In order to avoid the false positive from lockdep, each per-cpu base->lock has
the separate lock class and migrate_timers() uses double_spin_lock().
This all is overcomplicated: except for migrate_timers() we never take 2 locks
at once, and migrate_timers() can use spin_lock_nested().
Signed-off-by: Oleg Nesterov <[EMAIL PROTECTED]>
--- 25/kernel/timer.c~2_TIMERS 2008-02-15 16:59:18.000000000 +0300
+++ 25/kernel/timer.c 2008-02-15 19:17:29.000000000 +0300
@@ -1220,13 +1220,6 @@ asmlinkage long sys_sysinfo(struct sysin
return 0;
}
-/*
- * lockdep: we want to track each per-CPU base as a separate lock-class,
- * but timer-bases are kmalloc()-ed, so we need to attach separate
- * keys to them:
- */
-static struct lock_class_key base_lock_keys[NR_CPUS];
-
static int __cpuinit init_timers_cpu(int cpu)
{
int j;
@@ -1269,7 +1262,6 @@ static int __cpuinit init_timers_cpu(int
}
spin_lock_init(&base->lock);
- lockdep_set_class(&base->lock, base_lock_keys + cpu);
for (j = 0; j < TVN_SIZE; j++) {
INIT_LIST_HEAD(base->tv5.vec + j);
@@ -1308,8 +1300,8 @@ static void __cpuinit migrate_timers(int
new_base = get_cpu_var(tvec_bases);
local_irq_disable();
- double_spin_lock(&new_base->lock, &old_base->lock,
- smp_processor_id() < cpu);
+ spin_lock(&new_base->lock);
+ spin_lock_nested(&old_base->lock, SINGLE_DEPTH_NESTING);
BUG_ON(old_base->running_timer);
@@ -1322,8 +1314,8 @@ static void __cpuinit migrate_timers(int
migrate_timer_list(new_base, old_base->tv5.vec + i);
}
- double_spin_unlock(&new_base->lock, &old_base->lock,
- smp_processor_id() < cpu);
+ spin_unlock(&old_base->lock);
+ spin_unlock(&new_base->lock);
local_irq_enable();
put_cpu_var(tvec_bases);
}
--
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