From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755340Ab1GVT5e (ORCPT ); Fri, 22 Jul 2011 15:57:34 -0400 Received: from hera.kernel.org ([140.211.167.34]:38179 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751481Ab1GVT5c (ORCPT ); Fri, 22 Jul 2011 15:57:32 -0400 Date: Fri, 22 Jul 2011 19:57:25 GMT From: tip-bot for Jeremy Fitzhardinge Message-ID: Cc: linux-kernel@vger.kernel.org, hpa@zytor.com, mingo@redhat.com, tglx@linutronix.de, hpa@linux.intel.com, jeremy.fitzhardinge@citrix.com Reply-To: mingo@redhat.com, hpa@zytor.com, linux-kernel@vger.kernel.org, tglx@linutronix.de, hpa@linux.intel.com, jeremy.fitzhardinge@citrix.com In-Reply-To: <11b6893703912054024bdb60251ed944f31cbafe.1308878118.git.jeremy.fitzhardinge@citrix.com> References: <11b6893703912054024bdb60251ed944f31cbafe.1308878118.git.jeremy.fitzhardinge@citrix.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/spinlocks] x86, ticketlock: Make __ticket_spin_lock common Git-Commit-ID: 65bd26616b53c5dfab162f18c34ec57ddb682a00 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Fri, 22 Jul 2011 19:57:25 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 65bd26616b53c5dfab162f18c34ec57ddb682a00 Gitweb: http://git.kernel.org/tip/65bd26616b53c5dfab162f18c34ec57ddb682a00 Author: Jeremy Fitzhardinge AuthorDate: Thu, 23 Jun 2011 18:19:17 -0700 Committer: H. Peter Anvin CommitDate: Fri, 22 Jul 2011 11:18:44 -0700 x86, ticketlock: Make __ticket_spin_lock common Aside from the particular form of the xadd instruction, they're identical. So factor out the xadd and use common code for the rest. Signed-off-by: Jeremy Fitzhardinge Link: http://lkml.kernel.org/r/11b6893703912054024bdb60251ed944f31cbafe.1308878118.git.jeremy.fitzhardinge@citrix.com Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/spinlock.h | 42 ++++++++++++++++++-------------------- 1 files changed, 20 insertions(+), 22 deletions(-) diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h index 078319e..a0e26c8 100644 --- a/arch/x86/include/asm/spinlock.h +++ b/arch/x86/include/asm/spinlock.h @@ -67,13 +67,27 @@ static __always_inline void __ticket_unlock_release(struct arch_spinlock *lock) * save some instructions and make the code more elegant. There really isn't * much between them in performance though, especially as locks are out of line. */ -#if (NR_CPUS < 256) -static __always_inline void __ticket_spin_lock(arch_spinlock_t *lock) +static __always_inline struct __raw_tickets __ticket_spin_claim(struct arch_spinlock *lock) { - register struct __raw_tickets inc = { .tail = 1 }; + register struct __raw_tickets tickets = { .tail = 1 }; + + if (sizeof(lock->tickets.head) == sizeof(u8)) + asm volatile (LOCK_PREFIX "xaddw %w0, %1\n" + : "+r" (tickets), "+m" (lock->tickets) + : : "memory", "cc"); + else + asm volatile (LOCK_PREFIX "xaddl %0, %1\n" + : "+r" (tickets), "+m" (lock->tickets) + : : "memory", "cc"); - asm volatile (LOCK_PREFIX "xaddw %w0, %1\n" - : "+r" (inc), "+m" (lock->tickets) : : "memory", "cc"); + return tickets; +} + +static __always_inline void __ticket_spin_lock(struct arch_spinlock *lock) +{ + register struct __raw_tickets inc; + + inc = __ticket_spin_claim(lock); for (;;) { if (inc.head == inc.tail) @@ -84,6 +98,7 @@ static __always_inline void __ticket_spin_lock(arch_spinlock_t *lock) out: barrier(); /* make sure nothing creeps before the lock is taken */ } +#if (NR_CPUS < 256) static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) { unsigned int tmp, new; @@ -103,23 +118,6 @@ static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) return tmp; } #else -static __always_inline void __ticket_spin_lock(arch_spinlock_t *lock) -{ - register struct __raw_tickets inc = { .tail = 1 }; - - asm volatile(LOCK_PREFIX "xaddl %0, %1\n\t" - : "+r" (inc), "+m" (lock->tickets) - : : "memory", "cc"); - - for (;;) { - if (inc.head == inc.tail) - goto out; - cpu_relax(); - inc.head = ACCESS_ONCE(lock->tickets.head); - } -out: barrier(); /* make sure nothing creeps before the lock is taken */ -} - static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) { unsigned tmp;