |
| cpu_to_allnodes_group(first_cpu(*cpu_map), cpu_map, &sg, |
| tmpmask); |
| init_numa_sched_groups_power(sg); |
| } |
| #endif |
| |
| /* Attach the domains */ |
| for_each_cpu_mask(i, *cpu_map) { |
| struct sched_domain *sd; |
| #ifdef CONFIG_SCHED_SMT |
| sd = &per_cpu(cpu_domains, i); |
| #elif defined(CONFIG_SCHED_MC) |
| sd = &per_cpu(core_domains, i); |
| #else |
| sd = &per_cpu(phys_domains, i); |
| #endif |
| cpu_attach_domain(sd, rd, i); |
| } |
| |
| SCHED_CPUMASK_FREE((void *)allmasks); |
| return 0; |
| |
| #ifdef CONFIG_NUMA |
| error: |
| free_sched_groups(cpu_map, tmpmask); |
| SCHED_CPUMASK_FREE((void *)allmasks); |
| return -ENOMEM; |
| #endif |
| } |
| |
| static int build_sched_domains(const cpumask_t *cpu_map) |
| { |
| return __build_sched_domains(cpu_map, NULL); |
| } |
| |
| static cpumask_t *doms_cur; /* current sched domains */ |
| static int ndoms_cur; /* number of sched domains in 'doms_cur' */ |
| static struct sched_domain_attr *dattr_cur; |
| /* attribues of custom domains in 'doms_cur' */ |
| |
| /* |
| * Special case: If a kmalloc of a doms_cur partition (array of |
| * cpumask_t) fails, then fallback to a single sched domain, |
| * as determined by the single cpumask_t fallback_doms. |
| */ |
| static cpumask_t fallback_doms; |
| |
| void __attribute__((weak)) arch_update_cpu_topology(void) |
| { |
| } |
| |
| /* |
| * Free current domain masks. |
| * Called after all cpus are attached to NULL domain. |
| */ |
| static void free_sched_domains(void) |
| { |
| ndoms_cur = 0; |
| if (doms_cur != &fallback_doms) |
| kfree(doms_cur); |
| doms_cur = &fallback_doms; |
| } |
| |
| /* |
| * Set up scheduler domains and groups. Callers must hold the hotplug lock. |
| * For now this just excludes isolated cpus, but could be used to |
| * exclude other special cases in the future. |
| */ |
| static int arch_init_sched_domains(const cpumask_t *cpu_map) |
| { |
| int err; |
| |
| arch_update_cpu_topology(); |
| ndoms_cur = 1; |
| doms_cur = kmalloc(sizeof(cpumask_t), GFP_KERNEL); |
| if (!doms_cur) |
| doms_cur = &fallback_doms; |
| cpus_andnot(*doms_cur, *cpu_map, cpu_isolated_map); |
| dattr_cur = NULL; |
| err = build_sched_domains(doms_cur); |
| register_sched_domain_sysctl(); |
| |
| return err; |
| } |
| |
| static void arch_destroy_sched_domains(const cpumask_t *cpu_map, |
| cpumask_t *tmpmask) |
| { |
| free_sched_groups(cpu_map, tmpmask); |
| } |
| |
| /* |
| * Detach sched domains from a group of cpus specified in cpu_map |
| * These cpus will now be attached to the NULL domain |
| */ |
| static void detach_destroy_domains(const cpumask_t *cpu_map) |
| { |
| cpumask_t tmpmask; |
| int i; |
| |
| unregister_sched_domain_sysctl(); |
| |
| for_each_cpu_mask(i, *cpu_map) |
| cpu_attach_domain(NULL, &def_root_domain, i); |
| synchronize_sched(); |
| arch_destroy_sched_domains(cpu_map, &tmpmask); |
| } |
| |
| /* handle null as "default" */ |
| static int dattrs_equal(struct sched_domain_attr *cur, int idx_cur, |
| struct sched_domain_attr *new, int idx_new) |
| { |
| struct sched_domain_attr tmp; |
| |
| /* fast path */ |
| if (!new && !cur) |
| return 1; |
| |
| tmp = SD_ATTR_INIT; |
| return !memcmp(cur ? (cur + idx_cur) : &tmp, |
| new ? (new + idx_new) : &tmp, |
| sizeof(struct sched_domain_attr)); |
| } |
| |
| /* |
| * Partition sched domains as specified by the 'ndoms_new' |
| * cpumasks in the array doms_new[] of cpumasks. This compares |
| * doms_new[] to the current sched domain partitioning, doms_cur[]. |
| * It destroys each deleted domain and builds each new domain. |
| * |
| * 'doms_new' is an array of cpumask_t's of length 'ndoms_new'. |
| * The masks don't intersect (don't overlap.) We should setup one |
| * sched domain for each mask. CPUs not in any of the cpumasks will |
| * not be load balanced. If the same cpumask appears both in the |
| * current 'doms_cur' domains and in the new 'doms_new', we can leave |
| * it as it is. |
| * |
| * The passed in 'doms_new' should be kmalloc'd. This routine takes |
| * ownership of it and will kfree it when done with it. If the caller |
| * failed the kmalloc call, then it can pass in doms_new == NULL, |
| * and partition_sched_domains() will fallback to the single partition |
| * 'fallback_doms'. |
| * |
| * Call with hotplug lock held |
| */ |
| void partition_sched_domains(int ndoms_new, cpumask_t *doms_new, |
| struct sched_domain_attr *dattr_new) |
| { |
| int i, j; |
| |
| mutex_lock(&sched_domains_mutex); |
| |
| /* always unregister in case we don't destroy any domains */ |
| unregister_sched_domain_sysctl(); |
| |
| if (doms_new == NULL) { |
| ndoms_new = 1; |
| doms_new = &fallback_doms; |
| cpus_andnot(doms_new[0], cpu_online_map, cpu_isolated_map); |
| dattr_new = NULL; |
| } |
| |
| /* Destroy deleted domains */ |
| for (i = 0; i < ndoms_cur; i++) { |
| for (j = 0; j < ndoms_new; j++) { |
| if (cpus_equal(doms_cur[i], doms_new[j]) |
| && dattrs_equal(dattr_cur, i, dattr_new, j)) |
| goto match1; |
| } |
| /* no match - a current sched domain not in new doms_new[] */ |
| detach_destroy_domains(doms_cur + i); |
| match1: |
| ; |
| } |
| |
| /* Build new domains */ |
| for (i = 0; i < ndoms_new; i++) { |
| for (j = 0; j < ndoms_cur; j++) { |
| if (cpus_equal(doms_new[i], doms_cur[j]) |
| && dattrs_equal(dattr_new, i, dattr_cur, j)) |
| goto match2; |
| } |
| /* no match - add a new doms_new */ |
| __build_sched_domains(doms_new + i, |
| dattr_new ? dattr_new + i : NULL); |
| match2: |
| ; |
| } |
| |
| /* Remember the new sched domains */ |
| if (doms_cur != &fallback_doms) |
| kfree(doms_cur); |
| kfree(dattr_cur); /* kfree(NULL) is safe */ |
| doms_cur = doms_new; |
| dattr_cur = dattr_new; |
| ndoms_cur = ndoms_new; |
| |
| register_sched_domain_sysctl(); |
| |
| mutex_unlock(&sched_domains_mutex); |
