1 /* 2 * Copyright (c) 2001, 2016, 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/parallelScavengeHeap.hpp" 28 #include "gc/parallel/psAdaptiveSizePolicy.hpp" 29 #include "gc/parallel/psMarkSweepDecorator.hpp" 30 #include "gc/parallel/psOldGen.hpp" 31 #include "gc/shared/cardTableModRefBS.hpp" 32 #include "gc/shared/gcLocker.inline.hpp" 33 #include "gc/shared/spaceDecorator.hpp" 34 #include "logging/log.hpp" 35 #include "oops/oop.inline.hpp" 36 #include "runtime/java.hpp" 37 38 inline const char* PSOldGen::select_name() { 39 return UseParallelOldGC ? "ParOldGen" : "PSOldGen"; 40 } 41 42 PSOldGen::PSOldGen(ReservedSpace rs, size_t alignment, 43 size_t initial_size, size_t min_size, size_t max_size, 44 const char* perf_data_name, int level): 45 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size), 46 _max_gen_size(max_size) 47 { 48 initialize(rs, alignment, perf_data_name, level); 49 } 50 51 PSOldGen::PSOldGen(size_t initial_size, 52 size_t min_size, size_t max_size, 53 const char* perf_data_name, int level): 54 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size), 55 _max_gen_size(max_size) 56 {} 57 58 void PSOldGen::initialize(ReservedSpace rs, size_t alignment, 59 const char* perf_data_name, int level) { 60 initialize_virtual_space(rs, alignment); 61 initialize_work(perf_data_name, level); 62 63 // The old gen can grow to gen_size_limit(). _reserve reflects only 64 // the current maximum that can be committed. 65 assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check"); 66 67 initialize_performance_counters(perf_data_name, level); 68 } 69 70 void PSOldGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) { 71 72 _virtual_space = new PSVirtualSpace(rs, alignment); 73 if (!_virtual_space->expand_by(_init_gen_size)) { 74 vm_exit_during_initialization("Could not reserve enough space for " 75 "object heap"); 76 } 77 } 78 79 void PSOldGen::initialize_work(const char* perf_data_name, int level) { 80 // 81 // Basic memory initialization 82 // 83 84 MemRegion limit_reserved((HeapWord*)virtual_space()->low_boundary(), 85 heap_word_size(_max_gen_size)); 86 assert(limit_reserved.byte_size() == _max_gen_size, 87 "word vs bytes confusion"); 88 // 89 // Object start stuff 90 // 91 92 start_array()->initialize(limit_reserved); 93 94 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(), 95 (HeapWord*)virtual_space()->high_boundary()); 96 97 // 98 // Card table stuff 99 // 100 101 MemRegion cmr((HeapWord*)virtual_space()->low(), 102 (HeapWord*)virtual_space()->high()); 103 if (ZapUnusedHeapArea) { 104 // Mangle newly committed space immediately rather than 105 // waiting for the initialization of the space even though 106 // mangling is related to spaces. Doing it here eliminates 107 // the need to carry along information that a complete mangling 108 // (bottom to end) needs to be done. 109 SpaceMangler::mangle_region(cmr); 110 } 111 112 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 113 PSCardTable* ct = heap->card_table(); 114 115 ct->resize_covered_region(cmr); 116 117 // Verify that the start and end of this generation is the start of a card. 118 // If this wasn't true, a single card could span more than one generation, 119 // which would cause problems when we commit/uncommit memory, and when we 120 // clear and dirty cards. 121 guarantee(ct->is_card_aligned(_reserved.start()), "generation must be card aligned"); 122 if (_reserved.end() != heap->reserved_region().end()) { 123 // Don't check at the very end of the heap as we'll assert that we're probing off 124 // the end if we try. 125 guarantee(ct->is_card_aligned(_reserved.end()), "generation must be card aligned"); 126 } 127 128 // 129 // ObjectSpace stuff 130 // 131 132 _object_space = new MutableSpace(virtual_space()->alignment()); 133 134 if (_object_space == NULL) 135 vm_exit_during_initialization("Could not allocate an old gen space"); 136 137 object_space()->initialize(cmr, 138 SpaceDecorator::Clear, 139 SpaceDecorator::Mangle); 140 141 _object_mark_sweep = new