From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail137.messagelabs.com (mail137.messagelabs.com [216.82.249.19]) by kanga.kvack.org (Postfix) with ESMTP id C6D115F0001 for ; Fri, 10 Apr 2009 01:28:36 -0400 (EDT) Date: Thu, 9 Apr 2009 22:25:12 -0700 From: Andrew Morton Subject: Re: [PATCH] memcg remove warning at DEBUG_VM=off Message-Id: <20090409222512.bd026a40.akpm@linux-foundation.org> In-Reply-To: <20090408052715.GX7082@balbir.in.ibm.com> References: <20090408142042.3fb62eea.kamezawa.hiroyu@jp.fujitsu.com> <20090408052715.GX7082@balbir.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: balbir@linux.vnet.ibm.com Cc: KAMEZAWA Hiroyuki , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "nishimura@mxp.nes.nec.co.jp" List-ID: On Wed, 8 Apr 2009 10:57:15 +0530 Balbir Singh wrote: > * KAMEZAWA Hiroyuki [2009-04-08 14:20:42]: > > > From: KAMEZAWA Hiroyuki > > This is against 2.6.30-rc1. (maybe no problem against mmotm.) > > > > == > > Fix warning as > > > > CC mm/memcontrol.o > > mm/memcontrol.c:318: warning: ?$B!Fmem_cgroup_is_obsolete?$B!G defined but not used > > > > This is called only from VM_BUG_ON(). > > > > Signed-off-by: KAMEZAWA Hiroyuki > > --- > > Index: linux-2.6.30-rc1/mm/memcontrol.c > > =================================================================== > > --- linux-2.6.30-rc1.orig/mm/memcontrol.c > > +++ linux-2.6.30-rc1/mm/memcontrol.c > > @@ -314,13 +314,14 @@ static struct mem_cgroup *try_get_mem_cg > > return mem; > > } > > > > +#ifdef CONFIG_DEBUG_VM > > static bool mem_cgroup_is_obsolete(struct mem_cgroup *mem) > > { > > if (!mem) > > return true; > > return css_is_removed(&mem->css); > > } > > - > > +#endif > > Can we change the code to use > > VM_BUG_ON(!mem || css_is_removed(&mem->css)); > yup. --- a/mm/memcontrol.c~memcg-remove-warning-when-config_debug_vm=n-fix +++ a/mm/memcontrol.c @@ -314,14 +314,13 @@ static struct mem_cgroup *try_get_mem_cg return mem; } -#ifdef CONFIG_DEBUG_VM static bool mem_cgroup_is_obsolete(struct mem_cgroup *mem) { if (!mem) return true; return css_is_removed(&mem->css); } -#endif + /* * Call callback function against all cgroup under hierarchy tree. @@ -933,7 +932,7 @@ static int __mem_cgroup_try_charge(struc if (unlikely(!mem)) return 0; - VM_BUG_ON(mem_cgroup_is_obsolete(mem)); + VM_BUG_ON(!mem || mem_cgroup_is_obsolete(mem)); while (1) { int ret; _ Although it really should be VM_BUG_ON(!mem); VM_BUG_ON(mem_cgroup_is_obsolete(mem)); because if that BUG triggers, you'll be wondering which case caused it. -- 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