From: Oleg Nesterov <oleg@redhat.com>
To: Roman Gushchin <guro@fb.com>
Cc: Roman Gushchin <guroan@gmail.com>, Tejun Heo <tj@kernel.org>,
Kernel Team <Kernel-team@fb.com>,
"cgroups@vger.kernel.org" <cgroups@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v10 4/9] cgroup: cgroup v2 freezer
Date: Fri, 26 Apr 2019 19:40:19 +0200 [thread overview]
Message-ID: <20190426174019.GB24755@redhat.com> (raw)
In-Reply-To: <20190424220634.GA22896@tower.DHCP.thefacebook.com>
On 04/24, Roman Gushchin wrote:
>
> On Wed, Apr 24, 2019 at 05:46:19PM +0200, Oleg Nesterov wrote:
> >
> > OK, how about the ABSOLUTELY UNTESTED patch below? For the start.
>
> It looks good to me (and all freezer selftests pass).
>
> Just to be sure, is it a solution to avoid the busy loop in the signal handling
> loop, right?
Yes,
> Because it doesn't allow to drop the ->frozen check from recalc().
Yes. Because we can race with unfreeze after leave_frozen().
> The JOBCTL_TRAP_FREEZE check without siglock initially looked dangerous to me,
> but after some thoughts I didn't find any case when it's wrong.
I think this is fine... Yes, JOBCTL_TRAP_FREEZE can be already set when we take
siglock, but I don't think we need to recheck this flag.
The only important thing (afaics) is that CGRP_FREEZE is stable under css_set_lock,
so we can't wrongly set TRAP_FREEZE.
> Do you prefer me to master a patch
Yes please ;)
Oleg.
next prev parent reply other threads:[~2019-04-26 17:40 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-05 17:46 [PATCH v10 0/9] freezer for cgroup v2 Roman Gushchin
2019-04-05 17:47 ` [PATCH v10 1/9] cgroup: rename freezer.c into legacy_freezer.c Roman Gushchin
2019-04-05 17:47 ` [PATCH v10 2/9] cgroup: implement __cgroup_task_count() helper Roman Gushchin
2019-04-05 17:47 ` [PATCH v10 3/9] cgroup: protect cgroup->nr_(dying_)descendants by css_set_lock Roman Gushchin
2019-04-05 17:47 ` [PATCH v10 4/9] cgroup: cgroup v2 freezer Roman Gushchin
2019-04-19 15:19 ` Oleg Nesterov
2019-04-19 16:08 ` Oleg Nesterov
2019-04-19 16:36 ` Roman Gushchin
2019-04-19 16:11 ` Roman Gushchin
2019-04-19 16:26 ` Oleg Nesterov
2019-04-19 16:56 ` Roman Gushchin
2019-04-20 10:58 ` Oleg Nesterov
2019-04-22 22:11 ` Roman Gushchin
2019-04-24 15:46 ` Oleg Nesterov
2019-04-24 22:06 ` Roman Gushchin
2019-04-26 17:40 ` Oleg Nesterov [this message]
2019-04-24 16:02 ` Oleg Nesterov
2019-04-24 22:10 ` Roman Gushchin
2019-04-26 17:30 ` Oleg Nesterov
2019-04-05 17:47 ` [PATCH v10 5/9] kselftests: cgroup: don't fail on cg_kill_all() error in cg_destroy() Roman Gushchin
2019-04-05 17:47 ` Roman Gushchin
2019-04-05 17:47 ` guroan
2019-04-05 17:47 ` [PATCH v10 6/9] kselftests: cgroup: add freezer controller self-tests Roman Gushchin
2019-04-05 17:47 ` Roman Gushchin
2019-04-05 17:47 ` guroan
2019-07-16 14:48 ` Naresh Kamboju
2019-07-17 0:49 ` Roman Gushchin
2019-07-17 8:56 ` Naresh Kamboju
2019-07-18 18:19 ` Roman Gushchin
2019-04-05 17:47 ` [PATCH v10 7/9] cgroup: make TRACE_CGROUP_PATH irq-safe Roman Gushchin
2019-04-05 17:47 ` [PATCH v10 8/9] cgroup: add tracing points for cgroup v2 freezer Roman Gushchin
2019-04-05 17:47 ` [PATCH v10 9/9] cgroup: document cgroup v2 freezer interface Roman Gushchin
2019-04-19 18:29 ` [PATCH v10 0/9] freezer for cgroup v2 Tejun Heo
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