diff --git a/mesecons_luacontroller/init.lua b/mesecons_luacontroller/init.lua
index 1c411dd..a29b6da 100644
--- a/mesecons_luacontroller/init.lua
+++ b/mesecons_luacontroller/init.lua
@@ -590,8 +590,12 @@ local function load_memory(meta)
 end
 
 
-local function save_memory(pos, meta, mem)
-	local memstring = minetest.serialize(remove_functions(mem))
+local function serialize_memory(mem)
+	return minetest.serialize(remove_functions(mem))
+end
+
+
+local function save_serialized_memory(pos, meta, memstring)
 	local memsize_max = mesecon.setting("luacontroller_memsize", 100000)
 
 	if (#memstring <= memsize_max) then
@@ -629,6 +633,8 @@ local function run_inner(pos, code, event)
 	-- Create the sandbox and execute code
 	local f, msg = create_sandbox(code, env)
 	if not f then return false, msg end
+	local mem_use_limit = collectgarbage("count") + mesecon.setting("luacontroller_volatile_mem_limit", 2000)
+	local oom_msg = "not enough memory" -- Used to detect OOM errors, kind of a hack.
 	-- Start string true sandboxing
 	local onetruestring = getmetatable("")
 	-- If a string sandbox is already up yet inconsistent, something is very wrong
@@ -637,16 +643,43 @@ local function run_inner(pos, code, event)
 	local success, msg = pcall(f)
 	onetruestring.__index = string
 	-- End string true sandboxing
-	if not success then return false, msg end
+	if collectgarbage("count") > mem_use_limit then
+		-- Volatile memory limit exceeded.
+		success = false
+		msg = oom_msg
+	end
+	-- Serialize the persistent memory.
+	local memstring
+	if success then
+		success, memstring = pcall(serialize_memory, env.mem)
+		if not success then
+			msg = memstring
+			-- Rethrow non-OOM errors.
+			if msg ~= oom_msg then error(msg, 0) end
+		end
+	end
+	if not success then
+		-- Handle OOM errors by collecting garbage.
+		if msg == oom_msg then
+			env, itbl, mem = nil -- Let the memory be collected.
+			collectgarbage()
+			print("Error: Luacontroller at " .. minetest.pos_to_string(pos)
+					.. " exhausted its available volatile memory. Controller overheats.")
+			burn_controller(pos)
+		end
+		return false, msg
+	end
 	if type(env.port) ~= "table" then
 		return false, "Ports set are invalid."
 	end
+	local success, memstring = pcall(serialize_memory, env.mem)
+	if not success then return false, memstring end -- memstring is the error message here.
 
 	-- Actually set the ports
 	set_port_states(pos, env.port)
 
 	-- Save memory. This may burn the luacontroller if a memory overflow occurs.
-	save_memory(pos, meta, env.mem)
+	save_serialized_memory(pos, meta, memstring)
 
 	-- Execute deferred tasks
 	for _, v in ipairs(itbl) do
diff --git a/settingtypes.txt b/settingtypes.txt
index 5627440..7e247d1 100644
--- a/settingtypes.txt
+++ b/settingtypes.txt
@@ -24,6 +24,11 @@ mesecon.luacontroller_digiline_maxlen (Digiline message size limit) int 50000 10
 mesecon.luacontroller_maxevents (Controller execution time limit) int 10000 1000 100000
 mesecon.luacontroller_memsize (Controller memory limit) int 100000 10000 1000000
 
+# The amount of server memory a controller is allowed, measured in kilobytes.
+# This actually measures the memory usage after the script is done, not during its runtime.
+# Thus, controllers can lag the server even with a low limit.
+mesecon.luacontroller_volatile_mem_limit (Controller volatile memory limit) int 2000 10 10000000
+
 # Use node timer for interrupts (runs in active blocks only).
 # IID is ignored and at most one interrupt may be queued if this setting is enabled.
 mesecon.luacontroller_lightweight_interrupts (Lightweight interrupts) bool false