From: Tejun Heo <tj@kernel.org>
To: Qais Yousef <qais.yousef@arm.com>
Cc: Xuewen Yan <xuewen.yan94@gmail.com>,
Waiman Long <longman@redhat.com>,
Xuewen Yan <xuewen.yan@unisoc.com>,
rafael@kernel.org, viresh.kumar@linaro.org, mingo@redhat.com,
peterz@infradead.org, juri.lelli@redhat.com,
vincent.guittot@linaro.org, dietmar.eggemann@arm.com,
rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de,
bristot@redhat.com, linux-kernel@vger.kernel.org,
ke.wang@unisoc.com, xuewyan@foxmail.com,
linux-pm@vger.kernel.org, Lukasz Luba <Lukasz.Luba@arm.com>,
pengcheng.lai@unisoc.com
Subject: Re: [PATCH] sched/schedutil: Fix deadlock between cpuset and cpu hotplug when using schedutil
Date: Fri, 29 Jul 2022 09:59:17 -1000 [thread overview]
Message-ID: <YuQ8FWtrMsgDmGAr@slm.duckdns.org> (raw)
In-Reply-To: <20220729083949.6uaojl3vqyvwpkuk@wubuntu>
On Fri, Jul 29, 2022 at 09:39:49AM +0100, Qais Yousef wrote:
> I *think* it's because we haven't removed cpus_read_lock() from
> cpuset_attach(). So we end up holding the lock twice in the same path. Since we
> hold it unconditionally now, we should remove cpuset dependency on
> cpus_read_lock() I believe.
Ah, yeah, that's because pending write locker makes future reader lockers
wait, so even if we're holding read lock, if we try to read lock again, we
end up waiting. I'll make the cpus_read_lock() unconditional in cgroup core
and drop it from cpuset's attach operation.
Thanks.
--
tejun
next prev parent reply other threads:[~2022-07-29 19:59 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-05 12:37 [PATCH] sched/schedutil: Fix deadlock between cpuset and cpu hotplug when using schedutil Xuewen Yan
2022-07-11 7:21 ` Xuewen Yan
2022-07-11 7:32 ` Lukasz Luba
2022-07-11 7:43 ` Xuewen Yan
2022-07-11 7:47 ` Viresh Kumar
2022-07-11 7:50 ` Lukasz Luba
2022-07-11 17:46 ` Qais Yousef
2022-07-11 20:58 ` Tejun Heo
2022-07-11 21:11 ` Steven Rostedt
2022-07-12 5:42 ` Xuewen Yan
2022-07-12 5:57 ` Xuewen Yan
2022-07-13 3:02 ` Waiman Long
2022-07-12 12:57 ` Qais Yousef
2022-07-12 16:13 ` Tejun Heo
2022-07-12 17:14 ` Qais Yousef
2022-07-27 22:01 ` Peter Zijlstra
2022-07-27 22:05 ` Tejun Heo
2022-07-13 2:49 ` Waiman Long
2022-07-13 3:00 ` Tejun Heo
2022-07-20 7:45 ` Xuewen Yan
2022-07-27 20:09 ` Tejun Heo
2022-07-29 7:33 ` Xuewen Yan
2022-07-29 8:39 ` Qais Yousef
2022-07-29 19:59 ` Tejun Heo [this message]
2022-08-09 2:02 ` Xuewen Yan
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=YuQ8FWtrMsgDmGAr@slm.duckdns.org \
--to=tj@kernel.org \
--cc=Lukasz.Luba@arm.com \
--cc=bristot@redhat.com \
--cc=bsegall@google.com \
--cc=dietmar.eggemann@arm.com \
--cc=juri.lelli@redhat.com \
--cc=ke.wang@unisoc.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=longman@redhat.com \
--cc=mgorman@suse.de \
--cc=mingo@redhat.com \
--cc=pengcheng.lai@unisoc.com \
--cc=peterz@infradead.org \
--cc=qais.yousef@arm.com \
--cc=rafael@kernel.org \
--cc=rostedt@goodmis.org \
--cc=vincent.guittot@linaro.org \
--cc=viresh.kumar@linaro.org \
--cc=xuewen.yan94@gmail.com \
--cc=xuewen.yan@unisoc.com \
--cc=xuewyan@foxmail.com \
/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).