From: Peter Zijlstra peterz@infradead.org
[ 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 --- kernel/sched/core.c | 12 +++--------- 1 file changed, 3 insertions(+), 9 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 0d12ec7be3017..c2dec6ce98091 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);