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=-5.6 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,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 7EAF6C433DB for ; Sat, 27 Feb 2021 00:56:35 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F2C3664DBD for ; Sat, 27 Feb 2021 00:56:34 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F2C3664DBD Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4DB486B008C; Fri, 26 Feb 2021 19:56:34 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 48B526B0092; Fri, 26 Feb 2021 19:56:34 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 383FA6B0095; Fri, 26 Feb 2021 19:56:34 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0034.hostedemail.com [216.40.44.34]) by kanga.kvack.org (Postfix) with ESMTP id 22A106B008C for ; Fri, 26 Feb 2021 19:56:34 -0500 (EST) Received: from smtpin29.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id E2C9E6D8A for ; Sat, 27 Feb 2021 00:56:33 +0000 (UTC) X-FDA: 77862232266.29.844BBC6 Received: from mga07.intel.com (mga07.intel.com [134.134.136.100]) by imf30.hostedemail.com (Postfix) with ESMTP id A93B7E0001B4 for ; Sat, 27 Feb 2021 00:56:32 +0000 (UTC) IronPort-SDR: U2qc57aQCvSunxJ6ZE6VlK1cfWl+GhiZPbljA8jYXsXzNcCTZYtg4fpmrSoP9ACL5cL5WNTdj2 fl9A0EIgwW7A== X-IronPort-AV: E=McAfee;i="6000,8403,9907"; a="250096153" X-IronPort-AV: E=Sophos;i="5.81,210,1610438400"; d="scan'208";a="250096153" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Feb 2021 16:56:28 -0800 IronPort-SDR: gsUOB9ZTOZYp/ns1WJT9bxRzgmff3p+kS3YpgPsI5tSgngoDM1o3s3cwHqZfjZ4aEv/4PvaL40 qsVKiq5yeGLQ== X-IronPort-AV: E=Sophos;i="5.81,210,1610438400"; d="scan'208";a="584781614" Received: from schen9-mobl.amr.corp.intel.com ([10.251.14.198]) by orsmga005-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Feb 2021 16:56:28 -0800 Subject: Re: [PATCH v2 2/3] mm: Force update of mem cgroup soft limit tree on usage excess To: Michal Hocko Cc: Andrew Morton , Johannes Weiner , Vladimir Davydov , Dave Hansen , Ying Huang , linux-mm@kvack.org, cgroups@vger.kernel.org, linux-kernel@vger.kernel.org References: <06f1f92f1f7d4e57c4e20c97f435252c16c60a27.1613584277.git.tim.c.chen@linux.intel.com> <884d7559-e118-3773-351d-84c02642ca96@linux.intel.com> From: Tim Chen Message-ID: <781634ee-ffb9-598d-fdb6-0ae6067448b7@linux.intel.com> Date: Fri, 26 Feb 2021 16:56:28 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit X-Stat-Signature: k74fq5gbrt3aqjjfz8wottmwe19c51t9 X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: A93B7E0001B4 Received-SPF: none (linux.intel.com>: No applicable sender policy available) receiver=imf30; identity=mailfrom; envelope-from=""; helo=mga07.intel.com; client-ip=134.134.136.100 X-HE-DKIM-Result: none/none X-HE-Tag: 1614387392-193808 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 2/26/21 12:52 AM, Michal Hocko wrote: >> >> Michal, >> >> Let's take an extreme case where memcg 1 always generate the >> first event and memcg 2 generates the rest of 128*8-1 events >> and the pattern repeat. > > I do not follow. Events are per-memcg, aren't they? > __this_cpu_read(memcg->vmstats_percpu->targets[target]); > [...] > __this_cpu_write(memcg->vmstats_percpu->targets[target], next); > You are right. My previous reasoning is incorrect as the sampling is done per memcg. I'll do some additional debugging on why memcg is not on the tree. Tim