On 5/3/23 03:22, Juri Lelli wrote:
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@xxxxxxxxxxx>
Link: https://lore.kernel.org/lkml/20230206221428.2125324-1-qyousef@xxxxxxxxxxx/
Signed-off-by: Juri Lelli <juri.lelli@xxxxxxxxxx>
---
kernel/cgroup/cpuset.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/kernel/cgroup/cpuset.c b/kernel/cgroup/cpuset.c
index b9f4d5602517..6587df42cb61 100644
--- a/kernel/cgroup/cpuset.c
+++ b/kernel/cgroup/cpuset.c
@@ -1090,6 +1090,9 @@ 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)))
Reviewed-by: Waiman Long <longman@xxxxxxxxxx>
