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authorYunfeng Ye <yeyunfeng@huawei.com>2020-11-19 14:21:25 +0800
committerTejun Heo <tj@kernel.org>2020-11-25 17:10:28 -0500
commit01341fbd0d8d4e717fc1231cdffe00343088ce0b (patch)
treeff3811c2c56f56b94ec7687bf943454112591fda /kernel/workqueue.c
parent127c501a03d5db8b833e953728d3bcf53c8832a9 (diff)
workqueue: Kick a worker based on the actual activation of delayed works
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 <yeyunfeng@huawei.com> Reviewed-by: Lai Jiangshan <jiangshanlai@gmail.com> Signed-off-by: Tejun Heo <tj@kernel.org>
Diffstat (limited to 'kernel/workqueue.c')
-rw-r--r--kernel/workqueue.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/kernel/workqueue.c b/kernel/workqueue.c
index 437935e7a199..0695c7895c89 100644
--- a/kernel/workqueue.c
+++ b/kernel/workqueue.c
@@ -3728,17 +3728,24 @@ 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;
}