From: Oleg Nesterov <oleg@redhat.com>
To: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Michal Hocko <mhocko@suse.com>,
Suren Baghdasaryan <surenb@google.com>,
christian.brauner@ubuntu.com, mingo@kernel.org,
peterz@infradead.org, tglx@linutronix.de, esyr@redhat.com,
christian@kellner.me, areber@redhat.com, shakeelb@google.com,
cyphar@cyphar.com, adobriyan@gmail.com,
akpm@linux-foundation.org, gladkov.alexey@gmail.com,
walken@google.com, daniel.m.jordan@oracle.com, avagin@gmail.com,
bernd.edlinger@hotmail.de, john.johansen@canonical.com,
laoar.shao@gmail.com, timmurray@google.com, minchan@kernel.org,
kernel-team@android.com, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 1/1] mm, oom_adj: don't loop through tasks in __set_oom_adj when not necessary
Date: Thu, 20 Aug 2020 16:04:52 +0200 [thread overview]
Message-ID: <20200820140451.GC4546@redhat.com> (raw)
In-Reply-To: <874koxxwn5.fsf@x220.int.ebiederm.org>
On 08/20, Eric W. Biederman wrote:
>
> --- a/fs/exec.c
> +++ b/fs/exec.c
> @@ -1139,6 +1139,10 @@ static int exec_mmap(struct mm_struct *mm)
> vmacache_flush(tsk);
> task_unlock(tsk);
> if (old_mm) {
> + mm->oom_score_adj = old_mm->oom_score_adj;
> + mm->oom_score_adj_min = old_mm->oom_score_adj_min;
> + if (tsk->vfork_done)
> + mm->oom_score_adj = tsk->vfork_oom_score_adj;
too late, ->vfork_done is NULL after mm_release().
And this can race with __set_oom_adj(). Yes, the current code is racy too,
but this change adds another race, __set_oom_adj() could already observe
->mm != NULL and update mm->oom_score_adj.
Oleg.
next prev parent reply other threads:[~2020-08-20 14:05 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-20 0:20 Suren Baghdasaryan
2020-08-20 5:56 ` Michal Hocko
2020-08-20 8:46 ` Christian Brauner
2020-08-20 9:09 ` Michal Hocko
2020-08-20 10:32 ` Christian Brauner
2020-08-20 11:14 ` Michal Hocko
2020-08-20 10:55 ` Oleg Nesterov
2020-08-20 11:13 ` Michal Hocko
2020-08-20 11:29 ` Michal Hocko
2020-08-20 11:41 ` Oleg Nesterov
2020-08-20 11:47 ` Christian Brauner
2020-08-20 11:30 ` Christian Brauner
2020-08-20 11:42 ` Michal Hocko
2020-08-20 12:41 ` Michal Hocko
2020-08-20 13:43 ` Christian Brauner
2020-08-20 12:34 ` Eric W. Biederman
2020-08-20 12:42 ` Michal Hocko
2020-08-20 12:45 ` Eric W. Biederman
2020-08-20 12:54 ` Eric W. Biederman
2020-08-20 13:26 ` Michal Hocko
2020-08-20 13:34 ` Christian Brauner
[not found] ` <dcb62b67-5ad6-f63a-a909-e2fa70b240fc@i-love.sakura.ne.jp>
2020-08-20 14:00 ` Christian Brauner
2020-08-20 14:15 ` Michal Hocko
[not found] ` <42d5645e-0364-c8cd-01dc-93a9aaff5b09@i-love.sakura.ne.jp>
2020-08-20 14:34 ` Michal Hocko
[not found] ` <637ab0e7-e686-0c94-753b-b97d24bb8232@i-love.sakura.ne.jp>
2020-08-20 14:49 ` Eric W. Biederman
2020-08-20 15:06 ` Christian Brauner
2020-08-20 15:56 ` Suren Baghdasaryan
2020-08-20 16:26 ` Michal Hocko
2020-08-20 16:29 ` Christian Brauner
2020-08-20 16:47 ` Suren Baghdasaryan
2020-08-21 4:39 ` Eric W. Biederman
2020-08-21 7:17 ` Michal Hocko
2020-08-21 11:15 ` Oleg Nesterov
2020-08-21 15:28 ` Suren Baghdasaryan
2020-08-21 16:06 ` Suren Baghdasaryan
2020-08-21 16:37 ` Oleg Nesterov
2020-08-21 17:22 ` Suren Baghdasaryan
2020-08-21 16:33 ` Oleg Nesterov
2020-08-21 17:59 ` Oleg Nesterov
2020-08-21 18:53 ` Suren Baghdasaryan
2020-08-24 20:03 ` Suren Baghdasaryan
2020-08-20 13:41 ` Eric W. Biederman
2020-08-20 14:04 ` Oleg Nesterov [this message]
2020-08-20 14:36 ` Oleg Nesterov
2020-08-20 15:06 ` Eric W. Biederman
2020-08-20 14:43 ` Eric W. Biederman
2020-08-20 14:12 ` Michal Hocko
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