Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757768AbZGCMpY (ORCPT ); Fri, 3 Jul 2009 08:45:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1757596AbZGCMos (ORCPT ); Fri, 3 Jul 2009 08:44:48 -0400 Received: from hera.kernel.org ([140.211.167.34]:59875 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757564AbZGCMor (ORCPT ); Fri, 3 Jul 2009 08:44:47 -0400 Date: Fri, 3 Jul 2009 12:43:17 GMT From: tip-bot for Eric Dumazet To: linux-tip-commits@vger.kernel.org Cc: linux-kernel@vger.kernel.org, acme@redhat.com, paulus@samba.org, hpa@zytor.com, mingo@redhat.com, eric.dumazet@gmail.com, a.p.zijlstra@chello.nl, torvalds@linux-foundation.org, efault@gmx.de, arnd@arndb.de, dhowells@redhat.com, fweisbec@gmail.com, akpm@linux-foundation.org, tglx@linutronix.de, mingo@elte.hu Reply-To: mingo@redhat.com, hpa@zytor.com, paulus@samba.org, acme@redhat.com, linux-kernel@vger.kernel.org, eric.dumazet@gmail.com, torvalds@linux-foundation.org, a.p.zijlstra@chello.nl, efault@gmx.de, arnd@arndb.de, fweisbec@gmail.com, dhowells@redhat.com, akpm@linux-foundation.org, tglx@linutronix.de, mingo@elte.hu In-Reply-To: References: Subject: [tip:perfcounters/urgent] x86: atomic64: Improve cmpxchg8b() Message-ID: Git-Commit-ID: 69237f94e65d3d7f539f1adb98ef68685c595004 X-Mailer: tip-git-log-daemon MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.0 (hera.kernel.org [127.0.0.1]); Fri, 03 Jul 2009 12:43:18 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1982 Lines: 66 Commit-ID: 69237f94e65d3d7f539f1adb98ef68685c595004 Gitweb: http://git.kernel.org/tip/69237f94e65d3d7f539f1adb98ef68685c595004 Author: Eric Dumazet AuthorDate: Fri, 3 Jul 2009 13:26:41 +0200 Committer: Ingo Molnar CommitDate: Fri, 3 Jul 2009 13:26:41 +0200 x86: atomic64: Improve cmpxchg8b() Rewrite cmpxchg8b() to not use %edi register but a generic "+m" constraint, to increase compiler freedom in code generation and possibly better code. Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Mike Galbraith Cc: Paul Mackerras Cc: Arnaldo Carvalho de Melo Cc: Frederic Weisbecker Cc: David Howells Cc: Andrew Morton Cc: Arnd Bergmann LKML-Reference: Signed-off-by: Ingo Molnar --- arch/x86/lib/atomic64_32.c | 19 +++++++------------ 1 files changed, 7 insertions(+), 12 deletions(-) diff --git a/arch/x86/lib/atomic64_32.c b/arch/x86/lib/atomic64_32.c index afa5d44..5fc1e2c 100644 --- a/arch/x86/lib/atomic64_32.c +++ b/arch/x86/lib/atomic64_32.c @@ -6,19 +6,14 @@ static inline u64 cmpxchg8b(u64 *ptr, u64 old, u64 new) { - asm volatile( - - LOCK_PREFIX "cmpxchg8b (%[ptr])\n" - - : "=A" (old) - - : [ptr] "D" (ptr), - "A" (old), - "b" (ll_low(new)), - "c" (ll_high(new)) - - : "memory"); + u32 low = new; + u32 high = new >> 32; + asm volatile( + LOCK_PREFIX "cmpxchg8b %1\n" + : "+A" (old), "+m" (*ptr) + : "b" (low), "c" (high) + ); return old; } -- 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/