From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with SMTP id A746C60044A for ; Mon, 21 Dec 2009 22:12:04 -0500 (EST) Received: by pzk27 with SMTP id 27so1684341pzk.12 for ; Mon, 21 Dec 2009 19:12:03 -0800 (PST) Message-ID: <4B3038F9.9040701@gmail.com> Date: Tue, 22 Dec 2009 11:11:53 +0800 From: Huang Shijie MIME-Version: 1.0 Subject: Re: [PATCH] mm : kill combined_idx References: <1261366347-19232-1-git-send-email-shijie8@gmail.com> <20091221143139.7088a8d3.kamezawa.hiroyu@jp.fujitsu.com> <20091221194337.GA23345@csn.ul.ie> In-Reply-To: <20091221194337.GA23345@csn.ul.ie> Content-Type: text/plain; charset=ISO-8859-15; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org To: Mel Gorman Cc: KAMEZAWA Hiroyuki , akpm@linux-foundation.org, linux-mm@kvack.org List-ID: >> Hmm...As far as I remember, this code design was for avoiding "if". >> Is this compare+jump is better than add+xor ? >> >> > > Agreed. It's not clear that a compare+jump is cheaper than the add+xor. > How often it's the case that the page is the higher or lower half of the > buddy would depend heavily on the allocation/free pattern making it > hard, if not possible, to predict which is the more common case. > > ok. thanks a lot. -- 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/ . Don't email: email@kvack.org