From: Johannes Weiner <hannes@cmpxchg.org>
To: Shakeel Butt <shakeelb@google.com>
Cc: Michal Hocko <mhocko@kernel.org>, Roman Gushchin <guro@fb.com>,
Greg Thelen <gthelen@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linux MM <linux-mm@kvack.org>, Cgroups <cgroups@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] memcg: oom: ignore oom warnings from memory.max
Date: Tue, 5 May 2020 12:57:34 -0400 [thread overview]
Message-ID: <20200505165734.GD58018@cmpxchg.org> (raw)
In-Reply-To: <CALvZod5H-fDbvu73=hkzN0Man_+03ZW0d5zc1N0YObVHSiy0Tw@mail.gmail.com>
On Tue, May 05, 2020 at 08:03:17AM -0700, Shakeel Butt wrote:
> On Tue, May 5, 2020 at 12:13 AM Michal Hocko <mhocko@kernel.org> wrote:
> > So instead of potentially removing a useful information can we focus on
> > the remote charging side of the problem and deal with it in a sensible
> > way? That would make memory.high usable for your usecase and I still
> > believe that this is what you should be using in the first place.
>
> We talked about this at LSFMM'19 and I think the decision was to not
> fix high reclaim for remote memcg until it will be an actual issue. I
> suppose now we can treat it as an actual issue.
>
> There are a couple of open questions:
> 1) Should the remote chargers be throttled and do the high reclaim?
I would say it depends on the caller. We may need both: a centralized
charger like a kthread that does work on behalf of many cgroups should
not be throttled, or we risk priority inversions - maybe not even held
up for reclaim, although that would need some thinking about
memory.max as well - whether remote charges should be allowed to
overrun memory.max temporarily, and we punt all reclaim from such
contexts to a worker. (Preferrably, in the future, with all the cpu
cycles of that worker accounted to the cgroup. We want that for
kswapd-style background reclaim as well).
We do similar things with IO for example, when offloading IO to a
central kthread. The kthread is allowed to proceed past a cgroup's
allowance in order to make forward progress, and the cgroup will be
forced to pay up retroactively when it comes back for more of the
resource.
next prev parent reply other threads:[~2020-05-05 16:57 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-04-30 18:27 [PATCH] memcg: oom: ignore oom warnings from memory.max Shakeel Butt
2020-04-30 19:06 ` Roman Gushchin
2020-04-30 19:30 ` Johannes Weiner
2020-04-30 20:23 ` Roman Gushchin
2020-04-30 19:31 ` Shakeel Butt
2020-04-30 19:29 ` Johannes Weiner
2020-04-30 20:20 ` Shakeel Butt
2020-05-04 6:57 ` Michal Hocko
2020-05-04 13:54 ` Shakeel Butt
2020-05-01 1:39 ` Yafang Shao
2020-05-01 2:04 ` Shakeel Butt
2020-05-01 2:12 ` Yafang Shao
2020-05-04 7:03 ` Michal Hocko
2020-05-04 7:26 ` Yafang Shao
2020-05-04 7:35 ` Michal Hocko
2020-05-04 7:40 ` Yafang Shao
2020-05-04 8:03 ` Michal Hocko
2020-05-04 6:56 ` Michal Hocko
2020-05-04 13:54 ` Shakeel Butt
2020-05-04 14:11 ` Michal Hocko
2020-05-04 14:53 ` Shakeel Butt
2020-05-04 15:00 ` Michal Hocko
2020-05-04 15:35 ` Shakeel Butt
2020-05-04 15:39 ` Yafang Shao
2020-05-04 16:06 ` Michal Hocko
2020-05-04 19:23 ` Shakeel Butt
2020-05-05 7:13 ` Michal Hocko
2020-05-05 15:03 ` Shakeel Butt
2020-05-05 16:57 ` Johannes Weiner [this message]
2020-05-05 15:27 ` Johannes Weiner
2020-05-05 15:35 ` Shakeel Butt
2020-05-05 15:49 ` Michal Hocko
2020-05-05 16:40 ` Johannes Weiner
2020-05-04 14:20 ` Tetsuo Handa
2020-05-04 14:57 ` Shakeel Butt
2020-05-04 15:44 ` Tetsuo Handa
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