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| author |   Herbert Xu <herbert@gondor.apana.org.au> | 2008-01-25 21:08:28 +0100 |
|---|---|---|
| committer |   Ingo Molnar <mingo@elte.hu> | 2008-01-25 21:08:28 +0100 |
| commit | 02b67cc3ba36bdba351d6c3a00593f4ec550d9d3 (patch) | |
| tree | 5185ad2d780974dc864f12d81d6c8b9fec73097b | |
| parent | sched: documentation, whitespace fixes (diff) | |
| download | linux-dev-02b67cc3ba36bdba351d6c3a00593f4ec550d9d3.tar.xz linux-dev-02b67cc3ba36bdba351d6c3a00593f4ec550d9d3.zip | |
sched: do not do cond_resched() when CONFIG_PREEMPT
Why do we even have cond_resched when real preemption
is on? It seems to be a waste of space and time.
remove cond_resched with CONFIG_PREEMPT on.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | include/linux/kernel.h | 4 | ||||
| -rw-r--r-- | include/linux/sched.h | 13 | ||||
| -rw-r--r-- | kernel/sched.c | 6 |
3 files changed, 18 insertions, 5 deletions
diff --git a/include/linux/kernel.h b/include/linux/kernel.h index 94bc99656963..a7283c9beadf 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -105,8 +105,8 @@ struct user; * supposed to. */ #ifdef CONFIG_PREEMPT_VOLUNTARY -extern int cond_resched(void); -# define might_resched() cond_resched() +extern int _cond_resched(void); +# define might_resched() _cond_resched() #else # define might_resched() do { } while (0) #endif diff --git a/include/linux/sched.h b/include/linux/sched.h index fe3f8fbc614e..7907845c2348 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1885,7 +1885,18 @@ 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(); +} +#endif extern int cond_resched_lock(spinlock_t * lock); extern int cond_resched_softirq(void); diff --git a/kernel/sched.c b/kernel/sched.c index b9ee0f4db66a..6ee37602a6d8 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -4678,7 +4678,8 @@ static void __cond_resched(void) } while (need_resched()); } -int __sched cond_resched(void) +#if !defined(CONFIG_PREEMPT) || defined(CONFIG_PREEMPT_VOLUNTARY) +int __sched _cond_resched(void) { if (need_resched() && !(preempt_count() & PREEMPT_ACTIVE) && system_state == SYSTEM_RUNNING) { @@ -4687,7 +4688,8 @@ int __sched cond_resched(void) } return 0; } -EXPORT_SYMBOL(cond_resched); +EXPORT_SYMBOL(_cond_resched); +#endif /* * cond_resched_lock() - if a reschedule is pending, drop the given lock, |