Thu, 16 Feb 2012 13:12:25 -0800
7146343: PS invoke methods should indicate the type of gc done
Reviewed-by: stefank, jmasa
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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25 #ifndef SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSPARALLELCOMPACT_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSPARALLELCOMPACT_HPP
28 #include "gc_implementation/parallelScavenge/objectStartArray.hpp"
29 #include "gc_implementation/parallelScavenge/parMarkBitMap.hpp"
30 #include "gc_implementation/parallelScavenge/psCompactionManager.hpp"
31 #include "gc_implementation/shared/collectorCounters.hpp"
32 #include "gc_implementation/shared/markSweep.hpp"
33 #include "gc_implementation/shared/mutableSpace.hpp"
34 #include "memory/sharedHeap.hpp"
35 #include "oops/oop.hpp"
37 class ParallelScavengeHeap;
38 class PSAdaptiveSizePolicy;
39 class PSYoungGen;
40 class PSOldGen;
41 class PSPermGen;
42 class ParCompactionManager;
43 class ParallelTaskTerminator;
44 class PSParallelCompact;
45 class GCTaskManager;
46 class GCTaskQueue;
47 class PreGCValues;
48 class MoveAndUpdateClosure;
49 class RefProcTaskExecutor;
51 // The SplitInfo class holds the information needed to 'split' a source region
52 // so that the live data can be copied to two destination *spaces*. Normally,
53 // all the live data in a region is copied to a single destination space (e.g.,
54 // everything live in a region in eden is copied entirely into the old gen).
55 // However, when the heap is nearly full, all the live data in eden may not fit
56 // into the old gen. Copying only some of the regions from eden to old gen
57 // requires finding a region that does not contain a partial object (i.e., no
58 // live object crosses the region boundary) somewhere near the last object that
59 // does fit into the old gen. Since it's not always possible to find such a
60 // region, splitting is necessary for predictable behavior.
61 //
62 // A region is always split at the end of the partial object. This avoids
63 // additional tests when calculating the new location of a pointer, which is a
64 // very hot code path. The partial object and everything to its left will be
65 // copied to another space (call it dest_space_1). The live data to the right
66 // of the partial object will be copied either within the space itself, or to a
67 // different destination space (distinct from dest_space_1).
68 //
69 // Split points are identified during the summary phase, when region
70 // destinations are computed: data about the split, including the
71 // partial_object_size, is recorded in a SplitInfo record and the
72 // partial_object_size field in the summary data is set to zero. The zeroing is
73 // possible (and necessary) since the partial object will move to a different
74 // destination space than anything to its right, thus the partial object should
75 // not affect the locations of any objects to its right.
76 //
77 // The recorded data is used during the compaction phase, but only rarely: when
78 // the partial object on the split region will be copied across a destination
79 // region boundary. This test is made once each time a region is filled, and is
80 // a simple address comparison, so the overhead is negligible (see
81 // PSParallelCompact::first_src_addr()).
82 //
83 // Notes:
84 //
85 // Only regions with partial objects are split; a region without a partial
86 // object does not need any extra bookkeeping.
87 //
88 // At most one region is split per space, so the amount of data required is
89 // constant.
90 //
91 // A region is split only when the destination space would overflow. Once that
92 // happens, the destination space is abandoned and no other data (even from
93 // other source spaces) is targeted to that destination space. Abandoning the
94 // destination space may leave a somewhat large unused area at the end, if a
95 // large object caused the overflow.
96 //
97 // Future work:
98 //
99 // More bookkeeping would be required to continue to use the destination space.
100 // The most general solution would allow data from regions in two different
101 // source spaces to be "joined" in a single destination region. At the very
102 // least, additional code would be required in next_src_region() to detect the
103 // join and skip to an out-of-order source region. If the join region was also
104 // the last destination region to which a split region was copied (the most
105 // likely case), then additional work would be needed to get fill_region() to
106 // stop iteration and switch to a new source region at the right point. Basic
107 // idea would be to use a fake value for the top of the source space. It is
108 // doable, if a bit tricky.
109 //
110 // A simpler (but less general) solution would fill the remainder of the
111 // destination region with a dummy object and continue filling the next
112 // destination region.
114 class SplitInfo
115 {
116 public:
117 // Return true if this split info is valid (i.e., if a split has been
118 // recorded). The very first region cannot have a partial object and thus is
119 // never split, so 0 is the 'invalid' value.
120 bool is_valid() const { return _src_region_idx > 0; }
122 // Return true if this split holds data for the specified source region.
123 inline bool is_split(size_t source_region) const;
125 // The index of the split region, the size of the partial object on that
126 // region and the destination of the partial object.
127 size_t src_region_idx() const { return _src_region_idx; }
128 size_t partial_obj_size() const { return _partial_obj_size; }
129 HeapWord* destination() const { return _destination; }
131 // The destination count of the partial object referenced by this split
132 // (either 1 or 2). This must be added to the destination count of the
133 // remainder of the source region.
134 unsigned int destination_count() const { return _destination_count; }
136 // If a word within the partial object will be written to the first word of a
137 // destination region, this is the address of the destination region;
138 // otherwise this is NULL.
139 HeapWord* dest_region_addr() const { return _dest_region_addr; }
141 // If a word within the partial object will be written to the first word of a
142 // destination region, this is the address of that word within the partial
143 // object; otherwise this is NULL.
144 HeapWord* first_src_addr() const { return _first_src_addr; }
146 // Record the data necessary to split the region src_region_idx.
147 void record(size_t src_region_idx, size_t partial_obj_size,
148 HeapWord* destination);
150 void clear();
152 DEBUG_ONLY(void verify_clear();)
154 private:
155 size_t _src_region_idx;
156 size_t _partial_obj_size;
157 HeapWord* _destination;
158 unsigned int _destination_count;
159 HeapWord* _dest_region_addr;
160 HeapWord* _first_src_addr;
161 };
163 inline bool SplitInfo::is_split(size_t region_idx) const
164 {
165 return _src_region_idx == region_idx && is_valid();
166 }
168 class SpaceInfo
169 {
170 public:
171 MutableSpace* space() const { return _space; }
173 // Where the free space will start after the collection. Valid only after the
174 // summary phase completes.
175 HeapWord* new_top() const { return _new_top; }
177 // Allows new_top to be set.
178 HeapWord** new_top_addr() { return &_new_top; }
180 // Where the smallest allowable dense prefix ends (used only for perm gen).
