1 #ifdef USE_PRAGMA_IDENT_HDR
2 #pragma ident "@(#)psParallelCompact.hpp 1.48 07/10/04 10:49:38 JVM"
3 #endif
4 /*
5 * Copyright 2005-2008 Sun Microsystems, Inc. All Rights Reserved.
6 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
7 *
8 * This code is free software; you can redistribute it and/or modify it
9 * under the terms of the GNU General Public License version 2 only, as
10 * published by the Free Software Foundation.
11 *
12 * This code is distributed in the hope that it will be useful, but WITHOUT
13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 * version 2 for more details (a copy is included in the LICENSE file that
16 * accompanied this code).
17 *
18 * You should have received a copy of the GNU General Public License version
19 * 2 along with this work; if not, write to the Free Software Foundation,
20 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
21 *
22 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
23 * CA 95054 USA or visit www.sun.com if you need additional information or
24 * have any questions.
25 *
26 */
27
28 class ParallelScavengeHeap;
29 class PSAdaptiveSizePolicy;
30 class PSYoungGen;
31 class PSOldGen;
32 class PSPermGen;
33 class ParCompactionManager;
34 class ParallelTaskTerminator;
35 class PSParallelCompact;
36 class GCTaskManager;
37 class GCTaskQueue;
38 class PreGCValues;
39 class MoveAndUpdateClosure;
40 class RefProcTaskExecutor;
41
42 // The SplitInfo class holds the information needed to 'split' a source region
43 // so that the live data can be copied to two destination *spaces*. Normally,
44 // all the live data in a region is copied to a single destination space (e.g.,
45 // everything live in a region in eden is copied entirely into the old gen).
46 // However, when the heap is nearly full, all the live data in eden may not fit
47 // into the old gen. Copying only some of the regions from eden to old gen
48 // requires finding a region that does not contain a partial object (i.e., no
49 // live object crosses the region boundary) somewhere near the last object that
50 // does fit into the old gen. Since it's not always possible to find such a
51 // region, splitting is necessary for predictable behavior.
52 //
53 // A region is always split at the end of the partial object. This avoids
54 // additional tests when calculating the new location of a pointer, which is a
55 // very hot code path. The partial object and everything to its left will be
56 // copied to another space (call it dest_space_1). The live data to the right
57 // of the partial object will be copied either within the space itself, or to a
58 // different destination space (distinct from dest_space_1).
59 //
60 // Split points are identified during the summary phase, when region
61 // destinations are computed: data about the split, including the
62 // partial_object_size, is recorded in a SplitInfo record and the
63 // partial_object_size field in the summary data is set to zero. The zeroing is
64 // possible (and necessary) since the partial object will move to a different
65 // destination space than anything to its right, thus the partial object should
66 // not affect the locations of any objects to its right.
67 //
68 // The recorded data is used during the compaction phase, but only rarely: when
69 // the partial object on the split region will be copied across a destination
70 // region boundary. This test is made once each time a region is filled, and is
71 // a simple address comparison, so the overhead is negligible (see
72 // PSParallelCompact::first_src_addr()).
73 //
74 // Notes:
75 //
76 // Only regions with partial objects are split; a region without a partial
77 // object does not need any extra bookkeeping.
78 //
79 // At most one region is split per space, so the amount of data required is
80 // constant.
81 //
82 // A region is split only when the destination space would overflow. Once that
83 // happens, the destination space is abandoned and no other data (even from
84 // other source spaces) is targeted to that destination space. Abandoning the
85 // destination space may leave a somewhat large unused area at the end, if a
86 // large object caused the overflow.
87 //
88 // Future work:
89 //
90 // More bookkeeping would be required to continue to use the destination space.
91 // The most general solution would allow data from regions in two different
92 // source spaces to be "joined" in a single destination region. At the very
93 // least, additional code would be required in next_src_region() to detect the
94 // join and skip to an out-of-order source region. If the join region was also
95 // the last destination region to which a split region was copied (the most
96 // likely case), then additional work would be needed to get fill_region() to
97 // stop iteration and switch to a new source region at the right point. Basic
98 // idea would be to use a fake value for the top of the source space. It is
99 // doable, if a bit tricky.
100 //
101 // A simpler (but less general) solution would fill the remainder of the
102 // destination region with a dummy object and continue filling the next
103 // destination region.
104
105 class SplitInfo
106 {
107 public:
108 // Return true if this split info is valid (i.e., if a split has been
109 // recorded). The very first region cannot have a partial object and thus is
110 // never split, so 0 is the 'invalid' value.
111 bool is_valid() const { return _src_region_idx > 0; }
112
113 // Return true if this split holds data for the specified source region.
114 inline bool is_split(size_t source_region) const;
115
116 // The index of the split region, the size of the partial object on that
117 // region and the destination of the partial object.
118 size_t src_region_idx() const { return _src_region_idx; }
119 size_t partial_obj_size() const { return _partial_obj_size; }
120 HeapWord* destination() const { return _destination; }
121
122 // The destination count of the partial object referenced by this split
123 // (either 1 or 2). This must be added to the destination count of the
124 // remainder of the source region.
125 unsigned int destination_count() const { return _destination_count; }
126
127 // If a word within the partial object will be written to the first word of a
128 // destination region, this is the address of the destination region;
129 // otherwise this is NULL.
130 HeapWord* dest_region_addr() const { return _dest_region_addr; }
131
132 // If a word within the partial object will be written to the first word of a
133 // destination region, this is the address of that word within the partial
134 // object; otherwise this is NULL.
135 HeapWord* first_src_addr() const { return _first_src_addr; }
136
137 // Record the data necessary to split the region src_region_idx.
138 void record(size_t src_region_idx, size_t partial_obj_size,
139 HeapWord* destination);
140
141 void clear();
142
143 DEBUG_ONLY(void verify_clear();)
144
145 private:
146 size_t _src_region_idx;
147 size_t _partial_obj_size;
148 HeapWord* _destination;
149 unsigned int _destination_count;
150 HeapWord* _dest_region_addr;
151 HeapWord* _first_src_addr;
152 };
153
154 inline bool SplitInfo::is_split(size_t region_idx) const
155 {
156 return _src_region_idx == region_idx && is_valid();
157 }
158
159 class SpaceInfo
160 {
161 public:
162 MutableSpace* space() const { return _space; }
163
164 // Where the free space will start after the collection. Valid only after the
165 // summary phase completes.
166 HeapWord* new_top() const { return _new_top; }
167
168 // Allows new_top to be set.
169 HeapWord** new_top_addr() { return &_new_top; }
170
171 // Where the smallest allowable dense prefix ends (used only for perm gen).
172 HeapWord* min_dense_prefix() const { return _min_dense_prefix; }
173
174 // Where the dense prefix ends, or the compacted region begins.
175 HeapWord* dense_prefix() const { return _dense_prefix; }
176
177 // The start array for the (generation containing the) space, or NULL if there
178 // is no start array.
179 ObjectStartArray* start_array() const { return _start_array; }
180
181 SplitInfo& split_info() { return _split_info; }
182
183 void set_space(MutableSpace* s) { _space = s; }
184 void set_new_top(HeapWord* addr) { _new_top = addr; }
185 void set_min_dense_prefix(HeapWord* addr) { _min_dense_prefix = addr; }
186 void set_dense_prefix(HeapWord* addr) { _dense_prefix = addr; }
187 void set_start_array(ObjectStartArray* s) { _start_array = s; }
188
189 void publish_new_top() const { _space->set_top(_new_top); }
190
191 private:
192 MutableSpace* _space;
193 HeapWord* _new_top;
194 HeapWord* _min_dense_prefix;
195 HeapWord* _dense_prefix;
196 ObjectStartArray* _start_array;
197 SplitInfo _split_info;
198 };
199
200 class ParallelCompactData
201 {
202 public:
203 // Sizes are in HeapWords, unless indicated otherwise.
