From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754884AbZLRQBS (ORCPT ); Fri, 18 Dec 2009 11:01:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754702AbZLRQBO (ORCPT ); Fri, 18 Dec 2009 11:01:14 -0500 Received: from vpn.id2.novell.com ([195.33.99.129]:39923 "EHLO vpn.id2.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754650AbZLRQBH convert rfc822-to-8bit (ORCPT ); Fri, 18 Dec 2009 11:01:07 -0500 Message-Id: <4B2BB5830200007800026AC7@vpn.id2.novell.com> X-Mailer: Novell GroupWise Internet Agent 8.0.1 Date: Fri, 18 Dec 2009 16:01:55 +0000 From: "Jan Beulich" To: , , Cc: "Peter Zijlstra" , "Linus Torvalds" , "Nick Piggin" , Subject: [PATCH] x86: slightly shorten __ticket_spin_trylock() (v3) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Since the callers generally expect a boolean value, there's no need to zero-extend the outcome of the comparison. It just requires that all of x86' trylock implementations have their return type changed accordingly. v2: Don't use bool for the return type though - this is being frowned on and presently doesn't work with the pv-ops patching macros. v3: Keep the return value in %eax (or really, %al). Signed-off-by: Jan Beulich Cc: Nick Piggin Cc: Linus Torvalds Cc: Peter Zijlstra --- arch/x86/include/asm/paravirt.h | 4 ++-- arch/x86/include/asm/paravirt_types.h | 2 +- arch/x86/include/asm/spinlock.h | 14 ++++++-------- arch/x86/xen/spinlock.c | 2 +- 4 files changed, 10 insertions(+), 12 deletions(-) --- linux-2.6.33-rc1/arch/x86/include/asm/paravirt.h 2009-12-18 16:05:40.000000000 +0100 +++ 2.6.33-rc1-x86-spin-trylock-simplify/arch/x86/include/asm/paravirt.h 2009-12-03 09:43:42.000000000 +0100 @@ -753,9 +753,9 @@ static __always_inline void arch_spin_lo PVOP_VCALL2(pv_lock_ops.spin_lock_flags, lock, flags); } -static __always_inline int arch_spin_trylock(struct arch_spinlock *lock) +static __always_inline u8 arch_spin_trylock(struct arch_spinlock *lock) { - return PVOP_CALL1(int, pv_lock_ops.spin_trylock, lock); + return PVOP_CALL1(u8, pv_lock_ops.spin_trylock, lock); } static __always_inline void arch_spin_unlock(struct arch_spinlock *lock) --- linux-2.6.33-rc1/arch/x86/include/asm/paravirt_types.h 2009-12-18 16:05:40.000000000 +0100 +++ 2.6.33-rc1-x86-spin-trylock-simplify/arch/x86/include/asm/paravirt_types.h 2009-12-03 09:43:50.000000000 +0100 @@ -324,7 +324,7 @@ struct pv_lock_ops { int (*spin_is_contended)(struct arch_spinlock *lock); void (*spin_lock)(struct arch_spinlock *lock); void (*spin_lock_flags)(struct arch_spinlock *lock, unsigned long flags); - int (*spin_trylock)(struct arch_spinlock *lock); + u8 (*spin_trylock)(struct arch_spinlock *lock); void (*spin_unlock)(struct arch_spinlock *lock); }; --- linux-2.6.33-rc1/arch/x86/include/asm/spinlock.h 2009-12-18 16:05:40.000000000 +0100 +++ 2.6.33-rc1-x86-spin-trylock-simplify/arch/x86/include/asm/spinlock.h 2009-12-10 15:30:52.000000000 +0100 @@ -77,7 +77,7 @@ static __always_inline void __ticket_spi : "memory", "cc"); } -static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) +static __always_inline u8 __ticket_spin_trylock(arch_spinlock_t *lock) { int tmp, new; @@ -87,8 +87,7 @@ static __always_inline int __ticket_spin "jne 1f\n\t" LOCK_PREFIX "cmpxchgw %w1,%2\n\t" "1:" - "sete %b1\n\t" - "movzbl %b1,%0\n\t" + "sete %b0\n\t" : "=&a" (tmp), "=&q" (new), "+m" (lock->slock) : : "memory", "cc"); @@ -127,7 +126,7 @@ static __always_inline void __ticket_spi : "memory", "cc"); } -static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) +static __always_inline u8 __ticket_spin_trylock(arch_spinlock_t *lock) { int tmp; int new; @@ -140,9 +139,8 @@ static __always_inline int __ticket_spin "jne 1f\n\t" LOCK_PREFIX "cmpxchgl %1,%2\n\t" "1:" - "sete %b1\n\t" - "movzbl %b1,%0\n\t" - : "=&a" (tmp), "=&q" (new), "+m" (lock->slock) + "sete %b0\n\t" + : "=&a" (tmp), "=&r" (new), "+m" (lock->slock) : : "memory", "cc"); @@ -190,7 +188,7 @@ static __always_inline void arch_spin_lo __ticket_spin_lock(lock); } -static __always_inline int arch_spin_trylock(arch_spinlock_t *lock) +static __always_inline u8 arch_spin_trylock(arch_spinlock_t *lock) { return __ticket_spin_trylock(lock); } --- linux-2.6.33-rc1/arch/x86/xen/spinlock.c 2009-12-18 16:05:40.000000000 +0100 +++ 2.6.33-rc1-x86-spin-trylock-simplify/arch/x86/xen/spinlock.c 2009-12-03 09:44:33.000000000 +0100 @@ -136,7 +136,7 @@ static int xen_spin_is_contended(struct return xl->spinners != 0; } -static int xen_spin_trylock(struct arch_spinlock *lock) +static u8 xen_spin_trylock(struct arch_spinlock *lock) { struct xen_spinlock *xl = (struct xen_spinlock *)lock; u8 old = 1;