1 /*

     2  * Copyright (c) 2002, 2015, 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_PSPROMOTIONMANAGER_HPP

    26 #define SHARE_VM_GC_PARALLEL_PSPROMOTIONMANAGER_HPP

    27 

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

    29 #include "gc/shared/copyFailedInfo.hpp"

    30 #include "gc/shared/gcTrace.hpp"

    31 #include "gc/shared/taskqueue.hpp"

    32 #include "memory/allocation.hpp"

    33 #include "memory/padded.hpp"

    34 #include "utilities/globalDefinitions.hpp"

    35 

    36 //

    37 // psPromotionManager is used by a single thread to manage object survival

    38 // during a scavenge. The promotion manager contains thread local data only.

    39 //

    40 // NOTE! Be careful when allocating the stacks on cheap. If you are going

    41 // to use a promotion manager in more than one thread, the stacks MUST be

    42 // on cheap. This can lead to memory leaks, though, as they are not auto

    43 // deallocated.

    44 //

    45 // FIX ME FIX ME Add a destructor, and don't rely on the user to drain/flush/deallocate!

    46 //

    47 

    48 class MutableSpace;

    49 class PSOldGen;

    50 class ParCompactionManager;

    51 

    52 class PSPromotionManager VALUE_OBJ_CLASS_SPEC {

    53   friend class PSScavenge;

    54   friend class PSRefProcTaskExecutor;

    55  private:

    56   static PaddedEnd<PSPromotionManager>* _manager_array;

    57   static OopStarTaskQueueSet*           _stack_array_depth;

    58   static PSOldGen*                      _old_gen;

    59   static MutableSpace*                  _young_space;

    60 

    61 #if TASKQUEUE_STATS

    62   size_t                              _masked_pushes;

    63   size_t                              _masked_steals;

    64   size_t                              _arrays_chunked;

    65   size_t                              _array_chunks_processed;

    66 

    67   void print_local_stats(outputStream* const out, uint i) const;

    68   static void print_taskqueue_stats(outputStream* const out = gclog_or_tty);

    69 

    70   void reset_stats();

    71 #endif // TASKQUEUE_STATS

    72 

    73   PSYoungPromotionLAB                 _young_lab;

    74   PSOldPromotionLAB                   _old_lab;

    75   bool                                _young_gen_is_full;

    76   bool                                _old_gen_is_full;

    77 

    78   OopStarTaskQueue                    _claimed_stack_depth;

    79   OverflowTaskQueue<oop, mtGC>        _claimed_stack_breadth;

    80 

    81   bool                                _totally_drain;

    82   uint                                _target_stack_size;

    83 

    84   uint                                _array_chunk_size;

    85   uint                                _min_array_size_for_chunking;

    86 

    87   PromotionFailedInfo                 _promotion_failed_info;

    88 

    89   // Accessors

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

    91   static MutableSpace* young_space() { return _young_space; }

    92 

    93   inline static PSPromotionManager* manager_array(int index);

    94   template <class T> inline void claim_or_forward_internal_depth(T* p);

    95 

    96   // On the task queues we push reference locations as well as

    97   // partially-scanned arrays (in the latter case, we push an oop to

    98   // the from-space image of the array and the length on the

    99   // from-space image indicates how many entries on the array we still

   100   // need to scan; this is basically how ParNew does partial array

   101   // scanning too). To be able to distinguish between reference

   102   // locations and partially-scanned array oops we simply mask the

   103   // latter oops with 0x01. The next three methods do the masking,

   104   // unmasking, and checking whether the oop is masked or not. Notice

   105   // that the signature of the mask and unmask methods looks a bit

   106   // strange, as they accept and return different types (oop and

   107   // oop*). This is because of the difference in types between what

   108   // the task queue holds (oop*) and oops to partially-scanned arrays

   109   // (oop). We do all the necessary casting in the mask / unmask

   110   // methods to avoid sprinkling the rest of the code with more casts.