204 static const size_t Log2RegionSize;
205 static const size_t RegionSize;
206 static const size_t RegionSizeBytes;
207
208 // Mask for the bits in a size_t to get an offset within a region.
209 static const size_t RegionSizeOffsetMask;
210 // Mask for the bits in a pointer to get an offset within a region.
211 static const size_t RegionAddrOffsetMask;
212 // Mask for the bits in a pointer to get the address of the start of a region.
213 static const size_t RegionAddrMask;
214
215 class RegionData
216 {
217 public:
218 // Destination address of the region.
219 HeapWord* destination() const { return _destination; }
220
221 // The first region containing data destined for this region.
222 size_t source_region() const { return _source_region; }
223
224 // The object (if any) starting in this region and ending in a different
225 // region that could not be updated during the main (parallel) compaction
226 // phase. This is different from _partial_obj_addr, which is an object that
227 // extends onto a source region. However, the two uses do not overlap in
228 // time, so the same field is used to save space.
229 HeapWord* deferred_obj_addr() const { return _partial_obj_addr; }
230
231 // The starting address of the partial object extending onto the region.
232 HeapWord* partial_obj_addr() const { return _partial_obj_addr; }
233
234 // Size of the partial object extending onto the region (words).
235 size_t partial_obj_size() const { return _partial_obj_size; }
236
237 // Size of live data that lies within this region due to objects that start
238 // in this region (words). This does not include the partial object
239 // extending onto the region (if any), or the part of an object that extends
240 // onto the next region (if any).
241 size_t live_obj_size() const { return _dc_and_los & los_mask; }
242
243 // Total live data that lies within the region (words).
244 size_t data_size() const { return partial_obj_size() + live_obj_size(); }
245
246 // The destination_count is the number of other regions to which data from
247 // this region will be copied. At the end of the summary phase, the valid
248 // values of destination_count are
249 //
250 // 0 - data from the region will be compacted completely into itself, or the
251 // region is empty. The region can be claimed and then filled.
252 // 1 - data from the region will be compacted into 1 other region; some
253 // data from the region may also be compacted into the region itself.
254 // 2 - data from the region will be copied to 2 other regions.
255 //
256 // During compaction as regions are emptied, the destination_count is
257 // decremented (atomically) and when it reaches 0, it can be claimed and
258 // then filled.
259 //
260 // A region is claimed for processing by atomically changing the
261 // destination_count to the claimed value (dc_claimed). After a region has
262 // been filled, the destination_count should be set to the completed value
263 // (dc_completed).
264 inline uint destination_count() const;
265 inline uint destination_count_raw() const;
266
267 // The location of the java heap data that corresponds to this region.
268 inline HeapWord* data_location() const;
269
270 // The highest address referenced by objects in this region.
271 inline HeapWord* highest_ref() const;
272
273 // Whether this region is available to be claimed, has been claimed, or has
274 // been completed.
275 //
276 // Minor subtlety: claimed() returns true if the region is marked
277 // completed(), which is desirable since a region must be claimed before it
278 // can be completed.
279 bool available() const { return _dc_and_los < dc_one; }
280 bool claimed() const { return _dc_and_los >= dc_claimed; }
281 bool completed() const { return _dc_and_los >= dc_completed; }
282
283 // These are not atomic.
284 void set_destination(HeapWord* addr) { _destination = addr; }
285 void set_source_region(size_t region) { _source_region = region; }
286 void set_deferred_obj_addr(HeapWord* addr) { _partial_obj_addr = addr; }
287 void set_partial_obj_addr(HeapWord* addr) { _partial_obj_addr = addr; }
288 void set_partial_obj_size(size_t words) {
289 _partial_obj_size = (region_sz_t) words;
290 }
291
292 inline void set_destination_count(uint count);
293 inline void set_live_obj_size(size_t words);
294 inline void set_data_location(HeapWord* addr);
295 inline void set_completed();
296 inline bool claim_unsafe();
297
298 // These are atomic.
299 inline void add_live_obj(size_t words);
300 inline void set_highest_ref(HeapWord* addr);
301 inline void decrement_destination_count();
302 inline bool claim();
303
304 private:
305 // The type used to represent object sizes within a region.
306 typedef uint region_sz_t;
307
308 // Constants for manipulating the _dc_and_los field, which holds both the
309 // destination count and live obj size. The live obj size lives at the
310 // least significant end so no masking is necessary when adding.
311 static const region_sz_t dc_shift; // Shift amount.
312 static const region_sz_t dc_mask; // Mask for destination count.
313 static const region_sz_t dc_one; // 1, shifted appropriately.
314 static const region_sz_t dc_claimed; // Region has been claimed.
315 static const region_sz_t dc_completed; // Region has been completed.
316 static const region_sz_t los_mask; // Mask for live obj size.
317
318 HeapWord* _destination;
319 size_t _source_region;
320 HeapWord* _partial_obj_addr;
321 region_sz_t _partial_obj_size;
322 region_sz_t volatile _dc_and_los;
323 #ifdef ASSERT
324 // These enable optimizations that are only partially implemented. Use
325 // debug builds to prevent the code fragments from breaking.
326 HeapWord* _data_location;
327 HeapWord* _highest_ref;
328 #endif // #ifdef ASSERT
329
330 #ifdef ASSERT
331 public:
332 uint _pushed; // 0 until region is pushed onto a worker's stack
333 private:
334 #endif
335 };
336
337 public:
338 ParallelCompactData();
339 bool initialize(MemRegion covered_region);
340
341 size_t region_count() const { return _region_count; }
342
343 // Convert region indices to/from RegionData pointers.
344 inline RegionData* region(size_t region_idx) const;
345 inline size_t region(const RegionData* const region_ptr) const;
346
347 // Returns true if the given address is contained within the region
348 bool region_contains(size_t region_index, HeapWord* addr);
349
350 void add_obj(HeapWord* addr, size_t len);
351 void add_obj(oop p, size_t len) { add_obj((HeapWord*)p, len); }
352
353 // Fill in the regions covering [beg, end) so that no data moves; i.e., the
354 // destination of region n is simply the start of region n. The argument beg
355 // must be region-aligned; end need not be.
356 void summarize_dense_prefix(HeapWord* beg, HeapWord* end);
357
358 HeapWord* summarize_split_space(size_t src_region, SplitInfo& split_info,
359 HeapWord* destination, HeapWord* target_end,
360 HeapWord** target_next);
361 bool summarize(SplitInfo& split_info,
362 HeapWord* source_beg, HeapWord* source_end,
363 HeapWord** source_next,
364 HeapWord* target_beg, HeapWord* target_end,
365 HeapWord** target_next);
366
367 void clear();
368 void clear_range(size_t beg_region, size_t end_region);
369 void clear_range(HeapWord* beg, HeapWord* end) {
370 clear_range(addr_to_region_idx(beg), addr_to_region_idx(end));
371 }
372
373 // Return the number of words between addr and the start of the region
374 // containing addr.
375 inline size_t region_offset(const HeapWord* addr) const;
376
377 // Convert addresses to/from a region index or region pointer.
