More comments

theano/gof/cmodule.py

@@ -390,6 +390,9 @@ class ModuleCache(object):
             rval = self.module_from_name[name]
         else:
             # we have never seen this key before
+            # Acquire lock before creating things in the compile cache,
+            # to avoid that other processes remove the compile dire while it
+            # is still empty
             compilelock.get_lock()
             location = dlimport_workdir(self.dirname)
             #debug("LOCATION*", location)
@@ -512,8 +515,11 @@ class ModuleCache(object):
                 except IOError:
                     has_key = False
                 if not has_key:
-                    #TODO: only if older than 1 week?
-                    # it might still be used by another process
+                    #TODO: Remove this, or at least wait one week
+                    # This cache dir is either in use by another process
+                    # (in that case, it will be removed by the code above),
+                    # or a remnant of a crashed process, in that case, it will
+                    # be removed by clear_old at some point.
                     info("clear_unversioned removing cache dir", filename)
                     _rmtree(os.path.join(self.dirname, filename))