Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754529AbZGNOJT (ORCPT ); Tue, 14 Jul 2009 10:09:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754085AbZGNOJS (ORCPT ); Tue, 14 Jul 2009 10:09:18 -0400 Received: from cmpxchg.org ([85.214.51.133]:35212 "EHLO cmpxchg.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752466AbZGNOJS (ORCPT ); Tue, 14 Jul 2009 10:09:18 -0400 Date: Tue, 14 Jul 2009 16:08:39 +0200 From: Johannes Weiner To: Xiaotian Feng Cc: axboe@kernel.dk, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] block: slightly optimize blkdev_ioctl BLKRA{SET,GET} Message-ID: <20090714140839.GA18146@cmpxchg.org> References: <1247572794-24107-1-git-send-email-dfeng@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1247572794-24107-1-git-send-email-dfeng@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 536 Lines: 13 On Tue, Jul 14, 2009 at 07:59:54PM +0800, Xiaotian Feng wrote: > Slightly optimize blkdev_ioctl by using shift instead of multiply > and divide. Does it make an actual difference in the object code for you? I don't have a single multiplication in that function after compilation. Hannes -- 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/