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From: Cong Wang <xiyou.wangcong@gmail.com>
To: Michal Hocko <mhocko@kernel.org>
Cc: Matthew Wilcox <willy@infradead.org>,
	LKML <linux-kernel@vger.kernel.org>,
	 Andrew Morton <akpm@linux-foundation.org>,
	linux-mm <linux-mm@kvack.org>,  Mel Gorman <mgorman@suse.de>,
	Vlastimil Babka <vbabka@suse.cz>
Subject: Re: [PATCH] mm: avoid blocking lock_page() in kcompactd
Date: Thu, 30 Jan 2020 14:52:13 -0800	[thread overview]
Message-ID: <CAM_iQpX2P_NWeR_FTZOcL96Gd0TwDLZY1=X_AeUpYuX=pPE-ew@mail.gmail.com> (raw)
In-Reply-To: <CAM_iQpVjiui0xb7wTfF2HOME=cuk7M2SCBa7O_RVebk04qMs4w@mail.gmail.com>

On Tue, Jan 28, 2020 at 11:44 AM Cong Wang <xiyou.wangcong@gmail.com> wrote:
>
> On Tue, Jan 28, 2020 at 3:39 AM Michal Hocko <mhocko@kernel.org> wrote:
> >
> > On Tue 28-01-20 02:48:57, Matthew Wilcox wrote:
> > > Doesn't the stack trace above indicate that we're doing migration as
> > > the result of an allocation in add_to_page_cache_lru()?
> >
> > Which stack trace do you refer to? Because the one above doesn't show
> > much more beyond mem_cgroup_iter and likewise others in this email
> > thread. I do not really remember any stack with lock_page on the trace.
>
> I think the page is locked in add_to_page_cache_lru() by
> __SetPageLocked(), as the stack trace shows __add_to_page_cache_locked().
> It is not yet unlocked, as it is still looping inside try_charge().
>
> I will write a script to see if I can find the longest time spent in reclaim
> as you suggested.

After digging the changelog, I believe the following commit could fix
the problem:

commit f9c645621a28e37813a1de96d9cbd89cde94a1e4
Author: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Date:   Mon Sep 23 15:37:08 2019 -0700

    memcg, oom: don't require __GFP_FS when invoking memcg OOM killer

which is not yet in our 4.19 branch yet. We will sync with 4.19 stable soon.

Thanks.


  reply	other threads:[~2020-01-30 22:52 UTC|newest]

Thread overview: 33+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-09 22:56 [PATCH] mm: avoid blocking lock_page() in kcompactd Cong Wang
2020-01-10  0:28 ` Yang Shi
2020-01-10  1:01   ` Cong Wang
2020-01-10  4:51     ` Cong Wang
2020-01-10  7:38 ` Michal Hocko
2020-01-20 22:48   ` Cong Wang
2020-01-21  9:00     ` Michal Hocko
2020-01-26 19:53       ` Cong Wang
2020-01-26 23:39         ` Matthew Wilcox
2020-01-27 15:00           ` Michal Hocko
2020-01-27 19:06             ` Matthew Wilcox
2020-01-28  1:25               ` Yang Shi
2020-01-28  6:03                 ` Matthew Wilcox
2020-01-28  8:17               ` Michal Hocko
2020-01-28  8:30                 ` Matthew Wilcox
2020-01-28  9:13                   ` Michal Hocko
2020-01-28 10:48                     ` Matthew Wilcox
2020-01-28 11:39                       ` Michal Hocko
2020-01-28 19:44                         ` Cong Wang
2020-01-30 22:52                           ` Cong Wang [this message]
2020-02-13  7:48                         ` Michal Hocko
2020-02-13 16:46                           ` Matthew Wilcox
2020-02-13 17:08                             ` Michal Hocko
2020-02-14  4:27                               ` Matthew Wilcox
2020-02-14  6:55                                 ` Michal Hocko
2020-01-27 14:49         ` Michal Hocko
2020-01-28  0:46           ` Cong Wang
2020-01-28  8:22             ` Michal Hocko
2020-01-10  9:22 ` Mel Gorman
2020-01-20 22:41   ` Cong Wang
2020-01-21 19:21     ` Yang Shi
2020-01-21  8:26   ` Hillf Danton
2020-01-21  9:06     ` Michal Hocko

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