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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 A4F02C4338F for ; Sun, 22 Aug 2021 09:46:28 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8703761262 for ; Sun, 22 Aug 2021 09:46:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233102AbhHVJrF (ORCPT ); Sun, 22 Aug 2021 05:47:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41250 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229719AbhHVJrE (ORCPT ); Sun, 22 Aug 2021 05:47:04 -0400 Received: from mail-ej1-x62f.google.com (mail-ej1-x62f.google.com [IPv6:2a00:1450:4864:20::62f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5343DC061575; Sun, 22 Aug 2021 02:46:23 -0700 (PDT) Received: by mail-ej1-x62f.google.com with SMTP id me10so1789047ejb.11; Sun, 22 Aug 2021 02:46:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=0e3vNQgHPFxuVsKWr/oiMNC9HxWPWcJlOWQMgnCyZR0=; b=fc7l3zQQBiTvLtZ8kw7ugWuyAEkBM9yOfrxUda3mcyP2YOK/iuevz3ldkBdbTGAFLR NjU2QWLhmeb4es1ZtlCij3Ejl4pkK4OIqFC1XRUgurK338ndY3KSx9Ql/OZeNNPQ0LRs srT8tXDwVj5+QHv0uUcPx9Vn7se2owBwg+f4hXjPxOx9gKWu8t7LY/ycUcicpxdPei5r VKO9/Qm5WAZshb3BK5bPL2m6uAtiVFURCJ5iD97XSPCW2mc1sai0KIr3XVgvPUzeBCFB Gblig3buVPTC0GFSM7kZXGvulIrou6p8bsvPfTNH9k/SwYk/E6YhPasCoj9jpPr6utP+ T09g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=0e3vNQgHPFxuVsKWr/oiMNC9HxWPWcJlOWQMgnCyZR0=; b=Lwq1cBWK3A9ne2VfTtbbxHT2L/bTtG7k+CLNHH+9+Re1gp75b3YOuAmhvK/JuzBOai b+u3CYcaItxUPlK8cCoz+WlFPbgWgEdMV/XEFQQV3IS4Z0jw2syALoixO5BHNVrkPeV+ aW+Y8LAy0laOWNoPqyhGzE0QTVS9U1l21mwYzxkMVERW/lIxVOlXo6M+eW7Vw0B/NaVc sYUYuwEBm+iEFzVv1TOU0Ln+Nf3mMrAMiWVBOo7x5tuI+IkN1iJIGhi1XAO/HcmqMydm pzjJLDBGx7FbhTsqyq+RkazdZGFONpV8gaDnHiLLudiDanDT7OGigK6u+agE6WKhSrSB Lrdg== X-Gm-Message-State: AOAM532HelauJyv3sG32qQz2hqNlY0XGJ0K0kHpSRPq7u4cu+k7usPaZ 0J5GfsDhYiMkJ2O7en8oOlkA4g4TYl74jqQnhto= X-Google-Smtp-Source: ABdhPJxVfiwhlP4JKkL/U2DXMsUbZPLWOJO1lrKtf4l/kc1VMF0+3F69CLJDWAl1TEhXs1BicZrGGWQtMPGdL+zUMr8= X-Received: by 2002:a17:906:a18b:: with SMTP id s11mr30974716ejy.8.1629625581682; Sun, 22 Aug 2021 02:46:21 -0700 (PDT) MIME-Version: 1.0 References: <1629417219-74853-1-git-send-email-wang.yong12@zte.com.cn> In-Reply-To: From: yong w Date: Sun, 22 Aug 2021 17:46:08 +0800 Message-ID: Subject: Re: [PATCH v2] mm: Add configuration to control whether vmpressure notifier is enabled To: Michal Hocko Cc: Tejun Heo , Jonathan Corbet , Andrew Morton , Vladimir Davydov , Thomas Gleixner , "Peter Zijlstra (Intel)" , Shakeel Butt , Roman Gushchin , alexs@kernel.org, Wei Yang , Hui Su , Stephen Rothwell , wang.yong12@zte.com.cn, Cgroups , linux-doc@vger.kernel.org, LKML , Linux MM , yang.yang29@zte.com.cn Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > All those reasons should be a part of the changelog. >.... > I am not sure these are sufficient justifications but that is something > to discuss. And hence it should be a part of the changelog. > OK, These reasons will be added to the patch notesin later versions. > > 3. In the case where the user does not need vmpressure, vmpressure > > calculation is additional overhead. > > You should quantify that and argue why that overhead cannot be further > reduced without config/boot time knobs. > The test results of the previously used PFT tool may not be obvious. Is there a better way to quantify it? > > In some special scenes with tight memory, vmpressure will be executed > > frequently.we use "likely" and "inline" > > to improve the performance of the kernel, why not reduce some > > unnecessary calculations? > > I am all for improving the code. Is it possible to do it by other means? > E.g. reduce a potential overhead when there no events registered? Yes, the method you mentioned may be feasible, but it does not conflict with this patch. Thanks.