1 /* 2 * Copyright (c) 2001, 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_SERIAL_DEFNEWGENERATION_HPP 26 #define SHARE_VM_GC_SERIAL_DEFNEWGENERATION_HPP 27 28 #include "gc/serial/cSpaceCounters.hpp" 29 #include "gc/shared/ageTable.hpp" 30 #include "gc/shared/copyFailedInfo.hpp" 31 #include "gc/shared/generation.hpp" 32 #include "gc/shared/generationCounters.hpp" 33 #include "gc/shared/preservedMarks.hpp" 34 #include "utilities/stack.hpp" 35 36 class ContiguousSpace; 37 class ScanClosure; 38 class STWGCTimer; 39 class CSpaceCounters; 40 class ScanWeakRefClosure; 41 42 // DefNewGeneration is a young generation containing eden, from- and 43 // to-space. 44 45 class DefNewGeneration: public Generation { 46 friend class VMStructs; 47 48 protected: 49 Generation* _old_gen; 50 uint _tenuring_threshold; // Tenuring threshold for next collection. 51 AgeTable _age_table; 52 // Size of object to pretenure in words; command line provides bytes 53 size_t _pretenure_size_threshold_words; 54 55 AgeTable* age_table() { return &_age_table; } 56 57 // Initialize state to optimistically assume no promotion failure will 58 // happen. 59 void init_assuming_no_promotion_failure(); 60 // True iff a promotion has failed in the current collection. 61 bool _promotion_failed; 62 bool promotion_failed() { return _promotion_failed; } 63 PromotionFailedInfo _promotion_failed_info; 64 65 // Handling promotion failure. A young generation collection 66 // can fail if a live object cannot be copied out of its 67 // location in eden or from-space during the collection. If 68 // a collection fails, the young generation is left in a 69 // consistent state such that it can be collected by a 70 // full collection. 71 // Before the collection 72 // Objects are in eden or from-space 73 // All roots into the young generation point into eden or from-space. 74 // 75 // After a failed collection 76 // Objects may be in eden, from-space, or to-space 77 // An object A in eden or from-space may have a copy B 78 // in to-space. If B exists, all roots that once pointed 79 // to A must now point to B. 80 // All objects in the young generation are unmarked. 81 // Eden, from-space, and to-space will all be collected by 82 // the full collection. 83 void handle_promotion_failure(oop); 84 85 // In the absence of promotion failure, we wouldn't look at "from-space" 86 // objects after a young-gen collection. When promotion fails, however, 87 // the subsequent full collection will look at from-space objects: 88 // therefore we must remove their forwarding pointers. 89 void remove_forwarding_pointers(); 90 91 // Preserved marks 92 PreservedMarksSet _preserved_marks_set; 93 94 // Promotion failure handling 95 ExtendedOopClosure *_promo_failure_scan_stack_closure; 96 void set_promo_failure_scan_stack_closure(ExtendedOopClosure *scan_stack_closure) { 97 _promo_failure_scan_stack_closure = scan_stack_closure; 98 } 99 100 Stack<oop, mtGC> _promo_failure_scan_stack; 101 void drain_promo_failure_scan_stack(void); 102 bool _promo_failure_drain_in_progress; 103 104 // Performance Counters 105 GenerationCounters* _gen_counters; 106 CSpaceCounters* _eden_counters; 107 CSpaceCounters* _from_counters; 108 CSpaceCounters* _to_counters; 109 110 // sizing information 111 size_t _max_eden_size; 112 size_t _max_survivor_size; 113 114 // Allocation support 115 bool _should_allocate_from_space; 116 bool should_allocate_from_space() const { 117 return _should_allocate_from_space; 118 } 119 void clear_should_allocate_from_space() { 120 _should_allocate_from_space = false; 121 } 122 void set_should_allocate_from_space() { 123 _should_allocate_from_space = true; 124 } 125 126 // Tenuring 127 void adjust_desired_tenuring_threshold(); 128 129 // Spaces 130 ContiguousSpace* _eden_space; 131 ContiguousSpace* _from_space; 132 ContiguousSpace* _to_space; 133 134 STWGCTimer* _gc_timer; 135 136 enum SomeProtectedConstants { 137 // Generations are GenGrain-aligned and have size that are multiples of 138 // GenGrain. 