From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f42.google.com (mail-pa0-f42.google.com [209.85.220.42]) by kanga.kvack.org (Postfix) with ESMTP id 3279C6B0035 for ; Wed, 13 Aug 2014 04:21:00 -0400 (EDT) Received: by mail-pa0-f42.google.com with SMTP id lf10so14592541pab.1 for ; Wed, 13 Aug 2014 01:20:59 -0700 (PDT) Received: from lgeamrelo02.lge.com (lgeamrelo02.lge.com. [156.147.1.126]) by mx.google.com with ESMTP id yp8si946752pac.193.2014.08.13.01.20.58 for ; Wed, 13 Aug 2014 01:20:59 -0700 (PDT) Date: Wed, 13 Aug 2014 17:20:57 +0900 From: Joonsoo Kim Subject: Re: [PATCH v2 2/8] mm/page_alloc: correct to clear guard attribute in DEBUG_PAGEALLOC Message-ID: <20140813082057.GD30451@js1304-P5Q-DELUXE> References: <1407309517-3270-1-git-send-email-iamjoonsoo.kim@lge.com> <1407309517-3270-5-git-send-email-iamjoonsoo.kim@lge.com> <20140812014523.GB23418@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140812014523.GB23418@gmail.com> Sender: owner-linux-mm@kvack.org List-ID: To: Minchan Kim Cc: Andrew Morton , "Kirill A. Shutemov" , Rik van Riel , Mel Gorman , Johannes Weiner , Yasuaki Ishimatsu , Zhang Yanfei , "Srivatsa S. Bhat" , Tang Chen , Naoya Horiguchi , Bartlomiej Zolnierkiewicz , Wen Congyang , Marek Szyprowski , Michal Nazarewicz , Laura Abbott , Heesub Shin , "Aneesh Kumar K.V" , Ritesh Harjani , t.stanislaws@samsung.com, Gioh Kim , linux-mm@kvack.org, linux-kernel@vger.kernel.org On Tue, Aug 12, 2014 at 01:45:23AM +0000, Minchan Kim wrote: > On Wed, Aug 06, 2014 at 04:18:30PM +0900, Joonsoo Kim wrote: > > In __free_one_page(), we check the buddy page if it is guard page. > > And, if so, we should clear guard attribute on the buddy page. But, > > currently, we clear original page's order rather than buddy one's. > > This doesn't have any problem, because resetting buddy's order > > is useless and the original page's order is re-assigned soon. > > But, it is better to correct code. > > > > Additionally, I change (set/clear)_page_guard_flag() to > > (set/clear)_page_guard() and makes these functions do all works > > needed for guard page. This may make code more understandable. > > > > One more thing, I did in this patch, is that fixing freepage accounting. > > If we clear guard page and link it onto isolate buddy list, we should > > not increase freepage count. > > You are saying just "shouldn't do that" but don't say "why" and "result" > I know the reason but as you know, I'm one of the person who is rather > familiar with this part but I guess others should spend some time to get. > Kind detail description is never to look down on person. :) Hmm. In fact, the reason is already mentioned in cover letter, but, it is better to write it here. Will do. > > > > Nice catch, Joonsoo! But what make me worry is is this patch makes 3 thing > all at once. > > 1. fix - no candidate for stable > 2. clean up > 3. fix - candidate for stable. > > Could you separate 3 and (1,2) in next spin? > Okay! Thanks. -- 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