From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755245Ab1GVTz2 (ORCPT ); Fri, 22 Jul 2011 15:55:28 -0400 Received: from hera.kernel.org ([140.211.167.34]:40627 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755008Ab1GVTz1 (ORCPT ); Fri, 22 Jul 2011 15:55:27 -0400 Date: Fri, 22 Jul 2011 19:55:19 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: <05552e1c97739f589cb76c20b5a6565ccd506636.1308878118.git.jeremy.fitzhardinge@citrix.com> References: <05552e1c97739f589cb76c20b5a6565ccd506636.1308878118.git.jeremy.fitzhardinge@citrix.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/spinlocks] x86, ticketlock: Clean up types and accessors Git-Commit-ID: 699f3dd4e4f8fba6ded83a3dc21e3db960323fcc 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 19:55:20 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 699f3dd4e4f8fba6ded83a3dc21e3db960323fcc Gitweb: http://git.kernel.org/tip/699f3dd4e4f8fba6ded83a3dc21e3db960323fcc Author: Jeremy Fitzhardinge AuthorDate: Thu, 23 Jun 2011 18:19:13 -0700 Committer: H. Peter Anvin CommitDate: Fri, 22 Jul 2011 11:13:17 -0700 x86, ticketlock: Clean up types and accessors A few cleanups to the way spinlocks are defined and accessed: - define __ticket_t which is the size of a spinlock ticket (ie, enough bits to hold all the cpus) - Define struct arch_spinlock as a union containing plain slock and the head and tail tickets - Use head and tail to implement some of the spinlock predicates. - Make all ticket variables unsigned. - Use TICKET_SHIFT to form constants Most of this will be used in later patches. Signed-off-by: Jeremy Fitzhardinge Link: http://lkml.kernel.org/r/05552e1c97739f589cb76c20b5a6565ccd506636.1308878118.git.jeremy.fitzhardinge@citrix.com Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/spinlock.h | 24 ++++++++++-------------- arch/x86/include/asm/spinlock_types.h | 20 ++++++++++++++++++-- 2 files changed, 28 insertions(+), 16 deletions(-) diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h index 3089f70..d6d5784 100644 --- a/arch/x86/include/asm/spinlock.h +++ b/arch/x86/include/asm/spinlock.h @@ -56,11 +56,9 @@ * much between them in performance though, especially as locks are out of line. */ #if (NR_CPUS < 256) -#define TICKET_SHIFT 8 - static __always_inline void __ticket_spin_lock(arch_spinlock_t *lock) { - short inc = 0x0100; + unsigned short inc = 1 << TICKET_SHIFT; asm volatile ( LOCK_PREFIX "xaddw %w0, %1\n" @@ -79,7 +77,7 @@ static __always_inline void __ticket_spin_lock(arch_spinlock_t *lock) static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) { - int tmp, new; + unsigned int tmp, new; asm volatile("movzwl %2, %0\n\t" "cmpb %h0,%b0\n\t" @@ -104,12 +102,10 @@ static __always_inline void __ticket_spin_unlock(arch_spinlock_t *lock) : "memory", "cc"); } #else -#define TICKET_SHIFT 16 - static __always_inline void __ticket_spin_lock(arch_spinlock_t *lock) { - int inc = 0x00010000; - int tmp; + unsigned inc = 1 << TICKET_SHIFT; + unsigned tmp; asm volatile(LOCK_PREFIX "xaddl %0, %1\n" "movzwl %w0, %2\n\t" @@ -129,8 +125,8 @@ static __always_inline void __ticket_spin_lock(arch_spinlock_t *lock) static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) { - int tmp; - int new; + unsigned tmp; + unsigned new; asm volatile("movl %2,%0\n\t" "movl %0,%1\n\t" @@ -160,16 +156,16 @@ static __always_inline void __ticket_spin_unlock(arch_spinlock_t *lock) static inline int __ticket_spin_is_locked(arch_spinlock_t *lock) { - int tmp = ACCESS_ONCE(lock->slock); + struct __raw_tickets tmp = ACCESS_ONCE(lock->tickets); - return !!(((tmp >> TICKET_SHIFT) ^ tmp) & ((1 << TICKET_SHIFT) - 1)); + return !!(tmp.tail ^ tmp.head); } static inline int __ticket_spin_is_contended(arch_spinlock_t *lock) { - int tmp = ACCESS_ONCE(lock->slock); + struct __raw_tickets tmp = ACCESS_ONCE(lock->tickets); - return (((tmp >> TICKET_SHIFT) - tmp) & ((1 << TICKET_SHIFT) - 1)) > 1; + return ((tmp.tail - tmp.head) & TICKET_MASK) > 1; } #ifndef CONFIG_PARAVIRT_SPINLOCKS diff --git a/arch/x86/include/asm/spinlock_types.h b/arch/x86/include/asm/spinlock_types.h index dcb48b2..e3ad1e3 100644 --- a/arch/x86/include/asm/spinlock_types.h +++ b/arch/x86/include/asm/spinlock_types.h @@ -5,11 +5,27 @@ # error "please don't include this file directly" #endif +#include + +#if (CONFIG_NR_CPUS < 256) +typedef u8 __ticket_t; +#else +typedef u16 __ticket_t; +#endif + +#define TICKET_SHIFT (sizeof(__ticket_t) * 8) +#define TICKET_MASK ((__ticket_t)((1 << TICKET_SHIFT) - 1)) + typedef struct arch_spinlock { - unsigned int slock; + union { + unsigned int slock; + struct __raw_tickets { + __ticket_t head, tail; + } tickets; + }; } arch_spinlock_t; -#define __ARCH_SPIN_LOCK_UNLOCKED { 0 } +#define __ARCH_SPIN_LOCK_UNLOCKED { { .slock = 0 } } typedef struct { unsigned int lock;