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 X-Spam-Level: X-Spam-Status: No, score=-2.5 required=3.0 tests=MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 2BBD6CA9EC4 for ; Tue, 29 Oct 2019 08:37:37 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id EF1F22086A for ; Tue, 29 Oct 2019 08:37:36 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org EF1F22086A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 6AC196B0005; Tue, 29 Oct 2019 04:37:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 65CA76B0006; Tue, 29 Oct 2019 04:37:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 573706B0007; Tue, 29 Oct 2019 04:37:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0105.hostedemail.com [216.40.44.105]) by kanga.kvack.org (Postfix) with ESMTP id 2B6686B0005 for ; Tue, 29 Oct 2019 04:37:36 -0400 (EDT) Received: from smtpin05.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with SMTP id C5398181AF5CC for ; Tue, 29 Oct 2019 08:37:35 +0000 (UTC) X-FDA: 76096168470.05.copy68_252c5c113dd4e X-HE-Tag: copy68_252c5c113dd4e X-Filterd-Recvd-Size: 2602 Received: from mx1.suse.de (mx2.suse.de [195.135.220.15]) by imf40.hostedemail.com (Postfix) with ESMTP for ; Tue, 29 Oct 2019 08:37:35 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.220.254]) by mx1.suse.de (Postfix) with ESMTP id 11716AE87; Tue, 29 Oct 2019 08:37:32 +0000 (UTC) Date: Tue, 29 Oct 2019 09:37:30 +0100 From: Michal Hocko To: Hillf Danton Cc: linux-mm , Andrew Morton , linux-kernel , Chris Down , Tejun Heo , Roman Gushchin , Johannes Weiner , Shakeel Butt , Matthew Wilcox , Minchan Kim , Mel Gorman Subject: Re: [RFC v2] memcg: add memcg lru for page reclaiming Message-ID: <20191029083730.GC31513@dhcp22.suse.cz> References: <20191026110745.12956-1-hdanton@sina.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191026110745.12956-1-hdanton@sina.com> User-Agent: Mutt/1.10.1 (2018-07-13) 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 Sat 26-10-19 19:07:45, Hillf Danton wrote: > > Currently soft limit reclaim is frozen, see > Documentation/admin-guide/cgroup-v2.rst for reasons. > > This work adds memcg hook into kswapd's logic to bypass slr, > paving a brick for its cleanup later. > > After b23afb93d317 ("memcg: punt high overage reclaim to > return-to-userland path"), high limit breachers are reclaimed one > after another spiraling up through the memcg hierarchy before > returning to userspace. > > We can not add new hook yet if it is infeasible to defer that > reclaiming a bit further until kswapd becomes active. > > It can be defered however because high limit breach looks benign > in the absence of memory pressure, or we ensure it will be > reclaimed soon in the presence of kswapd. This is not true and I have already expressed that in a responsoce to the v1 of this patch. Let me repeat (for the last time hopefully) the high limit is aimed at throttling allocators even when the system is not under a memory pressure. So no, we cannot defer to kswapd. This patchset is ignoring the previous review feedback. You still haven't described any real usecase and any reasons why the existing feature list doesn't satisfy it. Until this is sorted out: Nacked-by: Michal Hocko -- Michal Hocko SUSE Labs