378 inline size_t addr_to_region_idx(const HeapWord* addr) const;
379 inline RegionData* addr_to_region_ptr(const HeapWord* addr) const;
380 inline HeapWord* region_to_addr(size_t region) const;
381 inline HeapWord* region_to_addr(size_t region, size_t offset) const;
382 inline HeapWord* region_to_addr(const RegionData* region) const;
383
384 inline HeapWord* region_align_down(HeapWord* addr) const;
385 inline HeapWord* region_align_up(HeapWord* addr) const;
386 inline bool is_region_aligned(HeapWord* addr) const;
387
388 // Return the address one past the end of the partial object.
389 HeapWord* partial_obj_end(size_t region_idx) const;
390
391 // Return the new location of the object p after the
392 // the compaction.
393 HeapWord* calc_new_pointer(HeapWord* addr);
394
395 HeapWord* calc_new_pointer(oop p) {
396 return calc_new_pointer((HeapWord*) p);
397 }
398
399 // Return the updated address for the given klass
400 klassOop calc_new_klass(klassOop);
401
402 #ifdef ASSERT
403 void verify_clear(const PSVirtualSpace* vspace);
404 void verify_clear();
405 #endif // #ifdef ASSERT
406
407 private:
408 bool initialize_region_data(size_t region_size);
409 PSVirtualSpace* create_vspace(size_t count, size_t element_size);
410
411 private:
412 HeapWord* _region_start;
413 #ifdef ASSERT
414 HeapWord* _region_end;
415 #endif // #ifdef ASSERT
416
417 PSVirtualSpace* _region_vspace;
418 RegionData* _region_data;
419 size_t _region_count;
420 };
421
422 inline uint
423 ParallelCompactData::RegionData::destination_count_raw() const
424 {
425 return _dc_and_los & dc_mask;
426 }
427
428 inline uint
429 ParallelCompactData::RegionData::destination_count() const
430 {
431 return destination_count_raw() >> dc_shift;
432 }
433
434 inline void
435 ParallelCompactData::RegionData::set_destination_count(uint count)
436 {
437 assert(count <= (dc_completed >> dc_shift), "count too large");
438 const region_sz_t live_sz = (region_sz_t) live_obj_size();
439 _dc_and_los = (count << dc_shift) | live_sz;
440 }
441
442 inline void ParallelCompactData::RegionData::set_live_obj_size(size_t words)
443 {
444 assert(words <= los_mask, "would overflow");
445 _dc_and_los = destination_count_raw() | (region_sz_t)words;
446 }
447
448 inline void ParallelCompactData::RegionData::decrement_destination_count()
449 {
450 assert(_dc_and_los < dc_claimed, "already claimed");
451 assert(_dc_and_los >= dc_one, "count would go negative");
452 Atomic::add((int)dc_mask, (volatile int*)&_dc_and_los);
453 }
454
455 inline HeapWord* ParallelCompactData::RegionData::data_location() const
456 {
457 DEBUG_ONLY(return _data_location;)
458 NOT_DEBUG(return NULL;)
459 }
460
461 inline HeapWord* ParallelCompactData::RegionData::highest_ref() const
462 {
463 DEBUG_ONLY(return _highest_ref;)
464 NOT_DEBUG(return NULL;)
465 }
466
467 inline void ParallelCompactData::RegionData::set_data_location(HeapWord* addr)
468 {
469 DEBUG_ONLY(_data_location = addr;)
470 }
471
472 inline void ParallelCompactData::RegionData::set_completed()
473 {
474 assert(claimed(), "must be claimed first");
475 _dc_and_los = dc_completed | (region_sz_t) live_obj_size();
476 }
477
478 // MT-unsafe claiming of a region. Should only be used during single threaded
479 // execution.
480 inline bool ParallelCompactData::RegionData::claim_unsafe()
481 {
482 if (available()) {
483 _dc_and_los |= dc_claimed;
484 return true;
485 }
486 return false;
487 }
488
489 inline void ParallelCompactData::RegionData::add_live_obj(size_t words)
490 {
491 assert(words <= (size_t)los_mask - live_obj_size(), "overflow");
492 Atomic::add((int) words, (volatile int*) &_dc_and_los);
493 }
494
495 inline void ParallelCompactData::RegionData::set_highest_ref(HeapWord* addr)
496 {
497 #ifdef ASSERT
498 HeapWord* tmp = _highest_ref;
499 while (addr > tmp) {
500 tmp = (HeapWord*)Atomic::cmpxchg_ptr(addr, &_highest_ref, tmp);
501 }
502 #endif // #ifdef ASSERT
503 }
504
505 inline bool ParallelCompactData::RegionData::claim()
506 {
507 const int los = (int) live_obj_size();
508 const int old = Atomic::cmpxchg(dc_claimed | los,
509 (volatile int*) &_dc_and_los, los);
510 return old == los;
511 }
512
513 inline ParallelCompactData::RegionData*
514 ParallelCompactData::region(size_t region_idx) const
515 {
516 assert(region_idx <= region_count(), "bad arg");
517 return _region_data + region_idx;
518 }
519
520 inline size_t
521 ParallelCompactData::region(const RegionData* const region_ptr) const
522 {
523 assert(region_ptr >= _region_data, "bad arg");
524 assert(region_ptr <= _region_data + region_count(), "bad arg");
525 return pointer_delta(region_ptr, _region_data, sizeof(RegionData));
526 }
527
528 inline size_t
529 ParallelCompactData::region_offset(const HeapWord* addr) const
530 {
531 assert(addr >= _region_start, "bad addr");
532 assert(addr <= _region_end, "bad addr");
533 return (size_t(addr) & RegionAddrOffsetMask) >> LogHeapWordSize;
534 }
535
536 inline size_t
537 ParallelCompactData::addr_to_region_idx(const HeapWord* addr) const
538 {
539 assert(addr >= _region_start, "bad addr");
540 assert(addr <= _region_end, "bad addr");
541 return pointer_delta(addr, _region_start) >> Log2RegionSize;
542 }
543
544 inline ParallelCompactData::RegionData*
545 ParallelCompactData::addr_to_region_ptr(const HeapWord* addr) const
546 {
547 return region(addr_to_region_idx(addr));
548 }
549
550 inline HeapWord*
551 ParallelCompactData::region_to_addr(size_t region) const
552 {
553 assert(region <= _region_count, "region out of range");
554 return _region_start + (region << Log2RegionSize);
555 }
556
557 inline HeapWord*
558 ParallelCompactData::region_to_addr(const RegionData* region) const
559 {
560 return region_to_addr(pointer_delta(region, _region_data,
561 sizeof(RegionData)));
562 }
563
564 inline HeapWord*
565 ParallelCompactData::region_to_addr(size_t region, size_t offset) const
566 {
567 assert(region <= _region_count, "region out of range");
568 assert(offset < RegionSize, "offset too big"); // This may be too strict.
569 return region_to_addr(region) + offset;
570 }
571
572 inline HeapWord*
573 ParallelCompactData::region_align_down(HeapWord* addr) const
574 {
575 assert(addr >= _region_start, "bad addr");
576 assert(addr < _region_end + RegionSize, "bad addr");
577 return (HeapWord*)(size_t(addr) & RegionAddrMask);
578 }
579
580 inline HeapWord*
581 ParallelCompactData::region_align_up(HeapWord* addr) const
582 {
583 assert(addr >= _region_start, "bad addr");
584 assert(addr <= _region_end, "bad addr");
585 return region_align_down(addr + RegionSizeOffsetMask);
586 }
587
588 inline bool
589 ParallelCompactData::is_region_aligned(HeapWord* addr) const
590 {
591 return region_offset(addr) == 0;
592 }
593
594 // Abstract closure for use with ParMarkBitMap::iterate(), which will invoke the
595 // do_addr() method.
