linux-kernel - Re: [PATCH v4 1/1] mm: vmscan: Reduce throttling due to a failure to make progress

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CALvZod5BmFVdosG=e2NcEzeuzv0W9WifSBmeD48xnn1k+SNRKg@mail.gmail.com>
Date:   Sun, 5 Dec 2021 22:06:27 -0800
From:   Shakeel Butt <shakeelb@...gle.com>
To:     Mel Gorman <mgorman@...hsingularity.net>
Cc:     Andrew Morton <akpm@...ux-foundation.org>,
        Michal Hocko <mhocko@...e.com>,
        Vlastimil Babka <vbabka@...e.cz>,
        Alexey Avramov <hakavlad@...ox.lv>,
        Rik van Riel <riel@...riel.com>,
        Mike Galbraith <efault@....de>,
        Darrick Wong <djwong@...nel.org>, regressions@...ts.linux.dev,
        Linux-fsdevel <linux-fsdevel@...r.kernel.org>,
        Linux-MM <linux-mm@...ck.org>,
        LKML <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v4 1/1] mm: vmscan: Reduce throttling due to a failure to
 make progress

On Fri, Dec 3, 2021 at 11:08 AM Mel Gorman <mgorman@...hsingularity.net> wrote:
>
[...]
> > I am in agreement with the motivation of the whole series. I am just
> > making sure that the motivation of VMSCAN_THROTTLE_NOPROGRESS based
> > throttle is more than just the congestion_wait of
> > mem_cgroup_force_empty_write.
> >
>
> The commit that primarily targets congestion_wait is 8cd7c588decf
> ("mm/vmscan: throttle reclaim until some writeback completes if
> congested"). The series recognises that there are other reasons why
> reclaim can fail to make progress that is not directly writeback related.
>

I agree with throttling for VMSCAN_THROTTLE_[WRITEBACK|ISOLATED]
reasons. Please explain why we should throttle for
VMSCAN_THROTTLE_NOPROGRESS? Also 69392a403f49 claims "Direct reclaim
primarily is throttled in the page allocator if it is failing to make
progress.", can you please explain how?