8268556: Use bitmap for storing regions that failed evacuation

Reviewed-by: kbarrett, iwalulya, sjohanss

Author: Thomas Schatzl

src/hotspot/share/gc/g1/g1CollectedHeap.cpp

@@ -1477,7 +1477,7 @@ G1CollectedHeap::G1CollectedHeap() :
   _cr(NULL),
   _task_queues(NULL),
   _num_regions_failed_evacuation(0),
-  _regions_failed_evacuation(NULL),
+  _regions_failed_evacuation(mtGC),
   _evacuation_failed_info_array(NULL),
   _preserved_marks_set(true /* in_c_heap */),
 #ifndef PRODUCT
@@ -1770,7 +1770,7 @@ jint G1CollectedHeap::initialize() {
 
   _collection_set.initialize(max_reserved_regions());
 
-  _regions_failed_evacuation = NEW_C_HEAP_ARRAY(volatile bool, max_regions(), mtGC);
+  _regions_failed_evacuation.resize(max_regions());
 
   G1InitLogger::print();
 
@@ -3470,7 +3470,7 @@ void G1CollectedHeap::pre_evacuate_collection_set(G1EvacuationInfo& evacuation_i
   _expand_heap_after_alloc_failure = true;
   Atomic::store(&_num_regions_failed_evacuation, 0u);
 
-  memset((void*)_regions_failed_evacuation, false, sizeof(bool) * max_regions());
+  _regions_failed_evacuation.clear();
 
   // Disable the hot card cache.
   _hot_card_cache->reset_hot_cache_claimed_index();

src/hotspot/share/gc/g1/g1CollectedHeap.hpp

@@ -55,6 +55,7 @@
 #include "gc/shared/softRefPolicy.hpp"
 #include "gc/shared/taskqueue.hpp"
 #include "memory/memRegion.hpp"
+#include "utilities/bitMap.hpp"
 #include "utilities/stack.hpp"
 
 // A "G1CollectedHeap" is an implementation of a java heap for HotSpot.
@@ -868,7 +869,7 @@ class G1CollectedHeap : public CollectedHeap {
   // Number of regions evacuation failed in the current collection.
   volatile uint _num_regions_failed_evacuation;
   // Records for every region on the heap whether evacuation failed for it.
-  volatile bool* _regions_failed_evacuation;
+  CHeapBitMap _regions_failed_evacuation;
 
   EvacuationFailedInfo* _evacuation_failed_info_array;
 

src/hotspot/share/gc/g1/g1CollectedHeap.inline.hpp

@@ -37,6 +37,7 @@
 #include "gc/shared/markBitMap.inline.hpp"
 #include "gc/shared/taskqueue.inline.hpp"
 #include "runtime/atomic.hpp"
+#include "utilities/bitMap.inline.hpp"
 
 G1GCPhaseTimes* G1CollectedHeap::phase_times() const {
   return _policy->phase_times();
@@ -195,20 +196,15 @@ bool G1CollectedHeap::evacuation_failed() const {
 }
 
 bool G1CollectedHeap::evacuation_failed(uint region_idx) const {
-  assert(region_idx < max_regions(), "Invalid region index %u", region_idx);
-
-  return Atomic::load(&_regions_failed_evacuation[region_idx]);
+  return _regions_failed_evacuation.par_at(region_idx, memory_order_relaxed);
 }
 
 uint G1CollectedHeap::num_regions_failed_evacuation() const {
   return Atomic::load(&_num_regions_failed_evacuation);
 }
 
 bool G1CollectedHeap::notify_region_failed_evacuation(uint const region_idx) {
-  assert(region_idx < max_regions(), "Invalid region index %u", region_idx);
-
-  volatile bool* region_failed_addr = &_regions_failed_evacuation[region_idx];
-  bool result = !Atomic::load(region_failed_addr) && !Atomic::cmpxchg(region_failed_addr, false, true, memory_order_relaxed);
+  bool result = _regions_failed_evacuation.par_set_bit(region_idx, memory_order_relaxed);
   if (result) {
     Atomic::inc(&_num_regions_failed_evacuation, memory_order_relaxed);
   }