Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760244Ab1FXBT3 (ORCPT ); Thu, 23 Jun 2011 21:19:29 -0400 Received: from claw.goop.org ([74.207.240.146]:41596 "EHLO claw.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753097Ab1FXBT0 (ORCPT ); Thu, 23 Jun 2011 21:19:26 -0400 From: Jeremy Fitzhardinge To: Peter Zijlstra Cc: Linus Torvalds , "H. Peter Anvin" , Ingo Molnar , the arch/x86 maintainers , Linux Kernel Mailing List , Nick Piggin , Jeremy Fitzhardinge Subject: [PATCH 3/8] x86/ticketlock: Use C for __ticket_spin_unlock Date: Thu, 23 Jun 2011 18:19:15 -0700 Message-Id: X-Mailer: git-send-email 1.7.5.4 In-Reply-To: References: In-Reply-To: <05552e1c97739f589cb76c20b5a6565ccd506636.1308878118.git.jeremy.fitzhardinge@citrix.com> References: <05552e1c97739f589cb76c20b5a6565ccd506636.1308878118.git.jeremy.fitzhardinge@citrix.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2338 Lines: 80 From: Jeremy Fitzhardinge If we don't need to use a locked inc for unlock, then implement it in C. Signed-off-by: Jeremy Fitzhardinge --- arch/x86/include/asm/spinlock.h | 33 ++++++++++++++++++--------------- 1 files changed, 18 insertions(+), 15 deletions(-) diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h index f48a6e3..704b0c3 100644 --- a/arch/x86/include/asm/spinlock.h +++ b/arch/x86/include/asm/spinlock.h @@ -33,9 +33,21 @@ * On PPro SMP or if we are using OOSTORE, we use a locked operation to unlock * (PPro errata 66, 92) */ -# define UNLOCK_LOCK_PREFIX LOCK_PREFIX +static __always_inline void __ticket_unlock_release(struct arch_spinlock *lock) +{ + if (sizeof(lock->tickets.head) == sizeof(u8)) + asm (LOCK_PREFIX "incb %0" + : "+m" (lock->tickets.head) : : "memory"); + else + asm (LOCK_PREFIX "incw %0" + : "+m" (lock->tickets.head) : : "memory"); + +} #else -# define UNLOCK_LOCK_PREFIX +static __always_inline void __ticket_unlock_release(struct arch_spinlock *lock) +{ + lock->tickets.head++; +} #endif /* @@ -93,14 +105,6 @@ static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) return tmp; } - -static __always_inline void __ticket_spin_unlock(arch_spinlock_t *lock) -{ - asm volatile(UNLOCK_LOCK_PREFIX "incb %0" - : "+m" (lock->slock) - : - : "memory", "cc"); -} #else static __always_inline void __ticket_spin_lock(arch_spinlock_t *lock) { @@ -144,15 +148,14 @@ static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) return tmp; } +#endif static __always_inline void __ticket_spin_unlock(arch_spinlock_t *lock) { - asm volatile(UNLOCK_LOCK_PREFIX "incw %0" - : "+m" (lock->slock) - : - : "memory", "cc"); + barrier(); /* prevent reordering out of locked region */ + __ticket_unlock_release(lock); + barrier(); /* prevent reordering into locked region */ } -#endif static inline int __ticket_spin_is_locked(arch_spinlock_t *lock) { -- 1.7.5.4 -- 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/