From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755331Ab1GVT5J (ORCPT ); Fri, 22 Jul 2011 15:57:09 -0400 Received: from hera.kernel.org ([140.211.167.34]:38159 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751481Ab1GVT5H (ORCPT ); Fri, 22 Jul 2011 15:57:07 -0400 Date: Fri, 22 Jul 2011 19:57:01 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: <9eea42d16aabc7624488eb62213a763dbbacef38.1308878118.git.jeremy.fitzhardinge@citrix.com> References: <9eea42d16aabc7624488eb62213a763dbbacef38.1308878118.git.jeremy.fitzhardinge@citrix.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/spinlocks] x86, ticketlock: Make large and small ticket versions of spin_lock the same Git-Commit-ID: dc126c03ca25de516eaa8e575a98b81382d6d4b4 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 19:57:02 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: dc126c03ca25de516eaa8e575a98b81382d6d4b4 Gitweb: http://git.kernel.org/tip/dc126c03ca25de516eaa8e575a98b81382d6d4b4 Author: Jeremy Fitzhardinge AuthorDate: Thu, 23 Jun 2011 18:19:16 -0700 Committer: H. Peter Anvin CommitDate: Fri, 22 Jul 2011 11:18:37 -0700 x86, ticketlock: Make large and small ticket versions of spin_lock the same Make the bulk of __ticket_spin_lock look identical for large and small number of cpus. Signed-off-by: Jeremy Fitzhardinge Link: http://lkml.kernel.org/r/9eea42d16aabc7624488eb62213a763dbbacef38.1308878118.git.jeremy.fitzhardinge@citrix.com Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/spinlock.h | 23 ++++++++--------------- 1 files changed, 8 insertions(+), 15 deletions(-) diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h index f8d51dc..078319e 100644 --- a/arch/x86/include/asm/spinlock.h +++ b/arch/x86/include/asm/spinlock.h @@ -70,19 +70,16 @@ static __always_inline void __ticket_unlock_release(struct arch_spinlock *lock) #if (NR_CPUS < 256) static __always_inline void __ticket_spin_lock(arch_spinlock_t *lock) { - register union { - struct __raw_tickets tickets; - unsigned short slock; - } inc = { .slock = 1 << TICKET_SHIFT }; + register struct __raw_tickets inc = { .tail = 1 }; asm volatile (LOCK_PREFIX "xaddw %w0, %1\n" - : "+Q" (inc), "+m" (lock->slock) : : "memory", "cc"); + : "+r" (inc), "+m" (lock->tickets) : : "memory", "cc"); for (;;) { - if (inc.tickets.head == inc.tickets.tail) + if (inc.head == inc.tail) goto out; cpu_relax(); - inc.tickets.head = ACCESS_ONCE(lock->tickets.head); + inc.head = ACCESS_ONCE(lock->tickets.head); } out: barrier(); /* make sure nothing creeps before the lock is taken */ } @@ -108,21 +105,17 @@ static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) #else static __always_inline void __ticket_spin_lock(arch_spinlock_t *lock) { - unsigned inc = 1 << TICKET_SHIFT; - __ticket_t tmp; + register struct __raw_tickets inc = { .tail = 1 }; asm volatile(LOCK_PREFIX "xaddl %0, %1\n\t" - : "+r" (inc), "+m" (lock->slock) + : "+r" (inc), "+m" (lock->tickets) : : "memory", "cc"); - tmp = inc; - inc >>= TICKET_SHIFT; - for (;;) { - if ((__ticket_t)inc == tmp) + if (inc.head == inc.tail) goto out; cpu_relax(); - tmp = ACCESS_ONCE(lock->tickets.head); + inc.head = ACCESS_ONCE(lock->tickets.head); } out: barrier(); /* make sure nothing creeps before the lock is taken */ }