From: Tejun Heo <tj@kernel.org>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Andrew Morton <akpm@linux-foundation.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>, Chris Mason <clm@fb.com>,
linux-kernel@vger.kernel.org, kernel-team@fb.com,
Li Zefan <lizefan@huawei.com>,
Johannes Weiner <hannes@cmpxchg.org>,
cgroups@vger.kernel.org
Subject: Re: [PATCH 2/2] kthread, cgroup: close race window where new kthreads can be migrated to non-root cgroups
Date: Thu, 16 Mar 2017 13:41:14 -0400 [thread overview]
Message-ID: <20170316174114.GG15810@htj.duckdns.org> (raw)
In-Reply-To: <20170316163158.GB27613@redhat.com>
Hello,
On Thu, Mar 16, 2017 at 05:31:59PM +0100, Oleg Nesterov wrote:
> Or we can add another "unsigned no_cgroups:1" bit into task_struct,
> not sure.
To synchronize around initialization, a PF flag would be easier as we
can use wait_on_bit().
> Anyway, I do not understand the PF_NO_SETAFFINITY check in
> __cgroup_procs_write(). task_can_attach() checks it too, so cgroups
> can't change the affinity. Imo something explicit like no_cgroups
> makes more sense.
task_can_attach() predates the __cgroup_procs_write() and currently
doesn't do anything. We can split the flag or rename it so that it's
more generic. The reasons for disallowing cgroup migration have a lot
of crosssection with affinity, so it's not a complete misnomer.
Either way is fine by me.
Thanks.
--
tejun
next prev parent reply other threads:[~2017-03-16 17:41 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-03-15 23:18 [PATCH 1/2] kthread: add barriers to set_kthread_struct() and to_kthread() Tejun Heo
2017-03-15 23:19 ` [PATCH 2/2] kthread, cgroup: close race window where new kthreads can be migrated to non-root cgroups Tejun Heo
2017-03-16 15:02 ` Oleg Nesterov
2017-03-16 15:39 ` Oleg Nesterov
2017-03-16 16:07 ` Tejun Heo
2017-03-16 16:31 ` Oleg Nesterov
2017-03-16 17:41 ` Tejun Heo [this message]
2017-03-16 16:05 ` Tejun Heo
2017-03-16 16:17 ` Oleg Nesterov
2017-03-16 17:03 ` Tejun Heo
2017-03-16 20:54 ` [PATCH v2] cgroup, kthread: " Tejun Heo
2017-03-17 13:50 ` Oleg Nesterov
2017-03-17 14:44 ` Tejun Heo
2017-03-16 14:54 ` [PATCH 1/2] kthread: add barriers to set_kthread_struct() and to_kthread() Oleg Nesterov
2017-03-16 15:33 ` Tejun Heo
2017-03-16 15:38 ` Tejun Heo
2017-03-16 15:46 ` Oleg Nesterov
2017-03-16 15:55 ` Peter Zijlstra
2017-03-16 16:09 ` Tejun Heo
2017-03-16 16:14 ` Peter Zijlstra
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=20170316174114.GG15810@htj.duckdns.org \
--to=tj@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=cgroups@vger.kernel.org \
--cc=clm@fb.com \
--cc=hannes@cmpxchg.org \
--cc=kernel-team@fb.com \
--cc=linux-kernel@vger.kernel.org \
--cc=lizefan@huawei.com \
--cc=oleg@redhat.com \
--cc=peterz@infradead.org \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.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
all inboxes | Powered by JetHome®