596 //
597 // The closure is initialized with the number of heap words to process
598 // (words_remaining()), and becomes 'full' when it reaches 0. The do_addr()
599 // methods in subclasses should update the total as words are processed. Since
600 // only one subclass actually uses this mechanism to terminate iteration, the
601 // default initial value is > 0. The implementation is here and not in the
602 // single subclass that uses it to avoid making is_full() virtual, and thus
603 // adding a virtual call per live object.
604
605 class ParMarkBitMapClosure: public StackObj {
606 public:
607 typedef ParMarkBitMap::idx_t idx_t;
608 typedef ParMarkBitMap::IterationStatus IterationStatus;
609
610 public:
611 inline ParMarkBitMapClosure(ParMarkBitMap* mbm, ParCompactionManager* cm,
612 size_t words = max_uintx);
613
614 inline ParCompactionManager* compaction_manager() const;
615 inline ParMarkBitMap* bitmap() const;
616 inline size_t words_remaining() const;
617 inline bool is_full() const;
618 inline HeapWord* source() const;
619
620 inline void set_source(HeapWord* addr);
621
622 virtual IterationStatus do_addr(HeapWord* addr, size_t words) = 0;
623
624 protected:
625 inline void decrement_words_remaining(size_t words);
626
627 private:
628 ParMarkBitMap* const _bitmap;
629 ParCompactionManager* const _compaction_manager;
630 DEBUG_ONLY(const size_t _initial_words_remaining;) // Useful in debugger.
631 size_t _words_remaining; // Words left to copy.
632
633 protected:
634 HeapWord* _source; // Next addr that would be read.
635 };
636
637 inline
638 ParMarkBitMapClosure::ParMarkBitMapClosure(ParMarkBitMap* bitmap,
639 ParCompactionManager* cm,
640 size_t words):
641 _bitmap(bitmap), _compaction_manager(cm)
642 #ifdef ASSERT
643 , _initial_words_remaining(words)
644 #endif
645 {
646 _words_remaining = words;
647 _source = NULL;
648 }
649
650 inline ParCompactionManager* ParMarkBitMapClosure::compaction_manager() const {
651 return _compaction_manager;
652 }
653
654 inline ParMarkBitMap* ParMarkBitMapClosure::bitmap() const {
655 return _bitmap;
656 }
657
658 inline size_t ParMarkBitMapClosure::words_remaining() const {
659 return _words_remaining;
660 }
661
662 inline bool ParMarkBitMapClosure::is_full() const {
663 return words_remaining() == 0;
664 }
665
666 inline HeapWord* ParMarkBitMapClosure::source() const {
667 return _source;
668 }
669
670 inline void ParMarkBitMapClosure::set_source(HeapWord* addr) {
671 _source = addr;
672 }
673
674 inline void ParMarkBitMapClosure::decrement_words_remaining(size_t words) {
675 assert(_words_remaining >= words, "processed too many words");
676 _words_remaining -= words;
677 }
678
679 // The UseParallelOldGC collector is a stop-the-world garbage collector that
680 // does parts of the collection using parallel threads. The collection includes
681 // the tenured generation and the young generation. The permanent generation is
682 // collected at the same time as the other two generations but the permanent
683 // generation is collect by a single GC thread. The permanent generation is
684 // collected serially because of the requirement that during the processing of a
685 // klass AAA, any objects reference by AAA must already have been processed.
686 // This requirement is enforced by a left (lower address) to right (higher
687 // address) sliding compaction.
688 //
689 // There are four phases of the collection.
690 //
691 // - marking phase
692 // - summary phase
693 // - compacting phase
694 // - clean up phase
695 //
696 // Roughly speaking these phases correspond, respectively, to
697 // - mark all the live objects
698 // - calculate the destination of each object at the end of the collection
699 // - move the objects to their destination
700 // - update some references and reinitialize some variables
701 //
702 // These three phases are invoked in PSParallelCompact::invoke_no_policy(). The
703 // marking phase is implemented in PSParallelCompact::marking_phase() and does a
704 // complete marking of the heap. The summary phase is implemented in
705 // PSParallelCompact::summary_phase(). The move and update phase is implemented
706 // in PSParallelCompact::compact().
707 //
708 // A space that is being collected is divided into regions and with each region
709 // is associated an object of type ParallelCompactData. Each region is of a
710 // fixed size and typically will contain more than 1 object and may have parts
711 // of objects at the front and back of the region.
712 //
713 // region -----+---------------------+----------
714 // objects covered [ AAA )[ BBB )[ CCC )[ DDD )
715 //
716 // The marking phase does a complete marking of all live objects in the heap.
717 // The marking also compiles the size of the data for all live objects covered
718 // by the region. This size includes the part of any live object spanning onto
719 // the region (part of AAA if it is live) from the front, all live objects
720 // contained in the region (BBB and/or CCC if they are live), and the part of
721 // any live objects covered by the region that extends off the region (part of
722 // DDD if it is live). The marking phase uses multiple GC threads and marking
723 // is done in a bit array of type ParMarkBitMap. The marking of the bit map is
724 // done atomically as is the accumulation of the size of the live objects
725 // covered by a region.
726 //
727 // The summary phase calculates the total live data to the left of each region
728 // XXX. Based on that total and the bottom of the space, it can calculate the
729 // starting location of the live data in XXX. The summary phase calculates for
730 // each region XXX quantites such as
731 //
732 // - the amount of live data at the beginning of a region from an object
733 // entering the region.
734 // - the location of the first live data on the region
735 // - a count of the number of regions receiving live data from XXX.
736 //
737 // See ParallelCompactData for precise details. The summary phase also
738 // calculates the dense prefix for the compaction. The dense prefix is a
739 // portion at the beginning of the space that is not moved. The objects in the
740 // dense prefix do need to have their object references updated. See method
741 // summarize_dense_prefix().
742 //
743 // The summary phase is done using 1 GC thread.
744 //
745 // The compaction phase moves objects to their new location and updates all
746 // references in the object.
747 //
748 // A current exception is that objects that cross a region boundary are moved
749 // but do not have their references updated. References are not updated because
750 // it cannot easily be determined if the klass pointer KKK for the object AAA
751 // has been updated. KKK likely resides in a region to the left of the region
752 // containing AAA. These AAA's have there references updated at the end in a
753 // clean up phase. See the method PSParallelCompact::update_deferred_objects().
754 // An alternate strategy is being investigated for this deferral of updating.
755 //
756 // Compaction is done on a region basis. A region that is ready to be filled is
757 // put on a ready list and GC threads take region off the list and fill them. A
758 // region is ready to be filled if it empty of live objects. Such a region may
759 // have been initially empty (only contained dead objects) or may have had all
760 // its live objects copied out already. A region that compacts into itself is
761 // also ready for filling. The ready list is initially filled with empty
762 // regions and regions compacting into themselves. There is always at least 1
763 // region that can be put on the ready list. The regions are atomically added
764 // and removed from the ready list.
765
766 class PSParallelCompact : AllStatic {
767 public:
768 // Convenient access to type names.
