From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 556D33446C7; Thu, 23 Jul 2026 10:23:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784802186; cv=none; b=q3j3J/gm0RalanuGPuKYMx6JS7zniBgGww6o4BLJfhDP7sGRvarHdLEcAkpSq8iQHDu5+382v+ii0NYPlKHrVqUWX2NUR9WEpWn1BTedBCA9KcKsi8NwXiBoWwuQ93ZkZ/svqwaylLMzj3/c+jPPf4GqTXNV2BrkucK4XsFhPNs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784802186; c=relaxed/simple; bh=f0CAk3+3gg8VDdWCWyve26MrnID1wdXz3t/Oj0vbbbk=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=qxMwNnCErh+NxU7/8xhkI12RT5Vsr0weKCbfvxoqaxV4p7sE70OC2Ju4yPpsDd5ctaSWfiEsh7GEoh+56CiwXPcHst1djd/ZB6xlZP7IHQVT/UICmBDg1FNChkFwxiKA8eA4HVe1RduPBR7KxsHd+YXRkQc4JNygzA5du8iDREI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=EwNYbYnp; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="EwNYbYnp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id E7C841F00A3A; Thu, 23 Jul 2026 10:23:01 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784802185; bh=go7Y++9i2ovOLRuatKWJusZrB2J2y0mZiW0U9qh+nWA=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=EwNYbYnpJeqhXkEBVp4z5DHKL2WlH3S3PqlMxBJ77F4koUqIBvAMjS3lSxJT/oMbf v5a1dHjfgX71d/JwY4TJbluGAXLVVFyKmZ2oLaRQpFlO2Gt+ABzPpjZkM/Ctnc/8mN +CZ4lYoYf7qgaSVt7LSVyt8TdUAHoB8sS4TRwZ4U4WIpOrO0po4GONGt7tlCBb3kDm IDzPjsvcpeaz1ADvFW7uEFdg/oWxlSJVvmV+7sHYFBeOxzrxA6GM5aKouZaVZ3pH+H tlnT0YsNiM/lr9JdMptl51uMiLPZbaV5fs6je+9bcfmpVfznMWszRR7KcjAH+HOW/u +cnbHEC3Oee0Q== Message-ID: <67e1219e-9d47-4a30-a8dd-fdcf03229f58@kernel.org> Date: Thu, 23 Jul 2026 12:22:58 +0200 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 4/4] mm: page_alloc: fix non-movable reclaim storm in defrag_mode Content-Language: en-US To: Andrew Morton , Johannes Weiner , Greg Kroah-Hartman , Sasha Levin Cc: Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Zi Yan , David Hildenbrand , Lorenzo Stoakes , "Liam R . Howlett" , Mike Rapoport , Shakeel Butt , linux-mm@kvack.org, linux-kernel@vger.kernel.org, stable@vger.kernel.org References: <20260722150006.3848560-1-hannes@cmpxchg.org> <20260722150006.3848560-5-hannes@cmpxchg.org> <20260722162207.31a2c491ffaf36d1e8948c14@linux-foundation.org> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; keydata= xsFNBFZdmxYBEADsw/SiUSjB0dM+vSh95UkgcHjzEVBlby/Fg+g42O7LAEkCYXi/vvq31JTB KxRWDHX0R2tgpFDXHnzZcQywawu8eSq0LxzxFNYMvtB7sV1pxYwej2qx9B75qW2plBs+7+YB 87tMFA+u+L4Z5xAzIimfLD5EKC56kJ1CsXlM8S/LHcmdD9Ctkn3trYDNnat0eoAcfPIP2OZ+ 9oe9IF/R28zmh0ifLXyJQQz5ofdj4bPf8ecEW0rhcqHfTD8k4yK0xxt3xW+6Exqp9n9bydiy tcSAw/TahjW6yrA+6JhSBv1v2tIm+itQc073zjSX8OFL51qQVzRFr7H2UQG33lw2QrvHRXqD Ot7ViKam7v0Ho9wEWiQOOZlHItOOXFphWb2yq3nzrKe45oWoSgkxKb97MVsQ+q2SYjJRBBH4 8qKhphADYxkIP6yut/eaj9ImvRUZZRi0DTc8xfnvHGTjKbJzC2xpFcY0DQbZzuwsIZ8OPJCc LM4S7mT25NE5kUTG/TKQCk922vRdGVMoLA7dIQrgXnRXtyT61sg8PG4wcfOnuWf8577aXP1x 6mzw3/jh3F+oSBHb/GcLC7mvWreJifUL2gEdssGfXhGWBo6zLS3qhgtwjay0Jl+kza1lo+Cv BB2T79D4WGdDuVa4eOrQ02TxqGN7G0Biz5ZLRSFzQSQwLn8fbwARAQABzSNWbGFzdGltaWwg QmFia2EgPHZiYWJrYUBrZXJuZWwub3JnPsLBsAQTAQoAWhYhBKlA1DSZLC6OmRA9UCJPp+fM gqZkBQJqFFy6GxSAAAAAAAQADm1hbnUyLDIuNSsxLjEyLDIsMgIbAwUJGtCBUAULCQgHAwUV CgkICwUWAgMBAAIeBQIXgAAKCRAiT6fnzIKmZJIUEADFx/tREzUImHrEwVHeSvDFmA7tJysI UVrlvrM09E7GIuzphzv7jYmo8n3ANpCczLEVr4G0syYQdTigaZgv3+FQDIIzhKih1IHhu1Ei XHlywNWKnQxxQEUNi5Mwx43wQz5XVw9F1A7gtKBKNtfogO511hAbrzagrYajyQacEJ/+sfhZ 