181 HeapWord* min_dense_prefix() const { return _min_dense_prefix; }
183 // Where the dense prefix ends, or the compacted region begins.
184 HeapWord* dense_prefix() const { return _dense_prefix; }
186 // The start array for the (generation containing the) space, or NULL if there
187 // is no start array.
188 ObjectStartArray* start_array() const { return _start_array; }
190 SplitInfo& split_info() { return _split_info; }
192 void set_space(MutableSpace* s) { _space = s; }
193 void set_new_top(HeapWord* addr) { _new_top = addr; }
194 void set_min_dense_prefix(HeapWord* addr) { _min_dense_prefix = addr; }
195 void set_dense_prefix(HeapWord* addr) { _dense_prefix = addr; }
196 void set_start_array(ObjectStartArray* s) { _start_array = s; }
198 void publish_new_top() const { _space->set_top(_new_top); }
200 private:
201 MutableSpace* _space;
202 HeapWord* _new_top;
203 HeapWord* _min_dense_prefix;
204 HeapWord* _dense_prefix;
205 ObjectStartArray* _start_array;
206 SplitInfo _split_info;
207 };
209 class ParallelCompactData
210 {
211 public:
212 // Sizes are in HeapWords, unless indicated otherwise.
213 static const size_t Log2RegionSize;
214 static const size_t RegionSize;
215 static const size_t RegionSizeBytes;
217 // Mask for the bits in a size_t to get an offset within a region.
218 static const size_t RegionSizeOffsetMask;
219 // Mask for the bits in a pointer to get an offset within a region.
220 static const size_t RegionAddrOffsetMask;
221 // Mask for the bits in a pointer to get the address of the start of a region.
222 static const size_t RegionAddrMask;
224 class RegionData
225 {
226 public:
227 // Destination address of the region.
228 HeapWord* destination() const { return _destination; }
230 // The first region containing data destined for this region.
231 size_t source_region() const { return _source_region; }
233 // The object (if any) starting in this region and ending in a different
234 // region that could not be updated during the main (parallel) compaction
235 // phase. This is different from _partial_obj_addr, which is an object that
236 // extends onto a source region. However, the two uses do not overlap in
237 // time, so the same field is used to save space.
238 HeapWord* deferred_obj_addr() const { return _partial_obj_addr; }
240 // The starting address of the partial object extending onto the region.
241 HeapWord* partial_obj_addr() const { return _partial_obj_addr; }
243 // Size of the partial object extending onto the region (words).
244 size_t partial_obj_size() const { return _partial_obj_size; }
246 // Size of live data that lies within this region due to objects that start
247 // in this region (words). This does not include the partial object
248 // extending onto the region (if any), or the part of an object that extends
249 // onto the next region (if any).
250 size_t live_obj_size() const { return _dc_and_los & los_mask; }
252 // Total live data that lies within the region (words).
253 size_t data_size() const { return partial_obj_size() + live_obj_size(); }
255 // The destination_count is the number of other regions to which data from
256 // this region will be copied. At the end of the summary phase, the valid
257 // values of destination_count are
258 //
259 // 0 - data from the region will be compacted completely into itself, or the
260 // region is empty. The region can be claimed and then filled.
261 // 1 - data from the region will be compacted into 1 other region; some
262 // data from the region may also be compacted into the region itself.
263 // 2 - data from the region will be copied to 2 other regions.
264 //
265 // During compaction as regions are emptied, the destination_count is
266 // decremented (atomically) and when it reaches 0, it can be claimed and
267 // then filled.
268 //
269 // A region is claimed for processing by atomically changing the
270 // destination_count to the claimed value (dc_claimed). After a region has
271 // been filled, the destination_count should be set to the completed value
272 // (dc_completed).
273 inline uint destination_count() const;
274 inline uint destination_count_raw() const;
276 // The location of the java heap data that corresponds to this region.
277 inline HeapWord* data_location() const;
279 // The highest address referenced by objects in this region.
280 inline HeapWord* highest_ref() const;
282 // Whether this region is available to be claimed, has been claimed, or has
283 // been completed.
284 //
285 // Minor subtlety: claimed() returns true if the region is marked
286 // completed(), which is desirable since a region must be claimed before it
287 // can be completed.
288 bool available() const { return _dc_and_los < dc_one; }
289 bool claimed() const { return _dc_and_los >= dc_claimed; }
290 bool completed() const { return _dc_and_los >= dc_completed; }
292 // These are not atomic.
293 void set_destination(HeapWord* addr) { _destination = addr; }
294 void set_source_region(size_t region) { _source_region = region; }
295 void set_deferred_obj_addr(HeapWord* addr) { _partial_obj_addr = addr; }
296 void set_partial_obj_addr(HeapWord* addr) { _partial_obj_addr = addr; }
297 void set_partial_obj_size(size_t words) {
298 _partial_obj_size = (region_sz_t) words;
299 }
301 inline void set_destination_count(uint count);
302 inline void set_live_obj_size(size_t words);
303 inline void set_data_location(HeapWord* addr);
304 inline void set_completed();
305 inline bool claim_unsafe();
307 // These are atomic.
308 inline void add_live_obj(size_t words);
309 inline void set_highest_ref(HeapWord* addr);
310 inline void decrement_destination_count();
311 inline bool claim();
313 private:
314 // The type used to represent object sizes within a region.
315 typedef uint region_sz_t;
317 // Constants for manipulating the _dc_and_los field, which holds both the
318 // destination count and live obj size. The live obj size lives at the
319 // least significant end so no masking is necessary when adding.
320 static const region_sz_t dc_shift; // Shift amount.
321 static const region_sz_t dc_mask; // Mask for destination count.
322 static const region_sz_t dc_one; // 1, shifted appropriately.
323 static const region_sz_t dc_claimed; // Region has been claimed.
324 static const region_sz_t dc_completed; // Region has been completed.
325 static const region_sz_t los_mask; // Mask for live obj size.
327 HeapWord* _destination;
328 size_t _source_region;
329 HeapWord* _partial_obj_addr;
330 region_sz_t _partial_obj_size;
331 region_sz_t volatile _dc_and_los;
332 #ifdef ASSERT
333 // These enable optimizations that are only partially implemented. Use
334 // debug builds to prevent the code fragments from breaking.
