Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1423167AbXBUVXP (ORCPT ); Wed, 21 Feb 2007 16:23:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1423137AbXBUVVj (ORCPT ); Wed, 21 Feb 2007 16:21:39 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:40430 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1423149AbXBUVVP (ORCPT ); Wed, 21 Feb 2007 16:21:15 -0500 Date: Wed, 21 Feb 2007 22:16:02 +0100 From: Ingo Molnar To: linux-kernel@vger.kernel.org Cc: Linus Torvalds , Arjan van de Ven , Christoph Hellwig , Andrew Morton , Alan Cox , Ulrich Drepper , Zach Brown , Evgeniy Polyakov , "David S. Miller" , Suparna Bhattacharya , Davide Libenzi , Jens Axboe , Thomas Gleixner Subject: [patch 13/13] syslets: x86: optimized sys_umem_add() Message-ID: <20070221211602.GM7579@elte.hu> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070221211355.GA7302@elte.hu> User-Agent: Mutt/1.4.2.2i X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -5.3 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-5.3 required=5.9 tests=ALL_TRUSTED,BAYES_00 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1374 Lines: 54 From: Ingo Molnar provide an optimized assembly version of sys_umem_add(). It is about 2 times faster than the C version. Signed-off-by: Ingo Molnar Signed-off-by: Arjan van de Ven --- arch/i386/lib/getuser.S | 27 +++++++++++++++++++++++++++ 1 file changed, 27 insertions(+) Index: linux/arch/i386/lib/getuser.S =================================================================== --- linux.orig/arch/i386/lib/getuser.S +++ linux/arch/i386/lib/getuser.S @@ -11,6 +11,33 @@ #include /* + * Optimized user-memory arithmetics system-call: + */ + +.text +.align 4 +.globl sys_umem_add +sys_umem_add: + movl 0x4(%esp), %ecx # uptr + movl 0x8(%esp), %edx # inc + + cmpl $__PAGE_OFFSET, %ecx # access_ok(uptr) + jae bad_sys_umem_add + +1: addl %edx, (%ecx) # *uptr += inc +2: movl (%ecx), %eax # return *uptr + ret + +bad_sys_umem_add: + movl $-14, %eax + ret + +.section __ex_table,"a" + .long 1b, bad_sys_umem_add + .long 2b, bad_sys_umem_add +.previous + +/* * copy_uatom() - copy a syslet_atom from user-space into kernel-space: */ - 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/