All of lore.kernel.org
 help / color / mirror / Atom feed
From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
To: Michal Hocko <mhocko@kernel.org>
Cc: David Rientjes <rientjes@google.com>,
	linux-mm@kvack.org, Roman Gushchin <guro@fb.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linus Torvalds <torvalds@linux-foundation.org>
Subject: Re: [PATCH 4/4] mm, oom: Fix unnecessary killing of additional processes.
Date: Fri, 7 Sep 2018 22:30:06 +0900	[thread overview]
Message-ID: <9d838223-5a57-e291-eca3-8a4b04a78b65@i-love.sakura.ne.jp> (raw)
In-Reply-To: <20180907115132.GJ19621@dhcp22.suse.cz>

On 2018/09/07 20:51, Michal Hocko wrote:
> On Fri 07-09-18 20:36:31, Tetsuo Handa wrote:
>> On 2018/09/07 20:10, Michal Hocko wrote:
>>>> I can't waste my time in what you think the long term solution. Please
>>>> don't refuse/ignore my (or David's) patches without your counter
>>>> patches.
>>>
>>> If you do not care about long term sanity of the code and if you do not
>>> care about a larger picture then I am not interested in any patches from
>>> you. MM code is far from trivial and no playground. This attitude of
>>> yours is just dangerous.
>>>
>>
>> Then, please explain how we guarantee that enough CPU resource is spent
>> between "exit_mmap() set MMF_OOM_SKIP" and "the OOM killer finds MMF_OOM_SKIP
>> was already set" so that last second allocation with high watermark can't fail
>> when 50% of available memory was already reclaimed.
> 
> There is no guarantee. Full stop! This is an inherently racy land. We
> can strive to work reasonably well but this will never be perfect.

That is enough explanation that we have no choice but mitigate it using
heuristics. No feedback based approach is possible. My or David's patch
has been justified. Thank you!

      reply	other threads:[~2018-09-07 13:30 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-08-04 13:29 [PATCH 1/4] mm, oom: Remove wake_oom_reaper() Tetsuo Handa
2018-08-04 13:29 ` [PATCH 2/4] mm, oom: Check pending victims earlier in out_of_memory() Tetsuo Handa
2018-08-04 13:29 ` [PATCH 3/4] mm, oom: Remove unused "abort" path Tetsuo Handa
2018-08-04 13:29 ` [PATCH 4/4] mm, oom: Fix unnecessary killing of additional processes Tetsuo Handa
2018-08-06 13:45   ` Michal Hocko
2018-08-06 20:19     ` David Rientjes
2018-08-06 20:51       ` Michal Hocko
2018-08-09 20:16         ` David Rientjes
2018-08-10  9:07           ` Michal Hocko
2018-08-10 10:54             ` Tetsuo Handa
2018-08-10 11:16               ` Michal Hocko
2018-08-11  3:12                 ` Tetsuo Handa
2018-08-14 11:33                   ` Michal Hocko
2018-08-19 14:23                     ` Tetsuo Handa
2018-08-20  5:54                       ` Michal Hocko
2018-08-20 22:03                         ` Tetsuo Handa
2018-08-21  6:16                           ` Michal Hocko
2018-08-21 13:39                             ` Tetsuo Handa
2018-08-19 23:45             ` David Rientjes
2018-08-20  6:07               ` Michal Hocko
2018-08-20 21:31                 ` David Rientjes
2018-08-21  6:09                   ` Michal Hocko
2018-08-21 17:20                     ` David Rientjes
2018-08-22  8:03                       ` Michal Hocko
2018-08-22 20:54                         ` David Rientjes
2018-09-01 11:48         ` Tetsuo Handa
2018-09-06 11:35           ` Michal Hocko
2018-09-06 11:50             ` Tetsuo Handa
2018-09-06 12:05               ` Michal Hocko
2018-09-06 13:40                 ` Tetsuo Handa
2018-09-06 13:56                   ` Michal Hocko
2018-09-06 14:06                     ` Tetsuo Handa
2018-09-06 14:16                       ` Michal Hocko
2018-09-06 21:13                         ` Tetsuo Handa
2018-09-07 11:10                           ` Michal Hocko
2018-09-07 11:36                             ` Tetsuo Handa
2018-09-07 11:51                               ` Michal Hocko
2018-09-07 13:30                                 ` Tetsuo Handa [this message]

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=9d838223-5a57-e291-eca3-8a4b04a78b65@i-love.sakura.ne.jp \
    --to=penguin-kernel@i-love.sakura.ne.jp \
    --cc=akpm@linux-foundation.org \
    --cc=guro@fb.com \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@kernel.org \
    --cc=rientjes@google.com \
    --cc=torvalds@linux-foundation.org \
    /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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.