diff src/share/vm/memory/cardTableRS.cpp @ 3293:1f4413413144

7039089: G1: changeset for 7037276 broke heap verification, and related cleanups Summary: In G1 heap verification, we no longer scan perm to G1-collected heap refs as part of process_strong_roots() but rather in a separate explicit oop iteration over the perm gen. This preserves the original perm card-marks. Added a new assertion in younger_refs_iterate() to catch a simple subcase where the user may have forgotten a prior save_marks() call, as happened in the case of G1's attempt to iterate perm to G1 refs when verifying the heap before exit. The assert was deliberately weakened for ParNew+CMS and will be fixed for that combination in a future CR. Also made some (non-G1) cleanups related to code and comments obsoleted by the migration of Symbols to the native heap. Reviewed-by: iveresov, jmasa, tonyp
author ysr
date Tue, 26 Apr 2011 21:17:24 -0700
parents c48ad6ab8bdf
children fc2b798ab316
line wrap: on
line diff
--- a/src/share/vm/memory/cardTableRS.cpp	Tue Apr 26 11:46:34 2011 -0700
+++ b/src/share/vm/memory/cardTableRS.cpp	Tue Apr 26 21:17:24 2011 -0700
@@ -250,7 +250,34 @@
                                                    cl->gen_boundary());
   ClearNoncleanCardWrapper clear_cl(dcto_cl, this);
 
-  _ct_bs->non_clean_card_iterate_possibly_parallel(sp, sp->used_region_at_save_marks(),
+  const MemRegion urasm = sp->used_region_at_save_marks();
+#ifdef ASSERT
+  // Convert the assertion check to a warning if we are running
+  // CMS+ParNew until related bug is fixed.
+  MemRegion ur    = sp->used_region();
+  assert(ur.contains(urasm) || (UseConcMarkSweepGC && UseParNewGC),
+         err_msg("Did you forget to call save_marks()? "
+                 "[" PTR_FORMAT ", " PTR_FORMAT ") is not contained in "
+                 "[" PTR_FORMAT ", " PTR_FORMAT ")",
+                 urasm.start(), urasm.end(), ur.start(), ur.end()));
+  // In the case of CMS+ParNew, issue a warning
+  if (!ur.contains(urasm)) {
+    assert(UseConcMarkSweepGC && UseParNewGC, "Tautology: see assert above");
+    warning("CMS+ParNew: Did you forget to call save_marks()? "
+            "[" PTR_FORMAT ", " PTR_FORMAT ") is not contained in "
+            "[" PTR_FORMAT ", " PTR_FORMAT ")",
+             urasm.start(), urasm.end(), ur.start(), ur.end());
+    MemRegion ur2 = sp->used_region();
+    MemRegion urasm2 = sp->used_region_at_save_marks();
+    if (!ur.equals(ur2)) {
+      warning("CMS+ParNew: Flickering used_region()!!");
+    }
+    if (!urasm.equals(urasm2)) {
+      warning("CMS+ParNew: Flickering used_region_at_save_marks()!!");
+    }
+  }
+#endif
+  _ct_bs->non_clean_card_iterate_possibly_parallel(sp, urasm,
                                                    dcto_cl, &clear_cl);
 }