--- a/mercurial/dirstate.py Mon Feb 11 01:17:50 2013 +0100
+++ b/mercurial/dirstate.py Mon Feb 11 01:21:24 2013 +0100
@@ -9,7 +9,7 @@
from node import nullid
from i18n import _
import scmutil, util, ignore, osutil, parsers, encoding
-import os, stat, errno
+import os, stat, errno, gc
propertycache = util.propertycache
filecache = scmutil.filecache
@@ -285,7 +285,23 @@
if not st:
return
- p = parsers.parse_dirstate(self._map, self._copymap, st)
+ # Python's garbage collector triggers a GC each time a certain number
+ # of container objects (the number being defined by
+ # gc.get_threshold()) are allocated. parse_dirstate creates a tuple
+ # for each file in the dirstate. The C version then immediately marks
+ # them as not to be tracked by the collector. However, this has no
+ # effect on when GCs are triggered, only on what objects the GC looks
+ # into. This means that O(number of files) GCs are unavoidable.
+ # Depending on when in the process's lifetime the dirstate is parsed,
+ # this can get very expensive. As a workaround, disable GC while
+ # parsing the dirstate.
+ gcenabled = gc.isenabled()
+ gc.disable()
+ try:
+ p = parsers.parse_dirstate(self._map, self._copymap, st)
+ finally:
+ if gcenabled:
+ gc.enable()
if not self._dirtypl:
self._pl = p