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=-18.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_IN_DEF_DKIM_WL autolearn=ham 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 D2679C433E0 for ; Wed, 10 Feb 2021 13:47:05 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6256764E16 for ; Wed, 10 Feb 2021 13:47:05 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 6256764E16 Authentication-Results: mail.kernel.org; dmarc=fail (p=reject dis=none) header.from=google.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id E841A6B0075; Wed, 10 Feb 2021 08:47:04 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id E36056B0078; Wed, 10 Feb 2021 08:47:04 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D25086B007B; Wed, 10 Feb 2021 08:47:04 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0234.hostedemail.com [216.40.44.234]) by kanga.kvack.org (Postfix) with ESMTP id BC1FF6B0075 for ; Wed, 10 Feb 2021 08:47:04 -0500 (EST) Received: from smtpin10.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 898DE16954 for ; Wed, 10 Feb 2021 13:47:04 +0000 (UTC) X-FDA: 77802484368.10.snake70_3c09fbd27610 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin10.hostedemail.com (Postfix) with ESMTP id 697831698F9 for ; Wed, 10 Feb 2021 13:47:04 +0000 (UTC) X-HE-Tag: snake70_3c09fbd27610 X-Filterd-Recvd-Size: 3630 Received: from mail-lf1-f44.google.com (mail-lf1-f44.google.com [209.85.167.44]) by imf34.hostedemail.com (Postfix) with ESMTP for ; Wed, 10 Feb 2021 13:47:03 +0000 (UTC) Received: by mail-lf1-f44.google.com with SMTP id h26so2998974lfm.1 for ; Wed, 10 Feb 2021 05:47:03 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=x7AQuIHqlGeDKdDmQaoPxTGljXqoMuKxFCh/+vT0i5k=; b=nOGKWwErjCXi0YFKi585FYnDqp7VZktLvttuvqdhK0nRwzl46aW1e6ZK2y4GhoJ9i8 KpIxBAdYnb+08xigU5i30VZuFTrxH9hEDGhvwYEsy/vXJ20y3z8qmZGxB570y+8nwDXr KqRlvpUxKhal/kP45OJ60gFtDUeeffZe8T1LC5rRY+O2Fx+sJ5NgQqI1K5vhBdjd2A6B qJw8QKEDXZMZlFJvt+pc5moGlNUZkY9BSRYZmVwipRgXbnYqLGFJEc+CMn2+gVC3m7gE 4OfOhMBxuIem8mVWHVp+YR/xI5Pyv3MgEexPFS4XvAKqbFwqVEoJy6zxsM+1KZMJkXNM BJVw== 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=x7AQuIHqlGeDKdDmQaoPxTGljXqoMuKxFCh/+vT0i5k=; b=jxMA7zDKoD09hl503X//otXa3Z3Yd2IM6A3bkIyQt+v84xryVHaTFsSzgOVGjPwpHo LXX+IEYbpddC6WjrhlLA8l4oqf9VNU4ZrpZzrKY/y0ajLzjtM5XYcF87/xmHMJxMbVvZ 39GkIj/u1Z5Eu7Ch4vQm5ilO71hl+VWo2tz56DpZO1EwS4jmXoUozWgkGEZsKQ06B0fK CL+pvAQNG5FMRlKwt7gH+NC1YPBvBSfEwpQpnAo3MOd8JoEmNo2ZIzaldaJAOaRY9O9n /by5FX0f1CjGg25NubXbyqPvdNgH96F37CiaPAPFHSnZsEVw6bxmjB8sOaS3eEK0pGK3 q5aA== X-Gm-Message-State: AOAM531QRngth4DJaZZqhZ65K3lXdLP65z4TBQ8CPk6qu++eejUfUtzk h3yqPXJO3G8Oemr8Q616+C4dK7BZ7raC3b9dOwlmTw== X-Google-Smtp-Source: ABdhPJz841Cfn+4sq64Q5uE+gYJv38/kovaen61M8ii6Y201iSug/qJh/kkiv/4ACj5E6wmRFUhiWf/OXsFV7bvBq+s= X-Received: by 2002:a05:6512:6c6:: with SMTP id u6mr1722867lff.347.1612964822071; Wed, 10 Feb 2021 05:47:02 -0800 (PST) MIME-Version: 1.0 References: <20210209214543.112655-1-hannes@cmpxchg.org> In-Reply-To: <20210209214543.112655-1-hannes@cmpxchg.org> From: Shakeel Butt Date: Wed, 10 Feb 2021 05:46:51 -0800 Message-ID: Subject: Re: [PATCH] mm: page-writeback: simplify memcg handling in test_clear_page_writeback() To: Johannes Weiner Cc: Andrew Morton , Hugh Dickins , Michal Hocko , Roman Gushchin , Linux MM , Cgroups , LKML , Kernel Team 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 Tue, Feb 9, 2021 at 1:45 PM Johannes Weiner wrote: > > Page writeback doesn't hold a page reference, which allows truncate to > free a page the second PageWriteback is cleared. This used to require > special attention in test_clear_page_writeback(), where we had to be > careful not to rely on the unstable page->memcg binding and look up > all the necessary information before clearing the writeback flag. > > Since commit 073861ed77b6 ("mm: fix VM_BUG_ON(PageTail) and > BUG_ON(PageWriteback)") test_clear_page_writeback() is called with an > explicit reference on the page, and this dance is no longer needed. > > Use unlock_page_memcg() and dec_lruvec_page_stat() directly. > > Signed-off-by: Johannes Weiner Reviewed-by: Shakeel Butt