PSMarkSweepDecorator(_object_space, start_array(), MarkSweepDeadRatio); 142 143 if (_object_mark_sweep == NULL) 144 vm_exit_during_initialization("Could not complete allocation of old generation"); 145 146 // Update the start_array 147 start_array()->set_covered_region(cmr); 148 } 149 150 void PSOldGen::initialize_performance_counters(const char* perf_data_name, int level) { 151 // Generation Counters, generation 'level', 1 subspace 152 _gen_counters = new PSGenerationCounters(perf_data_name, level, 1, _min_gen_size, 153 _max_gen_size, virtual_space()); 154 _space_counters = new SpaceCounters(perf_data_name, 0, 155 virtual_space()->reserved_size(), 156 _object_space, _gen_counters); 157 } 158 159 // Assume that the generation has been allocated if its 160 // reserved size is not 0. 161 bool PSOldGen::is_allocated() { 162 return virtual_space()->reserved_size() != 0; 163 } 164 165 void PSOldGen::precompact() { 166 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 167 168 // Reset start array first. 169 start_array()->reset(); 170 171 object_mark_sweep()->precompact(); 172 173 // Now compact the young gen 174 heap->young_gen()->precompact(); 175 } 176 177 void PSOldGen::adjust_pointers() { 178 object_mark_sweep()->adjust_pointers(); 179 } 180 181 void PSOldGen::compact() { 182 object_mark_sweep()->compact(ZapUnusedHeapArea); 183 } 184 185 size_t PSOldGen::contiguous_available() const { 186 return object_space()->free_in_bytes() + virtual_space()->uncommitted_size(); 187 } 188 189 // Allocation. We report all successful allocations to the size policy 190 // Note that the perm gen does not use this method, and should not! 191 HeapWord* PSOldGen::allocate(size_t word_size) { 192 assert_locked_or_safepoint(Heap_lock); 193 HeapWord* res = allocate_noexpand(word_size); 194 195 if (res == NULL) { 196 res = expand_and_allocate(word_size); 197 } 198 199 // Allocations in the old generation need to be reported 200 if (res != NULL) { 201 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap(); 202 heap->size_policy()->tenured_allocation(word_size * HeapWordSize); 203 } 204 205 return res; 206 } 207 208 HeapWord* PSOldGen::expand_and_allocate(size_t word_size) { 209 expand(word_size*HeapWordSize); 210 if (GCExpandToAllocateDelayMillis > 0) { 211 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false); 212 } 213 return allocate_noexpand(word_size); 214 } 215 216 HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) { 217 expand(word_size*HeapWordSize); 218 if (GCExpandToAllocateDelayMillis > 0) { 219 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false); 220 } 221 return cas_allocate_noexpand(word_size); 222 } 223 224 void PSOldGen::expand(size_t bytes) { 225 if (bytes == 0) { 226 return; 227 } 228 MutexLocker x(ExpandHeap_lock); 229 const size_t alignment = virtual_space()->alignment(); 230 size_t aligned_bytes = align_size_up(bytes, alignment); 231 size_t aligned_expand_bytes = align_size_up(MinHeapDeltaBytes, alignment); 232 233 if (UseNUMA) { 234 // With NUMA we use round-robin page allocation for the old gen. Expand by at least 235 // providing a page per lgroup. Alignment is larger or equal to the page size. 236 aligned_expand_bytes = MAX2(aligned_expand_bytes, alignment * os::numa_get_groups_num()); 237 } 238 if (aligned_bytes == 0){ 239 // The alignment caused the number of bytes to wrap. An expand_by(0) will 240 // return true with the implication that and expansion was done when it 241 // was not. A call to expand implies a best effort to expand by "bytes" 242 // but not a guarantee. Align down to give a best effort. This is likely 243 // the most that the generation can expand since it has some capacity to 244 // start with. 245 aligned_bytes = align_size_down(bytes, alignment); 246 } 247 248 bool success = false; 249 if (aligned_expand_bytes > aligned_bytes) { 250 success = expand_by(aligned_expand_bytes); 251 } 252 if (!success) { 253 success = expand_by(aligned_bytes); 254 } 255 if (!success) { 256 success = expand_to_reserved(); 257 } 258 259 if (success && GCLocker::is_active_and_needs_gc()) { 260 log_debug(gc)("Garbage collection disabled, expanded heap instead"); 261 } 262 } 263 264 bool PSOldGen::expand_by(size_t bytes) { 265 assert_lock_strong(ExpandHeap_lock); 266 assert_locked_or_safepoint(Heap_lock); 267 if (bytes == 0) { 268 return true; // That's what virtual_space()->expand_by(0) would return 269 } 270 bool result = virtual_space()->expand_by(bytes); 271 if (result) { 272 if (ZapUnusedHeapArea) { 273 // We need to mangle the newly expanded area. The memregion spans 274 // end -> new_end, we assume that top -> end is already mangled. 