From: Christoph Hellwig <hch@infradead.org>
To: Johannes Weiner <hannes@cmpxchg.org>, Jens Axboe <axboe@kernel.dk>
Cc: Deepanshu Kartikey <kartikey406@gmail.com>,
akpm@linux-foundation.org, linux-mm@kvack.org,
linux-kernel@vger.kernel.org, linux-block@vger.kernel.org
Subject: retiring laptop_mode? was Re: [PATCH] mm: vmscan: always allow writeback during memcg reclaim
Date: Sun, 14 Dec 2025 22:59:11 -0800 [thread overview]
Message-ID: <aT-xv1BNYabnZB_n@infradead.org> (raw)
In-Reply-To: <20251215041200.GB905277@cmpxchg.org>
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.
next prev parent reply other threads:[~2025-12-15 6:59 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-12-13 8:36 Deepanshu Kartikey
2025-12-14 23:49 ` Andrew Morton
2025-12-15 4:12 ` Johannes Weiner
2025-12-15 4:51 ` Deepanshu Kartikey
2025-12-15 19:42 ` Yuanchu Xie
2025-12-15 20:22 ` Johannes Weiner
2025-12-19 5:13 ` Kairui Song
2025-12-15 6:59 ` Christoph Hellwig [this message]
2025-12-15 16:33 ` retiring laptop_mode? was " Jens Axboe
2025-12-15 20:08 ` Johannes Weiner
2025-12-16 2:23 ` Jens Axboe
2025-12-16 7:41 ` Christoph Hellwig
2025-12-16 18:52 ` Johannes Weiner
2025-12-16 18:54 ` Jens Axboe
2025-12-16 23:23 ` Shakeel Butt
2025-12-17 19:59 ` Johannes Weiner
2025-12-18 7:21 ` Shakeel Butt
2025-12-17 19:34 ` Michal Hocko
2025-12-18 6:00 ` Christoph Hellwig
2025-12-15 17:49 ` Michal Hocko
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