From: Oleg Nesterov <oleg@redhat.com>
To: Tejun Heo <tj@kernel.org>
Cc: Roman Gushchin <guro@fb.com>, Roman Gushchin <guroan@gmail.com>,
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 v8 0/7] freezer for cgroup v2
Date: Fri, 22 Feb 2019 17:34:42 +0100 [thread overview]
Message-ID: <20190222163441.GA5596@redhat.com> (raw)
In-Reply-To: <20190221173422.GY50184@devbig004.ftw2.facebook.com>
Hi,
On 02/21, Tejun Heo wrote:
>
> So, I really wanna avoid allowing userspace to cause D state sleeps.
...
> ptrace support is a lot less important than kill for sure but if at
> all possible I think it'd be better to have it
Tejun, I agree it would be better. I did not argue with that.
The question is how this can be implemented. And how much uglifications^W
complications in the core kernel code this needs.
> To summarize, the ideal result is the frozen state to be "stuck in
> jobctl stop loop"
Not sure I understand, but I don't think this can work...
Let me repeat, imo the freezer should be "reliable", it shouldn't stuck
in CGRP_FREEZE state forever if, say, it races with vfork(). And personally
I think this is more important than (very limited) ptrace support.
So I think it too should somehow interact with freezable_schedule/etc.
Oleg.
next prev parent reply other threads:[~2019-02-22 16:34 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-19 22:02 [PATCH v8 0/7] freezer for cgroup v2 Roman Gushchin
2019-02-19 22:02 ` [PATCH v8 1/7] cgroup: rename freezer.c into legacy_freezer.c Roman Gushchin
2019-02-19 22:02 ` [PATCH v8 2/7] cgroup: implement __cgroup_task_count() helper Roman Gushchin
2019-02-19 22:02 ` [PATCH v8 3/7] cgroup: protect cgroup->nr_(dying_)descendants by css_set_lock Roman Gushchin
2019-02-19 22:02 ` [PATCH v8 4/7] cgroup: cgroup v2 freezer Roman Gushchin
2019-02-20 14:42 ` Oleg Nesterov
2019-02-20 22:14 ` Roman Gushchin
2019-02-21 16:44 ` Oleg Nesterov
2019-02-19 22:02 ` [PATCH v8 5/7] kselftests: cgroup: don't fail on cg_kill_all() error in cg_destroy() Roman Gushchin
2019-02-19 22:02 ` Roman Gushchin
2019-02-19 22:02 ` guroan
2019-02-19 22:02 ` [PATCH v8 6/7] kselftests: cgroup: add freezer controller self-tests Roman Gushchin
2019-02-19 22:02 ` Roman Gushchin
2019-02-19 22:02 ` guroan
2019-02-19 22:02 ` [PATCH v8 7/7] cgroup: document cgroup v2 freezer interface Roman Gushchin
2019-02-20 14:37 ` [PATCH v8 0/7] freezer for cgroup v2 Oleg Nesterov
2019-02-20 22:00 ` Roman Gushchin
2019-02-21 16:29 ` Oleg Nesterov
2019-02-21 17:34 ` Tejun Heo
2019-02-22 16:34 ` Oleg Nesterov [this message]
2019-02-22 18:17 ` Tejun Heo
2019-02-25 15:57 ` Oleg Nesterov
2019-03-05 17:27 ` Tejun Heo
2019-02-21 22:43 ` Roman Gushchin
2019-02-22 17:04 ` Oleg Nesterov
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