The following commit has been merged into the sched/core branch of tip:
Commit-ID: b945efcdd07d86cece1cce68503aae91f107eacb
Gitweb: https://git.kernel.org/tip/b945efcdd07d86cece1cce68503aae91f107eacb
Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
AuthorDate: Wed, 29 Sep 2021 11:37:32 +02:00
Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
CommitterDate: Tue, 05 Oct 2021 15:52:15 +02:00
sched: Remove pointless preemption disable in sched_submit_work()
Neither wq_worker_sleeping() nor io_wq_worker_sleeping() require to be invoked
with preemption disabled:
- The worker flag checks operations only need to be serialized against
the worker thread itself.
- The accounting and worker pool operations are serialized with locks.
which means that disabling preemption has neither a reason nor a
value. Remove it and update the stale comment.
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Reviewed-by: Lai Jiangshan <jiangshanlai@xxxxxxxxx>
Reviewed-by: Jens Axboe <axboe@xxxxxxxxx>
Link: https://lkml.kernel.org/r/8735pnafj7.ffs@tglx
---
kernel/sched/core.c | 10 ++--------
1 file changed, 2 insertions(+), 8 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index e33b03c..e47d7e5 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -6251,20 +6251,14 @@ static inline void sched_submit_work(struct task_struct *tsk)
task_flags = tsk->flags;
/*
- * If a worker went to sleep, notify and ask workqueue whether
- * it wants to wake up a task to maintain concurrency.
- * As this function is called inside the schedule() context,
- * we disable preemption to avoid it calling schedule() again
- * in the possible wakeup of a kworker and because wq_worker_sleeping()
- * requires it.
+ * If a worker goes to sleep, notify and ask workqueue whether it
+ * wants to wake up a task to maintain concurrency.
*/
if (task_flags & (PF_WQ_WORKER | PF_IO_WORKER)) {
- preempt_disable();
if (task_flags & PF_WQ_WORKER)
wq_worker_sleeping(tsk);
else
io_wq_worker_sleeping(tsk);
- preempt_enable_no_resched();
}
if (tsk_is_pi_blocked(tsk))
|