Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936892AbXHNW5j (ORCPT ); Tue, 14 Aug 2007 18:57:39 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S935950AbXHNWy1 (ORCPT ); Tue, 14 Aug 2007 18:54:27 -0400 Received: from Chamillionaire.breakpoint.cc ([85.10.199.196]:43204 "EHLO Chamillionaire.breakpoint.cc" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935928AbXHNWyV (ORCPT ); Tue, 14 Aug 2007 18:54:21 -0400 Message-Id: <20070814224337.547449183@breakpoint.cc> References: <20070814223845.518697567@breakpoint.cc> User-Agent: quilt/0.46-1 Date: Wed, 15 Aug 2007 00:38:46 +0200 From: Sebastian Siewior To: linux-kernel@vger.kernel.org Cc: Andi Kleen Subject: [patch 1/2] i386: use asm() like the other atomic operations already do. Content-Disposition: inline; filename=atomic_i386.diff Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1936 Lines: 66 As Segher pointed out, inline asm is better than the volatile casting all over the place. From the PowerPC patch description: Also use inline functions instead of macros; this actually improves code generation (some code becomes a little smaller, probably because of improved alias information -- just a few hundred bytes total on a default kernel build, nothing shocking). My config with march=pentium-m and gcc (GCC) 4.1.2 (Gentoo 4.1.2): text data bss dec hex filename 3434150 249176 176128 3859454 3ae3fe atomic_normal/vmlinux 3435308 249176 176128 3860612 3ae884 atomic_inlineasm/vmlinux 3436201 249176 176128 3861505 3aec01 atomic_inline_volatile/vmlinux 3436203 249176 176128 3861507 3aec03 atomic_volatile/vmlinux Signed-off-by: Sebastian Siewior --- a/include/asm-i386/atomic.h +++ b/include/asm-i386/atomic.h @@ -22,19 +22,34 @@ typedef struct { int counter; } atomic_t /** * atomic_read - read atomic variable * @v: pointer of type atomic_t - * + * * Atomically reads the value of @v. - */ -#define atomic_read(v) ((v)->counter) + */ +static __inline__ int atomic_read(const atomic_t *v) +{ + int t; + + __asm__ __volatile__( + "movl %1,%0" + : "=r"(t) + : "m"(v->counter)); + return t; +} /** * atomic_set - set atomic variable * @v: pointer of type atomic_t * @i: required value - * + * * Atomically sets the value of @v to @i. - */ -#define atomic_set(v,i) (((v)->counter) = (i)) + */ +static __inline__ void atomic_set(atomic_t *v, int i) +{ + __asm__ __volatile__( + "movl %1,%0" + : "=m"(v->counter) + : "ir"(i)); +} /** * atomic_add - add integer to atomic variable -- - 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/