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 A8A6EC433F5 for ; Wed, 9 Mar 2022 00:15:05 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C44CB8D0002; Tue, 8 Mar 2022 19:15:04 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id BCD278D0001; Tue, 8 Mar 2022 19:15:04 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A1FD48D0002; Tue, 8 Mar 2022 19:15:04 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0185.hostedemail.com [216.40.44.185]) by kanga.kvack.org (Postfix) with ESMTP id 8BCBD8D0001 for ; Tue, 8 Mar 2022 19:15:04 -0500 (EST) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 45716A8329 for ; Wed, 9 Mar 2022 00:15:04 +0000 (UTC) X-FDA: 79222927728.31.164AD9E Received: from mail-vk1-f180.google.com (mail-vk1-f180.google.com [209.85.221.180]) by imf28.hostedemail.com (Postfix) with ESMTP id C2EBBC000C for ; Wed, 9 Mar 2022 00:15:03 +0000 (UTC) Received: by mail-vk1-f180.google.com with SMTP id c4so428811vkq.9 for ; Tue, 08 Mar 2022 16:15:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=C9mwhzMPXsuBhWeNQaY1yLcs8fwNMTqk4ERNtUz41w0=; b=BDABS9uVQcFS/djzmKr84X48kvQ7FDJAHE5GyVdrdiXPfTAYC3kgAFEzfvB6h5+7Ne DKI04IYSdFHK205mfzwOunyx4PHkbqy5VyoQ+nymhIwFfW7fLx6kcpzrepYQtmDNfncI YRhh6zrCf45T/6Th5xWqyvHHaC1k7FaJUXexXtRN4AiXd2xH+N4D4P3m+p/ADG+Xg6ve AFjeP6Jm272NK/5u/t9B1O8Qh2xSavwE4p9U+Dr8Oiwr+ilU5lrCUw3f+pMoIIM882Va O0xSq8iwXs3eCyKaIJHJymhVdMnlCnaqFoNkx7QlKg6nFd850+5Z0Y1pVrPq8DGUnblw V87g== 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=C9mwhzMPXsuBhWeNQaY1yLcs8fwNMTqk4ERNtUz41w0=; b=pAUXdP0yN4HwWRWBPCPvH1FgtVPM/aUfKyghdICPn+w0y/PYRB0vHgtxmcVp+6tv1Z LX1iNqmxaUI3flNnMeN3/sUPL4hcwerG7AhCWEAt8OxqTvvpR0y2gTQkfv6xqDwwI65q rQ0EwinH/pzFVK8Mrv+qifhjWyowQvzL4/dnyR4siID4HA8yPjuJov+63P9Np9GIRuTT om4zRI20GZf8UkX8PfzMMidpVe7UBTNA7VhyCWZo+jiW0IkMdUHSLdKGUC86mOukhmSi 88gD7zdjKWIMp9ghMVgdDur3gdQMDZEzKjCg2/g2HqgqL6Joegl6TG9IVX2xVXQ1jxR9 umfQ== X-Gm-Message-State: AOAM530GXI+9NN0hl3yds7ReihtOTObKQZq8+QIRRuj+kYKFCMmtpjv3 mBYVLoqfhRxDjQPcDXCvM3v2HoI3Cl4JHPlOYiE2SA== X-Google-Smtp-Source: ABdhPJyBAfeSZLyjOQmRLVwYDPtCASEbExuTxYgwggPQnIDguzuOxXWN2t0qp9chTtu67kkdtr9sUGRdA8hf3NSsJIk= X-Received: by 2002:a1f:314b:0:b0:331:fff6:a89e with SMTP id x72-20020a1f314b000000b00331fff6a89emr8182208vkx.26.1646784902851; Tue, 08 Mar 2022 16:15:02 -0800 (PST) MIME-Version: 1.0 References: <20220308234723.3834941-1-yuzhao@google.com> In-Reply-To: From: Yu Zhao Date: Tue, 8 Mar 2022 17:14:51 -0700 Message-ID: Subject: Re: [PATCH v8 00/14] Multi-Gen LRU Framework To: Linus Torvalds 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 , Kernel Page Reclaim v2 , "the arch/x86 maintainers" Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam05 X-Rspamd-Queue-Id: C2EBBC000C X-Rspam-User: Authentication-Results: imf28.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=BDABS9uV; spf=pass (imf28.hostedemail.com: domain of yuzhao@google.com designates 209.85.221.180 as permitted sender) smtp.mailfrom=yuzhao@google.com; dmarc=pass (policy=reject) header.from=google.com X-Stat-Signature: xyhyjdqt57utpycsb316kon556gmx664 X-HE-Tag: 1646784903-276008 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 5:07 PM Linus Torvalds wrote: > > 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. All benchmarks were done with the default config values. I'm removing those config options now. This sounds self-serving: our data centers want them, so I had to try.