--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Thu Aug 23 10:21:12 2012 +0200
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.cpp	Tue Aug 28 15:20:08 2012 -0700
@@ -1945,6 +1945,9 @@
 
   clear_cset_start_regions();
 
+  // Initialize the G1EvacuationFailureALot counters and flags.
+  NOT_PRODUCT(reset_evacuation_should_fail();)
+
   guarantee(_task_queues != NULL, "task_queues allocation failure.");
 #ifdef SPARC
   // Issue a stern warning, but allow use for experimentation and debugging.
@@ -4564,7 +4567,15 @@
   GCAllocPurpose alloc_purpose = g1p->evacuation_destination(from_region, age,
                                                              word_sz);
   HeapWord* obj_ptr = _par_scan_state->allocate(alloc_purpose, word_sz);
-  oop       obj     = oop(obj_ptr);
+#ifndef PRODUCT
+  // Should this evacuation fail?
+  if (_g1->evacuation_should_fail()) {
+    if (obj_ptr != NULL) {
+      _par_scan_state->undo_allocation(alloc_purpose, obj_ptr, word_sz);
+      obj_ptr = NULL;
+    }
+  }
+#endif // !PRODUCT
 
   if (obj_ptr == NULL) {
     // This will either forward-to-self, or detect that someone else has
@@ -4573,6 +4584,8 @@
     return _g1->handle_evacuation_failure_par(cl, old);
   }
 
+  oop obj = oop(obj_ptr);
+
   // We're going to allocate linearly, so might as well prefetch ahead.
   Prefetch::write(obj_ptr, PrefetchCopyIntervalInBytes);
 
@@ -5578,6 +5591,9 @@
   _expand_heap_after_alloc_failure = true;
   set_evacuation_failed(false);
 
+  // Should G1EvacuationFailureALot be in effect for this GC?
+  NOT_PRODUCT(set_evacuation_failure_alot_for_current_gc();)
+
   g1_rem_set()->prepare_for_oops_into_collection_set_do();
   concurrent_g1_refine()->set_use_cache(false);
   concurrent_g1_refine()->clear_hot_cache_claimed_index();
@@ -5669,6 +5685,11 @@
 
   if (evacuation_failed()) {
     remove_self_forwarding_pointers();
+
+    // Reset the G1EvacuationFailureALot counters and flags
+    // Note: the values are reset only when an actual
+    // evacuation failure occurs.
+    NOT_PRODUCT(reset_evacuation_should_fail();)
   }
 
   // Enqueue any remaining references remaining on the STW

--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Thu Aug 23 10:21:12 2012 +0200
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.hpp	Tue Aug 28 15:20:08 2012 -0700
@@ -915,6 +915,39 @@
   oop handle_evacuation_failure_par(OopsInHeapRegionClosure* cl, oop obj);
   void handle_evacuation_failure_common(oop obj, markOop m);
 
+#ifndef PRODUCT
+  // Support for forcing evacuation failures. Analogous to
+  // PromotionFailureALot for the other collectors.
+
+  // Records whether G1EvacuationFailureALot should be in effect
+  // for the current GC
+  bool _evacuation_failure_alot_for_current_gc;
+
+  // Used to record the GC number for interval checking when
+  // determining whether G1EvaucationFailureALot is in effect
+  // for the current GC.
+  size_t _evacuation_failure_alot_gc_number;
+
+  // Count of the number of evacuations between failures.
+  volatile size_t _evacuation_failure_alot_count;
+
+  // Set whether G1EvacuationFailureALot should be in effect
+  // for the current GC (based upon the type of GC and which
+  // command line flags are set);
+  inline bool evacuation_failure_alot_for_gc_type(bool gcs_are_young,
+                                                  bool during_initial_mark,
+                                                  bool during_marking);
+
+  inline void set_evacuation_failure_alot_for_current_gc();
+
+  // Return true if it's time to cause an evacuation failure.
+  inline bool evacuation_should_fail();
+
+  // Reset the G1EvacuationFailureALot counters.  Should be called at
+  // the end of an evacuation pause in which an evacuation failure ocurred.
+  inline void reset_evacuation_should_fail();
+#endif // !PRODUCT
+
   // ("Weak") Reference processing support.
   //
   // G1 has 2 instances of the referece processor class. One

--- a/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.inline.hpp	Thu Aug 23 10:21:12 2012 +0200
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1CollectedHeap.inline.hpp	Tue Aug 28 15:20:08 2012 -0700
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
+ * Copyright (c) 2001, 2012, Oracle and/or its affiliates. All rights reserved.
  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  *
  * This code is free software; you can redistribute it and/or modify it
@@ -138,7 +138,7 @@
   return _task_queues->queue(i);
 }
 
-inline  bool G1CollectedHeap::isMarkedPrev(oop obj) const {
+inline bool G1CollectedHeap::isMarkedPrev(oop obj) const {
   return _cm->prevMarkBitMap()->isMarked((HeapWord *)obj);
 }
 
@@ -146,4 +146,77 @@
   return _cm->nextMarkBitMap()->isMarked((HeapWord *)obj);
 }
 