| } |
| |
| #if defined(CONFIG_SCHED_MC) || defined(CONFIG_SCHED_SMT) |
| int arch_reinit_sched_domains(void) |
| { |
| int err; |
| |
| get_online_cpus(); |
| mutex_lock(&sched_domains_mutex); |
| detach_destroy_domains(&cpu_online_map); |
| free_sched_domains(); |
| err = arch_init_sched_domains(&cpu_online_map); |
| mutex_unlock(&sched_domains_mutex); |
| put_online_cpus(); |
| |
| return err; |
| } |
| |
| static ssize_t sched_power_savings_store(const char *buf, size_t count, int smt) |
| { |
| int ret; |
| |
| if (buf[0] != '0' && buf[0] != '1') |
| return -EINVAL; |
| |
| if (smt) |
| sched_smt_power_savings = (buf[0] == '1'); |
| else |
| sched_mc_power_savings = (buf[0] == '1'); |
| |
| ret = arch_reinit_sched_domains(); |
| |
| return ret ? ret : count; |
| } |
| |
| #ifdef CONFIG_SCHED_MC |
| static ssize_t sched_mc_power_savings_show(struct sys_device *dev, char *page) |
| { |
| return sprintf(page, "%u\n", sched_mc_power_savings); |
| } |
| static ssize_t sched_mc_power_savings_store(struct sys_device *dev, |
| const char *buf, size_t count) |
| { |
| return sched_power_savings_store(buf, count, 0); |
| } |
| static SYSDEV_ATTR(sched_mc_power_savings, 0644, sched_mc_power_savings_show, |
| sched_mc_power_savings_store); |
| #endif |
| |
| #ifdef CONFIG_SCHED_SMT |
| static ssize_t sched_smt_power_savings_show(struct sys_device *dev, char *page) |
| { |
| return sprintf(page, "%u\n", sched_smt_power_savings); |
| } |
| static ssize_t sched_smt_power_savings_store(struct sys_device *dev, |
| const char *buf, size_t count) |
| { |
| return sched_power_savings_store(buf, count, 1); |
| } |
| static SYSDEV_ATTR(sched_smt_power_savings, 0644, sched_smt_power_savings_show, |
| sched_smt_power_savings_store); |
| #endif |
| |
| int sched_create_sysfs_power_savings_entries(struct sysdev_class *cls) |
| { |
| int err = 0; |
| |
| #ifdef CONFIG_SCHED_SMT |
| if (smt_capable()) |
| err = sysfs_create_file(&cls->kset.kobj, |
| &attr_sched_smt_power_savings.attr); |
| #endif |
| #ifdef CONFIG_SCHED_MC |
| if (!err && mc_capable()) |
| err = sysfs_create_file(&cls->kset.kobj, |
| &attr_sched_mc_power_savings.attr); |
| #endif |
| return err; |
| } |
| #endif /* CONFIG_SCHED_MC || CONFIG_SCHED_SMT */ |
| |
| /* |
| * Force a reinitialization of the sched domains hierarchy. The domains |
| * and groups cannot be updated in place without racing with the balancing |
| * code, so we temporarily attach all running cpus to the NULL domain |
| * which will prevent rebalancing while the sched domains are recalculated. |
| */ |
| static int update_sched_domains(struct notifier_block *nfb, |
| unsigned long action, void *hcpu) |
| { |
| int cpu = (int)(long)hcpu; |
| |
| switch (action) { |
| case CPU_DOWN_PREPARE: |
| case CPU_DOWN_PREPARE_FROZEN: |
| disable_runtime(cpu_rq(cpu)); |
| /* fall-through */ |
| case CPU_UP_PREPARE: |
| case CPU_UP_PREPARE_FROZEN: |
| detach_destroy_domains(&cpu_online_map); |
| free_sched_domains(); |
| return NOTIFY_OK; |
| |
| |
| case CPU_DOWN_FAILED: |
| case CPU_DOWN_FAILED_FROZEN: |
| case CPU_ONLINE: |
| case CPU_ONLINE_FROZEN: |
| enable_runtime(cpu_rq(cpu)); |
| /* fall-through */ |
| case CPU_UP_CANCELED: |
| case CPU_UP_CANCELED_FROZEN: |
| case CPU_DEAD: |
| case CPU_DEAD_FROZEN: |
| /* |
| * Fall through and re-initialise the domains. |
| */ |
| break; |
| default: |
| return NOTIFY_DONE; |
| } |
| |
| #ifndef CONFIG_CPUSETS |
| /* |
| * Create default domain partitioning if cpusets are disabled. |
| * Otherwise we let cpusets rebuild the domains based on the |
| * current setup. |
| */ |
| |
| /* The hotplug lock is already held by cpu_up/cpu_down */ |
| arch_init_sched_domains(&cpu_online_map); |
| #endif |
| |
| return NOTIFY_OK; |
| } |
| |
| void __init sched_init_smp(void) |
| { |
| cpumask_t non_isolated_cpus; |
| |
| #if defined(CONFIG_NUMA) |
| sched_group_nodes_bycpu = kzalloc(nr_cpu_ids * sizeof(void **), |
| GFP_KERNEL); |
| BUG_ON(sched_group_nodes_bycpu == NULL); |
| #endif |
| get_online_cpus(); |
| mutex_lock(&sched_domains_mutex); |
| arch_init_sched_domains(&cpu_online_map); |
| cpus_andnot(non_isolated_cpus, cpu_possible_map, cpu_isolated_map); |
| if (cpus_empty(non_isolated_cpus)) |
| cpu_set(smp_processor_id(), non_isolated_cpus); |
| mutex_unlock(&sched_domains_mutex); |
| put_online_cpus(); |
| /* XXX: Theoretical race here - CPU may be hotplugged now */ |
| hotcpu_notifier(update_sched_domains, 0); |
| init_hrtick(); |
| |
| /* Move init over to a non-isolated CPU */ |
| if (set_cpus_allowed_ptr(current, &non_isolated_cpus) < 0) |
| BUG(); |
| sched_init_granularity(); |
| } |
| #else |
| void __init sched_init_smp(void) |
| { |
| sched_init_granularity(); |
| } |
| #endif /* CONFIG_SMP */ |
| |
| int in_sched_functions(unsigned long addr) |
| { |
| return in_lock_functions(addr) || |
| (addr >= (unsigned long)__sched_text_start |
| && addr < (unsigned long)__sched_text_end); |
| } |
| |
| static void init_cfs_rq(struct cfs_rq *cfs_rq, struct rq *rq) |
| { |
| cfs_rq->tasks_timeline = RB_ROOT; |
| INIT_LIST_HEAD(&cfs_rq->tasks); |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| cfs_rq->rq = rq; |
| #endif |
| cfs_rq->min_vruntime = (u64)(-(1LL << 20)); |
| } |
| |
| static void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq) |
| { |
| struct rt_prio_array *array; |
| int i; |
| |
| array = &rt_rq->active; |
| for (i = 0; i < MAX_RT_PRIO; i++) { |
| INIT_LIST_HEAD(array->queue + i); |
| __clear_bit(i, array->bitmap); |
| } |
| /* delimiter for bitsearch: */ |
| __set_bit(MAX_RT_PRIO, array->bitmap); |
| |
| #if defined CONFIG_SMP || defined CONFIG_RT_GROUP_SCHED |
| rt_rq->highest_prio = MAX_RT_PRIO; |
| #endif |
| #ifdef CONFIG_SMP |
| rt_rq->rt_nr_migratory = 0; |
| rt_rq->overloaded = 0; |
| #endif |
| |
