1 /* 2 * Copyright (c) 2005, 2015, 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 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSPARALLELCOMPACT_HPP 26 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSPARALLELCOMPACT_HPP 27 28 #include "gc_implementation/parallelScavenge/objectStartArray.hpp" 29 #include "gc_implementation/parallelScavenge/parMarkBitMap.hpp" 30 #include "gc_implementation/parallelScavenge/psCompactionManager.hpp" 31 #include "gc_implementation/shared/collectorCounters.hpp" 32 #include "gc_implementation/shared/mutableSpace.hpp" 33 #include "memory/sharedHeap.hpp" 34 #include "oops/oop.hpp" 35 36 class ParallelScavengeHeap; 37 class PSAdaptiveSizePolicy; 38 class PSYoungGen; 39 class PSOldGen; 40 class ParCompactionManager; 41 class ParallelTaskTerminator; 42 class PSParallelCompact; 43 class GCTaskManager; 44 class GCTaskQueue; 45 class PreGCValues; 46 class MoveAndUpdateClosure; 47 class RefProcTaskExecutor; 48 class ParallelOldTracer; 49 class STWGCTimer; 50 51 // The SplitInfo class holds the information needed to 'split' a source region 52 // so that the live data can be copied to two destination *spaces*. Normally, 53 // all the live data in a region is copied to a single destination space (e.g., 54 // everything live in a region in eden is copied entirely into the old gen). 55 // However, when the heap is nearly full, all the live data in eden may not fit 56 // into the old gen. Copying only some of the regions from eden to old gen 57 // requires finding a region that does not contain a partial object (i.e., no 58 // live object crosses the region boundary) somewhere near the last object that 59 // does fit into the old gen. Since it's not always possible to find such a 60 // region, splitting is necessary for predictable behavior. 61 // 62 // A region is always split at the end of the partial object. This avoids 63 // additional tests when calculating the new location of a pointer, which is a 64 // very hot code path. The partial object and everything to its left will be 65 // copied to another space (call it dest_space_1). The live data to the right 66 // of the partial object will be copied either within the space itself, or to a 67 // different destination space (distinct from dest_space_1). 68 // 69 // Split points are identified during the summary phase, when region 70 // destinations are computed: data about the split, including the 71 // partial_object_size, is recorded in a SplitInfo record and the 72 // partial_object_size field in the summary data is set to zero. The zeroing is 73 // possible (and necessary) since the partial object will move to a different 74 // destination space than anything to its right, thus the partial object should 75 // not affect the locations of any objects to its right. 76 // 77 // The recorded data is used during the compaction phase, but only rarely: when 78 // the partial object on the split region will be copied across a destination 79 // region boundary. This test is made once each time a region is filled, and is 80 // a simple address comparison, so the overhead is negligible (see 81 // PSParallelCompact::first_src_addr()). 82 // 83 // Notes: 84 // 85 // Only regions with partial objects are split; a region without a partial 86 // object does not need any extra bookkeeping. 87 // 88 // At most one region is split per space, so the amount of data required is 89 // constant. 90 // 91 // A region is split only when the destination space would overflow. Once that 92 // happens, the destination space is abandoned and no other data (even from 93 // other source spaces) is targeted to that destination space. Abandoning the 94 // destination space may leave a somewhat large unused area at the end, if a 95 // large object caused the overflow. 96 // 97 // Future work: 98 // 99 // More bookkeeping would be required to continue to use the destination space. 100 // The most general solution would allow data from regions in two different 101 // source spaces to be "joined" in a single destination region. At the very 102 // least, additional code would be required in next_src_region() to detect the 103 // join and skip to an out-of-order source region. If the join region was also 104 // the last destination region to which a split region was copied (the most 105 // likely case), then additional work would be needed to get fill_region() to 106 // stop iteration and switch to a new source region at the right point. Basic 107 // idea would be to use a fake value for the top of the source space. It is 108 // doable, if a bit tricky. 109 // 110 // A simpler (but less general) solution would fill the remainder of the 111 // destination region with a dummy object and continue filling the next 112 // destination region. 113 114 class SplitInfo 115 { 116 public: 117 // Return true if this split info is valid (i.e., if a split has been 118 // recorded). The very first region cannot have a partial object and thus is 119 // never split, so 0 is the 'invalid' value. 120 bool is_valid() const { return _src_region_idx > 0; } 121 122 // Return true if this split holds data for the specified source region. 123 inline bool is_split(size_t source_region) const; 124 125 // The index of the split region, the size of the partial object on that 126 // region and the destination of the partial object. 127 size_t src_region_idx() const { return _src_region_idx; } 128 size_t partial_obj_size() const { return _partial_obj_size; } 129 HeapWord* destination() const { return _destination; } 130 131 // The destination count of the partial object referenced by this split 132 // (either 1 or 2). This must be added to the destination count of the 133 // remainder of the source region. 134 unsigned int destination_count() const { return _destination_count; } 135 136 // If a word within the partial object will be written to the first word of a 137 // destination region, this is the address of the destination region; 138 // otherwise this is NULL. 139 HeapWord* dest_region_addr() const { return _dest_region_addr; } 140 141 // If a word within the partial object will be written to the first word of a 142 // destination region, this is the address of that word within the partial 143 // object; otherwise this is NULL. 144 HeapWord* first_src_addr() const { return _first_src_addr; } 145 146 // Record the data necessary to split the region src_region_idx. 147 void record(size_t src_region_idx, size_t partial_obj_size, 148 HeapWord* destination); 149 150 void clear(); 151 152 DEBUG_ONLY(void verify_clear();) 153 154 private: 155 size_t _src_region_idx; 156 size_t _partial_obj_size; 157 HeapWord* _destination; 158 unsigned int _destination_count; 159 HeapWord* _dest_region_addr; 160 HeapWord* _first_src_addr; 161 }; 162 163 inline bool SplitInfo::is_split(size_t region_idx) const 164 { 165 return _src_region_idx == region_idx && is_valid(); 166 } 167 168 class SpaceInfo 169 { 170 public: 171 MutableSpace* space() const { return _space; } 172 173 // Where the free space will start after the collection. Valid only after the 174 // summary phase completes. 