769 typedef ParMarkBitMap::idx_t idx_t;
770 typedef ParallelCompactData::RegionData RegionData;
771
772 typedef enum {
773 perm_space_id, old_space_id, eden_space_id,
774 from_space_id, to_space_id, last_space_id
775 } SpaceId;
776
777 public:
778 // Inline closure decls
779 //
780 class IsAliveClosure: public BoolObjectClosure {
781 public:
782 virtual void do_object(oop p);
783 virtual bool do_object_b(oop p);
784 };
785
786 class KeepAliveClosure: public OopClosure {
787 private:
788 ParCompactionManager* _compaction_manager;
789 protected:
790 template <class T> inline void do_oop_work(T* p);
791 public:
792 KeepAliveClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }
793 virtual void do_oop(oop* p);
794 virtual void do_oop(narrowOop* p);
795 };
796
797 // Current unused
798 class FollowRootClosure: public OopsInGenClosure {
799 private:
800 ParCompactionManager* _compaction_manager;
801 public:
802 FollowRootClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }
803 virtual void do_oop(oop* p);
804 virtual void do_oop(narrowOop* p);
805 virtual const bool do_nmethods() const { return true; }
806 };
807
808 class FollowStackClosure: public VoidClosure {
809 private:
810 ParCompactionManager* _compaction_manager;
811 public:
812 FollowStackClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }
813 virtual void do_void();
814 };
815
816 class AdjustPointerClosure: public OopsInGenClosure {
817 private:
818 bool _is_root;
819 public:
820 AdjustPointerClosure(bool is_root) : _is_root(is_root) { }
821 virtual void do_oop(oop* p);
822 virtual void do_oop(narrowOop* p);
823 };
824
825 // Closure for verifying update of pointers. Does not
826 // have any side effects.
827 class VerifyUpdateClosure: public ParMarkBitMapClosure {
828 const MutableSpace* _space; // Is this ever used?
829
830 public:
831 VerifyUpdateClosure(ParCompactionManager* cm, const MutableSpace* sp) :
832 ParMarkBitMapClosure(PSParallelCompact::mark_bitmap(), cm), _space(sp)
833 { }
834
835 virtual IterationStatus do_addr(HeapWord* addr, size_t words);
836
837 const MutableSpace* space() { return _space; }
838 };
839
840 // Closure for updating objects altered for debug checking
841 class ResetObjectsClosure: public ParMarkBitMapClosure {
842 public:
843 ResetObjectsClosure(ParCompactionManager* cm):
844 ParMarkBitMapClosure(PSParallelCompact::mark_bitmap(), cm)
845 { }
846
847 virtual IterationStatus do_addr(HeapWord* addr, size_t words);
848 };
849
850 friend class KeepAliveClosure;
851 friend class FollowStackClosure;
852 friend class AdjustPointerClosure;
853 friend class FollowRootClosure;
854 friend class instanceKlassKlass;
855 friend class RefProcTaskProxy;
856
857 private:
858 static elapsedTimer _accumulated_time;
859 static unsigned int _total_invocations;
860 static unsigned int _maximum_compaction_gc_num;
861 static jlong _time_of_last_gc; // ms
862 static CollectorCounters* _counters;
863 static ParMarkBitMap _mark_bitmap;
864 static ParallelCompactData _summary_data;
865 static IsAliveClosure _is_alive_closure;
866 static SpaceInfo _space_info[last_space_id];
867 static bool _print_phases;
868 static AdjustPointerClosure _adjust_root_pointer_closure;
869 static AdjustPointerClosure _adjust_pointer_closure;
870
871 // Reference processing (used in ...follow_contents)
872 static ReferenceProcessor* _ref_processor;
873
874 // Updated location of intArrayKlassObj.
875 static klassOop _updated_int_array_klass_obj;
876
877 // Values computed at initialization and used by dead_wood_limiter().
878 static double _dwl_mean;
879 static double _dwl_std_dev;
880 static double _dwl_first_term;
881 static double _dwl_adjustment;
882 #ifdef ASSERT
883 static bool _dwl_initialized;
884 #endif // #ifdef ASSERT
885
886 private:
887 // Closure accessors
888 static OopClosure* adjust_pointer_closure() { return (OopClosure*)&_adjust_pointer_closure; }
889 static OopClosure* adjust_root_pointer_closure() { return (OopClosure*)&_adjust_root_pointer_closure; }
890 static BoolObjectClosure* is_alive_closure() { return (BoolObjectClosure*)&_is_alive_closure; }
891
892 static void initialize_space_info();
893
894 // Return true if details about individual phases should be printed.
895 static inline bool print_phases();
896
897 // Clear the marking bitmap and summary data that cover the specified space.
898 static void clear_data_covering_space(SpaceId id);
899
900 static void pre_compact(PreGCValues* pre_gc_values);
901 static void post_compact();
902
903 // Mark live objects
904 static void marking_phase(ParCompactionManager* cm,
905 bool maximum_heap_compaction);
906 static void follow_stack(ParCompactionManager* cm);
907 static void follow_weak_klass_links(ParCompactionManager* cm);
908
909 template <class T> static inline void adjust_pointer(T* p, bool is_root);
910 static void adjust_root_pointer(oop* p) { adjust_pointer(p, true); }
911
912 template <class T>
913 static inline void follow_root(ParCompactionManager* cm, T* p);
914
915 // Compute the dense prefix for the designated space. This is an experimental
916 // implementation currently not used in production.
917 static HeapWord* compute_dense_prefix_via_density(const SpaceId id,
918 bool maximum_compaction);
919
920 // Methods used to compute the dense prefix.
921
922 // Compute the value of the normal distribution at x = density. The mean and
923 // standard deviation are values saved by initialize_dead_wood_limiter().
924 static inline double normal_distribution(double density);
925
926 // Initialize the static vars used by dead_wood_limiter().
927 static void initialize_dead_wood_limiter();
928
929 // Return the percentage of space that can be treated as "dead wood" (i.e.,
930 // not reclaimed).
931 static double dead_wood_limiter(double density, size_t min_percent);
932
933 // Find the first (left-most) region in the range [beg, end) that has at least
934 // dead_words of dead space to the left. The argument beg must be the first
935 // region in the space that is not completely live.
936 static RegionData* dead_wood_limit_region(const RegionData* beg,
937 const RegionData* end,
938 size_t dead_words);
939
940 // Return a pointer to the first region in the range [beg, end) that is not
941 // completely full.
942 static RegionData* first_dead_space_region(const RegionData* beg,
943 const RegionData* end);
944
945 // Return a value indicating the benefit or 'yield' if the compacted region
946 // were to start (or equivalently if the dense prefix were to end) at the
947 // candidate region. Higher values are better.
948 //
949 // The value is based on the amount of space reclaimed vs. the costs of (a)
950 // updating references in the dense prefix plus (b) copying objects and
951 // updating references in the compacted region.
952 static inline double reclaimed_ratio(const RegionData* const candidate,
953 HeapWord* const bottom,
954 HeapWord* const top,
955 HeapWord* const new_top);
956
957 // Compute the dense prefix for the designated space.
958 static HeapWord* compute_dense_prefix(const SpaceId id,
959 bool maximum_compaction);
960
961 // Return true if dead space crosses onto the specified Region; bit must be
962 // the bit index corresponding to the first word of the Region.
963 static inline bool dead_space_crosses_boundary(const RegionData* region,
964 idx_t bit);
965
966 // Summary phase utility routine to fill dead space (if any) at the dense
967 // prefix boundary. Should only be called if the the dense prefix is
968 // non-empty.
969 static void fill_dense_prefix_end(SpaceId id);
970
971 // Clear the summary data source_region field for the specified addresses.
972 static void clear_source_region(HeapWord* beg_addr, HeapWord* end_addr);
973
974 #ifndef PRODUCT
975 // Routines to provoke splitting a young gen space (ParallelOldGCSplitALot).
976
977 // Fill the region [start, start + words) with live object(s). Only usable
978 // for the old and permanent generations.