| rt_rq->rt_time = 0; |
| rt_rq->rt_throttled = 0; |
| rt_rq->rt_runtime = 0; |
| spin_lock_init(&rt_rq->rt_runtime_lock); |
| |
| #ifdef CONFIG_RT_GROUP_SCHED |
| rt_rq->rt_nr_boosted = 0; |
| rt_rq->rq = rq; |
| #endif |
| } |
| |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| static void init_tg_cfs_entry(struct task_group *tg, struct cfs_rq *cfs_rq, |
| struct sched_entity *se, int cpu, int add, |
| struct sched_entity *parent) |
| { |
| struct rq *rq = cpu_rq(cpu); |
| tg->cfs_rq[cpu] = cfs_rq; |
| init_cfs_rq(cfs_rq, rq); |
| cfs_rq->tg = tg; |
| if (add) |
| list_add(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list); |
| |
| tg->se[cpu] = se; |
| /* se could be NULL for init_task_group */ |
| if (!se) |
| return; |
| |
| if (!parent) |
| se->cfs_rq = &rq->cfs; |
| else |
| se->cfs_rq = parent->my_q; |
| |
| se->my_q = cfs_rq; |
| se->load.weight = tg->shares; |
| se->load.inv_weight = 0; |
| se->parent = parent; |
| } |
| #endif |
| |
| #ifdef CONFIG_RT_GROUP_SCHED |
| static void init_tg_rt_entry(struct task_group *tg, struct rt_rq *rt_rq, |
| struct sched_rt_entity *rt_se, int cpu, int add, |
| struct sched_rt_entity *parent) |
| { |
| struct rq *rq = cpu_rq(cpu); |
| |
| tg->rt_rq[cpu] = rt_rq; |
| init_rt_rq(rt_rq, rq); |
| rt_rq->tg = tg; |
| rt_rq->rt_se = rt_se; |
| rt_rq->rt_runtime = tg->rt_bandwidth.rt_runtime; |
| if (add) |
| list_add(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list); |
| |
| tg->rt_se[cpu] = rt_se; |
| if (!rt_se) |
| return; |
| |
| if (!parent) |
| rt_se->rt_rq = &rq->rt; |
| else |
| rt_se->rt_rq = parent->my_q; |
| |
| rt_se->my_q = rt_rq; |
| rt_se->parent = parent; |
| INIT_LIST_HEAD(&rt_se->run_list); |
| } |
| #endif |
| |
| void __init sched_init(void) |
| { |
| int i, j; |
| unsigned long alloc_size = 0, ptr; |
| |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| alloc_size += 2 * nr_cpu_ids * sizeof(void **); |
| #endif |
| #ifdef CONFIG_RT_GROUP_SCHED |
| alloc_size += 2 * nr_cpu_ids * sizeof(void **); |
| #endif |
| #ifdef CONFIG_USER_SCHED |
| alloc_size *= 2; |
| #endif |
| /* |
| * As sched_init() is called before page_alloc is setup, |
| * we use alloc_bootmem(). |
| */ |
| if (alloc_size) { |
| ptr = (unsigned long)alloc_bootmem(alloc_size); |
| |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| init_task_group.se = (struct sched_entity **)ptr; |
| ptr += nr_cpu_ids * sizeof(void **); |
| |
| init_task_group.cfs_rq = (struct cfs_rq **)ptr; |
| ptr += nr_cpu_ids * sizeof(void **); |
| |
| #ifdef CONFIG_USER_SCHED |
| root_task_group.se = (struct sched_entity **)ptr; |
| ptr += nr_cpu_ids * sizeof(void **); |
| |
| root_task_group.cfs_rq = (struct cfs_rq **)ptr; |
| ptr += nr_cpu_ids * sizeof(void **); |
| #endif /* CONFIG_USER_SCHED */ |
| #endif /* CONFIG_FAIR_GROUP_SCHED */ |
| #ifdef CONFIG_RT_GROUP_SCHED |
| init_task_group.rt_se = (struct sched_rt_entity **)ptr; |
| ptr += nr_cpu_ids * sizeof(void **); |
| |
| init_task_group.rt_rq = (struct rt_rq **)ptr; |
| ptr += nr_cpu_ids * sizeof(void **); |
| |
| #ifdef CONFIG_USER_SCHED |
| root_task_group.rt_se = (struct sched_rt_entity **)ptr; |
| ptr += nr_cpu_ids * sizeof(void **); |
| |
| root_task_group.rt_rq = (struct rt_rq **)ptr; |
| ptr += nr_cpu_ids * sizeof(void **); |
| #endif /* CONFIG_USER_SCHED */ |
| #endif /* CONFIG_RT_GROUP_SCHED */ |
| } |
| |
| #ifdef CONFIG_SMP |
| init_defrootdomain(); |
| #endif |
| |
| init_rt_bandwidth(&def_rt_bandwidth, |
| global_rt_period(), global_rt_runtime()); |
| |
| #ifdef CONFIG_RT_GROUP_SCHED |
| init_rt_bandwidth(&init_task_group.rt_bandwidth, |
| global_rt_period(), global_rt_runtime()); |
| #ifdef CONFIG_USER_SCHED |
| init_rt_bandwidth(&root_task_group.rt_bandwidth, |
| global_rt_period(), RUNTIME_INF); |
| #endif /* CONFIG_USER_SCHED */ |
| #endif /* CONFIG_RT_GROUP_SCHED */ |
| |
| #ifdef CONFIG_GROUP_SCHED |
| list_add(&init_task_group.list, &task_groups); |
| INIT_LIST_HEAD(&init_task_group.children); |
| |
| #ifdef CONFIG_USER_SCHED |
| INIT_LIST_HEAD(&root_task_group.children); |
| init_task_group.parent = &root_task_group; |
| list_add(&init_task_group.siblings, &root_task_group.children); |
| #endif /* CONFIG_USER_SCHED */ |
| #endif /* CONFIG_GROUP_SCHED */ |
| |
| for_each_possible_cpu(i) { |
| struct rq *rq; |
| |
| rq = cpu_rq(i); |
| spin_lock_init(&rq->lock); |
| lockdep_set_class(&rq->lock, &rq->rq_lock_key); |
| rq->nr_running = 0; |
| init_cfs_rq(&rq->cfs, rq); |
| init_rt_rq(&rq->rt, rq); |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| init_task_group.shares = init_task_group_load; |
| INIT_LIST_HEAD(&rq->leaf_cfs_rq_list); |
| #ifdef CONFIG_CGROUP_SCHED |
| /* |
| * How much cpu bandwidth does init_task_group get? |
| * |
| * In case of task-groups formed thr' the cgroup filesystem, it |
| * gets 100% of the cpu resources in the system. This overall |
| * system cpu resource is divided among the tasks of |
| * init_task_group and its child task-groups in a fair manner, |
| * based on each entity's (task or task-group's) weight |
| * (se->load.weight). |
| * |
| * In other words, if init_task_group has 10 tasks of weight |
| * 1024) and two child groups A0 and A1 (of weight 1024 each), |
| * then A0's share of the cpu resource is: |
| * |
| * A0's bandwidth = 1024 / (10*1024 + 1024 + 1024) = 8.33% |
| * |
| * We achieve this by letting init_task_group's tasks sit |
| * directly in rq->cfs (i.e init_task_group->se[] = NULL). |
| */ |
| init_tg_cfs_entry(&init_task_group, &rq->cfs, NULL, i, 1, NULL); |
| #elif defined CONFIG_USER_SCHED |
| root_task_group.shares = NICE_0_LOAD; |
| init_tg_cfs_entry(&root_task_group, &rq->cfs, NULL, i, 0, NULL); |
| /* |
| * In case of task-groups formed thr' the user id of tasks, |
| * init_task_group represents tasks belonging to root user. |