175 HeapWord* new_top() const { return _new_top; } 176 177 // Allows new_top to be set. 178 HeapWord** new_top_addr() { return &_new_top; } 179 180 // Where the smallest allowable dense prefix ends (used only for perm gen). 181 HeapWord* min_dense_prefix() const { return _min_dense_prefix; } 182 183 // Where the dense prefix ends, or the compacted region begins. 184 HeapWord* dense_prefix() const { return _dense_prefix; } 185 186 // The start array for the (generation containing the) space, or NULL if there 187 // is no start array. 188 ObjectStartArray* start_array() const { return _start_array; } 189 190 SplitInfo& split_info() { return _split_info; } 191 192 void set_space(MutableSpace* s) { _space = s; } 193 void set_new_top(HeapWord* addr) { _new_top = addr; } 194 void set_min_dense_prefix(HeapWord* addr) { _min_dense_prefix = addr; } 195 void set_dense_prefix(HeapWord* addr) { _dense_prefix = addr; } 196 void set_start_array(ObjectStartArray* s) { _start_array = s; } 197 198 void publish_new_top() const { _space->set_top(_new_top); } 199 200 private: 201 MutableSpace* _space; 202 HeapWord* _new_top; 203 HeapWord* _min_dense_prefix; 204 HeapWord* _dense_prefix; 205 ObjectStartArray* _start_array; 206 SplitInfo _split_info; 207 }; 208 209 class ParallelCompactData 210 { 211 public: 212 // Sizes are in HeapWords, unless indicated otherwise. 213 static const size_t Log2RegionSize; 214 static const size_t RegionSize; 215 static const size_t RegionSizeBytes; 216 217 // Mask for the bits in a size_t to get an offset within a region. 218 static const size_t RegionSizeOffsetMask; 219 // Mask for the bits in a pointer to get an offset within a region. 220 static const size_t RegionAddrOffsetMask; 221 // Mask for the bits in a pointer to get the address of the start of a region. 222 static const size_t RegionAddrMask; 223 224 static const size_t Log2BlockSize; 225 static const size_t BlockSize; 226 static const size_t BlockSizeBytes; 227 228 static const size_t BlockSizeOffsetMask; 229 static const size_t BlockAddrOffsetMask; 230 static const size_t BlockAddrMask; 231 232 static const size_t BlocksPerRegion; 233 static const size_t Log2BlocksPerRegion; 234 235 class RegionData 236 { 237 public: 238 // Destination address of the region. 239 HeapWord* destination() const { return _destination; } 240 241 // The first region containing data destined for this region. 242 size_t source_region() const { return _source_region; } 243 244 // The object (if any) starting in this region and ending in a different 245 // region that could not be updated during the main (parallel) compaction 246 // phase. This is different from _partial_obj_addr, which is an object that 247 // extends onto a source region. However, the two uses do not overlap in 248 // time, so the same field is used to save space. 249 HeapWord* deferred_obj_addr() const { return _partial_obj_addr; } 250 251 // The starting address of the partial object extending onto the region. 252 HeapWord* partial_obj_addr() const { return _partial_obj_addr; } 253 254 // Size of the partial object extending onto the region (words). 255 size_t partial_obj_size() const { return _partial_obj_size; } 256 257 // Size of live data that lies within this region due to objects that start 258 // in this region (words). This does not include the partial object 259 // extending onto the region (if any), or the part of an object that extends 260 // onto the next region (if any). 261 size_t live_obj_size() const { return _dc_and_los & los_mask; } 262 263 // Total live data that lies within the region (words). 264 size_t data_size() const { return partial_obj_size() + live_obj_size(); } 265 266 // The destination_count is the number of other regions to which data from 267 // this region will be copied. At the end of the summary phase, the valid 268 // values of destination_count are 269 // 270 // 0 - data from the region will be compacted completely into itself, or the 271 // region is empty. The region can be claimed and then filled. 272 // 1 - data from the region will be compacted into 1 other region; some 273 // data from the region may also be compacted into the region itself. 274 // 2 - data from the region will be copied to 2 other regions. 275 // 276 // During compaction as regions are emptied, the destination_count is 277 // decremented (atomically) and when it reaches 0, it can be claimed and 278 // then filled. 279 // 280 // A region is claimed for processing by atomically changing the 281 // destination_count to the claimed value (dc_claimed). After a region has 282 // been filled, the destination_count should be set to the completed value 283 // (dc_completed). 284 inline uint destination_count() const; 285 inline uint destination_count_raw() const; 286 287 // Whether the block table for this region has been filled. 288 inline bool blocks_filled() const; 289 290 // Number of times the block table was filled. 291 DEBUG_ONLY(inline size_t blocks_filled_count() const;) 292 293 // The location of the java heap data that corresponds to this region. 294 inline HeapWord* data_location() const; 295 296 // The highest address referenced by objects in this region. 297 inline HeapWord* highest_ref() const; 298 299 // Whether this region is available to be claimed, has been claimed, or has 300 // been completed. 301 // 302 // Minor subtlety: claimed() returns true if the region is marked 303 // completed(), which is desirable since a region must be claimed before it 304 // can be completed. 305 bool available() const { return _dc_and_los < dc_one; } 306 bool claimed() const { return _dc_and_los >= dc_claimed; } 307 bool completed() const { return _dc_and_los >= dc_completed; } 308 309 // These are not atomic. 310 void set_destination(HeapWord* addr) { _destination = addr; } 311 void set_source_region(size_t region) { _source_region = region; } 312 void set_deferred_obj_addr(HeapWord* addr) { _partial_obj_addr = addr; } 313 void set_partial_obj_addr(HeapWord* addr) { _partial_obj_addr = addr; } 314 void set_partial_obj_size(size_t words) { 315 _partial_obj_size = (region_sz_t) words; 316 } 317 inline void set_blocks_filled(); 318 319 inline void set_destination_count(uint count); 320 inline void set_live_obj_size(size_t words); 321 inline void set_data_location(HeapWord* addr); 322 inline void set_completed(); 323 inline bool claim_unsafe(); 324 325 // These are atomic. 326 inline void add_live_obj(size_t words); 327 inline void set_highest_ref(HeapWord* addr); 328 inline void decrement_destination_count(); 329 inline bool claim(); 330 331 private: 332 // The type used to represent object sizes within a region. 333 typedef uint region_sz_t; 334 335 // Constants for manipulating the _dc_and_los field, which holds both the 336 // destination count and live obj size. The live obj size lives at the 337 // least significant end so no masking is necessary when adding. 338 static const region_sz_t dc_shift; // Shift amount. 339 static const region_sz_t dc_mask; // Mask for destination count. 340 static const region_sz_t dc_one; // 1, shifted appropriately. 341 static const region_sz_t dc_claimed; // Region has been claimed. 342 static const region_sz_t dc_completed; // Region has been completed. 