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 35D3DC433EF for ; Thu, 3 Mar 2022 02:15:16 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id B8F108D0002; Wed, 2 Mar 2022 21:15:15 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B16A98D0001; Wed, 2 Mar 2022 21:15:15 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9B8048D0002; Wed, 2 Mar 2022 21:15:15 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0164.hostedemail.com [216.40.44.164]) by kanga.kvack.org (Postfix) with ESMTP id 866DC8D0001 for ; Wed, 2 Mar 2022 21:15:15 -0500 (EST) Received: from smtpin18.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id 445F9181CC1A5 for ; Thu, 3 Mar 2022 02:15:15 +0000 (UTC) X-FDA: 79201457790.18.2CB3840 Received: from mail-vk1-f173.google.com (mail-vk1-f173.google.com [209.85.221.173]) by imf21.hostedemail.com (Postfix) with ESMTP id CEA5A1C000A for ; Thu, 3 Mar 2022 02:15:14 +0000 (UTC) Received: by mail-vk1-f173.google.com with SMTP id j9so1938692vkj.1 for ; Wed, 02 Mar 2022 18:15:14 -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=gdhuskQuosfzBeb8z+Fw+9uS9iR9qqjZkm3VJwDCg1o=; b=fyifej2r6yEl56R5HvkqsbKCxJQYs3JnwGY15Xz9Yg5jb5u4KHiFnxV74A7BjArKsi n+CL7ALafiR7YROr6a3DxuvZtTGr9JtxncoklQYbZi6KeHDXJHUxuOXv6et67gkrFE/z vNcIJjpc+iZEvm6Es8oGzg+MXqI6qJgb1XLwi1pzZQgx10b9ExJhVwj38dRUi5T8y53M MxuLimBtNYj5w+JfnyL9kpEPuT2BFaCwbEnimlXbh8BubzixXIrrJ2MI8r/14cavKxyp jY0XilCRm/PAjuCgIwcVGhzHucwrgs7eV56+QLr91cQC+tY2I+B+kaE7MReEe99TixCy A4Lg== 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=gdhuskQuosfzBeb8z+Fw+9uS9iR9qqjZkm3VJwDCg1o=; b=pP/2Ow+gSq/3hvByQawyFLVQVLwqET2lszyiy8pko61x+4IQk0u66RxMDTLPysibb+ C3LPdcsM63GTByQGW18K31e1+ts7S6EfVygIHnj51o8xfEm0ZjjHJe/0kFUM0Hnq/MvV VAs9QBJqYKirvBT2ei/nSmDwE5i6aGn0EA546gHbKQ8XTR1anrXQzd6D/HuuRMy/infW kBq/doxchwMfnwwIuv5Q6Z8yvT3Fit3ldktvD5Map5ds46tLuh3NvyJ13eCMvrS5ElVO +mzol33UdSS53Ep7zN6r7m0eqWmemRgJB9ykU/D9anFuKNW9ihmuWT5CNQPLF6g6KBlJ qa1w== X-Gm-Message-State: AOAM5328d/8ny3QLp9uWEonPDpr/CTnoEss8CSe6H4k4t75t67G9FKEw bamqPHrdt+o31Y1qjbHmTbEvAwMqCAj5qeJF1C6Rww== X-Google-Smtp-Source: ABdhPJxxPJmUqV3N42adKjLUQWTJARjhYVZ1C1A4KeWxCTKz/K1bi7A7Qb8l8sGihbUQCrrlqH0Q9z+ocAsnCEpRYPk= X-Received: by 2002:a05:6122:208c:b0:320:3628:10be with SMTP id i12-20020a056122208c00b00320362810bemr13545734vkd.14.1646273713966; Wed, 02 Mar 2022 18:15:13 -0800 (PST) MIME-Version: 1.0 References: <351df0af-78f2-c20-2a6d-e5f978e5ca1@google.com> In-Reply-To: <351df0af-78f2-c20-2a6d-e5f978e5ca1@google.com> From: Yu Zhao Date: Wed, 2 Mar 2022 19:15:02 -0700 Message-ID: Subject: Re: [PATCH mmotm] mm: delete __ClearPageWaiters() To: Hugh Dickins Cc: Andrew Morton , Matthew Wilcox , Nicholas Piggin , Yang Shi , Michal Hocko , linux-kernel , Linux-MM Content-Type: text/plain; charset="UTF-8" X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: CEA5A1C000A X-Rspam-User: Authentication-Results: imf21.hostedemail.com; dkim=pass header.d=google.com header.s=20210112 header.b=fyifej2r; dmarc=pass (policy=reject) header.from=google.com; spf=pass (imf21.hostedemail.com: domain of yuzhao@google.com designates 209.85.221.173 as permitted sender) smtp.mailfrom=yuzhao@google.com X-Stat-Signature: pddk98z84qjgz6ua3epfu6jt4be64sqw X-HE-Tag: 1646273714-833473 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 Wed, Mar 2, 2022 at 6:56 PM Hugh Dickins wrote: > > The PG_waiters bit is not included in PAGE_FLAGS_CHECK_AT_FREE, and > vmscan.c's free_unref_page_list() callers rely on that not to generate > bad_page() alerts. So __page_cache_release() and release_pages() (and > the presumably copy-and-pasted put_zone_device_private_or_public_page()) > are redundant and misleading to make a special point of clearing it (as > the "__" implies, it could only safely be used on the freeing path). > > Delete __ClearPageWaiters(). Remark on this in one of the "possible" > comments in wake_up_page_bit(), and delete the superfluous comments. > > Signed-off-by: Hugh Dickins > --- > We've used this since 2018, and I see Yu Zhao posted similar in 2020: > https://lore.kernel.org/linux-mm/20200818184704.3625199-3-yuzhao@google.com/ > I couldn't join in at that time, but think its reception was over-cautious. Indeed. Tested-by: Yu Zhao