view src/share/vm/gc_implementation/parallelScavenge/parallelScavengeHeap.hpp @ 5761:b86041bd7b99

8010722: assert: failed: heap size is too big for compressed oops Summary: Use conservative assumptions of required alignment for the various garbage collector components into account when determining the maximum heap size that supports compressed oops. Using this conservative value avoids several circular dependencies in the calculation. Reviewed-by: stefank, dholmes
author tschatzl
date Tue, 18 Apr 2017 06:37:32 +0100
parents 63085fd28f10
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 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
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 * questions.


#include "gc_implementation/parallelScavenge/objectStartArray.hpp"
#include "gc_implementation/parallelScavenge/psGCAdaptivePolicyCounters.hpp"
#include "gc_implementation/parallelScavenge/psOldGen.hpp"
#include "gc_implementation/parallelScavenge/psPermGen.hpp"
#include "gc_implementation/parallelScavenge/psYoungGen.hpp"
#include "gc_implementation/shared/gcPolicyCounters.hpp"
#include "gc_interface/collectedHeap.inline.hpp"
#include "utilities/ostream.hpp"

class AdjoiningGenerations;
class CollectorPolicy;
class GCHeapSummary;
class GCTaskManager;
class GenerationSizer;
class CollectorPolicy;
class PSAdaptiveSizePolicy;
class PSHeapSummary;
class VirtualSpaceSummary;

class ParallelScavengeHeap : public CollectedHeap {
  friend class VMStructs;
  static PSYoungGen* _young_gen;
  static PSOldGen*   _old_gen;
  static PSPermGen*  _perm_gen;

  // Sizing policy for entire heap
  static PSAdaptiveSizePolicy* _size_policy;
  static PSGCAdaptivePolicyCounters*   _gc_policy_counters;

  static ParallelScavengeHeap* _psh;

  size_t _perm_gen_alignment;
  size_t _young_gen_alignment;
  size_t _old_gen_alignment;

  GenerationSizer* _collector_policy;

  inline size_t set_alignment(size_t& var, size_t val);

  // Collection of generations that are adjacent in the
  // space reserved for the heap.
  AdjoiningGenerations* _gens;
  unsigned int _death_march_count;

  static GCTaskManager*          _gc_task_manager;      // The task manager.

  void trace_heap(GCWhen::Type when, GCTracer* tracer);

  static inline size_t total_invocations();
  HeapWord* allocate_new_tlab(size_t size);

  inline bool should_alloc_in_eden(size_t size) const;
  inline void death_march_check(HeapWord* const result, size_t size);
  HeapWord* mem_allocate_old_gen(size_t size);

  ParallelScavengeHeap() : CollectedHeap() {
    _death_march_count = 0;
    set_alignment(_perm_gen_alignment, intra_heap_alignment());
    set_alignment(_young_gen_alignment, intra_heap_alignment());
    set_alignment(_old_gen_alignment, intra_heap_alignment());

  // Return the (conservative) maximum heap alignment
  static size_t conservative_max_heap_alignment() {
    return intra_heap_alignment();

  // For use by VM operations
  enum CollectionType {

  ParallelScavengeHeap::Name kind() const {
    return CollectedHeap::ParallelScavengeHeap;

CollectorPolicy* collector_policy() const { return (CollectorPolicy*) _collector_policy; }
  // GenerationSizer* collector_policy() const { return _collector_policy; }

  static PSYoungGen* young_gen()     { return _young_gen; }
  static PSOldGen* old_gen()         { return _old_gen; }
  static PSPermGen* perm_gen()       { return _perm_gen; }

  virtual PSAdaptiveSizePolicy* size_policy() { return _size_policy; }

  static PSGCAdaptivePolicyCounters* gc_policy_counters() { return _gc_policy_counters; }

  static ParallelScavengeHeap* heap();

  static GCTaskManager* const gc_task_manager() { return _gc_task_manager; }

  AdjoiningGenerations* gens() { return _gens; }

  // Returns JNI_OK on success
  virtual jint initialize();

  void post_initialize();
  void update_counters();
  // The alignment used for the various generations.
  size_t perm_gen_alignment()  const { return _perm_gen_alignment; }
  size_t young_gen_alignment() const { return _young_gen_alignment; }
  size_t old_gen_alignment()  const { return _old_gen_alignment; }

  // The alignment used for eden and survivors within the young gen
  // and for boundary between young gen and old gen.
  static size_t intra_heap_alignment() { return 64 * K * HeapWordSize; }

  size_t capacity() const;
  size_t used() const;

  // Return "true" if all generations (but perm) have reached the
  // maximal committed limit that they can reach, without a garbage
  // collection.
  virtual bool is_maximal_no_gc() const;

  // Return true if the reference points to an object that
  // can be moved in a partial collection.  For currently implemented
  // generational collectors that means during a collection of
  // the young gen.
  virtual bool is_scavengable(const void* addr);

  // Does this heap support heap inspection? (+PrintClassHistogram)
  bool supports_heap_inspection() const { return true; }

  size_t permanent_capacity() const;
  size_t permanent_used() const;

  size_t max_capacity() const;