   111 

   112   // These are added to the taskqueue so PS_CHUNKED_ARRAY_OOP_MASK (or any

   113   // future masks) can't conflict with COMPRESSED_OOP_MASK

   114 #define PS_CHUNKED_ARRAY_OOP_MASK  0x2

   115 

   116   bool is_oop_masked(StarTask p) {

   117     // If something is marked chunked it's always treated like wide oop*

   118     return (((intptr_t)(oop*)p) & PS_CHUNKED_ARRAY_OOP_MASK) ==

   119                                   PS_CHUNKED_ARRAY_OOP_MASK;

   120   }

   121 

   122   oop* mask_chunked_array_oop(oop obj) {

   123     assert(!is_oop_masked((oop*) obj), "invariant");

   124     oop* ret = (oop*) (cast_from_oop<uintptr_t>(obj) | PS_CHUNKED_ARRAY_OOP_MASK);

   125     assert(is_oop_masked(ret), "invariant");

   126     return ret;

   127   }

   128 

   129   oop unmask_chunked_array_oop(StarTask p) {

   130     assert(is_oop_masked(p), "invariant");

   131     assert(!p.is_narrow(), "chunked array oops cannot be narrow");

   132     oop *chunk = (oop*)p;  // cast p to oop (uses conversion operator)

   133     oop ret = oop((oop*)((uintptr_t)chunk & ~PS_CHUNKED_ARRAY_OOP_MASK));

   134     assert(!is_oop_masked((oop*) ret), "invariant");

   135     return ret;

   136   }

   137 

   138   template <class T> void  process_array_chunk_work(oop obj,

   139                                                     int start, int end);

   140   void process_array_chunk(oop old);

   141 

   142   template <class T> void push_depth(T* p);

   143 

   144   inline void promotion_trace_event(oop new_obj, oop old_obj, size_t obj_size,

   145                                     uint age, bool tenured,

   146                                     const PSPromotionLAB* lab);

   147 

   148  protected:

   149   static OopStarTaskQueueSet* stack_array_depth()   { return _stack_array_depth; }

   150  public:

   151   // Static

   152   static void initialize();

   153 

   154   static void pre_scavenge();

   155   static bool post_scavenge(YoungGCTracer& gc_tracer);

   156 

   157   static PSPromotionManager* gc_thread_promotion_manager(int index);

   158   static PSPromotionManager* vm_thread_promotion_manager();

   159 

   160   static bool steal_depth(int queue_num, int* seed, StarTask& t);

   161 

   162   PSPromotionManager();

   163 

   164   // Accessors

   165   OopStarTaskQueue* claimed_stack_depth() {

   166     return &_claimed_stack_depth;

   167   }

   168 

   169   bool young_gen_is_full()             { return _young_gen_is_full; }

   170 

   171   bool old_gen_is_full()               { return _old_gen_is_full; }

   172   void set_old_gen_is_full(bool state) { _old_gen_is_full = state; }

   173 

   174   // Promotion methods

   175   template<bool promote_immediately> oop copy_to_survivor_space(oop o);

   176   oop oop_promotion_failed(oop obj, markOop obj_mark);

   177 

   178   void reset();

   179 

   180   void flush_labs();

   181   void drain_stacks(bool totally_drain) {

   182     drain_stacks_depth(totally_drain);

   183   }

   184  public:

   185   void drain_stacks_cond_depth() {

   186     if (claimed_stack_depth()->size() > _target_stack_size) {

   187       drain_stacks_depth(false);

   188     }

   189   }

   190   void drain_stacks_depth(bool totally_drain);

   191 

   192   bool stacks_empty() {

   193     return claimed_stack_depth()->is_empty();

   194   }

   195 

   196   inline void process_popped_location_depth(StarTask p);

   197 

   198   static bool should_scavenge(oop* p, bool check_to_space = false);

   199   static bool should_scavenge(narrowOop* p, bool check_to_space = false);

   200 

   201   template <class T, bool promote_immediately>

   202   void copy_and_push_safe_barrier(T* p);

   203 

   204   template <class T> inline void claim_or_forward_depth(T* p);

   205 

   206   TASKQUEUE_STATS_ONLY(inline void record_steal(StarTask& p);)

   207 

   208   void push_contents(oop obj);

   209 };

   210 

   211 #endif // SHARE_VM_GC_PARALLEL_PSPROMOTIONMANAGER_HPP