From: Linus Torvalds <torvalds@linux-foundation.org>
To: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Cc: Michal Hocko <mhocko@kernel.org>, linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
David Rientjes <rientjes@google.com>
Subject: Re: [PATCH 0/8] OOM killer/reaper changes for avoiding OOM lockup problem.
Date: Thu, 5 Jul 2018 19:49:58 -0700 [thread overview]
Message-ID: <CA+55aFz87+iXZ_N5jYgo9UFFJ2Tc9dkMLPxwscriAdDKoyF0CA@mail.gmail.com> (raw)
In-Reply-To: <201807060240.w662e7Q1016058@www262.sakura.ne.jp>
On Thu, Jul 5, 2018 at 7:40 PM Tetsuo Handa
<penguin-kernel@i-love.sakura.ne.jp> wrote:
>
> >
> > No, direct reclaim is a way to throttle allocations to the reclaim
> > speed. You would have to achive the same by other means.
>
> No. Direct reclaim is a way to lockup the system to unusable level, by not giving
> enough CPU resources to memory reclaim activities including the owner of oom_lock.
No. Really.
Direct reclaim really really does what Michal claims. Yes, it has
other effects too, and it can be problematic, but direct reclaim is
important.
People have tried to remove it many times, but it's always been a
disaster. You need to synchronize with _something_ to make sure that
the thread that is causing a lot of allocations actually pays the
price, and slows down.
You want to have a balance between direct and indirect reclaim.
If you think direct reclaim is only a way to lock up the system to
unusable levels, you should stop doing VM development.
Linus
next prev parent reply other threads:[~2018-07-06 2:50 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-07-03 14:25 [PATCH 0/8] OOM killer/reaper changes for avoiding OOM lockup problem Tetsuo Handa
2018-07-03 14:25 ` [PATCH 1/8] mm,oom: Don't call schedule_timeout_killable() with oom_lock held Tetsuo Handa
2018-07-03 14:38 ` Michal Hocko
2018-07-03 14:25 ` [PATCH 2/8] mm,oom: Check pending victims earlier in out_of_memory() Tetsuo Handa
2018-07-03 14:25 ` [PATCH 3/8] mm,oom: Fix unnecessary killing of additional processes Tetsuo Handa
2018-07-03 14:58 ` Michal Hocko
2018-07-03 14:25 ` [PATCH 4/8] mm,page_alloc: Make oom_reserves_allowed() even Tetsuo Handa
2018-07-03 14:25 ` [PATCH 5/8] mm,oom: Bring OOM notifier to outside of oom_lock Tetsuo Handa
2018-07-03 14:59 ` Michal Hocko
2018-07-03 14:25 ` [PATCH 6/8] mm,oom: Make oom_lock static variable Tetsuo Handa
2018-07-03 14:25 ` [PATCH 7/8] mm,oom: Do not sleep with oom_lock held Tetsuo Handa
2018-07-03 14:25 ` [PATCH 8/8] mm,page_alloc: Move the short sleep to should_reclaim_retry() Tetsuo Handa
2018-07-03 15:12 ` [PATCH 0/8] OOM killer/reaper changes for avoiding OOM lockup problem Michal Hocko
2018-07-03 15:29 ` Michal Hocko
2018-07-04 2:22 ` penguin-kernel
2018-07-04 7:16 ` Michal Hocko
2018-07-04 7:22 ` Michal Hocko
2018-07-05 3:05 ` Tetsuo Handa
2018-07-05 7:24 ` Michal Hocko
2018-07-06 2:40 ` Tetsuo Handa
2018-07-06 2:49 ` Linus Torvalds [this message]
2018-07-07 1:12 ` Tetsuo Handa
2018-07-09 7:45 ` Michal Hocko
2018-07-06 5:56 ` Michal Hocko
2018-07-10 3:57 ` Tetsuo Handa
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=CA+55aFz87+iXZ_N5jYgo9UFFJ2Tc9dkMLPxwscriAdDKoyF0CA@mail.gmail.com \
--to=torvalds@linux-foundation.org \
--cc=akpm@linux-foundation.org \
--cc=linux-mm@kvack.org \
--cc=mhocko@kernel.org \
--cc=penguin-kernel@i-love.sakura.ne.jp \
--cc=rientjes@google.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 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.