[PATCH] timer initialisation fix
We need the boot CPU's tvec_bases[] entry to be initialised super-early in
boot, for early_serial_setup(). That runs within setup_arch(), before even
per-cpu areas are initialised.
The patch changes tvec_bases to use compile-time initialisation, and adds a
separate array `tvec_base_done' to keep track of which CPU has had its
tvec_bases[] entry initialised (because we can no longer use the zeroness of
that tvec_bases[] entry to determine whether it has been initialised).
Thanks to Eugene Surovegin <ebs@ebshome.net> for diagnosing this.
Cc: Eugene Surovegin <ebs@ebshome.net>
Cc: Jan Beulich <jbeulich@novell.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/kernel/timer.c b/kernel/timer.c
index 471ab87..8837737 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -81,9 +81,10 @@
} ____cacheline_aligned_in_smp;
typedef struct tvec_t_base_s tvec_base_t;
-static DEFINE_PER_CPU(tvec_base_t *, tvec_bases);
+
tvec_base_t boot_tvec_bases;
EXPORT_SYMBOL(boot_tvec_bases);
+static DEFINE_PER_CPU(tvec_base_t *, tvec_bases) = { &boot_tvec_bases };
static inline void set_running_timer(tvec_base_t *base,
struct timer_list *timer)
@@ -1224,28 +1225,36 @@
{
int j;
tvec_base_t *base;
+ static char __devinitdata tvec_base_done[NR_CPUS];
- base = per_cpu(tvec_bases, cpu);
- if (!base) {
+ if (!tvec_base_done[cpu]) {
static char boot_done;
- /*
- * Cannot do allocation in init_timers as that runs before the
- * allocator initializes (and would waste memory if there are
- * more possible CPUs than will ever be installed/brought up).
- */
if (boot_done) {
+ /*
+ * The APs use this path later in boot
+ */
base = kmalloc_node(sizeof(*base), GFP_KERNEL,
cpu_to_node(cpu));
if (!base)
return -ENOMEM;
memset(base, 0, sizeof(*base));
+ per_cpu(tvec_bases, cpu) = base;
} else {
- base = &boot_tvec_bases;
+ /*
+ * This is for the boot CPU - we use compile-time
+ * static initialisation because per-cpu memory isn't
+ * ready yet and because the memory allocators are not
+ * initialised either.
+ */
boot_done = 1;
+ base = &boot_tvec_bases;
}
- per_cpu(tvec_bases, cpu) = base;
+ tvec_base_done[cpu] = 1;
+ } else {
+ base = per_cpu(tvec_bases, cpu);
}
+
spin_lock_init(&base->lock);
for (j = 0; j < TVN_SIZE; j++) {
INIT_LIST_HEAD(base->tv5.vec + j);
