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From: Tejun Heo <tj@kernel.org>
To: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Cc: linux-rt-devel@lists.linux.dev, cgroups@vger.kernel.org,
	"Johannes Weiner" <hannes@cmpxchg.org>,
	"Michal Koutný" <mkoutny@suse.com>,
	"Clark Williams" <clrkwllms@kernel.org>,
	"Steven Rostedt" <rostedt@goodmis.org>,
	"Bert Karwatzki" <spasswolf@web.de>
Subject: Re: [PATCH] cgroup: Don't expose dead tasks in cgroup
Date: Tue, 3 Mar 2026 07:59:01 -1000	[thread overview]
Message-ID: <aachZbIFl6HCFSxD@slm.duckdns.org> (raw)
In-Reply-To: <20260303131301.ieSSCM4n@linutronix.de>

Hello,

On Tue, Mar 03, 2026 at 02:13:01PM +0100, Sebastian Andrzej Siewior wrote:
...
> I get the same timeout behaviour on !PREEMPT_RT. So it seems like I did
> reduce the race window.

I see.

> So what about doing the removal before sending the signal about the
> upcoming death? Something like:

d245698d727a ("cgroup: Defer task cgroup unlink until after the task is done
switching out") is what created the big wide window causing the regression
and we need that because otherwise the cgroup controllers get confused. I
think we need to figure out where we need to start hiding tasks from listing
to remove the race window and do that explicitly.

Thanks.

-- 
tejun

  reply	other threads:[~2026-03-03 17:59 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-03-02 12:07 [PATCH] cgroup: Don't expose dead tasks in cgroup Sebastian Andrzej Siewior
2026-03-02 21:56 ` Tejun Heo
2026-03-03 13:13   ` Sebastian Andrzej Siewior
2026-03-03 17:59     ` Tejun Heo [this message]
2026-03-03 20:22       ` Tejun Heo
2026-03-04 19:16         ` Sebastian Andrzej Siewior
2026-03-04 19:22           ` Tejun Heo

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