From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx119.postini.com [74.125.245.119]) by kanga.kvack.org (Postfix) with SMTP id 461926B004D for ; Wed, 14 Nov 2012 13:01:30 -0500 (EST) Message-ID: <50A3DC54.8010206@redhat.com> Date: Wed, 14 Nov 2012 13:00:52 -0500 From: Rik van Riel MIME-Version: 1.0 Subject: Re: [PATCH 17/31] mm: numa: Avoid double faulting after migrating misplaced page References: <1352805180-1607-1-git-send-email-mgorman@suse.de> <1352805180-1607-18-git-send-email-mgorman@suse.de> In-Reply-To: <1352805180-1607-18-git-send-email-mgorman@suse.de> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org List-ID: To: Mel Gorman Cc: Peter Zijlstra , Andrea Arcangeli , Ingo Molnar , Johannes Weiner , Hugh Dickins , Thomas Gleixner , Linus Torvalds , Andrew Morton , Linux-MM , LKML On 11/13/2012 06:12 AM, Mel Gorman wrote: > The pte_same check after a misplaced page is successfully migrated will > never succeed and force a double fault to fix it up as pointed out by Rik > van Riel. This was the "safe" option but it's expensive. > > This patch uses the migration allocation callback to record the location > of the newly migrated page. If the page is the same when the PTE lock is > reacquired it is assumed that it is safe to complete the pte_numa fault > without incurring a double fault. > > Signed-off-by: Mel Gorman Reviewed-by: Rik van Riel -- All rights reversed -- 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