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 68D62C433F5 for ; Fri, 8 Apr 2022 17:32:47 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id D06666B0072; Fri, 8 Apr 2022 13:32:46 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id CB55A6B0073; Fri, 8 Apr 2022 13:32:46 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id B7C866B0074; Fri, 8 Apr 2022 13:32:46 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0030.hostedemail.com [216.40.44.30]) by kanga.kvack.org (Postfix) with ESMTP id A63406B0072 for ; Fri, 8 Apr 2022 13:32:46 -0400 (EDT) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 5C1B98249980 for ; Fri, 8 Apr 2022 17:32:46 +0000 (UTC) X-FDA: 79334406732.31.E8AC26C Received: from mail-pj1-f48.google.com (mail-pj1-f48.google.com [209.85.216.48]) by imf02.hostedemail.com (Postfix) with ESMTP id F205080006 for ; Fri, 8 Apr 2022 17:32:45 +0000 (UTC) Received: by mail-pj1-f48.google.com with SMTP id o5-20020a17090ad20500b001ca8a1dc47aso12515009pju.1 for ; Fri, 08 Apr 2022 10:32:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=u+kUNyfJxKm1ujevbiKigyKUXoT0kLKRU8aUxaHDSJE=; b=LrDF39pFuyzFZCAc/KZZzv/i/lQS7AbtFvrZsJC9ht/xGzpR4Uap43EwOT5pCq/gN0 0m1zd3eKnI3N0ZqQP8BuVhki7pJYY6UMdIBH4phNgf8qTpH5VTEHtFOqCwsQwA62br0G Q1uJDMHB/x21RFxO+Z8hf6PAlMJkaWLmo/ZCnKot2lzGZ+MonvsIuMf8Z9zoOw2Gv1tg c4YlFWRUNBZyH2vdaEAEu/LKLWYOx2Rqw1i29D/YkmDw+0DTeSlquJ0xpHtTWLeW8uGL 7H+QtiemzbyiWRUSZz3F8a8DKxGLKb+OBTD3ZJq1ocgSbKbQ8ULO1gTGmuGEp7520Gmw O8lw== 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=u+kUNyfJxKm1ujevbiKigyKUXoT0kLKRU8aUxaHDSJE=; b=QmVYCZ2jj7WyCtPoKz7CA+DeXmJM4lY1SE2rfT+VsqpRjWgzCoqVRcP/N9A1Ska37+ OJs8TZqLBQBacrrvqs3Ax5vWwYYn+C8wTOh4W55MsznRmRhm5HsR8eHjihJqQEjgYDTz 0CUZM5rXE8bC5ismH8i3xzkn3rwH5Usjg1sn0fEG5mKYVHCM1Bu2GcG1d80A8s82GAqc RzraC/XYfP+6KjiZkZmNIfDaNwRZnb2bgIl2PqF9pkCRW0c98GJNoHzZOk7cdsdZSAqI DHiJljh0lKqbT2nz/aptGOL3HSP9LKnTgMYphWXu6Zd4Hsh2TL6ijn3WFZXc40wTS3zv aDBg== X-Gm-Message-State: AOAM532PoXOp4SQaDpBRNFb2/1pcO4dFBH0ev/ImPJOsJsnm2RgnFHAD S+iSj8KLtktocJGn34TWdG+XpJKYR8fuwybJw+A= X-Google-Smtp-Source: ABdhPJyo+7ur34lczUuWXhS+cFJV0p3jAE1QHpbJ+OGoe30mxQfN2d/8OcdiDpUhGPMbA6MKB7D70J3WbKtxfEf6ZFA= X-Received: by 2002:a17:902:9304:b0:155:eb5a:8dd4 with SMTP id bc4-20020a170902930400b00155eb5a8dd4mr20540077plb.117.1649439164974; Fri, 08 Apr 2022 10:32:44 -0700 (PDT) MIME-Version: 1.0 References: <20220407130352.15618-1-linmiaohe@huawei.com> <20220407130352.15618-2-linmiaohe@huawei.com> <09d363ba-5bd0-75ae-8ece-cd91997f1b46@redhat.com> In-Reply-To: <09d363ba-5bd0-75ae-8ece-cd91997f1b46@redhat.com> From: Yang Shi Date: Fri, 8 Apr 2022 10:32:33 -0700 Message-ID: Subject: Re: [PATCH 1/3] mm/memory-failure.c: avoid false-postive PageSwapCache test To: David Hildenbrand Cc: Miaohe Lin , Andrew Morton , =?UTF-8?B?SE9SSUdVQ0hJIE5BT1lBKOWggOWPoyDnm7TkuZ8p?= , Mike Kravetz , Linux MM , Linux Kernel Mailing List Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam09 X-Rspam-User: X-Stat-Signature: tmchhz589zi4eandq5sgaupgo9jgpsjb Authentication-Results: imf02.hostedemail.com; dkim=pass header.d=gmail.com header.s=20210112 header.b=LrDF39pF; dmarc=pass (policy=none) header.from=gmail.com; spf=pass (imf02.hostedemail.com: domain of shy828301@gmail.com designates 209.85.216.48 as permitted sender) smtp.mailfrom=shy828301@gmail.com X-Rspamd-Queue-Id: F205080006 X-HE-Tag: 1649439165-892799 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, Apr 8, 2022 at 1:52 AM David Hildenbrand wrote: > > On 07.04.22 15:03, Miaohe Lin wrote: > > PageSwapCache is only reliable when PageAnon is true because PG_swapcache > > serves as PG_owner_priv_1 which can be used by fs if it's pagecache page. > > So we should test PageAnon to distinguish pagecache page from swapcache > > page to avoid false-postive PageSwapCache test. > > Well, that's not quite correct. Just because a page is PageAnon() > doesn't mean that it's in the swapache. It means that it might be in the > swapcache but cannot be in the pagecache. > > Maybe you wanted to say > > "So we should test PageAnon() to distinguish pagecache pages from > anonymous pages." Yeah, I agree. The patch looks fine to me with David's comment addressed. > > > > > Signed-off-by: Miaohe Lin > > --- > > mm/memory-failure.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/mm/memory-failure.c b/mm/memory-failure.c > > index ef402b490663..2e97302d62e4 100644 > > --- a/mm/memory-failure.c > > +++ b/mm/memory-failure.c > > @@ -2262,7 +2262,7 @@ static int __soft_offline_page(struct page *page) > > return 0; > > } > > > > - if (!PageHuge(page) && PageLRU(page) && !PageSwapCache(page)) > > + if (!PageHuge(page) && PageLRU(page) && !PageAnon(page)) > > /* > > * Try to invalidate first. This should work for > > * non dirty unmapped page cache pages. > > > -- > Thanks, > > David / dhildenb > >