linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Michal Hocko <mhocko@kernel.org>
To: Cong Wang <xiyou.wangcong@gmail.com>
Cc: 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: Mon, 27 Jan 2020 15:49:31 +0100	[thread overview]
Message-ID: <20200127144931.GM1183@dhcp22.suse.cz> (raw)
In-Reply-To: <CAM_iQpU0p7JLyQ4mQ==Kd7+0ugmricsEAp1ST2ShAZar2BLAWg@mail.gmail.com>

On Sun 26-01-20 11:53:55, Cong Wang wrote:
> On Tue, Jan 21, 2020 at 1:00 AM Michal Hocko <mhocko@kernel.org> wrote:
> >
> > On Mon 20-01-20 14:48:05, Cong Wang wrote:
> > > It got stuck somewhere along the call path of mem_cgroup_try_charge(),
> > > and the trace events of mm_vmscan_lru_shrink_inactive() indicates this
> > > too:
> >
> > So it seems that you are condending on the page lock. It is really
> > unexpected that the reclaim would take that long though. Please try to
> > enable more vmscan tracepoints to see where the time is spent.
> 
> Sorry for the delay. I have been trying to collect more data in one shot.
> 
> This is a a typical round of the loop after enabling all vmscan tracepoints:
> 
>            <...>-455450 [007] .... 4048595.842992:
> mm_vmscan_memcg_reclaim_begin: order=0 may_writepage=1
> gfp_flags=GFP_NOFS|__GFP_HIGHMEM|__GFP_HARDWALL|__GFP_MOVABLE
> classzone_idx=4
>            <...>-455450 [007] .... 4048595.843012:
> mm_vmscan_memcg_reclaim_end: nr_reclaimed=0

This doesn't tell us much though. This reclaim round has taken close to
no time. See timestamps.

> The whole trace output is huge (33M), I can provide it on request.

Focus on reclaim rounds that take a long time and see where it gets you.
-- 
Michal Hocko
SUSE Labs

  parent reply	other threads:[~2020-01-27 14:49 UTC|newest]

Thread overview: 32+ 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
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 [this message]
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
     [not found]   ` <20200121082624.12608-1-hdanton@sina.com>
2020-01-21  9:06     ` Michal Hocko

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20200127144931.GM1183@dhcp22.suse.cz \
    --to=mhocko@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mgorman@suse.de \
    --cc=vbabka@suse.cz \
    --cc=xiyou.wangcong@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).