From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755347Ab1GVT54 (ORCPT ); Fri, 22 Jul 2011 15:57:56 -0400 Received: from hera.kernel.org ([140.211.167.34]:38195 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754246Ab1GVT5y (ORCPT ); Fri, 22 Jul 2011 15:57:54 -0400 Date: Fri, 22 Jul 2011 19:57:48 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: <9ef9d6f621bda6e9052d908a39a9831345c34296.1308878118.git.jeremy.fitzhardinge@citrix.com> References: <9ef9d6f621bda6e9052d908a39a9831345c34296.1308878118.git.jeremy.fitzhardinge@citrix.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/spinlocks] x86, ticketlock: Make __ticket_spin_trylock common Git-Commit-ID: f5b00da7b60cc444b5e6caf2f08b0eebcebff75e 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 19:57:49 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: f5b00da7b60cc444b5e6caf2f08b0eebcebff75e Gitweb: http://git.kernel.org/tip/f5b00da7b60cc444b5e6caf2f08b0eebcebff75e Author: Jeremy Fitzhardinge AuthorDate: Thu, 23 Jun 2011 18:19:18 -0700 Committer: H. Peter Anvin CommitDate: Fri, 22 Jul 2011 11:18:53 -0700 x86, ticketlock: Make __ticket_spin_trylock common Make trylock code common regardless of ticket size. Signed-off-by: Jeremy Fitzhardinge Link: http://lkml.kernel.org/r/9ef9d6f621bda6e9052d908a39a9831345c34296.1308878118.git.jeremy.fitzhardinge@citrix.com Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/spinlock.h | 49 +++++++-------------------------- arch/x86/include/asm/spinlock_types.h | 6 +++- 2 files changed, 14 insertions(+), 41 deletions(-) diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h index a0e26c8..e07dc41 100644 --- a/arch/x86/include/asm/spinlock.h +++ b/arch/x86/include/asm/spinlock.h @@ -98,48 +98,19 @@ static __always_inline void __ticket_spin_lock(struct arch_spinlock *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; - - asm volatile("movzwl %2, %0\n\t" - "cmpb %h0,%b0\n\t" - "leal 0x100(%" REG_PTR_MODE "0), %1\n\t" - "jne 1f\n\t" - LOCK_PREFIX "cmpxchgw %w1,%2\n\t" - "1:" - "sete %b1\n\t" - "movzbl %b1,%0\n\t" - : "=&a" (tmp), "=&q" (new), "+m" (lock->slock) - : - : "memory", "cc"); - - return tmp; -} -#else -static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) -{ - unsigned tmp; - unsigned new; - - asm volatile("movl %2,%0\n\t" - "movl %0,%1\n\t" - "roll $16, %0\n\t" - "cmpl %0,%1\n\t" - "leal 0x00010000(%" REG_PTR_MODE "0), %1\n\t" - "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) - : - : "memory", "cc"); - - return tmp; + arch_spinlock_t old, new; + + old.tickets = ACCESS_ONCE(lock->tickets); + if (old.tickets.head != old.tickets.tail) + return 0; + + new.head_tail = old.head_tail + (1 << TICKET_SHIFT); + + /* cmpxchg is a full barrier, so nothing can move before it */ + return cmpxchg(&lock->head_tail, old.head_tail, new.head_tail) == old.head_tail; } -#endif static __always_inline void __ticket_spin_unlock(arch_spinlock_t *lock) { diff --git a/arch/x86/include/asm/spinlock_types.h b/arch/x86/include/asm/spinlock_types.h index e3ad1e3..72e154e 100644 --- a/arch/x86/include/asm/spinlock_types.h +++ b/arch/x86/include/asm/spinlock_types.h @@ -9,8 +9,10 @@ #if (CONFIG_NR_CPUS < 256) typedef u8 __ticket_t; +typedef u16 __ticketpair_t; #else typedef u16 __ticket_t; +typedef u32 __ticketpair_t; #endif #define TICKET_SHIFT (sizeof(__ticket_t) * 8) @@ -18,14 +20,14 @@ typedef u16 __ticket_t; typedef struct arch_spinlock { union { - unsigned int slock; + __ticketpair_t head_tail; struct __raw_tickets { __ticket_t head, tail; } tickets; }; } arch_spinlock_t; -#define __ARCH_SPIN_LOCK_UNLOCKED { { .slock = 0 } } +#define __ARCH_SPIN_LOCK_UNLOCKED { { 0 } } typedef struct { unsigned int lock;