From: Oleg Nesterov <oleg@redhat.com>
To: Suren Baghdasaryan <surenb@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>,
Michal Hocko <mhocko@suse.com>,
Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>,
Christian Brauner <christian.brauner@ubuntu.com>,
Tim Murray <timmurray@google.com>,
mingo@kernel.org, Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
esyr@redhat.com, christian@kellner.me, areber@redhat.com,
Shakeel Butt <shakeelb@google.com>,
cyphar@cyphar.com, adobriyan@gmail.com,
Andrew Morton <akpm@linux-foundation.org>,
gladkov.alexey@gmail.com, Michel Lespinasse <walken@google.com>,
daniel.m.jordan@oracle.com, avagin@gmail.com,
bernd.edlinger@hotmail.de,
John Johansen <john.johansen@canonical.com>,
laoar.shao@gmail.com, Minchan Kim <minchan@kernel.org>,
kernel-team <kernel-team@android.com>,
LKML <linux-kernel@vger.kernel.org>,
linux-fsdevel@vger.kernel.org, linux-mm <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: Fri, 21 Aug 2020 18:37:25 +0200 [thread overview]
Message-ID: <20200821163724.GC19445@redhat.com> (raw)
In-Reply-To: <CAJuCfpG06_KLhQyg9N84bRQOdvG27uAZ2oBDEQPR-OnZeNJd1w@mail.gmail.com>
again, don't really understand...
On 08/21, Suren Baghdasaryan wrote:
>
> Actually, reviewing again and considering where list_add_tail_rcu is
> happening, maybe the race with clone(CLONE_VM) does not introduce
> false negatives.
I think it does... Whatever we check, mm_users or MMF_PROC_SHARED,
the task can do clone(CLONE_VM) right after the check.
> However a false negative I think will happen when a
> task shares mm with another task and also has an additional thread.
> Shared mm will increment mm_users without adding to signal->live
Yes,
> and
> the additional thread will advance signal->live without adding to
> mm_users.
No, please note that CLONE_THREAD requires CLONE_VM.
Oleg.
next prev parent reply other threads:[~2020-08-21 16:38 UTC|newest]
Thread overview: 50+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-20 0:20 [PATCH 1/1] mm, oom_adj: don't loop through tasks in __set_oom_adj when not necessary 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
2020-08-20 13:48 ` Tetsuo Handa
2020-08-20 14:00 ` Christian Brauner
2020-08-20 14:15 ` Michal Hocko
2020-08-20 14:26 ` Tetsuo Handa
2020-08-20 14:34 ` Michal Hocko
2020-08-20 14:18 ` Tetsuo Handa
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 [this message]
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
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
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=20200821163724.GC19445@redhat.com \
--to=oleg@redhat.com \
--cc=adobriyan@gmail.com \
--cc=akpm@linux-foundation.org \
--cc=areber@redhat.com \
--cc=avagin@gmail.com \
--cc=bernd.edlinger@hotmail.de \
--cc=christian.brauner@ubuntu.com \
--cc=christian@kellner.me \
--cc=cyphar@cyphar.com \
--cc=daniel.m.jordan@oracle.com \
--cc=ebiederm@xmission.com \
--cc=esyr@redhat.com \
--cc=gladkov.alexey@gmail.com \
--cc=john.johansen@canonical.com \
--cc=kernel-team@android.com \
--cc=laoar.shao@gmail.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@suse.com \
--cc=minchan@kernel.org \
--cc=mingo@kernel.org \
--cc=penguin-kernel@i-love.sakura.ne.jp \
--cc=peterz@infradead.org \
--cc=shakeelb@google.com \
--cc=surenb@google.com \
--cc=tglx@linutronix.de \
--cc=timmurray@google.com \
--cc=walken@google.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.