arch/tile: use atomic exchange in arch_write_unlock()

This idiom is used elsewhere when we do an unlock by writing a zero,
but I missed it here.  Using an atomic operation avoids waiting
on the write buffer for the unlocking write to be sent to the home cache.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
This commit is contained in:
Chris Metcalf 2012-03-30 15:46:29 -04:00
parent b14f219067
commit ab306cae66

View File

@ -137,7 +137,7 @@ static inline void arch_read_unlock(arch_rwlock_t *rw)
static inline void arch_write_unlock(arch_rwlock_t *rw)
{
__insn_mf();
rw->lock = 0;
__insn_exch4(&rw->lock, 0); /* Avoid waiting in the write buffer. */
}
static inline int arch_read_trylock(arch_rwlock_t *rw)