335 HeapWord* _data_location;
336 HeapWord* _highest_ref;
337 #endif // #ifdef ASSERT
339 #ifdef ASSERT
340 public:
341 uint _pushed; // 0 until region is pushed onto a worker's stack
342 private:
343 #endif
344 };
346 public:
347 ParallelCompactData();
348 bool initialize(MemRegion covered_region);
350 size_t region_count() const { return _region_count; }
352 // Convert region indices to/from RegionData pointers.
353 inline RegionData* region(size_t region_idx) const;
354 inline size_t region(const RegionData* const region_ptr) const;
356 // Returns true if the given address is contained within the region
357 bool region_contains(size_t region_index, HeapWord* addr);
359 void add_obj(HeapWord* addr, size_t len);
360 void add_obj(oop p, size_t len) { add_obj((HeapWord*)p, len); }
362 // Fill in the regions covering [beg, end) so that no data moves; i.e., the
363 // destination of region n is simply the start of region n. The argument beg
364 // must be region-aligned; end need not be.
365 void summarize_dense_prefix(HeapWord* beg, HeapWord* end);
367 HeapWord* summarize_split_space(size_t src_region, SplitInfo& split_info,
368 HeapWord* destination, HeapWord* target_end,
369 HeapWord** target_next);
370 bool summarize(SplitInfo& split_info,
371 HeapWord* source_beg, HeapWord* source_end,
372 HeapWord** source_next,
373 HeapWord* target_beg, HeapWord* target_end,
374 HeapWord** target_next);
376 void clear();
377 void clear_range(size_t beg_region, size_t end_region);
378 void clear_range(HeapWord* beg, HeapWord* end) {
379 clear_range(addr_to_region_idx(beg), addr_to_region_idx(end));
380 }
382 // Return the number of words between addr and the start of the region
383 // containing addr.
384 inline size_t region_offset(const HeapWord* addr) const;
386 // Convert addresses to/from a region index or region pointer.
387 inline size_t addr_to_region_idx(const HeapWord* addr) const;
388 inline RegionData* addr_to_region_ptr(const HeapWord* addr) const;
389 inline HeapWord* region_to_addr(size_t region) const;
390 inline HeapWord* region_to_addr(size_t region, size_t offset) const;
391 inline HeapWord* region_to_addr(const RegionData* region) const;
393 inline HeapWord* region_align_down(HeapWord* addr) const;
394 inline HeapWord* region_align_up(HeapWord* addr) const;
395 inline bool is_region_aligned(HeapWord* addr) const;
397 // Return the address one past the end of the partial object.
398 HeapWord* partial_obj_end(size_t region_idx) const;
400 // Return the new location of the object p after the
401 // the compaction.
402 HeapWord* calc_new_pointer(HeapWord* addr);
404 HeapWord* calc_new_pointer(oop p) {
405 return calc_new_pointer((HeapWord*) p);
406 }
408 // Return the updated address for the given klass
409 klassOop calc_new_klass(klassOop);
411 #ifdef ASSERT
412 void verify_clear(const PSVirtualSpace* vspace);
413 void verify_clear();
414 #endif // #ifdef ASSERT
416 private:
417 bool initialize_region_data(size_t region_size);
418 PSVirtualSpace* create_vspace(size_t count, size_t element_size);
420 private:
421 HeapWord* _region_start;
422 #ifdef ASSERT
423 HeapWord* _region_end;
424 #endif // #ifdef ASSERT
426 PSVirtualSpace* _region_vspace;
427 RegionData* _region_data;
428 size_t _region_count;
429 };
431 inline uint
432 ParallelCompactData::RegionData::destination_count_raw() const
433 {
434 return _dc_and_los & dc_mask;
435 }
437 inline uint
438 ParallelCompactData::RegionData::destination_count() const
439 {
440 return destination_count_raw() >> dc_shift;
441 }
443 inline void
444 ParallelCompactData::RegionData::set_destination_count(uint count)
445 {
446 assert(count <= (dc_completed >> dc_shift), "count too large");
447 const region_sz_t live_sz = (region_sz_t) live_obj_size();
448 _dc_and_los = (count << dc_shift) | live_sz;
449 }
451 inline void ParallelCompactData::RegionData::set_live_obj_size(size_t words)
452 {
453 assert(words <= los_mask, "would overflow");
454 _dc_and_los = destination_count_raw() | (region_sz_t)words;
455 }
457 inline void ParallelCompactData::RegionData::decrement_destination_count()
458 {
459 assert(_dc_and_los < dc_claimed, "already claimed");
460 assert(_dc_and_los >= dc_one, "count would go negative");
461 Atomic::add((int)dc_mask, (volatile int*)&_dc_and_los);
462 }
464 inline HeapWord* ParallelCompactData::RegionData::data_location() const
465 {
466 DEBUG_ONLY(return _data_location;)
467 NOT_DEBUG(return NULL;)
468 }
470 inline HeapWord* ParallelCompactData::RegionData::highest_ref() const
471 {
472 DEBUG_ONLY(return _highest_ref;)
473 NOT_DEBUG(return NULL;)
474 }
476 inline void ParallelCompactData::RegionData::set_data_location(HeapWord* addr)
477 {
478 DEBUG_ONLY(_data_location = addr;)
479 }
481 inline void ParallelCompactData::RegionData::set_completed()
482 {
483 assert(claimed(), "must be claimed first");
484 _dc_and_los = dc_completed | (region_sz_t) live_obj_size();
485 }
487 // MT-unsafe claiming of a region. Should only be used during single threaded
488 // execution.