| * Hence it forms a sibling of all subsequent groups formed. |
| * In this case, init_task_group gets only a fraction of overall |
| * system cpu resource, based on the weight assigned to root |
| * user's cpu share (INIT_TASK_GROUP_LOAD). This is accomplished |
| * by letting tasks of init_task_group sit in a separate cfs_rq |
| * (init_cfs_rq) and having one entity represent this group of |
| * tasks in rq->cfs (i.e init_task_group->se[] != NULL). |
| */ |
| init_tg_cfs_entry(&init_task_group, |
| &per_cpu(init_cfs_rq, i), |
| &per_cpu(init_sched_entity, i), i, 1, |
| root_task_group.se[i]); |
| |
| #endif |
| #endif /* CONFIG_FAIR_GROUP_SCHED */ |
| |
| rq->rt.rt_runtime = def_rt_bandwidth.rt_runtime; |
| #ifdef CONFIG_RT_GROUP_SCHED |
| INIT_LIST_HEAD(&rq->leaf_rt_rq_list); |
| #ifdef CONFIG_CGROUP_SCHED |
| init_tg_rt_entry(&init_task_group, &rq->rt, NULL, i, 1, NULL); |
| #elif defined CONFIG_USER_SCHED |
| init_tg_rt_entry(&root_task_group, &rq->rt, NULL, i, 0, NULL); |
| init_tg_rt_entry(&init_task_group, |
| &per_cpu(init_rt_rq, i), |
| &per_cpu(init_sched_rt_entity, i), i, 1, |
| root_task_group.rt_se[i]); |
| #endif |
| #endif |
| |
| for (j = 0; j < CPU_LOAD_IDX_MAX; j++) |
| rq->cpu_load[j] = 0; |
| #ifdef CONFIG_SMP |
| rq->sd = NULL; |
| rq->rd = NULL; |
| rq->active_balance = 0; |
| rq->next_balance = jiffies; |
| rq->push_cpu = 0; |
| rq->cpu = i; |
| rq->online = 0; |
| rq->migration_thread = NULL; |
| INIT_LIST_HEAD(&rq->migration_queue); |
| rq_attach_root(rq, &def_root_domain); |
| #endif |
| init_rq_hrtick(rq); |
| atomic_set(&rq->nr_iowait, 0); |
| } |
| |
| set_load_weight(&init_task); |
| |
| #ifdef CONFIG_PREEMPT_NOTIFIERS |
| INIT_HLIST_HEAD(&init_task.preempt_notifiers); |
| #endif |
| |
| #ifdef CONFIG_SMP |
| open_softirq(SCHED_SOFTIRQ, run_rebalance_domains); |
| #endif |
| |
| #ifdef CONFIG_RT_MUTEXES |
| plist_head_init(&init_task.pi_waiters, &init_task.pi_lock); |
| #endif |
| |
| /* |
| * The boot idle thread does lazy MMU switching as well: |
| */ |
| atomic_inc(&init_mm.mm_count); |
| enter_lazy_tlb(&init_mm, current); |
| |
| /* |
| * Make us the idle thread. Technically, schedule() should not be |
| * called from this thread, however somewhere below it might be, |
| * but because we are the idle thread, we just pick up running again |
| * when this runqueue becomes "idle". |
| */ |
| init_idle(current, smp_processor_id()); |
| /* |
| * During early bootup we pretend to be a normal task: |
| */ |
| current->sched_class = &fair_sched_class; |
| |
| scheduler_running = 1; |
| } |
| |
| #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP |
| void __might_sleep(char *file, int line) |
| { |
| #ifdef in_atomic |
| static unsigned long prev_jiffy; /* ratelimiting */ |
| |
| if ((in_atomic() || irqs_disabled()) && |
| system_state == SYSTEM_RUNNING && !oops_in_progress) { |
| if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) |
| return; |
| prev_jiffy = jiffies; |
| printk(KERN_ERR "BUG: sleeping function called from invalid" |
| " context at %s:%d\n", file, line); |
| printk("in_atomic():%d, irqs_disabled():%d\n", |
| in_atomic(), irqs_disabled()); |
| debug_show_held_locks(current); |
| if (irqs_disabled()) |
| print_irqtrace_events(current); |
| dump_stack(); |
| } |
| #endif |
| } |
| EXPORT_SYMBOL(__might_sleep); |
| #endif |
| |
| #ifdef CONFIG_MAGIC_SYSRQ |
| static void normalize_task(struct rq *rq, struct task_struct *p) |
| { |
| int on_rq; |
| |
| update_rq_clock(rq); |
| on_rq = p->se.on_rq; |
| if (on_rq) |
| deactivate_task(rq, p, 0); |
| __setscheduler(rq, p, SCHED_NORMAL, 0); |
| if (on_rq) { |
| activate_task(rq, p, 0); |
| resched_task(rq->curr); |
| } |
| } |
| |
| void normalize_rt_tasks(void) |
| { |
| struct task_struct *g, *p; |
| unsigned long flags; |
| struct rq *rq; |
| |
| read_lock_irqsave(&tasklist_lock, flags); |
| do_each_thread(g, p) { |
| /* |
| * Only normalize user tasks: |
| */ |
| if (!p->mm) |
| continue; |
| |
| p->se.exec_start = 0; |
| #ifdef CONFIG_SCHEDSTATS |
| p->se.wait_start = 0; |
| p->se.sleep_start = 0; |
| p->se.block_start = 0; |
| #endif |
| |
| if (!rt_task(p)) { |
| /* |
| * Renice negative nice level userspace |
| * tasks back to 0: |
| */ |
| if (TASK_NICE(p) < 0 && p->mm) |
| set_user_nice(p, 0); |
| continue; |
| } |
| |
| spin_lock(&p->pi_lock); |
| rq = __task_rq_lock(p); |
| |
| normalize_task(rq, p); |
| |
| __task_rq_unlock(rq); |
| spin_unlock(&p->pi_lock); |
| } while_each_thread(g, p); |
| |
| read_unlock_irqrestore(&tasklist_lock, flags); |
| } |
| |
| #endif /* CONFIG_MAGIC_SYSRQ */ |
| |
| #ifdef CONFIG_IA64 |
| /* |
| * These functions are only useful for the IA64 MCA handling. |
| * |
| * They can only be called when the whole system has been |
| * stopped - every CPU needs to be quiescent, and no scheduling |
| * activity can take place. Using them for anything else would |
| * be a serious bug, and as a result, they aren't even visible |
| * under any other configuration. |
| */ |
| |
| /** |
| * curr_task - return the current task for a given cpu. |
| * @cpu: the processor in question. |
| * |
| * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! |
| */ |
| struct task_struct *curr_task(int cpu) |
| { |
| return cpu_curr(cpu); |
| } |
| |
| /** |
| * set_curr_task - set the current task for a given cpu. |
| * @cpu: the processor in question. |
| * @p: the task pointer to set. |
| * |
| * Description: This function must only be used when non-maskable interrupts |
| * are serviced on a separate stack. It allows the architecture to switch the |
| * notion of the current task on a cpu in a non-blocking manner. This function |
| * must be called with all CPU's synchronized, and interrupts disabled, the |
| * and caller must save the original value of the current task (see |
