Merge branch 'core-debugobjects-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull debugobjects updates from Ingo Molnar:
"A number of scalability improvements by Waimang Long"
* 'core-debugobjects-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
debugobjects: Improve variable naming
debugobjects: Reduce contention on the global pool_lock
debugobjects: Scale thresholds with # of CPUs
debugobjects: Track number of kmem_cache_alloc/kmem_cache_free done
diff --git a/lib/debugobjects.c b/lib/debugobjects.c
index 04c1ef7..8c28cbd 100644
--- a/lib/debugobjects.c
+++ b/lib/debugobjects.c
@@ -52,9 +52,18 @@ static int debug_objects_fixups __read_mostly;
static int debug_objects_warnings __read_mostly;
static int debug_objects_enabled __read_mostly
= CONFIG_DEBUG_OBJECTS_ENABLE_DEFAULT;
-
+static int debug_objects_pool_size __read_mostly
+ = ODEBUG_POOL_SIZE;
+static int debug_objects_pool_min_level __read_mostly
+ = ODEBUG_POOL_MIN_LEVEL;
static struct debug_obj_descr *descr_test __read_mostly;
+/*
+ * Track numbers of kmem_cache_alloc()/free() calls done.
+ */
+static int debug_objects_allocated;
+static int debug_objects_freed;
+
static void free_obj_work(struct work_struct *work);
static DECLARE_WORK(debug_obj_work, free_obj_work);
@@ -88,13 +97,13 @@ static void fill_pool(void)
struct debug_obj *new;
unsigned long flags;
- if (likely(obj_pool_free >= ODEBUG_POOL_MIN_LEVEL))
+ if (likely(obj_pool_free >= debug_objects_pool_min_level))
return;
if (unlikely(!obj_cache))
return;
- while (obj_pool_free < ODEBUG_POOL_MIN_LEVEL) {
+ while (obj_pool_free < debug_objects_pool_min_level) {
new = kmem_cache_zalloc(obj_cache, gfp);
if (!new)
@@ -102,6 +111,7 @@ static void fill_pool(void)
raw_spin_lock_irqsave(&pool_lock, flags);
hlist_add_head(&new->node, &obj_pool);
+ debug_objects_allocated++;
obj_pool_free++;
raw_spin_unlock_irqrestore(&pool_lock, flags);
}
@@ -162,24 +172,39 @@ alloc_object(void *addr, struct debug_bucket *b, struct debug_obj_descr *descr)
/*
* workqueue function to free objects.
+ *
+ * To reduce contention on the global pool_lock, the actual freeing of
+ * debug objects will be delayed if the pool_lock is busy. We also free
+ * the objects in a batch of 4 for each lock/unlock cycle.
*/
+#define ODEBUG_FREE_BATCH 4
+
static void free_obj_work(struct work_struct *work)
{
- struct debug_obj *obj;
+ struct debug_obj *objs[ODEBUG_FREE_BATCH];
unsigned long flags;
+ int i;
- raw_spin_lock_irqsave(&pool_lock, flags);
- while (obj_pool_free > ODEBUG_POOL_SIZE) {
- obj = hlist_entry(obj_pool.first, typeof(*obj), node);
- hlist_del(&obj->node);
- obj_pool_free--;
+ if (!raw_spin_trylock_irqsave(&pool_lock, flags))
+ return;
+ while (obj_pool_free >= debug_objects_pool_size + ODEBUG_FREE_BATCH) {
+ for (i = 0; i < ODEBUG_FREE_BATCH; i++) {
+ objs[i] = hlist_entry(obj_pool.first,
+ typeof(*objs[0]), node);
+ hlist_del(&objs[i]->node);
+ }
+
+ obj_pool_free -= ODEBUG_FREE_BATCH;
+ debug_objects_freed += ODEBUG_FREE_BATCH;
/*
* We release pool_lock across kmem_cache_free() to
* avoid contention on pool_lock.
*/
raw_spin_unlock_irqrestore(&pool_lock, flags);
- kmem_cache_free(obj_cache, obj);
- raw_spin_lock_irqsave(&pool_lock, flags);
+ for (i = 0; i < ODEBUG_FREE_BATCH; i++)
+ kmem_cache_free(obj_cache, objs[i]);
+ if (!raw_spin_trylock_irqsave(&pool_lock, flags))
+ return;
}
raw_spin_unlock_irqrestore(&pool_lock, flags);
}
@@ -198,7 +223,7 @@ static void free_object(struct debug_obj *obj)
* schedule work when the pool is filled and the cache is
* initialized:
*/
- if (obj_pool_free > ODEBUG_POOL_SIZE && obj_cache)
+ if (obj_pool_free > debug_objects_pool_size && obj_cache)
sched = 1;
hlist_add_head(&obj->node, &obj_pool);
obj_pool_free++;
@@ -758,6 +783,8 @@ static int debug_stats_show(struct seq_file *m, void *v)
seq_printf(m, "pool_min_free :%d\n", obj_pool_min_free);
seq_printf(m, "pool_used :%d\n", obj_pool_used);
seq_printf(m, "pool_max_used :%d\n", obj_pool_max_used);
+ seq_printf(m, "objs_allocated:%d\n", debug_objects_allocated);
+ seq_printf(m, "objs_freed :%d\n", debug_objects_freed);
return 0;
}
@@ -1116,4 +1143,11 @@ void __init debug_objects_mem_init(void)
pr_warn("out of memory.\n");
} else
debug_objects_selftest();
+
+ /*
+ * Increase the thresholds for allocating and freeing objects
+ * according to the number of possible CPUs available in the system.
+ */
+ debug_objects_pool_size += num_possible_cpus() * 32;
+ debug_objects_pool_min_level += num_possible_cpus() * 4;
}