139 MinFreeScratchWords = 100 140 }; 141 142 // Return the size of a survivor space if this generation were of size 143 // gen_size. 144 size_t compute_survivor_size(size_t gen_size, size_t alignment) const { 145 size_t n = gen_size / (SurvivorRatio + 2); 146 return n > alignment ? align_size_down(n, alignment) : alignment; 147 } 148 149 public: // was "protected" but caused compile error on win32 150 class IsAliveClosure: public BoolObjectClosure { 151 Generation* _young_gen; 152 public: 153 IsAliveClosure(Generation* young_gen); 154 bool do_object_b(oop p); 155 }; 156 157 class KeepAliveClosure: public OopClosure { 158 protected: 159 ScanWeakRefClosure* _cl; 160 CardTableRS* _rs; 161 template <class T> void do_oop_work(T* p); 162 public: 163 KeepAliveClosure(ScanWeakRefClosure* cl); 164 virtual void do_oop(oop* p); 165 virtual void do_oop(narrowOop* p); 166 }; 167 168 class FastKeepAliveClosure: public KeepAliveClosure { 169 protected: 170 HeapWord* _boundary; 171 template <class T> void do_oop_work(T* p); 172 public: 173 FastKeepAliveClosure(DefNewGeneration* g, ScanWeakRefClosure* cl); 174 virtual void do_oop(oop* p); 175 virtual void do_oop(narrowOop* p); 176 }; 177 178 class EvacuateFollowersClosure: public VoidClosure { 179 GenCollectedHeap* _gch; 180 ScanClosure* _scan_cur_or_nonheap; 181 ScanClosure* _scan_older; 182 public: 183 EvacuateFollowersClosure(GenCollectedHeap* gch, 184 ScanClosure* cur, ScanClosure* older); 185 void do_void(); 186 }; 187 188 class FastEvacuateFollowersClosure: public VoidClosure { 189 GenCollectedHeap* _gch; 190 DefNewGeneration* _young_gen; 191 FastScanClosure* _scan_cur_or_nonheap; 192 FastScanClosure* _scan_older; 193 public: 194 FastEvacuateFollowersClosure(GenCollectedHeap* gch, 195 FastScanClosure* cur, 196 FastScanClosure* older); 197 void do_void(); 198 }; 199 200 public: 201 DefNewGeneration(ReservedSpace rs, size_t initial_byte_size, 202 const char* policy="Copy"); 203 204 virtual void ref_processor_init(); 205 206 virtual Generation::Name kind() { return Generation::DefNew; } 207 208 // Accessing spaces 209 ContiguousSpace* eden() const { return _eden_space; } 210 ContiguousSpace* from() const { return _from_space; } 211 ContiguousSpace* to() const { return _to_space; } 212 213 virtual CompactibleSpace* first_compaction_space() const; 214 215 // Space enquiries 216 size_t capacity() const; 217 size_t used() const; 218 size_t free() const; 219 size_t max_capacity() const; 220 size_t capacity_before_gc() const; 221 size_t unsafe_max_alloc_nogc() const; 222 size_t contiguous_available() const; 223 224 size_t max_eden_size() const { return _max_eden_size; } 225 size_t max_survivor_size() const { return _max_survivor_size; } 226 227 bool supports_inline_contig_alloc() const { return true; } 228 HeapWord** top_addr() const; 229 HeapWord** end_addr() const; 230 231 // Thread-local allocation buffers 232 bool supports_tlab_allocation() const { return true; } 233 size_t tlab_capacity() const; 234 size_t tlab_used() const; 235 size_t unsafe_max_tlab_alloc() const; 236 237 // Grow the generation by the specified number of bytes. 238 // The size of bytes is assumed to be properly aligned. 239 // Return true if the expansion was successful. 