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 BA8C1C2D0E2 for ; Tue, 22 Sep 2020 12:43:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6597C2396D for ; Tue, 22 Sep 2020 12:43:48 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chrisdown.name header.i=@chrisdown.name header.b="u3lMp8Ty" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726635AbgIVMnr (ORCPT ); Tue, 22 Sep 2020 08:43:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49714 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726586AbgIVMnr (ORCPT ); Tue, 22 Sep 2020 08:43:47 -0400 Received: from mail-ej1-x643.google.com (mail-ej1-x643.google.com [IPv6:2a00:1450:4864:20::643]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 36C4BC0613CF for ; Tue, 22 Sep 2020 05:43:47 -0700 (PDT) Received: by mail-ej1-x643.google.com with SMTP id gx22so13598924ejb.5 for ; Tue, 22 Sep 2020 05:43:47 -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:in-reply-to:user-agent; bh=EZVYPQDM745h290MwDvoCECH4RGR18nCNuRmCWFdNCw=; b=u3lMp8TydI2QP6QNm/pAfrLJ7GK81BNOYZKPoUBMxHXf4Zv6JaWyqYjI6FQPcXhjzp 1zO/CvtrgtTa4Fi3WVskIRg9vs7l9p0r8mVyusxvjIvYBobSb98S1lsxHtK9IV8Sz0n5 D5Vu7pA2LMs/XlZnl0jLCRk7QR2nUmaVMGDC8= 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:in-reply-to:user-agent; bh=EZVYPQDM745h290MwDvoCECH4RGR18nCNuRmCWFdNCw=; b=GEI8qGAJe+/BqroQipiJH18zWyZqojsqDCQXsw4qXok6yVErpvG0gu+gjcG1Dhk1EX QgYjGdTAWR3Y/1AHzuNJbSP66IFsK4DDynnBc5gOxn4LJAgdhAeqm6gtg//2XIEZMdAq jk/rUpZy85lpu5CqzPfgmLqw9QPox6HLi2b3Jx7teh0Z0cdQTTiViNeYm55R4HDuYoyf e0GZrqbASBcnV8dZ/krRD3l5ESbqF2lFKo7yo0zzAb1WSgTt4vZNWo3BARc8LmytW8Q/ 41hitPV+XSTDvNrhFxjb808UZIoHqr5ThRMNWI+pBoDJpszMyF/QbjV4ahMfmMR42i3d v7WQ== X-Gm-Message-State: AOAM533Relp/8FdPRZmvTbRCOg9VRm/vfvH54RWDvY1XH5DXnxcfltqV YE3Sh5QO6OPsvBajOk8S68NQ2w== X-Google-Smtp-Source: ABdhPJxeRbmQoeE/o8aQAa0StUUCmpBOrgC9ypGDnyDhtAgYjksvLFNIREqXBlQ7sDPdAz9jO4xmMA== X-Received: by 2002:a17:907:408e:: with SMTP id nt22mr4584356ejb.169.1600778625780; Tue, 22 Sep 2020 05:43:45 -0700 (PDT) Received: from localhost ([2620:10d:c093:400::5:e90b]) by smtp.gmail.com with ESMTPSA id v17sm11272766ejj.55.2020.09.22.05.43.45 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 22 Sep 2020 05:43:45 -0700 (PDT) Date: Tue, 22 Sep 2020 13:43:44 +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: <20200922124344.GA34296@chrisdown.name> References: <20200921080255.15505-1-zangchunxin@bytedance.com> <20200921081200.GE12990@dhcp22.suse.cz> <20200921110505.GH12990@dhcp22.suse.cz> <20200922095136.GA9682@chrisdown.name> <20200922104252.GB9682@chrisdown.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.14.7 (2020-08-29) Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Chunxin Zang writes: >Please forgive me for not being able to understand why setting >memory.low for Type_A can solve the problem. >In my scene, Type_A is the most important, so I will set 100G to memory.low. >But 'memory.low' only takes effect passively when the kernel is >reclaiming memory. It means that reclaim Type_B's memory only when >Type_A in alloc memory slow path. This will affect Type_A's >performance. >We want to reclaim Type_B's memory in advance when A is expected to be busy. That's what kswapd reclaim is for, so this distinction is meaningless without measurements :-)