343 static const region_sz_t los_mask; // Mask for live obj size. 344 345 HeapWord* _destination; 346 size_t _source_region; 347 HeapWord* _partial_obj_addr; 348 region_sz_t _partial_obj_size; 349 region_sz_t volatile _dc_and_los; 350 bool _blocks_filled; 351 352 #ifdef ASSERT 353 size_t _blocks_filled_count; // Number of block table fills. 354 355 // These enable optimizations that are only partially implemented. Use 356 // debug builds to prevent the code fragments from breaking. 357 HeapWord* _data_location; 358 HeapWord* _highest_ref; 359 #endif // #ifdef ASSERT 360 361 #ifdef ASSERT 362 public: 363 uint _pushed; // 0 until region is pushed onto a stack 364 private: 365 #endif 366 }; 367 368 // "Blocks" allow shorter sections of the bitmap to be searched. Each Block 369 // holds an offset, which is the amount of live data in the Region to the left 370 // of the first live object that starts in the Block. 371 class BlockData 372 { 373 public: 374 typedef unsigned short int blk_ofs_t; 375 376 blk_ofs_t offset() const { return _offset; } 377 void set_offset(size_t val) { _offset = (blk_ofs_t)val; } 378 379 private: 380 blk_ofs_t _offset; 381 }; 382 383 public: 384 ParallelCompactData(); 385 bool initialize(MemRegion covered_region); 386 387 size_t region_count() const { return _region_count; } 388 size_t reserved_byte_size() const { return _reserved_byte_size; } 389 390 // Convert region indices to/from RegionData pointers. 391 inline RegionData* region(size_t region_idx) const; 392 inline size_t region(const RegionData* const region_ptr) const; 393 394 size_t block_count() const { return _block_count; } 395 inline BlockData* block(size_t block_idx) const; 396 inline size_t block(const BlockData* block_ptr) const; 397 398 void add_obj(HeapWord* addr, size_t len); 399 void add_obj(oop p, size_t len) { add_obj((HeapWord*)p, len); } 400 401 // Fill in the regions covering [beg, end) so that no data moves; i.e., the 402 // destination of region n is simply the start of region n. The argument beg 403 // must be region-aligned; end need not be. 404 void summarize_dense_prefix(HeapWord* beg, HeapWord* end); 405 406 HeapWord* summarize_split_space(size_t src_region, SplitInfo& split_info, 407 HeapWord* destination, HeapWord* target_end, 408 HeapWord** target_next); 409 bool summarize(SplitInfo& split_info, 410 HeapWord* source_beg, HeapWord* source_end, 411 HeapWord** source_next, 412 HeapWord* target_beg, HeapWord* target_end, 413 HeapWord** target_next); 414 415 void clear(); 416 void clear_range(size_t beg_region, size_t end_region); 417 void clear_range(HeapWord* beg, HeapWord* end) { 418 clear_range(addr_to_region_idx(beg), addr_to_region_idx(end)); 419 } 420 421 // Return the number of words between addr and the start of the region 422 // containing addr. 423 inline size_t region_offset(const HeapWord* addr) const; 424 425 // Convert addresses to/from a region index or region pointer. 426 inline size_t addr_to_region_idx(const HeapWord* addr) const; 427 inline RegionData* addr_to_region_ptr(const HeapWord* addr) const; 428 inline HeapWord* region_to_addr(size_t region) const; 429 inline HeapWord* region_to_addr(size_t region, size_t offset) const; 430 inline HeapWord* region_to_addr(const RegionData* region) const; 431 432 inline HeapWord* region_align_down(HeapWord* addr) const; 433 inline HeapWord* region_align_up(HeapWord* addr) const; 434 inline bool is_region_aligned(HeapWord* addr) const; 435 436 // Analogous to region_offset() for blocks. 437 size_t block_offset(const HeapWord* addr) const; 438 size_t addr_to_block_idx(const HeapWord* addr) const; 439 size_t addr_to_block_idx(const oop obj) const { 440 return addr_to_block_idx((HeapWord*) obj); 441 } 442 inline BlockData* addr_to_block_ptr(const HeapWord* addr) const; 443 inline HeapWord* block_to_addr(size_t block) const; 444 inline size_t region_to_block_idx(size_t region) const; 445 446 inline HeapWord* block_align_down(HeapWord* addr) const; 447 inline HeapWord* block_align_up(HeapWord* addr) const; 448 inline bool is_block_aligned(HeapWord* addr) const; 449 450 // Return the address one past the end of the partial object. 451 HeapWord* partial_obj_end(size_t region_idx) const; 452 453 // Return the location of the object after compaction. 454 HeapWord* calc_new_pointer(HeapWord* addr); 455 456 HeapWord* calc_new_pointer(oop p) { 457 return calc_new_pointer((HeapWord*) p); 458 } 459 460 #ifdef ASSERT 461 void verify_clear(const PSVirtualSpace* vspace); 462 void verify_clear(); 463 #endif // #ifdef ASSERT 464 465 private: 466 bool initialize_block_data(); 467 bool initialize_region_data(size_t region_size); 468 PSVirtualSpace* create_vspace(size_t count, size_t element_size); 469 470 private: 471 HeapWord* _region_start; 472 #ifdef ASSERT 473 HeapWord* _region_end; 474 #endif // #ifdef ASSERT 475 476 PSVirtualSpace* _region_vspace; 477 size_t _reserved_byte_size; 478 RegionData* _region_data; 479 size_t _region_count; 480 481 PSVirtualSpace* _block_vspace; 482 BlockData* _block_data; 483 size_t _block_count; 484 }; 485 486 inline uint 487 ParallelCompactData::RegionData::destination_count_raw() const 488 { 489 return _dc_and_los & dc_mask; 490 } 491 492 inline uint 493 ParallelCompactData::RegionData::destination_count() const 494 { 495 return destination_count_raw() >> dc_shift; 496 } 497 498 inline bool 499 ParallelCompactData::RegionData::blocks_filled() const 500 { 501 return _blocks_filled; 502 } 503 504 #ifdef ASSERT 505 inline size_t 506 ParallelCompactData::RegionData::blocks_filled_count() const 507 { 508 return _blocks_filled_count; 509 } 510 #endif // #ifdef ASSERT 511 512 inline void 513 ParallelCompactData::RegionData::set_blocks_filled() 514 { 515 _blocks_filled = true; 516 // Debug builds count the number of times the table was filled. 517 DEBUG_ONLY(Atomic::inc_ptr(&_blocks_filled_count)); 518 } 519 520 inline void 521 ParallelCompactData::RegionData::set_destination_count(uint count) 522 { 523 assert(count <= (dc_completed >> dc_shift), "count too large"); 524 const region_sz_t live_sz = (region_sz_t) live_obj_size(); 525 _dc_and_los = (count << dc_shift) | live_sz; 526 } 527 528 inline void ParallelCompactData::RegionData::set_live_obj_size(size_t words) 529 { 530 assert(words <= los_mask, "would overflow"); 531 _dc_and_los = destination_count_raw() | (region_sz_t)words; 532 } 533 534 inline void ParallelCompactData::RegionData::decrement_destination_count() 535 { 536 assert(_dc_and_los < dc_claimed, "already claimed"); 537 assert(_dc_and_los >= dc_one, "count would go negative"); 538 Atomic::add((int)dc_mask, (volatile int*)&_dc_and_los); 539 } 540 541 inline HeapWord* ParallelCompactData::RegionData::data_location() const 542 { 543 DEBUG_ONLY(return _data_location;) 544 NOT_DEBUG(return NULL;) 545 } 546 547 inline HeapWord* ParallelCompactData::RegionData::highest_ref() const 548 { 549 DEBUG_ONLY(return _highest_ref;) 550 NOT_DEBUG(return NULL;) 551 } 552 553 inline void ParallelCompactData::RegionData::set_data_location(HeapWord* addr) 554 { 555 DEBUG_ONLY(_data_location = addr;) 556 } 557 558 inline void ParallelCompactData::RegionData::set_completed() 559 { 560 assert(claimed(), "must be claimed first"); 561 _dc_and_los = dc_completed | (region_sz_t) live_obj_size(); 562 } 563 564 // MT-unsafe claiming of a region. Should only be used during single threaded 565 // execution. 