1 /* 2 * Copyright (c) 2001, 2019, 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/parallel/objectStartArray.inline.hpp" 27 #include "gc/parallel/parallelArguments.hpp" 28 #include "gc/parallel/parallelScavengeHeap.hpp" 29 #include "gc/parallel/psAdaptiveSizePolicy.hpp" 30 #include "gc/parallel/psCardTable.hpp" 31 #include "gc/parallel/psFileBackedVirtualspace.hpp" 32 #include "gc/parallel/psMarkSweepDecorator.hpp" 33 #include "gc/parallel/psOldGen.hpp" 34 #include "gc/shared/cardTableBarrierSet.hpp" 35 #include "gc/shared/gcLocker.hpp" 36 #include "gc/shared/spaceDecorator.inline.hpp" 37 #include "logging/log.hpp" 38 #include "oops/oop.inline.hpp" 39 #include "runtime/java.hpp" 40 #include "utilities/align.hpp" 41 42 inline const char* PSOldGen::select_name() { 43 return UseParallelOldGC ? "ParOldGen" : "PSOldGen"; 44 } 45 46 PSOldGen::PSOldGen(ReservedSpace rs, size_t alignment, 47 size_t initial_size, size_t min_size, size_t max_size, 48 const char* perf_data_name, int level): 49 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size), 50 _max_gen_size(max_size) 51 { 52 initialize(rs, alignment, perf_data_name, level); 53 } 54 55 PSOldGen::PSOldGen(size_t initial_size, 56 size_t min_size, size_t max_size, 57 const char* perf_data_name, int level): 58 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size), 59 _max_gen_size(max_size) 60 {} 61 62 void PSOldGen::initialize(ReservedSpace rs, size_t alignment, 63 const char* perf_data_name, int level) { 64 initialize_virtual_space(rs, alignment); 65 initialize_work(perf_data_name, level); 66 67 // The old gen can grow to gen_size_limit(). _reserve reflects only 68 // the current maximum that can be committed. 69 assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check"); 70 71 initialize_performance_counters(perf_data_name, level); 72 } 73 74 void PSOldGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) { 75 76 if(ParallelArguments::is_heterogeneous_heap()) { 77 _virtual_space = new PSFileBackedVirtualSpace(rs, alignment, AllocateOldGenAt); 78 if (!(static_cast <PSFileBackedVirtualSpace*>(_virtual_space))->initialize()) { 79 vm_exit_during_initialization("Could not map space for PSOldGen at given AllocateOldGenAt path"); 80 } 81 } else { 82 _virtual_space = new PSVirtualSpace(rs, alignment); 83 } 84 if (!_virtual_space->expand_by(_init_gen_size)) { 85 vm_exit_during_initialization("Could not reserve enough space for " 86 "object heap"); 87 } 88 } 89 90 void PSOldGen::initialize_work(const char* perf_data_name, int level) { 91 // 92 // Basic memory initialization 93 // 94 95 MemRegion limit_reserved((HeapWord*)virtual_space()->low_boundary(), 96 heap_word_size(_max_gen_size)); 97 assert(limit_reserved.byte_size() == _max_gen_size, 98 "word vs bytes confusion"); 99 // 100 // Object start stuff 101 // 102 103 start_array()->initialize(limit_reserved); 104 105 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(), 106 (HeapWord*)virtual_space()->high_boundary()); 107 108 // 109 // Card table stuff 110 // 111 112 MemRegion cmr((HeapWord*)virtual_space()->low(), 113 (HeapWord*)virtual_space()->high()); 114 if (ZapUnusedHeapArea) { 115 // Mangle newly committed space immediately rather than 116 // waiting for the initialization of the space even though 117 // mangling is related to spaces. Doing it here eliminates 118 // the need to carry along information that a complete mangling 119 // (bottom to end) needs to be done. 120 SpaceMangler::mangle_region(cmr); 121 } 122 123 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 124 PSCardTable* ct = heap->card_table(); 125 ct->resize_covered_region(cmr); 126 127 // Verify that the start and end of this generation is the start of a card. 128 // If this wasn't true, a single card could span more than one generation, 129 // which would cause problems when we commit/uncommit memory, and when we 130 // clear and dirty cards. 