1 /*
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   3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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   6  * under the terms of the GNU General Public License version 2 only, as
   7  * published by the Free Software Foundation.
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  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).
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  24 
  25 #ifndef SHARE_GC_PARALLEL_PSPROMOTIONMANAGER_HPP
  26 #define SHARE_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/preservedMarks.hpp"
  32 #include "gc/shared/taskqueue.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 {
  53   friend class PSScavenge;
  54   friend class ScavengeRootsTask;
  55   friend class PSRefProcTaskExecutor;
  56   friend class PSRefProcTask;
  57 
  58  private:
  59   static PaddedEnd<PSPromotionManager>* _manager_array;
  60   static OopStarTaskQueueSet*           _stack_array_depth;
  61   static PreservedMarksSet*             _preserved_marks_set;
  62   static PSOldGen*                      _old_gen;
  63   static MutableSpace*                  _young_space;
  64 
  65 #if TASKQUEUE_STATS
  66   size_t                              _masked_pushes;
  67   size_t                              _masked_steals;
  68   size_t                              _arrays_chunked;
  69   size_t                              _array_chunks_processed;
  70 
  71   void print_local_stats(outputStream* const out, uint i) const;
  72   static void print_taskqueue_stats();
  73 
  74   void reset_stats();
  75 #endif // TASKQUEUE_STATS
  76 
  77   PSYoungPromotionLAB                 _young_lab;
  78   PSOldPromotionLAB                   _old_lab;
  79   bool                                _young_gen_is_full;
  80   bool                                _old_gen_is_full;
  81 
  82   OopStarTaskQueue                    _claimed_stack_depth;
  83   OverflowTaskQueue<oop, mtGC>        _claimed_stack_breadth;
  84 
  85   bool                                _totally_drain;
  86   uint                                _target_stack_size;
  87 
  88   uint                                _array_chunk_size;
  89   uint                                _min_array_size_for_chunking;
  90 
  91   PreservedMarks*                     _preserved_marks;
  92   PromotionFailedInfo                 _promotion_failed_info;
  93 
  94   // Accessors
  95   static PSOldGen* old_gen()         { return _old_gen; }
  96   static MutableSpace* young_space() { return _young_space; }
  97 
  98   inline static PSPromotionManager* manager_array(uint index);
  99   template <class T> inline void claim_or_forward_internal_depth(T* p);
 100 
 101   // On the task queues we push reference locations as well as
 102   // partially-scanned arrays (in the latter case, we push an oop to
 103   // the from-space image of the array and the length on the
 104   // from-space image indicates how many entries on the array we still
 105   // need to scan; this is basically how ParNew does partial array
 106   // scanning too). To be able to distinguish between reference
 107   // locations and partially-scanned array oops we simply mask the
 108   // latter oops with 0x01. The next three methods do the masking,
 109   // unmasking, and checking whether the oop is masked or not. Notice
 110   // that the signature of the mask and unmask methods looks a bit
 111   // strange, as they accept and return different types (oop and
 112   // oop*). This is because of the difference in types between what
 113   // the task queue holds (oop*) and oops to partially-scanned arrays
 114   // (oop). We do all the necessary casting in the mask / unmask
 115   // methods to avoid sprinkling the rest of the code with more casts.
 116 
 117   // These are added to the taskqueue so PS_CHUNKED_ARRAY_OOP_MASK (or any
 118   // future masks) can't conflict with COMPRESSED_OOP_MASK
 119 #define PS_CHUNKED_ARRAY_OOP_MASK  0x2
 120 
 121   bool is_oop_masked(StarTask p) {
 122     // If something is marked chunked it's always treated like wide oop*
 123     return (((intptr_t)(oop*)p) & PS_CHUNKED_ARRAY_OOP_MASK) ==
 124                                   PS_CHUNKED_ARRAY_OOP_MASK;
 125   }
 126 
 127   oop* mask_chunked_array_oop(oop obj) {
 128     assert(!is_oop_masked((oop*) obj), "invariant");
 129     oop* ret = (oop*) (cast_from_oop<uintptr_t>(obj) | PS_CHUNKED_ARRAY_OOP_MASK);
 130     assert(is_oop_masked(ret), "invariant");
 131     return ret;
 132   }
 133 
 134   oop unmask_chunked_array_oop(StarTask p) {
 135     assert(is_oop_masked(p), "invariant");
 136     assert(!p.is_narrow(), "chunked array oops cannot be narrow");
 137     oop *chunk = (oop*)p;  // cast p to oop (uses conversion operator)
 138     oop ret = oop((oop*)((uintptr_t)chunk & ~PS_CHUNKED_ARRAY_OOP_MASK));
 139     assert(!is_oop_masked((oop*) ret), "invariant");
 140     return ret;
 141   }
 142 
 143   template <class T> void  process_array_chunk_work(oop obj,
 144                                                     int start, int end);
 145   void process_array_chunk(oop old);
 146 
 147   template <class T> void push_depth(T* p);
 148 
 149   inline void promotion_trace_event(oop new_obj, oop old_obj, size_t obj_size,
 150                                     uint age, bool tenured,
 151                                     const PSPromotionLAB* lab);
 152 
 153  protected:
 154   static OopStarTaskQueueSet* stack_array_depth()   { return _stack_array_depth; }
 155  public:
 156   // Static
 157   static void initialize();
 158 
 159   static void pre_scavenge();
 160   static bool post_scavenge(YoungGCTracer& gc_tracer);
 161 
 162   static PSPromotionManager* gc_thread_promotion_manager(uint index);
 163   static PSPromotionManager* vm_thread_promotion_manager();
 164 
 165   static bool steal_depth(int queue_num, StarTask& t);
 166 
 167   PSPromotionManager();
 168 
 169   // Accessors
 170   OopStarTaskQueue* claimed_stack_depth() {
 171     return &_claimed_stack_depth;
 172   }
 173 
 174   bool young_gen_is_full()             { return _young_gen_is_full; }
 175 
 176   bool old_gen_is_full()               { return _old_gen_is_full; }
 177   void set_old_gen_is_full(bool state) { _old_gen_is_full = state; }
 178 
 179   // Promotion methods
 180   template<bool promote_immediately> oop copy_to_survivor_space(oop o);
 181   oop oop_promotion_failed(oop obj, markWord obj_mark);
 182 
 183   void reset();
 184   void register_preserved_marks(PreservedMarks* preserved_marks);
 185   static void restore_preserved_marks();
 186 
 187   void flush_labs();
 188   void drain_stacks(bool totally_drain) {
 189     drain_stacks_depth(totally_drain);
 190   }
 191  public:
 192   void drain_stacks_cond_depth() {
 193     if (claimed_stack_depth()->size() > _target_stack_size) {
 194       drain_stacks_depth(false);
 195     }
 196   }
 197   void drain_stacks_depth(bool totally_drain);
 198 
 199   bool stacks_empty() {
 200     return claimed_stack_depth()->is_empty();
 201   }
 202 
 203   inline void process_popped_location_depth(StarTask p);
 204 
 205   static bool should_scavenge(oop* p, bool check_to_space = false);
 206   static bool should_scavenge(narrowOop* p, bool check_to_space = false);
 207 
 208   template <class T, bool promote_immediately>
 209   void copy_and_push_safe_barrier(T* p);
 210 
 211   template <class T> inline void claim_or_forward_depth(T* p);
 212 
 213   TASKQUEUE_STATS_ONLY(inline void record_steal(StarTask& p);)
 214 
 215   void push_contents(oop obj);
 216 };
 217 
 218 #endif // SHARE_GC_PARALLEL_PSPROMOTIONMANAGER_HPP