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 1B860C433DB for ; Sat, 27 Feb 2021 00:58:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D83A264DBD for ; Sat, 27 Feb 2021 00:58:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229698AbhB0A6W (ORCPT ); Fri, 26 Feb 2021 19:58:22 -0500 Received: from mga14.intel.com ([192.55.52.115]:34606 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229863AbhB0A6R (ORCPT ); Fri, 26 Feb 2021 19:58:17 -0500 IronPort-SDR: R9HHtZKp2Ee0WknCguH9utQOmOqPD0Bv/8fldCtNZZbd455FZq15KANag6MHd1QBhDZKYd8VxX rSk/N2A1ChGg== X-IronPort-AV: E=McAfee;i="6000,8403,9907"; a="185348032" X-IronPort-AV: E=Sophos;i="5.81,210,1610438400"; d="scan'208";a="185348032" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Feb 2021 16:56:29 -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 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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