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From: "Bruno Prémont" <bonbons@linux-vserver.org>
To: Michal Hocko <mhocko@kernel.org>
Cc: Chris Down <chris@chrisdown.name>,
	cgroups@vger.kernel.org, linux-mm@kvack.org,
	Johannes Weiner <hannes@cmpxchg.org>,
	Vladimir Davydov <vdavydov.dev@gmail.com>
Subject: Re: Memory CG and 5.1 to 5.6 uprade slows backup
Date: Wed, 15 Apr 2020 13:37:28 +0200	[thread overview]
Message-ID: <20200415133728.3f58d46e@hemera.lan.sysophe.eu> (raw)
In-Reply-To: <20200415102442.GE4629@dhcp22.suse.cz>

On Wed, 15 Apr 2020 12:24:42 Michal Hocko <mhocko@kernel.org> wrote:
> On Wed 15-04-20 12:17:53, Bruno Prémont wrote:
> [...]
> > > Anyway the following simply tracing patch should give a better clue.
> > > The output will appear in the trace buffer (mount tracefs and read
> > > trace_pipe file).  
> > 
> > This is the output I get on 5.6.4 with simple tar -zc call (max=high+4096):
> >   tar-16943 [000] ....  1098.796955: mem_cgroup_handle_over_high: memcg_nr_pages_over_high:1 penalty_jiffies:200 current:262122 high:262144
> >   tar-16943 [000] ....  1100.876794: mem_cgroup_handle_over_high: memcg_nr_pages_over_high:1 penalty_jiffies:200 current:262122 high:262144
> >   tar-16943 [000] ....  1102.956636: mem_cgroup_handle_over_high: memcg_nr_pages_over_high:1 penalty_jiffies:200 current:262120 high:262144
> >   tar-16943 [000] ....  1105.037388: mem_cgroup_handle_over_high: memcg_nr_pages_over_high:1 penalty_jiffies:200 current:262121 high:262144
> >   tar-16943 [000] ....  1107.117246: mem_cgroup_handle_over_high: memcg_nr_pages_over_high:1 penalty_jiffies:200 current:262122 high:262144  
> 
> OK, that points to the underflow fix.
> 
> > 
> > With 5.7-rc1 it runs just fine, pressure remains zero and no output in trace_pipe or throttling.
> > 
> > So the fixes that went in there do fix it.
> > Now matter of cherry-picking the right ones... e26733e0d0ec and its fixe's fix,
> > maybe some others (will start with those tagged for stable).  
> 
> I have seen Greg picking up this for stable trees so it should show up
> there soon.

Applying just 9b8b17541f13809d06f6f873325305ddbb760e3e which went to
stable-rc for 5.6.5 gets things running fine where.
(e26733e0d0ec seems to have gone in shortly prior to 5.6 release, need
to improve my git-foo to locate commits between tags!)

So yes it's the fix.

Thanks,
Bruno

> Thanks!


  reply	other threads:[~2020-04-15 11:37 UTC|newest]

Thread overview: 18+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-09  9:25 Memory CG and 5.1 to 5.6 uprade slows backup Bruno Prémont
2020-04-09  9:46 ` Michal Hocko
2020-04-09 10:17   ` Bruno Prémont
2020-04-09 10:34     ` Michal Hocko
2020-04-09 15:09       ` Bruno Prémont
2020-04-09 15:24         ` Chris Down
2020-04-09 15:40           ` Bruno Prémont
2020-04-09 17:50             ` Chris Down
2020-04-09 17:56               ` Chris Down
2020-04-09 15:25         ` Michal Hocko
2020-04-10  7:15           ` Bruno Prémont
2020-04-10  8:43             ` Bruno Prémont
     [not found]               ` <20200410115010.1d9f6a3f@hemera.lan.sysophe.eu>
     [not found]                 ` <20200414163134.GQ4629@dhcp22.suse.cz>
2020-04-15 10:17                   ` Bruno Prémont
2020-04-15 10:24                     ` Michal Hocko
2020-04-15 11:37                       ` Bruno Prémont [this message]
2020-04-14 15:09           ` Bruno Prémont
2020-04-09 10:50 ` Chris Down
2020-04-09 11:58   ` Bruno Prémont

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