From: Tejun Heo <tj@kernel.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Chengming Zhou <zhouchengming@bytedance.com>,
surenb@google.com, mingo@redhat.com, peterz@infradead.org,
corbet@lwn.net, akpm@linux-foundation.org, rdunlap@infradead.org,
linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
songmuchun@bytedance.com, cgroups@vger.kernel.org
Subject: Re: [PATCH 8/9] sched/psi: add kernel cmdline parameter psi_inner_cgroup
Date: Wed, 3 Aug 2022 09:48:18 -1000 [thread overview]
Message-ID: <YurRAnUEloaYMx0W@slm.duckdns.org> (raw)
In-Reply-To: <YurK6MXdJPrV2VYS@cmpxchg.org>
Hello,
On Wed, Aug 03, 2022 at 03:22:16PM -0400, Johannes Weiner wrote:
> Where it gets trickier is also stopping the tracking of task counts in
> a cgroup. For re-enabling afterwards, we'd have to freeze scheduler
> and cgroup state and find all tasks of interest across all CPUs for
> the given cgroup to recreate the counts. I'm not quite sure whether
> that's feasible, and if so, whether it's worth the savings.
If this turns out to be necessary, I wonder whether we can just be
opportunistic. ie. don't bother with walking all the tasks but only remember
whether a task is accounted at a given level or not (this can be a bitmap
which is allocated at cgroup attach type and in most caess will be pretty
small). Then, maybe we can just start accounting them as they cycle through
state transitions - we ignore the ones leaving states that they weren't
accounted for and start remembering the new states they enter.
Thanks.
--
tejun
next prev parent reply other threads:[~2022-08-03 19:48 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-21 4:04 [PATCH 0/9] sched/psi: some optimization and extension Chengming Zhou
2022-07-21 4:04 ` [PATCH 1/9] sched/psi: fix periodic aggregation shut off Chengming Zhou
2022-07-25 15:34 ` Johannes Weiner
2022-07-25 15:39 ` Johannes Weiner
2022-07-26 13:28 ` Chengming Zhou
2022-07-21 4:04 ` [PATCH 2/9] sched/psi: optimize task switch inside shared cgroups again Chengming Zhou
2022-07-21 4:04 ` [PATCH 3/9] sched/psi: move private helpers to sched/stats.h Chengming Zhou
2022-07-25 16:39 ` Johannes Weiner
2022-07-21 4:04 ` [PATCH 4/9] sched/psi: don't change task psi_flags when migrate CPU/group Chengming Zhou
2022-07-21 4:04 ` [PATCH 5/9] sched/psi: don't create cgroup PSI files when psi_disabled Chengming Zhou
2022-07-25 16:41 ` Johannes Weiner
2022-07-21 4:04 ` [PATCH 6/9] sched/psi: save percpu memory when !psi_cgroups_enabled Chengming Zhou
2022-07-25 16:47 ` Johannes Weiner
2022-07-21 4:04 ` [PATCH 7/9] sched/psi: cache parent psi_group to speed up groups iterate Chengming Zhou
2022-07-21 4:04 ` [PATCH 8/9] sched/psi: add kernel cmdline parameter psi_inner_cgroup Chengming Zhou
2022-07-25 16:52 ` Johannes Weiner
2022-07-26 13:38 ` [External] " Chengming Zhou
2022-07-26 17:54 ` Tejun Heo
2022-08-03 12:17 ` Chengming Zhou
2022-08-03 17:58 ` Tejun Heo
2022-08-03 19:22 ` Johannes Weiner
2022-08-03 19:48 ` Tejun Heo [this message]
2022-08-04 13:51 ` Chengming Zhou
2022-08-04 16:56 ` Johannes Weiner
2022-08-04 2:02 ` Chengming Zhou
2022-07-21 4:04 ` [PATCH 9/9] sched/psi: add PSI_IRQ to track IRQ/SOFTIRQ pressure Chengming Zhou
2022-07-21 10:00 ` kernel test robot
2022-07-21 22:10 ` kernel test robot
2022-07-22 3:30 ` Abel Wu
2022-07-22 6:13 ` Chengming Zhou
2022-07-22 7:14 ` Abel Wu
2022-07-22 7:33 ` Chengming Zhou
2022-07-25 18:26 ` Johannes Weiner
2022-07-26 13:55 ` [External] " Chengming Zhou
2022-07-27 11:28 ` Chengming Zhou
2022-07-27 13:00 ` Johannes Weiner
2022-07-27 15:09 ` Chengming Zhou
2022-07-27 16:07 ` Peter Zijlstra
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