src/hotspot/share/memory/heapInspection.cpp

*** 235,244 ****
--- 235,280 ----
  
  size_t KlassInfoTable::size_of_instances_in_words() const {
    return _size_of_instances_in_words;
  }
  
+ // Return false if the entry could not be recorded on account
+ // of running out of space required to create a new entry.
+ bool KlassInfoTable::merge_entry(const KlassInfoEntry* cie) {
+   Klass*        k = cie->klass();
+   KlassInfoEntry* elt = lookup(k);
+   // elt may be NULL if it's a new klass for which we
+   // could not allocate space for a new entry in the hashtable.
+   if (elt != NULL) {
+     elt->set_count(elt->count() + cie->count());
+     elt->set_words(elt->words() + cie->words());
+     _size_of_instances_in_words += cie->words();
+     return true;
+   } else {
+     return false;
+   }
+ }
+ 
+ class KlassInfoTableMergeClosure : public KlassInfoClosure {
+ private:
+   KlassInfoTable* _dest;
+   bool _success;
+ public:
+   KlassInfoTableMergeClosure(KlassInfoTable* table) : _dest(table), _success(true) {}
+   void do_cinfo(KlassInfoEntry* cie) {
+     _success &= _dest->merge_entry(cie);
+   }
+   bool is_success() { return _success; }
+ };
+ 
+ // merge from table
+ bool KlassInfoTable::merge(KlassInfoTable* table) {
+   KlassInfoTableMergeClosure closure(this);
+   table->iterate(&closure);
+   return closure.is_success();
+ }
+ 
  int KlassInfoHisto::sort_helper(KlassInfoEntry** e1, KlassInfoEntry** e2) {
    return (*e1)->compare(*e1,*e2);
  }
  
  KlassInfoHisto::KlassInfoHisto(KlassInfoTable* cit) :
*** 502,526 ****
    bool should_visit(oop obj) {
      return _filter == NULL || _filter->do_object_b(obj);
    }
  };
  
! size_t HeapInspection::populate_table(KlassInfoTable* cit, BoolObjectClosure *filter) {
    ResourceMark rm;
  
    RecordInstanceClosure ric(cit, filter);
    Universe::heap()->object_iterate(&ric);
    return ric.missed_count();
  }
  
! void HeapInspection::heap_inspection(outputStream* st) {
    ResourceMark rm;
  
    KlassInfoTable cit(false);
    if (!cit.allocation_failed()) {
      // populate table with object allocation info
!     size_t missed_count = populate_table(&cit);
      if (missed_count != 0) {
        log_info(gc, classhisto)("WARNING: Ran out of C-heap; undercounted " SIZE_FORMAT
                                 " total instances in data below",
                                 missed_count);
      }
--- 538,613 ----
    bool should_visit(oop obj) {
      return _filter == NULL || _filter->do_object_b(obj);
    }
  };
  
! // Heap inspection for every worker.
! // When native OOM hanppens for KlassInfoTable, set _success to false.
! // TODO(?) it seems atomically set/get _success is unnecessary becasue it
! // is set to true at constructor and can only be set to false here.
! // the only risk seems a worker may continue inspect heap when another
! // worker set _success to false, but this is OK because the current worker
! // doesn't change _success if everything is OK for it's inpection work, and
! // the _success will be false finally and serial heap inpection can be tried.
! void ParHeapInspectTask::work(uint worker_id) {
!   size_t missed_count = 0;
!   if (!_success) {
!     // other worker has failed on parallel iteration.
!     return;
!   }
! 
!   KlassInfoTable cit(false);
!   if (!cit.allocation_failed()) {
!     RecordInstanceClosure ric(&cit, _filter);
!     _poi->object_iterate(&ric, worker_id);
!     missed_count = ric.missed_count();
!   } else {
!     // fail to allocate memory, stop parallel mode.
!     _success = false;
!     return;
!   }
!   {
!     MutexLocker x(&_mutex);
! 
!     if (!_shared_cit->merge(&cit)) {
!       _success = false;
!       return;
!     }
!     _shared_missed_count += missed_count;
!   }
! }
! 
! size_t HeapInspection::populate_table(KlassInfoTable* cit, BoolObjectClosure *filter, size_t parallel_thread_num) {
    ResourceMark rm;
  
+   // Try parallel first.
+   if (parallel_thread_num > 1) {
+     ParallelObjectIterator* poi = Universe::heap()->parallel_object_iterator(parallel_thread_num);
+     if (poi != NULL) {
+       ParHeapInspectTask task(poi, cit, filter);
+       Universe::heap()->run_task(&task);
+       delete poi;
+       if (task.success()) {
+         return task.missed_count();
+       }
+     }
+   }
+ 
+   // If no parallel iteration available, run serially.
    RecordInstanceClosure ric(cit, filter);
    Universe::heap()->object_iterate(&ric);
    return ric.missed_count();
  }
  
! void HeapInspection::heap_inspection(outputStream* st, size_t parallel_thread_num) {
    ResourceMark rm;
  
    KlassInfoTable cit(false);
    if (!cit.allocation_failed()) {
+     size_t missed_count = 0;;
      // populate table with object allocation info
!     missed_count = populate_table(&cit, NULL, parallel_thread_num);
      if (missed_count != 0) {
        log_info(gc, classhisto)("WARNING: Ran out of C-heap; undercounted " SIZE_FORMAT
                                 " total instances in data below",
                                 missed_count);
      }