240 bool expand(size_t bytes); 241 242 // DefNewGeneration cannot currently expand except at 243 // a GC. 244 virtual bool is_maximal_no_gc() const { return true; } 245 246 // Iteration 247 void object_iterate(ObjectClosure* blk); 248 249 void younger_refs_iterate(OopsInGenClosure* cl, uint n_threads); 250 251 void space_iterate(SpaceClosure* blk, bool usedOnly = false); 252 253 // Allocation support 254 virtual bool should_allocate(size_t word_size, bool is_tlab) { 255 assert(UseTLAB || !is_tlab, "Should not allocate tlab"); 256 257 size_t overflow_limit = (size_t)1 << (BitsPerSize_t - LogHeapWordSize); 258 259 const bool non_zero = word_size > 0; 260 const bool overflows = word_size >= overflow_limit; 261 const bool check_too_big = _pretenure_size_threshold_words > 0; 262 const bool not_too_big = word_size < _pretenure_size_threshold_words; 263 const bool size_ok = is_tlab || !check_too_big || not_too_big; 264 265 bool result = !overflows && 266 non_zero && 267 size_ok; 268 269 return result; 270 } 271 272 HeapWord* allocate(size_t word_size, bool is_tlab); 273 HeapWord* allocate_from_space(size_t word_size); 274 275 HeapWord* par_allocate(size_t word_size, bool is_tlab); 276 277 virtual void gc_epilogue(bool full); 278 279 // Save the tops for eden, from, and to 280 virtual void record_spaces_top(); 281 282 // Accessing marks 283 void save_marks(); 284 void reset_saved_marks(); 285 bool no_allocs_since_save_marks(); 286 287 // Need to declare the full complement of closures, whether we'll 288 // override them or not, or get message from the compiler: 289 // oop_since_save_marks_iterate_nv hides virtual function... 290 #define DefNew_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ 291 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl); 292 293 ALL_SINCE_SAVE_MARKS_CLOSURES(DefNew_SINCE_SAVE_MARKS_DECL) 294 295 #undef DefNew_SINCE_SAVE_MARKS_DECL 296 297 // For non-youngest collection, the DefNewGeneration can contribute 298 // "to-space". 299 virtual void contribute_scratch(ScratchBlock*& list, Generation* requestor, 300 size_t max_alloc_words); 301 302 // Reset for contribution of "to-space". 303 virtual void reset_scratch(); 304 305 // GC support 306 virtual void compute_new_size(); 307 308 // Returns true if the collection is likely to be safely 309 // completed. Even if this method returns true, a collection 310 // may not be guaranteed to succeed, and the system should be 311 // able to safely unwind and recover from that failure, albeit 312 // at some additional cost. Override superclass's implementation. 313 virtual bool collection_attempt_is_safe(); 314 315 virtual void collect(bool full, 316 bool clear_all_soft_refs, 317 size_t size, 318 bool is_tlab); 319 HeapWord* expand_and_allocate(size_t size, 320 bool is_tlab, 321 bool parallel = false); 322 323 oop copy_to_survivor_space(oop old); 324 uint tenuring_threshold() { return _tenuring_threshold; } 325 326 // Performance Counter support 327 void update_counters(); 328 329 // Printing 330 virtual const char* name() const; 331 virtual const char* short_name() const { return "DefNew"; } 332 333 void print_on(outputStream* st) const; 334 335 void verify(); 336 337 bool promo_failure_scan_is_complete() const { 338 return _promo_failure_scan_stack.is_empty(); 339 } 340 341 protected: 342 // If clear_space is true, clear the survivor spaces. Eden is 343 // cleared if the minimum size of eden is 0. If mangle_space 344 // is true, also mangle the space in debug mode. 345 void compute_space_boundaries(uintx minimum_eden_size, 346 bool clear_space, 347 bool mangle_space); 348 349 // Return adjusted new size for NewSizeThreadIncrease. 350 // If any overflow happens, revert to previous new size. 351 size_t adjust_for_thread_increase(size_t new_size_candidate, 352 size_t new_size_before, 353 size_t alignment) const; 354 355 356 // Scavenge support 357 void swap_spaces(); 358 }; 359 360 #endif // SHARE_VM_GC_SERIAL_DEFNEWGENERATION_HPP