x86, pvticketlock: When paravirtualizing ticket locks, increment by 2

[cascardo/linux.git] / arch / x86 / include / asm / spinlock.h

diff --git a/arch/x86/include/asm/spinlock.h b/arch/x86/include/asm/spinlock.h
index 7442410..04a5cd5 100644 (file)
--- a/arch/x86/include/asm/spinlock.h
+++ b/arch/x86/include/asm/spinlock.h
@@ -78,7 +78,7 @@ static __always_inline void __ticket_unlock_kick(struct arch_spinlock *lock,
  */
 static __always_inline void arch_spin_lock(struct arch_spinlock *lock)
 {
-       register struct __raw_tickets inc = { .tail = 1 };
+       register struct __raw_tickets inc = { .tail = TICKET_LOCK_INC };
 
        inc = xadd(&lock->tickets, inc);
 
@@ -104,7 +104,7 @@ static __always_inline int arch_spin_trylock(arch_spinlock_t *lock)
        if (old.tickets.head != old.tickets.tail)
                return 0;
 
-       new.head_tail = old.head_tail + (1 << TICKET_SHIFT);
+       new.head_tail = old.head_tail + (TICKET_LOCK_INC << TICKET_SHIFT);
 
        /* cmpxchg is a full barrier, so nothing can move before it */
        return cmpxchg(&lock->head_tail, old.head_tail, new.head_tail) == old.head_tail;
@@ -112,9 +112,9 @@ static __always_inline int arch_spin_trylock(arch_spinlock_t *lock)
 
 static __always_inline void arch_spin_unlock(arch_spinlock_t *lock)
 {
-       __ticket_t next = lock->tickets.head + 1;
+       __ticket_t next = lock->tickets.head + TICKET_LOCK_INC;
 
-       __add(&lock->tickets.head, 1, UNLOCK_LOCK_PREFIX);
+       __add(&lock->tickets.head, TICKET_LOCK_INC, UNLOCK_LOCK_PREFIX);
        __ticket_unlock_kick(lock, next);
 }
 
@@ -129,7 +129,7 @@ static inline int arch_spin_is_contended(arch_spinlock_t *lock)
 {
        struct __raw_tickets tmp = ACCESS_ONCE(lock->tickets);
 
-       return (__ticket_t)(tmp.tail - tmp.head) > 1;
+       return (__ticket_t)(tmp.tail - tmp.head) > TICKET_LOCK_INC;
 }
 #define arch_spin_is_contended arch_spin_is_contended