1 /*

     2  * Copyright (c) 2001, 2016, Oracle and/or its affiliates. All rights reserved.

     3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.

     4  *

     5  * This code is free software; you can redistribute it and/or modify it

     6  * under the terms of the GNU General Public License version 2 only, as

     7  * published by the Free Software Foundation.

     8  *

     9  * This code is distributed in the hope that it will be useful, but WITHOUT

    10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or

    11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

    12  * version 2 for more details (a copy is included in the LICENSE file that

    13  * accompanied this code).

    14  *

    15  * You should have received a copy of the GNU General Public License version

    16  * 2 along with this work; if not, write to the Free Software Foundation,

    17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.

    18  *

    19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA

    20  * or visit www.oracle.com if you need additional information or have any

    21  * questions.

    22  *

    23  */

    24 

    25 #ifndef SHARE_VM_GC_PARALLEL_PARALLELSCAVENGEHEAP_HPP

    26 #define SHARE_VM_GC_PARALLEL_PARALLELSCAVENGEHEAP_HPP

    27 

    28 #include "gc/parallel/generationSizer.hpp"

    29 #include "gc/parallel/objectStartArray.hpp"

    30 #include "gc/parallel/psGCAdaptivePolicyCounters.hpp"

    31 #include "gc/parallel/psOldGen.hpp"

    32 #include "gc/parallel/psYoungGen.hpp"

    33 #include "gc/shared/collectedHeap.hpp"

    34 #include "gc/shared/collectorPolicy.hpp"

    35 #include "gc/shared/gcPolicyCounters.hpp"

    36 #include "gc/shared/gcWhen.hpp"

    37 #include "gc/shared/strongRootsScope.hpp"

    38 #include "memory/metaspace.hpp"

    39 #include "utilities/ostream.hpp"

    40 

    41 class AdjoiningGenerations;

    42 class GCHeapSummary;

    43 class GCTaskManager;

    44 class PSAdaptiveSizePolicy;

    45 class PSHeapSummary;

    46 

    47 class ParallelScavengeHeap : public CollectedHeap {

    48   friend class VMStructs;

    49  private:

    50   static PSYoungGen* _young_gen;

    51   static PSOldGen*   _old_gen;

    52 

    53   // Sizing policy for entire heap

    54   static PSAdaptiveSizePolicy*       _size_policy;

    55   static PSGCAdaptivePolicyCounters* _gc_policy_counters;

    56 

    57   GenerationSizer* _collector_policy;

    58 

    59   // Collection of generations that are adjacent in the

    60   // space reserved for the heap.

    61   AdjoiningGenerations* _gens;

    62   unsigned int _death_march_count;

    63 

    64   // The task manager

    65   static GCTaskManager* _gc_task_manager;

    66 

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

    68 

    69  protected:

    70   static inline size_t total_invocations();

    71   HeapWord* allocate_new_tlab(size_t size);

    72 

    73   inline bool should_alloc_in_eden(size_t size) const;

    74   inline void death_march_check(HeapWord* const result, size_t size);

    75   HeapWord* mem_allocate_old_gen(size_t size);

    76 

    77  public:

    78   ParallelScavengeHeap(GenerationSizer* policy) :

    79     CollectedHeap(), _collector_policy(policy), _death_march_count(0) { }

    80 

    81   // For use by VM operations

    82   enum CollectionType {

    83     Scavenge,

    84     MarkSweep

    85   };

    86 

    87   virtual Name kind() const {

    88     return CollectedHeap::ParallelScavengeHeap;

    89   }

    90 

    91   virtual const char* name() const {

    92     return "Parallel";

    93   }

    94 

    95   virtual CollectorPolicy* collector_policy() const { return _collector_policy; }

    96 

    97   static PSYoungGen* young_gen() { return _young_gen; }

    98   static PSOldGen* old_gen()     { return _old_gen; }

    99 

   100   virtual PSAdaptiveSizePolicy* size_policy() { return _size_policy; }

   101 

   102   static PSGCAdaptivePolicyCounters* gc_policy_counters() { return _gc_policy_counters; }

