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| author | Frederic Weisbecker <fweisbec@gmail.com> | 2009-07-16 15:44:29 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-07-18 15:51:42 +0200 |
| commit | e4aafea2d4bde8b44d6500c4ee7195bbfc51269e (patch) | |
| tree | bf0c9df18b9f63bb10da0096d81ba80712a71665 | |
| parent | e09758fae8ccde97e026c704319eaa18d488dc86 (diff) | |
| download | lwn-e4aafea2d4bde8b44d6500c4ee7195bbfc51269e.tar.gz lwn-e4aafea2d4bde8b44d6500c4ee7195bbfc51269e.zip | |
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>
| -rw-r--r-- | include/linux/kernel.h | 6 | ||||
| -rw-r--r-- | kernel/sched.c | 15 |
2 files changed, 14 insertions, 7 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index b804f694ae6a..2b5b1e0899a8 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -125,7 +125,7 @@ extern int _cond_resched(void); #endif #ifdef CONFIG_DEBUG_SPINLOCK_SLEEP - void __might_sleep(char *file, int line); + void __might_sleep(char *file, int line, int preempt_offset); /** * might_sleep - annotation for functions that can sleep * @@ -137,9 +137,9 @@ extern int _cond_resched(void); * supposed to. */ # define might_sleep() \ - do { __might_sleep(__FILE__, __LINE__); might_resched(); } while (0) + do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0) #else - static inline void __might_sleep(char *file, int line) { } + static inline void __might_sleep(char *file, int line, int preempt_offset) { } # define might_sleep() do { might_resched(); } while (0) #endif diff --git a/kernel/sched.c b/kernel/sched.c index 370a6c31c5e1..3ff4d004bd95 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; |