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=-5.4 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, 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 DD38AC4727D for ; Tue, 22 Sep 2020 09:51:40 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 82E88239D4 for ; Tue, 22 Sep 2020 09:51:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chrisdown.name header.i=@chrisdown.name header.b="kWC+smJj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726682AbgIVJvj (ORCPT ); Tue, 22 Sep 2020 05:51:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:51386 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726503AbgIVJvj (ORCPT ); Tue, 22 Sep 2020 05:51:39 -0400 Received: from mail-ej1-x642.google.com (mail-ej1-x642.google.com [IPv6:2a00:1450:4864:20::642]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id C5D08C0613D0 for ; Tue, 22 Sep 2020 02:51:38 -0700 (PDT) Received: by mail-ej1-x642.google.com with SMTP id i26so21886192ejb.12 for ; Tue, 22 Sep 2020 02:51:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chrisdown.name; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to :user-agent; bh=vLhN/ucVLfE69Dl/WKI0HEpcS5fMQFDATogS8fruK+Y=; b=kWC+smJjtT0c9St6jcuRKFe+iC/3MNGMO2hzLmI4h3ukWa//TYGeZk5SPv1bkUzYpe Piq5Gfchg23WCZ9wQAwQMGNwS3SbNdcaDAC2Az/+yjW8h+MjYeKt2dW1g/mome8M5EMI iHbdhnfc6dBx+c0BNKdqAlSk0ap/1jplkFecY= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to:user-agent; bh=vLhN/ucVLfE69Dl/WKI0HEpcS5fMQFDATogS8fruK+Y=; b=rBJu6XUNxBzDirtFV5Zy8j3t1cZ2pnbARHXyEoq1sBCnBw9fXKLlejJYnvPKHaMLyx 39P1mvDzHYKgrWJ7pAyxaxROO2ePqV48rDvRGWwUdohhdMVxhW9pTd/GthFTOO4RUnD2 tjcipIQYLZ1TH2W30ibOQGc1UfSdpvOzMLqAoi2NxZtL/Xi7J4m1w8CYCuJ0uE5RtZ20 xmxVJ8KIaEM/p3N3IMWch+dcU2TNxQuCI4WYvwe+jkfZnCLIM/pTMpqhteeE9slTvadR KVBrzNkAHMN6gpVfmHTswh3pucIv9l0OlnGdGo0A7EP8kbx2/RMp05awHje1c60wK7Zb DIjw== X-Gm-Message-State: AOAM533Hw3ZkfbhxRlzlpp3aD+noQA2UTBkRLfHq7YrPKuu19Srbv2d4 bkcrQH+s5ItzSexr3aTRLUmhDw== X-Google-Smtp-Source: ABdhPJz0OsMdgyayNctU/Uicxzh0FHbqFj8fYde2wyp0iYG7bitVMgqzdrly9+4XgRu7N/ARK6LFpw== X-Received: by 2002:a17:906:af53:: with SMTP id ly19mr3778973ejb.503.1600768297333; Tue, 22 Sep 2020 02:51:37 -0700 (PDT) Received: from localhost ([2620:10d:c093:400::5:7783]) by smtp.gmail.com with ESMTPSA id y14sm10723374eje.10.2020.09.22.02.51.36 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Sep 2020 02:51:36 -0700 (PDT) Date: Tue, 22 Sep 2020 10:51:36 +0100 From: Chris Down To: Chunxin Zang Cc: Michal Hocko , Yafang Shao , Johannes Weiner , Vladimir Davydov , Andrew Morton , Tejun Heo , lizefan@huawei.com, Jonathan Corbet , Alexei Starovoitov , Daniel Borkmann , kafai@fb.com, Song Liu , Yonghong Song , andriin@fb.com, john.fastabend@gmail.com, kpsingh@chromium.org, Cgroups , linux-doc@vger.kernel.org, Linux MM , LKML , netdev , bpf@vger.kernel.org Subject: Re: [External] Re: [PATCH] mm/memcontrol: Add the drop_cache interface for cgroup v2 Message-ID: <20200922095136.GA9682@chrisdown.name> References: <20200921080255.15505-1-zangchunxin@bytedance.com> <20200921081200.GE12990@dhcp22.suse.cz> <20200921110505.GH12990@dhcp22.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.14.7 (2020-08-29) Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Chunxin Zang writes: >My usecase is that there are two types of services in one server. They >have difference >priorities. Type_A has the highest priority, we need to ensure it's >schedule latency、I/O >latency、memory enough. Type_B has the lowest priority, we expect it >will not affect >Type_A when executed. >So Type_A could use memory without any limit. Type_B could use memory >only when the >memory is absolutely sufficient. But we cannot estimate how much >memory Type_B should >use. Because everything is dynamic. So we can't set Type_B's memory.high. > >So we want to release the memory of Type_B when global memory is >insufficient in order >to ensure the quality of service of Type_A . In the past, we used the >'force_empty' interface >of cgroup v1. This sounds like a perfect use case for memory.low on Type_A, and it's pretty much exactly what we invented it for. What's the problem with that?