From patchwork Wed May 7 15:01:30 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Waiman Long X-Patchwork-Id: 4129481 Return-Path: X-Original-To: patchwork-kvm@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.19.201]) by patchwork2.web.kernel.org (Postfix) with ESMTP id C4048BFF02 for ; Wed, 7 May 2014 15:09:42 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id D80BF20179 for ; Wed, 7 May 2014 15:09:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E8E3720176 for ; Wed, 7 May 2014 15:09:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756415AbaEGPCg (ORCPT ); Wed, 7 May 2014 11:02:36 -0400 Received: from g4t3426.houston.hp.com ([15.201.208.54]:9922 "EHLO g4t3426.houston.hp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755934AbaEGPCe (ORCPT ); Wed, 7 May 2014 11:02:34 -0400 Received: from g9t2301.houston.hp.com (g9t2301.houston.hp.com [16.216.185.78]) by g4t3426.houston.hp.com (Postfix) with ESMTP id 5EEDF1C8; Wed, 7 May 2014 15:02:34 +0000 (UTC) Received: from RHEL65.localdomain (unknown [16.99.26.141]) by g9t2301.houston.hp.com (Postfix) with ESMTP id A551F6C; Wed, 7 May 2014 15:02:32 +0000 (UTC) From: Waiman Long To: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Peter Zijlstra Cc: linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, virtualization@lists.linux-foundation.org, xen-devel@lists.xenproject.org, kvm@vger.kernel.org, Paolo Bonzini , Konrad Rzeszutek Wilk , Boris Ostrovsky , "Paul E. McKenney" , Rik van Riel , Linus Torvalds , Raghavendra K T , David Vrabel , Oleg Nesterov , Gleb Natapov , Scott J Norton , Chegu Vinod , Waiman Long , Peter Zijlstra Subject: [PATCH v10 02/19] qspinlock, x86: Enable x86-64 to use queue spinlock Date: Wed, 7 May 2014 11:01:30 -0400 Message-Id: <1399474907-22206-3-git-send-email-Waiman.Long@hp.com> X-Mailer: git-send-email 1.7.1 In-Reply-To: <1399474907-22206-1-git-send-email-Waiman.Long@hp.com> References: <1399474907-22206-1-git-send-email-Waiman.Long@hp.com> Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org X-Spam-Status: No, score=-7.5 required=5.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, RP_MATCHES_RCVD, UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP This patch makes the necessary changes at the x86 architecture specific layer to enable the use of queue spinlock for x86-64. As x86-32 machines are typically not multi-socket. The benefit of queue spinlock may not be apparent. So queue spinlock is not enabled. Currently, there is some incompatibilities between the para-virtualized spinlock code (which hard-codes the use of ticket spinlock) and the queue spinlock. Therefore, the use of queue spinlock is disabled when the para-virtualized spinlock is enabled. The arch/x86/include/asm/qspinlock.h header file includes some x86 specific optimization which will make the queue spinlock code perform better than the generic implementation. Signed-off-by: Waiman Long Signed-off-by: Peter Zijlstra --- arch/x86/Kconfig | 1 + arch/x86/include/asm/qspinlock.h | 29 +++++++++++++++++++++++++++++ arch/x86/include/asm/spinlock.h | 5 +++++ arch/x86/include/asm/spinlock_types.h | 4 ++++ 4 files changed, 39 insertions(+), 0 deletions(-) create mode 100644 arch/x86/include/asm/qspinlock.h diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 25d2c6f..95c9c4e 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -29,6 +29,7 @@ config X86 select ARCH_SUPPORTS_NUMA_BALANCING select ARCH_SUPPORTS_INT128 if X86_64 select ARCH_WANTS_PROT_NUMA_PROT_NONE + select ARCH_USE_QUEUE_SPINLOCK select HAVE_IDE select HAVE_OPROFILE select HAVE_PCSPKR_PLATFORM diff --git a/arch/x86/include/asm/qspinlock.h b/arch/x86/include/asm/qspinlock.h new file mode 100644 index 0000000..e4a4f5d --- /dev/null +++ b/arch/x86/include/asm/qspinlock.h @@ -0,0 +1,29 @@ +#ifndef _ASM_X86_QSPINLOCK_H +#define _ASM_X86_QSPINLOCK_H + +#include + +#if !defined(CONFIG_X86_OOSTORE) && !defined(CONFIG_X86_PPRO_FENCE) + +#define queue_spin_unlock queue_spin_unlock +/** + * queue_spin_unlock - release a queue spinlock + * @lock : Pointer to queue spinlock structure + * + * No special memory barrier other than a compiler one is needed for the + * x86 architecture. A compiler barrier is added at the end to make sure + * that the clearing the lock bit is done ASAP without artificial delay + * due to compiler optimization. + */ +static inline void queue_spin_unlock(struct qspinlock *lock) +{ + barrier(); + ACCESS_ONCE(*(u8 *)lock) = 0; + barrier(); +} + +#endif /* !CONFIG_X86_OOSTORE && !CONFIG_X86_PPRO_FENCE */ + +#include + +#endif /* _ASM_X86_QSPINLOCK_H */ diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h index 0f62f54..958d20f 100644 --- a/arch/x86/include/asm/spinlock.h +++ b/arch/x86/include/asm/spinlock.h @@ -42,6 +42,10 @@ extern struct static_key paravirt_ticketlocks_enabled; static __always_inline bool static_key_false(struct static_key *key); +#ifdef CONFIG_QUEUE_SPINLOCK +#include +#else + #ifdef CONFIG_PARAVIRT_SPINLOCKS static inline void __ticket_enter_slowpath(arch_spinlock_t *lock) @@ -180,6 +184,7 @@ static __always_inline void arch_spin_lock_flags(arch_spinlock_t *lock, { arch_spin_lock(lock); } +#endif /* CONFIG_QUEUE_SPINLOCK */ static inline void arch_spin_unlock_wait(arch_spinlock_t *lock) { diff --git a/arch/x86/include/asm/spinlock_types.h b/arch/x86/include/asm/spinlock_types.h index 4f1bea1..7960268 100644 --- a/arch/x86/include/asm/spinlock_types.h +++ b/arch/x86/include/asm/spinlock_types.h @@ -23,6 +23,9 @@ typedef u32 __ticketpair_t; #define TICKET_SHIFT (sizeof(__ticket_t) * 8) +#ifdef CONFIG_QUEUE_SPINLOCK +#include +#else typedef struct arch_spinlock { union { __ticketpair_t head_tail; @@ -33,6 +36,7 @@ typedef struct arch_spinlock { } arch_spinlock_t; #define __ARCH_SPIN_LOCK_UNLOCKED { { 0 } } +#endif /* CONFIG_QUEUE_SPINLOCK */ #include