From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from psmtp.com (na3sys010amx176.postini.com [74.125.245.176]) by kanga.kvack.org (Postfix) with SMTP id AB9976B0033 for ; Sun, 16 Jun 2013 21:56:00 -0400 (EDT) Message-ID: <51BE6BFC.3030009@cn.fujitsu.com> Date: Mon, 17 Jun 2013 09:53:00 +0800 From: Zhang Yanfei MIME-Version: 1.0 Subject: Re: [PATCH] mm: Add unlikely for current_order test References: <51BC4A83.50302@gmail.com> In-Reply-To: Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=ISO-8859-1 Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Zhang Yanfei , Andrew Morton , Linux MM , "linux-kernel@vger.kernel.org" Hi David, On 06/17/2013 02:04 AM, David Rientjes wrote: > On Sat, 15 Jun 2013, Zhang Yanfei wrote: > >> From: Zhang Yanfei >> >> Since we have an unlikely for the "current_order >= pageblock_order / 2" >> test above, adding an unlikely for this "current_order >= pageblock_order" >> test seems more appropriate. >> > > I don't understand the justification at all, current_order being unlikely > greater than or equal to pageblock_order / 2 doesn't imply at all that > it's unlikely that current_order is greater than or equal to > pageblock_order. > hmmm... I am confused. Since current_order is >= pageblock_order / 2 is unlikely, why current_order is >= pageblock_order isn't unlikely. Or there are other tips? Actually, I am also a little confused about why current_order should be unlikely greater than or equal to pageblock_order / 2. When borrowing pages with other migrate_type, we always search from MAX_ORDER-1, which is greater or equal to pageblock_order. -- Thanks. Zhang Yanfei -- 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