From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f52.google.com (mail-wm0-f52.google.com [74.125.82.52]) by kanga.kvack.org (Postfix) with ESMTP id 3A0166B0009 for ; Wed, 2 Mar 2016 11:44:21 -0500 (EST) Received: by mail-wm0-f52.google.com with SMTP id l68so88601744wml.0 for ; Wed, 02 Mar 2016 08:44:21 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id y133si5761044wme.72.2016.03.02.08.44.19 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 02 Mar 2016 08:44:19 -0800 (PST) Subject: Re: [PATCH v4 1/2] mm: introduce page reference manipulation functions References: <1456448282-897-1-git-send-email-iamjoonsoo.kim@lge.com> From: Vlastimil Babka Message-ID: <56D71860.7050108@suse.cz> Date: Wed, 2 Mar 2016 17:44:16 +0100 MIME-Version: 1.0 In-Reply-To: <1456448282-897-1-git-send-email-iamjoonsoo.kim@lge.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: js1304@gmail.com, Andrew Morton Cc: Michal Nazarewicz , Minchan Kim , Mel Gorman , "Kirill A. Shutemov" , Sergey Senozhatsky , Steven Rostedt , linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-api@vger.kernel.org, Joonsoo Kim On 02/26/2016 01:58 AM, js1304@gmail.com wrote: > From: Joonsoo Kim > > Success of CMA allocation largely depends on success of migration > and key factor of it is page reference count. Until now, page reference > is manipulated by direct calling atomic functions so we cannot follow up > who and where manipulate it. Then, it is hard to find actual reason > of CMA allocation failure. CMA allocation should be guaranteed to succeed > so finding offending place is really important. > > In this patch, call sites where page reference is manipulated are converted > to introduced wrapper function. This is preparation step to add tracepoint > to each page reference manipulation function. With this facility, we can > easily find reason of CMA allocation failure. There is no functional change > in this patch. > > In addition, this patch also converts reference read sites. It will help > a second step that renames page._count to something else and prevents later > attempt to direct access to it (Suggested by Andrew). > > Acked-by: Michal Nazarewicz > Signed-off-by: Joonsoo Kim Even without Patch 2/2 this is a nice improvement. Acked-by: Vlastimil Babka Although somebody might be confused by page_ref_count() vs page_count(). Oh well. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org