275 // Do the mangling before post_resize() is called because 276 // the space is available for allocation after post_resize(); 277 HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high(); 278 assert(object_space()->end() < virtual_space_high, 279 "Should be true before post_resize()"); 280 MemRegion mangle_region(object_space()->end(), virtual_space_high); 281 // Note that the object space has not yet been updated to 282 // coincide with the new underlying virtual space. 283 SpaceMangler::mangle_region(mangle_region); 284 } 285 post_resize(); 286 if (UsePerfData) { 287 _space_counters->update_capacity(); 288 _gen_counters->update_all(); 289 } 290 } 291 292 if (result) { 293 size_t new_mem_size = virtual_space()->committed_size(); 294 size_t old_mem_size = new_mem_size - bytes; 295 log_debug(gc)("Expanding %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K", 296 name(), old_mem_size/K, bytes/K, new_mem_size/K); 297 } 298 299 return result; 300 } 301 302 bool PSOldGen::expand_to_reserved() { 303 assert_lock_strong(ExpandHeap_lock); 304 assert_locked_or_safepoint(Heap_lock); 305 306 bool result = true; 307 const size_t remaining_bytes = virtual_space()->uncommitted_size(); 308 if (remaining_bytes > 0) { 309 result = expand_by(remaining_bytes); 310 DEBUG_ONLY(if (!result) log_warning(gc)("grow to reserve failed")); 311 } 312 return result; 313 } 314 315 void PSOldGen::shrink(size_t bytes) { 316 assert_lock_strong(ExpandHeap_lock); 317 assert_locked_or_safepoint(Heap_lock); 318 319 size_t size = align_size_down(bytes, virtual_space()->alignment()); 320 if (size > 0) { 321 assert_lock_strong(ExpandHeap_lock); 322 virtual_space()->shrink_by(bytes); 323 post_resize(); 324 325 size_t new_mem_size = virtual_space()->committed_size(); 326 size_t old_mem_size = new_mem_size + bytes; 327 log_debug(gc)("Shrinking %s from " SIZE_FORMAT "K by " SIZE_FORMAT "K to " SIZE_FORMAT "K", 328 name(), old_mem_size/K, bytes/K, new_mem_size/K); 329 } 330 } 331 332 void PSOldGen::resize(size_t desired_free_space) { 333 const size_t alignment = virtual_space()->alignment(); 334 const size_t size_before = virtual_space()->committed_size(); 335 size_t new_size = used_in_bytes() + desired_free_space; 336 if (new_size < used_in_bytes()) { 337 // Overflowed the addition. 338 new_size = gen_size_limit(); 339 } 340 // Adjust according to our min and max 341 new_size = MAX2(MIN2(new_size, gen_size_limit()), min_gen_size()); 342 343 assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?"); 344 new_size = align_size_up(new_size, alignment); 345 346 const size_t current_size = capacity_in_bytes(); 347 348 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: " 349 "desired free: " SIZE_FORMAT " used: " SIZE_FORMAT 350 " new size: " SIZE_FORMAT " current size " SIZE_FORMAT 351 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT, 352 desired_free_space, used_in_bytes(), new_size, current_size, 353 gen_size_limit(), min_gen_size()); 354 355 if (new_size == current_size) { 356 // No change requested 357 return; 358 } 359 if (new_size > current_size) { 360 size_t change_bytes = new_size - current_size; 361 expand(change_bytes); 362 } else { 363 size_t change_bytes = current_size - new_size; 364 // shrink doesn't grab this lock, expand does. Is that right? 