Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753192Ab3FQX4V (ORCPT ); Mon, 17 Jun 2013 19:56:21 -0400 Received: from mail-pb0-f44.google.com ([209.85.160.44]:51839 "EHLO mail-pb0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751361Ab3FQX4T (ORCPT ); Mon, 17 Jun 2013 19:56:19 -0400 Date: Mon, 17 Jun 2013 16:56:17 -0700 (PDT) From: David Rientjes X-X-Sender: rientjes@chino.kir.corp.google.com To: Zhang Yanfei cc: Andrew Morton , Linux MM , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH] mm: Remove unlikely from the current_order test In-Reply-To: <51BF8860.7010909@gmail.com> Message-ID: References: <51BF8860.7010909@gmail.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 905 Lines: 21 On Tue, 18 Jun 2013, Zhang Yanfei wrote: > From: Zhang Yanfei > > In __rmqueue_fallback(), current_order loops down from MAX_ORDER - 1 > to the order passed. MAX_ORDER is typically 11 and pageblock_order > is typically 9 on x86. Integer division truncates, so pageblock_order / 2 > is 4. For the first eight iterations, it's guaranteed that > current_order >= pageblock_order / 2 if it even gets that far! > > So just remove the unlikely(), it's completely bogus. > > Suggested-by: David Rientjes > Signed-off-by: Zhang Yanfei Acked-by: David Rientjes -- 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/