linux-kernel - retiring laptop_mode? was Re: [PATCH] mm: vmscan: always allow writeback during memcg reclaim

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: <aT-xv1BNYabnZB_n@infradead.org>
Date: Sun, 14 Dec 2025 22:59:11 -0800
From: Christoph Hellwig <hch@...radead.org>
To: Johannes Weiner <hannes@...xchg.org>, Jens Axboe <axboe@...nel.dk>
Cc: Deepanshu Kartikey <kartikey406@...il.com>, akpm@...ux-foundation.org,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	linux-block@...r.kernel.org
Subject: retiring laptop_mode? was Re: [PATCH] mm: vmscan: always allow
 writeback during memcg reclaim

On Sun, Dec 14, 2025 at 11:12:00PM -0500, Johannes Weiner wrote:
> That reasoning doesn't make sense to me. Reclaim is always in response
> to an allocation need. The laptop_mode idea applies to cgroup reclaim
> as much as any other reclaim.
> 
> Now obviously all of this is pretty dated. Reclaim doesn't do
> filesystem writes anymore, and I'm not sure there are a whole lot of
> laptops with rotational drives left, either. Also I doubt anybody is
> still using zone_reclaim_mode (which is where the may_unmap is from).

Yeah.  I wonder if we should retire laptop_mode.  It was a cute hack
back then, but it has it's ugly fingers in way to many places and
should be mostly obsolete by how writeback works these days.