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| author | Peter Zijlstra <peterz@infradead.org> | 2021-12-25 01:04:57 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-02-16 12:56:11 +0100 |
| commit | 85008bde411d5be480d3926ec3fb26b93d46001f (patch) | |
| tree | 148e6f3f179b155dd902b5649a6f73b509cd6dee /kernel/sched/core.c | |
| parent | ec903b6daa586dedff31c27d6b7d8d84cbd11131 (diff) | |
| download | linux-stable-85008bde411d5be480d3926ec3fb26b93d46001f.tar.gz linux-stable-85008bde411d5be480d3926ec3fb26b93d46001f.tar.bz2 linux-stable-85008bde411d5be480d3926ec3fb26b93d46001f.zip | |
sched: Avoid double preemption in __cond_resched_*lock*()
[ Upstream commit 7e406d1ff39b8ee574036418a5043c86723170cf ]
For PREEMPT/DYNAMIC_PREEMPT the *_unlock() will already trigger a
preemption, no point in then calling preempt_schedule_common()
*again*.
Use _cond_resched() instead, since this is a NOP for the preemptible
configs while it provide a preemption point for the others.
Reported-by: xuhaifeng <xuhaifeng@oppo.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/YcGnvDEYBwOiV0cR@hirez.programming.kicks-ass.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
Diffstat (limited to 'kernel/sched/core.c')
| -rw-r--r-- | kernel/sched/core.c | 12 |
1 files changed, 3 insertions, 9 deletions
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0d12ec7be301..c2dec6ce9809 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -8199,9 +8199,7 @@ int __cond_resched_lock(spinlock_t *lock) if (spin_needbreak(lock) || resched) { spin_unlock(lock); - if (resched) - preempt_schedule_common(); - else + if (!_cond_resched()) cpu_relax(); ret = 1; spin_lock(lock); @@ -8219,9 +8217,7 @@ int __cond_resched_rwlock_read(rwlock_t *lock) if (rwlock_needbreak(lock) || resched) { read_unlock(lock); - if (resched) - preempt_schedule_common(); - else + if (!_cond_resched()) cpu_relax(); ret = 1; read_lock(lock); @@ -8239,9 +8235,7 @@ int __cond_resched_rwlock_write(rwlock_t *lock) if (rwlock_needbreak(lock) || resched) { write_unlock(lock); - if (resched) - preempt_schedule_common(); - else + if (!_cond_resched()) cpu_relax(); ret = 1; write_lock(lock); |