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=-2.2 required=3.0 tests=FROM_EXCESS_BASE64, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,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 38676C742A5 for ; Fri, 12 Jul 2019 03:43:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 0B34021530 for ; Fri, 12 Jul 2019 03:43:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729515AbfGLDnW (ORCPT ); Thu, 11 Jul 2019 23:43:22 -0400 Received: from out4436.biz.mail.alibaba.com ([47.88.44.36]:46903 "EHLO out4436.biz.mail.alibaba.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729293AbfGLDnV (ORCPT ); Thu, 11 Jul 2019 23:43:21 -0400 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R171e4;CH=green;DM=||false|;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e07417;MF=yun.wang@linux.alibaba.com;NM=1;PH=DS;RN=13;SR=0;TI=SMTPD_---0TWfco61_1562902997; Received: from testdeMacBook-Pro.local(mailfrom:yun.wang@linux.alibaba.com fp:SMTPD_---0TWfco61_1562902997) by smtp.aliyun-inc.com(127.0.0.1); Fri, 12 Jul 2019 11:43:18 +0800 Subject: Re: [PATCH 1/4] numa: introduce per-cgroup numa balancing locality, statistic To: Peter Zijlstra Cc: hannes@cmpxchg.org, mhocko@kernel.org, vdavydov.dev@gmail.com, Ingo Molnar , linux-kernel@vger.kernel.org, linux-mm@kvack.org, mcgrof@kernel.org, keescook@chromium.org, linux-fsdevel@vger.kernel.org, cgroups@vger.kernel.org, Mel Gorman , riel@surriel.com References: <209d247e-c1b2-3235-2722-dd7c1f896483@linux.alibaba.com> <60b59306-5e36-e587-9145-e90657daec41@linux.alibaba.com> <3ac9b43a-cc80-01be-0079-df008a71ce4b@linux.alibaba.com> <20190711134754.GD3402@hirez.programming.kicks-ass.net> From: =?UTF-8?B?546L6LSH?= Message-ID: Date: Fri, 12 Jul 2019 11:43:17 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.13; rv:60.0) Gecko/20100101 Thunderbird/60.7.0 MIME-Version: 1.0 In-Reply-To: <20190711134754.GD3402@hirez.programming.kicks-ass.net> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2019/7/11 下午9:47, Peter Zijlstra wrote: [snip] >> + rcu_read_lock(); >> + memcg = mem_cgroup_from_task(p); >> + if (idx != -1) >> + this_cpu_inc(memcg->stat_numa->locality[idx]); > > I thought cgroups were supposed to be hierarchical. That is, if we have: > > R > / \ > A > /\ > B > \ > t1 > > Then our task t1 should be accounted to B (as you do), but also to A and > R. I get the point but not quite sure about this... Not like pages there are no hierarchical limitation on locality, also tasks running in a particular group have no influence to others, not to mention the extra overhead, does it really meaningful to account the stuff hierarchically? Regards, Michael Wang > >> + rcu_read_unlock(); >> +} >> +#endif