From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx123.postini.com [74.125.245.123]) by kanga.kvack.org (Postfix) with SMTP id 909386B004D for ; Mon, 14 May 2012 06:08:33 -0400 (EDT) Received: by lahi5 with SMTP id i5so4998670lah.14 for ; Mon, 14 May 2012 03:08:31 -0700 (PDT) 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 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Sender: owner-linux-mm@kvack.org List-ID: 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 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 >>> =A0 =A0 =A0res_counter_uncharge(child, xxx) >>> =A0 =A0 =A0res_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. >>> >>> =A0 =A0 =A0res_counter_uncharge_until(child, parent, xxx) >>> >>> Now, ops is atomic and efficient. >>> >>> Changelog since v2 >>> =A0- removed unnecessary lines. >>> =A0- 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, 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 internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org