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authorJuri Lelli <juri.lelli@redhat.com>2023-05-08 09:58:52 +0200
committerTejun Heo <tj@kernel.org>2023-05-08 13:22:33 -1000
commitc0f78fd5edcf29b2822ac165f9248a6c165e8554 (patch)
treed762a1991f8ea08d021c703d0642830988077fff /kernel/cgroup/cpuset.c
parent6c24849f5515e4966d94fa5279bdff4acf2e9489 (diff)
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 <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>
Diffstat (limited to 'kernel/cgroup/cpuset.c')
-rw-r--r--kernel/cgroup/cpuset.c3
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index ca195ff8b298..b7168970fff2 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)))