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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>
hifive-unleashed-5.1
Frederic Weisbecker 2009-07-16 15:44:29 +02:00 committed by Ingo Molnar
parent e09758fae8
commit e4aafea2d4
2 changed files with 14 additions and 7 deletions
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6
include/linux/kernel.h
View File

@ -125,7 +125,7 @@ extern int _cond_resched(void);
#endif #endif
#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP #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 * might_sleep - annotation for functions that can sleep
* *
@ -137,9 +137,9 @@ extern int _cond_resched(void);
* supposed to. * supposed to.
*/ */
# define might_sleep() \ # define might_sleep() \
do { __might_sleep(__FILE__, __LINE__); might_resched(); } while (0) do { __might_sleep(__FILE__, __LINE__, 0); might_resched(); } while (0)
#else #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) # define might_sleep() do { might_resched(); } while (0)
#endif #endif

15
kernel/sched.c
View File

@ -6610,7 +6610,7 @@ static inline int should_resched(void)
static void __cond_resched(void) static void __cond_resched(void)
{ {
__might_sleep(__FILE__, __LINE__); __might_sleep(__FILE__, __LINE__, 0);
add_preempt_count(PREEMPT_ACTIVE); add_preempt_count(PREEMPT_ACTIVE);
schedule(); schedule();
@ -9429,13 +9429,20 @@ void __init sched_init(void)
} }
#ifdef CONFIG_DEBUG_SPINLOCK_SLEEP #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 #ifdef in_atomic
static unsigned long prev_jiffy; /* ratelimiting */ static unsigned long prev_jiffy; /* ratelimiting */
if ((!in_atomic() && !irqs_disabled()) || if ((preempt_count_equals(preempt_offset) && !irqs_disabled()) ||
system_state != SYSTEM_RUNNING || oops_in_progress) system_state != SYSTEM_RUNNING || oops_in_progress)
return; return;
if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy) if (time_before(jiffies, prev_jiffy + HZ) && prev_jiffy)
return; return;