diff --git a/django/core/urlresolvers.py b/django/core/urlresolvers.py
index 1a56f11dda..34b40db6c6 100644
--- a/django/core/urlresolvers.py
+++ b/django/core/urlresolvers.py
@@ -38,29 +38,27 @@ def get_callable(lookup_view, can_fail=False):
     If can_fail is True, lookup_view might be a URL pattern label, so errors
     during the import fail and the string is returned.
     """
-    try:
-        # Bail out early if lookup_view is not ASCII. This can't be a function.
-        lookup_view = lookup_view.encode('ascii')
-
-        if not callable(lookup_view):
+    if not callable(lookup_view):
+        try:
+            # Bail early for non-ASCII strings (they can't be functions).
+            lookup_view = lookup_view.encode('ascii')
             mod_name, func_name = get_mod_func(lookup_view)
-            try:
-                if func_name != '':
-                    lookup_view = getattr(__import__(mod_name, {}, {}, ['']), func_name)
-            except (ImportError, AttributeError):
-                if not can_fail:
-                    raise
-    except UnicodeEncodeError:
-        pass
+            if func_name != '':
+                lookup_view = getattr(__import__(mod_name, {}, {}, ['']), func_name)
+        except (ImportError, AttributeError):
+            if not can_fail:
+                raise
+        except UnicodeEncodeError:
+            pass
     return lookup_view
-get_callable = memoize(get_callable, _callable_cache)
+get_callable = memoize(get_callable, _callable_cache, 1)
 
 def get_resolver(urlconf):
     if urlconf is None:
         from django.conf import settings
         urlconf = settings.ROOT_URLCONF
     return RegexURLResolver(r'^/', urlconf)
-get_resolver = memoize(get_resolver, _resolver_cache)
+get_resolver = memoize(get_resolver, _resolver_cache, 1)
 
 def get_mod_func(callback):
     # Converts 'django.views.news.stories.story_detail' to
diff --git a/django/utils/functional.py b/django/utils/functional.py
index 656f3406c4..734704f6f3 100644
--- a/django/utils/functional.py
+++ b/django/utils/functional.py
@@ -3,18 +3,20 @@ def curry(_curried_func, *args, **kwargs):
         return _curried_func(*(args+moreargs), **dict(kwargs, **morekwargs))
     return _curried
 
-def memoize(func, cache):
+def memoize(func, cache, num_args):
     """
     Wrap a function so that results for any argument tuple are stored in
     'cache'. Note that the args to the function must be usable as dictionary
     keys.
+
+    Only the first num_args are considered when creating the key.
     """
     def wrapper(*args):
-        if args in cache:
-            return cache[args]
-
+        mem_args = args[:num_args]
+        if mem_args in cache:
+            return cache[mem_args]
         result = func(*args)
-        cache[args] = result
+        cache[mem_args] = result
         return result
     return wrapper