From: Shakeel Butt <shakeel.butt@linux.dev>
To: Matt Fleming <matt@readmodwrite.com>
Cc: Pedro Falcato <pfalcato@suse.de>,
Andrew Morton <akpm@linux-foundation.org>,
Christoph Hellwig <hch@infradead.org>,
Jens Axboe <axboe@kernel.dk>,
Sergey Senozhatsky <senozhatsky@chromium.org>,
Roman Gushchin <roman.gushchin@linux.dev>,
Minchan Kim <minchan@kernel.org>,
kernel-team@cloudflare.com,
Matt Fleming <mfleming@cloudflare.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Chris Li <chrisl@kernel.org>, Kairui Song <kasong@tencent.com>,
Kemeng Shi <shikemeng@huaweicloud.com>,
Nhat Pham <nphamcs@gmail.com>, Baoquan He <bhe@redhat.com>,
Barry Song <baohua@kernel.org>,
Vlastimil Babka <vbabka@kernel.org>,
Suren Baghdasaryan <surenb@google.com>,
Michal Hocko <mhocko@suse.com>,
Brendan Jackman <jackmanb@google.com>, Zi Yan <ziy@nvidia.com>,
Axel Rasmussen <axelrasmussen@google.com>,
Yuanchu Xie <yuanchu@google.com>, Wei Xu <weixugc@google.com>,
David Hildenbrand <david@kernel.org>,
Qi Zheng <zhengqi.arch@bytedance.com>,
Lorenzo Stoakes <ljs@kernel.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm: Require LRU reclaim progress before retrying direct reclaim
Date: Thu, 16 Apr 2026 14:49:28 -0700 [thread overview]
Message-ID: <aeFYrV78Q19c-RnB@linux.dev> (raw)
In-Reply-To: <aeDuVmN8Q6cpNTuT@matt-Precision-5490>
On Thu, Apr 16, 2026 at 03:51:04PM +0100, Matt Fleming wrote:
> On Wed, Apr 15, 2026 at 03:57:25PM +0100, Pedro Falcato wrote:
[...]
>
> > My theory (from merely reading the patch, maybe I missed something) is that
> > a pathological case for this is a lot of folios added to the LRU in a row,
> > that are set referenced (or dirty). Say SWAP_CLUSTER_MAX * MAX_RECLAIM_RETRIES
> > - it will simply OOM too early.
>
> OK yeah I think I see the problem now: this heuristic applies the
> threshold against all reclaimable pages but that falls apart when doing
> SWAP_CLUSTER_MAX chunks of reclaim.
I am not sure I understand the pathological case. Yes SWAP_CLUSTER_MAX is
requested amount of pages to reclaim but the kernel can potentially scan full
memory twice to reclaim that much amount. Though those reclaimed pages can get
stolen but that can still happen today before this patch.
next prev parent reply other threads:[~2026-04-16 21:49 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-04-10 10:15 Matt Fleming
2026-04-13 15:38 ` Vlastimil Babka (SUSE)
2026-04-15 9:11 ` Matt Fleming
2026-04-15 14:57 ` Pedro Falcato
2026-04-16 14:51 ` Matt Fleming
2026-04-16 21:49 ` Shakeel Butt [this message]
2026-04-17 10:35 ` Pedro Falcato
2026-04-16 1:01 ` Shakeel Butt
2026-04-16 14:54 ` Matt Fleming
2026-04-16 1:44 ` Barry Song
2026-04-16 21:58 ` Shakeel Butt
-- strict thread matches above, loose matches on Subject: below --
2026-03-03 11:53 [RFC PATCH 0/1] mm: Reduce direct reclaim stalls with RAM-backed swap Matt Fleming
2026-04-10 9:41 ` [PATCH] mm: Require LRU reclaim progress before retrying direct reclaim Matt Fleming
2026-04-10 10:13 ` Matt Fleming
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=aeFYrV78Q19c-RnB@linux.dev \
--to=shakeel.butt@linux.dev \
--cc=akpm@linux-foundation.org \
--cc=axboe@kernel.dk \
--cc=axelrasmussen@google.com \
--cc=baohua@kernel.org \
--cc=bhe@redhat.com \
--cc=chrisl@kernel.org \
--cc=david@kernel.org \
--cc=hannes@cmpxchg.org \
--cc=hch@infradead.org \
--cc=jackmanb@google.com \
--cc=kasong@tencent.com \
--cc=kernel-team@cloudflare.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=ljs@kernel.org \
--cc=matt@readmodwrite.com \
--cc=mfleming@cloudflare.com \
--cc=mhocko@suse.com \
--cc=minchan@kernel.org \
--cc=nphamcs@gmail.com \
--cc=pfalcato@suse.de \
--cc=roman.gushchin@linux.dev \
--cc=senozhatsky@chromium.org \
--cc=shikemeng@huaweicloud.com \
--cc=surenb@google.com \
--cc=vbabka@kernel.org \
--cc=weixugc@google.com \
--cc=yuanchu@google.com \
--cc=zhengqi.arch@bytedance.com \
--cc=ziy@nvidia.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox