Tue, 07 Oct 2008 11:01:35 -0700
Merge
1 /*
2 * Copyright 2005-2008 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 class ParallelScavengeHeap;
26 class PSAdaptiveSizePolicy;
27 class PSYoungGen;
28 class PSOldGen;
29 class PSPermGen;
30 class ParCompactionManager;
31 class ParallelTaskTerminator;
32 class PSParallelCompact;
33 class GCTaskManager;
34 class GCTaskQueue;
35 class PreGCValues;
36 class MoveAndUpdateClosure;
37 class RefProcTaskExecutor;
39 class SpaceInfo
40 {
41 public:
42 MutableSpace* space() const { return _space; }
44 // Where the free space will start after the collection. Valid only after the
45 // summary phase completes.
46 HeapWord* new_top() const { return _new_top; }
48 // Allows new_top to be set.
49 HeapWord** new_top_addr() { return &_new_top; }
51 // Where the smallest allowable dense prefix ends (used only for perm gen).
52 HeapWord* min_dense_prefix() const { return _min_dense_prefix; }
54 // Where the dense prefix ends, or the compacted region begins.
55 HeapWord* dense_prefix() const { return _dense_prefix; }
57 // The start array for the (generation containing the) space, or NULL if there
58 // is no start array.
59 ObjectStartArray* start_array() const { return _start_array; }
61 void set_space(MutableSpace* s) { _space = s; }
62 void set_new_top(HeapWord* addr) { _new_top = addr; }
63 void set_min_dense_prefix(HeapWord* addr) { _min_dense_prefix = addr; }
64 void set_dense_prefix(HeapWord* addr) { _dense_prefix = addr; }
65 void set_start_array(ObjectStartArray* s) { _start_array = s; }
67 private:
68 MutableSpace* _space;
69 HeapWord* _new_top;
70 HeapWord* _min_dense_prefix;
71 HeapWord* _dense_prefix;
72 ObjectStartArray* _start_array;
73 };
75 class ParallelCompactData
76 {
77 public:
78 // Sizes are in HeapWords, unless indicated otherwise.
79 static const size_t Log2RegionSize;
80 static const size_t RegionSize;
81 static const size_t RegionSizeBytes;
83 // Mask for the bits in a size_t to get an offset within a region.
84 static const size_t RegionSizeOffsetMask;
85 // Mask for the bits in a pointer to get an offset within a region.
86 static const size_t RegionAddrOffsetMask;
87 // Mask for the bits in a pointer to get the address of the start of a region.
88 static const size_t RegionAddrMask;
90 class RegionData
91 {
92 public:
93 // Destination address of the region.
94 HeapWord* destination() const { return _destination; }
96 // The first region containing data destined for this region.
97 size_t source_region() const { return _source_region; }
99 // The object (if any) starting in this region and ending in a different
100 // region that could not be updated during the main (parallel) compaction
101 // phase. This is different from _partial_obj_addr, which is an object that
102 // extends onto a source region. However, the two uses do not overlap in
103 // time, so the same field is used to save space.
104 HeapWord* deferred_obj_addr() const { return _partial_obj_addr; }
106 // The starting address of the partial object extending onto the region.
107 HeapWord* partial_obj_addr() const { return _partial_obj_addr; }
109 // Size of the partial object extending onto the region (words).
110 size_t partial_obj_size() const { return _partial_obj_size; }
112 // Size of live data that lies within this region due to objects that start
113 // in this region (words). This does not include the partial object
114 // extending onto the region (if any), or the part of an object that extends
115 // onto the next region (if any).
116 size_t live_obj_size() const { return _dc_and_los & los_mask; }
118 // Total live data that lies within the region (words).
119 size_t data_size() const { return partial_obj_size() + live_obj_size(); }
121 // The destination_count is the number of other regions to which data from
122 // this region will be copied. At the end of the summary phase, the valid
123 // values of destination_count are
124 //
125 // 0 - data from the region will be compacted completely into itself, or the
126 // region is empty. The region can be claimed and then filled.
127 // 1 - data from the region will be compacted into 1 other region; some
128 // data from the region may also be compacted into the region itself.
129 // 2 - data from the region will be copied to 2 other regions.
130 //
131 // During compaction as regions are emptied, the destination_count is
132 // decremented (atomically) and when it reaches 0, it can be claimed and
133 // then filled.
134 //
135 // A region is claimed for processing by atomically changing the
136 // destination_count to the claimed value (dc_claimed). After a region has
137 // been filled, the destination_count should be set to the completed value
138 // (dc_completed).
139 inline uint destination_count() const;
140 inline uint destination_count_raw() const;
142 // The location of the java heap data that corresponds to this region.
143 inline HeapWord* data_location() const;
145 // The highest address referenced by objects in this region.
146 inline HeapWord* highest_ref() const;
148 // Whether this region is available to be claimed, has been claimed, or has
149 // been completed.
150 //
151 // Minor subtlety: claimed() returns true if the region is marked
152 // completed(), which is desirable since a region must be claimed before it
153 // can be completed.
154 bool available() const { return _dc_and_los < dc_one; }
155 bool claimed() const { return _dc_and_los >= dc_claimed; }
156 bool completed() const { return _dc_and_los >= dc_completed; }
158 // These are not atomic.
159 void set_destination(HeapWord* addr) { _destination = addr; }
160 void set_source_region(size_t region) { _source_region = region; }
161 void set_deferred_obj_addr(HeapWord* addr) { _partial_obj_addr = addr; }
162 void set_partial_obj_addr(HeapWord* addr) { _partial_obj_addr = addr; }
163 void set_partial_obj_size(size_t words) {
164 _partial_obj_size = (region_sz_t) words;
165 }
167 inline void set_destination_count(uint count);
168 inline void set_live_obj_size(size_t words);
169 inline void set_data_location(HeapWord* addr);
170 inline void set_completed();
171 inline bool claim_unsafe();
173 // These are atomic.
174 inline void add_live_obj(size_t words);
175 inline void set_highest_ref(HeapWord* addr);
176 inline void decrement_destination_count();
177 inline bool claim();
179 private:
180 // The type used to represent object sizes within a region.
181 typedef uint region_sz_t;
183 // Constants for manipulating the _dc_and_los field, which holds both the
184 // destination count and live obj size. The live obj size lives at the
185 // least significant end so no masking is necessary when adding.
186 static const region_sz_t dc_shift; // Shift amount.
187 static const region_sz_t dc_mask; // Mask for destination count.
188 static const region_sz_t dc_one; // 1, shifted appropriately.
189 static const region_sz_t dc_claimed; // Region has been claimed.
190 static const region_sz_t dc_completed; // Region has been completed.
191 static const region_sz_t los_mask; // Mask for live obj size.
193 HeapWord* _destination;
194 size_t _source_region;
195 HeapWord* _partial_obj_addr;
196 region_sz_t _partial_obj_size;
197 region_sz_t volatile _dc_and_los;
198 #ifdef ASSERT
199 // These enable optimizations that are only partially implemented. Use
200 // debug builds to prevent the code fragments from breaking.
201 HeapWord* _data_location;
202 HeapWord* _highest_ref;
203 #endif // #ifdef ASSERT
205 #ifdef ASSERT
206 public:
207 uint _pushed; // 0 until region is pushed onto a worker's stack
208 private:
209 #endif
210 };
212 public:
213 ParallelCompactData();
214 bool initialize(MemRegion covered_region);
216 size_t region_count() const { return _region_count; }
218 // Convert region indices to/from RegionData pointers.
219 inline RegionData* region(size_t region_idx) const;
220 inline size_t region(const RegionData* const region_ptr) const;
222 // Returns true if the given address is contained within the region
223 bool region_contains(size_t region_index, HeapWord* addr);
225 void add_obj(HeapWord* addr, size_t len);
226 void add_obj(oop p, size_t len) { add_obj((HeapWord*)p, len); }
228 // Fill in the regions covering [beg, end) so that no data moves; i.e., the
229 // destination of region n is simply the start of region n. The argument beg
230 // must be region-aligned; end need not be.
231 void summarize_dense_prefix(HeapWord* beg, HeapWord* end);
233 bool summarize(HeapWord* target_beg, HeapWord* target_end,
234 HeapWord* source_beg, HeapWord* source_end,
235 HeapWord** target_next, HeapWord** source_next = 0);
237 void clear();
238 void clear_range(size_t beg_region, size_t end_region);
239 void clear_range(HeapWord* beg, HeapWord* end) {
240 clear_range(addr_to_region_idx(beg), addr_to_region_idx(end));
241 }
243 // Return the number of words between addr and the start of the region
244 // containing addr.
245 inline size_t region_offset(const HeapWord* addr) const;
247 // Convert addresses to/from a region index or region pointer.
248 inline size_t addr_to_region_idx(const HeapWord* addr) const;
249 inline RegionData* addr_to_region_ptr(const HeapWord* addr) const;
250 inline HeapWord* region_to_addr(size_t region) const;
251 inline HeapWord* region_to_addr(size_t region, size_t offset) const;
252 inline HeapWord* region_to_addr(const RegionData* region) const;
254 inline HeapWord* region_align_down(HeapWord* addr) const;
255 inline HeapWord* region_align_up(HeapWord* addr) const;
256 inline bool is_region_aligned(HeapWord* addr) const;
258 // Return the address one past the end of the partial object.
259 HeapWord* partial_obj_end(size_t region_idx) const;
261 // Return the new location of the object p after the
262 // the compaction.
263 HeapWord* calc_new_pointer(HeapWord* addr);
265 HeapWord* calc_new_pointer(oop p) {
266 return calc_new_pointer((HeapWord*) p);
267 }
269 // Return the updated address for the given klass
270 klassOop calc_new_klass(klassOop);
272 #ifdef ASSERT
273 void verify_clear(const PSVirtualSpace* vspace);
274 void verify_clear();
275 #endif // #ifdef ASSERT
277 private:
278 bool initialize_region_data(size_t region_size);
279 PSVirtualSpace* create_vspace(size_t count, size_t element_size);
281 private:
282 HeapWord* _region_start;
283 #ifdef ASSERT
284 HeapWord* _region_end;
285 #endif // #ifdef ASSERT
287 PSVirtualSpace* _region_vspace;
288 RegionData* _region_data;
289 size_t _region_count;
290 };
292 inline uint
293 ParallelCompactData::RegionData::destination_count_raw() const
294 {
295 return _dc_and_los & dc_mask;
296 }
298 inline uint
299 ParallelCompactData::RegionData::destination_count() const
300 {
301 return destination_count_raw() >> dc_shift;
302 }
304 inline void
305 ParallelCompactData::RegionData::set_destination_count(uint count)
306 {
307 assert(count <= (dc_completed >> dc_shift), "count too large");
308 const region_sz_t live_sz = (region_sz_t) live_obj_size();
309 _dc_and_los = (count << dc_shift) | live_sz;
310 }
312 inline void ParallelCompactData::RegionData::set_live_obj_size(size_t words)
313 {
314 assert(words <= los_mask, "would overflow");
315 _dc_and_los = destination_count_raw() | (region_sz_t)words;
316 }
318 inline void ParallelCompactData::RegionData::decrement_destination_count()
319 {
320 assert(_dc_and_los < dc_claimed, "already claimed");
321 assert(_dc_and_los >= dc_one, "count would go negative");
322 Atomic::add((int)dc_mask, (volatile int*)&_dc_and_los);
323 }
325 inline HeapWord* ParallelCompactData::RegionData::data_location() const
326 {
327 DEBUG_ONLY(return _data_location;)
328 NOT_DEBUG(return NULL;)
329 }
331 inline HeapWord* ParallelCompactData::RegionData::highest_ref() const
332 {
333 DEBUG_ONLY(return _highest_ref;)
334 NOT_DEBUG(return NULL;)
335 }
337 inline void ParallelCompactData::RegionData::set_data_location(HeapWord* addr)
338 {
339 DEBUG_ONLY(_data_location = addr;)
340 }
342 inline void ParallelCompactData::RegionData::set_completed()
343 {
344 assert(claimed(), "must be claimed first");
345 _dc_and_los = dc_completed | (region_sz_t) live_obj_size();
346 }
348 // MT-unsafe claiming of a region. Should only be used during single threaded
349 // execution.
350 inline bool ParallelCompactData::RegionData::claim_unsafe()
351 {
352 if (available()) {
353 _dc_and_los |= dc_claimed;
354 return true;
355 }
356 return false;
357 }
359 inline void ParallelCompactData::RegionData::add_live_obj(size_t words)
360 {
361 assert(words <= (size_t)los_mask - live_obj_size(), "overflow");
362 Atomic::add((int) words, (volatile int*) &_dc_and_los);
363 }
365 inline void ParallelCompactData::RegionData::set_highest_ref(HeapWord* addr)
366 {
367 #ifdef ASSERT
368 HeapWord* tmp = _highest_ref;
369 while (addr > tmp) {
370 tmp = (HeapWord*)Atomic::cmpxchg_ptr(addr, &_highest_ref, tmp);
371 }
372 #endif // #ifdef ASSERT
373 }
375 inline bool ParallelCompactData::RegionData::claim()
376 {
377 const int los = (int) live_obj_size();
378 const int old = Atomic::cmpxchg(dc_claimed | los,
379 (volatile int*) &_dc_and_los, los);
380 return old == los;
381 }
383 inline ParallelCompactData::RegionData*
384 ParallelCompactData::region(size_t region_idx) const
385 {
386 assert(region_idx <= region_count(), "bad arg");
387 return _region_data + region_idx;
388 }
390 inline size_t
391 ParallelCompactData::region(const RegionData* const region_ptr) const
392 {
393 assert(region_ptr >= _region_data, "bad arg");
394 assert(region_ptr <= _region_data + region_count(), "bad arg");
395 return pointer_delta(region_ptr, _region_data, sizeof(RegionData));
396 }
398 inline size_t
399 ParallelCompactData::region_offset(const HeapWord* addr) const
400 {
401 assert(addr >= _region_start, "bad addr");
402 assert(addr <= _region_end, "bad addr");
403 return (size_t(addr) & RegionAddrOffsetMask) >> LogHeapWordSize;
404 }
406 inline size_t
407 ParallelCompactData::addr_to_region_idx(const HeapWord* addr) const
408 {
409 assert(addr >= _region_start, "bad addr");
410 assert(addr <= _region_end, "bad addr");
411 return pointer_delta(addr, _region_start) >> Log2RegionSize;
412 }
414 inline ParallelCompactData::RegionData*
415 ParallelCompactData::addr_to_region_ptr(const HeapWord* addr) const
416 {
417 return region(addr_to_region_idx(addr));
418 }
420 inline HeapWord*
421 ParallelCompactData::region_to_addr(size_t region) const
422 {
423 assert(region <= _region_count, "region out of range");
424 return _region_start + (region << Log2RegionSize);
425 }
427 inline HeapWord*
428 ParallelCompactData::region_to_addr(const RegionData* region) const
429 {
430 return region_to_addr(pointer_delta(region, _region_data,
431 sizeof(RegionData)));
432 }
434 inline HeapWord*
435 ParallelCompactData::region_to_addr(size_t region, size_t offset) const
436 {
437 assert(region <= _region_count, "region out of range");
438 assert(offset < RegionSize, "offset too big"); // This may be too strict.
439 return region_to_addr(region) + offset;
440 }
442 inline HeapWord*
443 ParallelCompactData::region_align_down(HeapWord* addr) const
444 {
445 assert(addr >= _region_start, "bad addr");
446 assert(addr < _region_end + RegionSize, "bad addr");
447 return (HeapWord*)(size_t(addr) & RegionAddrMask);
448 }
450 inline HeapWord*
451 ParallelCompactData::region_align_up(HeapWord* addr) const
452 {
453 assert(addr >= _region_start, "bad addr");
454 assert(addr <= _region_end, "bad addr");
455 return region_align_down(addr + RegionSizeOffsetMask);
456 }
458 inline bool
459 ParallelCompactData::is_region_aligned(HeapWord* addr) const
460 {
461 return region_offset(addr) == 0;
462 }
464 // Abstract closure for use with ParMarkBitMap::iterate(), which will invoke the
465 // do_addr() method.
466 //
467 // The closure is initialized with the number of heap words to process
468 // (words_remaining()), and becomes 'full' when it reaches 0. The do_addr()
469 // methods in subclasses should update the total as words are processed. Since
470 // only one subclass actually uses this mechanism to terminate iteration, the
471 // default initial value is > 0. The implementation is here and not in the
472 // single subclass that uses it to avoid making is_full() virtual, and thus
473 // adding a virtual call per live object.
475 class ParMarkBitMapClosure: public StackObj {
476 public:
477 typedef ParMarkBitMap::idx_t idx_t;
478 typedef ParMarkBitMap::IterationStatus IterationStatus;
480 public:
481 inline ParMarkBitMapClosure(ParMarkBitMap* mbm, ParCompactionManager* cm,
482 size_t words = max_uintx);
484 inline ParCompactionManager* compaction_manager() const;
485 inline ParMarkBitMap* bitmap() const;
486 inline size_t words_remaining() const;
487 inline bool is_full() const;
488 inline HeapWord* source() const;
490 inline void set_source(HeapWord* addr);
492 virtual IterationStatus do_addr(HeapWord* addr, size_t words) = 0;
494 protected:
495 inline void decrement_words_remaining(size_t words);
497 private:
498 ParMarkBitMap* const _bitmap;
499 ParCompactionManager* const _compaction_manager;
500 DEBUG_ONLY(const size_t _initial_words_remaining;) // Useful in debugger.
501 size_t _words_remaining; // Words left to copy.
503 protected:
504 HeapWord* _source; // Next addr that would be read.
505 };
507 inline
508 ParMarkBitMapClosure::ParMarkBitMapClosure(ParMarkBitMap* bitmap,
509 ParCompactionManager* cm,
510 size_t words):
511 _bitmap(bitmap), _compaction_manager(cm)
512 #ifdef ASSERT
513 , _initial_words_remaining(words)
514 #endif
515 {
516 _words_remaining = words;
517 _source = NULL;
518 }
520 inline ParCompactionManager* ParMarkBitMapClosure::compaction_manager() const {
521 return _compaction_manager;
522 }
524 inline ParMarkBitMap* ParMarkBitMapClosure::bitmap() const {
525 return _bitmap;
526 }
528 inline size_t ParMarkBitMapClosure::words_remaining() const {
529 return _words_remaining;
530 }
532 inline bool ParMarkBitMapClosure::is_full() const {
533 return words_remaining() == 0;
534 }
536 inline HeapWord* ParMarkBitMapClosure::source() const {
537 return _source;
538 }
540 inline void ParMarkBitMapClosure::set_source(HeapWord* addr) {
541 _source = addr;
542 }
544 inline void ParMarkBitMapClosure::decrement_words_remaining(size_t words) {
545 assert(_words_remaining >= words, "processed too many words");
546 _words_remaining -= words;
547 }
549 // The UseParallelOldGC collector is a stop-the-world garbage collector that
550 // does parts of the collection using parallel threads. The collection includes
551 // the tenured generation and the young generation. The permanent generation is
552 // collected at the same time as the other two generations but the permanent
553 // generation is collect by a single GC thread. The permanent generation is
554 // collected serially because of the requirement that during the processing of a
555 // klass AAA, any objects reference by AAA must already have been processed.
556 // This requirement is enforced by a left (lower address) to right (higher
557 // address) sliding compaction.
558 //
559 // There are four phases of the collection.
560 //
561 // - marking phase
562 // - summary phase
563 // - compacting phase
564 // - clean up phase
565 //
566 // Roughly speaking these phases correspond, respectively, to
567 // - mark all the live objects
568 // - calculate the destination of each object at the end of the collection
569 // - move the objects to their destination
570 // - update some references and reinitialize some variables
571 //
572 // These three phases are invoked in PSParallelCompact::invoke_no_policy(). The
573 // marking phase is implemented in PSParallelCompact::marking_phase() and does a
574 // complete marking of the heap. The summary phase is implemented in
575 // PSParallelCompact::summary_phase(). The move and update phase is implemented
576 // in PSParallelCompact::compact().
577 //
578 // A space that is being collected is divided into regions and with each region
579 // is associated an object of type ParallelCompactData. Each region is of a
580 // fixed size and typically will contain more than 1 object and may have parts
581 // of objects at the front and back of the region.
582 //
583 // region -----+---------------------+----------
584 // objects covered [ AAA )[ BBB )[ CCC )[ DDD )
585 //
586 // The marking phase does a complete marking of all live objects in the heap.
587 // The marking also compiles the size of the data for all live objects covered
588 // by the region. This size includes the part of any live object spanning onto
589 // the region (part of AAA if it is live) from the front, all live objects
590 // contained in the region (BBB and/or CCC if they are live), and the part of
591 // any live objects covered by the region that extends off the region (part of
592 // DDD if it is live). The marking phase uses multiple GC threads and marking
593 // is done in a bit array of type ParMarkBitMap. The marking of the bit map is
594 // done atomically as is the accumulation of the size of the live objects
595 // covered by a region.
596 //
597 // The summary phase calculates the total live data to the left of each region
598 // XXX. Based on that total and the bottom of the space, it can calculate the
599 // starting location of the live data in XXX. The summary phase calculates for
600 // each region XXX quantites such as
601 //
602 // - the amount of live data at the beginning of a region from an object
603 // entering the region.
604 // - the location of the first live data on the region
605 // - a count of the number of regions receiving live data from XXX.
606 //
607 // See ParallelCompactData for precise details. The summary phase also
608 // calculates the dense prefix for the compaction. The dense prefix is a
609 // portion at the beginning of the space that is not moved. The objects in the
610 // dense prefix do need to have their object references updated. See method
611 // summarize_dense_prefix().
612 //
613 // The summary phase is done using 1 GC thread.
614 //
615 // The compaction phase moves objects to their new location and updates all
616 // references in the object.
617 //
618 // A current exception is that objects that cross a region boundary are moved
619 // but do not have their references updated. References are not updated because
620 // it cannot easily be determined if the klass pointer KKK for the object AAA
621 // has been updated. KKK likely resides in a region to the left of the region
622 // containing AAA. These AAA's have there references updated at the end in a
623 // clean up phase. See the method PSParallelCompact::update_deferred_objects().
624 // An alternate strategy is being investigated for this deferral of updating.
625 //
626 // Compaction is done on a region basis. A region that is ready to be filled is
627 // put on a ready list and GC threads take region off the list and fill them. A
628 // region is ready to be filled if it empty of live objects. Such a region may
629 // have been initially empty (only contained dead objects) or may have had all
630 // its live objects copied out already. A region that compacts into itself is
631 // also ready for filling. The ready list is initially filled with empty
632 // regions and regions compacting into themselves. There is always at least 1
633 // region that can be put on the ready list. The regions are atomically added
634 // and removed from the ready list.
636 class PSParallelCompact : AllStatic {
637 public:
638 // Convenient access to type names.
639 typedef ParMarkBitMap::idx_t idx_t;
640 typedef ParallelCompactData::RegionData RegionData;
642 typedef enum {
643 perm_space_id, old_space_id, eden_space_id,
644 from_space_id, to_space_id, last_space_id
645 } SpaceId;
647 public:
648 // Inline closure decls
649 //
650 class IsAliveClosure: public BoolObjectClosure {
651 public:
652 virtual void do_object(oop p);
653 virtual bool do_object_b(oop p);
654 };
656 class KeepAliveClosure: public OopClosure {
657 private:
658 ParCompactionManager* _compaction_manager;
659 protected:
660 template <class T> inline void do_oop_work(T* p);
661 public:
662 KeepAliveClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }
663 virtual void do_oop(oop* p);
664 virtual void do_oop(narrowOop* p);
665 };
667 // Current unused
668 class FollowRootClosure: public OopsInGenClosure {
669 private:
670 ParCompactionManager* _compaction_manager;
671 public:
672 FollowRootClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }
673 virtual void do_oop(oop* p);
674 virtual void do_oop(narrowOop* p);
675 virtual const bool do_nmethods() const { return true; }
676 };
678 class FollowStackClosure: public VoidClosure {
679 private:
680 ParCompactionManager* _compaction_manager;
681 public:
682 FollowStackClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }
683 virtual void do_void();
684 };
686 class AdjustPointerClosure: public OopsInGenClosure {
687 private:
688 bool _is_root;
689 public:
690 AdjustPointerClosure(bool is_root) : _is_root(is_root) { }
691 virtual void do_oop(oop* p);
692 virtual void do_oop(narrowOop* p);
693 };
695 // Closure for verifying update of pointers. Does not
696 // have any side effects.
697 class VerifyUpdateClosure: public ParMarkBitMapClosure {
698 const MutableSpace* _space; // Is this ever used?
700 public:
701 VerifyUpdateClosure(ParCompactionManager* cm, const MutableSpace* sp) :
702 ParMarkBitMapClosure(PSParallelCompact::mark_bitmap(), cm), _space(sp)
703 { }
705 virtual IterationStatus do_addr(HeapWord* addr, size_t words);
707 const MutableSpace* space() { return _space; }
708 };
710 // Closure for updating objects altered for debug checking
711 class ResetObjectsClosure: public ParMarkBitMapClosure {
712 public:
713 ResetObjectsClosure(ParCompactionManager* cm):
714 ParMarkBitMapClosure(PSParallelCompact::mark_bitmap(), cm)
715 { }
717 virtual IterationStatus do_addr(HeapWord* addr, size_t words);
718 };
720 friend class KeepAliveClosure;
721 friend class FollowStackClosure;
722 friend class AdjustPointerClosure;
723 friend class FollowRootClosure;
724 friend class instanceKlassKlass;
725 friend class RefProcTaskProxy;
727 private:
728 static elapsedTimer _accumulated_time;
729 static unsigned int _total_invocations;
730 static unsigned int _maximum_compaction_gc_num;
731 static jlong _time_of_last_gc; // ms
732 static CollectorCounters* _counters;
733 static ParMarkBitMap _mark_bitmap;
734 static ParallelCompactData _summary_data;
735 static IsAliveClosure _is_alive_closure;
736 static SpaceInfo _space_info[last_space_id];
737 static bool _print_phases;
738 static AdjustPointerClosure _adjust_root_pointer_closure;
739 static AdjustPointerClosure _adjust_pointer_closure;
741 // Reference processing (used in ...follow_contents)
742 static ReferenceProcessor* _ref_processor;
744 // Updated location of intArrayKlassObj.
745 static klassOop _updated_int_array_klass_obj;
747 // Values computed at initialization and used by dead_wood_limiter().
748 static double _dwl_mean;
749 static double _dwl_std_dev;
750 static double _dwl_first_term;
751 static double _dwl_adjustment;
752 #ifdef ASSERT
753 static bool _dwl_initialized;
754 #endif // #ifdef ASSERT
756 private:
757 // Closure accessors
758 static OopClosure* adjust_pointer_closure() { return (OopClosure*)&_adjust_pointer_closure; }
759 static OopClosure* adjust_root_pointer_closure() { return (OopClosure*)&_adjust_root_pointer_closure; }
760 static BoolObjectClosure* is_alive_closure() { return (BoolObjectClosure*)&_is_alive_closure; }
762 static void initialize_space_info();
764 // Return true if details about individual phases should be printed.
765 static inline bool print_phases();
767 // Clear the marking bitmap and summary data that cover the specified space.
768 static void clear_data_covering_space(SpaceId id);
770 static void pre_compact(PreGCValues* pre_gc_values);
771 static void post_compact();
773 // Mark live objects
774 static void marking_phase(ParCompactionManager* cm,
775 bool maximum_heap_compaction);
776 static void follow_stack(ParCompactionManager* cm);
777 static void follow_weak_klass_links(ParCompactionManager* cm);
779 template <class T> static inline void adjust_pointer(T* p, bool is_root);
780 static void adjust_root_pointer(oop* p) { adjust_pointer(p, true); }
782 template <class T>
783 static inline void follow_root(ParCompactionManager* cm, T* p);
785 // Compute the dense prefix for the designated space. This is an experimental
786 // implementation currently not used in production.
787 static HeapWord* compute_dense_prefix_via_density(const SpaceId id,
788 bool maximum_compaction);
790 // Methods used to compute the dense prefix.
792 // Compute the value of the normal distribution at x = density. The mean and
793 // standard deviation are values saved by initialize_dead_wood_limiter().
794 static inline double normal_distribution(double density);
796 // Initialize the static vars used by dead_wood_limiter().
797 static void initialize_dead_wood_limiter();
799 // Return the percentage of space that can be treated as "dead wood" (i.e.,
800 // not reclaimed).
801 static double dead_wood_limiter(double density, size_t min_percent);
803 // Find the first (left-most) region in the range [beg, end) that has at least
804 // dead_words of dead space to the left. The argument beg must be the first
805 // region in the space that is not completely live.
806 static RegionData* dead_wood_limit_region(const RegionData* beg,
807 const RegionData* end,
808 size_t dead_words);
810 // Return a pointer to the first region in the range [beg, end) that is not
811 // completely full.
812 static RegionData* first_dead_space_region(const RegionData* beg,
813 const RegionData* end);
815 // Return a value indicating the benefit or 'yield' if the compacted region
816 // were to start (or equivalently if the dense prefix were to end) at the
817 // candidate region. Higher values are better.
818 //
819 // The value is based on the amount of space reclaimed vs. the costs of (a)
820 // updating references in the dense prefix plus (b) copying objects and
821 // updating references in the compacted region.
822 static inline double reclaimed_ratio(const RegionData* const candidate,
823 HeapWord* const bottom,
824 HeapWord* const top,
825 HeapWord* const new_top);
827 // Compute the dense prefix for the designated space.
828 static HeapWord* compute_dense_prefix(const SpaceId id,
829 bool maximum_compaction);
831 // Return true if dead space crosses onto the specified Region; bit must be
832 // the bit index corresponding to the first word of the Region.
833 static inline bool dead_space_crosses_boundary(const RegionData* region,
834 idx_t bit);
836 // Summary phase utility routine to fill dead space (if any) at the dense
837 // prefix boundary. Should only be called if the the dense prefix is
838 // non-empty.
839 static void fill_dense_prefix_end(SpaceId id);
841 static void summarize_spaces_quick();
842 static void summarize_space(SpaceId id, bool maximum_compaction);
843 static void summary_phase(ParCompactionManager* cm, bool maximum_compaction);
845 // The space that is compacted after space_id.
846 static SpaceId next_compaction_space_id(SpaceId space_id);
848 // Adjust addresses in roots. Does not adjust addresses in heap.
849 static void adjust_roots();
851 // Serial code executed in preparation for the compaction phase.
852 static void compact_prologue();
854 // Move objects to new locations.
855 static void compact_perm(ParCompactionManager* cm);
856 static void compact();
858 // Add available regions to the stack and draining tasks to the task queue.
859 static void enqueue_region_draining_tasks(GCTaskQueue* q,
860 uint parallel_gc_threads);
862 // Add dense prefix update tasks to the task queue.
863 static void enqueue_dense_prefix_tasks(GCTaskQueue* q,
864 uint parallel_gc_threads);
866 // Add region stealing tasks to the task queue.
867 static void enqueue_region_stealing_tasks(
868 GCTaskQueue* q,
869 ParallelTaskTerminator* terminator_ptr,
870 uint parallel_gc_threads);
872 // For debugging only - compacts the old gen serially
873 static void compact_serial(ParCompactionManager* cm);
875 // If objects are left in eden after a collection, try to move the boundary
876 // and absorb them into the old gen. Returns true if eden was emptied.