   103 

   104   static ParallelScavengeHeap* heap();

   105 

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

   107 

   108   AdjoiningGenerations* gens() { return _gens; }

   109 

   110   // Returns JNI_OK on success

   111   virtual jint initialize();

   112 

   113   void post_initialize();

   114   void update_counters();

   115 

   116   // The alignment used for the various areas

   117   size_t space_alignment()      { return _collector_policy->space_alignment(); }

   118   size_t generation_alignment() { return _collector_policy->gen_alignment(); }

   119 

   120   // Return the (conservative) maximum heap alignment

   121   static size_t conservative_max_heap_alignment() {

   122     return CollectorPolicy::compute_heap_alignment();

   123   }

   124 

   125   size_t capacity() const;

   126   size_t used() const;

   127 

   128   // Return "true" if all generations have reached the

   129   // maximal committed limit that they can reach, without a garbage

   130   // collection.

   131   virtual bool is_maximal_no_gc() const;

   132 

   133   // Return true if the reference points to an object that

   134   // can be moved in a partial collection.  For currently implemented

   135   // generational collectors that means during a collection of

   136   // the young gen.

   137   virtual bool is_scavengable(const void* addr);

   138 

   139   size_t max_capacity() const;

   140 

   141   // Whether p is in the allocated part of the heap

   142   bool is_in(const void* p) const;

   143 

   144   bool is_in_reserved(const void* p) const;

   145 

   146   bool is_in_young(oop p);  // reserved part

   147   bool is_in_old(oop p);    // reserved part

   148 

   149   // Memory allocation.   "gc_time_limit_was_exceeded" will

   150   // be set to true if the adaptive size policy determine that

   151   // an excessive amount of time is being spent doing collections

   152   // and caused a NULL to be returned.  If a NULL is not returned,

   153   // "gc_time_limit_was_exceeded" has an undefined meaning.

   154   HeapWord* mem_allocate(size_t size, bool* gc_overhead_limit_was_exceeded);

   155 

   156   // Allocation attempt(s) during a safepoint. It should never be called

   157   // to allocate a new TLAB as this allocation might be satisfied out

   158   // of the old generation.

   159   HeapWord* failed_mem_allocate(size_t size);

   160 

   161   // Support for System.gc()

   162   void collect(GCCause::Cause cause);

   163 

   164   // These also should be called by the vm thread at a safepoint (e.g., from a

   165   // VM operation).

   166   //

   167   // The first collects the young generation only, unless the scavenge fails; it

   168   // will then attempt a full gc.  The second collects the entire heap; if

   169   // maximum_compaction is true, it will compact everything and clear all soft

   170   // references.

   171   inline void invoke_scavenge();

   172 

   173   // Perform a full collection

   174   virtual void do_full_collection(bool clear_all_soft_refs);

   175 

   176   bool supports_inline_contig_alloc() const { return !UseNUMA; }

   177 

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

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

   180 

   181   void ensure_parsability(bool retire_tlabs);

   182   void accumulate_statistics_all_tlabs();

   183   void resize_all_tlabs();

   184 

   185   bool supports_tlab_allocation() const { return true; }

   186 

   187   size_t tlab_capacity(Thread* thr) const;

   188   size_t tlab_used(Thread* thr) const;

   189   size_t unsafe_max_tlab_alloc(Thread* thr) const;

   190 

   191   // Can a compiler initialize a new object without store barriers?

   192   // This permission only extends from the creation of a new object

   193   // via a TLAB up to the first subsequent safepoint.

   194   virtual bool can_elide_tlab_store_barriers() const {

   195     return true;

   196   }

   197 

   198   virtual bool card_mark_must_follow_store() const {

   199     return false;

   200   }

   201 

   202   // Return true if we don't we need a store barrier for

   203   // initializing stores to an object at this address.