131 guarantee(ct->is_card_aligned(_reserved.start()), "generation must be card aligned"); 132 if (_reserved.end() != heap->reserved_region().end()) { 133 // Don't check at the very end of the heap as we'll assert that we're probing off 134 // the end if we try. 135 guarantee(ct->is_card_aligned(_reserved.end()), "generation must be card aligned"); 136 } 137 138 // 139 // ObjectSpace stuff 140 // 141 142 _object_space = new MutableSpace(virtual_space()->alignment()); 143 144 if (_object_space == NULL) 145 vm_exit_during_initialization("Could not allocate an old gen space"); 146 147 object_space()->initialize(cmr, 148 SpaceDecorator::Clear, 149 SpaceDecorator::Mangle); 150 151 #if INCLUDE_SERIALGC 152 _object_mark_sweep = new PSMarkSweepDecorator(_object_space, start_array(), MarkSweepDeadRatio); 153 154 if (_object_mark_sweep == NULL) { 155 vm_exit_during_initialization("Could not complete allocation of old generation"); 156 } 157 #endif // INCLUDE_SERIALGC 158 159 // Update the start_array 160 start_array()->set_covered_region(cmr); 161 } 162 163 void PSOldGen::initialize_performance_counters(const char* perf_data_name, int level) { 164 // Generation Counters, generation 'level', 1 subspace 165 _gen_counters = new PSGenerationCounters(perf_data_name, level, 1, _min_gen_size, 166 _max_gen_size, virtual_space()); 167 _space_counters = new SpaceCounters(perf_data_name, 0, 168 virtual_space()->reserved_size(), 169 _object_space, _gen_counters); 170 } 171 172 // Assume that the generation has been allocated if its 173 // reserved size is not 0. 174 bool PSOldGen::is_allocated() { 175 return virtual_space()->reserved_size() != 0; 176 } 177 178 #if INCLUDE_SERIALGC 179 180 void PSOldGen::precompact() { 181 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 182 183 // Reset start array first. 184 start_array()->reset(); 185 186 object_mark_sweep()->precompact(); 187 188 // Now compact the young gen 189 heap->young_gen()->precompact(); 190 } 191 192 void PSOldGen::adjust_pointers() { 193 object_mark_sweep()->adjust_pointers(); 194 } 195 196 void PSOldGen::compact() { 197 object_mark_sweep()->compact(ZapUnusedHeapArea); 198 } 199 200 #endif // INCLUDE_SERIALGC 201 202 size_t PSOldGen::contiguous_available() const { 203 return object_space()->free_in_bytes() + virtual_space()->uncommitted_size(); 204 } 205 206 // Allocation. We report all successful allocations to the size policy 207 // Note that the perm gen does not use this method, and should not! 208 HeapWord* PSOldGen::allocate(size_t word_size) { 209 assert_locked_or_safepoint(Heap_lock); 210 HeapWord* res = allocate_noexpand(word_size); 211 212 if (res == NULL) { 213 res = expand_and_allocate(word_size); 214 } 215 216 // Allocations in the old generation need to be reported 217 if (res != NULL) { 218 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 219 heap->size_policy()->tenured_allocation(word_size * HeapWordSize); 220 } 221 222 return res; 223 } 224 225 HeapWord* PSOldGen::expand_and_allocate(size_t word_size) { 226 expand(word_size*HeapWordSize); 227 if (GCExpandToAllocateDelayMillis > 0) { 228 os::naked_sleep(GCExpandToAllocateDelayMillis); 229 } 230 return allocate_noexpand(word_size); 231 } 232 233 HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) { 234 expand(word_size*HeapWordSize); 235 if (GCExpandToAllocateDelayMillis > 0) { 236 os::naked_sleep(GCExpandToAllocateDelayMillis); 237 } 238 return cas_allocate_noexpand(word_size); 239 } 240 241 void PSOldGen::expand(size_t bytes) { 242 if (bytes == 0) { 243 return; 244 } 245 MutexLocker x(ExpandHeap_lock); 246 const size_t alignment = virtual_space()->alignment(); 247 size_t aligned_bytes = align_up(bytes, alignment); 248 size_t aligned_expand_bytes = align_up(MinHeapDeltaBytes, alignment); 249 250 if (UseNUMA) { 251 // With NUMA we use round-robin page allocation for the old gen. Expand by at least 252 // providing a page per lgroup. Alignment is larger or equal to the page size. 253 aligned_expand_bytes = MAX2(aligned_expand_bytes, alignment * os::numa_get_groups_num()); 254 } 255 if (aligned_bytes == 0){ 256 // The alignment caused the number of bytes to wrap. An expand_by(0) will 257 // return true with the implication that and expansion was done when it 258 // was not. A call to expand implies a best effort to expand by "bytes" 259 // but not a guarantee. Align down to give a best effort. This is likely 