From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=95.215.58.84 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793638377; b=w3xhgjWc/kV8YV2WslA7NRs10syxRci44OrEKigV1so3/ayLtpun6JCPhzHzlC41ztfm eTAmYPlzen3ND0ekLkiGa2hxBON8J6tbpOAJIUvidcd98ZB+81l9iYGE7TEy8tI0VX1j/ uK4Yk39QfnBC/4udU0o2KXs2lHDvepFhXPiece+4wpbq7qhnCRX+8bnW1teTS2AK5W2xx I8L1ETZQ5v22AZ8hSjRQpK0/FphjllXK+aYq+CQtKAbxWcEhA3VokSuloSMmsupkbGePw Y9542zI4mrAjFtYikTgrPapgdKZ0tJoCq1EnFUv5F1K43J9K683+uZYTIJPm+pU9nvg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793638377; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:From:To:Cc:Subject:In-Reply-To: References:User-Agent:Date:Message-ID:MIME-Version:Content-Type: Content-Transfer-Encoding; bh=1TWlg7KRBcE3RU/NzvFLK7aD5NUhim3refNRN/QiCaA=; b=uR13zjEeV5/C0lDcDOJ+xQ3HNEwmBIa6a9rsG6z2aYPOfgorfAk4+LmZBLtLWf4nc+Wl dQNTydsOSACg+jXUqTn7hPZC5O5AoDOBdDDPaXTvoq4DAxWyBkJ1xgVYoPfUarcC+L0tg yxhVmDSvC1MpOmNVNtad/JICLDSLCe6ApLnHFbmIm/Il8p9Q3pLxcbA88ia7RDe5KeeLD G0EwveLR5a3/8mYnmTQxrlPpfoTdM42Wzv2MGF7vuTOwCbu3ipq/KJ6Pp8Q7ESV6ruPMa rVhig/iTJTzAtG+iH8ggddor5EI7DRyoU4PkzcPSuoQ79uQi9KlDiKRc8TOUpL5rzZA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b="ML7/UnYw"; arc=none smtp.remote-ip=95.215.58.84 Received: from mta1.migadu.com (out-84.mta1.migadu.com [95.215.58.84]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3FBC7606E00B for ; Mon, 2 Nov 2026 16:52:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 3FBC7606E00B Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=ML7/UnYw X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=1TWlg7KRBcE3RU/NzvFLK7aD5NUhim3refNRN/QiCaA=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793638373; v=1; x=1794243173; b=ML7/UnYwMPEquYAY5EDZj9SNyn3NruDTdhc8P8QW/LUX4zBFeuZomybTfcUZVxNWuVE3d1/B yuTJem48rHWO9gzghsG5Ir68XyQRbXzdwXYitKImfpU6SmZPrj6mcMkuIxyQlUyNAp94V4QpuWR VxK6L7O8lQUK8qO9VejwCFXY= X-Envelope-To: linux-kernel@vger.kernel.org Received: by mta10.migadu.com with ESMTPS id d321dfeaab60ca30; Mon, 02 Nov 2026 16:52:53 +0000 X-Mizu-Trace-ID: d321dfeaab60ca30 X-Migadu-Flow: FLOW_OUT From: Roman Gushchin To: Tao Cui Cc: Johannes Weiner , Michal Hocko , Shakeel Butt , muchun.song@linux.dev, cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Tao Cui Subject: Re: [RFC PATCH 0/3] mm, memcg: isolate deprecated v1 state from struct mem_cgroup In-Reply-To: <32e80536-64e4-4ae3-a7da-4a37ed415f0a@linux.dev> (Tao Cui's message of "Mon, 2 Nov 2026 21:03:05 +0800") References: <0BEF7489-16EC-44EE-847B-A6AA380BE11F@linux.dev> <32e80536-64e4-4ae3-a7da-4a37ed415f0a@linux.dev> User-Agent: mu4e 1.12.15; emacs 30.2 Date: Mon, 02 Nov 2026 16:52:44 +0000 Message-ID: <7ia41p9341lv.fsf@castle.c.googlers.com> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Tao Cui writes: > Hi Roman, > > =E5=9C=A8 2026/10/30 14:05, Roman Gushchin =E5=86=99=E9=81=93: >> I believe we want to delete this code sooner than later, why would we re= write it before that? >>=20 > > My assumption was that v1 would still be maintained for some time > before its eventual removal, and the goal was to reduce the coupling > between the remaining v1 code and the shared core structures during > that period, rather than to rewrite the implementation for its own > sake. I understand. But personally I don't see big issues with the current code caused by the v1 stuff. Maybe I miss something... The proposed changes on the other hand create difficulties for those who use v1 and maintain some local changes or simple backport upstream fixes. Of course, it's not a reason to not change the upstream code if it's justified, but in this case I'm hardly convinced. > If the expectation is that the remaining v1 implementation will be > removed in the near future, then I agree this work becomes much harder > to justify. > > Am I being too optimistic about how long the remaining v1 code is > expected to stay around? Well, Idk, it was considered deprecated for quite some time already, so maybe announcing that it will be deleted in a year is reasonable? Shakeel, Johannes, Michal, wdyt?