From: Johannes Weiner <hannes@cmpxchg.org>
To: Shakeel Butt <shakeelb@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Tejun Heo <tj@kernel.org>, Roman Gushchin <guro@fb.com>,
Michal Hocko <mhocko@suse.com>, Linux MM <linux-mm@kvack.org>,
Cgroups <cgroups@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
Kernel Team <kernel-team@fb.com>
Subject: Re: [PATCH] mm: memcontrol: prevent starvation when writing memory.high
Date: Tue, 12 Jan 2021 14:53:06 -0500 [thread overview]
Message-ID: <X/3+IgDVb+Jn4XfQ@cmpxchg.org> (raw)
In-Reply-To: <CALvZod4VFA52dsdkW79-gUbiCf2ONfFJj6LkRU+3-fQpvYXL+A@mail.gmail.com>
On Tue, Jan 12, 2021 at 10:59:58AM -0800, Shakeel Butt wrote:
> On Tue, Jan 12, 2021 at 9:12 AM Johannes Weiner <hannes@cmpxchg.org> wrote:
> >
> > When a value is written to a cgroup's memory.high control file, the
> > write() context first tries to reclaim the cgroup to size before
> > putting the limit in place for the workload. Concurrent charges from
> > the workload can keep such a write() looping in reclaim indefinitely.
> >
>
> Is this observed on real workload?
Yes.
On several production hosts running a particularly aggressive
workload, we've observed writers to memory.high getting stuck for
minutes while consuming significant amount of CPU.
> Any particular reason to remove !reclaimed?
It's purpose so far was to allow successful reclaim to continue
indefinitely, while restricting no-progress loops to 'nr_retries'.
Without the first part, it doesn't really matter whether reclaim is
making progress or not: we do a maximum of 'nr_retries' loops until
the cgroup size meets the new limit, then exit one way or another.
next prev parent reply other threads:[~2021-01-12 19:55 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-01-12 16:30 Johannes Weiner
2021-01-12 17:03 ` Roman Gushchin
2021-01-12 19:45 ` Johannes Weiner
2021-01-12 20:12 ` Roman Gushchin
2021-01-12 21:11 ` Johannes Weiner
2021-01-12 21:45 ` Roman Gushchin
2021-01-15 15:34 ` Johannes Weiner
2021-01-12 18:59 ` Shakeel Butt
2021-01-12 19:53 ` Johannes Weiner [this message]
2021-01-12 20:28 ` Shakeel Butt
2021-01-13 14:46 ` Michal Hocko
2021-01-15 16:20 ` Johannes Weiner
2021-01-15 17:03 ` Roman Gushchin
2021-01-15 20:55 ` Johannes Weiner
2021-01-15 21:27 ` Roman Gushchin
2021-01-19 16:47 ` Johannes Weiner
2021-01-18 13:12 ` Michal Hocko
2021-01-13 17:25 ` Michal Koutný
2021-01-13 18:06 ` Roman Gushchin
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