=== modified file 'src/alloc.c'
--- src/alloc.c	2011-12-12 05:32:49 +0000
+++ src/alloc.c	2011-12-19 06:06:04 +0000
@@ -75,6 +75,10 @@
 
 #define MMAP_MAX_AREAS 100000000
 
+/* Value of mallinfo ().fordblks as seen at the end of last GC.  */
+
+static int bytes_free;
+
 #else /* not DOUG_LEA_MALLOC */
 
 /* The following come from gmalloc.c.  */
@@ -5271,6 +5275,10 @@
   total[7] = Fcons (make_number (total_strings),
 		    make_number (total_free_strings));
 
+#ifdef DOUG_LEA_MALLOC
+  bytes_free = mallinfo ().fordblks;
+#endif
+
 #if GC_MARK_STACK == GC_USE_GCPROS_CHECK_ZOMBIES
   {
     /* Compute average percentage of zombies.  */
@@ -6221,6 +6229,33 @@
   return end;
 }
 
+DEFUN ("memory-free", Fmemory_free, Smemory_free, 0, 0, 0,
+       doc: /* Return a list of two counters that measure how much free
+memory is hold by the Emacs process. Both counters are
+in KBytes. First counter shows how much memory holds in
+a free lists maintained by the Emacs itself. Second counter
+shows how much free memory is in the heap. If the second
+counter is zero, heap statistics is not available.  */)
+     (void)
+{
+  Lisp_Object data[2];
+  
+  data[0] = make_number
+    (min (MOST_POSITIVE_FIXNUM,
+	  (total_free_conses * sizeof (struct Lisp_Cons) +
+	   total_free_markers * sizeof (union Lisp_Misc) +
+	   total_free_symbols * sizeof (struct Lisp_Symbol) +
+	   total_free_floats * sizeof (struct Lisp_Float) +
+	   total_free_intervals * sizeof (struct interval) +
+	   total_free_strings * sizeof (struct Lisp_String)) / 1024));
+#ifdef DOUG_LEA_MALLOC
+  data[1] = make_number (min (MOST_POSITIVE_FIXNUM, bytes_free / 1024));
+#else
+  data[1] = make_number (0);
+#endif
+  return Flist (2, data);
+}
+
 DEFUN ("memory-use-counts", Fmemory_use_counts, Smemory_use_counts, 0, 0, 0,
        doc: /* Return a list of counters that measure how much consing there has been.
 Each of these counters increments for a certain kind of object.
@@ -6474,6 +6509,7 @@
   defsubr (&Spurecopy);
   defsubr (&Sgarbage_collect);
   defsubr (&Smemory_limit);
+  defsubr (&Smemory_free);
   defsubr (&Smemory_use_counts);
 
 #if GC_MARK_STACK == GC_USE_GCPROS_CHECK_ZOMBIES