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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56D8EC433EF for ; Thu, 21 Jul 2022 11:42:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232513AbiGULme (ORCPT ); Thu, 21 Jul 2022 07:42:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53022 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230284AbiGULmc (ORCPT ); Thu, 21 Jul 2022 07:42:32 -0400 Received: from smtp-out1.suse.de (smtp-out1.suse.de [195.135.220.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A2FE35D0EE; Thu, 21 Jul 2022 04:42:30 -0700 (PDT) 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: Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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