From: Michal Hocko <mhocko@suse.com>
To: Alex Shi <alex.shi@linux.alibaba.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Andrew Morton <akpm@linux-foundation.org>,
cgroups@vger.kernel.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm/memcg: remove useless check on page->mem_cgroup
Date: Mon, 10 Aug 2020 11:53:10 +0200 [thread overview]
Message-ID: <20200810095310.GD4773@dhcp22.suse.cz> (raw)
In-Reply-To: <20200810095201.GC4773@dhcp22.suse.cz>
On Mon 10-08-20 11:52:02, Michal Hocko wrote:
> On Wed 05-08-20 21:02:30, Alex Shi wrote:
> >
> >
> > 在 2020/8/5 下午8:28, Alex Shi 写道:
> > > The last patch has a problem on define. this version could fix it.
> > >
> > > BTW, I see some !memcg happens when MEMCG compilered but disabled by cgroup_disable
> > >
> > >
> > > [ 94.657666] ---[ end trace f1f34bfc3b32ed2f ]---
> > > [ 95.138995] anon flags: 0x5005b48008000d(locked|uptodate|dirty|swapbacked)
> > > [ 95.146220] raw: 005005b48008000d dead000000000100 dead000000000122 ffff8897c7c76ad1
> > > [ 95.154549] raw: 0000000000000022 0000000000000000 0000000200000000 0000000000000000
> > > [ 95.162876] page dumped because: VM_WARN_ON_ONCE_PAGE(!memcg)
> > >
> > >
> >
> > The following patch may helpful.
> >
> > >From 8bfb26a2e37e08dc61d20212bcfa5812a367ba94 Mon Sep 17 00:00:00 2001
> > From: Alex Shi <alex.shi@linux.alibaba.com>
> > Date: Wed, 5 Aug 2020 20:32:12 +0800
> > Subject: [PATCH] mm/memcg: don't try charge swap if memcg disabled
> >
> > If we disabled memcg by cgroup_disable=memory, the swap charges are
> > still called. Let's return from the funcs earlier and keep WARN_ON
> > monitor.
>
> Do I get it right that this is on top of your patch to remove the memcg
> check or a preparatory work?
Sorry meant to say - add the warning rather than drop the check.
> Both are good but it would be better to
> call that out specifically for clarity (along with the warning if that
> is a follow up fix).
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2020-08-10 9:53 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-31 3:34 [PATCH] mm/memcg: remove useless check on page->mem_cgroup Alex Shi
2020-07-31 15:16 ` Johannes Weiner
2020-08-01 3:58 ` Alex Shi
2020-08-03 8:18 ` Michal Hocko
2020-08-04 7:35 ` Alex Shi
[not found] ` <92dd8e68-8095-72c5-0144-2a084e4d5993@linux.alibaba.com>
2020-08-05 13:02 ` Alex Shi
2020-08-08 13:22 ` Alex Shi
2020-08-08 21:43 ` Roman Gushchin
2020-08-10 7:44 ` Alex Shi
2020-08-10 9:52 ` Michal Hocko
2020-08-10 9:53 ` Michal Hocko [this message]
2020-08-10 9:55 ` Michal Hocko
2020-08-10 12:29 ` Alex Shi
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