All of lore.kernel.org
 help / color / mirror / Atom feed
From: Andrew Morton <akpm@linux-foundation.org>
To: Wupeng Ma <mawupeng1@huawei.com>
Cc: <liuye@kylinos.cn>, <hannes@cmpxchg.org>, <mhocko@kernel.org>,
	<david@kernel.org>, <ljs@kernel.org>, <hughd@google.com>,
	<mgorman@techsingularity.net>, <yang@os.amperecomputing.com>,
	<zhangqiuhao@huawei.com>, <wangkefeng.wang@huawei.com>,
	<linux-mm@kvack.org>, <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 0/2] mm: vmscan: fix scan overshoot and ineligible folio scanning
Date: Tue, 11 Aug 2026 18:42:41 -0700	[thread overview]
Message-ID: <20260811184241.e423b81c8a50d5f212af1c3b@linux-foundation.org> (raw)
In-Reply-To: <20260811070849.1332165-1-mawupeng1@huawei.com>

On Tue, 11 Aug 2026 15:08:47 +0800 Wupeng Ma <mawupeng1@huawei.com> wrote:

> shrink_lruvec() drives reclaim in SWAP_CLUSTER_MAX (32) chunks, but
> isolate_lru_folios() may scan far more than that per call on a single
> LRU.  The excess is never charged back, so shrink_lruvec() keeps
> rescanning the same folios round after round.  When reclaim targets a
> lower zone, the same scanner also keeps walking zone-ineligible folios
> that can never satisfy the allocation, inflating nr_reclaimed into a
> false progress that delays the OOM.
> 
> This series fixes both:
> 
>   [1/2] Charge the isolate overshoot against the scan quota so the
>         next round skips already-scanned folios.
>   [2/2] Stop scanning once too many zone-ineligible folios have been
>         skipped, instead of force-isolating them.

This all sounds fairly bad.  Is there some report?  Real-world test
results?  Laboratory test results?  Something to help us understand the
impact of the issues and the situations in which they occur.

Thanks.


  parent reply	other threads:[~2026-08-12  1:42 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-08-11  7:08 [PATCH 0/2] mm: vmscan: fix scan overshoot and ineligible folio scanning Wupeng Ma
2026-08-11  7:08 ` [PATCH 1/2] mm: vmscan: charge isolate overshoot against scan quota Wupeng Ma
2026-08-11  7:08 ` [PATCH 2/2] mm: vmscan: stop scanning ineligible folios after max_nr_skipped Wupeng Ma
2026-08-12  1:42 ` Andrew Morton [this message]
2026-08-12  2:29   ` [PATCH 0/2] mm: vmscan: fix scan overshoot and ineligible folio scanning mawupeng
2026-08-25  0:59     ` mawupeng
2026-08-30  3:18       ` Andrew Morton
2026-09-01  3:12         ` mawupeng

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=20260811184241.e423b81c8a50d5f212af1c3b@linux-foundation.org \
    --to=akpm@linux-foundation.org \
    --cc=david@kernel.org \
    --cc=hannes@cmpxchg.org \
    --cc=hughd@google.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=liuye@kylinos.cn \
    --cc=ljs@kernel.org \
    --cc=mawupeng1@huawei.com \
    --cc=mgorman@techsingularity.net \
    --cc=mhocko@kernel.org \
    --cc=wangkefeng.wang@huawei.com \
    --cc=yang@os.amperecomputing.com \
    --cc=zhangqiuhao@huawei.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.