566 inline bool ParallelCompactData::RegionData::claim_unsafe() 567 { 568 if (available()) { 569 _dc_and_los |= dc_claimed; 570 return true; 571 } 572 return false; 573 } 574 575 inline void ParallelCompactData::RegionData::add_live_obj(size_t words) 576 { 577 assert(words <= (size_t)los_mask - live_obj_size(), "overflow"); 578 Atomic::add((int) words, (volatile int*) &_dc_and_los); 579 } 580 581 inline void ParallelCompactData::RegionData::set_highest_ref(HeapWord* addr) 582 { 583 #ifdef ASSERT 584 HeapWord* tmp = _highest_ref; 585 while (addr > tmp) { 586 tmp = (HeapWord*)Atomic::cmpxchg_ptr(addr, &_highest_ref, tmp); 587 } 588 #endif // #ifdef ASSERT 589 } 590 591 inline bool ParallelCompactData::RegionData::claim() 592 { 593 const int los = (int) live_obj_size(); 594 const int old = Atomic::cmpxchg(dc_claimed | los, 595 (volatile int*) &_dc_and_los, los); 596 return old == los; 597 } 598 599 inline ParallelCompactData::RegionData* 600 ParallelCompactData::region(size_t region_idx) const 601 { 602 assert(region_idx <= region_count(), "bad arg"); 603 return _region_data + region_idx; 604 } 605 606 inline size_t 607 ParallelCompactData::region(const RegionData* const region_ptr) const 608 { 609 assert(region_ptr >= _region_data, "bad arg"); 610 assert(region_ptr <= _region_data + region_count(), "bad arg"); 611 return pointer_delta(region_ptr, _region_data, sizeof(RegionData)); 612 } 613 614 inline ParallelCompactData::BlockData* 615 ParallelCompactData::block(size_t n) const { 616 assert(n < block_count(), "bad arg"); 617 return _block_data + n; 618 } 619 620 inline size_t 621 ParallelCompactData::region_offset(const HeapWord* addr) const 622 { 623 assert(addr >= _region_start, "bad addr"); 624 assert(addr <= _region_end, "bad addr"); 625 return (size_t(addr) & RegionAddrOffsetMask) >> LogHeapWordSize; 626 } 627 628 inline size_t 629 ParallelCompactData::addr_to_region_idx(const HeapWord* addr) const 630 { 631 assert(addr >= _region_start, "bad addr"); 632 assert(addr <= _region_end, "bad addr"); 633 return pointer_delta(addr, _region_start) >> Log2RegionSize; 634 } 635 636 inline ParallelCompactData::RegionData* 637 ParallelCompactData::addr_to_region_ptr(const HeapWord* addr) const 638 { 639 return region(addr_to_region_idx(addr)); 640 } 641 642 inline HeapWord* 643 ParallelCompactData::region_to_addr(size_t region) const 644 { 645 assert(region <= _region_count, "region out of range"); 646 return _region_start + (region << Log2RegionSize); 647 } 648 649 inline HeapWord* 650 ParallelCompactData::region_to_addr(const RegionData* region) const 651 { 652 return region_to_addr(pointer_delta(region, _region_data, 653 sizeof(RegionData))); 654 } 655 656 inline HeapWord* 657 ParallelCompactData::region_to_addr(size_t region, size_t offset) const 658 { 659 assert(region <= _region_count, "region out of range"); 660 assert(offset < RegionSize, "offset too big"); // This may be too strict. 661 return region_to_addr(region) + offset; 662 } 663 664 inline HeapWord* 665 ParallelCompactData::region_align_down(HeapWord* addr) const 666 { 667 assert(addr >= _region_start, "bad addr"); 668 assert(addr < _region_end + RegionSize, "bad addr"); 669 return (HeapWord*)(size_t(addr) & RegionAddrMask); 670 } 671 672 inline HeapWord* 673 ParallelCompactData::region_align_up(HeapWord* addr) const 674 { 675 assert(addr >= _region_start, "bad addr"); 676 assert(addr <= _region_end, "bad addr"); 677 return region_align_down(addr + RegionSizeOffsetMask); 678 } 679 680 inline bool 681 ParallelCompactData::is_region_aligned(HeapWord* addr) const 682 { 683 return region_offset(addr) == 0; 684 } 685 686 inline size_t 687 ParallelCompactData::block_offset(const HeapWord* addr) const 688 { 689 assert(addr >= _region_start, "bad addr"); 690 assert(addr <= _region_end, "bad addr"); 691 return (size_t(addr) & BlockAddrOffsetMask) >> LogHeapWordSize; 692 } 693 694 inline size_t 695 ParallelCompactData::addr_to_block_idx(const HeapWord* addr) const 696 { 697 assert(addr >= _region_start, "bad addr"); 698 assert(addr <= _region_end, "bad addr"); 699 return pointer_delta(addr, _region_start) >> Log2BlockSize; 700 } 701 702 inline ParallelCompactData::BlockData* 703 ParallelCompactData::addr_to_block_ptr(const HeapWord* addr) const 704 { 705 return block(addr_to_block_idx(addr)); 706 } 707 708 inline HeapWord* 709 ParallelCompactData::block_to_addr(size_t block) const 710 { 711 assert(block < _block_count, "block out of range"); 712 return _region_start + (block << Log2BlockSize); 713 } 714 715 inline size_t 716 ParallelCompactData::region_to_block_idx(size_t region) const 717 { 718 return region << Log2BlocksPerRegion; 719 } 720 721 inline HeapWord* 722 ParallelCompactData::block_align_down(HeapWord* addr) const 723 { 724 assert(addr >= _region_start, "bad addr"); 725 assert(addr < _region_end + RegionSize, "bad addr"); 726 return (HeapWord*)(size_t(addr) & BlockAddrMask); 727 } 728 729 inline HeapWord* 730 ParallelCompactData::block_align_up(HeapWord* addr) const 731 { 732 assert(addr >= _region_start, "bad addr"); 733 assert(addr <= _region_end, "bad addr"); 734 return block_align_down(addr + BlockSizeOffsetMask); 735 } 736 737 inline bool 738 ParallelCompactData::is_block_aligned(HeapWord* addr) const 739 { 740 return block_offset(addr) == 0; 741 } 742 743 // Abstract closure for use with ParMarkBitMap::iterate(), which will invoke the 744 // do_addr() method. 745 // 746 // The closure is initialized with the number of heap words to process 747 // (words_remaining()), and becomes 'full' when it reaches 0. The do_addr() 748 // methods in subclasses should update the total as words are processed. Since 749 // only one subclass actually uses this mechanism to terminate iteration, the 750 // default initial value is > 0. The implementation is here and not in the 751 // single subclass that uses it to avoid making is_full() virtual, and thus 752 // adding a virtual call per live object. 753 754 class ParMarkBitMapClosure: public StackObj { 755 public: 756 typedef ParMarkBitMap::idx_t idx_t; 757 typedef ParMarkBitMap::IterationStatus IterationStatus; 758 759 public: 760 inline ParMarkBitMapClosure(ParMarkBitMap* mbm, ParCompactionManager* cm, 761 size_t words = max_uintx); 762 763 inline ParCompactionManager* compaction_manager() const; 764 inline ParMarkBitMap* bitmap() const; 765 inline size_t words_remaining() const; 766 inline bool is_full() const; 767 inline HeapWord* source() const; 768 769 inline void set_source(HeapWord* addr); 770 771 virtual IterationStatus do_addr(HeapWord* addr, size_t words) = 0; 772 773 protected: 774 inline void decrement_words_remaining(size_t words); 775 776 private: 777 ParMarkBitMap* const _bitmap; 778 ParCompactionManager* const _compaction_manager; 779 DEBUG_ONLY(const size_t _initial_words_remaining;) // Useful in debugger. 