From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755464Ab1HWQzI (ORCPT ); Tue, 23 Aug 2011 12:55:08 -0400 Received: from mx1.redhat.com ([209.132.183.28]:24593 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751259Ab1HWQzD (ORCPT ); Tue, 23 Aug 2011 12:55:03 -0400 Date: Tue, 23 Aug 2011 18:54:53 +0200 From: Andrea Arcangeli To: Minchan Kim Cc: Michel Lespinasse , Andrew Morton , linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hugh Dickins , Johannes Weiner , Rik van Riel , Mel Gorman , KOSAKI Motohiro , Shaohua Li Subject: Re: [PATCH] thp: tail page refcounting fix Message-ID: <20110823165453.GB23870@redhat.com> References: <1313740111-27446-1-git-send-email-walken@google.com> <20110822213347.GF2507@redhat.com> <20110823164515.GA2653@barrios-desktop> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20110823164515.GA2653@barrios-desktop> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Aug 24, 2011 at 01:45:15AM +0900, Minchan Kim wrote: > Nice idea! Thanks! It felt natural to account the tail refcounts in page_tail->_count, so they were already there and it was enough to add the page_mapcount(head_page) to the page_tail->_count. But there's no particular reason we had to do the tail_page refcounting in the ->_page field before the split... > Reviewed-by: Minchan Kim > > The code looks good to me. Thanks a lot for the quick review. > The nitpick is about naming 'foll'. > What does it mean? 'follow'? > If it is, I hope we use full name. > Regardless of renaming it, I am okay the patch. Ok the name comes from FOLL_GET. Only code paths marked by checking FOLL_GET are allowed to call get_page_foll(). Anything else can't. mm/*memory.c: if (flags & FOLL_GET) get_page_foll(page);