1 /* 2 * Copyright (c) 2001, 2009, 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 "incls/_precompiled.incl" 26 # include "incls/_psOldGen.cpp.incl" 27 28 inline const char* PSOldGen::select_name() { 29 return UseParallelOldGC ? "ParOldGen" : "PSOldGen"; 30 } 31 32 PSOldGen::PSOldGen(ReservedSpace rs, size_t alignment, 33 size_t initial_size, size_t min_size, size_t max_size, 34 const char* perf_data_name, int level): 35 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size), 36 _max_gen_size(max_size) 37 { 38 initialize(rs, alignment, perf_data_name, level); 39 } 40 41 PSOldGen::PSOldGen(size_t initial_size, 42 size_t min_size, size_t max_size, 43 const char* perf_data_name, int level): 44 _name(select_name()), _init_gen_size(initial_size), _min_gen_size(min_size), 45 _max_gen_size(max_size) 46 {} 47 48 void PSOldGen::initialize(ReservedSpace rs, size_t alignment, 49 const char* perf_data_name, int level) { 50 initialize_virtual_space(rs, alignment); 51 initialize_work(perf_data_name, level); 52 // The old gen can grow to gen_size_limit(). _reserve reflects only 53 // the current maximum that can be committed. 54 assert(_reserved.byte_size() <= gen_size_limit(), "Consistency check"); 55 } 56 57 void PSOldGen::initialize_virtual_space(ReservedSpace rs, size_t alignment) { 58 59 _virtual_space = new PSVirtualSpace(rs, alignment); 60 if (!_virtual_space->expand_by(_init_gen_size)) { 61 vm_exit_during_initialization("Could not reserve enough space for " 62 "object heap"); 63 } 64 } 65 66 void PSOldGen::initialize_work(const char* perf_data_name, int level) { 67 // 68 // Basic memory initialization 69 // 70 71 MemRegion limit_reserved((HeapWord*)virtual_space()->low_boundary(), 72 heap_word_size(_max_gen_size)); 73 assert(limit_reserved.byte_size() == _max_gen_size, 74 "word vs bytes confusion"); 75 // 76 // Object start stuff 77 // 78 79 start_array()->initialize(limit_reserved); 80 81 _reserved = MemRegion((HeapWord*)virtual_space()->low_boundary(), 82 (HeapWord*)virtual_space()->high_boundary()); 83 84 // 85 // Card table stuff 86 // 87 88 MemRegion cmr((HeapWord*)virtual_space()->low(), 89 (HeapWord*)virtual_space()->high()); 90 if (ZapUnusedHeapArea) { 91 // Mangle newly committed space immediately rather than 92 // waiting for the initialization of the space even though 93 // mangling is related to spaces. Doing it here eliminates 94 // the need to carry along information that a complete mangling 95 // (bottom to end) needs to be done. 96 SpaceMangler::mangle_region(cmr); 97 } 98 99 Universe::heap()->barrier_set()->resize_covered_region(cmr); 100 101 CardTableModRefBS* _ct = (CardTableModRefBS*)Universe::heap()->barrier_set(); 102 assert (_ct->kind() == BarrierSet::CardTableModRef, "Sanity"); 103 104 // Verify that the start and end of this generation is the start of a card. 105 // If this wasn't true, a single card could span more than one generation, 106 // which would cause problems when we commit/uncommit memory, and when we 107 // clear and dirty cards. 108 guarantee(_ct->is_card_aligned(_reserved.start()), "generation must be card aligned"); 109 if (_reserved.end() != Universe::heap()->reserved_region().end()) { 110 // Don't check at the very end of the heap as we'll assert that we're probing off 111 // the end if we try. 112 guarantee(_ct->is_card_aligned(_reserved.end()), "generation must be card aligned"); 113 } 114 115 // 116 // ObjectSpace stuff 117 // 118 119 _object_space = new MutableSpace(virtual_space()->alignment()); 120 121 if (_object_space == NULL) 122 vm_exit_during_initialization("Could not allocate an old gen space"); 123 124 object_space()->initialize(cmr, 125 SpaceDecorator::Clear, 126 SpaceDecorator::Mangle); 127 128 _object_mark_sweep = new