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 17:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-03-20 10:03 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
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