From: Peter Zijlstra <peterz@infradead.org>
To: Patrick Bellasi <patrick.bellasi@arm.com>
Cc: linux-kernel@vger.kernel.org, linux-pm@vger.kernel.org,
Ingo Molnar <mingo@redhat.com>, Tejun Heo <tj@kernel.org>,
"Rafael J . Wysocki" <rafael.j.wysocki@intel.com>,
Viresh Kumar <viresh.kumar@linaro.org>,
Vincent Guittot <vincent.guittot@linaro.org>,
Paul Turner <pjt@google.com>,
Dietmar Eggemann <dietmar.eggemann@arm.com>,
Morten Rasmussen <morten.rasmussen@arm.com>,
Juri Lelli <juri.lelli@redhat.com>,
Joel Fernandes <joelaf@google.com>,
Steve Muckle <smuckle@google.com>
Subject: Re: [PATCH 1/7] sched/core: uclamp: add CPU clamp groups accounting
Date: Fri, 13 Apr 2018 14:44:58 +0200 [thread overview]
Message-ID: <20180413124458.GG4082@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20180413114745.GV14248@e110439-lin>
On Fri, Apr 13, 2018 at 12:47:45PM +0100, Patrick Bellasi wrote:
> In the past I remember some funny dance in cgroup callbacks when a
> task was terminating (like being moved in the root-rq just before
> exiting). But, as you say, if we always have the task_rq_lock we
> should be safe.
The syscall does the whole:
task_rq_lock();
queued = task_on_rq_queued();
running = task_current();
if (queued)
dequeue_task();
if (running)
put_prev_task();
/*
* task is in invariant state here,
* muck with it.
*/
if (queued)
enqueue_task();
if (running)
set_curr_task()
task_rq_unlock();
pattern; which because C sucks, we've not found a good template for yet.
Without the dequeue/put,enqueue/set you have to jump a few extra hoops.
next prev parent reply other threads:[~2018-04-13 12:45 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-04-09 16:56 [PATCH 0/7] Add utilization clamping support Patrick Bellasi
2018-04-09 16:56 ` [PATCH 1/7] sched/core: uclamp: add CPU clamp groups accounting Patrick Bellasi
2018-04-13 8:26 ` Peter Zijlstra
2018-04-13 10:22 ` Peter Zijlstra
2018-04-13 11:04 ` Patrick Bellasi
2018-04-13 11:15 ` Peter Zijlstra
2018-04-13 8:40 ` Peter Zijlstra
2018-04-13 11:17 ` Patrick Bellasi
2018-04-13 11:29 ` Peter Zijlstra
2018-04-13 11:33 ` Patrick Bellasi
2018-04-13 8:43 ` Peter Zijlstra
2018-04-13 11:15 ` Patrick Bellasi
2018-04-13 11:36 ` Peter Zijlstra
2018-04-13 11:47 ` Patrick Bellasi
2018-04-13 11:52 ` Patrick Bellasi
2018-04-13 12:44 ` Peter Zijlstra [this message]
2018-04-13 9:30 ` Peter Zijlstra
2018-04-13 9:38 ` Peter Zijlstra
2018-04-13 9:46 ` Peter Zijlstra
2018-04-13 11:08 ` Patrick Bellasi
2018-04-13 11:19 ` Peter Zijlstra
2018-04-09 16:56 ` [PATCH 2/7] sched/core: uclamp: map TASK clamp values into CPU clamp groups Patrick Bellasi
2018-04-09 16:56 ` [PATCH 3/7] sched/core: uclamp: extend sched_setattr to support utilization clamping Patrick Bellasi
2018-04-09 16:56 ` [PATCH 4/7] sched/core: uclamp: add utilization clamping to the CPU controller Patrick Bellasi
2018-04-09 22:24 ` Tejun Heo
2018-04-10 17:16 ` Patrick Bellasi
2018-04-10 20:05 ` Tejun Heo
2018-04-21 21:08 ` Joel Fernandes
2018-04-26 18:58 ` Tejun Heo
2018-04-09 16:56 ` [PATCH 5/7] sched/core: uclamp: use TG clamps to restrict TASK clamps Patrick Bellasi
2018-04-09 16:56 ` [PATCH 6/7] sched/cpufreq: uclamp: add utilization clamping for FAIR tasks Patrick Bellasi
2018-04-09 16:56 ` [PATCH 7/7] sched/cpufreq: uclamp: add utilization clamping for RT tasks Patrick Bellasi
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180413124458.GG4082@hirez.programming.kicks-ass.net \
--to=peterz@infradead.org \
--cc=dietmar.eggemann@arm.com \
--cc=joelaf@google.com \
--cc=juri.lelli@redhat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=morten.rasmussen@arm.com \
--cc=patrick.bellasi@arm.com \
--cc=pjt@google.com \
--cc=rafael.j.wysocki@intel.com \
--cc=smuckle@google.com \
--cc=tj@kernel.org \
--cc=vincent.guittot@linaro.org \
--cc=viresh.kumar@linaro.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).