diff options
Diffstat (limited to 'src/thread/pthread_barrier_wait.c')
| -rw-r--r-- | src/thread/pthread_barrier_wait.c | 16 |
1 files changed, 12 insertions, 4 deletions
diff --git a/src/thread/pthread_barrier_wait.c b/src/thread/pthread_barrier_wait.c index a97f6d56..9b1edbf9 100644 --- a/src/thread/pthread_barrier_wait.c +++ b/src/thread/pthread_barrier_wait.c @@ -23,11 +23,12 @@ static int pshared_barrier_wait(pthread_barrier_t *b) int limit = (b->_b_limit & INT_MAX) + 1; int seq; int ret = 0; + int v, w; if (limit==1) return PTHREAD_BARRIER_SERIAL_THREAD; - while (a_swap(&b->_b_lock, 1)) - __wait(&b->_b_lock, &b->_b_waiters, 1, 0); + while ((v=a_cas(&b->_b_lock, 0, limit))) + __wait(&b->_b_lock, &b->_b_waiters, v, 0); seq = b->_b_seq; @@ -46,12 +47,19 @@ static int pshared_barrier_wait(pthread_barrier_t *b) if (a_fetch_add(&b->_b_count, -1)==1) { b->_b_seq++; __wake(&b->_b_seq, -1, 0); - a_store(&b->_b_lock, 0); - if (b->_b_waiters) __wake(&b->_b_lock, 1, 0); } else { __wait(&b->_b_seq, 0, seq+1, 0); } + /* Perform a recursive unlock suitable for self-sync'd destruction */ + do { + v = b->_b_lock; + w = b->_b_waiters; + } while (a_cas(&b->_b_lock, v, v-1 & INT_MAX) != v); + + if (v==INT_MIN+1 || (v==1 && w)) + __wake(&b->_b_lock, 1, 0); + __vm_unlock(); return ret; |