volatile qnode * hclh_acquire(local_queue *lq, global_queue *gq, qnode *my_qnode) {
volatile qnode* my_pred;
do
{
#if defined(OPTERON_OPTIMIZE)
PREFETCHW(lq);
#endif /* OPTERON_OPTIMIZE */
my_pred = *lq;
} while (CAS_PTR(lq, my_pred, my_qnode)!=my_pred);
if (my_pred != NULL)
{
uint16_t i_own_lock = wait_for_grant_or_cluster_master(my_pred, my_qnode->fields.cluster_id);
if (i_own_lock)
{
return my_pred;
}
}
PAUSE; PAUSE;
volatile qnode * local_tail;
do
{
#if defined(OPTERON_OPTIMIZE)
PREFETCHW(gq);
PREFETCHW(lq);
#endif /* OPTERON_OPTIMIZE */
my_pred = *gq;
local_tail = *lq;
PAUSE;
} while(CAS_PTR(gq, my_pred, local_tail)!=my_pred);
local_tail->fields.tail_when_spliced = 1;
#if defined(OPTERON_OPTIMIZE)
PREFETCHW(my_pred);
#endif /* OPTERON_OPTIMIZE */
while (my_pred->fields.successor_must_wait) {
PAUSE;
#if defined(OPTERON_OPTIMIZE)
pause_rep(23);
PREFETCHW(my_pred);
#endif /* OPTERON_OPTIMIZE */
}
return my_pred;
}
volatile qnode * hclh_acquire(local_queue *lq, global_queue *gq, qnode *my_qnode) {
//splice my_qnode into local queue
volatile qnode* my_pred;
do
{
my_pred = *lq;
} while (CAS_PTR(lq, my_pred, my_qnode)!=my_pred);
if (my_pred != NULL)
{
uint16_t i_own_lock = wait_for_grant_or_cluster_master(my_pred, my_qnode->fields.cluster_id);
if (i_own_lock)
{
//I have the lock; return qnode just released by previous owner
return my_pred;
}
}
//at this point, I'm cluster master. Wait to allow time for other acquireres to show up.
PAUSE; PAUSE;
volatile qnode * local_tail;
//splice local queue into global queue
do
{
my_pred = *gq;
local_tail = *lq;
PAUSE;
} while(CAS_PTR(gq, my_pred, local_tail)!=my_pred);
//inform successor that it is the new master
local_tail->fields.tail_when_spliced = 1;
//wait for predecessor to release lock
while (my_pred->fields.successor_must_wait) {
PAUSE;
}
//I have the lock. return qnode just released by previous owner for next lock access
return my_pred;
}
