view src/share/vm/memory/collectorPolicy.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 d2a62e0f25eb
line wrap: on
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 * published by the Free Software Foundation.
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 * 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.
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 * questions.


#include "memory/barrierSet.hpp"
#include "memory/genRemSet.hpp"
#include "memory/permGen.hpp"

// This class (or more correctly, subtypes of this class)
// are used to define global garbage collector attributes.
// This includes initialization of generations and any other
// shared resources they may need.
// In general, all flag adjustment and validation should be
// done in initialize_flags(), which is called prior to
// initialize_size_info().
// This class is not fully developed yet. As more collector(s)
// are added, it is expected that we will come across further
// behavior that requires global attention. The correct place
// to deal with those issues is this class.

// Forward declarations.
class GenCollectorPolicy;
class TwoGenerationCollectorPolicy;
class AdaptiveSizePolicy;
#ifndef SERIALGC
class ConcurrentMarkSweepPolicy;
class G1CollectorPolicy;
#endif // SERIALGC

class GCPolicyCounters;
class PermanentGenerationSpec;
class MarkSweepPolicy;

class CollectorPolicy : public CHeapObj<mtGC> {
  PermanentGenerationSpec *_permanent_generation;
  GCPolicyCounters* _gc_policy_counters;

  // Requires that the concrete subclass sets the alignment constraints
  // before calling.
  virtual void initialize_flags();
  virtual void initialize_size_info();
  // Initialize "_permanent_generation" to a spec for the given kind of
  // Perm Gen.
  void initialize_perm_generation(PermGen::Name pgnm);

  size_t _initial_heap_byte_size;
  size_t _max_heap_byte_size;
  size_t _min_heap_byte_size;

  size_t _min_alignment;
  size_t _max_alignment;

  // The sizing of the heap are controlled by a sizing policy.
  AdaptiveSizePolicy* _size_policy;

  // Set to true when policy wants soft refs cleared.
  // Reset to false by gc after it clears all soft refs.
  bool _should_clear_all_soft_refs;
  // Set to true by the GC if the just-completed gc cleared all
  // softrefs.  This is set to true whenever a gc clears all softrefs, and
  // set to false each time gc returns to the mutator.  For example, in the
  // ParallelScavengeHeap case the latter would be done toward the end of
  // mem_allocate() where it returns op.result()
  bool _all_soft_refs_clear;

  CollectorPolicy() :

  // Return maximum heap alignment that may be imposed by the policy
  static size_t compute_max_alignment();

  void set_min_alignment(size_t align)         { _min_alignment = align; }
  size_t min_alignment()                       { return _min_alignment; }
  void set_max_alignment(size_t align)         { _max_alignment = align; }
  size_t max_alignment()                       { return _max_alignment; }

  size_t initial_heap_byte_size() { return _initial_heap_byte_size; }
  void set_initial_heap_byte_size(size_t v) { _initial_heap_byte_size = v; }
  size_t max_heap_byte_size()     { return _max_heap_byte_size; }
  void set_max_heap_byte_size(size_t v) { _max_heap_byte_size = v; }
  size_t min_heap_byte_size()     { return _min_heap_byte_size; }
  void set_min_heap_byte_size(size_t v) { _min_heap_byte_size = v; }

  enum Name {

  AdaptiveSizePolicy* size_policy() { return _size_policy; }
  bool should_clear_all_soft_refs() { return _should_clear_all_soft_refs; }
  void set_should_clear_all_soft_refs(bool v) { _should_clear_all_soft_refs = v; }
  // Returns the current value of _should_clear_all_soft_refs.
  // _should_clear_all_soft_refs is set to false as a side effect.
  bool use_should_clear_all_soft_refs(bool v);
  bool all_soft_refs_clear() { return _all_soft_refs_clear; }
  void set_all_soft_refs_clear(bool v) { _all_soft_refs_clear = v; }

  // Called by the GC after Soft Refs have been cleared to indicate
  // that the request in _should_clear_all_soft_refs has been fulfilled.
  void cleared_all_soft_refs();

  // Identification methods.
  virtual GenCollectorPolicy*           as_generation_policy()            { return NULL; }
  virtual TwoGenerationCollectorPolicy* as_two_generation_policy()        { return NULL; }
  virtual MarkSweepPolicy*              as_mark_sweep_policy()            { return NULL; }
#ifndef SERIALGC
  virtual ConcurrentMarkSweepPolicy*    as_concurrent_mark_sweep_policy() { return NULL; }
  virtual G1CollectorPolicy*            as_g1_policy()                    { return NULL; }
#endif // SERIALGC
  // Note that these are not virtual.
  bool is_generation_policy()            { return as_generation_policy() != NULL; }
  bool is_two_generation_policy()        { return as_two_generation_policy() != NULL; }
  bool is_mark_sweep_policy()            { return as_mark_sweep_policy() != NULL; }
#ifndef SERIALGC
  bool is_concurrent_mark_sweep_policy() { return as_concurrent_mark_sweep_policy() != NULL; }
  bool is_g1_policy()                    { return as_g1_policy() != NULL; }
#else  // SERIALGC
  bool is_concurrent_mark_sweep_policy() { return false; }
  bool is_g1_policy()                    { return false; }
#endif // SERIALGC

  virtual PermanentGenerationSpec *permanent_generation() {
    assert(_permanent_generation != NULL, "Sanity check");
    return _permanent_generation;

  virtual BarrierSet::Name barrier_set_name() = 0;
  virtual GenRemSet::Name  rem_set_name() = 0;

