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=-3.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 B588DC433DF for ; Tue, 20 Oct 2020 12:02:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6FE3920770 for ; Tue, 20 Oct 2020 12:02:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2393978AbgJTMCn (ORCPT ); Tue, 20 Oct 2020 08:02:43 -0400 Received: from mx2.suse.de ([195.135.220.15]:42070 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2394130AbgJTMCi (ORCPT ); Tue, 20 Oct 2020 08:02:38 -0400 X-Virus-Scanned: by amavisd-new at test-mx.suse.de Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 01499ABD1; Tue, 20 Oct 2020 12:02:37 +0000 (UTC) References: <20201014190749.24607-1-rpalethorpe@suse.com> <20201016094702.GA95052@blackbook> <20201016145308.GA312010@cmpxchg.org> <20201016171502.GA102311@blackbook> <20201019222845.GA64774@carbon.dhcp.thefacebook.com> <87k0vlwhzt.fsf@suse.de> User-agent: mu4e 1.4.13; emacs 27.1 From: Richard Palethorpe To: Roman Gushchin Cc: Michal =?utf-8?Q?Koutn=C3=BD?= , Johannes Weiner , ltp@lists.linux.it, Andrew Morton , "Shakeel Butt" , "Christoph Lameter" , Michal Hocko , Tejun Heo , Vlastimil Babka , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Michal Hocko Subject: Re: [RFC PATCH] mm: memcg/slab: Stop reparented obj_cgroups from charging root Reply-To: rpalethorpe@suse.de In-reply-to: <87k0vlwhzt.fsf@suse.de> Date: Tue, 20 Oct 2020 13:02:35 +0100 Message-ID: <87h7qpw1es.fsf@suse.de> MIME-Version: 1.0 Content-Type: text/plain Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello, Richard Palethorpe writes: > Hello Roman, > > Roman Gushchin writes: > >> - page_counter_init(&memcg->memory, NULL); >> - page_counter_init(&memcg->swap, NULL); >> - page_counter_init(&memcg->kmem, NULL); >> - page_counter_init(&memcg->tcpmem, NULL); >> + /* >> + * If use_hierarchy == false, consider all page counters direct >> + * descendants of the corresponding root level counters. >> + */ >> + page_counter_init(&memcg->memory, &root_mem_cgroup->memory); >> + page_counter_init(&memcg->swap, &root_mem_cgroup->swap); >> + page_counter_init(&memcg->kmem, &root_mem_cgroup->kmem); >> + page_counter_init(&memcg->tcpmem, &root_mem_cgroup->tcpmem); >> + >> /* >> * Deeper hierachy with use_hierarchy == false doesn't make >> * much sense so let cgroup subsystem know about this > > Perhaps in this case, where the hierarchy is broken, objcgs should also > be reparented directly to root? Otherwise it will still be possible to > underflow the counter in a descendant of root which has use_hierarchy=0, > but also has children. Sorry ignore me, parent_mem_cgroup already selects root. So in the case of a broken hierarchy objcgs are reparented directly to root. -- Thank you, Richard. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Palethorpe Date: Tue, 20 Oct 2020 13:02:35 +0100 Subject: [LTP] [RFC PATCH] mm: memcg/slab: Stop reparented obj_cgroups from charging root In-Reply-To: <87k0vlwhzt.fsf@suse.de> References: <20201014190749.24607-1-rpalethorpe@suse.com> <20201016094702.GA95052@blackbook> <20201016145308.GA312010@cmpxchg.org> <20201016171502.GA102311@blackbook> <20201019222845.GA64774@carbon.dhcp.thefacebook.com> <87k0vlwhzt.fsf@suse.de> Message-ID: <87h7qpw1es.fsf@suse.de> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: ltp@lists.linux.it Hello, Richard Palethorpe writes: > Hello Roman, > > Roman Gushchin writes: > >> - page_counter_init(&memcg->memory, NULL); >> - page_counter_init(&memcg->swap, NULL); >> - page_counter_init(&memcg->kmem, NULL); >> - page_counter_init(&memcg->tcpmem, NULL); >> + /* >> + * If use_hierarchy == false, consider all page counters direct >> + * descendants of the corresponding root level counters. >> + */ >> + page_counter_init(&memcg->memory, &root_mem_cgroup->memory); >> + page_counter_init(&memcg->swap, &root_mem_cgroup->swap); >> + page_counter_init(&memcg->kmem, &root_mem_cgroup->kmem); >> + page_counter_init(&memcg->tcpmem, &root_mem_cgroup->tcpmem); >> + >> /* >> * Deeper hierachy with use_hierarchy == false doesn't make >> * much sense so let cgroup subsystem know about this > > Perhaps in this case, where the hierarchy is broken, objcgs should also > be reparented directly to root? Otherwise it will still be possible to > underflow the counter in a descendant of root which has use_hierarchy=0, > but also has children. Sorry ignore me, parent_mem_cgroup already selects root. So in the case of a broken hierarchy objcgs are reparented directly to root. -- Thank you, Richard.