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was Re: [PATCH] mm: vmscan: always allow writeback during memcg reclaim To: Christoph Hellwig , Johannes Weiner Cc: Deepanshu Kartikey , akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-block@vger.kernel.org References: <20251213083639.364539-1-kartikey406@gmail.com> <20251215041200.GB905277@cmpxchg.org> Content-Language: en-US From: Jens Axboe In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 12/14/25 11:59 PM, Christoph Hellwig wrote: > 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. I'd be all for that. -- Jens Axboe