void
sgen_workers_join (void)
{
State old_state;
int i;
if (!collection_needs_workers ())
return;
for (;;) {
old_state = workers_state;
SGEN_ASSERT (0, old_state.data.state != STATE_NURSERY_COLLECTION, "Can't be in nursery collection when joining");
if (old_state.data.state == STATE_WORKING) {
State new_state = old_state;
SGEN_ASSERT (0, !old_state.data.post_done, "Why is post_done already set?");
new_state.data.post_done = 1;
if (!set_state (old_state, new_state))
continue;
MONO_SEM_WAIT (&workers_done_sem);
old_state = workers_state;
}
assert_not_working (old_state);
/*
* Checking whether there is still work left and, if not, going to sleep,
* are two separate actions that are not performed atomically by the
* workers. Therefore there's a race condition where work can be added
* after they've checked for work, and before they've gone to sleep.
*/
if (!workers_job_queue_num_entries && sgen_section_gray_queue_is_empty (&workers_distribute_gray_queue))
break;
workers_signal_enqueue_work (workers_num, FALSE);
}
/* At this point all the workers have stopped. */
if (sgen_get_major_collector ()->reset_worker_data) {
for (i = 0; i < workers_num; ++i)
sgen_get_major_collector ()->reset_worker_data (workers_data [i].major_collector_data);
}
g_assert (workers_job_queue_num_entries == 0);
g_assert (sgen_section_gray_queue_is_empty (&workers_distribute_gray_queue));
for (i = 0; i < workers_num; ++i)
g_assert (sgen_gray_object_queue_is_empty (&workers_data [i].private_gray_queue));
}
static void
init_distribute_gray_queue (void)
{
if (workers_distribute_gray_queue_inited) {
g_assert (sgen_section_gray_queue_is_empty (&workers_distribute_gray_queue));
g_assert (workers_distribute_gray_queue.locked);
return;
}
sgen_section_gray_queue_init (&workers_distribute_gray_queue, TRUE,
sgen_get_major_collector ()->is_concurrent ? concurrent_enqueue_check : NULL);
workers_distribute_gray_queue_inited = TRUE;
}
void
sgen_section_gray_queue_init (SgenSectionGrayQueue *queue, gboolean locked, GrayQueueEnqueueCheckFunc enqueue_check_func)
{
g_assert (sgen_section_gray_queue_is_empty (queue));
queue->locked = locked;
if (locked) {
mono_os_mutex_init_recursive (&queue->lock);
}
#ifdef SGEN_CHECK_GRAY_OBJECT_ENQUEUE
queue->enqueue_check_func = enqueue_check_func;
#endif
}
void
sgen_workers_join (void)
{
int i;
sgen_thread_pool_wait_for_all_jobs ();
sgen_thread_pool_idle_wait ();
SGEN_ASSERT (0, workers_state == STATE_NOT_WORKING, "Can only signal enqueue work when in no work state");
/* At this point all the workers have stopped. */
SGEN_ASSERT (0, sgen_section_gray_queue_is_empty (&workers_distribute_gray_queue), "Why is there still work left to do?");
for (i = 0; i < workers_num; ++i)
SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&workers_data [i].private_gray_queue), "Why is there still work left to do?");
}
/*
* Can only be called if the workers are stopped.
* If we're stopped, there are also no pending jobs.
*/
gboolean
sgen_workers_have_idle_work (void)
{
int i;
SGEN_ASSERT (0, forced_stop && sgen_workers_all_done (), "Checking for idle work should only happen if the workers are stopped.");
if (!sgen_section_gray_queue_is_empty (&workers_distribute_gray_queue))
return TRUE;
for (i = 0; i < workers_num; ++i) {
if (!sgen_gray_object_queue_is_empty (&workers_data [i].private_gray_queue))
return TRUE;
}
return FALSE;
}
void
sgen_workers_join (void)
{
State old_state, new_state;
int i;
if (!collection_needs_workers ())
return;
do {
old_state = new_state = workers_state;
g_assert (old_state.data.gc_in_progress);
g_assert (!old_state.data.done_posted);
new_state.data.gc_in_progress = 0;
} while (!set_state (old_state, new_state));
if (new_state.data.num_waiting == workers_num) {
/*
* All the workers have shut down but haven't posted
* the done semaphore yet, or, if we come from below,
* haven't done all their work yet.
*
* It's not a big deal to wake them up again - they'll
* just do one iteration of their loop trying to find
* something to do and then go back to waiting again.
*/
reawaken:
workers_wake_up_all ();
}
MONO_SEM_WAIT (&workers_done_sem);
old_state = new_state = workers_state;
g_assert (old_state.data.num_waiting == workers_num);
g_assert (old_state.data.done_posted);
if (workers_job_queue_num_entries || !sgen_section_gray_queue_is_empty (&workers_distribute_gray_queue)) {
/*
* There's a small race condition that we avoid here.
* It's possible that a worker thread runs out of
* things to do, so it goes to sleep. Right at that
* moment a new job is enqueued, but the thread is
* still registered as running. Now the threads are
* joined, and we wait for the semaphore. Only at
* this point does the worker go to sleep, and posts
* the semaphore, because workers_gc_in_progress is
* already FALSE. The job is still in the queue,
* though.
*
* Clear the done posted flag.
*/
new_state.data.done_posted = 0;
if (!set_state (old_state, new_state))
g_assert_not_reached ();
goto reawaken;
}
/* At this point all the workers have stopped. */
workers_marking = FALSE;
if (sgen_get_major_collector ()->reset_worker_data) {
for (i = 0; i < workers_num; ++i)
sgen_get_major_collector ()->reset_worker_data (workers_data [i].major_collector_data);
}
g_assert (workers_job_queue_num_entries == 0);
g_assert (sgen_section_gray_queue_is_empty (&workers_distribute_gray_queue));
for (i = 0; i < workers_num; ++i) {
g_assert (!workers_data [i].stealable_stack_fill);
g_assert (sgen_gray_object_queue_is_empty (&workers_data [i].private_gray_queue));
}
}