+#ifndef PRODUCT
+// Support for G1EvacuationFailureALot
+
+inline bool
+G1CollectedHeap::evacuation_failure_alot_for_gc_type(bool gcs_are_young,
+                                                     bool during_initial_mark,
+                                                     bool during_marking) {
+  bool res = false;
+  if (during_marking) {
+    res |= G1EvacuationFailureALotDuringConcMark;
+  }
+  if (during_initial_mark) {
+    res |= G1EvacuationFailureALotDuringInitialMark;
+  }
+  if (gcs_are_young) {
+    res |= G1EvacuationFailureALotDuringYoungGC;
+  } else {
+    // GCs are mixed
+    res |= G1EvacuationFailureALotDuringMixedGC;
+  }
+  return res;
+}
+
+inline void
+G1CollectedHeap::set_evacuation_failure_alot_for_current_gc() {
+  if (G1EvacuationFailureALot) {
+    // Note we can't assert that _evacuation_failure_alot_for_current_gc
+    // is clear here. It may have been set during a previous GC but that GC
+    // did not copy enough objects (i.e. G1EvacuationFailureALotCount) to
+    // trigger an evacuation failure and clear the flags and and counts.
+
+    // Check if we have gone over the interval.
+    const size_t gc_num = total_collections();
+    const size_t elapsed_gcs = gc_num - _evacuation_failure_alot_gc_number;
+
+    _evacuation_failure_alot_for_current_gc = (elapsed_gcs >= G1EvacuationFailureALotInterval);
+
+    // Now check if G1EvacuationFailureALot is enabled for the current GC type.
+    const bool gcs_are_young = g1_policy()->gcs_are_young();
+    const bool during_im = g1_policy()->during_initial_mark_pause();
+    const bool during_marking = mark_in_progress();
+
+    _evacuation_failure_alot_for_current_gc &=
+      evacuation_failure_alot_for_gc_type(gcs_are_young,
+                                          during_im,
+                                          during_marking);
+  }
+}
+
+inline bool
+G1CollectedHeap::evacuation_should_fail() {
+  if (!G1EvacuationFailureALot || !_evacuation_failure_alot_for_current_gc) {
+    return false;
+  }
+  // G1EvacuationFailureALot is in effect for current GC
+  // Access to _evacuation_failure_alot_count is not atomic;
+  // the value does not have to be exact.
+  if (++_evacuation_failure_alot_count < G1EvacuationFailureALotCount) {
+    return false;
+  }
+  _evacuation_failure_alot_count = 0;
+  return true;
+}
+
+inline void G1CollectedHeap::reset_evacuation_should_fail() {
+  if (G1EvacuationFailureALot) {
+    _evacuation_failure_alot_gc_number = total_collections();
+    _evacuation_failure_alot_count = 0;
+    _evacuation_failure_alot_for_current_gc = false;
+  }
+}
+#endif  // #ifndef PRODUCT
+
 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1COLLECTEDHEAP_INLINE_HPP

--- a/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp	Thu Aug 23 10:21:12 2012 +0200
+++ b/hotspot/src/share/vm/gc_implementation/g1/g1_globals.hpp	Tue Aug 28 15:20:08 2012 -0700
@@ -311,7 +311,35 @@
           "as a percentage of the heap size.")                              \
                                                                             \
   experimental(ccstr, G1LogLevel, NULL,                                     \
-          "Log level for G1 logging: fine, finer, finest")
+          "Log level for G1 logging: fine, finer, finest")                  \
+                                                                            \
+  notproduct(bool, G1EvacuationFailureALot, false,                          \
+          "Force use of evacuation failure handling during certain "        \
+          "evacuation pauses")                                              \
+                                                                            \
+  develop(uintx, G1EvacuationFailureALotCount, 1000,                        \
+          "Number of successful evacuations between evacuation failures "   \
+          "occurring at object copying")                                    \
+                                                                            \
+  develop(uintx, G1EvacuationFailureALotInterval, 5,                        \
+          "Total collections between forced triggering of evacuation "      \
+          "failures")                                                       \
+                                                                            \
+  develop(bool, G1EvacuationFailureALotDuringConcMark, true,                \
+          "Force use of evacuation failure handling during evacuation "     \
+          "pauses when marking is in progress")                             \
+                                                                            \
+  develop(bool, G1EvacuationFailureALotDuringInitialMark, true,             \
+          "Force use of evacuation failure handling during initial mark "   \
+          "evacuation pauses")                                              \
+                                                                            \
+  develop(bool, G1EvacuationFailureALotDuringYoungGC, true,                 \
+          "Force use of evacuation failure handling during young "          \
+          "evacuation pauses")                                              \
+                                                                            \
+  develop(bool, G1EvacuationFailureALotDuringMixedGC, true,                 \
+          "Force use of evacuation failure handling during mixed "          \
+          "evacuation pauses")
 
 G1_FLAGS(DECLARE_DEVELOPER_FLAG, DECLARE_PD_DEVELOPER_FLAG, DECLARE_PRODUCT_FLAG, DECLARE_PD_PRODUCT_FLAG, DECLARE_DIAGNOSTIC_FLAG, DECLARE_EXPERIMENTAL_FLAG, DECLARE_NOTPRODUCT_FLAG, DECLARE_MANAGEABLE_FLAG, DECLARE_PRODUCT_RW_FLAG)