From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id CB2E16B004A for ; Mon, 6 Jun 2011 06:39:29 -0400 (EDT) Date: Mon, 6 Jun 2011 11:39:24 +0100 From: Mel Gorman Subject: Re: [PATCH] mm: compaction: Abort compaction if too many pages are isolated and caller is asynchronous Message-ID: <20110606103924.GD5247@suse.de> References: <20110601191529.GY19505@random.random> <20110601214018.GC7306@suse.de> <20110601233036.GZ19505@random.random> <20110602010352.GD7306@suse.de> <20110602132954.GC19505@random.random> <20110602145019.GG7306@suse.de> <20110602153754.GF19505@random.random> <20110603020920.GA26753@suse.de> <20110603144941.GI7306@suse.de> <20110603154554.GK2802@random.random> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <20110603154554.GK2802@random.random> Sender: owner-linux-mm@kvack.org List-ID: To: Andrea Arcangeli Cc: Minchan Kim , akpm@linux-foundation.org, Ury Stankevich , KOSAKI Motohiro , linux-kernel@vger.kernel.org, linux-mm@kvack.org, stable@kernel.org On Fri, Jun 03, 2011 at 05:45:54PM +0200, Andrea Arcangeli wrote: > On Fri, Jun 03, 2011 at 03:49:41PM +0100, Mel Gorman wrote: > > Right idea of the wrong zone being accounted for but wrong place. I > > think the following patch should fix the problem; > > Looks good thanks. > > I also found this bug during my debugging that made NR_SHMEM underflow. > > === > Subject: migrate: don't account swapcache as shmem > > From: Andrea Arcangeli > > swapcache will reach the below code path in migrate_page_move_mapping, > and swapcache is accounted as NR_FILE_PAGES but it's not accounted as > NR_SHMEM. > > Signed-off-by: Andrea Arcangeli Well spotted. Acked-by: Mel Gorman Minor nit. swapper_space is rarely referred to outside of the swap code. Might it be more readable to use /* * swapcache is accounted as NR_FILE_PAGES but it is not * accounted as NR_SHMEM * if (PageSwapBacked(page) && !PageSwapCache(page)) ? > --- > > diff --git a/mm/migrate.c b/mm/migrate.c > index e4a5c91..2597a27 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -288,7 +288,7 @@ static int migrate_page_move_mapping(struct address_space *mapping, > */ > __dec_zone_page_state(page, NR_FILE_PAGES); > __inc_zone_page_state(newpage, NR_FILE_PAGES); > - if (PageSwapBacked(page)) { > + if (mapping != &swapper_space && PageSwapBacked(page)) { > __dec_zone_page_state(page, NR_SHMEM); > __inc_zone_page_state(newpage, NR_SHMEM); > } > > -- Mel Gorman SUSE Labs -- 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/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org