From: Michal Hocko <mhocko@suse.com>
To: Waiman Long <longman@redhat.com>
Cc: Pavel Tikhomirov <ptikhomirov@virtuozzo.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
Shakeel Butt <shakeel.butt@linux.dev>,
Muchun Song <muchun.song@linux.dev>,
Andrew Morton <akpm@linux-foundation.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, kernel@openvz.org
Subject: Re: [PATCH] mm/memcontrol: stop resize loop if limit was changed again
Date: Wed, 20 Mar 2024 18:12:50 +0100 [thread overview]
Message-ID: <ZfsZElNXNf6bOKSt@tiehlicka> (raw)
In-Reply-To: <be05a470-bb31-47ef-b786-557c347de429@redhat.com>
On Wed 20-03-24 13:09:07, Waiman Long wrote:
>
> On 3/20/24 06:03, Pavel Tikhomirov wrote:
> > In memory_max_write() we first set memcg->memory.max and only then
> > try to enforce it in loop. What if while we are in loop someone else
> > have changed memcg->memory.max but we are still trying to enforce
> > the old value? I believe this can lead to nasty consequence like getting
> > an oom on perfectly fine cgroup within it's limits or excess reclaim.
>
> Concurrent write to the same cgroup control file is not possible as the
> underlying kernfs_open_file structure has a mutex that serialize access to
> the file.
This is good to know and I was not aware of that. Thanks!
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2024-03-20 17:12 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-20 10:03 [PATCH] mm/memcontrol: stop resize loop if limit was changed again Pavel Tikhomirov
2024-03-20 10:28 ` Michal Hocko
2024-03-20 10:55 ` Pavel Tikhomirov
2024-03-20 12:09 ` Michal Hocko
2024-03-20 22:38 ` Roman Gushchin
2024-03-20 17:09 ` Waiman Long
2024-03-20 17:12 ` Michal Hocko [this message]
2024-03-20 17:38 ` Michal Hocko
2024-03-21 5:15 ` Pavel Tikhomirov
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=ZfsZElNXNf6bOKSt@tiehlicka \
--to=mhocko@suse.com \
--cc=akpm@linux-foundation.org \
--cc=cgroups@vger.kernel.org \
--cc=hannes@cmpxchg.org \
--cc=kernel@openvz.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=longman@redhat.com \
--cc=muchun.song@linux.dev \
--cc=ptikhomirov@virtuozzo.com \
--cc=roman.gushchin@linux.dev \
--cc=shakeel.butt@linux.dev \
--cc=vdavydov.dev@gmail.com \
/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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.