1 /* 2 * Copyright (c) 1997, 2017, 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 #include "precompiled.hpp" 26 #include "gc/shared/blockOffsetTable.inline.hpp" 27 #include "gc/shared/cardTableRS.hpp" 28 #include "gc/shared/collectedHeap.inline.hpp" 29 #include "gc/shared/gcLocker.hpp" 30 #include "gc/shared/gcTimer.hpp" 31 #include "gc/shared/gcTrace.hpp" 32 #include "gc/shared/genCollectedHeap.hpp" 33 #include "gc/shared/genOopClosures.hpp" 34 #include "gc/shared/genOopClosures.inline.hpp" 35 #include "gc/shared/generation.hpp" 36 #include "gc/shared/generationSpec.hpp" 37 #include "gc/shared/space.inline.hpp" 38 #include "gc/shared/spaceDecorator.inline.hpp" 39 #include "logging/log.hpp" 40 #include "memory/allocation.inline.hpp" 41 #include "oops/oop.inline.hpp" 42 #include "runtime/java.hpp" 43 #include "utilities/copy.hpp" 44 #include "utilities/events.hpp" 45 46 Generation::Generation(ReservedSpace rs, size_t initial_size) : 47 _gc_manager(NULL), 48 _ref_processor(NULL) { 49 if (!_virtual_space.initialize(rs, initial_size)) { 50 vm_exit_during_initialization("Could not reserve enough space for " 51 "object heap"); 52 } 53 // Mangle all of the the initial generation. 54 if (ZapUnusedHeapArea) { 55 MemRegion mangle_region((HeapWord*)_virtual_space.low(), 56 (HeapWord*)_virtual_space.high()); 57 SpaceMangler::mangle_region(mangle_region); 58 } 59 _reserved = MemRegion((HeapWord*)_virtual_space.low_boundary(), 60 (HeapWord*)_virtual_space.high_boundary()); 61 } 62 63 size_t Generation::initial_size() { 64 GenCollectedHeap* gch = GenCollectedHeap::heap(); 65 if (gch->is_young_gen(this)) { 66 return gch->young_gen_spec()->init_size(); 67 } 68 return gch->old_gen_spec()->init_size(); 69 } 70 71 // This is for CMS. It returns stable monotonic used space size. 72 // Remove this when CMS is removed. 73 size_t Generation::used_stable() const { 74 return used(); 75 } 76 77 size_t Generation::max_capacity() const { 78 return reserved().byte_size(); 79 } 80 81 // By default we get a single threaded default reference processor; 82 // generations needing multi-threaded refs processing or discovery override this method. 83 void Generation::ref_processor_init() { 84 assert(_ref_processor == NULL, "a reference processor already exists"); 85 assert(!_reserved.is_empty(), "empty generation?"); 86 _span_based_discoverer.set_span(_reserved); 87 _ref_processor = new ReferenceProcessor(&_span_based_discoverer); // a vanilla reference processor 88 if (_ref_processor == NULL) { 89 vm_exit_during_initialization("Could not allocate ReferenceProcessor object"); 90 } 91 } 92 93 void Generation::print() const { print_on(tty); } 94 95 void Generation::print_on(outputStream* st) const { 96 st->print(" %-20s", name()); 97 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K", 98 capacity()/K, used()/K); 99 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")", 100 p2i(_virtual_space.low_boundary()), 101 p2i(_virtual_space.high()), 102 p2i(_virtual_space.high_boundary())); 103 } 104 105 void Generation::print_summary_info_on(outputStream* st) { 106 StatRecord* sr = stat_record(); 107 double time = sr->accumulated_time.seconds(); 108 st->print_cr("Accumulated %s generation GC time %3.7f secs, " 109 "%u GC's, avg GC time %3.7f", 110 GenCollectedHeap::heap()->is_young_gen(this) ? "young" : "old" , 111 time, 112 sr->invocations, 