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=-3.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,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 09927C4361B for ; Fri, 4 Dec 2020 16:12:47 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 76DD222838 for ; Fri, 4 Dec 2020 16:12:46 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 76DD222838 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=bytedance.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id EBACB6B0074; Fri, 4 Dec 2020 11:12:45 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E6C6D6B0075; Fri, 4 Dec 2020 11:12:45 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D821D6B0078; Fri, 4 Dec 2020 11:12:45 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0059.hostedemail.com [216.40.44.59]) by kanga.kvack.org (Postfix) with ESMTP id C1A946B0074 for ; Fri, 4 Dec 2020 11:12:45 -0500 (EST) Received: from smtpin01.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 868118249980 for ; Fri, 4 Dec 2020 16:12:45 +0000 (UTC) X-FDA: 77556093090.01.beds58_2206635273c5 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin01.hostedemail.com (Postfix) with ESMTP id 21D5610047F6C for ; Fri, 4 Dec 2020 16:12:45 +0000 (UTC) X-HE-Tag: beds58_2206635273c5 X-Filterd-Recvd-Size: 3772 Received: from mail-pl1-f194.google.com (mail-pl1-f194.google.com [209.85.214.194]) by imf26.hostedemail.com (Postfix) with ESMTP for ; Fri, 4 Dec 2020 16:12:44 +0000 (UTC) Received: by mail-pl1-f194.google.com with SMTP id b23so3344264pls.11 for ; Fri, 04 Dec 2020 08:12:43 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance-com.20150623.gappssmtp.com; s=20150623; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=vgBK6gNRJdzBFc9vMwzbFn3dmf1hBTZHlv0OSygLjJk=; b=1sagrwP/FVGDih5ebdMkoXfp/7l+m3CFyw+VwGe6s7hnyBJkj1OCbcWJs6EQsuZbeB pbHStSPO2i64md/0IbNCHlRzcvz2brcSwdXUY6LkN1Br6xwtHiyZTxv3oZxLMrr4kUAA 9GsOrYKHTekTKILQANM/eemKSkFbE9yb9RsstW9j+OBdmwN5u0Jvy6O20AEPihKsHnHA kgxlgBqci7fjgnksBtC1/YOF9g2Sv29hm3SeZBNhclmAL0cphUigc/ukjcXRZr4WRXj7 TqDDUl9C5AHrsBguZ1iyzIwBA/xjmRlytmybQVNMd4m76hwTYsUljwnsq6EMrbjqSH99 3p+g== 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=vgBK6gNRJdzBFc9vMwzbFn3dmf1hBTZHlv0OSygLjJk=; b=s9rGmL6N3g1x6R+shYtrhGzMGqlAfVqoGlEicMSWCnoQk0QR/jIbyMw+aHj1zj16Na vDjqVgH60y3cDSrY+y/9HNevoGkOl/vPM76lX4pujofwn9oFei/sboKOCDs1cPxfFZam Db7pCdi25B1Qiz6hb0Fy7uEsql0wCTTF1SSsgy+W6KpZGIsfiDyGp1/RkJzeByhBw9SN mpuZgMjtpUuBHecNPj1KdIy/1G9UZ1/1VgtlVkjfPZ6yOlMpmFBsdPit0Y2d9YEWywZQ IfdRsYix2A+6971gEgbdjTs5ewaHBv7FL8ZeajtVaev7UuvBoj9u+EN70lxg+Ls6Z/YV 1cRA== X-Gm-Message-State: AOAM530UVwpVWYbTEZy/a1zMrmzl8/nQS3rYhqr77mvoqEdVqQQ1UCDX F3eK0I/G00Qq3BLNkQe5cA5fHMhZAIfwpOAuWajnuQ== X-Google-Smtp-Source: ABdhPJyLaDNma2sWdL6BfboS+XrP7SCgS1iMGsBIQVI6ZPAsifoMRSkbIa0G9agbEQiwezzKGGDL5d1+GQRQWOJdQjQ= X-Received: by 2002:a17:902:76c8:b029:d9:d6c3:357d with SMTP id j8-20020a17090276c8b02900d9d6c3357dmr4605653plt.34.1607098363125; Fri, 04 Dec 2020 08:12:43 -0800 (PST) MIME-Version: 1.0 References: <20201203162237.21885-1-songmuchun@bytedance.com> <46fcf0c1-7c38-723b-8905-953d72f1d6bc@redhat.com> In-Reply-To: <46fcf0c1-7c38-723b-8905-953d72f1d6bc@redhat.com> From: Muchun Song Date: Sat, 5 Dec 2020 00:12:06 +0800 Message-ID: Subject: Re: [External] Re: [PATCH v2] mm/page_isolation: do not isolate the max order page To: David Hildenbrand Cc: Andrew Morton , Linux Memory Management List , LKML , Vlastimil Babka Content-Type: text/plain; charset="UTF-8" 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 Fri, Dec 4, 2020 at 12:28 AM David Hildenbrand wrote: > > On 03.12.20 17:22, Muchun Song wrote: > > The max order page has no buddy page and never merge to other order. > > So isolating and then freeing it is pointless. And if order == MAX_ORDER > > - 1, then the buddy can actually be a !pfn_valid() in some corner case? > > pfn_valid_within(buddy_pfn) that follows would only catch it on archs > > with holes in zone. Then is_migrate_isolate_page(buddy) might access an > > invalid buddy. So this is also a bug fix. > > > > Fixes: 3c605096d315 ("mm/page_alloc: restrict max order of merging on isolated pageblock") > > As just replied to v1, I don't think this is required and the patch You mean we should remove the Fixes tag? Thanks. > description can be simplified - e.g., stating that we have/had not such > users. > > > -- > Thanks, > > David / dhildenb > -- Yours, Muchun