From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757316AbaIIOwd (ORCPT ); Tue, 9 Sep 2014 10:52:33 -0400 Received: from cantor2.suse.de ([195.135.220.15]:48215 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753668AbaIIOwb (ORCPT ); Tue, 9 Sep 2014 10:52:31 -0400 Date: Tue, 9 Sep 2014 15:52:28 +0100 From: Mel Gorman To: Andrew Morton Cc: Johannes Weiner , Rik van Riel , David Rientjes , linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: [PATCH] mm: page_alloc: Make paranoid check in move_freepages a VM_BUG_ON Message-ID: <20140909145228.GB12309@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since 2.6.24 there has been a paranoid check in move_freepages that looks up the zone of two pages. This is a very slow path and the only time I've seen this bug trigger recently is when memory initialisation was broken during patch development. Despite the fact it's a slow path, this patch converts the check to a VM_BUG_ON anyway as it is served its purpose by now. Signed-off-by: Mel Gorman --- mm/page_alloc.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 0a7ed33..6fbd814 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -1014,7 +1014,7 @@ int move_freepages(struct zone *zone, * Remove at a later date when no bug reports exist related to * grouping pages by mobility */ - BUG_ON(page_zone(start_page) != page_zone(end_page)); + VM_BUG_ON(page_zone(start_page) != page_zone(end_page)); #endif for (page = start_page; page <= end_page;) {