From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1B0F1C433EF for ; Thu, 21 Jul 2022 11:42:32 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id A5BCA8E0003; Thu, 21 Jul 2022 07:42:31 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id A0C178E0001; Thu, 21 Jul 2022 07:42:31 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 8D39D8E0003; Thu, 21 Jul 2022 07:42:31 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 7FEE48E0001 for ; Thu, 21 Jul 2022 07:42:31 -0400 (EDT) Received: from smtpin27.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay06.hostedemail.com (Postfix) with ESMTP id 59AE9AB1E9 for ; Thu, 21 Jul 2022 11:42:31 +0000 (UTC) X-FDA: 79710919302.27.32E7B45 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by imf31.hostedemail.com (Postfix) with ESMTP id A585A2001B for ; Thu, 21 Jul 2022 11:42:30 +0000 (UTC) Received: from relay2.suse.de (relay2.suse.de [149.44.160.134]) by smtp-out1.suse.de (Postfix) with ESMTP id 2389B347EB; Thu, 21 Jul 2022 11:42:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1658403749; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=BkvbSMivb/aWXIlzYNPZoVB/iKbqXT76LFZqzry9Fz4=; b=r2465AG3bndbjlFwjkJAWIovGGRSvB4ub7P3vDo/JON7K4EOcDSeD0D4aKvmMfKaVYRcsN q071il98/zaQkOiititSJGsdWBY7fcTNeVkfW8TDsWHrmu1KKFWJmlRfJ6yd/MKGdXD5C2 //MdG7ABC4+aDFuIp0M2Obnx5rxqfQY= Received: from suse.cz (unknown [10.100.201.86]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by relay2.suse.de (Postfix) with ESMTPS id 5E9632C149; Thu, 21 Jul 2022 11:42:28 +0000 (UTC) Date: Thu, 21 Jul 2022 13:42:25 +0200 From: Michal Hocko To: Shakeel Butt Cc: Yosry Ahmed , Johannes Weiner , Roman Gushchin , Muchun Song , Andrew Morton , Matthew Wilcox , Vlastimil Babka , David Hildenbrand , Miaohe Lin , NeilBrown , Alistair Popple , Suren Baghdasaryan , Peter Xu , LKML , Cgroups , Linux MM Subject: Re: [PATCH v4] mm: vmpressure: don't count proactive reclaim in vmpressure Message-ID: References: <20220714064918.2576464-1-yosryahmed@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1658403751; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=BkvbSMivb/aWXIlzYNPZoVB/iKbqXT76LFZqzry9Fz4=; b=guEhah8u35cpFK81zSrcCgXP/VC5ikUbKA1lMx7CW3ZErGPa3AftMS/a6Ed2YVaLUYwKI/ rH+h+UY/WnadiFKKSKDA8glaxFHvawAirf04Nf8GjxcoRs5GOYg8Gy/38rlHbBL88FXHhX oy/w3+UD1xCzYF0Umc+vBAXRAFiwXLc= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1658403751; a=rsa-sha256; cv=none; b=7fPQD1uxCGY7pf+td/yrV9mQzsB5LExbwef+OqKIP3Qb9JdlV+ZcR/R3DgU6j09935EH3T J346pjTbN9g8ivLyw6wuIRJwkHwVaoh4LLQOYRYVLER6XH/SM7/AIp2siaDlawTE9sRtkN Nzz+134Bi8cDC3ImqrYdsx3YaS2ta3U= ARC-Authentication-Results: i=1; imf31.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=r2465AG3; dmarc=pass (policy=quarantine) header.from=suse.com; spf=pass (imf31.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.28 as permitted sender) smtp.mailfrom=mhocko@suse.com X-Rspamd-Queue-Id: A585A2001B Authentication-Results: imf31.hostedemail.com; dkim=pass header.d=suse.com header.s=susede1 header.b=r2465AG3; dmarc=pass (policy=quarantine) header.from=suse.com; spf=pass (imf31.hostedemail.com: domain of mhocko@suse.com designates 195.135.220.28 as permitted sender) smtp.mailfrom=mhocko@suse.com X-Rspamd-Server: rspam12 X-Rspam-User: X-Stat-Signature: wbe6d5fcf1wfci9bntemswz5gro4un15 X-HE-Tag: 1658403750-355217 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed 20-07-22 10:49:53, Shakeel Butt wrote: > On Wed, Jul 20, 2022 at 2:24 AM Michal Hocko wrote: > > > [...] > > > > I think what we are missing here is > > - explain that this doesn't have any effect on existing users of > > vmpressure user interface because that is cgroup v1 and memory.reclaim > > is v2 feature. This is a trivial statement but quite useful for future > > readers of this commit > > - explain the effect on the networking layer and typical usecases > > memory.reclaim is used for currently and ideally document that. > > I agree with the above two points (Yosry, please address those) but > the following third point is orthogonal and we don't really need to > have an answer for this patch to be accepted. > > > - how are we going to deal with users who would really want to use > > memory.reclaim interface as a replacement for existing hard/high > > memory reclaim? Is that even something that the interface is intended > > for? > > I do agree that this question is important. Nowadays I am looking at > this from a different perspective and use-case. More concretely how > (and why) to replace vmpressure based network throttling for cgroup > v2. I will start a separate thread for that discussion. I think we should be good to document this side effect for now. If you have a plan to change to vmpressure based throttling then only better. But one way or the other impact of the memory.reclaim interface on netwroking should be documented properly. -- Michal Hocko SUSE Labs