Peter M. Groen / openbr

Commit 5d5bca6a394916c65d1fa386a5b0b44d4d20f76b

Authored by Charles Otto
1 parent 8057fb57

Rearrange the release/reserve threads in stream::projectUpdate 

In stream projectUpdate, queue the intial worker thread before calling
releaseThread, and waiting. Also, call reserveThread before the last worker
thread ends.

The goal here is to avoid cases where the threadCount is increased, before the
extra thread is used up by the current stream, as part of a scheme to avoid
deadlocks related to using stream within an active distribute transform.
Inline Side-by-side
Showing 1 changed file with 13 additions and 5 deletions
openbr/plugins/stream.cpp
  View file @5d5bca6
... ... @@ -226,6 +226,12 @@ public:
226 226 last_received = inputFrame->sequenceNumber;
227 227  
228 228 if (inputFrame->sequenceNumber == final_frame) {
  229 + // This is the reserveThread that matches the releaseThread in
  230 + // Stream::projectUpdate, we do it here to prevent a gap where the
  231 + // thread count is still increased, but a stream worker thread is not
  232 + // running, which might allow something to start that shouldn't
  233 + // start yet.
  234 + QThreadPool::globalInstance()->reserveThread();
229 235 // We just received the last frame, better pulse
230 236 lastReturned.wakeAll();
231 237 rval = true;
... ... @@ -630,7 +636,7 @@ public:
630 636 next->start_idx = this->stage_id;
631 637 next->startItem = newItem;
632 638  
633   - QThreadPool::globalInstance()->start(next, stages->size() - this->stage_id);
  639 + QThreadPool::globalInstance()->start(next, stages->size() - stage_id);
634 640 }
635 641  
636 642 return input;
... ... @@ -700,7 +706,7 @@ public:
700 706 next->start_idx = this->stage_id;
701 707 next->startItem = NULL;
702 708  
703   - QThreadPool::globalInstance()->start(next, stages->size() - this->stage_id);
  709 + QThreadPool::globalInstance()->start(next, stages->size() - stage_id);
704 710  
705 711 return input;
706 712 }
... ... @@ -791,7 +797,7 @@ public:
791 797 next->start_idx = this->stage_id;
792 798 next->startItem = newItem;
793 799  
794   - QThreadPool::globalInstance()->start(next, stages->size() - this->stage_id);
  800 + QThreadPool::globalInstance()->start(next, stages->size() - stage_id);
795 801 }
796 802  
797 803 return input;
... ... @@ -831,7 +837,6 @@ public:
831 837 bool res = readStage->dataSource.open(dst);
832 838 if (!res) return;
833 839  
834   - QThreadPool::globalInstance()->releaseThread();
835 840 readStage->currentStatus = SingleThreadStage::STARTING;
836 841  
837 842 BasicLoop loop;
... ... @@ -840,11 +845,14 @@ public:
840 845 loop.startItem = NULL;
841 846 loop.setAutoDelete(false);
842 847  
  848 + // Create a thread, then allow it to start by releasing. We queue the thread
  849 + // first so that any lower priority threads that are already queued don't start
  850 + // instead of the new one.
843 851 QThreadPool::globalInstance()->start(&loop, processingStages.size() - processingStages[0]->stage_id);
  852 + QThreadPool::globalInstance()->releaseThread();
844 853  
845 854 // Wait for the end.
846 855 readStage->dataSource.waitLast();
847   - QThreadPool::globalInstance()->reserveThread();
848 856  
849 857 TemplateList final_output;
850 858  
... ...