113 sr->invocations > 0 ? time / sr->invocations : 0.0); 114 } 115 116 // Utility iterator classes 117 118 class GenerationIsInReservedClosure : public SpaceClosure { 119 public: 120 const void* _p; 121 Space* sp; 122 virtual void do_space(Space* s) { 123 if (sp == NULL) { 124 if (s->is_in_reserved(_p)) sp = s; 125 } 126 } 127 GenerationIsInReservedClosure(const void* p) : _p(p), sp(NULL) {} 128 }; 129 130 class GenerationIsInClosure : public SpaceClosure { 131 public: 132 const void* _p; 133 Space* sp; 134 virtual void do_space(Space* s) { 135 if (sp == NULL) { 136 if (s->is_in(_p)) sp = s; 137 } 138 } 139 GenerationIsInClosure(const void* p) : _p(p), sp(NULL) {} 140 }; 141 142 bool Generation::is_in(const void* p) const { 143 GenerationIsInClosure blk(p); 144 ((Generation*)this)->space_iterate(&blk); 145 return blk.sp != NULL; 146 } 147 148 size_t Generation::max_contiguous_available() const { 149 // The largest number of contiguous free words in this or any higher generation. 150 size_t avail = contiguous_available(); 151 size_t old_avail = 0; 152 if (GenCollectedHeap::heap()->is_young_gen(this)) { 153 old_avail = GenCollectedHeap::heap()->old_gen()->contiguous_available(); 154 } 155 return MAX2(avail, old_avail); 156 } 157 158 bool Generation::promotion_attempt_is_safe(size_t max_promotion_in_bytes) const { 159 size_t available = max_contiguous_available(); 160 bool res = (available >= max_promotion_in_bytes); 161 log_trace(gc)("Generation: promo attempt is%s safe: available(" SIZE_FORMAT ") %s max_promo(" SIZE_FORMAT ")", 162 res? "":" not", available, res? ">=":"<", max_promotion_in_bytes); 163 return res; 164 } 165 166 // Ignores "ref" and calls allocate(). 167 oop Generation::promote(oop obj, size_t obj_size) { 168 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); 169 170 #ifndef PRODUCT 171 if (GenCollectedHeap::heap()->promotion_should_fail()) { 172 return NULL; 173 } 174 #endif // #ifndef PRODUCT 175 176 HeapWord* result = allocate(obj_size, false); 177 if (result != NULL) { 178 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size); 179 return oop(result); 180 } else { 181 GenCollectedHeap* gch = GenCollectedHeap::heap(); 182 return gch->handle_failed_promotion(this, obj, obj_size); 183 } 184 } 185 186 oop Generation::par_promote(int thread_num, 187 oop obj, markWord m, size_t word_sz) { 188 // Could do a bad general impl here that gets a lock. But no. 189 ShouldNotCallThis(); 190 return NULL; 191 } 192 193 Space* Generation::space_containing(const void* p) const { 194 GenerationIsInReservedClosure blk(p); 195 // Cast away const 196 ((Generation*)this)->space_iterate(&blk); 197 return blk.sp; 198 } 199 200 // Some of these are mediocre general implementations. Should be 201 // overridden to get better performance. 202 203 class GenerationBlockStartClosure : public SpaceClosure { 204 public: 205 const void* _p; 206 HeapWord* _start; 207 virtual void do_space(Space* s) { 208 if (_start == NULL && s->is_in_reserved(_p)) { 209 _start = s->block_start(_p); 210 } 211 } 212 GenerationBlockStartClosure(const void* p) { _p = p; _start = NULL; } 213 }; 214 215 HeapWord* Generation::block_start(const void* p) const { 216 GenerationBlockStartClosure blk(p); 217 // Cast away const 218 ((Generation*)this)->space_iterate(&blk); 219 return blk._start; 220 } 221 222 class GenerationBlockSizeClosure : public