Merge pull request #66 from EpicGames/de/gracefully-exit-gc

Make sure we wait for gc thread to complete before exiting

1 files changed, 15 insertions, 9 deletions

diff --git a/zenstore/gc.cpp b/zenstore/gc.cpp
index 7be93b4af..0f7a11789 100644
--- a/zenstore/gc.cpp
+++ b/zenstore/gc.cpp
@@ -419,10 +419,13 @@ GcScheduler::Trigger(const GcScheduler::TriggerParams& Params)
 		std::unique_lock Lock(m_GcMutex);
 		if (static_cast<uint32_t>(GcSchedulerStatus::kIdle) == m_Status)
 		{
-			m_TriggerParams = Params;
-			m_Status		= static_cast<uint32_t>(GcSchedulerStatus::kRunning);
-			m_GcSignal.notify_one();
-			return true;
+			m_TriggerParams	   = Params;
+			uint32_t IdleState = static_cast<uint32_t>(GcSchedulerStatus::kIdle);
+			if (m_Status.compare_exchange_strong(IdleState, static_cast<uint32_t>(GcSchedulerStatus::kRunning)))
+			{
+				m_GcSignal.notify_one();
+				return true;
+			}
 		}
 	}
 
@@ -486,12 +489,14 @@ GcScheduler::SchedulerThread()
 				continue;
 			}
 
-			WaitTime = m_Config.MonitorInterval;
-			m_Status = static_cast<uint32_t>(GcSchedulerStatus::kRunning);
+			WaitTime		   = m_Config.MonitorInterval;
+			uint32_t IdleState = static_cast<uint32_t>(GcSchedulerStatus::kIdle);
+			if (!m_Status.compare_exchange_strong(IdleState, static_cast<uint32_t>(GcSchedulerStatus::kRunning)))
+			{
+				continue;
+			}
 		}
 
-		ZEN_ASSERT(Status() == GcSchedulerStatus::kRunning);
-
 		GcContext GcCtx;
 		GcCtx.SetDeletionMode(true);
 		GcCtx.CollectSmallObjects(m_Config.CollectSmallObjects);
@@ -531,7 +536,8 @@ GcScheduler::SchedulerThread()
 
 		ZEN_INFO("garbage collection DONE after {}", NiceTimeSpanMs(Timer.GetElapsedTimeMs()));
 
-		m_Status = static_cast<uint32_t>(GcSchedulerStatus::kIdle);
+		uint32_t RunningState = static_cast<uint32_t>(GcSchedulerStatus::kRunning);
+		m_Status.compare_exchange_strong(RunningState, static_cast<uint32_t>(GcSchedulerStatus::kIdle));
 	}
 }