From: Michal Hocko <mhocko@kernel.org>
To: Gerhard Wiesinger <lists@wiesinger.com>
Cc: lkml@pengaru.com, Minchan Kim <minchan@kernel.org>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: Still OOM problems with 4.9er/4.10er kernels
Date: Fri, 17 Mar 2017 18:13:40 +0100 [thread overview]
Message-ID: <20170317171339.GA23957@dhcp22.suse.cz> (raw)
In-Reply-To: <a65e4b73-5c97-d915-c79e-7df0771db823@wiesinger.com>
On Fri 17-03-17 17:37:48, Gerhard Wiesinger wrote:
[...]
> Why does the kernel prefer to swapin/out and not use
>
> a.) the free memory?
It will use all the free memory up to min watermark which is set up
based on min_free_kbytes.
> b.) the buffer/cache?
the memory reclaim is strongly biased towards page cache and we try to
avoid swapout as much as possible (see get_scan_count).
> There is ~100M memory available but kernel swaps all the time ...
>
> Any ideas?
>
> Kernel: 4.9.14-200.fc25.x86_64
>
> top - 17:33:43 up 28 min, 3 users, load average: 3.58, 1.67, 0.89
> Tasks: 145 total, 4 running, 141 sleeping, 0 stopped, 0 zombie
> %Cpu(s): 19.1 us, 56.2 sy, 0.0 ni, 4.3 id, 13.4 wa, 2.0 hi, 0.3 si, 4.7
> st
> KiB Mem : 230076 total, 61508 free, 123472 used, 45096 buff/cache
>
> procs -----------memory---------- ---swap-- -----io---- -system--
> ------cpu-----
> r b swpd free buff cache si so bi bo in cs us sy id wa st
> 3 5 303916 60372 328 43864 27828 200 41420 236 6984 11138 11 47 6 23 14
I am really surprised to see any reclaim at all. 26% of free memory
doesn't sound as if we should do a reclaim at all. Do you have an
unusual configuration of /proc/sys/vm/min_free_kbytes ? Or is there
anything running inside a memory cgroup with a small limit?
--
Michal Hocko
SUSE Labs
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next prev parent reply other threads:[~2017-03-17 17:13 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <aa4a3217-f94c-0477-b573-796c84255d1e@wiesinger.com>
[not found] ` <c4ddfc91-7c84-19ed-b69a-18403e7590f9@wiesinger.com>
2016-12-09 7:06 ` Still OOM problems with 4.9er kernels Gerhard Wiesinger
2016-12-09 13:40 ` Michal Hocko
2016-12-09 15:52 ` Gerhard Wiesinger
2016-12-09 15:58 ` Gerhard Wiesinger
2016-12-09 16:09 ` Michal Hocko
2016-12-09 16:58 ` Gerhard Wiesinger
2016-12-09 17:30 ` Michal Hocko
2016-12-09 18:01 ` Gerhard Wiesinger
2016-12-09 21:42 ` Vlastimil Babka
2016-12-10 13:50 ` Gerhard Wiesinger
2016-12-12 8:24 ` Michal Hocko
2016-12-23 2:55 ` Minchan Kim
2017-01-01 17:20 ` Gerhard Wiesinger
2017-01-04 8:40 ` Gerhard Wiesinger
2017-01-04 9:11 ` Michal Hocko
2017-02-26 8:40 ` Still OOM problems with 4.9er/4.10er kernels Gerhard Wiesinger
2017-02-27 8:27 ` Michal Hocko
2017-02-28 6:06 ` Gerhard Wiesinger
2017-02-28 8:14 ` Michal Hocko
2017-02-27 9:02 ` Minchan Kim
2017-02-27 9:44 ` Michal Hocko
2017-02-28 5:17 ` Minchan Kim
2017-02-28 8:12 ` Michal Hocko
2017-03-02 7:17 ` Minchan Kim
2017-03-16 6:38 ` Gerhard Wiesinger
2017-03-16 8:27 ` Michal Hocko
2017-03-16 8:47 ` lkml
2017-03-16 9:08 ` Michal Hocko
2017-03-16 9:23 ` lkml
2017-03-16 9:39 ` Michal Hocko
2017-03-17 16:37 ` Gerhard Wiesinger
2017-03-17 17:13 ` Michal Hocko [this message]
2017-03-17 20:08 ` Gerhard Wiesinger
2017-03-19 8:17 ` Gerhard Wiesinger
2017-03-20 1:54 ` Tetsuo Handa
2017-03-19 15:18 ` Michal Hocko
2017-03-19 16:02 ` Gerhard Wiesinger
2017-03-20 3:05 ` Mike Galbraith
2017-03-21 5:59 ` Gerhard Wiesinger
2017-03-21 7:13 ` Mike Galbraith
2017-03-23 7:16 ` Gerhard Wiesinger
2017-03-23 8:38 ` Mike Galbraith
2017-03-23 14:46 ` Tetsuo Handa
2017-03-26 8:36 ` Gerhard Wiesinger
2016-12-09 16:03 ` Still OOM problems with 4.9er kernels Gerhard Wiesinger
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