Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752948Ab0KZDYA (ORCPT ); Thu, 25 Nov 2010 22:24:00 -0500 Received: from e5.ny.us.ibm.com ([32.97.182.145]:44078 "EHLO e5.ny.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752349Ab0KZDX7 (ORCPT ); Thu, 25 Nov 2010 22:23:59 -0500 Date: Fri, 26 Nov 2010 08:53:55 +0530 From: Balbir Singh To: KAMEZAWA Hiroyuki Cc: Johannes Weiner , Andrew Morton , "Kirill A. Shutsemov" , Daisuke Nishimura , KOSAKI Motohiro , linux-kernel@vger.kernel.org, linux-mm@kvack.org 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> User-Agent: Mutt/1.5.21 (2010-09-15) X-Content-Scanned: Fidelis XPS MAILER Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2415 Lines: 66 * 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 from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/