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| author | Juri Lelli <juri.lelli@redhat.com> | 2023-08-20 16:24:15 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-08-30 16:11:11 +0200 |
| commit | 064b960dbe942114a397788a57474c40cea04185 (patch) | |
| tree | 37d6dc31872f4cd723320f867504a919d7d68d12 | |
| parent | d1b4262b78cc7638642833252ae92fc586854ffb (diff) | |
| download | linux-stable-064b960dbe942114a397788a57474c40cea04185.tar.gz linux-stable-064b960dbe942114a397788a57474c40cea04185.tar.bz2 linux-stable-064b960dbe942114a397788a57474c40cea04185.zip | |
cgroup/cpuset: Iterate only if DEADLINE tasks are present
commit c0f78fd5edcf29b2822ac165f9248a6c165e8554 upstream.
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 (Google) <qyousef@layalina.io>
Link: https://lore.kernel.org/lkml/20230206221428.2125324-1-qyousef@layalina.io/
Signed-off-by: Juri Lelli <juri.lelli@redhat.com>
Reviewed-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Qais Yousef (Google) <qyousef@layalina.io>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | kernel/cgroup/cpuset.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c index 5f57829bb986..eca07ff71656 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))) |