Messages in this thread Patch in this message | | | Date | Fri, 05 Sep 2008 13:28:11 +0100 | From | "Jan Beulich" <> | Subject | [PATCH 2/3] x86: ticket spin locks: factor out more common code |
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Signed-off-by: Jan Beulich <jbeulich@novell.com> Cc: Nick Piggin <npiggin@suse.de>
--- include/asm-x86/spinlock.h | 42 ++++++++++++++++-------------------------- 1 file changed, 16 insertions(+), 26 deletions(-)
--- linux-x86.orig/include/asm-x86/spinlock.h +++ linux-x86/include/asm-x86/spinlock.h @@ -54,19 +54,7 @@ * much between them in performance though, especially as locks are out of line. */ #if (NR_CPUS < 256) -static inline int __ticket_spin_is_locked(raw_spinlock_t *lock) -{ - int tmp = ACCESS_ONCE(lock->slock); - - return (((tmp >> 8) & 0xff) != (tmp & 0xff)); -} - -static inline int __ticket_spin_is_contended(raw_spinlock_t *lock) -{ - int tmp = ACCESS_ONCE(lock->slock); - - return (((tmp >> 8) - tmp) & 0xff) > 1; -} +#define TICKET_SHIFT 8 static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock) { @@ -116,19 +104,7 @@ static __always_inline void __ticket_spi : "memory", "cc"); } #else -static inline int __ticket_spin_is_locked(raw_spinlock_t *lock) -{ - int tmp = ACCESS_ONCE(lock->slock); - - return (((tmp >> 16) & 0xffff) != (tmp & 0xffff)); -} - -static inline int __ticket_spin_is_contended(raw_spinlock_t *lock) -{ - int tmp = ACCESS_ONCE(lock->slock); - - return (((tmp >> 16) - tmp) & 0xffff) > 1; -} +#define TICKET_SHIFT 16 static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock) { @@ -182,6 +158,20 @@ static __always_inline void __ticket_spi } #endif +static inline int __ticket_spin_is_locked(raw_spinlock_t *lock) +{ + int tmp = ACCESS_ONCE(lock->slock); + + return !!(((tmp >> TICKET_SHIFT) ^ tmp) & ((1 << TICKET_SHIFT) - 1)); +} + +static inline int __ticket_spin_is_contended(raw_spinlock_t *lock) +{ + int tmp = ACCESS_ONCE(lock->slock); + + return (((tmp >> TICKET_SHIFT) - tmp) & ((1 << TICKET_SHIFT) - 1)) > 1; +} + #ifdef CONFIG_PARAVIRT /* * Define virtualization-friendly old-style lock byte lock, for use in
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