Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752110Ab2FRNVt (ORCPT ); Mon, 18 Jun 2012 09:21:49 -0400 Received: from mx2.parallels.com ([64.131.90.16]:53717 "EHLO mx2.parallels.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751042Ab2FRNVr (ORCPT ); Mon, 18 Jun 2012 09:21:47 -0400 Message-ID: <4FDF2AD6.7060606@parallels.com> Date: Mon, 18 Jun 2012 17:19:18 +0400 From: Glauber Costa User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:13.0) Gecko/20120605 Thunderbird/13.0 MIME-Version: 1.0 To: Wanpeng Li CC: Johannes Weiner , Michal Hocko , Balbir Singh , KAMEZAWA Hiroyuki , , , , Gavin Shan Subject: Re: [PATCH] mm/memcg: add unlikely to mercg->move_charge_at_immigrate References: <1340025022-7272-1-git-send-email-liwp.linux@gmail.com> <4FDF2890.3020004@parallels.com> <20120618131918.GA2600@kernel> In-Reply-To: <20120618131918.GA2600@kernel> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1054 Lines: 29 On 06/18/2012 05:19 PM, Wanpeng Li wrote: > On Mon, Jun 18, 2012 at 05:09:36PM +0400, Glauber Costa wrote: >> On 06/18/2012 05:10 PM, Wanpeng Li wrote: >>> From: Wanpeng Li >>> >>> move_charge_at_immigrate feature is disabled by default. Charges >>> are moved only when you move mm->owner and it also add additional >>> overhead. >> >> How big is this overhead? >> >> That's hardly a fast path. And if it happens to matter, it will be >> just bigger when you enable it, and the compiler start giving the >> wrong hints to the code. > > Thank you for your quick response. > > Oh, Maybe I should just write comments "move_charge_at_immigrate feature > is disabled by default. So add "unlikely", in order to compiler can optimize." > Again, do you have any reason to optimize that ? -- 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/