From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with SMTP id 050866B0088 for ; Tue, 23 Nov 2010 19:29:15 -0500 (EST) Received: from m2.gw.fujitsu.co.jp ([10.0.50.72]) by fgwmail7.fujitsu.co.jp (Fujitsu Gateway) with ESMTP id oAO0TD5r015345 for (envelope-from kamezawa.hiroyu@jp.fujitsu.com); Wed, 24 Nov 2010 09:29:14 +0900 Received: from smail (m2 [127.0.0.1]) by outgoing.m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 682BD45DD77 for ; Wed, 24 Nov 2010 09:29:13 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (s2.gw.fujitsu.co.jp [10.0.50.92]) by m2.gw.fujitsu.co.jp (Postfix) with ESMTP id 3670B45DD75 for ; Wed, 24 Nov 2010 09:29:13 +0900 (JST) Received: from s2.gw.fujitsu.co.jp (localhost.localdomain [127.0.0.1]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id 1DAECE08002 for ; Wed, 24 Nov 2010 09:29:13 +0900 (JST) Received: from ml13.s.css.fujitsu.com (ml13.s.css.fujitsu.com [10.249.87.103]) by s2.gw.fujitsu.co.jp (Postfix) with ESMTP id CB5001DB8038 for ; Wed, 24 Nov 2010 09:29:12 +0900 (JST) Date: Wed, 24 Nov 2010 09:23:37 +0900 From: KAMEZAWA Hiroyuki Subject: Re: [PATCH] [BUG] memcg: fix false positive VM_BUG on non-SMP Message-Id: <20101124092337.b9fe888f.kamezawa.hiroyu@jp.fujitsu.com> In-Reply-To: <20101123225244.GB22484@cmpxchg.org> 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> Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Johannes Weiner Cc: Andrew Morton , "Kirill A. Shutsemov" , Balbir Singh , Daisuke Nishimura , KOSAKI Motohiro , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: 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 Thank you. -- 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