| * curr_task() above) and restore that value before reenabling interrupts and |
| * re-starting the system. |
| * |
| * ONLY VALID WHEN THE WHOLE SYSTEM IS STOPPED! |
| */ |
| void set_curr_task(int cpu, struct task_struct *p) |
| { |
| cpu_curr(cpu) = p; |
| } |
| |
| #endif |
| |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| static void free_fair_sched_group(struct task_group *tg) |
| { |
| int i; |
| |
| for_each_possible_cpu(i) { |
| if (tg->cfs_rq) |
| kfree(tg->cfs_rq[i]); |
| if (tg->se) |
| kfree(tg->se[i]); |
| } |
| |
| kfree(tg->cfs_rq); |
| kfree(tg->se); |
| } |
| |
| static |
| int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) |
| { |
| struct cfs_rq *cfs_rq; |
| struct sched_entity *se, *parent_se; |
| struct rq *rq; |
| int i; |
| |
| tg->cfs_rq = kzalloc(sizeof(cfs_rq) * nr_cpu_ids, GFP_KERNEL); |
| if (!tg->cfs_rq) |
| goto err; |
| tg->se = kzalloc(sizeof(se) * nr_cpu_ids, GFP_KERNEL); |
| if (!tg->se) |
| goto err; |
| |
| tg->shares = NICE_0_LOAD; |
| |
| for_each_possible_cpu(i) { |
| rq = cpu_rq(i); |
| |
| cfs_rq = kmalloc_node(sizeof(struct cfs_rq), |
| GFP_KERNEL|__GFP_ZERO, cpu_to_node(i)); |
| if (!cfs_rq) |
| goto err; |
| |
| se = kmalloc_node(sizeof(struct sched_entity), |
| GFP_KERNEL|__GFP_ZERO, cpu_to_node(i)); |
| if (!se) |
| goto err; |
| |
| parent_se = parent ? parent->se[i] : NULL; |
| init_tg_cfs_entry(tg, cfs_rq, se, i, 0, parent_se); |
| } |
| |
| return 1; |
| |
| err: |
| return 0; |
| } |
| |
| static inline void register_fair_sched_group(struct task_group *tg, int cpu) |
| { |
| list_add_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list, |
| &cpu_rq(cpu)->leaf_cfs_rq_list); |
| } |
| |
| static inline void unregister_fair_sched_group(struct task_group *tg, int cpu) |
| { |
| list_del_rcu(&tg->cfs_rq[cpu]->leaf_cfs_rq_list); |
| } |
| #else /* !CONFG_FAIR_GROUP_SCHED */ |
| static inline void free_fair_sched_group(struct task_group *tg) |
| { |
| } |
| |
| static inline |
| int alloc_fair_sched_group(struct task_group *tg, struct task_group *parent) |
| { |
| return 1; |
| } |
| |
| static inline void register_fair_sched_group(struct task_group *tg, int cpu) |
| { |
| } |
| |
| static inline void unregister_fair_sched_group(struct task_group *tg, int cpu) |
| { |
| } |
| #endif /* CONFIG_FAIR_GROUP_SCHED */ |
| |
| #ifdef CONFIG_RT_GROUP_SCHED |
| static void free_rt_sched_group(struct task_group *tg) |
| { |
| int i; |
| |
| destroy_rt_bandwidth(&tg->rt_bandwidth); |
| |
| for_each_possible_cpu(i) { |
| if (tg->rt_rq) |
| kfree(tg->rt_rq[i]); |
| if (tg->rt_se) |
| kfree(tg->rt_se[i]); |
| } |
| |
| kfree(tg->rt_rq); |
| kfree(tg->rt_se); |
| } |
| |
| static |
| int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent) |
| { |
| struct rt_rq *rt_rq; |
| struct sched_rt_entity *rt_se, *parent_se; |
| struct rq *rq; |
| int i; |
| |
| tg->rt_rq = kzalloc(sizeof(rt_rq) * nr_cpu_ids, GFP_KERNEL); |
| if (!tg->rt_rq) |
| goto err; |
| tg->rt_se = kzalloc(sizeof(rt_se) * nr_cpu_ids, GFP_KERNEL); |
| if (!tg->rt_se) |
| goto err; |
| |
| init_rt_bandwidth(&tg->rt_bandwidth, |
| ktime_to_ns(def_rt_bandwidth.rt_period), 0); |
| |
| for_each_possible_cpu(i) { |
| rq = cpu_rq(i); |
| |
| rt_rq = kmalloc_node(sizeof(struct rt_rq), |
| GFP_KERNEL|__GFP_ZERO, cpu_to_node(i)); |
| if (!rt_rq) |
| goto err; |
| |
| rt_se = kmalloc_node(sizeof(struct sched_rt_entity), |
| GFP_KERNEL|__GFP_ZERO, cpu_to_node(i)); |
| if (!rt_se) |
| goto err; |
| |
| parent_se = parent ? parent->rt_se[i] : NULL; |
| init_tg_rt_entry(tg, rt_rq, rt_se, i, 0, parent_se); |
| } |
| |
| return 1; |
| |
| err: |
| return 0; |
| } |
| |
| static inline void register_rt_sched_group(struct task_group *tg, int cpu) |
| { |
| list_add_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list, |
| &cpu_rq(cpu)->leaf_rt_rq_list); |
| } |
| |
| static inline void unregister_rt_sched_group(struct task_group *tg, int cpu) |
| { |
| list_del_rcu(&tg->rt_rq[cpu]->leaf_rt_rq_list); |
| } |
| #else /* !CONFIG_RT_GROUP_SCHED */ |
| static inline void free_rt_sched_group(struct task_group *tg) |
| { |
| } |
| |
| static inline |
| int alloc_rt_sched_group(struct task_group *tg, struct task_group *parent) |
| { |
| return 1; |
| } |
| |
| static inline void register_rt_sched_group(struct task_group *tg, int cpu) |
| { |
| } |
| |
| static inline void unregister_rt_sched_group(struct task_group *tg, int cpu) |
| { |
| } |
| #endif /* CONFIG_RT_GROUP_SCHED */ |
| |
| #ifdef CONFIG_GROUP_SCHED |
| static void free_sched_group(struct task_group *tg) |
| { |
| free_fair_sched_group(tg); |
| free_rt_sched_group(tg); |
| kfree(tg); |
| } |
| |
| /* allocate runqueue etc for a new task group */ |
| struct task_group *sched_create_group(struct task_group *parent) |
| { |
| struct task_group *tg; |
| unsigned long flags; |
| int i; |
| |
| tg = kzalloc(sizeof(*tg), GFP_KERNEL); |
| if (!tg) |
| return ERR_PTR(-ENOMEM); |
| |
| if (!alloc_fair_sched_group(tg, parent)) |
| goto err; |
| |
| if (!alloc_rt_sched_group(tg, parent)) |
| goto err; |
| |
| spin_lock_irqsave(&task_group_lock, flags); |
| for_each_possible_cpu(i) { |
| register_fair_sched_group(tg, i); |
| register_rt_sched_group(tg, i); |
| } |
| list_add_rcu(&tg->list, &task_groups); |
| |
| WARN_ON(!parent); /* root should already exist */ |
| |
| tg->parent = parent; |
| list_add_rcu(&tg->siblings, &parent->children); |
| INIT_LIST_HEAD(&tg->children); |
| spin_unlock_irqrestore(&task_group_lock, flags); |
| |
| return tg; |
| |
| err: |
| free_sched_group(tg); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| /* rcu callback to free various structures associated with a task group */ |
| static void free_sched_group_rcu(struct rcu_head *rhp) |
| { |
| /* now it should be safe to free those cfs_rqs */ |
