diff options
author | Peter Zijlstra <peterz@infradead.org> | 2013-11-20 12:22:37 +0100 |
---|---|---|
committer | Ingo Molnar <mingo@kernel.org> | 2014-01-13 17:38:55 +0100 |
commit | 8cb75e0c4ec9786b81439761eac1d18d4a931af3 (patch) | |
tree | 9d13e6c3580a36cd76d1b3a96827795949519409 /include/linux/sched.h | |
parent | c9c8986847d2f4fc474c10ee08afa57e7474096d (diff) | |
download | linux-stable-8cb75e0c4ec9786b81439761eac1d18d4a931af3.tar.gz linux-stable-8cb75e0c4ec9786b81439761eac1d18d4a931af3.tar.bz2 linux-stable-8cb75e0c4ec9786b81439761eac1d18d4a931af3.zip |
sched/preempt: Fix up missed PREEMPT_NEED_RESCHED folding
With various drivers wanting to inject idle time; we get people
calling idle routines outside of the idle loop proper.
Therefore we need to be extra careful about not missing
TIF_NEED_RESCHED -> PREEMPT_NEED_RESCHED propagations.
While looking at this, I also realized there's a small window in the
existing idle loop where we can miss TIF_NEED_RESCHED; when it hits
right after the tif_need_resched() test at the end of the loop but
right before the need_resched() test at the start of the loop.
So move preempt_fold_need_resched() out of the loop where we're
guaranteed to have TIF_NEED_RESCHED set.
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/n/tip-x9jgh45oeayzajz2mjt0y7d6@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'include/linux/sched.h')
-rw-r--r-- | include/linux/sched.h | 15 |
1 files changed, 15 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index a03875221663..ffccdad050b5 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2745,6 +2745,21 @@ static inline bool __must_check current_clr_polling_and_test(void) } #endif +static inline void current_clr_polling(void) +{ + __current_clr_polling(); + + /* + * Ensure we check TIF_NEED_RESCHED after we clear the polling bit. + * Once the bit is cleared, we'll get IPIs with every new + * TIF_NEED_RESCHED and the IPI handler, scheduler_ipi(), will also + * fold. + */ + smp_mb(); /* paired with resched_task() */ + + preempt_fold_need_resched(); +} + static __always_inline bool need_resched(void) { return unlikely(tif_need_resched()); |