   204   virtual bool can_elide_initializing_store_barrier(oop new_obj);

   205 

   206   void object_iterate(ObjectClosure* cl);

   207   void safe_object_iterate(ObjectClosure* cl) { object_iterate(cl); }

   208 

   209   HeapWord* block_start(const void* addr) const;

   210   size_t block_size(const HeapWord* addr) const;

   211   bool block_is_obj(const HeapWord* addr) const;

   212 

   213   jlong millis_since_last_gc();

   214 

   215   void prepare_for_verify();

   216   PSHeapSummary create_ps_heap_summary();

   217   virtual void print_on(outputStream* st) const;

   218   virtual void print_on_error(outputStream* st) const;

   219   virtual void print_gc_threads_on(outputStream* st) const;

   220   virtual void gc_threads_do(ThreadClosure* tc) const;

   221   virtual void print_tracing_info() const;

   222 

   223   void verify(VerifyOption option /* ignored */);

   224 

   225   // Resize the young generation.  The reserved space for the

   226   // generation may be expanded in preparation for the resize.

   227   void resize_young_gen(size_t eden_size, size_t survivor_size);

   228 

   229   // Resize the old generation.  The reserved space for the

   230   // generation may be expanded in preparation for the resize.

   231   void resize_old_gen(size_t desired_free_space);

   232 

   233   // Save the tops of the spaces in all generations

   234   void record_gen_tops_before_GC() PRODUCT_RETURN;

   235 

   236   // Mangle the unused parts of all spaces in the heap

   237   void gen_mangle_unused_area() PRODUCT_RETURN;

   238 

   239   // Call these in sequential code around the processing of strong roots.

   240   class ParStrongRootsScope : public MarkScope {

   241    public:

   242     ParStrongRootsScope();

   243     ~ParStrongRootsScope();

   244   };

   245 };

   246 

   247 // Simple class for storing info about the heap at the start of GC, to be used

   248 // after GC for comparison/printing.

   249 class PreGCValues {

   250 public:

   251   PreGCValues(ParallelScavengeHeap* heap) :

   252       _heap_used(heap->used()),

   253       _young_gen_used(heap->young_gen()->used_in_bytes()),

   254       _old_gen_used(heap->old_gen()->used_in_bytes()),

   255       _metadata_used(MetaspaceAux::used_bytes()) { };

   256 

   257   size_t heap_used() const      { return _heap_used; }

   258   size_t young_gen_used() const { return _young_gen_used; }

   259   size_t old_gen_used() const   { return _old_gen_used; }

   260   size_t metadata_used() const  { return _metadata_used; }

   261 

   262 private:

   263   size_t _heap_used;

   264   size_t _young_gen_used;

   265   size_t _old_gen_used;

   266   size_t _metadata_used;

   267 };

   268 

   269 // Class that can be used to print information about the

   270 // adaptive size policy at intervals specified by

   271 // AdaptiveSizePolicyOutputInterval.  Only print information

   272 // if an adaptive size policy is in use.

   273 class AdaptiveSizePolicyOutput : AllStatic {

   274   static bool enabled() {

   275     return UseParallelGC &&

   276            UseAdaptiveSizePolicy &&

   277            log_is_enabled(Debug, gc, ergo);

   278   }

   279  public:

   280   static void print() {

   281     if (enabled()) {

   282       ParallelScavengeHeap::heap()->size_policy()->print();

   283     }

   284   }

   285 

   286   static void print(AdaptiveSizePolicy* size_policy, uint count) {

   287     bool do_print =

   288         enabled() &&

   289         (AdaptiveSizePolicyOutputInterval > 0) &&

   290         (count % AdaptiveSizePolicyOutputInterval) == 0;

   291 

   292     if (do_print) {

   293       size_policy->print();

   294     }

   295   }

   296 };

   297 

   298 #endif // SHARE_VM_GC_PARALLEL_PARALLELSCAVENGEHEAP_HPP