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authorFrederic Weisbecker <fweisbec@gmail.com>2009-07-16 15:44:29 +0200
committerIngo Molnar <mingo@elte.hu>2009-07-18 15:51:42 +0200
commite4aafea2d4bde8b44d6500c4ee7195bbfc51269e (patch)
treebf0c9df18b9f63bb10da0096d81ba80712a71665 /kernel/sched.c
parente09758fae8ccde97e026c704319eaa18d488dc86 (diff)
sched: Add a preempt count base offset to __might_sleep()
Add a preempt count base offset to compare against the current preempt level count. It prepares to pull up the might_sleep check from cond_resched() to cond_resched_lock() and cond_resched_bh(). For these two helpers, we need to respectively ensure that once we'll unlock the given spinlock / reenable local softirqs, we will reach a sleepable state. Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> [ Move and rename preempt_count_equals() ] Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1247725694-6082-4-git-send-email-fweisbec@gmail.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r--kernel/sched.c15
1 files changed, 11 insertions, 4 deletions
diff --git a/kernel/sched.c b/kernel/sched.c
index 370a6c31c5e..3ff4d004bd9 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6610,7 +6610,7 @@ static inline int should_resched(void)
static void __cond_resched(void)
{
- __might_sleep(__FILE__, __LINE__);
+ __might_sleep(__FILE__, __LINE__, 0);
add_preempt_count(PREEMPT_ACTIVE);
schedule();
@@ -9429,13 +9429,20 @@ void __init sched_init(void)
}
#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP
-void __might_sleep(char *file, int line)
+static inline int preempt_count_equals(int preempt_offset)
+{
+ int nested = preempt_count() & ~PREEMPT_ACTIVE;
+
+ return (nested == PREEMPT_INATOMIC_BASE + preempt_offset);
+}
+
+void __might_sleep(char *file, int line, int preempt_offset)
{
#ifdef in_atomic
static unsigned long prev_jiffy; /* ratelimiting */
- if ((!in_atomic() && !irqs_disabled()) ||
- system_state != SYSTEM_RUNNING || oops_in_progress)
+ if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
+ system_state != SYSTEM_RUNNING || oops_in_progress)
return;
if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
return;