Force garbage collection.

mapgen.lua

@@ -468,14 +468,6 @@ local function generate(p_minp, p_maxp, seed)
 		vm:update_liquids()
 		vm:write_to_map()
 	end
-
-	-- Deal with memory issues. This, of course, is supposed to be automatic.
-	minetest.after(0, function()
-		if math.floor(collectgarbage("count")/1024) > 400 then
-			print("Fun Caves: Manually collecting garbage...")
-			collectgarbage("collect")
-		end
-	end)
 end
 
 
@@ -493,6 +485,16 @@ end
 
 
 local function pgenerate(...)
+	if math.floor(collectgarbage("count")/1024) > 400 then
+		print("Fun Caves: Manually collecting garbage...")
+		collectgarbage("collect")
+
+		-- Slow down to allow time to free memory.
+		local clock = os.clock
+		local t0 = clock()
+		while clock() - t0 <= 2 do end
+	end
+
 	local status, err = pcall(generate, ...)
 	if not status then
 		print(dump(err))