  // Whether p is in the allocated part of the heap
  bool is_in(const void* p) const;

  bool is_in_reserved(const void* p) const;
  bool is_in_permanent(const void *p) const {    // reserved part
    return perm_gen()->reserved().contains(p);

#ifdef ASSERT
  virtual bool is_in_partial_collection(const void *p);

  bool is_permanent(const void *p) const {    // committed part
    return perm_gen()->is_in(p);

  inline bool is_in_young(oop p);        // reserved part
  inline bool is_in_old_or_perm(oop p);  // reserved part

  // Memory allocation.   "gc_time_limit_was_exceeded" will
  // be set to true if the adaptive size policy determine that
  // an excessive amount of time is being spent doing collections
  // and caused a NULL to be returned.  If a NULL is not returned,
  // "gc_time_limit_was_exceeded" has an undefined meaning.
  HeapWord* mem_allocate(size_t size,
                         bool* gc_overhead_limit_was_exceeded);

  // Allocation attempt(s) during a safepoint. It should never be called
  // to allocate a new TLAB as this allocation might be satisfied out
  // of the old generation.
  HeapWord* failed_mem_allocate(size_t size);

  HeapWord* permanent_mem_allocate(size_t size);
  HeapWord* failed_permanent_mem_allocate(size_t size);

  // Support for System.gc()
  void collect(GCCause::Cause cause);

  // This interface assumes that it's being called by the
  // vm thread. It collects the heap assuming that the
  // heap lock is already held and that we are executing in
  // the context of the vm thread.
  void collect_as_vm_thread(GCCause::Cause cause);

  // These also should be called by the vm thread at a safepoint (e.g., from a
  // VM operation).
  // The first collects the young generation only, unless the scavenge fails; it
  // will then attempt a full gc.  The second collects the entire heap; if
  // maximum_compaction is true, it will compact everything and clear all soft
  // references.
  inline void invoke_scavenge();
  inline void invoke_full_gc(bool maximum_compaction);

  bool supports_inline_contig_alloc() const { return !UseNUMA; }

  HeapWord** top_addr() const { return !UseNUMA ? young_gen()->top_addr() : (HeapWord**)-1; }
  HeapWord** end_addr() const { return !UseNUMA ? young_gen()->end_addr() : (HeapWord**)-1; }

  void ensure_parsability(bool retire_tlabs);
  void accumulate_statistics_all_tlabs();
  void resize_all_tlabs();

  size_t unsafe_max_alloc();

  bool supports_tlab_allocation() const { return true; }

  size_t tlab_capacity(Thread* thr) const;
  size_t unsafe_max_tlab_alloc(Thread* thr) const;

  // Can a compiler initialize a new object without store barriers?
  // This permission only extends from the creation of a new object
  // via a TLAB up to the first subsequent safepoint.
  virtual bool can_elide_tlab_store_barriers() const {
    return true;

  virtual bool card_mark_must_follow_store() const {
    return false;

  // Return true if we don't we need a store barrier for
  // initializing stores to an object at this address.
  virtual bool can_elide_initializing_store_barrier(oop new_obj);

  // Can a compiler elide a store barrier when it writes
  // a permanent oop into the heap?  Applies when the compiler
  // is storing x to the heap, where x->is_perm() is true.
  virtual bool can_elide_permanent_oop_store_barriers() const {
    return true;

  void oop_iterate(OopClosure* cl);
  void object_iterate(ObjectClosure* cl);
  void safe_object_iterate(ObjectClosure* cl) { object_iterate(cl); }
  void permanent_oop_iterate(OopClosure* cl);
  void permanent_object_iterate(ObjectClosure* cl);

  HeapWord* block_start(const void* addr) const;
  size_t block_size(const HeapWord* addr) const;
  bool block_is_obj(const HeapWord* addr) const;

  jlong millis_since_last_gc();

  void prepare_for_verify();
  PSHeapSummary create_ps_heap_summary();
  VirtualSpaceSummary create_perm_gen_space_summary();
  virtual void print_on(outputStream* st) const;
  virtual void print_gc_threads_on(outputStream* st) const;
  virtual void gc_threads_do(ThreadClosure* tc) const;
  virtual void print_tracing_info() const;

  void verify(bool silent, VerifyOption option /* ignored */);

  void print_heap_change(size_t prev_used);

  // Resize the young generation.  The reserved space for the
  // generation may be expanded in preparation for the resize.
  void resize_young_gen(size_t eden_size, size_t survivor_size);

  // Resize the old generation.  The reserved space for the
  // generation may be expanded in preparation for the resize.
  void resize_old_gen(size_t desired_free_space);

  // Save the tops of the spaces in all generations
  void record_gen_tops_before_GC() PRODUCT_RETURN;

  // Mangle the unused parts of all spaces in the heap
  void gen_mangle_unused_area() PRODUCT_RETURN;

  // Call these in sequential code around the processing of strong roots.
  class ParStrongRootsScope : public MarkingCodeBlobClosure::MarkScope {

inline size_t ParallelScavengeHeap::set_alignment(size_t& var, size_t val)
  assert(is_power_of_2((intptr_t)val), "must be a power of 2");
  var = round_to(val, intra_heap_alignment());
  return var;