[pypy-commit] pypy incremental-gc: Add a comment

[arigo]

Author: Armin Rigo <arigo at tunes.org>
Branch: incremental-gc
Changeset: r67084:49d8f5ae9b89
Date: 2013-09-24 10:35 +0200
http://bitbucket.org/pypy/pypy/changeset/49d8f5ae9b89/

Log:	Add a comment

diff --git a/rpython/memory/gc/incminimark.py b/rpython/memory/gc/incminimark.py
--- a/rpython/memory/gc/incminimark.py
+++ b/rpython/memory/gc/incminimark.py
@@ -2023,6 +2023,8 @@
 
     def _collect_ref_rec(self, root, ignored):
         obj = root.address[0]
+        # XXX minimark.py doesn't read anything from 'obj' here.
+        # Can this lead to seriously more cache pressure?
         if self.header(obj).tid & (GCFLAG_VISITED|GCFLAG_GRAY) != 0:
             return
         self.header(obj).tid |= GCFLAG_GRAY