979 static void fill_with_live_objects(SpaceId id, HeapWord* const start,
980 size_t words);
981 // Include the new objects in the summary data.
982 static void summarize_new_objects(SpaceId id, HeapWord* start);
983
984 // Add live objects to a survivor space since it's rare that both survivors
985 // are non-empty.
986 static void provoke_split_fill_survivor(SpaceId id);
987
988 // Add live objects and/or choose the dense prefix to provoke splitting.
989 static void provoke_split(bool & maximum_compaction);
990 #endif
991
992 static void summarize_spaces_quick();
993 static void summarize_space(SpaceId id, bool maximum_compaction);
994 static void summary_phase(ParCompactionManager* cm, bool maximum_compaction);
995
996 // Adjust addresses in roots. Does not adjust addresses in heap.
997 static void adjust_roots();
998
999 // Serial code executed in preparation for the compaction phase.
1000 static void compact_prologue();
1001
1002 // Move objects to new locations.
1003 static void compact_perm(ParCompactionManager* cm);
1004 static void compact();
1005
1006 // Add available regions to the stack and draining tasks to the task queue.
1007 static void enqueue_region_draining_tasks(GCTaskQueue* q,
1008 uint parallel_gc_threads);
1009
1010 // Add dense prefix update tasks to the task queue.
1011 static void enqueue_dense_prefix_tasks(GCTaskQueue* q,
1012 uint parallel_gc_threads);
1013
1014 // Add region stealing tasks to the task queue.
1015 static void enqueue_region_stealing_tasks(
1016 GCTaskQueue* q,
1017 ParallelTaskTerminator* terminator_ptr,
1018 uint parallel_gc_threads);
1019
1020 // For debugging only - compacts the old gen serially
1021 static void compact_serial(ParCompactionManager* cm);
1022
1023 // If objects are left in eden after a collection, try to move the boundary
1024 // and absorb them into the old gen. Returns true if eden was emptied.
1025 static bool absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
1026 PSYoungGen* young_gen,
1027 PSOldGen* old_gen);
1028
1029 // Reset time since last full gc
1030 static void reset_millis_since_last_gc();
1031
1032 protected:
1033 #ifdef VALIDATE_MARK_SWEEP
1034 static GrowableArray<void*>* _root_refs_stack;
1035 static GrowableArray<oop> * _live_oops;
1036 static GrowableArray<oop> * _live_oops_moved_to;
1037 static GrowableArray<size_t>* _live_oops_size;
1038 static size_t _live_oops_index;
1039 static size_t _live_oops_index_at_perm;
1040 static GrowableArray<void*>* _other_refs_stack;
1041 static GrowableArray<void*>* _adjusted_pointers;
1042 static bool _pointer_tracking;
1043 static bool _root_tracking;
1044
1045 // The following arrays are saved since the time of the last GC and
1046 // assist in tracking down problems where someone has done an errant
1047 // store into the heap, usually to an oop that wasn't properly
1048 // handleized across a GC. If we crash or otherwise fail before the
1049 // next GC, we can query these arrays to find out the object we had
1050 // intended to do the store to (assuming it is still alive) and the
1051 // offset within that object. Covered under RecordMarkSweepCompaction.
1052 static GrowableArray<HeapWord*> * _cur_gc_live_oops;
1053 static GrowableArray<HeapWord*> * _cur_gc_live_oops_moved_to;
1054 static GrowableArray<size_t>* _cur_gc_live_oops_size;
1055 static GrowableArray<HeapWord*> * _last_gc_live_oops;
1056 static GrowableArray<HeapWord*> * _last_gc_live_oops_moved_to;
1057 static GrowableArray<size_t>* _last_gc_live_oops_size;
1058 #endif
1059
1060 public:
1061 class MarkAndPushClosure: public OopClosure {
1062 private:
1063 ParCompactionManager* _compaction_manager;
1064 public:
1065 MarkAndPushClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }
1066 virtual void do_oop(oop* p);
1067 virtual void do_oop(narrowOop* p);
1068 virtual const bool do_nmethods() const { return true; }
1069 };
1070
1071 PSParallelCompact();
1072
1073 // Convenient accessor for Universe::heap().
1074 static ParallelScavengeHeap* gc_heap() {
1075 return (ParallelScavengeHeap*)Universe::heap();
1076 }
1077
1078 static void invoke(bool maximum_heap_compaction);
1079 static void invoke_no_policy(bool maximum_heap_compaction);
1080
1081 static void post_initialize();
1082 // Perform initialization for PSParallelCompact that requires
1083 // allocations. This should be called during the VM initialization
1084 // at a pointer where it would be appropriate to return a JNI_ENOMEM
1085 // in the event of a failure.
1086 static bool initialize();
1087
1088 // Public accessors
1089 static elapsedTimer* accumulated_time() { return &_accumulated_time; }
1090 static unsigned int total_invocations() { return _total_invocations; }
1091 static CollectorCounters* counters() { return _counters; }
1092
1093 // Used to add tasks
1094 static GCTaskManager* const gc_task_manager();
1095 static klassOop updated_int_array_klass_obj() {
1096 return _updated_int_array_klass_obj;
1097 }
1098
1099 // Marking support
1100 static inline bool mark_obj(oop obj);
1101 // Check mark and maybe push on marking stack
1102 template <class T> static inline void mark_and_push(ParCompactionManager* cm,
1103 T* p);
1104
1105 // Compaction support.
1106 // Return true if p is in the range [beg_addr, end_addr).
1107 static inline bool is_in(HeapWord* p, HeapWord* beg_addr, HeapWord* end_addr);
1108 static inline bool is_in(oop* p, HeapWord* beg_addr, HeapWord* end_addr);
1109
1110 // Convenience wrappers for per-space data kept in _space_info.
1111 static inline MutableSpace* space(SpaceId space_id);
1112 static inline HeapWord* new_top(SpaceId space_id);
1113 static inline HeapWord* dense_prefix(SpaceId space_id);
1114 static inline ObjectStartArray* start_array(SpaceId space_id);
1115
1116 // Return true if the klass should be updated.
1117 static inline bool should_update_klass(klassOop k);
1118
1119 // Move and update the live objects in the specified space.
1120 static void move_and_update(ParCompactionManager* cm, SpaceId space_id);
1121
1122 // Process the end of the given region range in the dense prefix.
1123 // This includes saving any object not updated.
1124 static void dense_prefix_regions_epilogue(ParCompactionManager* cm,
1125 size_t region_start_index,
1126 size_t region_end_index,
1127 idx_t exiting_object_offset,
1128 idx_t region_offset_start,
1129 idx_t region_offset_end);
1130
1131 // Update a region in the dense prefix. For each live object
1132 // in the region, update it's interior references. For each
1133 // dead object, fill it with deadwood. Dead space at the end
1134 // of a region range will be filled to the start of the next
1135 // live object regardless of the region_index_end. None of the
1136 // objects in the dense prefix move and dead space is dead
1137 // (holds only dead objects that don't need any processing), so
1138 // dead space can be filled in any order.
1139 static void update_and_deadwood_in_dense_prefix(ParCompactionManager* cm,
1140 SpaceId space_id,
1141 size_t region_index_start,
1142 size_t region_index_end);
1143
1144 // Return the address of the count + 1st live word in the range [beg, end).
1145 static HeapWord* skip_live_words(HeapWord* beg, HeapWord* end, size_t count);
1146
1147 // Return the address of the word to be copied to dest_addr, which must be
1148 // aligned to a region boundary.