260 // the most that the generation can expand since it has some capacity to 261 // start with. 262 aligned_bytes = align_down(bytes, alignment); 263 } 264 265 bool success = false; 266 if (aligned_expand_bytes > aligned_bytes) { 267 success = expand_by(aligned_expand_bytes); 268 } 269 if (!success) { 270 success = expand_by(aligned_bytes); 271 } 272 if (!success) { 273 success = expand_to_reserved(); 274 } 275 276 if (success && GCLocker::is_active_and_needs_gc()) { 277 log_debug(gc)("Garbage collection disabled, expanded heap instead"); 278 } 279 } 280 281 bool PSOldGen::expand_by(size_t bytes) { 282 assert_lock_strong(ExpandHeap_lock); 283 assert_locked_or_safepoint(Heap_lock); 284 if (bytes == 0) { 285 return true; // That's what virtual_space()->expand_by(0) would return 286 } 287 bool result = virtual_space()->expand_by(bytes); 288 if (result) { 289 if (ZapUnusedHeapArea) { 290 // We need to mangle the newly expanded area. The memregion spans 291 // end -> new_end, we assume that top -> end is already mangled. 292 // Do the mangling before post_resize() is called because 293 // the space is available for allocation after post_resize(); 294 HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high(); 295 assert(object_space()->end() < virtual_space_high, 296 "Should be true before post_resize()"); 297 MemRegion mangle_region(object_space()->end(), virtual_space_high); 298 // Note that the object space has not yet been updated to 299 // coincide with the new underlying virtual space. 300 SpaceMangler::mangle_region(mangle_region); 301 } 302 post_resize(); 303 if (UsePerfData) { 304 _space_counters->update_capacity(); 305 _gen_counters->update_all(); 306 } 307 } 308 309 if (result) { 310 size_t new_mem_size = virtual_space()->committed_size(); 311 size_t old_mem_size = new_mem_size - bytes; 312 log_debug(gc)("Expanding %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K", 313 name(), old_mem_size/K, bytes/K, new_mem_size/K); 314 } 315 316 return result; 317 } 318 319 bool PSOldGen::expand_to_reserved() { 320 assert_lock_strong(ExpandHeap_lock); 321 assert_locked_or_safepoint(Heap_lock); 322 323 bool result = true; 324 const size_t remaining_bytes = virtual_space()->uncommitted_size(); 325 if (remaining_bytes > 0) { 326 result = expand_by(remaining_bytes); 327 DEBUG_ONLY(if (!result) log_warning(gc)("grow to reserve failed")); 328 } 329 return result; 330 } 331 332 void PSOldGen::shrink(size_t bytes) { 333 assert_lock_strong(ExpandHeap_lock); 334 assert_locked_or_safepoint(Heap_lock); 335 336 size_t size = align_down(bytes, virtual_space()->alignment()); 337 if (size > 0) { 338 assert_lock_strong(ExpandHeap_lock); 339 virtual_space()->shrink_by(bytes); 340 post_resize(); 341 342 size_t new_mem_size = virtual_space()->committed_size(); 343 size_t old_mem_size = new_mem_size + bytes; 344 log_debug(gc)("Shrinking %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K", 345 name(), old_mem_size/K, bytes/K, new_mem_size/K); 346 } 347 } 348 349 void PSOldGen::resize(size_t desired_free_space) { 350 const size_t alignment = virtual_space()->alignment(); 351 const size_t size_before = virtual_space()->committed_size(); 352 size_t new_size = used_in_bytes() + desired_free_space; 353 if (new_size < used_in_bytes()) { 354 // Overflowed the addition. 355 new_size = gen_size_limit(); 356 } 357 // Adjust according to our min and max 358 new_size = clamp(new_size, min_gen_size(), gen_size_limit()); 359 360 assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?"); 361 new_size = align_up(new_size, alignment); 362 363 const size_t current_size = capacity_in_bytes(); 364 365 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: " 366 "desired free: " SIZE_FORMAT " used: " SIZE_FORMAT 367 " new size: " SIZE_FORMAT " current size " SIZE_FORMAT 368 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT, 369 desired_free_space, used_in_bytes(), new_size, current_size, 370 gen_size_limit(), min_gen_size()); 371 372 if (new_size == current_size) { 373 // No change requested 374 return; 375 } 376 if (new_size > current_size) { 377 size_t change_bytes = new_size - current_size; 378 expand(change_bytes); 379 } else { 380 size_t change_bytes = current_size - new_size; 381 // shrink doesn't grab this lock, expand does. Is that right? 