SpaceClosure { 223 public: 224 const HeapWord* _p; 225 size_t size; 226 virtual void do_space(Space* s) { 227 if (size == 0 && s->is_in_reserved(_p)) { 228 size = s->block_size(_p); 229 } 230 } 231 GenerationBlockSizeClosure(const HeapWord* p) { _p = p; size = 0; } 232 }; 233 234 size_t Generation::block_size(const HeapWord* p) const { 235 GenerationBlockSizeClosure blk(p); 236 // Cast away const 237 ((Generation*)this)->space_iterate(&blk); 238 assert(blk.size > 0, "seems reasonable"); 239 return blk.size; 240 } 241 242 class GenerationBlockIsObjClosure : public SpaceClosure { 243 public: 244 const HeapWord* _p; 245 bool is_obj; 246 virtual void do_space(Space* s) { 247 if (!is_obj && s->is_in_reserved(_p)) { 248 is_obj |= s->block_is_obj(_p); 249 } 250 } 251 GenerationBlockIsObjClosure(const HeapWord* p) { _p = p; is_obj = false; } 252 }; 253 254 bool Generation::block_is_obj(const HeapWord* p) const { 255 GenerationBlockIsObjClosure blk(p); 256 // Cast away const 257 ((Generation*)this)->space_iterate(&blk); 258 return blk.is_obj; 259 } 260 261 class GenerationOopIterateClosure : public SpaceClosure { 262 public: 263 OopIterateClosure* _cl; 264 virtual void do_space(Space* s) { 265 s->oop_iterate(_cl); 266 } 267 GenerationOopIterateClosure(OopIterateClosure* cl) : 268 _cl(cl) {} 269 }; 270 271 void Generation::oop_iterate(OopIterateClosure* cl) { 272 GenerationOopIterateClosure blk(cl); 273 space_iterate(&blk); 274 } 275 276 void Generation::younger_refs_in_space_iterate(Space* sp, 277 OopsInGenClosure* cl, 278 uint n_threads) { 279 CardTableRS* rs = GenCollectedHeap::heap()->rem_set(); 280 rs->younger_refs_in_space_iterate(sp, cl, n_threads); 281 } 282 283 class GenerationObjIterateClosure : public SpaceClosure { 284 private: 285 ObjectClosure* _cl; 286 public: 287 virtual void do_space(Space* s) { 288 s->object_iterate(_cl); 289 } 290 GenerationObjIterateClosure(ObjectClosure* cl) : _cl(cl) {} 291 }; 292 293 void Generation::object_iterate(ObjectClosure* cl) { 294 GenerationObjIterateClosure blk(cl); 295 space_iterate(&blk); 296 } 297 298 class GenerationSafeObjIterateClosure : public SpaceClosure { 299 private: 300 ObjectClosure* _cl; 301 public: 302 virtual void do_space(Space* s) { 303 s->safe_object_iterate(_cl); 304 } 305 GenerationSafeObjIterateClosure(ObjectClosure* cl) : _cl(cl) {} 306 }; 307 308 void Generation::safe_object_iterate(ObjectClosure* cl) { 309 GenerationSafeObjIterateClosure blk(cl); 310 space_iterate(&blk); 311 } 312 313 #if INCLUDE_SERIALGC 314 315 void Generation::prepare_for_compaction(CompactPoint* cp) { 316 // Generic implementation, can be specialized 317 CompactibleSpace* space = first_compaction_space(); 318 while (space != NULL) { 319 space->prepare_for_compaction(cp); 320 space = space->next_compaction_space(); 321 } 322 } 323 324 class AdjustPointersClosure: public SpaceClosure { 325 public: 326 void do_space(Space* sp) { 327 sp->adjust_pointers(); 328 } 329 }; 330 331 void Generation::adjust_pointers() { 332 // Note that this is done over all spaces, not just the compactible 333 // ones. 334 AdjustPointersClosure blk; 335 space_iterate(&blk, true); 336 } 337 338 void Generation::compact() { 339 CompactibleSpace* sp = first_compaction_space(); 340 while (sp != NULL) { 341 sp->compact(); 342 sp = sp->next_compaction_space(); 343 } 344 } 345 346 #endif // INCLUDE_SERIALGC