Merge pull request #2508 from cuberite/LogLuaMemoryStats

Added LuaState tracker and memory stats logging.

src/Bindings/LuaState.cpp

@@ -42,6 +42,76 @@ const cLuaState::cRet cLuaState::Return = {};
 
 
 
+////////////////////////////////////////////////////////////////////////////////
+// cLuaStateTracker:
+
+void cLuaStateTracker::Add(cLuaState & a_LuaState)
+{
+	auto & Instance = Get();
+	cCSLock Lock(Instance.m_CSLuaStates);
+	Instance.m_LuaStates.push_back(&a_LuaState);
+}
+
+
+
+
+void cLuaStateTracker::Del(cLuaState & a_LuaState)
+{
+	auto & Instance = Get();
+	cCSLock Lock(Instance.m_CSLuaStates);
+	Instance.m_LuaStates.erase(
+		std::remove_if(
+			Instance.m_LuaStates.begin(), Instance.m_LuaStates.end(),
+			[&a_LuaState](cLuaStatePtr a_StoredLuaState)
+			{
+				return (&a_LuaState == a_StoredLuaState);
+			}
+		),
+		Instance.m_LuaStates.end()
+	);
+}
+
+
+
+
+
+AString cLuaStateTracker::GetStats(void)
+{
+	auto & Instance = Get();
+	cCSLock Lock(Instance.m_CSLuaStates);
+	AString res;
+	int Total = 0;
+	for (auto state: Instance.m_LuaStates)
+	{
+		int Mem = 0;
+		if (!state->Call("collectgarbage", "count", cLuaState::Return, Mem))
+		{
+			res.append(Printf("Cannot query memory for state \"%s\"\n", state->GetSubsystemName().c_str()));
+		}
+		else
+		{
+			res.append(Printf("State \"%s\" is using %d KiB of memory\n", state->GetSubsystemName().c_str(), Mem));
+			Total += Mem;
+		}
+	}
+	res.append(Printf("Total memory used by Lua: %d KiB\n", Total));
+	return res;
+}
+
+
+
+
+
+cLuaStateTracker & cLuaStateTracker::Get(void)
+{
+	static cLuaStateTracker Inst;  // The singleton
+	return Inst;
+}
+
+
+
+
+
 ////////////////////////////////////////////////////////////////////////////////
 // cLuaState:
 
@@ -98,6 +168,7 @@ void cLuaState::Create(void)
 	m_LuaState = lua_open();
 	luaL_openlibs(m_LuaState);
 	m_IsOwned = true;
+	cLuaStateTracker::Add(*this);
 }
 
 
@@ -133,6 +204,7 @@ void cLuaState::Close(void)
 		Detach();
 		return;
 	}
+	cLuaStateTracker::Del(*this);
 	lua_close(m_LuaState);
 	m_LuaState = nullptr;
 	m_IsOwned = false;

src/Bindings/LuaState.h

@@ -210,6 +210,9 @@ public:
 	
 	/** Returns true if the m_LuaState is valid */
 	bool IsValid(void) const { return (m_LuaState != nullptr); }
+
+	/** Returns the name of the subsystem, as specified when the instance was created. */
+	AString GetSubsystemName(void) const { return m_SubsystemName; }
 	
 	/** Adds the specified path to package.<a_PathVariable> */
 	void AddPackagePath(const AString & a_PathVariable, const AString & a_Path);
@@ -521,3 +524,37 @@ protected:
 
 
 
+
+/** Keeps track of all create cLuaState instances.
+Can query each for the amount of currently used memory. */
+class cLuaStateTracker
+{
+public:
+	/** Adds the specified Lua state to the internal list of LuaStates. */
+	static void Add(cLuaState & a_LuaState);
+
+	/** Deletes the specified Lua state from the internal list of LuaStates. */
+	static void Del(cLuaState & a_LuaState);
+
+	/** Returns the statistics for all the registered LuaStates. */
+	static AString GetStats(void);
+
+protected:
+	typedef cLuaState * cLuaStatePtr;
+	typedef std::vector<cLuaStatePtr> cLuaStatePtrs;
+
+	/** The internal list of LuaStates.
+	Protected against multithreaded access by m_CSLuaStates. */
+	cLuaStatePtrs m_LuaStates;
+
+	/** Protects m_LuaStates against multithreaded access. */
+	cCriticalSection m_CSLuaStates;
+
+
+	/** Returns the single instance of this class. */
+	static cLuaStateTracker & Get(void);
+};
+
+
+
+

src/Server.cpp

@@ -145,6 +145,8 @@ cServer::cServer(void) :
 	m_ShouldLoadOfflinePlayerData(false),
 	m_ShouldLoadNamedPlayerData(true)
 {
+	// Initialize the LuaStateTracker singleton before the app goes multithreaded:
+	cLuaStateTracker::GetStats();
 }
 
 
@@ -522,6 +524,13 @@ void cServer::ExecuteConsoleCommand(const AString & a_Cmd, cCommandOutputCallbac
 		a_Output.Finished();
 		return;
 	}
+
+	else if (split[0].compare("luastats") == 0)
+	{
+		a_Output.Out(cLuaStateTracker::GetStats());
+		a_Output.Finished();
+		return;
+	}
 	#if defined(_MSC_VER) && defined(_DEBUG) && defined(ENABLE_LEAK_FINDER)
 	else if (split[0].compare("dumpmem") == 0)
 	{