| free_sched_group(container_of(rhp, struct task_group, rcu)); |
| } |
| |
| /* Destroy runqueue etc associated with a task group */ |
| void sched_destroy_group(struct task_group *tg) |
| { |
| unsigned long flags; |
| int i; |
| |
| spin_lock_irqsave(&task_group_lock, flags); |
| for_each_possible_cpu(i) { |
| unregister_fair_sched_group(tg, i); |
| unregister_rt_sched_group(tg, i); |
| } |
| list_del_rcu(&tg->list); |
| list_del_rcu(&tg->siblings); |
| spin_unlock_irqrestore(&task_group_lock, flags); |
| |
| /* wait for possible concurrent references to cfs_rqs complete */ |
| call_rcu(&tg->rcu, free_sched_group_rcu); |
| } |
| |
| /* change task's runqueue when it moves between groups. |
| * The caller of this function should have put the task in its new group |
| * by now. This function just updates tsk->se.cfs_rq and tsk->se.parent to |
| * reflect its new group. |
| */ |
| void sched_move_task(struct task_struct *tsk) |
| { |
| int on_rq, running; |
| unsigned long flags; |
| struct rq *rq; |
| |
| rq = task_rq_lock(tsk, &flags); |
| |
| update_rq_clock(rq); |
| |
| running = task_current(rq, tsk); |
| on_rq = tsk->se.on_rq; |
| |
| if (on_rq) |
| dequeue_task(rq, tsk, 0); |
| if (unlikely(running)) |
| tsk->sched_class->put_prev_task(rq, tsk); |
| |
| set_task_rq(tsk, task_cpu(tsk)); |
| |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| if (tsk->sched_class->moved_group) |
| tsk->sched_class->moved_group(tsk); |
| #endif |
| |
| if (unlikely(running)) |
| tsk->sched_class->set_curr_task(rq); |
| if (on_rq) |
| enqueue_task(rq, tsk, 0); |
| |
| task_rq_unlock(rq, &flags); |
| } |
| #endif /* CONFIG_GROUP_SCHED */ |
| |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| static void __set_se_shares(struct sched_entity *se, unsigned long shares) |
| { |
| struct cfs_rq *cfs_rq = se->cfs_rq; |
| int on_rq; |
| |
| on_rq = se->on_rq; |
| if (on_rq) |
| dequeue_entity(cfs_rq, se, 0); |
| |
| se->load.weight = shares; |
| se->load.inv_weight = 0; |
| |
| if (on_rq) |
| enqueue_entity(cfs_rq, se, 0); |
| } |
| |
| static void set_se_shares(struct sched_entity *se, unsigned long shares) |
| { |
| struct cfs_rq *cfs_rq = se->cfs_rq; |
| struct rq *rq = cfs_rq->rq; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&rq->lock, flags); |
| __set_se_shares(se, shares); |
| spin_unlock_irqrestore(&rq->lock, flags); |
| } |
| |
| static DEFINE_MUTEX(shares_mutex); |
| |
| int sched_group_set_shares(struct task_group *tg, unsigned long shares) |
| { |
| int i; |
| unsigned long flags; |
| |
| /* |
| * We can't change the weight of the root cgroup. |
| */ |
| if (!tg->se[0]) |
| return -EINVAL; |
| |
| if (shares < MIN_SHARES) |
| shares = MIN_SHARES; |
| else if (shares > MAX_SHARES) |
| shares = MAX_SHARES; |
| |
| mutex_lock(&shares_mutex); |
| if (tg->shares == shares) |
| goto done; |
| |
| spin_lock_irqsave(&task_group_lock, flags); |
| for_each_possible_cpu(i) |
| unregister_fair_sched_group(tg, i); |
| list_del_rcu(&tg->siblings); |
| spin_unlock_irqrestore(&task_group_lock, flags); |
| |
| /* wait for any ongoing reference to this group to finish */ |
| synchronize_sched(); |
| |
| /* |
| * Now we are free to modify the group's share on each cpu |
| * w/o tripping rebalance_share or load_balance_fair. |
| */ |
| tg->shares = shares; |
| for_each_possible_cpu(i) { |
| /* |
| * force a rebalance |
| */ |
| cfs_rq_set_shares(tg->cfs_rq[i], 0); |
| set_se_shares(tg->se[i], shares); |
| } |
| |
| /* |
| * Enable load balance activity on this group, by inserting it back on |
| * each cpu's rq->leaf_cfs_rq_list. |
| */ |
| spin_lock_irqsave(&task_group_lock, flags); |
| for_each_possible_cpu(i) |
| register_fair_sched_group(tg, i); |
| list_add_rcu(&tg->siblings, &tg->parent->children); |
| spin_unlock_irqrestore(&task_group_lock, flags); |
| done: |
| mutex_unlock(&shares_mutex); |
| return 0; |
| } |
| |
| unsigned long sched_group_shares(struct task_group *tg) |
| { |
| return tg->shares; |
| } |
| #endif |
| |
| #ifdef CONFIG_RT_GROUP_SCHED |
| /* |
| * Ensure that the real time constraints are schedulable. |
| */ |
| static DEFINE_MUTEX(rt_constraints_mutex); |
| |
| static unsigned long to_ratio(u64 period, u64 runtime) |
| { |
| if (runtime == RUNTIME_INF) |
| return 1ULL << 16; |
| |
| return div64_u64(runtime << 16, period); |
| } |
| |
| #ifdef CONFIG_CGROUP_SCHED |
| static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) |
| { |
| struct task_group *tgi, *parent = tg->parent; |
| unsigned long total = 0; |
| |
| if (!parent) { |
| if (global_rt_period() < period) |
| return 0; |
| |
| return to_ratio(period, runtime) < |
| to_ratio(global_rt_period(), global_rt_runtime()); |
| } |
| |
| if (ktime_to_ns(parent->rt_bandwidth.rt_period) < period) |
| return 0; |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(tgi, &parent->children, siblings) { |
| if (tgi == tg) |
| continue; |
| |
| total += to_ratio(ktime_to_ns(tgi->rt_bandwidth.rt_period), |
| tgi->rt_bandwidth.rt_runtime); |
| } |
| rcu_read_unlock(); |
| |
| return total + to_ratio(period, runtime) <= |
| to_ratio(ktime_to_ns(parent->rt_bandwidth.rt_period), |
| parent->rt_bandwidth.rt_runtime); |
| } |
| #elif defined CONFIG_USER_SCHED |
| static int __rt_schedulable(struct task_group *tg, u64 period, u64 runtime) |
| { |
| struct task_group *tgi; |
| unsigned long total = 0; |
| unsigned long global_ratio = |
| to_ratio(global_rt_period(), global_rt_runtime()); |
| |
| rcu_read_lock(); |
| list_for_each_entry_rcu(tgi, &task_groups, list) { |
| if (tgi == tg) |
| continue; |
| |
| total += to_ratio(ktime_to_ns(tgi->rt_bandwidth.rt_period), |
| tgi->rt_bandwidth.rt_runtime); |
| } |
| rcu_read_unlock(); |
| |
| return total + to_ratio(period, runtime) < global_ratio; |
| } |
| #endif |
| |
| /* Must be called with tasklist_lock held */ |