1149 static HeapWord* first_src_addr(HeapWord* const dest_addr,
1150 SpaceId src_space_id,
1151 size_t src_region_idx);
1152
1153 // Determine the next source region, set closure.source() to the start of the
1154 // new region return the region index. Parameter end_addr is the address one
1155 // beyond the end of source range just processed. If necessary, switch to a
1156 // new source space and set src_space_id (in-out parameter) and src_space_top
1157 // (out parameter) accordingly.
1158 static size_t next_src_region(MoveAndUpdateClosure& closure,
1159 SpaceId& src_space_id,
1160 HeapWord*& src_space_top,
1161 HeapWord* end_addr);
1162
1163 // Decrement the destination count for each non-empty source region in the
1164 // range [beg_region, region(region_align_up(end_addr))). If the destination
1165 // count for a region goes to 0 and it needs to be filled, enqueue it.
1166 static void decrement_destination_counts(ParCompactionManager* cm,
1167 SpaceId src_space_id,
1168 size_t beg_region,
1169 HeapWord* end_addr);
1170
1171 // Fill a region, copying objects from one or more source regions.
1172 static void fill_region(ParCompactionManager* cm, size_t region_idx);
1173 static void fill_and_update_region(ParCompactionManager* cm, size_t region) {
1174 fill_region(cm, region);
1175 }
1176
1177 // Update the deferred objects in the space.
1178 static void update_deferred_objects(ParCompactionManager* cm, SpaceId id);
1179
1180 // Mark pointer and follow contents.
1181 template <class T>
1182 static inline void mark_and_follow(ParCompactionManager* cm, T* p);
1183
1184 static ParMarkBitMap* mark_bitmap() { return &_mark_bitmap; }
1185 static ParallelCompactData& summary_data() { return _summary_data; }
1186
1187 static inline void adjust_pointer(oop* p) { adjust_pointer(p, false); }
1188 static inline void adjust_pointer(narrowOop* p) { adjust_pointer(p, false); }
1189
1190 template <class T>
1191 static inline void adjust_pointer(T* p,
1192 HeapWord* beg_addr,
1193 HeapWord* end_addr);
1194
1195 // Reference Processing
1196 static ReferenceProcessor* const ref_processor() { return _ref_processor; }
1197
1198 // Return the SpaceId for the given address.
1199 static SpaceId space_id(HeapWord* addr);
1200
1201 // Time since last full gc (in milliseconds).
1202 static jlong millis_since_last_gc();
1203
1204 #ifdef VALIDATE_MARK_SWEEP
1205 static void track_adjusted_pointer(void* p, bool isroot);
1206 static void check_adjust_pointer(void* p);
1207 static void track_interior_pointers(oop obj);
1208 static void check_interior_pointers();
1209
1210 static void reset_live_oop_tracking(bool at_perm);
1211 static void register_live_oop(oop p, size_t size);
1212 static void validate_live_oop(oop p, size_t size);
1213 static void live_oop_moved_to(HeapWord* q, size_t size, HeapWord* compaction_top);
1214 static void compaction_complete();
1215
1216 // Querying operation of RecordMarkSweepCompaction results.
1217 // Finds and prints the current base oop and offset for a word
1218 // within an oop that was live during the last GC. Helpful for
1219 // tracking down heap stomps.
1220 static void print_new_location_of_heap_address(HeapWord* q);
1221 #endif // #ifdef VALIDATE_MARK_SWEEP
1222
1223 // Call backs for class unloading
1224 // Update subklass/sibling/implementor links at end of marking.
1225 static void revisit_weak_klass_link(ParCompactionManager* cm, Klass* k);
1226
1227 #ifndef PRODUCT
1228 // Debugging support.
1229 static const char* space_names[last_space_id];
1230 static void print_region_ranges();
1231 static void print_dense_prefix_stats(const char* const algorithm,
1232 const SpaceId id,
1233 const bool maximum_compaction,
1234 HeapWord* const addr);
1235 static void summary_phase_msg(SpaceId dst_space_id,
1236 HeapWord* dst_beg, HeapWord* dst_end,
1237 SpaceId src_space_id,
1238 HeapWord* src_beg, HeapWord* src_end);
1239 #endif // #ifndef PRODUCT
1240
1241 #ifdef ASSERT
1242 // Sanity check the new location of a word in the heap.
1243 static inline void check_new_location(HeapWord* old_addr, HeapWord* new_addr);
1244 // Verify that all the regions have been emptied.
1245 static void verify_complete(SpaceId space_id);
1246 #endif // #ifdef ASSERT
1247 };
1248
1249 inline bool PSParallelCompact::mark_obj(oop obj) {
1250 const int obj_size = obj->size();
1251 if (mark_bitmap()->mark_obj(obj, obj_size)) {
1252 _summary_data.add_obj(obj, obj_size);
1253 return true;
1254 } else {
1255 return false;
1256 }
1257 }
1258
1259 template <class T>
1260 inline void PSParallelCompact::follow_root(ParCompactionManager* cm, T* p) {
1261 assert(!Universe::heap()->is_in_reserved(p),
1262 "roots shouldn't be things within the heap");
1263 #ifdef VALIDATE_MARK_SWEEP
1264 if (ValidateMarkSweep) {
1265 guarantee(!_root_refs_stack->contains(p), "should only be in here once");
1266 _root_refs_stack->push(p);
1267 }
1268 #endif
1269 T heap_oop = oopDesc::load_heap_oop(p);
1270 if (!oopDesc::is_null(heap_oop)) {
1271 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
1272 if (mark_bitmap()->is_unmarked(obj)) {
1273 if (mark_obj(obj)) {
1274 obj->follow_contents(cm);
1275 }
1276 }
1277 }
1278 follow_stack(cm);
1279 }
1280
1281 template <class T>
1282 inline void PSParallelCompact::mark_and_follow(ParCompactionManager* cm,
1283 T* p) {
1284 T heap_oop = oopDesc::load_heap_oop(p);
1285 if (!oopDesc::is_null(heap_oop)) {
1286 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
1287 if (mark_bitmap()->is_unmarked(obj)) {
1288 if (mark_obj(obj)) {
1289 obj->follow_contents(cm);
1290 }
1291 }
1292 }
1293 }
1294
1295 template <class T>
1296 inline void PSParallelCompact::mark_and_push(ParCompactionManager* cm, T* p) {
1297 T heap_oop = oopDesc::load_heap_oop(p);
1298 if (!oopDesc::is_null(heap_oop)) {
1299 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
1300 if (mark_bitmap()->is_unmarked(obj)) {
1301 if (mark_obj(obj)) {
1302 // This thread marked the object and owns the subsequent processing of it.
1303 cm->save_for_scanning(obj);
1304 }
1305 }
1306 }
1307 }
1308
1309 template <class T>
1310 inline void PSParallelCompact::adjust_pointer(T* p, bool isroot) {
1311 T heap_oop = oopDesc::load_heap_oop(p);
1312 if (!oopDesc::is_null(heap_oop)) {
1313 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
1314 oop new_obj = (oop)summary_data().calc_new_pointer(obj);
1315 assert(new_obj != NULL || // is forwarding ptr?
1316 obj->is_shared(), // never forwarded?
1317 "should be forwarded");
1318 // Just always do the update unconditionally?