PSMarkSweepDecorator(_object_space, start_array(), MarkSweepDeadRatio); 129 130 if (_object_mark_sweep == NULL) 131 vm_exit_during_initialization("Could not complete allocation of old generation"); 132 133 // Update the start_array 134 start_array()->set_covered_region(cmr); 135 136 // Generation Counters, generation 'level', 1 subspace 137 _gen_counters = new PSGenerationCounters(perf_data_name, level, 1, 138 virtual_space()); 139 _space_counters = new SpaceCounters(perf_data_name, 0, 140 virtual_space()->reserved_size(), 141 _object_space, _gen_counters); 142 } 143 144 // Assume that the generation has been allocated if its 145 // reserved size is not 0. 146 bool PSOldGen::is_allocated() { 147 return virtual_space()->reserved_size() != 0; 148 } 149 150 void PSOldGen::precompact() { 151 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 152 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); 153 154 // Reset start array first. 155 start_array()->reset(); 156 157 object_mark_sweep()->precompact(); 158 159 // Now compact the young gen 160 heap->young_gen()->precompact(); 161 } 162 163 void PSOldGen::adjust_pointers() { 164 object_mark_sweep()->adjust_pointers(); 165 } 166 167 void PSOldGen::compact() { 168 object_mark_sweep()->compact(ZapUnusedHeapArea); 169 } 170 171 void PSOldGen::move_and_update(ParCompactionManager* cm) { 172 PSParallelCompact::move_and_update(cm, PSParallelCompact::old_space_id); 173 } 174 175 size_t PSOldGen::contiguous_available() const { 176 return object_space()->free_in_bytes() + virtual_space()->uncommitted_size(); 177 } 178 179 // Allocation. We report all successful allocations to the size policy 180 // Note that the perm gen does not use this method, and should not! 181 HeapWord* PSOldGen::allocate(size_t word_size, bool is_tlab) { 182 assert_locked_or_safepoint(Heap_lock); 183 HeapWord* res = allocate_noexpand(word_size, is_tlab); 184 185 if (res == NULL) { 186 res = expand_and_allocate(word_size, is_tlab); 187 } 188 189 // Allocations in the old generation need to be reported 190 if (res != NULL) { 191 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 192 heap->size_policy()->tenured_allocation(word_size); 193 } 194 195 return res; 196 } 197 198 HeapWord* PSOldGen::expand_and_allocate(size_t word_size, bool is_tlab) { 199 assert(!is_tlab, "TLAB's are not supported in PSOldGen"); 200 expand(word_size*HeapWordSize); 201 if (GCExpandToAllocateDelayMillis > 0) { 202 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false); 203 } 204 return allocate_noexpand(word_size, is_tlab); 205 } 206 207 HeapWord* PSOldGen::expand_and_cas_allocate(size_t word_size) { 208 expand(word_size*HeapWordSize); 209 if (GCExpandToAllocateDelayMillis > 0) { 210 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false); 211 } 212 return cas_allocate_noexpand(word_size); 213 } 214 215 void PSOldGen::expand(size_t bytes) { 216 if (bytes == 0) { 217 return; 218 } 219 MutexLocker x(ExpandHeap_lock); 220 const size_t alignment = virtual_space()->alignment(); 221 size_t aligned_bytes = align_size_up(bytes, alignment); 222 size_t aligned_expand_bytes = align_size_up(MinHeapDeltaBytes, alignment); 223 if (aligned_bytes == 0){ 224 // The alignment caused the number of bytes to wrap. An expand_by(0) will 225 // return true with the implication that and expansion was done when it 226 // was not. A call to expand implies a best effort to expand by "bytes" 227 // but not a guarantee. Align down to give a best effort. This is likely 228 // the most that the generation can expand since it has some capacity to 229 // start with. 230 aligned_bytes = align_size_down(bytes, alignment); 231 } 232 233 bool success = false; 234 if (aligned_expand_bytes > aligned_bytes) { 235 success = expand_by(aligned_expand_bytes); 236 } 237 if (!success) { 238 success = expand_by(aligned_bytes); 239 } 240 if (!success) { 241 success = expand_to_reserved(); 242 } 243 244 if (PrintGC && Verbose) { 245 if (success && GC_locker::is_active()) { 246 gclog_or_tty->print_cr("Garbage collection disabled, expanded heap instead"); 247 } 248 } 249 } 250 251 bool PSOldGen::expand_by(size_t bytes) { 252 assert_lock_strong(ExpandHeap_lock); 253 assert_locked_or_safepoint(Heap_lock); 254 if (bytes == 0) { 255 return true; // That's what virtual_space()->expand_by(0) would return 256 } 257 bool result = virtual_space()->expand_by(bytes); 258 if (result) { 259 if (ZapUnusedHeapArea) { 260 // We need to mangle the newly expanded area. The memregion spans 261 // end -> new_end, we assume that top -> end is already mangled. 262 // Do the mangling before post_resize() is called because 263 // the space is available for allocation after post_resize(); 264 HeapWord* const virtual_space_high = (HeapWord*) virtual_space()->high(); 265 assert(object_space()->end() < virtual_space_high, 266 "Should be true before post_resize()"); 267 MemRegion mangle_region(object_space()->end(), virtual_space_high); 268 // Note that the object space has not yet been updated to 269 // coincede with the new underlying virtual space. 270 SpaceMangler::mangle_region(mangle_region); 271 } 272 post_resize(); 273 if (UsePerfData) { 274 _space_counters->update_capacity(); 275 _gen_counters->update_all(); 276 } 277 } 278 279 if (result && Verbose && PrintGC) { 280 size_t new_mem_size = virtual_space()->committed_size(); 281 size_t old_mem_size = new_mem_size - bytes; 282 gclog_or_tty->print_cr("Expanding %s from " SIZE_FORMAT "K by " 283 SIZE_FORMAT "K to " 284 SIZE_FORMAT "K", 285 name(), old_mem_size/K, bytes/K, new_mem_size/K); 286 } 287 288 return result; 289 } 290 291 bool PSOldGen::expand_to_reserved() { 292 assert_lock_strong(ExpandHeap_lock); 293 assert_locked_or_safepoint(Heap_lock); 294 295 bool result = true; 296 const size_t remaining_bytes = virtual_space()->uncommitted_size(); 297 if (remaining_bytes > 0) { 298 result = expand_by(remaining_bytes); 299 DEBUG_ONLY(if (!result) warning("grow to reserve failed")); 300 } 301 return result; 302 } 303 304 void PSOldGen::shrink(size_t bytes) { 305 assert_lock_strong(ExpandHeap_lock); 306 assert_locked_or_safepoint(Heap_lock); 307 308 size_t size = align_size_down(bytes, virtual_space()->alignment()); 309 if (size > 0) { 310 assert_lock_strong(ExpandHeap_lock); 311 virtual_space()->shrink_by(bytes); 312 post_resize(); 313 314 if (Verbose && PrintGC) { 315 size_t new_mem_size = virtual_space()->committed_size(); 316 size_t old_mem_size = new_mem_size + bytes; 317 gclog_or_tty->print_cr("Shrinking %s from " SIZE_FORMAT "K by " 318 SIZE_FORMAT "K to " 319 SIZE_FORMAT "K", 320 name(), old_mem_size/K, bytes/K, new_mem_size/K); 321 } 322 } 323 } 324 325 void PSOldGen::resize(size_t desired_free_space) { 326 const size_t alignment = virtual_space()->alignment(); 327 const size_t size_before = virtual_space()->committed_size(); 328 size_t new_size = used_in_bytes() + desired_free_space; 329 if (new_size < used_in_bytes()) { 330 // Overflowed the addition. 331 new_size = gen_size_limit(); 332 } 333 // Adjust according to our min and max 334 new_size = MAX2(MIN2(new_size, gen_size_limit()), min_gen_size()); 335 336 assert(gen_size_limit() >= reserved().byte_size(), "max new size problem?"); 337 new_size = align_size_up(new_size, alignment); 338 339 const size_t current_size = capacity_in_bytes(); 340 341 if (PrintAdaptiveSizePolicy && Verbose) { 342 gclog_or_tty->print_cr("AdaptiveSizePolicy::old generation size: " 343 "desired free: " SIZE_FORMAT " used: " SIZE_FORMAT 344 " new size: " SIZE_FORMAT " current size " SIZE_FORMAT 345 " gen limits: " SIZE_FORMAT " / " SIZE_FORMAT, 346 desired_free_space, used_in_bytes(), new_size, current_size, 347 gen_size_limit(), min_gen_size()); 348 } 349 350 if (new_size == current_size) { 351 // No change requested 352 return; 353 } 354 if (new_size > current_size) { 355 size_t change_bytes = new_size - current_size; 356 expand(change_bytes); 357 } else { 358 size_t change_bytes = current_size - new_size; 359 // shrink doesn't grab this lock, expand does. Is that right? 