| static inline int tg_has_rt_tasks(struct task_group *tg) |
| { |
| struct task_struct *g, *p; |
| do_each_thread(g, p) { |
| if (rt_task(p) && rt_rq_of_se(&p->rt)->tg == tg) |
| return 1; |
| } while_each_thread(g, p); |
| return 0; |
| } |
| |
| static int tg_set_bandwidth(struct task_group *tg, |
| u64 rt_period, u64 rt_runtime) |
| { |
| int i, err = 0; |
| |
| mutex_lock(&rt_constraints_mutex); |
| read_lock(&tasklist_lock); |
| if (rt_runtime == 0 && tg_has_rt_tasks(tg)) { |
| err = -EBUSY; |
| goto unlock; |
| } |
| if (!__rt_schedulable(tg, rt_period, rt_runtime)) { |
| err = -EINVAL; |
| goto unlock; |
| } |
| |
| spin_lock_irq(&tg->rt_bandwidth.rt_runtime_lock); |
| tg->rt_bandwidth.rt_period = ns_to_ktime(rt_period); |
| tg->rt_bandwidth.rt_runtime = rt_runtime; |
| |
| for_each_possible_cpu(i) { |
| struct rt_rq *rt_rq = tg->rt_rq[i]; |
| |
| spin_lock(&rt_rq->rt_runtime_lock); |
| rt_rq->rt_runtime = rt_runtime; |
| spin_unlock(&rt_rq->rt_runtime_lock); |
| } |
| spin_unlock_irq(&tg->rt_bandwidth.rt_runtime_lock); |
| unlock: |
| read_unlock(&tasklist_lock); |
| mutex_unlock(&rt_constraints_mutex); |
| |
| return err; |
| } |
| |
| int sched_group_set_rt_runtime(struct task_group *tg, long rt_runtime_us) |
| { |
| u64 rt_runtime, rt_period; |
| |
| rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); |
| rt_runtime = (u64)rt_runtime_us * NSEC_PER_USEC; |
| if (rt_runtime_us < 0) |
| rt_runtime = RUNTIME_INF; |
| |
| return tg_set_bandwidth(tg, rt_period, rt_runtime); |
| } |
| |
| long sched_group_rt_runtime(struct task_group *tg) |
| { |
| u64 rt_runtime_us; |
| |
| if (tg->rt_bandwidth.rt_runtime == RUNTIME_INF) |
| return -1; |
| |
| rt_runtime_us = tg->rt_bandwidth.rt_runtime; |
| do_div(rt_runtime_us, NSEC_PER_USEC); |
| return rt_runtime_us; |
| } |
| |
| int sched_group_set_rt_period(struct task_group *tg, long rt_period_us) |
| { |
| u64 rt_runtime, rt_period; |
| |
| rt_period = (u64)rt_period_us * NSEC_PER_USEC; |
| rt_runtime = tg->rt_bandwidth.rt_runtime; |
| |
| if (rt_period == 0) |
| return -EINVAL; |
| |
| return tg_set_bandwidth(tg, rt_period, rt_runtime); |
| } |
| |
| long sched_group_rt_period(struct task_group *tg) |
| { |
| u64 rt_period_us; |
| |
| rt_period_us = ktime_to_ns(tg->rt_bandwidth.rt_period); |
| do_div(rt_period_us, NSEC_PER_USEC); |
| return rt_period_us; |
| } |
| |
| static int sched_rt_global_constraints(void) |
| { |
| struct task_group *tg = &root_task_group; |
| u64 rt_runtime, rt_period; |
| int ret = 0; |
| |
| rt_period = ktime_to_ns(tg->rt_bandwidth.rt_period); |
| rt_runtime = tg->rt_bandwidth.rt_runtime; |
| |
| mutex_lock(&rt_constraints_mutex); |
| if (!__rt_schedulable(tg, rt_period, rt_runtime)) |
| ret = -EINVAL; |
| mutex_unlock(&rt_constraints_mutex); |
| |
| return ret; |
| } |
| #else /* !CONFIG_RT_GROUP_SCHED */ |
| static int sched_rt_global_constraints(void) |
| { |
| unsigned long flags; |
| int i; |
| |
| spin_lock_irqsave(&def_rt_bandwidth.rt_runtime_lock, flags); |
| for_each_possible_cpu(i) { |
| struct rt_rq *rt_rq = &cpu_rq(i)->rt; |
| |
| spin_lock(&rt_rq->rt_runtime_lock); |
| rt_rq->rt_runtime = global_rt_runtime(); |
| spin_unlock(&rt_rq->rt_runtime_lock); |
| } |
| spin_unlock_irqrestore(&def_rt_bandwidth.rt_runtime_lock, flags); |
| |
| return 0; |
| } |
| #endif /* CONFIG_RT_GROUP_SCHED */ |
| |
| int sched_rt_handler(struct ctl_table *table, int write, |
| struct file *filp, void __user *buffer, size_t *lenp, |
| loff_t *ppos) |
| { |
| int ret; |
| int old_period, old_runtime; |
| static DEFINE_MUTEX(mutex); |
| |
| mutex_lock(&mutex); |
| old_period = sysctl_sched_rt_period; |
| old_runtime = sysctl_sched_rt_runtime; |
| |
| ret = proc_dointvec(table, write, filp, buffer, lenp, ppos); |
| |
| if (!ret && write) { |
| ret = sched_rt_global_constraints(); |
| if (ret) { |
| sysctl_sched_rt_period = old_period; |
| sysctl_sched_rt_runtime = old_runtime; |
| } else { |
| def_rt_bandwidth.rt_runtime = global_rt_runtime(); |
| def_rt_bandwidth.rt_period = |
| ns_to_ktime(global_rt_period()); |
| } |
| } |
| mutex_unlock(&mutex); |
| |
| return ret; |
| } |
| |
| #ifdef CONFIG_CGROUP_SCHED |
| |
| /* return corresponding task_group object of a cgroup */ |
| static inline struct task_group *cgroup_tg(struct cgroup *cgrp) |
| { |
| return container_of(cgroup_subsys_state(cgrp, cpu_cgroup_subsys_id), |
| struct task_group, css); |
| } |
| |
| static struct cgroup_subsys_state * |
| cpu_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cgrp) |
| { |
| struct task_group *tg, *parent; |
| |
| if (!cgrp->parent) { |
| /* This is early initialization for the top cgroup */ |
| init_task_group.css.cgroup = cgrp; |
| return &init_task_group.css; |
| } |
| |
| parent = cgroup_tg(cgrp->parent); |
| tg = sched_create_group(parent); |
| if (IS_ERR(tg)) |
| return ERR_PTR(-ENOMEM); |
| |
| /* Bind the cgroup to task_group object we just created */ |
| tg->css.cgroup = cgrp; |
| |
| return &tg->css; |
| } |
| |
| static void |
| cpu_cgroup_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) |
| { |
| struct task_group *tg = cgroup_tg(cgrp); |
| |
| sched_destroy_group(tg); |
| } |
| |
| static int |
| cpu_cgroup_can_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, |
| struct task_struct *tsk) |
| { |
| #ifdef CONFIG_RT_GROUP_SCHED |
| /* Don't accept realtime tasks when there is no way for them to run */ |
| if (rt_task(tsk) && cgroup_tg(cgrp)->rt_bandwidth.rt_runtime == 0) |
| return -EINVAL; |
| #else |
| /* We don't support RT-tasks being in separate groups */ |
| if (tsk->sched_class != &fair_sched_class) |
| return -EINVAL; |
| #endif |
| |
| return 0; |
| } |
| |
| static void |
| cpu_cgroup_attach(struct cgroup_subsys *ss, struct cgroup *cgrp, |
| struct cgroup *old_cont, struct task_struct *tsk) |
