Moved GC to background thread and added endpoint to trigger/status GC.

2 files changed, 48 insertions, 2 deletions

diff --git a/zenstore/gc.cpp b/zenstore/gc.cpp
index 278f09b0b..52bb33955 100644
--- a/zenstore/gc.cpp
+++ b/zenstore/gc.cpp
@@ -2,9 +2,11 @@
 
 #include <zenstore/gc.h>
 
+#include <zencore/logging.h>
+#include <zencore/string.h>
+#include <zencore/timer.h>
 #include <zenstore/CAS.h>
 #include <zenstore/cidstore.h>
-#include <zencore/logging.h>
 
 namespace zen {
 
@@ -202,4 +204,28 @@ CasGc::OnDroppedCidReferences(std::span<IoHash> Hashes)
 	ZEN_UNUSED(Hashes);
 }
 
+bool
+Gc::Trigger()
+{
+	uint32_t Expected = uint32_t(GcStatus::kIdle);
+	if (!m_Status.compare_exchange_strong(Expected, static_cast<uint32_t>(GcStatus::kRunning)))
+	{
+		return false;
+	}
+
+	ZEN_ASSERT(GcStatus::kRunning == Status());
+
+	m_GcThread = std::jthread([this]() {
+		Stopwatch Timer;
+		ZEN_INFO("garbage collection STARTING");
+
+		m_CasGc.CollectGarbage();
+		m_Status = static_cast<uint32_t>(GcStatus::kIdle);
+
+		ZEN_INFO("garbage collection DONE after {}", NiceTimeSpanMs(Timer.GetElapsedTimeMs()));
+	});
+
+	return true;
+}
+
 }  // namespace zen
diff --git a/zenstore/include/zenstore/gc.h b/zenstore/include/zenstore/gc.h
index 560642803..8efe933a0 100644
--- a/zenstore/include/zenstore/gc.h
+++ b/zenstore/include/zenstore/gc.h
@@ -5,8 +5,9 @@
 #include <zencore/iohash.h>
 #include <zencore/thread.h>
 
-#include <span>
+#include <atomic>
 #include <functional>
+#include <span>
 
 #define ZEN_USE_REF_TRACKING 0	// This is not currently functional
 
@@ -107,4 +108,23 @@ private:
 	CidStore*					m_CidStore;
 };
 
+enum class GcStatus : uint32_t
+{
+	kIdle,
+	kRunning
+};
+
+class Gc
+{
+public:
+	bool	 Trigger();
+	CasGc&	 Cas() { return m_CasGc; }
+	GcStatus Status() const { return static_cast<GcStatus>(m_Status.load()); }
+
+private:
+	CasGc				 m_CasGc;
+	std::jthread		 m_GcThread;
+	std::atomic_uint32_t m_Status;
+};
+
 }  // namespace zen