From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754902AbXLSRPH (ORCPT ); Wed, 19 Dec 2007 12:15:07 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752078AbXLSRO5 (ORCPT ); Wed, 19 Dec 2007 12:14:57 -0500 Received: from e3.ny.us.ibm.com ([32.97.182.143]:45132 "EHLO e3.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751830AbXLSRO4 (ORCPT ); Wed, 19 Dec 2007 12:14:56 -0500 Subject: Re: [PATCH] Move page_assign_page_cgroup to VM_BUG_ON in free_hot_cold_page From: Dave Hansen To: Balbir Singh Cc: Hugh Dickins , LKML , Andrew Morton In-Reply-To: <20071219061834.8461.3974.sendpatchset@balbir-laptop> References: <20071219061834.8461.3974.sendpatchset@balbir-laptop> Content-Type: text/plain Date: Wed, 19 Dec 2007 09:14:33 -0800 Message-Id: <1198084473.15321.48.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.10.1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2007-12-19 at 11:48 +0530, Balbir Singh wrote: > diff -puN mm/page_alloc.c~memory-controller-move-to-bug-on-in-free_hot_cold_page mm/page_alloc.c > --- linux-2.6.24-rc5/mm/page_alloc.c~memory-controller-move-to-bug-on-in-free_hot_cold_page 2007-12-19 11:31:46.000000000 +0530 > +++ linux-2.6.24-rc5-balbir/mm/page_alloc.c 2007-12-19 11:33:45.000000000 +0530 > @@ -995,7 +995,7 @@ static void fastcall free_hot_cold_page( > > if (!PageHighMem(page)) > debug_check_no_locks_freed(page_address(page), PAGE_SIZE); > - page_assign_page_cgroup(page, NULL); > + VM_BUG_ON(page_get_page_cgroup(page)); > arch_free_page(page, 0); > kernel_map_pages(page, 1, 0); Hi Balbir, You generally want to do these like: foo = page_assign_page_cgroup(page, NULL); VM_BUG_ON(foo); Some embedded people have been known to optimize kernel size like this: #define VM_BUG_ON(x) do{}while(0) -- Dave