877 static bool absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
878 PSYoungGen* young_gen,
879 PSOldGen* old_gen);
881 // Reset time since last full gc
882 static void reset_millis_since_last_gc();
884 protected:
885 #ifdef VALIDATE_MARK_SWEEP
886 static GrowableArray<void*>* _root_refs_stack;
887 static GrowableArray<oop> * _live_oops;
888 static GrowableArray<oop> * _live_oops_moved_to;
889 static GrowableArray<size_t>* _live_oops_size;
890 static size_t _live_oops_index;
891 static size_t _live_oops_index_at_perm;
892 static GrowableArray<void*>* _other_refs_stack;
893 static GrowableArray<void*>* _adjusted_pointers;
894 static bool _pointer_tracking;
895 static bool _root_tracking;
897 // The following arrays are saved since the time of the last GC and
898 // assist in tracking down problems where someone has done an errant
899 // store into the heap, usually to an oop that wasn't properly
900 // handleized across a GC. If we crash or otherwise fail before the
901 // next GC, we can query these arrays to find out the object we had
902 // intended to do the store to (assuming it is still alive) and the
903 // offset within that object. Covered under RecordMarkSweepCompaction.
904 static GrowableArray<HeapWord*> * _cur_gc_live_oops;
905 static GrowableArray<HeapWord*> * _cur_gc_live_oops_moved_to;
906 static GrowableArray<size_t>* _cur_gc_live_oops_size;
907 static GrowableArray<HeapWord*> * _last_gc_live_oops;
908 static GrowableArray<HeapWord*> * _last_gc_live_oops_moved_to;
909 static GrowableArray<size_t>* _last_gc_live_oops_size;
910 #endif
912 public:
913 class MarkAndPushClosure: public OopClosure {
914 private:
915 ParCompactionManager* _compaction_manager;
916 public:
917 MarkAndPushClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }
918 virtual void do_oop(oop* p);
919 virtual void do_oop(narrowOop* p);
920 virtual const bool do_nmethods() const { return true; }
921 };
923 PSParallelCompact();
925 // Convenient accessor for Universe::heap().
926 static ParallelScavengeHeap* gc_heap() {
927 return (ParallelScavengeHeap*)Universe::heap();
928 }
930 static void invoke(bool maximum_heap_compaction);
931 static void invoke_no_policy(bool maximum_heap_compaction);
933 static void post_initialize();
934 // Perform initialization for PSParallelCompact that requires
935 // allocations. This should be called during the VM initialization
936 // at a pointer where it would be appropriate to return a JNI_ENOMEM
937 // in the event of a failure.
938 static bool initialize();
940 // Public accessors
941 static elapsedTimer* accumulated_time() { return &_accumulated_time; }
942 static unsigned int total_invocations() { return _total_invocations; }
943 static CollectorCounters* counters() { return _counters; }
945 // Used to add tasks
946 static GCTaskManager* const gc_task_manager();
947 static klassOop updated_int_array_klass_obj() {
948 return _updated_int_array_klass_obj;
949 }
951 // Marking support
952 static inline bool mark_obj(oop obj);
953 // Check mark and maybe push on marking stack
954 template <class T> static inline void mark_and_push(ParCompactionManager* cm,
955 T* p);
957 // Compaction support.
958 // Return true if p is in the range [beg_addr, end_addr).
959 static inline bool is_in(HeapWord* p, HeapWord* beg_addr, HeapWord* end_addr);
960 static inline bool is_in(oop* p, HeapWord* beg_addr, HeapWord* end_addr);
962 // Convenience wrappers for per-space data kept in _space_info.
963 static inline MutableSpace* space(SpaceId space_id);
964 static inline HeapWord* new_top(SpaceId space_id);
965 static inline HeapWord* dense_prefix(SpaceId space_id);
966 static inline ObjectStartArray* start_array(SpaceId space_id);
968 // Return true if the klass should be updated.
969 static inline bool should_update_klass(klassOop k);
971 // Move and update the live objects in the specified space.
972 static void move_and_update(ParCompactionManager* cm, SpaceId space_id);
974 // Process the end of the given region range in the dense prefix.
975 // This includes saving any object not updated.
976 static void dense_prefix_regions_epilogue(ParCompactionManager* cm,
977 size_t region_start_index,
978 size_t region_end_index,
979 idx_t exiting_object_offset,
980 idx_t region_offset_start,
981 idx_t region_offset_end);
983 // Update a region in the dense prefix. For each live object
984 // in the region, update it's interior references. For each
985 // dead object, fill it with deadwood. Dead space at the end
986 // of a region range will be filled to the start of the next
987 // live object regardless of the region_index_end. None of the
988 // objects in the dense prefix move and dead space is dead
989 // (holds only dead objects that don't need any processing), so
990 // dead space can be filled in any order.
991 static void update_and_deadwood_in_dense_prefix(ParCompactionManager* cm,
992 SpaceId space_id,
993 size_t region_index_start,
994 size_t region_index_end);
996 // Return the address of the count + 1st live word in the range [beg, end).
997 static HeapWord* skip_live_words(HeapWord* beg, HeapWord* end, size_t count);
999 // Return the address of the word to be copied to dest_addr, which must be
1000 // aligned to a region boundary.
1001 static HeapWord* first_src_addr(HeapWord* const dest_addr,
1002 size_t src_region_idx);
1004 // Determine the next source region, set closure.source() to the start of the
1005 // new region return the region index. Parameter end_addr is the address one
1006 // beyond the end of source range just processed. If necessary, switch to a
1007 // new source space and set src_space_id (in-out parameter) and src_space_top
1008 // (out parameter) accordingly.
1009 static size_t next_src_region(MoveAndUpdateClosure& closure,
1010 SpaceId& src_space_id,
1011 HeapWord*& src_space_top,
1012 HeapWord* end_addr);
1014 // Decrement the destination count for each non-empty source region in the
1015 // range [beg_region, region(region_align_up(end_addr))).
1016 static void decrement_destination_counts(ParCompactionManager* cm,
1017 size_t beg_region,
1018 HeapWord* end_addr);
1020 // Fill a region, copying objects from one or more source regions.
1021 static void fill_region(ParCompactionManager* cm, size_t region_idx);
1022 static void fill_and_update_region(ParCompactionManager* cm, size_t region) {
1023 fill_region(cm, region);
1024 }
1026 // Update the deferred objects in the space.
