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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,UNPARSEABLE_RELAY autolearn=ham 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 D692DC43387 for ; Thu, 3 Jan 2019 16:57:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id AFC9F217D9 for ; Thu, 3 Jan 2019 16:57:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732434AbfACQ5f (ORCPT ); Thu, 3 Jan 2019 11:57:35 -0500 Received: from out30-132.freemail.mail.aliyun.com ([115.124.30.132]:49292 "EHLO out30-132.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1732412AbfACQ5f (ORCPT ); Thu, 3 Jan 2019 11:57:35 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R351e4;CH=green;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e01451;MF=yang.shi@linux.alibaba.com;NM=1;PH=DS;RN=6;SR=0;TI=SMTPD_---0THTEbts_1546534592; Received: from US-143344MP.local(mailfrom:yang.shi@linux.alibaba.com fp:SMTPD_---0THTEbts_1546534592) by smtp.aliyun-inc.com(127.0.0.1); Fri, 04 Jan 2019 00:56:34 +0800 Subject: Re: [PATCH 2/3] mm: memcontrol: do not try to do swap when force empty To: Shakeel Butt Cc: Michal Hocko , Johannes Weiner , Andrew Morton , Linux MM , LKML References: <1546459533-36247-1-git-send-email-yang.shi@linux.alibaba.com> <1546459533-36247-3-git-send-email-yang.shi@linux.alibaba.com> From: Yang Shi Message-ID: <763b97f5-ea9c-e3e6-7fd9-0ab42cf09ca8@linux.alibaba.com> Date: Thu, 3 Jan 2019 08:56:30 -0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Content-Language: en-US Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 1/2/19 1:45 PM, Shakeel Butt wrote: > On Wed, Jan 2, 2019 at 12:06 PM Yang Shi wrote: >> The typical usecase of force empty is to try to reclaim as much as >> possible memory before offlining a memcg. Since there should be no >> attached tasks to offlining memcg, the tasks anonymous pages would have >> already been freed or uncharged. > Anon pages can come from tmpfs files as well. Yes, but they are charged to swap space as regular anon pages. > >> Even though anonymous pages get >> swapped out, but they still get charged to swap space. So, it sounds >> pointless to do swap for force empty. >> > I understand that force_empty is typically used before rmdir'ing a > memcg but it might be used differently by some users. We use this > interface to test memory reclaim behavior (anon and file). Thanks for sharing your usecase. So, you uses this for test only? > > Anyways, I am not against changing the behavior, we can adapt > internally but there might be other users using this interface > differently. Thanks. Yang > > thanks, > Shakeel