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 Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id BFFD0C433F5 for ; Wed, 9 Mar 2022 00:07:24 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 521FE8D0002; Tue, 8 Mar 2022 19:07:24 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 4AA048D0001; Tue, 8 Mar 2022 19:07:24 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 370BB8D0002; Tue, 8 Mar 2022 19:07:24 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (relay.hostedemail.com [64.99.140.25]) by kanga.kvack.org (Postfix) with ESMTP id 238B58D0001 for ; Tue, 8 Mar 2022 19:07:24 -0500 (EST) Received: from smtpin11.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay13.hostedemail.com (Postfix) with ESMTP id E4F0B604FD for ; Wed, 9 Mar 2022 00:07:23 +0000 (UTC) X-FDA: 79222908366.11.34F6ADF Received: from mail-ej1-f45.google.com (mail-ej1-f45.google.com [209.85.218.45]) by imf17.hostedemail.com (Postfix) with ESMTP id 72C9B4000D for ; Wed, 9 Mar 2022 00:07:23 +0000 (UTC) Received: by mail-ej1-f45.google.com with SMTP id qa43so1336525ejc.12 for ; Tue, 08 Mar 2022 16:07:23 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux-foundation.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=KfA4JgIAwrzcTd/4yRkk1J8RUcB4FSjox1guvVqXM6M=; b=gOPY1r/wzB5jYwuwRc6y3Yxrhd0fGC6yPlpf9+UB9omWnf6GTz6QTzPrdA7qfkJfHM lJ75Qqxmjo1vD3lxkPsHj+ZIudClKUQfypotCbBgEG08N3dw/YuJs8qjwqUXz2qOvy2j h6d9I3cmIm/w83PdSf1CY1Sj7DgY3Rbzp9ZI8= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=KfA4JgIAwrzcTd/4yRkk1J8RUcB4FSjox1guvVqXM6M=; b=HZkXXYqbg41jDf7IBQmL7xa+VAFduElp8h7WnXVvNZJxWkWAbD5Le62A1MBcTgoaKi zWGSMf8fsZg2JdxfCpCnbXpwhoctu+b5XlyYMp9BGcfuFfzopyzedFMxNUuZXp79fmFj Ml33Ja7aBvclRiHT5vPBejEo81MGdz9gg3TWjzLqRuuvVebzKB16FctH4awR8oIyC45r xmuk/K1CPJADuWUnC39tZzJXmhYG+/7LuGMBG/Pr0L2vbsrNftOXPXURqNNh/DIeAeM6 KQDhjy2ZFylYVqYmM1oHuI6JkyoIsp9HJPcG6xCrRlnOxRMp7Vhlcd6IBeGQFUHZywGa JsGA== X-Gm-Message-State: AOAM533IIx3A592t834cAkkCXNXTMV4AoLvdQOoXnFPLzDGqJZRzO2fo bn3lSgNb4ky+yNNv6RUztvLjopj7TZhU16Q0Bn0= X-Google-Smtp-Source: ABdhPJzRPCOo2jP7RMPA9FVwqBxi2U7fCAls3XdeETopZER2Ty7PDZq3vt8teQoY/mssWV/5oiKRJQ== X-Received: by 2002:a17:907:a0c9:b0:6da:9614:2626 with SMTP id hw9-20020a170907a0c900b006da96142626mr15248700ejc.100.1646784441857; Tue, 08 Mar 2022 16:07:21 -0800 (PST) Received: from mail-ej1-f54.google.com (mail-ej1-f54.google.com. [209.85.218.54]) by smtp.gmail.com with ESMTPSA id t7-20020a1709063e4700b006da6357b1c0sm85322eji.196.2022.03.08.16.07.21 for (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 08 Mar 2022 16:07:21 -0800 (PST) Received: by mail-ej1-f54.google.com with SMTP id qt6so1348859ejb.11 for ; Tue, 08 Mar 2022 16:07:21 -0800 (PST) X-Received: by 2002:a05:6512:3049:b0:447:d55d:4798 with SMTP id b9-20020a056512304900b00447d55d4798mr12256093lfb.531.1646784431050; Tue, 08 Mar 2022 16:07:11 -0800 (PST) MIME-Version: 1.0 References: <20220308234723.3834941-1-yuzhao@google.com> In-Reply-To: <20220308234723.3834941-1-yuzhao@google.com> From: Linus Torvalds Date: Tue, 8 Mar 2022 16:06:54 -0800 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v8 00/14] Multi-Gen LRU Framework To: Yu Zhao Cc: Andrew Morton , Andi Kleen , Aneesh Kumar , Catalin Marinas , Dave Hansen , Hillf Danton , Jens Axboe , Jesse Barnes , Johannes Weiner , Jonathan Corbet , Matthew Wilcox , Mel Gorman , Michael Larabel , Michal Hocko , Mike Rapoport , Rik van Riel , Vlastimil Babka , Will Deacon , Ying Huang , Linux ARM , "open list:DOCUMENTATION" , Linux Kernel Mailing List , Linux-MM , page-reclaim@google.com, "the arch/x86 maintainers" Content-Type: text/plain; charset="UTF-8" X-Rspam-User: X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 72C9B4000D X-Stat-Signature: zneamgqemxbgqgybpkg5nw4ygwooiiwy Authentication-Results: imf17.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=google header.b="gOPY1r/w"; dmarc=none; spf=pass (imf17.hostedemail.com: domain of torvalds@linuxfoundation.org designates 209.85.218.45 as permitted sender) smtp.mailfrom=torvalds@linuxfoundation.org X-HE-Tag: 1646784443-252467 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Tue, Mar 8, 2022 at 3:48 PM Yu Zhao wrote: > > The current page reclaim is too expensive in terms of CPU usage and it > often makes poor choices about what to evict. This patchset offers an > alternative solution that is performant, versatile and > straightforward. So apart from my complaints about asking users config questions that simply should not be asked, I really think this just needs to start getting merged. We've seen several numbers on the upsides, and I don't think we'll see any of the downsides until we try it. And I don't think there is any question that we _shouldn't_ try it, given the numbers posted. But yeah, I certainly _hope_ that all the benchmarking has been done with a unified set of config values, and it's not some kind of bogus "cherry-picked config values for this particular machine" kind of benchmarking that has been done. Because that isn't valid benchmarking - comparing some "tuned for this paeticular machine or load" setup to a default one is just not worth even setting numbers to, and debases the whole value of posting results. Linus