From: Yunfeng Ye Date: Thu, 19 Nov 2020 06:21:25 +0000 (+0800) Subject: workqueue: Kick a worker based on the actual activation of delayed works X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=f6d739c476c53585bd56b40492a781d5e43bfc48;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git workqueue: Kick a worker based on the actual activation of delayed works [ Upstream commit 01341fbd0d8d4e717fc1231cdffe00343088ce0b ] In realtime scenario, We do not want to have interference on the isolated cpu cores. but when invoking alloc_workqueue() for percpu wq on the housekeeping cpu, it kick a kworker on the isolated cpu. alloc_workqueue pwq_adjust_max_active wake_up_worker The comment in pwq_adjust_max_active() said: "Need to kick a worker after thawed or an unbound wq's max_active is bumped" So it is unnecessary to kick a kworker for percpu's wq when invoking alloc_workqueue(). this patch only kick a worker based on the actual activation of delayed works. Signed-off-by: Yunfeng Ye Reviewed-by: Lai Jiangshan Signed-off-by: Tejun Heo Signed-off-by: Sasha Levin --- diff --git a/kernel/workqueue.c b/kernel/workqueue.c index 18fae55713b0..79fcec674485 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -3494,17 +3494,24 @@ static void pwq_adjust_max_active(struct pool_workqueue *pwq) * is updated and visible. */ if (!freezable || !workqueue_freezing) { + bool kick = false; + pwq->max_active = wq->saved_max_active; while (!list_empty(&pwq->delayed_works) && - pwq->nr_active < pwq->max_active) + pwq->nr_active < pwq->max_active) { pwq_activate_first_delayed(pwq); + kick = true; + } /* * Need to kick a worker after thawed or an unbound wq's - * max_active is bumped. It's a slow path. Do it always. + * max_active is bumped. In realtime scenarios, always kicking a + * worker will cause interference on the isolated cpu cores, so + * let's kick iff work items were activated. */ - wake_up_worker(pwq->pool); + if (kick) + wake_up_worker(pwq->pool); } else { pwq->max_active = 0; }