From: Andrew Morton <akpm@linux-foundation.org>
To: Shakeel Butt <shakeelb@google.com>
Cc: Greg Thelen <gthelen@google.com>, Roman Gushchin <guro@fb.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
linux-mm@kvack.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org,
syzbot+13f93c99c06988391efe@syzkaller.appspotmail.com
Subject: Re: [PATCH] mm: vmscan: memcontrol: remove mem_cgroup_select_victim_node()
Date: Tue, 29 Oct 2019 17:54:59 -0700 [thread overview]
Message-ID: <20191029175459.b3bfed9326559e69acdd2e35@linux-foundation.org> (raw)
In-Reply-To: <20191029234753.224143-1-shakeelb@google.com>
On Tue, 29 Oct 2019 16:47:53 -0700 Shakeel Butt <shakeelb@google.com> wrote:
> Since commit 1ba6fc9af35b ("mm: vmscan: do not share cgroup iteration
> between reclaimers"), the memcg reclaim does not bail out earlier based
> on sc->nr_reclaimed and will traverse all the nodes. All the reclaimable
> pages of the memcg on all the nodes will be scanned relative to the
> reclaim priority. So, there is no need to maintain state regarding which
> node to start the memcg reclaim from. Also KCSAN complains data races in
> the code maintaining the state.
>
> This patch effectively reverts the commit 889976dbcb12 ("memcg: reclaim
> memory from nodes in round-robin order") and the commit 453a9bf347f1
> ("memcg: fix numa scan information update to be triggered by memory
> event").
>
> Signed-off-by: Shakeel Butt <shakeelb@google.com>
> Reported-by: <syzbot+13f93c99c06988391efe@syzkaller.appspotmail.com>
I can't find the original sysbot email. Help?
iirc the incidentally-fixed issue is a rather theoretical data race and
the patch isn't a high priority thing?
next prev parent reply other threads:[~2019-10-30 0:55 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-29 23:47 Shakeel Butt
2019-10-29 23:51 ` Roman Gushchin
2019-10-30 0:47 ` Andrew Morton
2019-10-30 0:54 ` Andrew Morton [this message]
2019-10-30 1:15 ` Shakeel Butt
2019-10-30 11:49 ` Michal Hocko
2019-10-30 17:44 ` Johannes Weiner
2019-10-30 17:53 ` Michal Hocko
2019-10-30 18:06 ` Johannes Weiner
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