489 inline bool ParallelCompactData::RegionData::claim_unsafe()
490 {
491 if (available()) {
492 _dc_and_los |= dc_claimed;
493 return true;
494 }
495 return false;
496 }
498 inline void ParallelCompactData::RegionData::add_live_obj(size_t words)
499 {
500 assert(words <= (size_t)los_mask - live_obj_size(), "overflow");
501 Atomic::add((int) words, (volatile int*) &_dc_and_los);
502 }
504 inline void ParallelCompactData::RegionData::set_highest_ref(HeapWord* addr)
505 {
506 #ifdef ASSERT
507 HeapWord* tmp = _highest_ref;
508 while (addr > tmp) {
509 tmp = (HeapWord*)Atomic::cmpxchg_ptr(addr, &_highest_ref, tmp);
510 }
511 #endif // #ifdef ASSERT
512 }
514 inline bool ParallelCompactData::RegionData::claim()
515 {
516 const int los = (int) live_obj_size();
517 const int old = Atomic::cmpxchg(dc_claimed | los,
518 (volatile int*) &_dc_and_los, los);
519 return old == los;
520 }
522 inline ParallelCompactData::RegionData*
523 ParallelCompactData::region(size_t region_idx) const
524 {
525 assert(region_idx <= region_count(), "bad arg");
526 return _region_data + region_idx;
527 }
529 inline size_t
530 ParallelCompactData::region(const RegionData* const region_ptr) const
531 {
532 assert(region_ptr >= _region_data, "bad arg");
533 assert(region_ptr <= _region_data + region_count(), "bad arg");
534 return pointer_delta(region_ptr, _region_data, sizeof(RegionData));
535 }
537 inline size_t
538 ParallelCompactData::region_offset(const HeapWord* addr) const
539 {
540 assert(addr >= _region_start, "bad addr");
541 assert(addr <= _region_end, "bad addr");
542 return (size_t(addr) & RegionAddrOffsetMask) >> LogHeapWordSize;
543 }
545 inline size_t
546 ParallelCompactData::addr_to_region_idx(const HeapWord* addr) const
547 {
548 assert(addr >= _region_start, "bad addr");
549 assert(addr <= _region_end, "bad addr");
550 return pointer_delta(addr, _region_start) >> Log2RegionSize;
551 }
553 inline ParallelCompactData::RegionData*
554 ParallelCompactData::addr_to_region_ptr(const HeapWord* addr) const
555 {
556 return region(addr_to_region_idx(addr));
557 }
559 inline HeapWord*
560 ParallelCompactData::region_to_addr(size_t region) const
561 {
562 assert(region <= _region_count, "region out of range");
563 return _region_start + (region << Log2RegionSize);
564 }
566 inline HeapWord*
567 ParallelCompactData::region_to_addr(const RegionData* region) const
568 {
569 return region_to_addr(pointer_delta(region, _region_data,
570 sizeof(RegionData)));
571 }
573 inline HeapWord*
574 ParallelCompactData::region_to_addr(size_t region, size_t offset) const
575 {
576 assert(region <= _region_count, "region out of range");
577 assert(offset < RegionSize, "offset too big"); // This may be too strict.
578 return region_to_addr(region) + offset;
579 }
581 inline HeapWord*
582 ParallelCompactData::region_align_down(HeapWord* addr) const
583 {
584 assert(addr >= _region_start, "bad addr");
585 assert(addr < _region_end + RegionSize, "bad addr");
586 return (HeapWord*)(size_t(addr) & RegionAddrMask);
587 }
589 inline HeapWord*
590 ParallelCompactData::region_align_up(HeapWord* addr) const
591 {
592 assert(addr >= _region_start, "bad addr");
593 assert(addr <= _region_end, "bad addr");
594 return region_align_down(addr + RegionSizeOffsetMask);
595 }
597 inline bool
598 ParallelCompactData::is_region_aligned(HeapWord* addr) const
599 {
600 return region_offset(addr) == 0;
601 }
603 // Abstract closure for use with ParMarkBitMap::iterate(), which will invoke the
604 // do_addr() method.
605 //
606 // The closure is initialized with the number of heap words to process
607 // (words_remaining()), and becomes 'full' when it reaches 0. The do_addr()
608 // methods in subclasses should update the total as words are processed. Since
609 // only one subclass actually uses this mechanism to terminate iteration, the
610 // default initial value is > 0. The implementation is here and not in the
611 // single subclass that uses it to avoid making is_full() virtual, and thus
612 // adding a virtual call per live object.
614 class ParMarkBitMapClosure: public StackObj {
615 public:
616 typedef ParMarkBitMap::idx_t idx_t;
617 typedef ParMarkBitMap::IterationStatus IterationStatus;
619 public:
620 inline ParMarkBitMapClosure(ParMarkBitMap* mbm, ParCompactionManager* cm,
621 size_t words = max_uintx);
623 inline ParCompactionManager* compaction_manager() const;
624 inline ParMarkBitMap* bitmap() const;
625 inline size_t words_remaining() const;
626 inline bool is_full() const;
627 inline HeapWord* source() const;
629 inline void set_source(HeapWord* addr);
631 virtual IterationStatus do_addr(HeapWord* addr, size_t words) = 0;
633 protected:
634 inline void decrement_words_remaining(size_t words);
636 private:
637 ParMarkBitMap* const _bitmap;
638 ParCompactionManager* const _compaction_manager;
639 DEBUG_ONLY(const size_t _initial_words_remaining;) // Useful in debugger.
640 size_t _words_remaining; // Words left to copy.
642 protected:
643 HeapWord* _source; // Next addr that would be read.
644 };
646 inline
647 ParMarkBitMapClosure::ParMarkBitMapClosure(ParMarkBitMap* bitmap,
648 ParCompactionManager* cm,
649 size_t words):
650 _bitmap(bitmap), _compaction_manager(cm)
651 #ifdef ASSERT
652 , _initial_words_remaining(words)
653 #endif
654 {
655 _words_remaining = words;
656 _source = NULL;
657 }
659 inline ParCompactionManager* ParMarkBitMapClosure::compaction_manager() const {
660 return _compaction_manager;
661 }
663 inline ParMarkBitMap* ParMarkBitMapClosure::bitmap() const {
664 return _bitmap;
665 }
667 inline size_t ParMarkBitMapClosure::words_remaining() const {
668 return _words_remaining;
669 }
671 inline bool ParMarkBitMapClosure::is_full() const {
672 return words_remaining() == 0;
673 }
675 inline HeapWord* ParMarkBitMapClosure::source() const {
676 return _source;
677 }
679 inline void ParMarkBitMapClosure::set_source(HeapWord* addr) {
680 _source = addr;
681 }
683 inline void ParMarkBitMapClosure::decrement_words_remaining(size_t words) {
684 assert(_words_remaining >= words, "processed too many words");
685 _words_remaining -= words;
686 }
688 // The UseParallelOldGC collector is a stop-the-world garbage collector that
689 // does parts of the collection using parallel threads. The collection includes
690 // the tenured generation and the young generation. The permanent generation is
691 // collected at the same time as the other two generations but the permanent
692 // generation is collect by a single GC thread. The permanent generation is
693 // collected serially because of the requirement that during the processing of a
694 // klass AAA, any objects reference by AAA must already have been processed.
