1 /* 2 * Copyright (c) 2002, 2010, 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 // 26 // psPromotionManager is used by a single thread to manage object survival 27 // during a scavenge. The promotion manager contains thread local data only. 28 // 29 // NOTE! Be carefull when allocating the stacks on cheap. If you are going 30 // to use a promotion manager in more than one thread, the stacks MUST be 31 // on cheap. This can lead to memory leaks, though, as they are not auto 32 // deallocated. 33 // 34 // FIX ME FIX ME Add a destructor, and don't rely on the user to drain/flush/deallocate! 35 // 36 37 // Move to some global location 38 #define HAS_BEEN_MOVED 0x1501d01d 39 // End move to some global location 40 41 class MutableSpace; 42 class PSOldGen; 43 class ParCompactionManager; 44 45 class PSPromotionManager : public CHeapObj { 46 friend class PSScavenge; 47 friend class PSRefProcTaskExecutor; 48 private: 49 static PSPromotionManager** _manager_array; 50 static OopStarTaskQueueSet* _stack_array_depth; 51 static PSOldGen* _old_gen; 52 static MutableSpace* _young_space; 53 54 #if TASKQUEUE_STATS 55 size_t _masked_pushes; 56 size_t _masked_steals; 57 size_t _arrays_chunked; 58 size_t _array_chunks_processed; 59 60 void print_taskqueue_stats(uint i) const; 61 void print_local_stats(uint i) const; 62 static void print_stats(); 63 64 void reset_stats(); 65 #endif // TASKQUEUE_STATS 66 67 PSYoungPromotionLAB _young_lab; 68 PSOldPromotionLAB _old_lab; 69 bool _young_gen_is_full; 70 bool _old_gen_is_full; 71 72 OopStarTaskQueue _claimed_stack_depth; 73 OverflowTaskQueue<oop> _claimed_stack_breadth; 74 75 bool _totally_drain; 76 uint _target_stack_size; 77 78 uint _array_chunk_size; 79 uint _min_array_size_for_chunking; 80 81 // Accessors 82 static PSOldGen* old_gen() { return _old_gen; } 83 static MutableSpace* young_space() { return _young_space; } 84 85 inline static PSPromotionManager* manager_array(int index); 86 template <class T> inline void claim_or_forward_internal_depth(T* p); 87 88 // On the task queues we push reference locations as well as 89 // partially-scanned arrays (in the latter case, we push an oop to 90 // the from-space image of the array and the length on the 91 // from-space image indicates how many entries on the array we still 92 // need to scan; this is basically how ParNew does partial array 93 // scanning too). To be able to distinguish between reference 94 // locations and partially-scanned array oops we simply mask the 95 // latter oops with 0x01. The next three methods do the masking, 96 // unmasking, and checking whether the oop is masked or not. Notice 97 // that the signature of the mask and unmask methods looks a bit 98 // strange, as they accept and return different types (oop and 99 // oop*). This is because of the difference in types between what 100 // the task queue holds (oop*) and oops to partially-scanned arrays 101 // (oop). We do all the necessary casting in the mask / unmask 102 // methods to avoid sprinkling the rest of the code with more casts. 103 104 // These are added to the taskqueue so PS_CHUNKED_ARRAY_OOP_MASK (or any 105 // future masks) can't conflict with COMPRESSED_OOP_MASK 106 #define PS_CHUNKED_ARRAY_OOP_MASK 0x2 107 108 bool is_oop_masked(StarTask p) { 109 // If something is marked chunked it's always treated like wide oop* 110 return (((intptr_t)(oop*)p) & PS_CHUNKED_ARRAY_OOP_MASK) == 111 PS_CHUNKED_ARRAY_OOP_MASK; 112 } 113 114 oop* mask_chunked_array_oop(oop obj) { 115 assert(!is_oop_masked((oop*) obj), "invariant"); 116 oop* ret = (oop*) ((uintptr_t)obj | PS_CHUNKED_ARRAY_OOP_MASK); 117 assert(is_oop_masked(ret), "invariant"); 118 return ret; 119 } 120 121 oop unmask_chunked_array_oop(StarTask p) { 122 assert(is_oop_masked(p), "invariant"); 123 assert(!p.is_narrow(), "chunked array oops cannot be narrow"); 124 oop *chunk = (oop*)p; // cast p to oop (uses conversion operator) 125 oop ret = oop((oop*)((uintptr_t)chunk & ~PS_CHUNKED_ARRAY_OOP_MASK)); 126 assert(!is_oop_masked((oop*) ret), "invariant"); 127 return ret; 128 } 129 130 template <class T> void process_array_chunk_work(oop obj, 131 int start, int end); 132 void process_array_chunk(oop old); 133 134 template <class T> void push_depth(T* p) { 135 claimed_stack_depth()->push(p); 136 } 137 138 protected: 139 static OopStarTaskQueueSet* stack_array_depth() { return _stack_array_depth; } 140 public: 141 // Static 142 static void initialize(); 143 144 static void pre_scavenge(); 145 static void post_scavenge(); 146 147 static PSPromotionManager* gc_thread_promotion_manager(int index); 148 static PSPromotionManager* vm_thread_promotion_manager(); 149 150 static bool steal_depth(int queue_num, int* seed, StarTask& t) { 151 return stack_array_depth()->steal(queue_num, seed, t); 152 } 153 154 PSPromotionManager(); 155 156 // Accessors 157 OopStarTaskQueue* claimed_stack_depth() { 158 return &_claimed_stack_depth; 159 } 160 161 bool young_gen_is_full() { return _young_gen_is_full; } 162 163 bool old_gen_is_full() { return _old_gen_is_full; } 164 void set_old_gen_is_full(bool state) { _old_gen_is_full = state; } 165 166 // Promotion methods 167 oop copy_to_survivor_space(oop o); 168 oop oop_promotion_failed(oop obj, markOop obj_mark); 169 170 void reset(); 171 172 void flush_labs(); 173 void drain_stacks(bool totally_drain) { 174 drain_stacks_depth(totally_drain); 175 } 176 public: 177 void drain_stacks_cond_depth() { 178 if (claimed_stack_depth()->size() > _target_stack_size) { 179 drain_stacks_depth(false); 180 } 181 } 182 void drain_stacks_depth(bool totally_drain); 183 184 bool stacks_empty() { 185 return claimed_stack_depth()->is_empty(); 186 } 187 188 inline void process_popped_location_depth(StarTask p); 189 190 template <class T> inline void claim_or_forward_depth(T* p); 191 192 TASKQUEUE_STATS_ONLY(inline void record_steal(StarTask& p);) 193 };