780 size_t _words_remaining; // Words left to copy. 781 782 protected: 783 HeapWord* _source; // Next addr that would be read. 784 }; 785 786 inline 787 ParMarkBitMapClosure::ParMarkBitMapClosure(ParMarkBitMap* bitmap, 788 ParCompactionManager* cm, 789 size_t words): 790 _bitmap(bitmap), _compaction_manager(cm) 791 #ifdef ASSERT 792 , _initial_words_remaining(words) 793 #endif 794 { 795 _words_remaining = words; 796 _source = NULL; 797 } 798 799 inline ParCompactionManager* ParMarkBitMapClosure::compaction_manager() const { 800 return _compaction_manager; 801 } 802 803 inline ParMarkBitMap* ParMarkBitMapClosure::bitmap() const { 804 return _bitmap; 805 } 806 807 inline size_t ParMarkBitMapClosure::words_remaining() const { 808 return _words_remaining; 809 } 810 811 inline bool ParMarkBitMapClosure::is_full() const { 812 return words_remaining() == 0; 813 } 814 815 inline HeapWord* ParMarkBitMapClosure::source() const { 816 return _source; 817 } 818 819 inline void ParMarkBitMapClosure::set_source(HeapWord* addr) { 820 _source = addr; 821 } 822 823 inline void ParMarkBitMapClosure::decrement_words_remaining(size_t words) { 824 assert(_words_remaining >= words, "processed too many words"); 825 _words_remaining -= words; 826 } 827 828 // The UseParallelOldGC collector is a stop-the-world garbage collector that 829 // does parts of the collection using parallel threads. The collection includes 830 // the tenured generation and the young generation. The permanent generation is 831 // collected at the same time as the other two generations but the permanent 832 // generation is collect by a single GC thread. The permanent generation is 833 // collected serially because of the requirement that during the processing of a 834 // klass AAA, any objects reference by AAA must already have been processed. 835 // This requirement is enforced by a left (lower address) to right (higher 836 // address) sliding compaction. 837 // 838 // There are four phases of the collection. 839 // 840 // - marking phase 841 // - summary phase 842 // - compacting phase 843 // - clean up phase 844 // 845 // Roughly speaking these phases correspond, respectively, to 846 // - mark all the live objects 847 // - calculate the destination of each object at the end of the collection 848 // - move the objects to their destination 849 // - update some references and reinitialize some variables 850 // 851 // These three phases are invoked in PSParallelCompact::invoke_no_policy(). The 852 // marking phase is implemented in PSParallelCompact::marking_phase() and does a 853 // complete marking of the heap. The summary phase is implemented in 854 // PSParallelCompact::summary_phase(). The move and update phase is implemented 855 // in PSParallelCompact::compact(). 856 // 857 // A space that is being collected is divided into regions and with each region 858 // is associated an object of type ParallelCompactData. Each region is of a 859 // fixed size and typically will contain more than 1 object and may have parts 860 // of objects at the front and back of the region. 861 // 862 // region -----+---------------------+---------- 863 // objects covered [ AAA )[ BBB )[ CCC )[ DDD ) 864 // 865 // The marking phase does a complete marking of all live objects in the heap. 866 // The marking also compiles the size of the data for all live objects covered 867 // by the region. This size includes the part of any live object spanning onto 868 // the region (part of AAA if it is live) from the front, all live objects 869 // contained in the region (BBB and/or CCC if they are live), and the part of 870 // any live objects covered by the region that extends off the region (part of 871 // DDD if it is live). The marking phase uses multiple GC threads and marking 872 // is done in a bit array of type ParMarkBitMap. The marking of the bit map is 873 // done atomically as is the accumulation of the size of the live objects 874 // covered by a region. 875 // 876 // The summary phase calculates the total live data to the left of each region 877 // XXX. Based on that total and the bottom of the space, it can calculate the 878 // starting location of the live data in XXX. The summary phase calculates for 879 // each region XXX quantities such as 880 // 881 // - the amount of live data at the beginning of a region from an object 882 // entering the region. 883 // - the location of the first live data on the region 884 // - a count of the number of regions receiving live data from XXX. 885 // 886 // See ParallelCompactData for precise details. The summary phase also 887 // calculates the dense prefix for the compaction. The dense prefix is a 888 // portion at the beginning of the space that is not moved. The objects in the 889 // dense prefix do need to have their object references updated. See method 890 // summarize_dense_prefix(). 891 // 892 // The summary phase is done using 1 GC thread. 893 // 894 // The compaction phase moves objects to their new location and updates all 895 // references in the object. 896 // 897 // A current exception is that objects that cross a region boundary are moved 898 // but do not have their references updated. References are not updated because 899 // it cannot easily be determined if the klass pointer KKK for the object AAA 900 // has been updated. KKK likely resides in a region to the left of the region 901 // containing AAA. These AAA's have there references updated at the end in a 902 // clean up phase. See the method PSParallelCompact::update_deferred_objects(). 903 // An alternate strategy is being investigated for this deferral of updating. 904 // 905 // Compaction is done on a region basis. A region that is ready to be filled is 906 // put on a ready list and GC threads take region off the list and fill them. A 907 // region is ready to be filled if it empty of live objects. Such a region may 908 // have been initially empty (only contained dead objects) or may have had all 909 // its live objects copied out already. A region that compacts into itself is 910 // also ready for filling. The ready list is initially filled with empty 911 // regions and regions compacting into themselves. There is always at least 1 912 // region that can be put on the ready list. The regions are atomically added 913 // and removed from the ready list. 914 915 class PSParallelCompact : AllStatic { 916 public: 917 // Convenient access to type names. 