--- a/hotspot/src/share/vm/memory/generation.hpp	Thu Oct 21 17:29:24 2010 -0700
+++ b/hotspot/src/share/vm/memory/generation.hpp	Sat Oct 23 23:03:49 2010 -0700
@@ -173,15 +173,11 @@
   // The largest number of contiguous free bytes in this or any higher generation.
   virtual size_t max_contiguous_available() const;
 
-  // Returns true if promotions of the specified amount can
-  // be attempted safely (without a vm failure).
+  // Returns true if promotions of the specified amount are
+  // likely to succeed without a promotion failure.
   // Promotion of the full amount is not guaranteed but
-  // can be attempted.
-  //   younger_handles_promotion_failure
-  // is true if the younger generation handles a promotion
-  // failure.
-  virtual bool promotion_attempt_is_safe(size_t promotion_in_bytes,
-    bool younger_handles_promotion_failure) const;
+  // might be attempted in the worst case.
+  virtual bool promotion_attempt_is_safe(size_t max_promotion_in_bytes) const;
 
   // For a non-young generation, this interface can be used to inform a
   // generation that a promotion attempt into that generation failed.
@@ -358,6 +354,16 @@
     return (full || should_allocate(word_size, is_tlab));
   }
 
+  // Returns true if the collection is likely to be safely
+  // completed. Even if this method returns true, a collection
+  // may not be guaranteed to succeed, and the system should be
+  // able to safely unwind and recover from that failure, albeit
+  // at some additional cost.
+  virtual bool collection_attempt_is_safe() {
+    guarantee(false, "Are you sure you want to call this method?");
+    return true;
+  }
+
   // Perform a garbage collection.
   // If full is true attempt a full garbage collection of this generation.
   // Otherwise, attempting to (at least) free enough space to support an