695 // This requirement is enforced by a left (lower address) to right (higher
696 // address) sliding compaction.
697 //
698 // There are four phases of the collection.
699 //
700 // - marking phase
701 // - summary phase
702 // - compacting phase
703 // - clean up phase
704 //
705 // Roughly speaking these phases correspond, respectively, to
706 // - mark all the live objects
707 // - calculate the destination of each object at the end of the collection
708 // - move the objects to their destination
709 // - update some references and reinitialize some variables
710 //
711 // These three phases are invoked in PSParallelCompact::invoke_no_policy(). The
712 // marking phase is implemented in PSParallelCompact::marking_phase() and does a
713 // complete marking of the heap. The summary phase is implemented in
714 // PSParallelCompact::summary_phase(). The move and update phase is implemented
715 // in PSParallelCompact::compact().
716 //
717 // A space that is being collected is divided into regions and with each region
718 // is associated an object of type ParallelCompactData. Each region is of a
719 // fixed size and typically will contain more than 1 object and may have parts
720 // of objects at the front and back of the region.
721 //
722 // region -----+---------------------+----------
723 // objects covered [ AAA )[ BBB )[ CCC )[ DDD )
724 //
725 // The marking phase does a complete marking of all live objects in the heap.
726 // The marking also compiles the size of the data for all live objects covered
727 // by the region. This size includes the part of any live object spanning onto
728 // the region (part of AAA if it is live) from the front, all live objects
729 // contained in the region (BBB and/or CCC if they are live), and the part of
730 // any live objects covered by the region that extends off the region (part of
731 // DDD if it is live). The marking phase uses multiple GC threads and marking
732 // is done in a bit array of type ParMarkBitMap. The marking of the bit map is
733 // done atomically as is the accumulation of the size of the live objects
734 // covered by a region.
735 //
736 // The summary phase calculates the total live data to the left of each region
737 // XXX. Based on that total and the bottom of the space, it can calculate the
738 // starting location of the live data in XXX. The summary phase calculates for
739 // each region XXX quantites such as
740 //
741 // - the amount of live data at the beginning of a region from an object
742 // entering the region.
743 // - the location of the first live data on the region
744 // - a count of the number of regions receiving live data from XXX.
745 //
746 // See ParallelCompactData for precise details. The summary phase also
747 // calculates the dense prefix for the compaction. The dense prefix is a
748 // portion at the beginning of the space that is not moved. The objects in the
749 // dense prefix do need to have their object references updated. See method
750 // summarize_dense_prefix().
751 //
752 // The summary phase is done using 1 GC thread.
753 //
754 // The compaction phase moves objects to their new location and updates all
755 // references in the object.
756 //
757 // A current exception is that objects that cross a region boundary are moved
758 // but do not have their references updated. References are not updated because
759 // it cannot easily be determined if the klass pointer KKK for the object AAA
760 // has been updated. KKK likely resides in a region to the left of the region
761 // containing AAA. These AAA's have there references updated at the end in a
762 // clean up phase. See the method PSParallelCompact::update_deferred_objects().
763 // An alternate strategy is being investigated for this deferral of updating.
764 //
765 // Compaction is done on a region basis. A region that is ready to be filled is
766 // put on a ready list and GC threads take region off the list and fill them. A
767 // region is ready to be filled if it empty of live objects. Such a region may
768 // have been initially empty (only contained dead objects) or may have had all
769 // its live objects copied out already. A region that compacts into itself is
770 // also ready for filling. The ready list is initially filled with empty
771 // regions and regions compacting into themselves. There is always at least 1
772 // region that can be put on the ready list. The regions are atomically added
773 // and removed from the ready list.
775 class PSParallelCompact : AllStatic {
776 public:
777 // Convenient access to type names.
778 typedef ParMarkBitMap::idx_t idx_t;
779 typedef ParallelCompactData::RegionData RegionData;
781 typedef enum {
782 perm_space_id, old_space_id, eden_space_id,
783 from_space_id, to_space_id, last_space_id
784 } SpaceId;
786 public:
787 // Inline closure decls
788 //
789 class IsAliveClosure: public BoolObjectClosure {
790 public:
791 virtual void do_object(oop p);
792 virtual bool do_object_b(oop p);
793 };
795 class KeepAliveClosure: public OopClosure {
796 private:
797 ParCompactionManager* _compaction_manager;
798 protected:
799 template <class T> inline void do_oop_work(T* p);
800 public:
801 KeepAliveClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }
802 virtual void do_oop(oop* p);
803 virtual void do_oop(narrowOop* p);
804 };
806 // Current unused
807 class FollowRootClosure: public OopsInGenClosure {
808 private:
809 ParCompactionManager* _compaction_manager;
810 public:
811 FollowRootClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }
812 virtual void do_oop(oop* p);
813 virtual void do_oop(narrowOop* p);
814 };
816 class FollowStackClosure: public VoidClosure {
817 private:
818 ParCompactionManager* _compaction_manager;
819 public:
820 FollowStackClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }
821 virtual void do_void();
822 };
824 class AdjustPointerClosure: public OopsInGenClosure {
825 private:
826 bool _is_root;
827 public:
828 AdjustPointerClosure(bool is_root) : _is_root(is_root) { }
829 virtual void do_oop(oop* p);
830 virtual void do_oop(narrowOop* p);
831 // do not walk from thread stacks to the code cache on this phase
832 virtual void do_code_blob(CodeBlob* cb) const { }
833 };
835 friend class KeepAliveClosure;
836 friend class FollowStackClosure;
837 friend class AdjustPointerClosure;
838 friend class FollowRootClosure;
839 friend class instanceKlassKlass;
840 friend class RefProcTaskProxy;
842 private:
843 static elapsedTimer _accumulated_time;
844 static unsigned int _total_invocations;
845 static unsigned int _maximum_compaction_gc_num;
846 static jlong _time_of_last_gc; // ms
847 static CollectorCounters* _counters;
848 static ParMarkBitMap _mark_bitmap;
849 static ParallelCompactData _summary_data;
850 static IsAliveClosure _is_alive_closure;
851 static SpaceInfo _space_info[last_space_id];
852 static bool _print_phases;
853 static AdjustPointerClosure _adjust_root_pointer_closure;
854 static AdjustPointerClosure _adjust_pointer_closure;
856 // Reference processing (used in ...follow_contents)
857 static ReferenceProcessor* _ref_processor;
859 // Updated location of intArrayKlassObj.
