Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755882Ab2ENKIe (ORCPT ); Mon, 14 May 2012 06:08:34 -0400 Received: from mail-lb0-f174.google.com ([209.85.217.174]:57182 "EHLO mail-lb0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755709Ab2ENKId convert rfc822-to-8bit (ORCPT ); Mon, 14 May 2012 06:08:33 -0400 MIME-Version: 1.0 In-Reply-To: <4FB05B8F.8020408@jp.fujitsu.com> References: <4FACDED0.3020400@jp.fujitsu.com> <4FACE01A.4040405@jp.fujitsu.com> <20120511141945.c487e94c.akpm@linux-foundation.org> <4FB05B8F.8020408@jp.fujitsu.com> Date: Mon, 14 May 2012 12:08:31 +0200 Message-ID: Subject: Re: [PATCH 2/6] add res_counter_uncharge_until() From: Frederic Weisbecker To: KAMEZAWA Hiroyuki Cc: Andrew Morton , "linux-mm@kvack.org" , "cgroups@vger.kernel.org" , Michal Hocko , Johannes Weiner , Han Ying , Glauber Costa , Tejun Heo , "Aneesh Kumar K.V" , Hiroyuki Kamezawa , Linux Kernel Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1884 Lines: 49 2012/5/14 KAMEZAWA Hiroyuki : > (2012/05/12 6:19), Andrew Morton wrote: > >> On Fri, 11 May 2012 18:47:06 +0900 >> KAMEZAWA Hiroyuki wrote: >> >>> From: Frederic Weisbecker >>> >>> At killing res_counter which is a child of other counter, >>> we need to do >>> ? ? ?res_counter_uncharge(child, xxx) >>> ? ? ?res_counter_charge(parent, xxx) >>> >>> This is not atomic and wasting cpu. This patch adds >>> res_counter_uncharge_until(). This function's uncharge propagates >>> to ancestors until specified res_counter. >>> >>> ? ? ?res_counter_uncharge_until(child, parent, xxx) >>> >>> Now, ops is atomic and efficient. >>> >>> Changelog since v2 >>> ?- removed unnecessary lines. >>> ?- Fixed 'From' , this patch comes from his series. Please signed-off-by if good. >>> >>> Signed-off-by: KAMEZAWA Hiroyuki >> >> Frederic's Signed-off-by: is unavaliable? >> > > I didn't add his Signed-off because I modified his orignal patch a little... > I dropped res_counter_charge_until() because it's not used in this series, > I have no justification for adding it. > The idea of res_counter_uncharge_until() is from his patch. The property of Signed-off-by is that as long as you carry/relay/modify a patch, you add your own signed-off-by. But you can't remove the signed off by of somebody in the chain. Even if you did a change in the patch, you need to preserve the chain. There may be some special cases with "Original-patch-from:" tags used when one heavily inspire from a patch without taking much of its original code. -- 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/