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Add new 'cond_resched_bkl()' helper function

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It acts exactly like a regular 'cond_resched()', but will not get
optimized away when CONFIG_PREEMPT is set.

Normal kernel code is already preemptable in the presense of
CONFIG_PREEMPT, so cond_resched() is optimized away (see commit
02b67cc3ba "sched: do not do
cond_resched() when CONFIG_PREEMPT").

But when wanting to conditionally reschedule while holding a lock, you
need to use "cond_sched_lock(lock)", and the new function is the BKL
equivalent of that.

Also make fs/locks.c use it.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Linus Torvalds
2008-05-11 16:04:48 -07:00
parent 9662369786
commit c3921ab715
3 changed files with 6 additions and 4 deletions
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6
include/linux/sched.h
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@@ -2037,13 +2037,13 @@ static inline int need_resched(void)
* cond_resched_lock() will drop the spinlock before scheduling,
* cond_resched_softirq() will enable bhs before scheduling.
*/
extern int _cond_resched(void);
#ifdef CONFIG_PREEMPT
static inline int cond_resched(void)
{
return 0;
}
#else
extern int _cond_resched(void);
static inline int cond_resched(void)
{
return _cond_resched();
@@ -2051,6 +2051,10 @@ static inline int cond_resched(void)
#endif
extern int cond_resched_lock(spinlock_t * lock);
extern int cond_resched_softirq(void);
static inline int cond_resched_bkl(void)
{
return _cond_resched();
}
/*
* Does a critical section need to be broken due to another