The following commit has been merged into the sched/core branch of tip: Commit-ID: 579df3f2325191322b96906a5898462253a45ede Gitweb: https://git.kernel.org/tip/579df3f2325191322b96906a5898462253a45ede Author: Thomas Gleixner <tglx@xxxxxxxxxxxxx> AuthorDate: Wed, 29 Sep 2021 11:37:32 +02:00 Committer: Peter Zijlstra <peterz@xxxxxxxxxxxxx> CommitterDate: Fri, 01 Oct 2021 13:58:07 +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 8e49b17..d469c7b 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6097,20 +6097,14 @@ 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))
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