diff --git a/libs/ardour/ardour/luaproc.h b/libs/ardour/ardour/luaproc.h
index 38d4961480..06478503f5 100644
--- a/libs/ardour/ardour/luaproc.h
+++ b/libs/ardour/ardour/luaproc.h
@@ -30,7 +30,6 @@
 #include <vector>
 #include <string>
 
-#define USE_TLSF
 #ifdef USE_TLSF
 #  include "pbd/tlsf.h"
 #else
diff --git a/libs/ardour/ardour/session.h b/libs/ardour/ardour/session.h
index fa61c27f32..5c510473b1 100644
--- a/libs/ardour/ardour/session.h
+++ b/libs/ardour/ardour/session.h
@@ -60,11 +60,15 @@
 #include "pbd/event_loop.h"
 #include "pbd/file_archive.h"
 #include "pbd/rcu.h"
-#include "pbd/reallocpool.h"
 #include "pbd/statefuldestructible.h"
 #include "pbd/signals.h"
 #include "pbd/undo.h"
 
+#ifdef USE_TLSF
+#  include "pbd/tlsf.h"
+#else
+#  include "pbd/reallocpool.h"
+#endif
 #include "lua/luastate.h"
 
 #include "temporal/range.h"
@@ -1652,7 +1656,11 @@ private:
 	bool              pending_abort;
 	bool              pending_auto_loop;
 
+#ifdef USE_TLSF
+	PBD::TLSF _mempool;
+#else
 	PBD::ReallocPool _mempool;
+#endif
 	LuaState lua;
 	mutable Glib::Threads::Mutex lua_lock;
 	luabridge::LuaRef * _lua_run;
diff --git a/libs/ardour/session.cc b/libs/ardour/session.cc
index 8dab2704e3..4839b1067b 100644
--- a/libs/ardour/session.cc
+++ b/libs/ardour/session.cc
@@ -258,8 +258,14 @@ Session::Session (AudioEngine &eng,
 	, _last_roll_or_reversal_location (0)
 	, _last_record_location (0)
 	, pending_auto_loop (false)
-	, _mempool ("Session", 3145728)
+	, _mempool ("Session", 4194304)
+#ifdef USE_TLSF
+	, lua (lua_newstate (&PBD::TLSF::lalloc, &_mempool))
+#elif defined USE_MALLOC
+	, lua (lua_newstate (true, true))
+#else
 	, lua (lua_newstate (&PBD::ReallocPool::lalloc, &_mempool))
+#endif
 	, _lua_run (0)
 	, _lua_add (0)
 	, _lua_del (0)
diff --git a/libs/ardour/wscript b/libs/ardour/wscript
index 777a0325f1..4743a4eb75 100644
--- a/libs/ardour/wscript
+++ b/libs/ardour/wscript
@@ -321,6 +321,8 @@ def configure(conf):
                       atleast_version='0.24.2', mandatory=True)
     conf.define ('LV2_SUPPORT', 1)
 
+    conf.define ('USE_TLSF', 1)
+
     # non-standard LV2 extention -- TODO: add option to disable??
     if conf.is_defined ('HAVE_LV2_1_10_0'):
         conf.define ('LV2_EXTENDED', 1)