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=-8.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 90616C433E0 for ; Thu, 18 Mar 2021 15:10:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5B38064F18 for ; Thu, 18 Mar 2021 15:10:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231630AbhCRPJx (ORCPT ); Thu, 18 Mar 2021 11:09:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35016 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231739AbhCRPJa (ORCPT ); Thu, 18 Mar 2021 11:09:30 -0400 Received: from mail-qt1-x82d.google.com (mail-qt1-x82d.google.com [IPv6:2607:f8b0:4864:20::82d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE310C06174A for ; Thu, 18 Mar 2021 08:09:29 -0700 (PDT) Received: by mail-qt1-x82d.google.com with SMTP id l13so4278613qtu.9 for ; Thu, 18 Mar 2021 08:09:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cmpxchg-org.20150623.gappssmtp.com; s=20150623; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=LmVYj5GvufpNSkWZh3TqEcOCWKFGXIRDgIsopg1YFuM=; b=ulrGxS7Qh+EZB3EC7EZ6XWGF9uV+2Im5DF6vdI74sxHXQ7+LAUp3Z9fzI4t4hOPLu1 EKGkNt3scr4mGD6IiYO0ph/t84ASN6ObxjhKuvALGQkzndEDQVOVRA6n2Ij/UouVx/ri +D3vKXEuJb3QI+JbdIyikPHdHf2n/wqkyUD4PCx22vU58kiF+7Fl1a3zeyRthnDl9c/K NBQoQA5u9CJY8QHRTEjrP2xq2Jon32B8hVAHry6S36tx+L9G0lk0YgAXIlXBbzFjY93t flcnNyVaUsbDhufdpGvMgm7b+V6/Ccdx3/YFMT+iK0cB2i0ToQUBk0D4LN7/hgeeMSOb yzag== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=LmVYj5GvufpNSkWZh3TqEcOCWKFGXIRDgIsopg1YFuM=; b=IaYpn17KDoZkEMsuX4l5fEJPDSmnXuUTtIh3PnjDsveOeOQ807z7AUrtUV5eD5sLeq xtS8FgK65Vcl+Se4auHKWBDKmLtTJFwE7nYGklgQqxiCyqIYVuXT0YAO20VcwDF3jIqS tzauimtPXMG/88GwPAxpj8dsJ0eHlUx6PlJBYfkXGzI1wJUcF4PKKwg8Dn5qjlPunwfa SOg25qlXYzz4QUvBxNS9MfV1eVZ2Mg9IuQIPEwhwdoLTHwR8PqbZMbWtTrW3+Ad7CMDw cWDLvx6SWEtTuT++XV0a+v1J9yCxFkYA3rhuZSQqXdLZ2rBOXyfO4PMN9rEWWfP0rR/P JUZw== X-Gm-Message-State: AOAM530l3ij7Pmxse5kA1HpxH3YVIfbMNGu+9T1/QDK4W8tJOY1eQNGk 8y5glQ4p9joWaKuA3TDNM45MU3HfXWv/dQ== X-Google-Smtp-Source: ABdhPJxV+Rn2hqhytpbtN66foGM/tpwhN1aAFHOf77XeB9sQODc/ocrUa0o1hJszW1opYtM88D762w== X-Received: by 2002:ac8:520d:: with SMTP id r13mr4238983qtn.38.1616080168937; Thu, 18 Mar 2021 08:09:28 -0700 (PDT) Received: from localhost ([2620:10d:c091:480::1:e46c]) by smtp.gmail.com with ESMTPSA id d14sm1561517qtj.92.2021.03.18.08.09.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 18 Mar 2021 08:09:28 -0700 (PDT) Date: Thu, 18 Mar 2021 11:09:27 -0400 From: Johannes Weiner To: Muchun Song Cc: guro@fb.com, mhocko@kernel.org, akpm@linux-foundation.org, shakeelb@google.com, vdavydov.dev@gmail.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, duanxiongchun@bytedance.com Subject: Re: [PATCH v4 2/5] mm: memcontrol: directly access page->memcg_data in mm/page_alloc.c Message-ID: References: <20210318110658.60892-1-songmuchun@bytedance.com> <20210318110658.60892-3-songmuchun@bytedance.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210318110658.60892-3-songmuchun@bytedance.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 18, 2021 at 07:06:55PM +0800, Muchun Song wrote: > The page_memcg() is not suitable for use by page_expected_state() and > page_bad_reason(). Because it can BUG_ON() for the slab pages when > CONFIG_DEBUG_VM is enabled. As neither lru, nor kmem, nor slab page > should have anything left in there by the time the page is freed, what > we care about is whether the value of page->memcg_data is 0. So just > directly access page->memcg_data here. > > Signed-off-by: Muchun Song Acked-by: Johannes Weiner