1027 static void update_deferred_objects(ParCompactionManager* cm, SpaceId id);
1029 // Mark pointer and follow contents.
1030 template <class T>
1031 static inline void mark_and_follow(ParCompactionManager* cm, T* p);
1033 static ParMarkBitMap* mark_bitmap() { return &_mark_bitmap; }
1034 static ParallelCompactData& summary_data() { return _summary_data; }
1036 static inline void adjust_pointer(oop* p) { adjust_pointer(p, false); }
1037 static inline void adjust_pointer(narrowOop* p) { adjust_pointer(p, false); }
1039 template <class T>
1040 static inline void adjust_pointer(T* p,
1041 HeapWord* beg_addr,
1042 HeapWord* end_addr);
1044 // Reference Processing
1045 static ReferenceProcessor* const ref_processor() { return _ref_processor; }
1047 // Return the SpaceId for the given address.
1048 static SpaceId space_id(HeapWord* addr);
1050 // Time since last full gc (in milliseconds).
1051 static jlong millis_since_last_gc();
1053 #ifdef VALIDATE_MARK_SWEEP
1054 static void track_adjusted_pointer(void* p, bool isroot);
1055 static void check_adjust_pointer(void* p);
1056 static void track_interior_pointers(oop obj);
1057 static void check_interior_pointers();
1059 static void reset_live_oop_tracking(bool at_perm);
1060 static void register_live_oop(oop p, size_t size);
1061 static void validate_live_oop(oop p, size_t size);
1062 static void live_oop_moved_to(HeapWord* q, size_t size, HeapWord* compaction_top);
1063 static void compaction_complete();
1065 // Querying operation of RecordMarkSweepCompaction results.
1066 // Finds and prints the current base oop and offset for a word
1067 // within an oop that was live during the last GC. Helpful for
1068 // tracking down heap stomps.
1069 static void print_new_location_of_heap_address(HeapWord* q);
1070 #endif // #ifdef VALIDATE_MARK_SWEEP
1072 // Call backs for class unloading
1073 // Update subklass/sibling/implementor links at end of marking.
1074 static void revisit_weak_klass_link(ParCompactionManager* cm, Klass* k);
1076 #ifndef PRODUCT
1077 // Debugging support.
1078 static const char* space_names[last_space_id];
1079 static void print_region_ranges();
1080 static void print_dense_prefix_stats(const char* const algorithm,
1081 const SpaceId id,
1082 const bool maximum_compaction,
1083 HeapWord* const addr);
1084 #endif // #ifndef PRODUCT
1086 #ifdef ASSERT
1087 // Verify that all the regions have been emptied.
1088 static void verify_complete(SpaceId space_id);
1089 #endif // #ifdef ASSERT
1090 };
1092 inline bool PSParallelCompact::mark_obj(oop obj) {
1093 const int obj_size = obj->size();
1094 if (mark_bitmap()->mark_obj(obj, obj_size)) {
1095 _summary_data.add_obj(obj, obj_size);
1096 return true;
1097 } else {
1098 return false;
1099 }
1100 }
1102 template <class T>
1103 inline void PSParallelCompact::follow_root(ParCompactionManager* cm, T* p) {
1104 assert(!Universe::heap()->is_in_reserved(p),
1105 "roots shouldn't be things within the heap");
1106 #ifdef VALIDATE_MARK_SWEEP
1107 if (ValidateMarkSweep) {
1108 guarantee(!_root_refs_stack->contains(p), "should only be in here once");
1109 _root_refs_stack->push(p);
1110 }
1111 #endif
1112 T heap_oop = oopDesc::load_heap_oop(p);
1113 if (!oopDesc::is_null(heap_oop)) {
1114 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
1115 if (mark_bitmap()->is_unmarked(obj)) {
1116 if (mark_obj(obj)) {
1117 obj->follow_contents(cm);
1118 }
1119 }
1120 }
1121 follow_stack(cm);
1122 }
1124 template <class T>
1125 inline void PSParallelCompact::mark_and_follow(ParCompactionManager* cm,
1126 T* p) {
1127 T heap_oop = oopDesc::load_heap_oop(p);
1128 if (!oopDesc::is_null(heap_oop)) {
1129 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
1130 if (mark_bitmap()->is_unmarked(obj)) {
1131 if (mark_obj(obj)) {
1132 obj->follow_contents(cm);
1133 }
1134 }
1135 }
1136 }
1138 template <class T>
1139 inline void PSParallelCompact::mark_and_push(ParCompactionManager* cm, T* p) {
1140 T heap_oop = oopDesc::load_heap_oop(p);
1141 if (!oopDesc::is_null(heap_oop)) {
1142 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
1143 if (mark_bitmap()->is_unmarked(obj)) {
1144 if (mark_obj(obj)) {
1145 // This thread marked the object and owns the subsequent processing of it.
1146 cm->save_for_scanning(obj);
1147 }
1148 }
1149 }
1150 }
1152 template <class T>
1153 inline void PSParallelCompact::adjust_pointer(T* p, bool isroot) {
1154 T heap_oop = oopDesc::load_heap_oop(p);
1155 if (!oopDesc::is_null(heap_oop)) {
1156 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
1157 oop new_obj = (oop)summary_data().calc_new_pointer(obj);
1158 assert(new_obj != NULL || // is forwarding ptr?
1159 obj->is_shared(), // never forwarded?
1160 "should be forwarded");
1161 // Just always do the update unconditionally?
1162 if (new_obj != NULL) {
1163 assert(Universe::heap()->is_in_reserved(new_obj),
1164 "should be in object space");
1165 oopDesc::encode_store_heap_oop_not_null(p, new_obj);
1166 }
1167 }
1168 VALIDATE_MARK_SWEEP_ONLY(track_adjusted_pointer(p, isroot));
1169 }
1171 template <class T>
1172 inline void PSParallelCompact::KeepAliveClosure::do_oop_work(T* p) {
1173 #ifdef VALIDATE_MARK_SWEEP
1174 if (ValidateMarkSweep) {
1175 if (!Universe::heap()->is_in_reserved(p)) {
1176 _root_refs_stack->push(p);
1177 } else {
1178 _other_refs_stack->push(p);
1179 }
1180 }
1181 #endif
1182 mark_and_push(_compaction_manager, p);
1183 }
1185 inline bool PSParallelCompact::print_phases() {
1186 return _print_phases;
1187 }
1189 inline double PSParallelCompact::normal_distribution(double density) {
1190 assert(_dwl_initialized, "uninitialized");
1191 const double squared_term = (density - _dwl_mean) / _dwl_std_dev;
1192 return _dwl_first_term * exp(-0.5 * squared_term * squared_term);
1193 }
1195 inline bool
1196 PSParallelCompact::dead_space_crosses_boundary(const RegionData* region,
1197 idx_t bit)
1198 {
1199 assert(bit > 0, "cannot call this for the first bit/region");
1200 assert(_summary_data.region_to_addr(region) == _mark_bitmap.bit_to_addr(bit),
1201 "sanity check");
1203 // Dead space crosses the boundary if (1) a partial object does not extend
1204 // onto the region, (2) an object does not start at the beginning of the
1205 // region, and (3) an object does not end at the end of the prior region.