860 static klassOop _updated_int_array_klass_obj;
862 // Values computed at initialization and used by dead_wood_limiter().
863 static double _dwl_mean;
864 static double _dwl_std_dev;
865 static double _dwl_first_term;
866 static double _dwl_adjustment;
867 #ifdef ASSERT
868 static bool _dwl_initialized;
869 #endif // #ifdef ASSERT
871 private:
872 // Closure accessors
873 static OopClosure* adjust_pointer_closure() { return (OopClosure*)&_adjust_pointer_closure; }
874 static OopClosure* adjust_root_pointer_closure() { return (OopClosure*)&_adjust_root_pointer_closure; }
875 static BoolObjectClosure* is_alive_closure() { return (BoolObjectClosure*)&_is_alive_closure; }
877 static void initialize_space_info();
879 // Return true if details about individual phases should be printed.
880 static inline bool print_phases();
882 // Clear the marking bitmap and summary data that cover the specified space.
883 static void clear_data_covering_space(SpaceId id);
885 static void pre_compact(PreGCValues* pre_gc_values);
886 static void post_compact();
888 // Mark live objects
889 static void marking_phase(ParCompactionManager* cm,
890 bool maximum_heap_compaction);
891 static void follow_weak_klass_links();
892 static void follow_mdo_weak_refs();
894 template <class T> static inline void adjust_pointer(T* p, bool is_root);
895 static void adjust_root_pointer(oop* p) { adjust_pointer(p, true); }
897 template <class T>
898 static inline void follow_root(ParCompactionManager* cm, T* p);
900 // Compute the dense prefix for the designated space. This is an experimental
901 // implementation currently not used in production.
902 static HeapWord* compute_dense_prefix_via_density(const SpaceId id,
903 bool maximum_compaction);
905 // Methods used to compute the dense prefix.
907 // Compute the value of the normal distribution at x = density. The mean and
908 // standard deviation are values saved by initialize_dead_wood_limiter().
909 static inline double normal_distribution(double density);
911 // Initialize the static vars used by dead_wood_limiter().
912 static void initialize_dead_wood_limiter();
914 // Return the percentage of space that can be treated as "dead wood" (i.e.,
915 // not reclaimed).
916 static double dead_wood_limiter(double density, size_t min_percent);
918 // Find the first (left-most) region in the range [beg, end) that has at least
919 // dead_words of dead space to the left. The argument beg must be the first
920 // region in the space that is not completely live.
921 static RegionData* dead_wood_limit_region(const RegionData* beg,
922 const RegionData* end,
923 size_t dead_words);
925 // Return a pointer to the first region in the range [beg, end) that is not
926 // completely full.
927 static RegionData* first_dead_space_region(const RegionData* beg,
928 const RegionData* end);
930 // Return a value indicating the benefit or 'yield' if the compacted region
931 // were to start (or equivalently if the dense prefix were to end) at the
932 // candidate region. Higher values are better.
933 //
934 // The value is based on the amount of space reclaimed vs. the costs of (a)
935 // updating references in the dense prefix plus (b) copying objects and
936 // updating references in the compacted region.
937 static inline double reclaimed_ratio(const RegionData* const candidate,
938 HeapWord* const bottom,
939 HeapWord* const top,
940 HeapWord* const new_top);
942 // Compute the dense prefix for the designated space.
943 static HeapWord* compute_dense_prefix(const SpaceId id,
944 bool maximum_compaction);
946 // Return true if dead space crosses onto the specified Region; bit must be
947 // the bit index corresponding to the first word of the Region.
948 static inline bool dead_space_crosses_boundary(const RegionData* region,
949 idx_t bit);
951 // Summary phase utility routine to fill dead space (if any) at the dense
952 // prefix boundary. Should only be called if the the dense prefix is
953 // non-empty.
954 static void fill_dense_prefix_end(SpaceId id);
956 // Clear the summary data source_region field for the specified addresses.
957 static void clear_source_region(HeapWord* beg_addr, HeapWord* end_addr);
959 #ifndef PRODUCT
960 // Routines to provoke splitting a young gen space (ParallelOldGCSplitALot).
962 // Fill the region [start, start + words) with live object(s). Only usable
963 // for the old and permanent generations.
964 static void fill_with_live_objects(SpaceId id, HeapWord* const start,
965 size_t words);
966 // Include the new objects in the summary data.
967 static void summarize_new_objects(SpaceId id, HeapWord* start);
969 // Add live objects to a survivor space since it's rare that both survivors
970 // are non-empty.
971 static void provoke_split_fill_survivor(SpaceId id);
973 // Add live objects and/or choose the dense prefix to provoke splitting.
974 static void provoke_split(bool & maximum_compaction);
975 #endif
977 static void summarize_spaces_quick();
978 static void summarize_space(SpaceId id, bool maximum_compaction);
979 static void summary_phase(ParCompactionManager* cm, bool maximum_compaction);
981 // Adjust addresses in roots. Does not adjust addresses in heap.
982 static void adjust_roots();
984 // Serial code executed in preparation for the compaction phase.
985 static void compact_prologue();
987 // Move objects to new locations.
988 static void compact_perm(ParCompactionManager* cm);
989 static void compact();
991 // Add available regions to the stack and draining tasks to the task queue.
992 static void enqueue_region_draining_tasks(GCTaskQueue* q,
993 uint parallel_gc_threads);
995 // Add dense prefix update tasks to the task queue.
996 static void enqueue_dense_prefix_tasks(GCTaskQueue* q,
997 uint parallel_gc_threads);
999 // Add region stealing tasks to the task queue.
1000 static void enqueue_region_stealing_tasks(
1001 GCTaskQueue* q,
1002 ParallelTaskTerminator* terminator_ptr,
1003 uint parallel_gc_threads);
1005 // If objects are left in eden after a collection, try to move the boundary
1006 // and absorb them into the old gen. Returns true if eden was emptied.
