From: Balbir Singh <bsingharora@gmail.com>
To: Tejun Heo <tj@kernel.org>
Cc: "cgroups@vger.kernel.org" <cgroups@vger.kernel.org>,
Oleg Nesterov <oleg@redhat.com>,
Andrew Morton <akpm@linux-foundation.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>
Subject: Re: [RFC][PATCH] cgroup_threadgroup_rwsem - affects scalability and OOM
Date: Wed, 10 Aug 2016 11:21:17 +1000 [thread overview]
Message-ID: <CAKTCnzkXaZHaJVJGodphFRAnDfDzh9NKTYQqJ-90CMZ93epk3Q@mail.gmail.com> (raw)
In-Reply-To: <20160809142603.GE4906@mtj.duckdns.org>
On Wed, Aug 10, 2016 at 12:26 AM, Tejun Heo <tj@kernel.org> wrote:
> Hello, Balbir.
>
> On Tue, Aug 09, 2016 at 05:02:47PM +1000, Balbir Singh wrote:
>> > Hmm? Where does mem_cgroup_iter grab cgroup_mutex? cgroup_mutex nests
>> > outside cgroup_threadgroup_rwsem or most other mutexes for that matter
>> > and isn't exposed from cgroup core.
>> >
>>
>> I based my theory on the code
>>
>> mem_cgroup_iter -> css_next_descendant_pre which asserts
>>
>> cgroup_assert_mutex_or_rcu_locked(),
>>
>> although you are right, we hold RCU lock while calling css_* routines.
>
> That's "or". The iterator can be called either with RCU lock or
> cgroup_mutex. cgroup core may use it under cgroup_mutex. Everyone
> else uses it with rcu.
>
> Thanks.
>
Hi, Tejun
Thanks agreed! Could you please consider queuing the fix after review.
Balbir Singh.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2016-08-10 1:21 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-09 4:19 [RFC][PATCH] cgroup_threadgroup_rwsem - affects scalability and OOM Balbir Singh
2016-08-09 6:29 ` Tejun Heo
2016-08-09 7:02 ` Balbir Singh
2016-08-09 14:26 ` Tejun Heo
2016-08-10 1:21 ` Balbir Singh [this message]
2016-08-09 9:00 ` Zefan Li
2016-08-09 13:57 ` Balbir Singh
2016-08-10 1:31 ` Zefan Li
2016-08-09 18:09 ` Oleg Nesterov
2016-08-10 19:43 ` Tejun Heo
2016-08-11 23:47 ` Balbir Singh
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=CAKTCnzkXaZHaJVJGodphFRAnDfDzh9NKTYQqJ-90CMZ93epk3Q@mail.gmail.com \
--to=bsingharora@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=cgroups@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=oleg@redhat.com \
--cc=tj@kernel.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;
as well as URLs for NNTP newsgroup(s).