360 MutexLocker x(ExpandHeap_lock); 361 shrink(change_bytes); 362 } 363 364 if (PrintAdaptiveSizePolicy) { 365 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); 366 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); 367 gclog_or_tty->print_cr("AdaptiveSizePolicy::old generation size: " 368 "collection: %d " 369 "(" SIZE_FORMAT ") -> (" SIZE_FORMAT ") ", 370 heap->total_collections(), 371 size_before, virtual_space()->committed_size()); 372 } 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 Universe::heap()->barrier_set()->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 if (PrintGCDetails && Verbose) { 420 st->print(" total " SIZE_FORMAT ", used " SIZE_FORMAT, 421 capacity_in_bytes(), used_in_bytes()); 422 } else { 423 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K", 424 capacity_in_bytes()/K, used_in_bytes()/K); 425 } 426 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")", 427 virtual_space()->low_boundary(), 428 virtual_space()->high(), 429 virtual_space()->high_boundary()); 430 431 st->print(" object"); object_space()->print_on(st); 432 } 433 434 void PSOldGen::print_used_change(size_t prev_used) const { 435 gclog_or_tty->print(" [%s:", name()); 436 gclog_or_tty->print(" " SIZE_FORMAT "K" 437 "->" SIZE_FORMAT "K" 438 "(" SIZE_FORMAT "K)", 439 prev_used / K, used_in_bytes() / K, 440 capacity_in_bytes() / K); 441 gclog_or_tty->print("]"); 442 } 443 444 void PSOldGen::update_counters() { 445 if (UsePerfData) { 446 _space_counters->update_all(); 447 _gen_counters->update_all(); 448 } 449 } 450 451 #ifndef PRODUCT 452 453 void PSOldGen::space_invariants() { 454 assert(object_space()->end() == (HeapWord*) virtual_space()->high(), 455 "Space invariant"); 456 assert(object_space()->bottom() == (HeapWord*) virtual_space()->low(), 457 "Space invariant"); 458 assert(virtual_space()->low_boundary() <= virtual_space()->low(), 459 "Space invariant"); 460 assert(virtual_space()->high_boundary() >= virtual_space()->high(), 461 "Space invariant"); 462 assert(virtual_space()->low_boundary() == (char*) _reserved.start(), 463 "Space invariant"); 464 assert(virtual_space()->high_boundary() == (char*) _reserved.end(), 465 "Space invariant"); 466 assert(virtual_space()->committed_size() <= virtual_space()->reserved_size(), 467 "Space invariant"); 468 } 469 #endif 470 471 void PSOldGen::verify(bool allow_dirty) { 472 object_space()->verify(allow_dirty); 473 } 474 class VerifyObjectStartArrayClosure : public ObjectClosure { 475 PSOldGen* _gen; 476 ObjectStartArray* _start_array; 477 478 public: 479 VerifyObjectStartArrayClosure(PSOldGen* gen, ObjectStartArray* start_array) : 480 _gen(gen), _start_array(start_array) { } 481 482 virtual void do_object(oop obj) { 483 HeapWord* test_addr = (HeapWord*)obj + 1; 484 guarantee(_start_array->object_start(test_addr) == (HeapWord*)obj, "ObjectStartArray cannot find start of object"); 485 guarantee(_start_array->is_block_allocated((HeapWord*)obj), "ObjectStartArray missing block allocation"); 486 } 487 }; 488 489 void PSOldGen::verify_object_start_array() { 490 VerifyObjectStartArrayClosure check( this, &_start_array ); 491 object_iterate(&check); 492 } 493 494 #ifndef PRODUCT 495 void PSOldGen::record_spaces_top() { 496 assert(ZapUnusedHeapArea, "Not mangling unused space"); 497 object_space()->set_top_for_allocations(); 498 } 499 #endif