1007 static bool absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
1008 PSYoungGen* young_gen,
1009 PSOldGen* old_gen);
1011 // Reset time since last full gc
1012 static void reset_millis_since_last_gc();
1014 protected:
1015 #ifdef VALIDATE_MARK_SWEEP
1016 static GrowableArray<void*>* _root_refs_stack;
1017 static GrowableArray<oop> * _live_oops;
1018 static GrowableArray<oop> * _live_oops_moved_to;
1019 static GrowableArray<size_t>* _live_oops_size;
1020 static size_t _live_oops_index;
1021 static size_t _live_oops_index_at_perm;
1022 static GrowableArray<void*>* _other_refs_stack;
1023 static GrowableArray<void*>* _adjusted_pointers;
1024 static bool _pointer_tracking;
1025 static bool _root_tracking;
1027 // The following arrays are saved since the time of the last GC and
1028 // assist in tracking down problems where someone has done an errant
1029 // store into the heap, usually to an oop that wasn't properly
1030 // handleized across a GC. If we crash or otherwise fail before the
1031 // next GC, we can query these arrays to find out the object we had
1032 // intended to do the store to (assuming it is still alive) and the
1033 // offset within that object. Covered under RecordMarkSweepCompaction.
1034 static GrowableArray<HeapWord*> * _cur_gc_live_oops;
1035 static GrowableArray<HeapWord*> * _cur_gc_live_oops_moved_to;
1036 static GrowableArray<size_t>* _cur_gc_live_oops_size;
1037 static GrowableArray<HeapWord*> * _last_gc_live_oops;
1038 static GrowableArray<HeapWord*> * _last_gc_live_oops_moved_to;
1039 static GrowableArray<size_t>* _last_gc_live_oops_size;
1040 #endif
1042 public:
1043 class MarkAndPushClosure: public OopClosure {
1044 private:
1045 ParCompactionManager* _compaction_manager;
1046 public:
1047 MarkAndPushClosure(ParCompactionManager* cm) : _compaction_manager(cm) { }
1048 virtual void do_oop(oop* p);
1049 virtual void do_oop(narrowOop* p);
1050 };
1052 PSParallelCompact();
1054 // Convenient accessor for Universe::heap().
1055 static ParallelScavengeHeap* gc_heap() {
1056 return (ParallelScavengeHeap*)Universe::heap();
1057 }
1059 static void invoke(bool maximum_heap_compaction);
1060 static bool invoke_no_policy(bool maximum_heap_compaction);
1062 static void post_initialize();
1063 // Perform initialization for PSParallelCompact that requires
1064 // allocations. This should be called during the VM initialization
1065 // at a pointer where it would be appropriate to return a JNI_ENOMEM
1066 // in the event of a failure.
1067 static bool initialize();
1069 // Public accessors
1070 static elapsedTimer* accumulated_time() { return &_accumulated_time; }
1071 static unsigned int total_invocations() { return _total_invocations; }
1072 static CollectorCounters* counters() { return _counters; }
1074 // Used to add tasks
1075 static GCTaskManager* const gc_task_manager();
1076 static klassOop updated_int_array_klass_obj() {
1077 return _updated_int_array_klass_obj;
1078 }
1080 // Marking support
1081 static inline bool mark_obj(oop obj);
1082 // Check mark and maybe push on marking stack
1083 template <class T> static inline void mark_and_push(ParCompactionManager* cm,
1084 T* p);
1086 // Compaction support.
1087 // Return true if p is in the range [beg_addr, end_addr).
1088 static inline bool is_in(HeapWord* p, HeapWord* beg_addr, HeapWord* end_addr);
1089 static inline bool is_in(oop* p, HeapWord* beg_addr, HeapWord* end_addr);
1091 // Convenience wrappers for per-space data kept in _space_info.
1092 static inline MutableSpace* space(SpaceId space_id);
1093 static inline HeapWord* new_top(SpaceId space_id);
1094 static inline HeapWord* dense_prefix(SpaceId space_id);
1095 static inline ObjectStartArray* start_array(SpaceId space_id);
1097 // Return true if the klass should be updated.
1098 static inline bool should_update_klass(klassOop k);
1100 // Move and update the live objects in the specified space.
1101 static void move_and_update(ParCompactionManager* cm, SpaceId space_id);
1103 // Process the end of the given region range in the dense prefix.
1104 // This includes saving any object not updated.
1105 static void dense_prefix_regions_epilogue(ParCompactionManager* cm,
1106 size_t region_start_index,
1107 size_t region_end_index,
1108 idx_t exiting_object_offset,
1109 idx_t region_offset_start,
1110 idx_t region_offset_end);
1112 // Update a region in the dense prefix. For each live object
1113 // in the region, update it's interior references. For each
1114 // dead object, fill it with deadwood. Dead space at the end
1115 // of a region range will be filled to the start of the next
1116 // live object regardless of the region_index_end. None of the
1117 // objects in the dense prefix move and dead space is dead
1118 // (holds only dead objects that don't need any processing), so
1119 // dead space can be filled in any order.
1120 static void update_and_deadwood_in_dense_prefix(ParCompactionManager* cm,
1121 SpaceId space_id,
1122 size_t region_index_start,
1123 size_t region_index_end);
1125 // Return the address of the count + 1st live word in the range [beg, end).
1126 static HeapWord* skip_live_words(HeapWord* beg, HeapWord* end, size_t count);
1128 // Return the address of the word to be copied to dest_addr, which must be
1129 // aligned to a region boundary.
1130 static HeapWord* first_src_addr(HeapWord* const dest_addr,
1131 SpaceId src_space_id,
1132 size_t src_region_idx);
1134 // Determine the next source region, set closure.source() to the start of the
1135 // new region return the region index. Parameter end_addr is the address one
1136 // beyond the end of source range just processed. If necessary, switch to a
1137 // new source space and set src_space_id (in-out parameter) and src_space_top
1138 // (out parameter) accordingly.
1139 static size_t next_src_region(MoveAndUpdateClosure& closure,
1140 SpaceId& src_space_id,
1141 HeapWord*& src_space_top,
1142 HeapWord* end_addr);
1144 // Decrement the destination count for each non-empty source region in the
1145 // range [beg_region, region(region_align_up(end_addr))). If the destination
1146 // count for a region goes to 0 and it needs to be filled, enqueue it.
1147 static void decrement_destination_counts(ParCompactionManager* cm,
1148 SpaceId src_space_id,
1149 size_t beg_region,
1150 HeapWord* end_addr);
1152 // Fill a region, copying objects from one or more source regions.
1153 static void fill_region(ParCompactionManager* cm, size_t region_idx);
1154 static void fill_and_update_region(ParCompactionManager* cm, size_t region) {
1155 fill_region(cm, region);
1156 }
1158 // Update the deferred objects in the space.
