From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx120.postini.com [74.125.245.120]) by kanga.kvack.org (Postfix) with SMTP id A28876B005C for ; Wed, 13 Jun 2012 21:49:51 -0400 (EDT) Message-ID: <4FD9433C.4060503@kernel.org> Date: Thu, 14 Jun 2012 10:49:48 +0900 From: Minchan Kim MIME-Version: 1.0 Subject: Re: [PATCH] mm: do not use page_count without a page pin References: <1339373872-31969-1-git-send-email-minchan@kernel.org> <4FD59C31.6000606@jp.fujitsu.com> <20120611074440.GI3094@redhat.com> <20120611133043.GA2340@barrios> <20120611144132.GT3094@redhat.com> <4FD675FE.1060202@kernel.org> <20120614012103.GY3094@redhat.com> In-Reply-To: <20120614012103.GY3094@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Andrea Arcangeli Cc: Kamezawa Hiroyuki , Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org, Mel Gorman , Michal Hocko On 06/14/2012 10:21 AM, Andrea Arcangeli wrote: > On Tue, Jun 12, 2012 at 07:49:34AM +0900, Minchan Kim wrote: >> If THP page isn't LRU and it's still PageTransHuge, I think it's rather rare and >> although it happens, it means migration/reclaimer is about to split or isolate/putback >> so it ends up making THP page movable pages. >> >> IMHO, it would be better to account it by movable pages. >> What do you think about it? > > Agreed. Besides THP don't fragment pageblocks. It was just about > speeding up the scanning the same way it happens with the pagebuddy > check, but probably not worth it because we're in a racy area here not > holding locks. pagebuddy is safe because the zone lock is hold, or > it'd run in the same problem. Yeb. zone lock is already hold so pagebuddy check is safe but THP still in a racy so let's leave it as it is. If you don't have concern about this patch any more, could you add Acked-by in my latest patch for Andrew to pick up? Although you have a concern, let's make it as separate patch because it's optimization patch and other patch is pending by this. Thanks, Andrea. -- Kind regards, Minchan Kim -- 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