365 MutexLocker x(ExpandHeap_lock); 366 shrink(change_bytes); 367 } 368 369 log_trace(gc, ergo)("AdaptiveSizePolicy::old generation size: collection: %d (" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ", 370 ParallelScavengeHeap::heap()->total_collections(), 371 size_before, 372 virtual_space()->committed_size()); 373 } 374 375 // NOTE! We need to be careful about resizing. During a GC, multiple 376 // allocators may be active during heap expansion. If we allow the 377 // heap resizing to become visible before we have correctly resized 378 // all heap related data structures, we may cause program failures. 379 void PSOldGen::post_resize() { 380 // First construct a memregion representing the new size 381 MemRegion new_memregion((HeapWord*)virtual_space()->low(), 382 (HeapWord*)virtual_space()->high()); 383 size_t new_word_size = new_memregion.word_size(); 384 385 start_array()->set_covered_region(new_memregion); 386 ParallelScavengeHeap::heap()->card_table()->resize_covered_region(new_memregion); 387 388 // ALWAYS do this last!! 389 object_space()->initialize(new_memregion, 390 SpaceDecorator::DontClear, 391 SpaceDecorator::DontMangle); 392 393 assert(new_word_size == heap_word_size(object_space()->capacity_in_bytes()), 394 "Sanity"); 395 } 396 397 size_t PSOldGen::gen_size_limit() { 398 return _max_gen_size; 399 } 400 401 void PSOldGen::reset_after_change() { 402 ShouldNotReachHere(); 403 return; 404 } 405 406 size_t PSOldGen::available_for_expansion() { 407 ShouldNotReachHere(); 408 return 0; 409 } 410 411 size_t PSOldGen::available_for_contraction() { 412 ShouldNotReachHere(); 413 return 0; 414 } 415 416 void PSOldGen::print() const { print_on(tty);} 417 void PSOldGen::print_on(outputStream* st) const { 418 st->print(" %-15s", name()); 419 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K", 420 capacity_in_bytes()/K, used_in_bytes()/K); 421 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")", 422 p2i(virtual_space()->low_boundary()), 423 p2i(virtual_space()->high()), 424 p2i(virtual_space()->high_boundary())); 425 426 st->print(" object"); object_space()->print_on(st); 427 } 428 429 void PSOldGen::print_used_change(size_t prev_used) const { 430 log_info(gc, heap)("%s: " SIZE_FORMAT "K->" SIZE_FORMAT "K(" SIZE_FORMAT "K)", 431 name(), prev_used / K, used_in_bytes() / K, capacity_in_bytes() / K); 432 } 433 434 void PSOldGen::update_counters() { 435 if (UsePerfData) { 436 _space_counters->update_all(); 437 _gen_counters->update_all(); 438 } 439 } 440 441 #ifndef PRODUCT 442 443 void PSOldGen::space_invariants() { 444 assert(object_space()->end() == (HeapWord*) virtual_space()->high(), 445 "Space invariant"); 446 assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(), 447 "Space invariant"); 448 assert(virtual_space()->low_boundary() <= virtual_space()->low(), 449 "Space invariant"); 450 assert(virtual_space()->high_boundary() >= virtual_space()->high(), 451 "Space invariant"); 452 assert(virtual_space()->low_boundary() == (char*) _reserved.start(), 453 "Space invariant"); 454 assert(virtual_space()->high_boundary() == (char*) _reserved.end(), 455 "Space invariant"); 456 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(), 457 "Space invariant"); 458 } 459 #endif 460 461 void PSOldGen::verify() { 462 object_space()->verify(); 463 } 464 class VerifyObjectStartArrayClosure : public ObjectClosure { 465 PSOldGen* _old_gen; 466 ObjectStartArray* _start_array; 467 468 public: 469 VerifyObjectStartArrayClosure(PSOldGen* old_gen, ObjectStartArray* start_array) : 470 _old_gen(old_gen), _start_array(start_array) { } 471 472 virtual void do_object(oop obj) { 473 HeapWord* test_addr = (HeapWord*)obj + 1; 474 guarantee(_start_array->object_start(test_addr) == (HeapWord*)obj, "ObjectStartArray cannot find start of object"); 475 guarantee(_start_array->is_block_allocated((HeapWord*)obj), "ObjectStartArray missing block allocation"); 476 } 477 }; 478 479 void PSOldGen::verify_object_start_array() { 480 VerifyObjectStartArrayClosure check( this, &_start_array ); 481 object_iterate(&check); 482 } 483 484 #ifndef PRODUCT 485 void PSOldGen::record_spaces_top() { 486 assert(ZapUnusedHeapArea, "Not mangling unused space"); 487 object_space()->set_top_for_allocations(); 488 } 489 #endif