From: Thomas Gleixner Date: Wed, 29 Sep 2021 09:37:32 +0000 (+0200) Subject: sched: Remove pointless preemption disable in sched_submit_work() X-Git-Tag: v6.6.17~8991^2~35 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=b945efcdd07d86cece1cce68503aae91f107eacb;p=platform%2Fkernel%2Flinux-rpi.git 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 Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Lai Jiangshan Reviewed-by: Jens Axboe Link: https://lkml.kernel.org/r/8735pnafj7.ffs@tglx --- diff --git a/kernel/sched/core.c b/kernel/sched/core.c index e33b03c2bb9a..e47d7e55c46a 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))