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=-11.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 2ABC9C2D0A3 for ; Fri, 6 Nov 2020 18:45:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C6FF220702 for ; Fri, 6 Nov 2020 18:45:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727913AbgKFSp3 (ORCPT ); Fri, 6 Nov 2020 13:45:29 -0500 Received: from mga17.intel.com ([192.55.52.151]:26534 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726447AbgKFSp2 (ORCPT ); Fri, 6 Nov 2020 13:45:28 -0500 IronPort-SDR: 5IXlAbHAUTb6pupS2Qc0tQ4+9BJiDYqHdLwlQ9GbWbCDHH26CF6oHvyc97AQnsZuIaQaKQ9Kd3 lS0ibF7TfkOg== X-IronPort-AV: E=McAfee;i="6000,8403,9797"; a="149436831" X-IronPort-AV: E=Sophos;i="5.77,457,1596524400"; d="scan'208";a="149436831" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga004.jf.intel.com ([10.7.209.38]) by fmsmga107.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Nov 2020 10:45:28 -0800 IronPort-SDR: 2iS/yPM6+M8YUrWI+2wYcNHSBNl4MOQKDC6h4rjeaK92UuqlL/gAeFhuAn6icUOPyiLObxGuw4 rrwJCJUQU5Gw== X-IronPort-AV: E=Sophos;i="5.77,457,1596524400"; d="scan'208";a="472159885" Received: from iweiny-desk2.sc.intel.com (HELO localhost) ([10.3.52.147]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 06 Nov 2020 10:45:27 -0800 Date: Fri, 6 Nov 2020 10:45:27 -0800 From: Ira Weiny To: Alex Shi Cc: hannes@cmpxchg.org, akpm@linux-foundation.org, Michal Hocko , Vladimir Davydov , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/memcg: update page struct member in comments Message-ID: <20201106184527.GD3976735@iweiny-DESK2.sc.intel.com> References: <1604662413-5734-1-git-send-email-alex.shi@linux.alibaba.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1604662413-5734-1-git-send-email-alex.shi@linux.alibaba.com> User-Agent: Mutt/1.11.1 (2018-12-01) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Nov 06, 2020 at 07:33:33PM +0800, Alex Shi wrote: > The page->mem_cgroup member is replaced by memcg_data, and add a helper > page_memcg() for it. Need to update comments to avoid confusing. I'm not an expert in this code but IMO the pointer manipulation of page->mem_cgroup could be thought of as local to the code in mm/memcontrol.c. As such the detail of the member of the page struct that the code depends on is a valuable part of the comment. Having to look at page_memcg() to find out this information is kind of annoying. Ira > > Signed-off-by: Alex Shi > Cc: Johannes Weiner > Cc: Michal Hocko > Cc: Vladimir Davydov > Cc: Andrew Morton > Cc: cgroups@vger.kernel.org > Cc: linux-mm@kvack.org > Cc: linux-kernel@vger.kernel.org > --- > mm/memcontrol.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/mm/memcontrol.c b/mm/memcontrol.c > index b2aa3b73ab82..8a8debea34fc 100644 > --- a/mm/memcontrol.c > +++ b/mm/memcontrol.c > @@ -1310,7 +1310,7 @@ int mem_cgroup_scan_tasks(struct mem_cgroup *memcg, > * @page: the page > * @pgdat: pgdat of the page > * > - * This function relies on page->mem_cgroup being stable - see the > + * This function relies on page_memcg(page) being stable - see the > * access rules in commit_charge(). > */ > struct lruvec *mem_cgroup_page_lruvec(struct page *page, struct pglist_data *pgdat) > @@ -2862,7 +2862,7 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg) > { > VM_BUG_ON_PAGE(page_memcg(page), page); > /* > - * Any of the following ensures page->mem_cgroup stability: > + * Any of the following ensures page_memcg(page) stability: > * > * - the page lock > * - LRU isolation > -- > 1.8.3.1 >