From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 66A5B26AC3; Thu, 26 Mar 2026 12:31:34 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774528294; cv=none; b=W54fP0OdA/MgKNdGj2Zgqiov6Ksxeg8ZQ6zRy4DvvZs/f8C+1YHCkaf8XNb5c6HRaGOkbeZoLI5RZuB2JSgveZcDcUuQpflWiQ+O3uy/NnXKMLteLYx+oMsb0MBEOqaKxUnLfJKhM8k3At5awIT+58yuApyL5+rc9pcDZkK8iRU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774528294; c=relaxed/simple; bh=mYVRjum22wCN7KHGtoG+3bBzHU9b1WB0/yHYlJYiUEA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=EK2gaqyjqNpLLm9ASSC+Ep9E+si7UvvoaDIRl6Fig/5ltidgAcQlS3grlQ4wY1u51UrdPRoK6qkZUhGyPiONyIRacbs6YgUwTRYuQYC3qIv9p8NQteC+MoBYvrSlDnQ7pmk+RQG0Z7/guf/AfpF/INtBD7Y9nG6YOQ3AjFCiqlY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=YO+CcAyy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="YO+CcAyy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E9A38C116C6; Thu, 26 Mar 2026 12:31:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1774528294; bh=mYVRjum22wCN7KHGtoG+3bBzHU9b1WB0/yHYlJYiUEA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=YO+CcAyyd+UxqKox1MoYb7gIA63PVa6WuBrt1uGObsCwB9tACMuiCvYfP/vltuVVa jcRyyEOUWCnrYb8lEB61MAp4aRGLsEhm6o0nXJla2YhUQRP4VYkOlKDT/6A8nAdhvJ 2UhYM039ed67DUo+KSak6g+0IP4ICnn6PsXO68kBZO6v89sVc7Ip3YojYC531gyH1U MGaazJyZWIRsllwO5f3xVDWsHO9UjmGpCqH8bTYbWTHU+dKgdyjtpqieO8JL3DzHkn kZALWT1p4urNNNloM/U15eRnhwhluAF6W3Yg1o+jn7L2JRFoF3EjLuXIL4VE9AwMIp wwVWUHhLAN3pQ== Date: Thu, 26 Mar 2026 12:31:25 +0000 From: "Lorenzo Stoakes (Oracle)" To: Kairui Song Cc: Andrew Morton , Shakeel Butt , lsf-pc@lists.linux-foundation.org, Johannes Weiner , David Hildenbrand , Michal Hocko , Qi Zheng , Chen Ridong , Emil Tsalapatis , Alexei Starovoitov , Axel Rasmussen , Yuanchu Xie , Wei Xu , Matthew Wilcox , Nhat Pham , Gregory Price , Barry Song <21cnbao@gmail.com>, David Stevens , Vernon Yang , David Rientjes , Kalesh Singh , wangzicheng , "T . J . Mercier" , Baolin Wang , Suren Baghdasaryan , Meta kernel team , bpf@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [LSF/MM/BPF TOPIC] Towards Unified and Extensible Memory Reclaim (reclaim_ext) Message-ID: References: <20260325210637.3704220-1-shakeel.butt@linux.dev> <20260325190547.abb7309fb63473b57b7a90a0@linux-foundation.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: +cc Gregory On Thu, Mar 26, 2026 at 08:06:13PM +0800, Kairui Song wrote: > On Thu, Mar 26, 2026 at 10:05 AM Andrew Morton > wrote: > > > > On Wed, 25 Mar 2026 14:06:37 -0700 Shakeel Butt wrote: > > > > > We should unify both algorithms into a single code path. > > > > I'm here to ask the questions which others fear will sound dumb. > > > > Is it indeed the plan to maintain both implementations? I thought the > > long-term ambition was to knock MGLRU into shape and to drop the legacy LRU? > > I personally also agree on that, so far I'm not aware of any major > issues with MGLRU except some corner cases that are not hard to fix. > Once these are done, I don't see the need for more complexity. Well... :) What about the issues Gregory raised here? https://lore.kernel.org/linux-mm/aaXM7xNSJaJBsety@gourry-fedora-PF4VCD3F/ > > > > And that Linus has expressed such a desire, but my googling fails me. Yup I know, and it'd be ideal to have a single approach, but we definitely need a little more assurance this time that it's the right choice :) In any case I do agree with Shakeel that de-duplicating the code and 'stealing' good ideas from it for both flavours of reclaim at least to start with is a good way forwards. Once we've done that, we can work towards eliminating the 'classic' reclaim if the data supports it. Thanks, Lorenzo