From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with ESMTP id 142FF8D0001 for ; Thu, 25 Nov 2010 22:24:00 -0500 (EST) Received: from d01dlp02.pok.ibm.com (d01dlp02.pok.ibm.com [9.56.224.85]) by e4.ny.us.ibm.com (8.14.4/8.13.1) with ESMTP id oAQ3753V001255 for ; Thu, 25 Nov 2010 22:07:05 -0500 Received: from d01relay03.pok.ibm.com (d01relay03.pok.ibm.com [9.56.227.235]) by d01dlp02.pok.ibm.com (Postfix) with ESMTP id EDED14DE803D for ; Thu, 25 Nov 2010 22:22:30 -0500 (EST) Received: from d01av02.pok.ibm.com (d01av02.pok.ibm.com [9.56.224.216]) by d01relay03.pok.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id oAQ3NvIC348662 for ; Thu, 25 Nov 2010 22:23:57 -0500 Received: from d01av02.pok.ibm.com (loopback [127.0.0.1]) by d01av02.pok.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id oAQ3NvdM013263 for ; Fri, 26 Nov 2010 01:23:57 -0200 Date: Fri, 26 Nov 2010 08:53:55 +0530 From: Balbir Singh Subject: Re: [PATCH] [BUG] memcg: fix false positive VM_BUG on non-SMP Message-ID: <20101126032355.GG3298@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: <1290520130-9990-1-git-send-email-kirill@shutemov.name> <20101123121606.c07197e5.akpm@linux-foundation.org> <20101123210255.GA22484@cmpxchg.org> <20101123142247.e8566e3e.akpm@linux-foundation.org> <20101123225244.GB22484@cmpxchg.org> <20101124092337.b9fe888f.kamezawa.hiroyu@jp.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: <20101124092337.b9fe888f.kamezawa.hiroyu@jp.fujitsu.com> Sender: owner-linux-mm@kvack.org To: KAMEZAWA Hiroyuki Cc: Johannes Weiner , Andrew Morton , "Kirill A. Shutsemov" , Daisuke Nishimura , KOSAKI Motohiro , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: * KAMEZAWA Hiroyuki [2010-11-24 09:23:37]: > On Tue, 23 Nov 2010 23:52:44 +0100 > Johannes Weiner wrote: > > > On Tue, Nov 23, 2010 at 02:22:47PM -0800, Andrew Morton wrote: > > > On Tue, 23 Nov 2010 22:02:55 +0100 > > > Johannes Weiner wrote: > > > > > > > On Tue, Nov 23, 2010 at 12:16:06PM -0800, Andrew Morton wrote: > > > > > On Tue, 23 Nov 2010 15:48:50 +0200 > > > > > "Kirill A. Shutsemov" wrote: > > > > > > > > > > > ------------[ cut here ]------------ > > > > > > kernel BUG at mm/memcontrol.c:2155! > > > > > > > > > > This bug has been there for a year, from which I conclude people don't > > > > > run memcg on uniprocessor machines a lot. > > > > > > > > > > Which is a bit sad, really. Small machines need resource control too, > > > > > perhaps more than large ones.. > > > > > > > > Admittedly, this patch is compile-tested on UP only, but it should be > > > > obvious enough. > > > > > > > > --- > > > > From: Johannes Weiner > > > > Subject: [patch] memcg: fix page cgroup lock assert on UP > > > > > > > > Page cgroup locking primitives use the bit spinlock API functions, > > > > which do nothing on UP. > > > > > > > > Thus, checking the lock state can not be done by looking at the bit > > > > directly, but one has to go through the bit spinlock API as well. > > > > > > > > This fixes a guaranteed UP bug, where asserting the page cgroup lock > > > > bit as a sanity check crashes the kernel. > > > > > > > > > > hm, your patch is the same as Kirill's, except you named it > > > page_is_cgroup_locked() rather than is_page_cgroup_locked(). I guess > > > page_is_cgroup_locked() is a bit better. > > > > I had not sorted by threads and somehow assumed this was another > > forward from you of a bugzilla report or something. I didn't see > > Kirill's patch until now. Sorry! > > > > Reviewed-by: Johannes Weiner > > Acked-by: KAMEZAWA Hiroyuki > Great catch! Thanks Acked-by: Balbir Singh -- Three Cheers, Balbir -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org