1206 return region->partial_obj_size() == 0 &&
1207 !_mark_bitmap.is_obj_beg(bit) &&
1208 !_mark_bitmap.is_obj_end(bit - 1);
1209 }
1211 inline bool
1212 PSParallelCompact::is_in(HeapWord* p, HeapWord* beg_addr, HeapWord* end_addr) {
1213 return p >= beg_addr && p < end_addr;
1214 }
1216 inline bool
1217 PSParallelCompact::is_in(oop* p, HeapWord* beg_addr, HeapWord* end_addr) {
1218 return is_in((HeapWord*)p, beg_addr, end_addr);
1219 }
1221 inline MutableSpace* PSParallelCompact::space(SpaceId id) {
1222 assert(id < last_space_id, "id out of range");
1223 return _space_info[id].space();
1224 }
1226 inline HeapWord* PSParallelCompact::new_top(SpaceId id) {
1227 assert(id < last_space_id, "id out of range");
1228 return _space_info[id].new_top();
1229 }
1231 inline HeapWord* PSParallelCompact::dense_prefix(SpaceId id) {
1232 assert(id < last_space_id, "id out of range");
1233 return _space_info[id].dense_prefix();
1234 }
1236 inline ObjectStartArray* PSParallelCompact::start_array(SpaceId id) {
1237 assert(id < last_space_id, "id out of range");
1238 return _space_info[id].start_array();
1239 }
1241 inline bool PSParallelCompact::should_update_klass(klassOop k) {
1242 return ((HeapWord*) k) >= dense_prefix(perm_space_id);
1243 }
1245 template <class T>
1246 inline void PSParallelCompact::adjust_pointer(T* p,
1247 HeapWord* beg_addr,
1248 HeapWord* end_addr) {
1249 if (is_in((HeapWord*)p, beg_addr, end_addr)) {
1250 adjust_pointer(p);
1251 }
1252 }
1254 class MoveAndUpdateClosure: public ParMarkBitMapClosure {
1255 public:
1256 inline MoveAndUpdateClosure(ParMarkBitMap* bitmap, ParCompactionManager* cm,
1257 ObjectStartArray* start_array,
1258 HeapWord* destination, size_t words);
1260 // Accessors.
1261 HeapWord* destination() const { return _destination; }
1263 // If the object will fit (size <= words_remaining()), copy it to the current
1264 // destination, update the interior oops and the start array and return either
1265 // full (if the closure is full) or incomplete. If the object will not fit,
1266 // return would_overflow.
1267 virtual IterationStatus do_addr(HeapWord* addr, size_t size);
1269 // Copy enough words to fill this closure, starting at source(). Interior
1270 // oops and the start array are not updated. Return full.
1271 IterationStatus copy_until_full();
1273 // Copy enough words to fill this closure or to the end of an object,
1274 // whichever is smaller, starting at source(). Interior oops and the start
1275 // array are not updated.
1276 void copy_partial_obj();
1278 protected:
1279 // Update variables to indicate that word_count words were processed.
1280 inline void update_state(size_t word_count);
1282 protected:
1283 ObjectStartArray* const _start_array;
1284 HeapWord* _destination; // Next addr to be written.
1285 };
1287 inline
1288 MoveAndUpdateClosure::MoveAndUpdateClosure(ParMarkBitMap* bitmap,
1289 ParCompactionManager* cm,
1290 ObjectStartArray* start_array,
1291 HeapWord* destination,
1292 size_t words) :
1293 ParMarkBitMapClosure(bitmap, cm, words), _start_array(start_array)
1294 {
1295 _destination = destination;
1296 }
1298 inline void MoveAndUpdateClosure::update_state(size_t words)
1299 {
1300 decrement_words_remaining(words);
1301 _source += words;
1302 _destination += words;
1303 }
1305 class UpdateOnlyClosure: public ParMarkBitMapClosure {
1306 private:
1307 const PSParallelCompact::SpaceId _space_id;
1308 ObjectStartArray* const _start_array;
1310 public:
1311 UpdateOnlyClosure(ParMarkBitMap* mbm,
1312 ParCompactionManager* cm,
1313 PSParallelCompact::SpaceId space_id);
1315 // Update the object.
1316 virtual IterationStatus do_addr(HeapWord* addr, size_t words);
1318 inline void do_addr(HeapWord* addr);
1319 };
1321 inline void UpdateOnlyClosure::do_addr(HeapWord* addr)
1322 {
1323 _start_array->allocate_block(addr);
1324 oop(addr)->update_contents(compaction_manager());
1325 }
1327 class FillClosure: public ParMarkBitMapClosure {
1328 public:
1329 FillClosure(ParCompactionManager* cm, PSParallelCompact::SpaceId space_id) :
1330 ParMarkBitMapClosure(PSParallelCompact::mark_bitmap(), cm),
1331 _space_id(space_id),
1332 _start_array(PSParallelCompact::start_array(space_id)) {
1333 assert(_space_id == PSParallelCompact::perm_space_id ||
1334 _space_id == PSParallelCompact::old_space_id,
1335 "cannot use FillClosure in the young gen");
1336 assert(bitmap() != NULL, "need a bitmap");
1337 assert(_start_array != NULL, "need a start array");
1338 }
1340 void fill_region(HeapWord* addr, size_t size) {
1341 MemRegion region(addr, size);
1342 SharedHeap::fill_region_with_object(region);
1343 _start_array->allocate_block(addr);
1344 }
1346 virtual IterationStatus do_addr(HeapWord* addr, size_t size) {
1347 fill_region(addr, size);
1348 return ParMarkBitMap::incomplete;
1349 }
1351 private:
1352 const PSParallelCompact::SpaceId _space_id;
1353 ObjectStartArray* const _start_array;
1354 };