diff options
| author | Waiman Long <Waiman.Long@hp.com> | 2014-02-03 12:18:57 (GMT) |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-06-06 05:58:29 (GMT) |
| commit | bd01ec1a13f9a327950c8e3080096446c7804753 (patch) | |
| tree | 5af212f946ee023fdbadc9b14ff9e2a1431a0c72 | |
| parent | 70af2f8a4f48d6cebdf92d533d3aef37853ce6de (diff) | |
| download | linux-bd01ec1a13f9a327950c8e3080096446c7804753.tar.xz | |
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.Long@hp.com>
[peterz: near complete rewrite]
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Cc: Dave Jones <davej@redhat.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Raghavendra K T <raghavendra.kt@linux.vnet.ibm.com>
Cc: "Paul E.McKenney" <paulmck@linux.vnet.ibm.com>
Cc: linux-kernel@vger.kernel.org
Cc: x86@kernel.org
Link: http://lkml.kernel.org/n/tip-r1xuzmdysvuhl3h86n5fbxi7@git.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
| -rw-r--r-- | arch/x86/Kconfig | 1 | ||||
| -rw-r--r-- | arch/x86/include/asm/qrwlock.h | 17 | ||||
| -rw-r--r-- | arch/x86/include/asm/spinlock.h | 4 | ||||
| -rw-r--r-- | arch/x86/include/asm/spinlock_types.h | 4 |
4 files changed, 26 insertions, 0 deletions
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 */ |