  // Create the remembered set (to cover the given reserved region,
  // allowing breaking up into at most "max_covered_regions").
  virtual GenRemSet* create_rem_set(MemRegion reserved,
                                    int max_covered_regions);

  // This method controls how a collector satisfies a request
  // for a block of memory.  "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.
  virtual HeapWord* mem_allocate_work(size_t size,
                                      bool is_tlab,
                                      bool* gc_overhead_limit_was_exceeded) = 0;

  // This method controls how a collector handles one or more
  // of its generations being fully allocated.
  virtual HeapWord *satisfy_failed_allocation(size_t size, bool is_tlab) = 0;
  // Performace Counter support
  GCPolicyCounters* counters()     { return _gc_policy_counters; }

  // Create the jstat counters for the GC policy.  By default, policy's
  // don't have associated counters, and we complain if this is invoked.
  virtual void initialize_gc_policy_counters() {

  virtual CollectorPolicy::Name kind() {
    return CollectorPolicy::CollectorPolicyKind;

  // Returns true if a collector has eden space with soft end.
  virtual bool has_soft_ended_eden() {
    return false;


class ClearedAllSoftRefs : public StackObj {
  bool _clear_all_soft_refs;
  CollectorPolicy* _collector_policy;
  ClearedAllSoftRefs(bool clear_all_soft_refs,
                     CollectorPolicy* collector_policy) :
    _collector_policy(collector_policy) {}

  ~ClearedAllSoftRefs() {
    if (_clear_all_soft_refs) {

class GenCollectorPolicy : public CollectorPolicy {
  size_t _min_gen0_size;
  size_t _initial_gen0_size;
  size_t _max_gen0_size;

  GenerationSpec **_generations;

  // Return true if an allocation should be attempted in the older
  // generation if it fails in the younger generation.  Return
  // false, otherwise.
  virtual bool should_try_older_generation_allocation(size_t word_size) const;

  void initialize_flags();
  void initialize_size_info();

  // Try to allocate space by expanding the heap.
  virtual HeapWord* expand_heap_and_allocate(size_t size, bool is_tlab);

 // Scale the base_size by NewRation according to
 //     result = base_size / (NewRatio + 1)
 // and align by min_alignment()
 size_t scale_by_NewRatio_aligned(size_t base_size);

 // Bound the value by the given maximum minus the
 // min_alignment.
 size_t bound_minus_alignment(size_t desired_size, size_t maximum_size);

  // Accessors
  size_t min_gen0_size() { return _min_gen0_size; }
  void set_min_gen0_size(size_t v) { _min_gen0_size = v; }
  size_t initial_gen0_size() { return _initial_gen0_size; }
  void set_initial_gen0_size(size_t v) { _initial_gen0_size = v; }
  size_t max_gen0_size() { return _max_gen0_size; }
  void set_max_gen0_size(size_t v) { _max_gen0_size = v; }

  virtual int number_of_generations() = 0;

  virtual GenerationSpec **generations()       {
    assert(_generations != NULL, "Sanity check");
    return _generations;

  virtual GenCollectorPolicy* as_generation_policy() { return this; }

  virtual void initialize_generations() = 0;

  virtual void initialize_all() {

  HeapWord* mem_allocate_work(size_t size,
                              bool is_tlab,
                              bool* gc_overhead_limit_was_exceeded);

  HeapWord *satisfy_failed_allocation(size_t size, bool is_tlab);

  // Adaptive size policy
  virtual void initialize_size_policy(size_t init_eden_size,
                                      size_t init_promo_size,
                                      size_t init_survivor_size);

// All of hotspot's current collectors are subtypes of this
// class. Currently, these collectors all use the same gen[0],
// but have different gen[1] types. If we add another subtype
// of CollectorPolicy, this class should be broken out into
// its own file.

class TwoGenerationCollectorPolicy : public GenCollectorPolicy {
  size_t _min_gen1_size;
  size_t _initial_gen1_size;
  size_t _max_gen1_size;

  void initialize_flags();
  void initialize_size_info();
  void initialize_generations()                { ShouldNotReachHere(); }

  // Accessors
  size_t min_gen1_size() { return _min_gen1_size; }
  void set_min_gen1_size(size_t v) { _min_gen1_size = v; }
  size_t initial_gen1_size() { return _initial_gen1_size; }
  void set_initial_gen1_size(size_t v) { _initial_gen1_size = v; }
  size_t max_gen1_size() { return _max_gen1_size; }
  void set_max_gen1_size(size_t v) { _max_gen1_size = v; }

  // Inherited methods
  TwoGenerationCollectorPolicy* as_two_generation_policy() { return this; }

  int number_of_generations()                  { return 2; }
  BarrierSet::Name barrier_set_name()          { return BarrierSet::CardTableModRef; }
  GenRemSet::Name rem_set_name()               { return GenRemSet::CardTable; }

  virtual CollectorPolicy::Name kind() {
    return CollectorPolicy::TwoGenerationCollectorPolicyKind;

  // Returns true is gen0 sizes were adjusted
  bool adjust_gen0_sizes(size_t* gen0_size_ptr, size_t* gen1_size_ptr,
                               size_t heap_size, size_t min_gen1_size);

class MarkSweepPolicy : public TwoGenerationCollectorPolicy {
  void initialize_generations();


  MarkSweepPolicy* as_mark_sweep_policy() { return this; }

  void initialize_gc_policy_counters();