382 MutexLocker x(ExpandHeap_lock); 383 shrink(change_bytes); 384 } 385 386 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: collection: %d (" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ", 387 ParallelScavengeHeap::heap()->total_collections(), 388 size_before, 389 virtual_space()->committed_size()); 390 } 391 392 // NOTE! We need to be careful about resizing. During a GC, multiple 393 // allocators may be active during heap expansion. If we allow the 394 // heap resizing to become visible before we have correctly resized 395 // all heap related data structures, we may cause program failures. 396 void PSOldGen::post_resize() { 397 // First construct a memregion representing the new size 398 MemRegion new_memregion((HeapWord*)virtual_space()->low(), 399 (HeapWord*)virtual_space()->high()); 400 size_t new_word_size = new_memregion.word_size(); 401 402 start_array()->set_covered_region(new_memregion); 403 ParallelScavengeHeap::heap()->card_table()->resize_covered_region(new_memregion); 404 405 // ALWAYS do this last!! 406 object_space()->initialize(new_memregion, 407 SpaceDecorator::DontClear, 408 SpaceDecorator::DontMangle); 409 410 assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()), 411 "Sanity"); 412 } 413 414 size_t PSOldGen::gen_size_limit() { 415 return _max_gen_size; 416 } 417 418 void PSOldGen::reset_after_change() { 419 ShouldNotReachHere(); 420 return; 421 } 422 423 size_t PSOldGen::available_for_expansion() { 424 ShouldNotReachHere(); 425 return 0; 426 } 427 428 size_t PSOldGen::available_for_contraction() { 429 ShouldNotReachHere(); 430 return 0; 431 } 432 433 void PSOldGen::print() const { print_on(tty);} 434 void PSOldGen::print_on(outputStream* st) const { 435 st->print(" %-15s", name()); 436 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K", 437 capacity_in_bytes()/K, used_in_bytes()/K); 438 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")", 439 p2i(virtual_space()->low_boundary()), 440 p2i(virtual_space()->high()), 441 p2i(virtual_space()->high_boundary())); 442 443 st->print(" object"); object_space()->print_on(st); 444 } 445 446 void PSOldGen::update_counters() { 447 if (UsePerfData) { 448 _space_counters->update_all(); 449 _gen_counters->update_all(); 450 } 451 } 452 453 #ifndef PRODUCT 454 455 void PSOldGen::space_invariants() { 456 assert(object_space()->end() == (HeapWord*) virtual_space()->high(), 457 "Space invariant"); 458 assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(), 459 "Space invariant"); 460 assert(virtual_space()->low_boundary() <= virtual_space()->low(), 461 "Space invariant"); 462 assert(virtual_space()->high_boundary() >= virtual_space()->high(), 463 "Space invariant"); 464 assert(virtual_space()->low_boundary() == (char*) _reserved.start(), 465 "Space invariant"); 466 assert(virtual_space()->high_boundary() == (char*) _reserved.end(), 467 "Space invariant"); 468 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(), 469 "Space invariant"); 470 } 471 #endif 472 473 void PSOldGen::verify() { 474 object_space()->verify(); 475 } 476 class VerifyObjectStartArrayClosure : public ObjectClosure { 477 PSOldGen* _old_gen; 478 ObjectStartArray* _start_array; 479 480 public: 481 VerifyObjectStartArrayClosure(PSOldGen* old_gen, ObjectStartArray* start_array) : 482 _old_gen(old_gen), _start_array(start_array) { } 483 484 virtual void do_object(oop obj) { 485 HeapWord* test_addr = (HeapWord*)obj + 1; 486 guarantee(_start_array->object_start(test_addr) == (HeapWord*)obj, "ObjectStartArray cannot find start of object"); 487 guarantee(_start_array->is_block_allocated((HeapWord*)obj), "ObjectStartArray missing block allocation"); 488 } 489 }; 490 491 void PSOldGen::verify_object_start_array() { 492 VerifyObjectStartArrayClosure check( this, &_start_array ); 493 object_iterate(&check); 494 } 495 496 #ifndef PRODUCT 497 void PSOldGen::record_spaces_top() { 498 assert(ZapUnusedHeapArea, "Not mangling unused space"); 499 object_space()->set_top_for_allocations(); 500 } 501 #endif