918 typedef ParMarkBitMap::idx_t idx_t; 919 typedef ParallelCompactData::RegionData RegionData; 920 typedef ParallelCompactData::BlockData BlockData; 921 922 typedef enum { 923 old_space_id, eden_space_id, 924 from_space_id, to_space_id, last_space_id 925 } SpaceId; 926 927 public: 928 // Inline closure decls 929 // 930 class IsAliveClosure: public BoolObjectClosure { 931 public: 932 virtual bool do_object_b(oop p); 933 }; 934 935 class KeepAliveClosure: public OopClosure { 936 private: 937 ParCompactionManager* _compaction_manager; 938 protected: 939 template <class T> inline void do_oop_work(T* p); 940 public: 941 KeepAliveClosure(ParCompactionManager* cm) : _compaction_manager(cm) { } 942 virtual void do_oop(oop* p); 943 virtual void do_oop(narrowOop* p); 944 }; 945 946 class FollowStackClosure: public VoidClosure { 947 private: 948 ParCompactionManager* _compaction_manager; 949 public: 950 FollowStackClosure(ParCompactionManager* cm) : _compaction_manager(cm) { } 951 virtual void do_void(); 952 }; 953 954 class AdjustPointerClosure: public ExtendedOopClosure { 955 public: 956 template <typename T> void do_oop_nv(T* p); 957 virtual void do_oop(oop* p); 958 virtual void do_oop(narrowOop* p); 959 960 // do not walk from thread stacks to the code cache on this phase 961 virtual void do_code_blob(CodeBlob* cb) const { } 962 963 // This closure provides its own oop verification code. 964 debug_only(virtual bool should_verify_oops() { return false; }) 965 }; 966 967 class AdjustKlassClosure : public KlassClosure { 968 public: 969 void do_klass(Klass* klass); 970 }; 971 972 friend class KeepAliveClosure; 973 friend class FollowStackClosure; 974 friend class AdjustPointerClosure; 975 friend class AdjustKlassClosure; 976 friend class FollowKlassClosure; 977 friend class InstanceClassLoaderKlass; 978 friend class RefProcTaskProxy; 979 980 private: 981 static STWGCTimer _gc_timer; 982 static ParallelOldTracer _gc_tracer; 983 static elapsedTimer _accumulated_time; 984 static unsigned int _total_invocations; 985 static unsigned int _maximum_compaction_gc_num; 986 static jlong _time_of_last_gc; // ms 987 static CollectorCounters* _counters; 988 static ParMarkBitMap _mark_bitmap; 989 static ParallelCompactData _summary_data; 990 static IsAliveClosure _is_alive_closure; 991 static SpaceInfo _space_info[last_space_id]; 992 static bool _print_phases; 993 static AdjustPointerClosure _adjust_pointer_closure; 994 static AdjustKlassClosure _adjust_klass_closure; 995 996 // Reference processing (used in ...follow_contents) 997 static ReferenceProcessor* _ref_processor; 998 999 // Updated location of intArrayKlassObj. 1000 static Klass* _updated_int_array_klass_obj; 1001 1002 // Values computed at initialization and used by dead_wood_limiter(). 1003 static double _dwl_mean; 1004 static double _dwl_std_dev; 1005 static double _dwl_first_term; 1006 static double _dwl_adjustment; 1007 #ifdef ASSERT 1008 static bool _dwl_initialized; 1009 #endif // #ifdef ASSERT 1010 1011 1012 public: 1013 static ParallelOldTracer* gc_tracer() { return &_gc_tracer; } 1014 1015 private: 1016 1017 static void initialize_space_info(); 1018 1019 // Return true if details about individual phases should be printed. 1020 static inline bool print_phases(); 1021 1022 // Clear the marking bitmap and summary data that cover the specified space. 1023 static void clear_data_covering_space(SpaceId id); 1024 1025 static void pre_compact(PreGCValues* pre_gc_values); 1026 static void post_compact(); 1027 1028 // Mark live objects 1029 static void marking_phase(ParCompactionManager* cm, 1030 bool maximum_heap_compaction, 1031 ParallelOldTracer *gc_tracer); 1032 1033 // Compute the dense prefix for the designated space. This is an experimental 1034 // implementation currently not used in production. 1035 static HeapWord* compute_dense_prefix_via_density(const SpaceId id, 1036 bool maximum_compaction); 1037 1038 // Methods used to compute the dense prefix. 1039 1040 // Compute the value of the normal distribution at x = density. The mean and 1041 // standard deviation are values saved by initialize_dead_wood_limiter(). 1042 static inline double normal_distribution(double density); 1043 1044 // Initialize the static vars used by dead_wood_limiter(). 1045 static void initialize_dead_wood_limiter(); 1046 1047 // Return the percentage of space that can be treated as "dead wood" (i.e., 1048 // not reclaimed). 1049 static double dead_wood_limiter(double density, size_t min_percent); 1050 1051 // Find the first (left-most) region in the range [beg, end) that has at least 1052 // dead_words of dead space to the left. The argument beg must be the first 1053 // region in the space that is not completely live. 1054 static RegionData* dead_wood_limit_region(const RegionData* beg, 1055 const RegionData* end, 1056 size_t dead_words); 1057 1058 // Return a pointer to the first region in the range [beg, end) that is not 1059 // completely full. 1060 static RegionData* first_dead_space_region(const RegionData* beg, 1061 const RegionData* end); 1062 1063 // Return a value indicating the benefit or 'yield' if the compacted region 1064 // were to start (or equivalently if the dense prefix were to end) at the 1065 // candidate region. Higher values are better. 1066 // 1067 // The value is based on the amount of space reclaimed vs. the costs of (a) 1068 // updating references in the dense prefix plus (b) copying objects and 1069 // updating references in the compacted region. 1070 static inline double reclaimed_ratio(const RegionData* const candidate, 1071 HeapWord* const bottom, 1072 HeapWord* const top, 1073 HeapWord* const new_top); 1074 1075 // Compute the dense prefix for the designated space. 1076 static HeapWord* compute_dense_prefix(const SpaceId id, 1077 bool maximum_compaction); 1078 1079 // Return true if dead space crosses onto the specified Region; bit must be 1080 // the bit index corresponding to the first word of the Region. 1081 static inline bool dead_space_crosses_boundary(const RegionData* region, 1082 idx_t bit); 1083 1084 // Summary phase utility routine to fill dead space (if any) at the dense 1085 // prefix boundary. Should only be called if the the dense prefix is 1086 // non-empty. 1087 static void fill_dense_prefix_end(SpaceId id); 1088 1089 // Clear the summary data source_region field for the specified addresses. 1090 static void clear_source_region(HeapWord* beg_addr, HeapWord* end_addr); 1091 1092 #ifndef PRODUCT 1093 // Routines to provoke splitting a young gen space (ParallelOldGCSplitALot). 1094 1095 // Fill the region [start, start + words) with live object(s). Only usable 1096 // for the old and permanent generations. 1097 static void fill_with_live_objects(SpaceId id, HeapWord* const start, 1098 size_t words); 1099 // Include the new objects in the summary data. 1100 static void summarize_new_objects(SpaceId id, HeapWord* start); 1101 1102 // Add live objects to a survivor space since it's rare that both survivors 1103 // are non-empty. 1104 static void provoke_split_fill_survivor(SpaceId id); 1105 1106 // Add live objects and/or choose the dense prefix to provoke splitting. 1107 static void provoke_split(bool & maximum_compaction); 1108 #endif 1109 1110 static void summarize_spaces_quick(); 1111 static void summarize_space(SpaceId id, bool maximum_compaction); 1112 static void summary_phase(ParCompactionManager* cm, bool maximum_compaction); 1113 1114 // Adjust addresses in roots. Does not adjust addresses in heap. 1115 static void adjust_roots(); 1116 1117 DEBUG_ONLY(static void write_block_fill_histogram(outputStream* const out);) 1118 1119 // Move objects to new locations. 1120 static void compact_perm(ParCompactionManager* cm); 1121 static void compact(); 1122 1123 // Add available regions to the stack and draining tasks to the task queue. 1124 static void enqueue_region_draining_tasks(GCTaskQueue* q, 1125 uint parallel_gc_threads); 1126 1127 // Add dense prefix update tasks to the task queue. 1128 static void enqueue_dense_prefix_tasks(GCTaskQueue* q, 1129 uint parallel_gc_threads); 1130 1131 // Add region stealing tasks to the task queue. 