1319 if (new_obj != NULL) {
1320 assert(Universe::heap()->is_in_reserved(new_obj),
1321 "should be in object space");
1322 oopDesc::encode_store_heap_oop_not_null(p, new_obj);
1323 }
1324 }
1325 VALIDATE_MARK_SWEEP_ONLY(track_adjusted_pointer(p, isroot));
1326 }
1327
1328 template <class T>
1329 inline void PSParallelCompact::KeepAliveClosure::do_oop_work(T* p) {
1330 #ifdef VALIDATE_MARK_SWEEP
1331 if (ValidateMarkSweep) {
1332 if (!Universe::heap()->is_in_reserved(p)) {
1333 _root_refs_stack->push(p);
1334 } else {
1335 _other_refs_stack->push(p);
1336 }
1337 }
1338 #endif
1339 mark_and_push(_compaction_manager, p);
1340 }
1341
1342 inline bool PSParallelCompact::print_phases() {
1343 return _print_phases;
1344 }
1345
1346 inline double PSParallelCompact::normal_distribution(double density) {
1347 assert(_dwl_initialized, "uninitialized");
1348 const double squared_term = (density - _dwl_mean) / _dwl_std_dev;
1349 return _dwl_first_term * exp(-0.5 * squared_term * squared_term);
1350 }
1351
1352 inline bool
1353 PSParallelCompact::dead_space_crosses_boundary(const RegionData* region,
1354 idx_t bit)
1355 {
1356 assert(bit > 0, "cannot call this for the first bit/region");
1357 assert(_summary_data.region_to_addr(region) == _mark_bitmap.bit_to_addr(bit),
1358 "sanity check");
1359
1360 // Dead space crosses the boundary if (1) a partial object does not extend
1361 // onto the region, (2) an object does not start at the beginning of the
1362 // region, and (3) an object does not end at the end of the prior region.
1363 return region->partial_obj_size() == 0 &&
1364 !_mark_bitmap.is_obj_beg(bit) &&
1365 !_mark_bitmap.is_obj_end(bit - 1);
1366 }
1367
1368 inline bool
1369 PSParallelCompact::is_in(HeapWord* p, HeapWord* beg_addr, HeapWord* end_addr) {
1370 return p >= beg_addr && p < end_addr;
1371 }
1372
1373 inline bool
1374 PSParallelCompact::is_in(oop* p, HeapWord* beg_addr, HeapWord* end_addr) {
1375 return is_in((HeapWord*)p, beg_addr, end_addr);
1376 }
1377
1378 inline MutableSpace* PSParallelCompact::space(SpaceId id) {
1379 assert(id < last_space_id, "id out of range");
1380 return _space_info[id].space();
1381 }
1382
1383 inline HeapWord* PSParallelCompact::new_top(SpaceId id) {
1384 assert(id < last_space_id, "id out of range");
1385 return _space_info[id].new_top();
1386 }
1387
1388 inline HeapWord* PSParallelCompact::dense_prefix(SpaceId id) {
1389 assert(id < last_space_id, "id out of range");
1390 return _space_info[id].dense_prefix();
1391 }
1392
1393 inline ObjectStartArray* PSParallelCompact::start_array(SpaceId id) {
1394 assert(id < last_space_id, "id out of range");
1395 return _space_info[id].start_array();
1396 }
1397
1398 inline bool PSParallelCompact::should_update_klass(klassOop k) {
1399 return ((HeapWord*) k) >= dense_prefix(perm_space_id);
1400 }
1401
1402 template <class T>
1403 inline void PSParallelCompact::adjust_pointer(T* p,
1404 HeapWord* beg_addr,
1405 HeapWord* end_addr) {
1406 if (is_in((HeapWord*)p, beg_addr, end_addr)) {
1407 adjust_pointer(p);
1408 }
1409 }
1410
1411 #ifdef ASSERT
1412 inline void
1413 PSParallelCompact::check_new_location(HeapWord* old_addr, HeapWord* new_addr)
1414 {
1415 assert(old_addr >= new_addr || space_id(old_addr) != space_id(new_addr),
1416 "must move left or to a different space");
1417 }
1418 #endif // ASSERT
1419
1420 class MoveAndUpdateClosure: public ParMarkBitMapClosure {
1421 public:
1422 inline MoveAndUpdateClosure(ParMarkBitMap* bitmap, ParCompactionManager* cm,
1423 ObjectStartArray* start_array,
1424 HeapWord* destination, size_t words);
1425
1426 // Accessors.
1427 HeapWord* destination() const { return _destination; }
1428
1429 // If the object will fit (size <= words_remaining()), copy it to the current
1430 // destination, update the interior oops and the start array and return either
1431 // full (if the closure is full) or incomplete. If the object will not fit,
1432 // return would_overflow.
1433 virtual IterationStatus do_addr(HeapWord* addr, size_t size);
1434
1435 // Copy enough words to fill this closure, starting at source(). Interior
1436 // oops and the start array are not updated. Return full.
1437 IterationStatus copy_until_full();
1438
1439 // Copy enough words to fill this closure or to the end of an object,
1440 // whichever is smaller, starting at source(). Interior oops and the start
1441 // array are not updated.
1442 void copy_partial_obj();
1443
1444 protected:
1445 // Update variables to indicate that word_count words were processed.
1446 inline void update_state(size_t word_count);
1447
1448 protected:
1449 ObjectStartArray* const _start_array;
1450 HeapWord* _destination; // Next addr to be written.
1451 };
1452
1453 inline
1454 MoveAndUpdateClosure::MoveAndUpdateClosure(ParMarkBitMap* bitmap,
1455 ParCompactionManager* cm,
1456 ObjectStartArray* start_array,
1457 HeapWord* destination,
1458 size_t words) :
1459 ParMarkBitMapClosure(bitmap, cm, words), _start_array(start_array)
1460 {
1461 _destination = destination;
1462 }
1463
1464 inline void MoveAndUpdateClosure::update_state(size_t words)
1465 {
1466 decrement_words_remaining(words);
1467 _source += words;
1468 _destination += words;
1469 }
1470
1471 class UpdateOnlyClosure: public ParMarkBitMapClosure {
1472 private:
1473 const PSParallelCompact::SpaceId _space_id;
1474 ObjectStartArray* const _start_array;
1475
1476 public:
1477 UpdateOnlyClosure(ParMarkBitMap* mbm,
1478 ParCompactionManager* cm,
1479 PSParallelCompact::SpaceId space_id);
1480
1481 // Update the object.
1482 virtual IterationStatus do_addr(HeapWord* addr, size_t words);
1483
1484 inline void do_addr(HeapWord* addr);
1485 };
1486
1487 inline void UpdateOnlyClosure::do_addr(HeapWord* addr)
1488 {
1489 _start_array->allocate_block(addr);
1490 oop(addr)->update_contents(compaction_manager());
1491 }
1492
1493 class FillClosure: public ParMarkBitMapClosure
1494 {
1495 public:
1496 FillClosure(ParCompactionManager* cm, PSParallelCompact::SpaceId space_id) :
1497 ParMarkBitMapClosure(PSParallelCompact::mark_bitmap(), cm),
1498 _start_array(PSParallelCompact::start_array(space_id))
1499 {
1500 assert(space_id == PSParallelCompact::perm_space_id ||
1501 space_id == PSParallelCompact::old_space_id,
1502 "cannot use FillClosure in the young gen");
1503 }
1504
1505 virtual IterationStatus do_addr(HeapWord* addr, size_t size) {
1506 CollectedHeap::fill_with_objects(addr, size);
1507 HeapWord* const end = addr + size;
1508 do {
1509 _start_array->allocate_block(addr);
1510 addr += oop(addr)->size();
1511 } while (addr < end);
1512 return ParMarkBitMap::incomplete;
1513 }
1514
1515 private:
1516 ObjectStartArray* const _start_array;
1517 };