From: Waiman Long <longman@redhat.com>
To: Juri Lelli <juri.lelli@redhat.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@kernel.org>, Qais Yousef <qyousef@layalina.io>,
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>
Subject: Re: [PATCH v2 4/6] cgroup/cpuset: Iterate only if DEADLINE tasks are present
Date: Wed, 3 May 2023 13:56:34 -0400 [thread overview]
Message-ID: <86854aad-d649-9369-c53d-75446ab8de7b@redhat.com> (raw)
In-Reply-To: <20230503072228.115707-5-juri.lelli@redhat.com>
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@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)))
Reviewed-by: Waiman Long <longman@redhat.com>
next prev parent reply other threads:[~2023-05-03 17:57 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 ` [PATCH v2 4/6] cgroup/cpuset: Iterate only if DEADLINE tasks are present Juri Lelli
2023-05-03 17:56 ` Waiman Long [this message]
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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