9Da8ltHIXD8pcYaHUfQgEusCgmEd9+KrUwrTbckFKmYq5chuE6yJ4J0EmWknL096jIE6CnzF FRslQ3B1UKDjxVsm1ZHfir5NeWszLkTvGFsddFaWTgh8UycESG6VQzKXjjewXu2pG7YQYRpj QKm1W5X2TkwWkXRBZTmfmbhxIUMh3+zf5wQ463rSmDN/8v81tdqBtAW6rH/kzg1GvkaTHXn0 507yEHFzBksk2viAuIxxr7km8+/KARYLIdGtx30EG8cKzAUZOK6WqxtNCsXUJNrVE8CWrCaD icoNu7Fs1c5hmPHdSTnU48ce67449DdnO4neLSNhRiGlMHJgfJUmgrxu/hcYeOZ3haWmEQ2w uW1Mh01OHi8QZHCEyAbABrPs9GUgccc/4eYXX9hIgxfSkYzn8f+8NuIFPWl/0uTvjgqU29FQ SbzOLxHq9439Ox40G5mS5eZXRGxITYR+6TXvRGI6P/264jvflnr/pDGUttaikU+0W+1uxgKH cmYbEc7ATQRbGTU1AQgAn0H6UrFiWcovkh6EXVcl+SeqyO6JHOPm+e9Wu0Vw+VIUvXZVUVVQ La1PQDUi6j00ChlcR66g9/V0sPIcSutacPKfdKYOBvzd4rlhL8rfrdEsQw5ApZxrA8kYZVMh FmBRKAa6wos25moTlMKpCWzTH84+WO5+ziCTsTUZASAToz3RdunTD+vQcHj0GqNTPAHK63sf bAB2I0BslZkXkY1RLb/YhuA6E7JyEd2pilZOrIuBGl/5q2qSakgnAVFWFBR/DO27JuAksYnq +aH8vI0xGvwn75KqSk4UzAkDzWSmO4ZHuahKtQgZNsMYV+PGayRBX9b9zbldzopoLBdqHc4n jQARAQABwsF8BBgBCgAmAhsMFiEEqUDUNJksLo6ZED1QIk+n58yCpmQFAmfIHFQFCRYU6J8A CgkQIk+n58yCpmS2PA//bqN1LfcotmArgElsa+0EGZSQlYgK48pm8WAeTXTngudP9IJ4SuKY HR5RNjHcBeqN+Me0zxRqYzRb8nGanHEkDyf4Im8DQM8d6vbyU+FcPmG4skud4kgS1zMHnlVd SXfSIwKC/hKgdHG8aBV7545Lz9X6Iohea+94wneD0aw/hqF+QWewGZhWJriWAZtvEkzNjQOi 4U9F/trLten/x7bpphDSnDMKJtITbtzATT1Dq7o7VpIUK1nCTQALMuMjKCdi8OdU/+V+R3O4 0PXWvX8qrvqYapVbZ+9KqT74FsuB0Ya9uXwgBF2Q6cRuETZk5vqaqKxzqoQZCO8AOz/58j6O 2RHNy/mZEN+7tJ5Tsq42zVJ4jxsT8b9YplavCMsnBgDeRWhcbYhCyttoL7nYISyWg4kQYZ/P wIV3OuNv2f8iKYsxNsRuClOAF82+gvqOy1/1pprFjy8uo2pkoOrb63aOP3vO5VHnRKgra6dq NcaZ+c6J4H+nEJGi2SkHAUJz5oBzuThvPudLvPA/SK8sKoM01IRxSihev/S/5WLazXB1PGem OCbvzC1IjWJJraxiDJ5IygokapUa2RP7+WBR22skQ3SSl6G107QgWKSyTOGWEaRmV53vxQLV jXuCmzSSasTL60zq5yGrT4/DYQVSNEUiUbG4pYekxJujNeEDkUlky0Y= In-Reply-To: <20260722162207.31a2c491ffaf36d1e8948c14@linux-foundation.org> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit + Greg and Sasha On 7/23/26 01:22, Andrew Morton wrote: > On Wed, 22 Jul 2026 10:56:47 -0400 Johannes Weiner wrote: > >> >> Fixes: e3aa7df331bc ("mm: page_alloc: defrag_mode") >> Cc: >> Signed-off-by: Johannes Weiner > > This cc:stable fix doesn't apply to current mainline because the > preceding non-cc:stable patches get in the way. > > This means that the -stable maintainers will have to ask you to redo > the fix to make it backportable. And you'll then be preparing a patch > which hasn't had standalone testing in mainline. All very cumbersome. Or they backport the whole series, even if only 4/4 has a Fixes: tag. > So is it practical to make the fix come first, as a cc:stable hotfix so > we can upstream the other patches in the next merge window? I think it can't come first, it's simply a complex fix that can't be done in a single patch that would be reviewable. 3/4 is certainly a strict dependency. I'm not sure if 2/4 as well. Perhaps 2/4 does deserve a Fixes: tag and Cc: stable on its own, as it also fixes a defrag_mode deficiency. > (An alternative would be to put cc:stable on all four patches. That's > a bit abusive but we do it rarely). I don't think it's necessary, the stable team are quite capable of figuring out the deps and backporting them with a Stable-dep-off: tag. IIRC the "fake" tagging is discouraged? Maybe they can clarify. > Either way, I'll get these into mm.git for testing while we await > review on [4/4], thanks. >