1132 static void enqueue_region_stealing_tasks( 1133 GCTaskQueue* q, 1134 ParallelTaskTerminator* terminator_ptr, 1135 uint parallel_gc_threads); 1136 1137 // If objects are left in eden after a collection, try to move the boundary 1138 // and absorb them into the old gen. Returns true if eden was emptied. 1139 static bool absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy, 1140 PSYoungGen* young_gen, 1141 PSOldGen* old_gen); 1142 1143 // Reset time since last full gc 1144 static void reset_millis_since_last_gc(); 1145 1146 public: 1147 class MarkAndPushClosure: public ExtendedOopClosure { 1148 private: 1149 ParCompactionManager* _compaction_manager; 1150 public: 1151 MarkAndPushClosure(ParCompactionManager* cm) : _compaction_manager(cm) { } 1152 1153 template <typename T> void do_oop_nv(T* p); 1154 virtual void do_oop(oop* p); 1155 virtual void do_oop(narrowOop* p); 1156 1157 // This closure provides its own oop verification code. 1158 debug_only(virtual bool should_verify_oops() { return false; }) 1159 }; 1160 1161 // The one and only place to start following the classes. 1162 // Should only be applied to the ClassLoaderData klasses list. 1163 class FollowKlassClosure : public KlassClosure { 1164 private: 1165 MarkAndPushClosure* _mark_and_push_closure; 1166 public: 1167 FollowKlassClosure(MarkAndPushClosure* mark_and_push_closure) : 1168 _mark_and_push_closure(mark_and_push_closure) { } 1169 void do_klass(Klass* klass); 1170 }; 1171 1172 PSParallelCompact(); 1173 1174 // Convenient accessor for Universe::heap(). 1175 static ParallelScavengeHeap* gc_heap() { 1176 return (ParallelScavengeHeap*)Universe::heap(); 1177 } 1178 1179 static void invoke(bool maximum_heap_compaction); 1180 static bool invoke_no_policy(bool maximum_heap_compaction); 1181 1182 static void post_initialize(); 1183 // Perform initialization for PSParallelCompact that requires 1184 // allocations. This should be called during the VM initialization 1185 // at a pointer where it would be appropriate to return a JNI_ENOMEM 1186 // in the event of a failure. 1187 static bool initialize(); 1188 1189 // Closure accessors 1190 static PSParallelCompact::AdjustPointerClosure* adjust_pointer_closure() { 1191 return &_adjust_pointer_closure; 1192 } 1193 static KlassClosure* adjust_klass_closure() { return (KlassClosure*)&_adjust_klass_closure; } 1194 static BoolObjectClosure* is_alive_closure() { return (BoolObjectClosure*)&_is_alive_closure; } 1195 1196 // Public accessors 1197 static elapsedTimer* accumulated_time() { return &_accumulated_time; } 1198 static unsigned int total_invocations() { return _total_invocations; } 1199 static CollectorCounters* counters() { return _counters; } 1200 1201 // Used to add tasks 1202 static GCTaskManager* const gc_task_manager(); 1203 static Klass* updated_int_array_klass_obj() { 1204 return _updated_int_array_klass_obj; 1205 } 1206 1207 // Marking support 1208 static inline bool mark_obj(oop obj); 1209 static inline bool is_marked(oop obj); 1210 // Check mark and maybe push on marking stack 1211 template <class T> static inline void mark_and_push(ParCompactionManager* cm, 1212 T* p); 1213 template <class T> static inline void adjust_pointer(T* p); 1214 1215 static inline void follow_klass(ParCompactionManager* cm, Klass* klass); 1216 1217 static void follow_class_loader(ParCompactionManager* cm, 1218 ClassLoaderData* klass); 1219 1220 // Compaction support. 1221 // Return true if p is in the range [beg_addr, end_addr). 1222 static inline bool is_in(HeapWord* p, HeapWord* beg_addr, HeapWord* end_addr); 1223 static inline bool is_in(oop* p, HeapWord* beg_addr, HeapWord* end_addr); 1224 1225 // Convenience wrappers for per-space data kept in _space_info. 1226 static inline MutableSpace* space(SpaceId space_id); 1227 static inline HeapWord* new_top(SpaceId space_id); 1228 static inline HeapWord* dense_prefix(SpaceId space_id); 1229 static inline ObjectStartArray* start_array(SpaceId space_id); 1230 1231 // Move and update the live objects in the specified space. 1232 static void move_and_update(ParCompactionManager* cm, SpaceId space_id); 1233 1234 // Process the end of the given region range in the dense prefix. 1235 // This includes saving any object not updated. 1236 static void dense_prefix_regions_epilogue(ParCompactionManager* cm, 1237 size_t region_start_index, 1238 size_t region_end_index, 1239 idx_t exiting_object_offset, 1240 idx_t region_offset_start, 1241 idx_t region_offset_end); 1242 1243 // Update a region in the dense prefix. For each live object 1244 // in the region, update it's interior references. For each 1245 // dead object, fill it with deadwood. Dead space at the end 1246 // of a region range will be filled to the start of the next 1247 // live object regardless of the region_index_end. None of the 1248 // objects in the dense prefix move and dead space is dead 1249 // (holds only dead objects that don't need any processing), so 1250 // dead space can be filled in any order. 1251 static void update_and_deadwood_in_dense_prefix(ParCompactionManager* cm, 1252 SpaceId space_id, 1253 size_t region_index_start, 1254 size_t region_index_end); 1255 1256 // Return the address of the count + 1st live word in the range [beg, end). 1257 static HeapWord* skip_live_words(HeapWord* beg, HeapWord* end, size_t count); 1258 1259 // Return the address of the word to be copied to dest_addr, which must be 1260 // aligned to a region boundary. 1261 static HeapWord* first_src_addr(HeapWord* const dest_addr, 1262 SpaceId src_space_id, 1263 size_t src_region_idx); 1264 1265 // Determine the next source region, set closure.source() to the start of the 1266 // new region return the region index. Parameter end_addr is the address one 1267 // beyond the end of source range just processed. If necessary, switch to a 1268 // new source space and set src_space_id (in-out parameter) and src_space_top 1269 // (out parameter) accordingly. 1270 static size_t next_src_region(MoveAndUpdateClosure& closure, 1271 SpaceId& src_space_id, 1272 HeapWord*& src_space_top, 1273 HeapWord* end_addr); 1274 1275 // Decrement the destination count for each non-empty source region in the 1276 // range [beg_region, region(region_align_up(end_addr))). If the destination 1277 // count for a region goes to 0 and it needs to be filled, enqueue it. 1278 static void decrement_destination_counts(ParCompactionManager* cm, 1279 SpaceId src_space_id, 1280 size_t beg_region, 1281 HeapWord* end_addr); 1282 1283 // Fill a region, copying objects from one or more source regions. 1284 static void fill_region(ParCompactionManager* cm, size_t region_idx); 1285 static void fill_and_update_region(ParCompactionManager* cm, size_t region) { 1286 fill_region(cm, region); 1287 } 1288 1289 // Fill in the block table for the specified region. 1290 static void fill_blocks(size_t region_idx); 1291 1292 // Update the deferred objects in the space. 1293 static void update_deferred_objects(ParCompactionManager* cm, SpaceId id); 1294 1295 static ParMarkBitMap* mark_bitmap() { return &_mark_bitmap; } 1296 static ParallelCompactData& summary_data() { return _summary_data; } 1297 1298 // Reference Processing 1299 static ReferenceProcessor* const ref_processor() { return _ref_processor; } 1300 1301 static STWGCTimer* gc_timer() { return &_gc_timer; } 1302 1303 // Return the SpaceId for the given address. 