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 CC860C4338F for ; Sun, 22 Aug 2021 09:46:24 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 55ADD61261 for ; Sun, 22 Aug 2021 09:46:24 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 55ADD61261 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id D1D2B8D0001; Sun, 22 Aug 2021 05:46:23 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CCD7A6B0072; Sun, 22 Aug 2021 05:46:23 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id BBBA98D0001; Sun, 22 Aug 2021 05:46:23 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0112.hostedemail.com [216.40.44.112]) by kanga.kvack.org (Postfix) with ESMTP id A0D826B006C for ; Sun, 22 Aug 2021 05:46:23 -0400 (EDT) Received: from smtpin06.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 28CDD82499A8 for ; Sun, 22 Aug 2021 09:46:23 +0000 (UTC) X-FDA: 78502236246.06.21C4B97 Received: from mail-ej1-f53.google.com (mail-ej1-f53.google.com [209.85.218.53]) by imf01.hostedemail.com (Postfix) with ESMTP id E088C501826A for ; Sun, 22 Aug 2021 09:46:22 +0000 (UTC) Received: by mail-ej1-f53.google.com with SMTP id a25so3459949ejv.6 for ; Sun, 22 Aug 2021 02:46:22 -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=kiiWJuV8Nn7XaXtzn9v3g/g55oYVXRF7bFW1eNMuWqD7BbxlsoaIL2v0PQKP3TO77j L6pNqOCIYpw1z9yLgR2hlBhK7er+9ZKTMzk300E0Xfq6CRLHpwcU+E2vyhSgcHUX4OAj B6b+jWghp4Ateu/cqE+zm+kKVL5d40FJ5iH/lbn7LJjde+N9nPKpdi4EhF0z1ByDx0Q4 DIOHSoM+DIR3OwvHkDccLDYS18BG+NtNtDDs7qC1ht+zexK4z+I4XP0WazUI/B8TI6jN pjWXP0Xf1IcBNXbBhemz/XNBaId2MdOCmjiP0gSzvPzZAQpHNwDhZGYy3lezYVgj/iyc tMqw== X-Gm-Message-State: AOAM532n/8SKfb+1b8wfGXrG73n8fctG0P88IysoikyZpWI9FndOy+Vk fqqyEZ2aoOqxN7VlNlno87eipFM3Y1/ZV/EOvSo= 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" Authentication-Results: imf01.hostedemail.com; dkim=pass header.d=gmail.com header.s=20161025 header.b=fc7l3zQQ; spf=pass (imf01.hostedemail.com: domain of yongwpur@gmail.com designates 209.85.218.53 as permitted sender) smtp.mailfrom=yongwpur@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: E088C501826A X-Stat-Signature: rz7fk6fpgumhcf5guo84d8i3i45h781g X-HE-Tag: 1629625582-932316 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: > 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.