[PATCH RFC 03/12] x86/ticketlock: Use C for __ticket_spin_unlock
in [Kernel]
|
Prev: [PATCH RFC 12/12] x86/pvticketlock: use callee-save for unlock_kick as well
Next: [PATCH RFC 08/12] x86/ticketlock: collapse a layer of functions
From: Jeremy Fitzhardinge on 16 Jul 2010 21:00 If we don't need to use a locked inc for unlock, then implement it in C. Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge(a)citrix.com> --- arch/x86/include/asm/spinlock.h | 33 ++++++++++++++++++--------------- 1 files changed, 18 insertions(+), 15 deletions(-) diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h index 6711d36..082990a 100644 --- a/arch/x86/include/asm/spinlock.h +++ b/arch/x86/include/asm/spinlock.h @@ -33,9 +33,23 @@ * On PPro SMP or if we are using OOSTORE, we use a locked operation to unlock * (PPro errata 66, 92) */ -# define UNLOCK_LOCK_PREFIX LOCK_PREFIX +static __always_inline void __ticket_unlock_release(struct arch_spinlock *lock) +{ + if (sizeof(lock->tickets.head) == sizeof(u8)) + asm (LOCK_PREFIX "incb %0" + : "+m" (lock->tickets.head) : : "memory"); + else + asm (LOCK_PREFIX "incw %0" + : "+m" (lock->tickets.head) : : "memory"); + +} #else -# define UNLOCK_LOCK_PREFIX +static __always_inline void __ticket_unlock_release(struct arch_spinlock *lock) +{ + barrier(); + lock->tickets.head++; + barrier(); +} #endif /* @@ -93,14 +107,6 @@ static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) return tmp; } - -static __always_inline void __ticket_spin_unlock(arch_spinlock_t *lock) -{ - asm volatile(UNLOCK_LOCK_PREFIX "incb %0" - : "+m" (lock->slock) - : - : "memory", "cc"); -} #else static __always_inline void __ticket_spin_lock(arch_spinlock_t *lock) { @@ -144,15 +150,12 @@ static __always_inline int __ticket_spin_trylock(arch_spinlock_t *lock) return tmp; } +#endif static __always_inline void __ticket_spin_unlock(arch_spinlock_t *lock) { - asm volatile(UNLOCK_LOCK_PREFIX "incw %0" - : "+m" (lock->slock) - : - : "memory", "cc"); + __ticket_unlock_release(lock); } -#endif static inline int __ticket_spin_is_locked(arch_spinlock_t *lock) { -- 1.7.1.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo(a)vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/ |