1304 static SpaceId space_id(HeapWord* addr); 1305 1306 // Time since last full gc (in milliseconds). 1307 static jlong millis_since_last_gc(); 1308 1309 static void print_on_error(outputStream* st); 1310 1311 #ifndef PRODUCT 1312 // Debugging support. 1313 static const char* space_names[last_space_id]; 1314 static void print_region_ranges(); 1315 static void print_dense_prefix_stats(const char* const algorithm, 1316 const SpaceId id, 1317 const bool maximum_compaction, 1318 HeapWord* const addr); 1319 static void summary_phase_msg(SpaceId dst_space_id, 1320 HeapWord* dst_beg, HeapWord* dst_end, 1321 SpaceId src_space_id, 1322 HeapWord* src_beg, HeapWord* src_end); 1323 #endif // #ifndef PRODUCT 1324 1325 #ifdef ASSERT 1326 // Sanity check the new location of a word in the heap. 1327 static inline void check_new_location(HeapWord* old_addr, HeapWord* new_addr); 1328 // Verify that all the regions have been emptied. 1329 static void verify_complete(SpaceId space_id); 1330 #endif // #ifdef ASSERT 1331 }; 1332 1333 inline bool PSParallelCompact::mark_obj(oop obj) { 1334 const int obj_size = obj->size(); 1335 if (mark_bitmap()->mark_obj(obj, obj_size)) { 1336 _summary_data.add_obj(obj, obj_size); 1337 return true; 1338 } else { 1339 return false; 1340 } 1341 } 1342 1343 inline bool PSParallelCompact::is_marked(oop obj) { 1344 return mark_bitmap()->is_marked(obj); 1345 } 1346 1347 template <class T> 1348 inline void PSParallelCompact::KeepAliveClosure::do_oop_work(T* p) { 1349 mark_and_push(_compaction_manager, p); 1350 } 1351 1352 inline bool PSParallelCompact::print_phases() { 1353 return _print_phases; 1354 } 1355 1356 inline double PSParallelCompact::normal_distribution(double density) { 1357 assert(_dwl_initialized, "uninitialized"); 1358 const double squared_term = (density - _dwl_mean) / _dwl_std_dev; 1359 return _dwl_first_term * exp(-0.5 * squared_term * squared_term); 1360 } 1361 1362 inline bool 1363 PSParallelCompact::dead_space_crosses_boundary(const RegionData* region, 1364 idx_t bit) 1365 { 1366 assert(bit > 0, "cannot call this for the first bit/region"); 1367 assert(_summary_data.region_to_addr(region) == _mark_bitmap.bit_to_addr(bit), 1368 "sanity check"); 1369 1370 // Dead space crosses the boundary if (1) a partial object does not extend 1371 // onto the region, (2) an object does not start at the beginning of the 1372 // region, and (3) an object does not end at the end of the prior region. 1373 return region->partial_obj_size() == 0 && 1374 !_mark_bitmap.is_obj_beg(bit) && 1375 !_mark_bitmap.is_obj_end(bit - 1); 1376 } 1377 1378 inline bool 1379 PSParallelCompact::is_in(HeapWord* p, HeapWord* beg_addr, HeapWord* end_addr) { 1380 return p >= beg_addr && p < end_addr; 1381 } 1382 1383 inline bool 1384 PSParallelCompact::is_in(oop* p, HeapWord* beg_addr, HeapWord* end_addr) { 1385 return is_in((HeapWord*)p, beg_addr, end_addr); 1386 } 1387 1388 inline MutableSpace* PSParallelCompact::space(SpaceId id) { 1389 assert(id < last_space_id, "id out of range"); 1390 return _space_info[id].space(); 1391 } 1392 1393 inline HeapWord* PSParallelCompact::new_top(SpaceId id) { 1394 assert(id < last_space_id, "id out of range"); 1395 return _space_info[id].new_top(); 1396 } 1397 1398 inline HeapWord* PSParallelCompact::dense_prefix(SpaceId id) { 1399 assert(id < last_space_id, "id out of range"); 1400 return _space_info[id].dense_prefix(); 1401 } 1402 1403 inline ObjectStartArray* PSParallelCompact::start_array(SpaceId id) { 1404 assert(id < last_space_id, "id out of range"); 1405 return _space_info[id].start_array(); 1406 } 1407 1408 #ifdef ASSERT 1409 inline void 1410 PSParallelCompact::check_new_location(HeapWord* old_addr, HeapWord* new_addr) 1411 { 1412 assert(old_addr >= new_addr || space_id(old_addr) != space_id(new_addr), 1413 "must move left or to a different space"); 1414 assert(is_object_aligned((intptr_t)old_addr) && is_object_aligned((intptr_t)new_addr), 1415 "checking alignment"); 1416 } 1417 #endif // ASSERT 1418 1419 class MoveAndUpdateClosure: public ParMarkBitMapClosure { 1420 public: 1421 inline MoveAndUpdateClosure(ParMarkBitMap* bitmap, ParCompactionManager* cm, 1422 ObjectStartArray* start_array, 1423 HeapWord* destination, size_t words); 1424 1425 // Accessors. 1426 HeapWord* destination() const { return _destination; } 1427 1428 // If the object will fit (size <= words_remaining()), copy it to the current 1429 // destination, update the interior oops and the start array and return either 1430 // full (if the closure is full) or incomplete. If the object will not fit, 1431 // return would_overflow. 1432 virtual IterationStatus do_addr(HeapWord* addr, size_t size); 1433 1434 // Copy enough words to fill this closure, starting at source(). Interior 1435 // oops and the start array are not updated. Return full. 1436 IterationStatus copy_until_full(); 1437 1438 // Copy enough words to fill this closure or to the end of an object, 1439 // whichever is smaller, starting at source(). Interior oops and the start 1440 // array are not updated. 1441 void copy_partial_obj(); 1442 1443 protected: 1444 // Update variables to indicate that word_count words were processed. 1445 inline void update_state(size_t word_count); 1446 1447 protected: 1448 ObjectStartArray* const _start_array; 1449 HeapWord* _destination; // Next addr to be written. 1450 }; 1451 1452 inline 1453 MoveAndUpdateClosure::MoveAndUpdateClosure(ParMarkBitMap* bitmap, 1454 ParCompactionManager* cm, 1455 ObjectStartArray* start_array, 1456 HeapWord* destination, 1457 size_t words) : 1458 ParMarkBitMapClosure(bitmap, cm, words), _start_array(start_array) 1459 { 1460 _destination = destination; 1461 } 1462 1463 inline void MoveAndUpdateClosure::update_state(size_t words) 1464 { 1465 decrement_words_remaining(words); 1466 _source += words; 1467 _destination += words; 1468 } 1469 1470 class UpdateOnlyClosure: public ParMarkBitMapClosure { 1471 private: 1472 const PSParallelCompact::SpaceId _space_id; 1473 ObjectStartArray* const _start_array; 1474 1475 public: 1476 UpdateOnlyClosure(ParMarkBitMap* mbm, 1477 ParCompactionManager* cm, 1478 PSParallelCompact::SpaceId space_id); 1479 1480 // Update the object. 1481 virtual IterationStatus do_addr(HeapWord* addr, size_t words); 1482 1483 inline void do_addr(HeapWord* addr); 1484 }; 1485 1486 class FillClosure: public ParMarkBitMapClosure 1487 { 1488 public: 1489 FillClosure(ParCompactionManager* cm, PSParallelCompact::SpaceId space_id) : 1490 ParMarkBitMapClosure(PSParallelCompact::mark_bitmap(), cm), 1491 _start_array(PSParallelCompact::start_array(space_id)) 1492 { 1493 assert(space_id == PSParallelCompact::old_space_id, 1494 "cannot use FillClosure in the young gen"); 1495 } 1496 1497 virtual IterationStatus do_addr(HeapWord* addr, size_t size) { 1498 CollectedHeap::fill_with_objects(addr, size); 1499 HeapWord* const end = addr + size; 1500 do { 1501 _start_array->allocate_block(addr); 1502 addr += oop(addr)->size(); 1503 } while (addr < end); 1504 return ParMarkBitMap::incomplete; 1505 } 1506 1507 private: 1508 ObjectStartArray* const _start_array; 1509 }; 1510 1511 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSPARALLELCOMPACT_HPP