mirror of
https://github.com/godotengine/godot
synced 2024-09-05 17:59:56 +00:00
ResourceLoader: Avoid deadlock when awaiting a loader thread that failed early
This commit is contained in:
parent
3a11eb9818
commit
bdcceef0e2
|
@ -656,39 +656,50 @@ Ref<Resource> ResourceLoader::_load_complete_inner(LoadToken &p_load_token, Erro
|
|||
return Ref<Resource>();
|
||||
}
|
||||
|
||||
if (load_task.task_id != 0) {
|
||||
bool loader_is_wtp = load_task.task_id != 0;
|
||||
Error wtp_task_err = FAILED;
|
||||
if (loader_is_wtp) {
|
||||
// Loading thread is in the worker pool.
|
||||
thread_load_mutex.unlock();
|
||||
Error err = WorkerThreadPool::get_singleton()->wait_for_task_completion(load_task.task_id);
|
||||
if (err == ERR_BUSY) {
|
||||
// The WorkerThreadPool has reported that the current task wants to await on an older one.
|
||||
// That't not allowed for safety, to avoid deadlocks. Fortunately, though, in the context of
|
||||
// resource loading that means that the task to wait for can be restarted here to break the
|
||||
// cycle, with as much recursion into this process as needed.
|
||||
// When the stack is eventually unrolled, the original load will have been notified to go on.
|
||||
// CACHE_MODE_IGNORE is needed because, otherwise, the new request would just see there's
|
||||
// an ongoing load for that resource and wait for it again. This value forces a new load.
|
||||
Ref<ResourceLoader::LoadToken> token = _load_start(load_task.local_path, load_task.type_hint, LOAD_THREAD_DISTRIBUTE, ResourceFormatLoader::CACHE_MODE_IGNORE);
|
||||
Ref<Resource> resource = _load_complete(*token.ptr(), &err);
|
||||
if (r_error) {
|
||||
*r_error = err;
|
||||
wtp_task_err = WorkerThreadPool::get_singleton()->wait_for_task_completion(load_task.task_id);
|
||||
}
|
||||
|
||||
if (load_task.status == THREAD_LOAD_IN_PROGRESS) { // If early errored, awaiting would deadlock.
|
||||
if (loader_is_wtp) {
|
||||
if (wtp_task_err == ERR_BUSY) {
|
||||
// The WorkerThreadPool has reported that the current task wants to await on an older one.
|
||||
// That't not allowed for safety, to avoid deadlocks. Fortunately, though, in the context of
|
||||
// resource loading that means that the task to wait for can be restarted here to break the
|
||||
// cycle, with as much recursion into this process as needed.
|
||||
// When the stack is eventually unrolled, the original load will have been notified to go on.
|
||||
// CACHE_MODE_IGNORE is needed because, otherwise, the new request would just see there's
|
||||
// an ongoing load for that resource and wait for it again. This value forces a new load.
|
||||
Ref<ResourceLoader::LoadToken> token = _load_start(load_task.local_path, load_task.type_hint, LOAD_THREAD_DISTRIBUTE, ResourceFormatLoader::CACHE_MODE_IGNORE);
|
||||
Ref<Resource> resource = _load_complete(*token.ptr(), &wtp_task_err);
|
||||
if (r_error) {
|
||||
*r_error = wtp_task_err;
|
||||
}
|
||||
thread_load_mutex.lock();
|
||||
return resource;
|
||||
} else {
|
||||
DEV_ASSERT(wtp_task_err == OK);
|
||||
thread_load_mutex.lock();
|
||||
load_task.awaited = true;
|
||||
}
|
||||
thread_load_mutex.lock();
|
||||
return resource;
|
||||
} else {
|
||||
DEV_ASSERT(err == OK);
|
||||
thread_load_mutex.lock();
|
||||
load_task.awaited = true;
|
||||
// Loading thread is main or user thread.
|
||||
if (!load_task.cond_var) {
|
||||
load_task.cond_var = memnew(ConditionVariable);
|
||||
}
|
||||
do {
|
||||
load_task.cond_var->wait(p_thread_load_lock);
|
||||
DEV_ASSERT(thread_load_tasks.has(p_load_token.local_path) && p_load_token.get_reference_count());
|
||||
} while (load_task.cond_var);
|
||||
}
|
||||
} else {
|
||||
// Loading thread is main or user thread.
|
||||
if (!load_task.cond_var) {
|
||||
load_task.cond_var = memnew(ConditionVariable);
|
||||
if (loader_is_wtp) {
|
||||
thread_load_mutex.lock();
|
||||
}
|
||||
do {
|
||||
load_task.cond_var->wait(p_thread_load_lock);
|
||||
DEV_ASSERT(thread_load_tasks.has(p_load_token.local_path) && p_load_token.get_reference_count());
|
||||
} while (load_task.cond_var);
|
||||
}
|
||||
}
|
||||
|
||||
|
|
Loading…
Reference in a new issue