do not expose memory_maps if kernel does not support it (was raising …

…NotImplemented exception

CREDITS

@@ -375,3 +375,6 @@ I: 751
 N: mpderbec
 W: https://github.com/mpderbec
 I: 660
+
+N: Mozilla Foundation
+D: sample code for process USS memory.

psutil/_pslinux.py

@@ -970,6 +970,8 @@ def memory_info(self):
                 [int(x) * PAGESIZE for x in f.readline().split()[:7]]
             return pmem(rss, vms, shared, text, lib, data, dirty)
 
+    # /proc/pid/smaps does not exist on kernels < 2.6.14 or if
+    # CONFIG_MMU kernel configuration option is not enabled.
     if HAS_SMAPS:
 
         @wrap_exceptions
@@ -1049,13 +1051,6 @@ def get_blocks():
                         ))
             return ls
 
-    else:
-        def memory_maps(self):
-            msg = "couldn't find /proc/%s/smaps; kernel < 2.6.14 or "  \
-                  "CONFIG_MMU kernel configuration option is not enabled" \
-                  % self.pid
-            raise NotImplementedError(msg)
-
     @wrap_exceptions
     def cwd(self):
         return readlink("%s/%s/cwd" % (self._procfs_path, self.pid))

psutil/_psutil_windows.c

@@ -801,6 +801,9 @@ psutil_proc_memory_info_2(PyObject *self, PyObject *args) {
 
 /**
  * Returns the USS of the process.
+ * Reference:
+ * https://dxr.mozilla.org/mozilla-central/source/xpcom/base/
+ *     nsMemoryReporterManager.cpp
  */
 static PyObject *
 psutil_proc_memory_uss(PyObject *self, PyObject *args)