STATIC_INLINE void
newReturningTask (Capability *cap, Task *task)
{
ASSERT_LOCK_HELD(&cap->lock);
ASSERT(task->next == NULL);
if (cap->returning_tasks_hd) {
ASSERT(cap->returning_tasks_tl->next == NULL);
cap->returning_tasks_tl->next = task;
} else {
cap->returning_tasks_hd = task;
}
cap->returning_tasks_tl = task;
}
STATIC_INLINE Task *
popReturningTask (Capability *cap)
{
ASSERT_LOCK_HELD(&cap->lock);
Task *task;
task = cap->returning_tasks_hd;
ASSERT(task);
cap->returning_tasks_hd = task->next;
if (!cap->returning_tasks_hd) {
cap->returning_tasks_tl = NULL;
}
task->next = NULL;
return task;
}
void
startWorkerTask (Capability *cap)
{
int r;
OSThreadId tid;
Task *task;
// A worker always gets a fresh Task structure.
task = newTask(rtsTrue);
// The lock here is to synchronise with taskStart(), to make sure
// that we have finished setting up the Task structure before the
// worker thread reads it.
ACQUIRE_LOCK(&task->lock);
// We don't emit a task creation event here, but in workerStart,
// where the kernel thread id is known.
task->cap = cap;
// Give the capability directly to the worker; we can't let anyone
// else get in, because the new worker Task has nowhere to go to
// sleep so that it could be woken up again.
ASSERT_LOCK_HELD(&cap->lock);
cap->running_task = task;
r = createOSThread(&tid, (OSThreadProc*)workerStart, task);
if (r != 0) {
sysErrorBelch("failed to create OS thread");
stg_exit(EXIT_FAILURE);
}
debugTrace(DEBUG_sched, "new worker task (taskCount: %d)", taskCount);
task->id = tid;
// ok, finished with the Task struct.
RELEASE_LOCK(&task->lock);
}