sched: Pull up the might_sleep() check into cond_resched()
might_sleep() is called late-ish in cond_resched(), after the
need_resched()/preempt enabled/system running tests are
checked.
It's better to check the sleeps while atomic earlier and not
depend on some environment datas that reduce the chances to
detect a problem.
Also define cond_resched_*() helpers as macros, so that the
FILE/LINE reported in the sleeping while atomic warning
displays the real origin and not sched.h
Changes in v2:
- Call __might_sleep() directly instead of might_sleep() which
may call cond_resched()
- Turn cond_resched() into a macro so that the file:line
couple reported refers to the caller of cond_resched() and
not __cond_resched() itself.
Changes in v3:
- Also propagate this __might_sleep() pull up to
cond_resched_lock() and cond_resched_softirq()
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1247725694-6082-6-git-send-email-fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/kernel/sched.c b/kernel/sched.c
index 3ff4d00..1f7919a 100644
--- a/kernel/sched.c
+++ b/kernel/sched.c
@@ -6610,8 +6610,6 @@
static void __cond_resched(void)
{
- __might_sleep(__FILE__, __LINE__, 0);
-
add_preempt_count(PREEMPT_ACTIVE);
schedule();
sub_preempt_count(PREEMPT_ACTIVE);
@@ -6628,14 +6626,14 @@
EXPORT_SYMBOL(_cond_resched);
/*
- * cond_resched_lock() - if a reschedule is pending, drop the given lock,
+ * __cond_resched_lock() - if a reschedule is pending, drop the given lock,
* call schedule, and on return reacquire the lock.
*
* This works OK both with and without CONFIG_PREEMPT. We do strange low-level
* operations here to prevent schedule() from being called twice (once via
* spin_unlock(), once by hand).
*/
-int cond_resched_lock(spinlock_t *lock)
+int __cond_resched_lock(spinlock_t *lock)
{
int resched = should_resched();
int ret = 0;
@@ -6651,9 +6649,9 @@
}
return ret;
}
-EXPORT_SYMBOL(cond_resched_lock);
+EXPORT_SYMBOL(__cond_resched_lock);
-int __sched cond_resched_softirq(void)
+int __sched __cond_resched_softirq(void)
{
BUG_ON(!in_softirq());
@@ -6665,7 +6663,7 @@
}
return 0;
}
-EXPORT_SYMBOL(cond_resched_softirq);
+EXPORT_SYMBOL(__cond_resched_softirq);
/**
* yield - yield the current processor to other threads.