Commit-ID: bd01ec1a13f9a327950c8e3080096446c7804753 Gitweb: http://git.kernel.org/tip/bd01ec1a13f9a327950c8e3080096446c7804753 Author: Waiman Long <waiman.l...@hp.com> AuthorDate: Mon, 3 Feb 2014 13:18:57 +0100 Committer: Ingo Molnar <mi...@kernel.org> CommitDate: Fri, 6 Jun 2014 07:58:29 +0200
x86, locking/rwlocks: Enable qrwlocks on x86 Make x86 use the fair rwlock_t. Implement the custom queue_write_unlock() for best performance. Signed-off-by: Waiman Long <waiman.l...@hp.com> [peterz: near complete rewrite] Signed-off-by: Peter Zijlstra <pet...@infradead.org> Cc: Dave Jones <da...@redhat.com> Cc: Jeremy Fitzhardinge <jer...@goop.org> Cc: Konrad Rzeszutek Wilk <konrad.w...@oracle.com> Cc: Linus Torvalds <torva...@linux-foundation.org> Cc: Oleg Nesterov <o...@redhat.com> Cc: Raghavendra K T <raghavendra...@linux.vnet.ibm.com> Cc: "Paul E.McKenney" <paul...@linux.vnet.ibm.com> Cc: linux-kernel@vger.kernel.org Cc: x...@kernel.org Link: http://lkml.kernel.org/n/tip-r1xuzmdysvuhl3h86n5fb...@git.kernel.org Signed-off-by: Ingo Molnar <mi...@kernel.org> --- arch/x86/Kconfig | 1 + arch/x86/include/asm/qrwlock.h | 17 +++++++++++++++++ arch/x86/include/asm/spinlock.h | 4 ++++ arch/x86/include/asm/spinlock_types.h | 4 ++++ 4 files changed, 26 insertions(+) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 25d2c6f..bf7626f 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -121,6 +121,7 @@ config X86 select MODULES_USE_ELF_RELA if X86_64 select CLONE_BACKWARDS if X86_32 select ARCH_USE_BUILTIN_BSWAP + select ARCH_USE_QUEUE_RWLOCK select OLD_SIGSUSPEND3 if X86_32 || IA32_EMULATION select OLD_SIGACTION if X86_32 select COMPAT_OLD_SIGACTION if IA32_EMULATION diff --git a/arch/x86/include/asm/qrwlock.h b/arch/x86/include/asm/qrwlock.h new file mode 100644 index 0000000..70f46f0 --- /dev/null +++ b/arch/x86/include/asm/qrwlock.h @@ -0,0 +1,17 @@ +#ifndef _ASM_X86_QRWLOCK_H +#define _ASM_X86_QRWLOCK_H + +#include <asm-generic/qrwlock_types.h> + +#if !defined(CONFIG_X86_OOSTORE) && !defined(CONFIG_X86_PPRO_FENCE) +#define queue_write_unlock queue_write_unlock +static inline void queue_write_unlock(struct qrwlock *lock) +{ + barrier(); + ACCESS_ONCE(*(u8 *)&lock->cnts) = 0; +} +#endif + +#include <asm-generic/qrwlock.h> + +#endif /* _ASM_X86_QRWLOCK_H */ diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h index 0f62f54..54f1c80 100644 --- a/arch/x86/include/asm/spinlock.h +++ b/arch/x86/include/asm/spinlock.h @@ -187,6 +187,7 @@ static inline void arch_spin_unlock_wait(arch_spinlock_t *lock) cpu_relax(); } +#ifndef CONFIG_QUEUE_RWLOCK /* * Read-write spinlocks, allowing multiple readers * but only one writer. @@ -269,6 +270,9 @@ static inline void arch_write_unlock(arch_rwlock_t *rw) asm volatile(LOCK_PREFIX WRITE_LOCK_ADD(%1) "%0" : "+m" (rw->write) : "i" (RW_LOCK_BIAS) : "memory"); } +#else +#include <asm/qrwlock.h> +#endif /* CONFIG_QUEUE_RWLOCK */ #define arch_read_lock_flags(lock, flags) arch_read_lock(lock) #define arch_write_lock_flags(lock, flags) arch_write_lock(lock) diff --git a/arch/x86/include/asm/spinlock_types.h b/arch/x86/include/asm/spinlock_types.h index 4f1bea1..73c4c00 100644 --- a/arch/x86/include/asm/spinlock_types.h +++ b/arch/x86/include/asm/spinlock_types.h @@ -34,6 +34,10 @@ typedef struct arch_spinlock { #define __ARCH_SPIN_LOCK_UNLOCKED { { 0 } } +#ifdef CONFIG_QUEUE_RWLOCK +#include <asm-generic/qrwlock_types.h> +#else #include <asm/rwlock.h> +#endif #endif /* _ASM_X86_SPINLOCK_TYPES_H */ -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
