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=-5.3 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,URIBL_BLOCKED,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 BDAA1C2D0E2 for ; Tue, 22 Sep 2020 10:43:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5D45D208A9 for ; Tue, 22 Sep 2020 10:43:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chrisdown.name header.i=@chrisdown.name header.b="NTQO2+kj" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726531AbgIVKmz (ORCPT ); Tue, 22 Sep 2020 06:42:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59340 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726514AbgIVKmz (ORCPT ); Tue, 22 Sep 2020 06:42:55 -0400 Received: from mail-ed1-x541.google.com (mail-ed1-x541.google.com [IPv6:2a00:1450:4864:20::541]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BCD5BC0613D0 for ; Tue, 22 Sep 2020 03:42:54 -0700 (PDT) Received: by mail-ed1-x541.google.com with SMTP id c8so15697002edv.5 for ; Tue, 22 Sep 2020 03:42:54 -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=d1+yTgS/nDdjZEJi5XLFsbasjOospBGkZinpc5mGS48=; b=NTQO2+kjCrvdbjEFL+8qa0xnM8j2aFkI4YIcOCf4DCtwzIrmLrmov9WqKk+Wh+vi4c gCqSG+yI5jbUdW0ZVX5erknsxE3avoRsk7dEgDoLscAWzHi9kia5w25FMnOnzVtYelst N+N+jIm2n4VgPnzMfUEdrh/Ou7cDYiyq+cqLg= 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=d1+yTgS/nDdjZEJi5XLFsbasjOospBGkZinpc5mGS48=; b=fFBNCr+OqS+W4wifXgGFKk6MYoWmY/axQZ3a0VhKeayJzEo6tROlQEzSbSfj423eGf UfU7v4TYksNqPQwZNUavUvKyvtwulOkV0p6h2ecalMq+KmyOjYOr6sJOT2hwUNtbKyJQ s5RVPWfeD26RJybqGSwZ7Kb/+w/L5RIrRvskHANN3lJZe36gdXQlb6rUEoiItTxA1JLV ovUWB7Boa11exIsZwvZgRhxw/vu6pUt5rrvxQK8wbKGWICRpxkZpvihMHJ+DYtW5Xi70 CyNvFc+la8Cv1OrOjcRR3+LO37ryfWVDHaJa9mhT5RhwMjlc/EKStqFaBKk4jjb/YlIO eBZg== X-Gm-Message-State: AOAM530lZIKWmLRnXPfYI2oZss3v5Ouage7oFqnRBW1u3/E8dtG5Efmv oRFCWYC7j1et5IDDu9TCLUxUBA== X-Google-Smtp-Source: ABdhPJyLjjf0N1v9YU9XDgeN4pEzCTJKyLcJJ5cAqsBsxayr1kBl20EtWfgNKP9UQ2nNgW/Tp4JosQ== X-Received: by 2002:a05:6402:202a:: with SMTP id ay10mr3317444edb.36.1600771373203; Tue, 22 Sep 2020 03:42:53 -0700 (PDT) Received: from localhost ([2620:10d:c093:400::5:7783]) by smtp.gmail.com with ESMTPSA id 16sm10724717edx.72.2020.09.22.03.42.52 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Sep 2020 03:42:52 -0700 (PDT) Date: Tue, 22 Sep 2020 11:42:52 +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: <20200922104252.GB9682@chrisdown.name> References: <20200921080255.15505-1-zangchunxin@bytedance.com> <20200921081200.GE12990@dhcp22.suse.cz> <20200921110505.GH12990@dhcp22.suse.cz> <20200922095136.GA9682@chrisdown.name> 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: linux-doc@vger.kernel.org Chunxin Zang writes: >On Tue, Sep 22, 2020 at 5:51 PM Chris Down wrote: >> >> 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? > >But we cannot estimate how much memory Type_A uses at least. memory.low allows ballparking, you don't have to know exactly how much it uses. Any amount of protection biases reclaim away from that cgroup. >For example: >total memory: 100G >At the beginning, Type_A was in an idle state, and it only used 10G of memory. >The load is very low. We want to run Type_B to avoid wasting machine resources. >When Type_B runs for a while, it used 80G of memory. >At this time Type_A is busy, it needs more memory. Ok, so set memory.low for Type_A close to your maximum expected value.