05-track-live-dataset-size.patch

diff --git a/gc.c b/gc.c
index 7f65b98..8498fe4 100644
--- a/gc.c
+++ b/gc.c
@@ -281,7 +281,6 @@ getrusage_time(void)
 #define GC_PROF_DEC_LIVE_NUM
 #endif
 
-
 #if defined(_MSC_VER) || defined(__BORLANDC__) || defined(__CYGWIN__)
 #pragma pack(push, 1) /* magic for reducing sizeof(RVALUE): 24 -> 20 */
 #endif
@@ -1562,6 +1561,24 @@ rb_gc_time()
 #endif
 }
 
+/*
+ *  call-seq:
+ *     GC.heap_slots_live_after_last_gc    => Integer
+ *
+ *  Returns the number of heap slots which were live after the last garbage collection.
+ *
+ *     GC.heap_slots_live_after_last_gc    #=> 231223
+ *
+ */
+VALUE
+rb_gc_heap_slots_live_after_last_gc()
+{
+    rb_objspace_t *objspace = &rb_objspace;
+    return ULONG2NUM(live_after_last_mark_phase);
+}
+
+
+
 VALUE rb_mGC;
 
 void
@@ -4533,6 +4550,7 @@ Init_GC(void)
     rb_define_singleton_method(rb_mGC, "allocated_size", rb_gc_allocated_size, 0);
     rb_define_singleton_method(rb_mGC, "num_allocations", rb_gc_num_allocations, 0);
     rb_define_singleton_method(rb_mGC, "heap_slots", rb_gc_heap_slots, 0);
+    rb_define_singleton_method(rb_mGC, "heap_slots_live_after_last_gc", rb_gc_heap_slots_live_after_last_gc, 0);
     rb_define_const(rb_mGC, "HEAP_SLOT_SIZE", INT2FIX(sizeof(RVALUE)));
 
     rb_define_singleton_method(rb_mGC, "log", rb_gc_log, 1);