different definition for space_subsize.

Former-commit-id: 69565dbcc80776cc74c9820ff929b8199708a96a

src/space.h

@@ -25,11 +25,11 @@
 #define space_cellallocchunk            1000
 #define space_splitratio                0.875f
 #define space_splitsize_default         400
-#define space_maxsize_default           25000000
-#define space_subsize_default           5000
+#define space_maxsize_default           8000000
+#define space_subsize_default           8000000
 #define space_stretch                   1.10f
 #define space_maxreldx                  0.25f
-#define space_qstack                    1024
+#define space_qstack                    2048
 
 
 /* Convert cell location to ID. */