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