| { |
| sched_move_task(tsk); |
| } |
| |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| static int cpu_shares_write_u64(struct cgroup *cgrp, struct cftype *cftype, |
| u64 shareval) |
| { |
| return sched_group_set_shares(cgroup_tg(cgrp), shareval); |
| } |
| |
| static u64 cpu_shares_read_u64(struct cgroup *cgrp, struct cftype *cft) |
| { |
| struct task_group *tg = cgroup_tg(cgrp); |
| |
| return (u64) tg->shares; |
| } |
| #endif /* CONFIG_FAIR_GROUP_SCHED */ |
| |
| #ifdef CONFIG_RT_GROUP_SCHED |
| static int cpu_rt_runtime_write(struct cgroup *cgrp, struct cftype *cft, |
| s64 val) |
| { |
| return sched_group_set_rt_runtime(cgroup_tg(cgrp), val); |
| } |
| |
| static s64 cpu_rt_runtime_read(struct cgroup *cgrp, struct cftype *cft) |
| { |
| return sched_group_rt_runtime(cgroup_tg(cgrp)); |
| } |
| |
| static int cpu_rt_period_write_uint(struct cgroup *cgrp, struct cftype *cftype, |
| u64 rt_period_us) |
| { |
| return sched_group_set_rt_period(cgroup_tg(cgrp), rt_period_us); |
| } |
| |
| static u64 cpu_rt_period_read_uint(struct cgroup *cgrp, struct cftype *cft) |
| { |
| return sched_group_rt_period(cgroup_tg(cgrp)); |
| } |
| #endif /* CONFIG_RT_GROUP_SCHED */ |
| |
| static struct cftype cpu_files[] = { |
| #ifdef CONFIG_FAIR_GROUP_SCHED |
| { |
| .name = "shares", |
| .read_u64 = cpu_shares_read_u64, |
| .write_u64 = cpu_shares_write_u64, |
| }, |
| #endif |
| #ifdef CONFIG_RT_GROUP_SCHED |
| { |
| .name = "rt_runtime_us", |
| .read_s64 = cpu_rt_runtime_read, |
| .write_s64 = cpu_rt_runtime_write, |
| }, |
| { |
| .name = "rt_period_us", |
| .read_u64 = cpu_rt_period_read_uint, |
| .write_u64 = cpu_rt_period_write_uint, |
| }, |
| #endif |
| }; |
| |
| static int cpu_cgroup_populate(struct cgroup_subsys *ss, struct cgroup *cont) |
| { |
| return cgroup_add_files(cont, ss, cpu_files, ARRAY_SIZE(cpu_files)); |
| } |
| |
| struct cgroup_subsys cpu_cgroup_subsys = { |
| .name = "cpu", |
| .create = cpu_cgroup_create, |
| .destroy = cpu_cgroup_destroy, |
| .can_attach = cpu_cgroup_can_attach, |
| .attach = cpu_cgroup_attach, |
| .populate = cpu_cgroup_populate, |
| .subsys_id = cpu_cgroup_subsys_id, |
| .early_init = 1, |
| }; |
| |
| #endif /* CONFIG_CGROUP_SCHED */ |
| |
| #ifdef CONFIG_CGROUP_CPUACCT |
| |
| /* |
| * CPU accounting code for task groups. |
| * |
| * Based on the work by Paul Menage (menage@google.com) and Balbir Singh |
| * (balbir@in.ibm.com). |
| */ |
| |
| /* track cpu usage of a group of tasks */ |
| struct cpuacct { |
| struct cgroup_subsys_state css; |
| /* cpuusage holds pointer to a u64-type object on every cpu */ |
| u64 *cpuusage; |
| }; |
| |
| struct cgroup_subsys cpuacct_subsys; |
| |
| /* return cpu accounting group corresponding to this container */ |
| static inline struct cpuacct *cgroup_ca(struct cgroup *cgrp) |
| { |
| return container_of(cgroup_subsys_state(cgrp, cpuacct_subsys_id), |
| struct cpuacct, css); |
| } |
| |
| /* return cpu accounting group to which this task belongs */ |
| static inline struct cpuacct *task_ca(struct task_struct *tsk) |
| { |
| return container_of(task_subsys_state(tsk, cpuacct_subsys_id), |
| struct cpuacct, css); |
| } |
| |
| /* create a new cpu accounting group */ |
| static struct cgroup_subsys_state *cpuacct_create( |
| struct cgroup_subsys *ss, struct cgroup *cgrp) |
| { |
| struct cpuacct *ca = kzalloc(sizeof(*ca), GFP_KERNEL); |
| |
| if (!ca) |
| return ERR_PTR(-ENOMEM); |
| |
| ca->cpuusage = alloc_percpu(u64); |
| if (!ca->cpuusage) { |
| kfree(ca); |
| return ERR_PTR(-ENOMEM); |
| } |
| |
| return &ca->css; |
| } |
| |
| /* destroy an existing cpu accounting group */ |
| static void |
| cpuacct_destroy(struct cgroup_subsys *ss, struct cgroup *cgrp) |
| { |
| struct cpuacct *ca = cgroup_ca(cgrp); |
| |
| free_percpu(ca->cpuusage); |
| kfree(ca); |
| } |
| |
| /* return total cpu usage (in nanoseconds) of a group */ |
| static u64 cpuusage_read(struct cgroup *cgrp, struct cftype *cft) |
| { |
| struct cpuacct *ca = cgroup_ca(cgrp); |
| u64 totalcpuusage = 0; |
| int i; |
| |
| for_each_possible_cpu(i) { |
| u64 *cpuusage = percpu_ptr(ca->cpuusage, i); |
| |
| /* |
| * Take rq->lock to make 64-bit addition safe on 32-bit |
| * platforms. |
| */ |
| spin_lock_irq(&cpu_rq(i)->lock); |
| totalcpuusage += *cpuusage; |
| spin_unlock_irq(&cpu_rq(i)->lock); |
| } |
| |
| return totalcpuusage; |
| } |
| |
| static int cpuusage_write(struct cgroup *cgrp, struct cftype *cftype, |
| u64 reset) |
| { |
| struct cpuacct *ca = cgroup_ca(cgrp); |
| int err = 0; |
| int i; |
| |
| if (reset) { |
| err = -EINVAL; |
| goto out; |
| } |
| |
| for_each_possible_cpu(i) { |
| u64 *cpuusage = percpu_ptr(ca->cpuusage, i); |
| |
| spin_lock_irq(&cpu_rq(i)->lock); |
| *cpuusage = 0; |
| spin_unlock_irq(&cpu_rq(i)->lock); |
| } |
| out: |
| return err; |
| } |
| |
| static struct cftype files[] = { |
| { |
| .name = "usage", |
| .read_u64 = cpuusage_read, |
| .write_u64 = cpuusage_write, |
| }, |
| }; |
| |
| static int cpuacct_populate(struct cgroup_subsys *ss, struct cgroup *cgrp) |
| { |
| return cgroup_add_files(cgrp, ss, files, ARRAY_SIZE(files)); |
| } |
| |
| /* |
| * charge this task's execution time to its accounting group. |
| * |
| * called with rq->lock held. |
| */ |
| static void cpuacct_charge(struct task_struct *tsk, u64 cputime) |
| { |
| struct cpuacct *ca; |
| |
| if (!cpuacct_subsys.active) |
| return; |
| |
| ca = task_ca(tsk); |
| if (ca) { |
| u64 *cpuusage = percpu_ptr(ca->cpuusage, task_cpu(tsk)); |
| |
| *cpuusage += cputime; |
| } |
| } |
| |
| struct cgroup_subsys cpuacct_subsys = { |
| .name = "cpuacct", |
| .create = cpuacct_create, |
| .destroy = cpuacct_destroy, |
| .populate = cpuacct_populate, |
| .subsys_id = cpuacct_subsys_id, |
| }; |
| #endif /* CONFIG_CGROUP_CPUACCT */ |