From: Juri Lelli <juri.lelli@redhat.com>
To: Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>, Qais Yousef <qyousef@layalina.io>,
Waiman Long <longman@redhat.com>, Tejun Heo <tj@kernel.org>,
Zefan Li <lizefan.x@bytedance.com>,
Johannes Weiner <hannes@cmpxchg.org>, Hao Luo <haoluo@google.com>
Cc: Dietmar Eggemann <dietmar.eggemann@arm.com>,
Steven Rostedt <rostedt@goodmis.org>,
linux-kernel@vger.kernel.org, luca.abeni@santannapisa.it,
claudio@evidence.eu.com, tommaso.cucinotta@santannapisa.it,
bristot@redhat.com, mathieu.poirier@linaro.org,
cgroups@vger.kernel.org,
Vincent Guittot <vincent.guittot@linaro.org>,
Wei Wang <wvw@google.com>, Rick Yiu <rickyiu@google.com>,
Quentin Perret <qperret@google.com>,
Heiko Carstens <hca@linux.ibm.com>,
Vasily Gorbik <gor@linux.ibm.com>,
Alexander Gordeev <agordeev@linux.ibm.com>,
Sudeep Holla <sudeep.holla@arm.com>,
Juri Lelli <juri.lelli@redhat.com>
Subject: [PATCH v2 4/6] cgroup/cpuset: Iterate only if DEADLINE tasks are present
Date: Wed, 3 May 2023 09:22:26 +0200 [thread overview]
Message-ID: <20230503072228.115707-5-juri.lelli@redhat.com> (raw)
In-Reply-To: <20230503072228.115707-1-juri.lelli@redhat.com>
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>
---
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)))
--
2.40.1
next prev parent reply other threads:[~2023-05-03 7:24 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-05-03 7:22 [PATCH v2 0/6] sched/deadline: cpuset: Rework DEADLINE bandwidth restoration Juri Lelli
2023-05-03 7:22 ` [PATCH v2 1/6] cgroup/cpuset: Rename functions dealing with DEADLINE accounting Juri Lelli
2023-05-03 17:54 ` Waiman Long
2023-05-03 7:22 ` [PATCH v2 2/6] sched/cpuset: Bring back cpuset_mutex Juri Lelli
2023-05-03 17:55 ` Waiman Long
2023-05-04 6:18 ` Peter Zijlstra
2023-05-04 8:13 ` Juri Lelli
2023-05-04 6:21 ` Peter Zijlstra
2023-05-04 8:13 ` Juri Lelli
2023-05-03 7:22 ` [PATCH v2 3/6] sched/cpuset: Keep track of SCHED_DEADLINE task in cpusets Juri Lelli
2023-05-03 17:56 ` Waiman Long
2023-05-03 7:22 ` Juri Lelli [this message]
2023-05-03 17:56 ` [PATCH v2 4/6] cgroup/cpuset: Iterate only if DEADLINE tasks are present Waiman Long
2023-05-03 7:22 ` [PATCH v2 5/6] sched/deadline: Create DL BW alloc, free & check overflow interface Juri Lelli
2023-05-03 17:45 ` Waiman Long
2023-05-04 6:23 ` Peter Zijlstra
2023-05-04 8:15 ` Juri Lelli
2023-05-04 17:21 ` Dietmar Eggemann
2023-05-03 7:22 ` [PATCH v2 6/6] cgroup/cpuset: Free DL BW in case can_attach() fails Juri Lelli
2023-05-03 18:02 ` Waiman Long
2023-05-04 6:25 ` [PATCH v2 0/6] sched/deadline: cpuset: Rework DEADLINE bandwidth restoration Peter Zijlstra
2023-05-04 8:17 ` Juri Lelli
2023-05-05 19:31 ` Tejun Heo
2023-05-08 8:02 ` Juri Lelli
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