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authorOleg Nesterov <oleg@tv-sign.ru>2008-04-04 20:54:10 +0200
committerThomas Gleixner <tglx@linutronix.de>2008-04-17 12:22:31 +0200
commit0d180406f2914aea3a78ddb880e2fe9ac78a9372 (patch)
treedeb1f21d29a3ba8e7bdcc186ea78594599fce409 /kernel/timer.c
parentee7dd205b5cdbc3231d48e38641efd05f572c52a (diff)
downloadlwn-0d180406f2914aea3a78ddb880e2fe9ac78a9372.tar.gz
lwn-0d180406f2914aea3a78ddb880e2fe9ac78a9372.zip
timers: simplify lockdep handling
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 <oleg@tv-sign.ru> Cc: Arjan van de Ven <arjan@linux.intel.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'kernel/timer.c')
-rw-r--r--kernel/timer.c16
1 files changed, 4 insertions, 12 deletions
diff --git a/kernel/timer.c b/kernel/timer.c
index b024106daa70..f3d35d4ea42e 100644
--- a/kernel/timer.c
+++ b/kernel/timer.c
@@ -1228,13 +1228,6 @@ asmlinkage long sys_sysinfo(struct sysinfo __user *info)
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;
@@ -1277,7 +1270,6 @@ static int __cpuinit init_timers_cpu(int cpu)
}
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);
@@ -1316,8 +1308,8 @@ static void __cpuinit migrate_timers(int cpu)
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);
@@ -1330,8 +1322,8 @@ static void __cpuinit migrate_timers(int cpu)
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);
}