From: Juri Lelli Date: Mon, 8 May 2023 07:58:52 +0000 (+0200) Subject: cgroup/cpuset: Iterate only if DEADLINE tasks are present X-Git-Tag: v6.5-rc1~187^2~15 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c0f78fd5edcf29b2822ac165f9248a6c165e8554;p=thirdparty%2Flinux.git cgroup/cpuset: Iterate only if DEADLINE tasks are present update_tasks_root_domain currently iterates over all tasks even if no DEADLINE task is present on the cpuset/root domain for which bandwidth accounting is being rebuilt. This has been reported to introduce 10+ ms delays on suspend-resume operations. Skip the costly iteration for cpusets that don't contain DEADLINE tasks. Reported-by: Qais Yousef Link: https://lore.kernel.org/lkml/20230206221428.2125324-1-qyousef@layalina.io/ Signed-off-by: Juri Lelli Reviewed-by: Waiman Long Signed-off-by: Tejun Heo --- diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index ca195ff8b298b..b7168970fff2e 100644 --- a/kernel/cgroup/cpuset.c +++ b/kernel/cgroup/cpuset.c @@ -1092,6 +1092,9 @@ static void dl_update_tasks_root_domain(struct cpuset *cs) struct css_task_iter it; struct task_struct *task; + if (cs->nr_deadline_tasks == 0) + return; + css_task_iter_start(&cs->css, 0, &it); while ((task = css_task_iter_next(&it)))