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Pull ticket4byte into release branch

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This commit is contained in:
Tony Luck 2009-10-23 17:58:54 -07:00
commit 48fade6c5a
2 changed files with 42 additions and 22 deletions
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62
arch/ia64/include/asm/spinlock.h
View File

@ -25,61 +25,82 @@
* by atomically noting the tail and incrementing it by one (thus adding
* ourself to the queue and noting our position), then waiting until the head
* becomes equal to the the initial value of the tail.
* The pad bits in the middle are used to prevent the next_ticket number
* overflowing into the now_serving number.
*
* 63 32 31 0
* 31 17 16 15 14 0
* +----------------------------------------------------+
* | next_ticket_number | now_serving |
* | now_serving | padding | next_ticket |
* +----------------------------------------------------+
*/
#define TICKET_SHIFT 32
#define TICKET_SHIFT 17
#define TICKET_BITS 15
#define TICKET_MASK ((1 << TICKET_BITS) - 1)
static __always_inline void __ticket_spin_lock(raw_spinlock_t *lock)
{
int *p = (int *)&lock->lock, turn, now_serving;
int *p = (int *)&lock->lock, ticket, serve;
now_serving = *p;
turn = ia64_fetchadd(1, p+1, acq);
ticket = ia64_fetchadd(1, p, acq);
if (turn == now_serving)
if (!(((ticket >> TICKET_SHIFT) ^ ticket) & TICKET_MASK))
return;
do {
ia64_invala();
for (;;) {
asm volatile ("ld4.c.nc %0=[%1]" : "=r"(serve) : "r"(p) : "memory");
if (!(((serve >> TICKET_SHIFT) ^ ticket) & TICKET_MASK))
return;
cpu_relax();
} while (ACCESS_ONCE(*p) != turn);
}
}
static __always_inline int __ticket_spin_trylock(raw_spinlock_t *lock)
{
long tmp = ACCESS_ONCE(lock->lock), try;
int tmp = ACCESS_ONCE(lock->lock);
if (!(((tmp >> TICKET_SHIFT) ^ tmp) & ((1L << TICKET_SHIFT) - 1))) {
try = tmp + (1L << TICKET_SHIFT);
return ia64_cmpxchg(acq, &lock->lock, tmp, try, sizeof (tmp)) == tmp;
}
if (!(((tmp >> TICKET_SHIFT) ^ tmp) & TICKET_MASK))
return ia64_cmpxchg(acq, &lock->lock, tmp, tmp + 1, sizeof (tmp)) == tmp;
return 0;
}
static __always_inline void __ticket_spin_unlock(raw_spinlock_t *lock)
{
int *p = (int *)&lock->lock;
unsigned short *p = (unsigned short *)&lock->lock + 1, tmp;
(void)ia64_fetchadd(1, p, rel);
asm volatile ("ld2.bias %0=[%1]" : "=r"(tmp) : "r"(p));
ACCESS_ONCE(*p) = (tmp + 2) & ~1;
}
static __always_inline void __ticket_spin_unlock_wait(raw_spinlock_t *lock)
{
int *p = (int *)&lock->lock, ticket;
ia64_invala();
for (;;) {
asm volatile ("ld4.c.nc %0=[%1]" : "=r"(ticket) : "r"(p) : "memory");
if (!(((ticket >> TICKET_SHIFT) ^ ticket) & TICKET_MASK))
return;
cpu_relax();
}
}
static inline int __ticket_spin_is_locked(raw_spinlock_t *lock)
{
long tmp = ACCESS_ONCE(lock->lock);
return !!(((tmp >> TICKET_SHIFT) ^ tmp) & ((1L << TICKET_SHIFT) - 1));
return !!(((tmp >> TICKET_SHIFT) ^ tmp) & TICKET_MASK);
}
static inline int __ticket_spin_is_contended(raw_spinlock_t *lock)
{
long tmp = ACCESS_ONCE(lock->lock);
return (((tmp >> TICKET_SHIFT) - tmp) & ((1L << TICKET_SHIFT) - 1)) > 1;
return ((tmp - (tmp >> TICKET_SHIFT)) & TICKET_MASK) > 1;
}
static inline int __raw_spin_is_locked(raw_spinlock_t *lock)
@ -116,8 +137,7 @@ static __always_inline void __raw_spin_lock_flags(raw_spinlock_t *lock,
static inline void __raw_spin_unlock_wait(raw_spinlock_t *lock)
{
while (__raw_spin_is_locked(lock))
cpu_relax();
__ticket_spin_unlock_wait(lock);
}
#define __raw_read_can_lock(rw) (*(volatile int *)(rw) >= 0)

2
arch/ia64/include/asm/spinlock_types.h
View File

@ -6,7 +6,7 @@
#endif
typedef struct {
volatile unsigned long lock;
volatile unsigned int lock;
} raw_spinlock_t;
#define __RAW_SPIN_LOCK_UNLOCKED { 0 }