1159 static void update_deferred_objects(ParCompactionManager* cm, SpaceId id);
1161 static ParMarkBitMap* mark_bitmap() { return &_mark_bitmap; }
1162 static ParallelCompactData& summary_data() { return _summary_data; }
1164 static inline void adjust_pointer(oop* p) { adjust_pointer(p, false); }
1165 static inline void adjust_pointer(narrowOop* p) { adjust_pointer(p, false); }
1167 // Reference Processing
1168 static ReferenceProcessor* const ref_processor() { return _ref_processor; }
1170 // Return the SpaceId for the given address.
1171 static SpaceId space_id(HeapWord* addr);
1173 // Time since last full gc (in milliseconds).
1174 static jlong millis_since_last_gc();
1176 #ifdef VALIDATE_MARK_SWEEP
1177 static void track_adjusted_pointer(void* p, bool isroot);
1178 static void check_adjust_pointer(void* p);
1179 static void track_interior_pointers(oop obj);
1180 static void check_interior_pointers();
1182 static void reset_live_oop_tracking(bool at_perm);
1183 static void register_live_oop(oop p, size_t size);
1184 static void validate_live_oop(oop p, size_t size);
1185 static void live_oop_moved_to(HeapWord* q, size_t size, HeapWord* compaction_top);
1186 static void compaction_complete();
1188 // Querying operation of RecordMarkSweepCompaction results.
1189 // Finds and prints the current base oop and offset for a word
1190 // within an oop that was live during the last GC. Helpful for
1191 // tracking down heap stomps.
1192 static void print_new_location_of_heap_address(HeapWord* q);
1193 #endif // #ifdef VALIDATE_MARK_SWEEP
1195 // Call backs for class unloading
1196 // Update subklass/sibling/implementor links at end of marking.
1197 static void revisit_weak_klass_link(ParCompactionManager* cm, Klass* k);
1199 // Clear unmarked oops in MDOs at the end of marking.
1200 static void revisit_mdo(ParCompactionManager* cm, DataLayout* p);
1202 #ifndef PRODUCT
1203 // Debugging support.
1204 static const char* space_names[last_space_id];
1205 static void print_region_ranges();
1206 static void print_dense_prefix_stats(const char* const algorithm,
1207 const SpaceId id,
1208 const bool maximum_compaction,
1209 HeapWord* const addr);
1210 static void summary_phase_msg(SpaceId dst_space_id,
1211 HeapWord* dst_beg, HeapWord* dst_end,
1212 SpaceId src_space_id,
1213 HeapWord* src_beg, HeapWord* src_end);
1214 #endif // #ifndef PRODUCT
1216 #ifdef ASSERT
1217 // Sanity check the new location of a word in the heap.
1218 static inline void check_new_location(HeapWord* old_addr, HeapWord* new_addr);
1219 // Verify that all the regions have been emptied.
1220 static void verify_complete(SpaceId space_id);
1221 #endif // #ifdef ASSERT
1222 };
1224 inline bool PSParallelCompact::mark_obj(oop obj) {
1225 const int obj_size = obj->size();
1226 if (mark_bitmap()->mark_obj(obj, obj_size)) {
1227 _summary_data.add_obj(obj, obj_size);
1228 return true;
1229 } else {
1230 return false;
1231 }
1232 }
1234 template <class T>
1235 inline void PSParallelCompact::follow_root(ParCompactionManager* cm, T* p) {
1236 assert(!Universe::heap()->is_in_reserved(p),
1237 "roots shouldn't be things within the heap");
1238 #ifdef VALIDATE_MARK_SWEEP
1239 if (ValidateMarkSweep) {
1240 guarantee(!_root_refs_stack->contains(p), "should only be in here once");
1241 _root_refs_stack->push(p);
1242 }
1243 #endif
1244 T heap_oop = oopDesc::load_heap_oop(p);
1245 if (!oopDesc::is_null(heap_oop)) {
1246 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
1247 if (mark_bitmap()->is_unmarked(obj)) {
1248 if (mark_obj(obj)) {
1249 obj->follow_contents(cm);
1250 }
1251 }
1252 }
1253 cm->follow_marking_stacks();
1254 }
1256 template <class T>
1257 inline void PSParallelCompact::mark_and_push(ParCompactionManager* cm, T* p) {
1258 T heap_oop = oopDesc::load_heap_oop(p);
1259 if (!oopDesc::is_null(heap_oop)) {
1260 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
1261 if (mark_bitmap()->is_unmarked(obj) && mark_obj(obj)) {
1262 cm->push(obj);
1263 }
1264 }
1265 }
1267 template <class T>
1268 inline void PSParallelCompact::adjust_pointer(T* p, bool isroot) {
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 oop new_obj = (oop)summary_data().calc_new_pointer(obj);
1273 assert(new_obj != NULL || // is forwarding ptr?
1274 obj->is_shared(), // never forwarded?
1275 "should be forwarded");
1276 // Just always do the update unconditionally?
1277 if (new_obj != NULL) {
1278 assert(Universe::heap()->is_in_reserved(new_obj),
1279 "should be in object space");
1280 oopDesc::encode_store_heap_oop_not_null(p, new_obj);
1281 }
1282 }
1283 VALIDATE_MARK_SWEEP_ONLY(track_adjusted_pointer(p, isroot));
1284 }
1286 template <class T>
1287 inline void PSParallelCompact::KeepAliveClosure::do_oop_work(T* p) {
1288 #ifdef VALIDATE_MARK_SWEEP
1289 if (ValidateMarkSweep) {
1290 if (!Universe::heap()->is_in_reserved(p)) {
1291 _root_refs_stack->push(p);
1292 } else {
1293 _other_refs_stack->push(p);
1294 }
1295 }
1296 #endif
1297 mark_and_push(_compaction_manager, p);
1298 }
1300 inline bool PSParallelCompact::print_phases() {
1301 return _print_phases;
1302 }
1304 inline double PSParallelCompact::normal_distribution(double density) {
1305 assert(_dwl_initialized, "uninitialized");
1306 const double squared_term = (density - _dwl_mean) / _dwl_std_dev;
1307 return _dwl_first_term * exp(-0.5 * squared_term * squared_term);
1308 }
1310 inline bool
1311 PSParallelCompact::dead_space_crosses_boundary(const RegionData* region,
1312 idx_t bit)
1313 {
1314 assert(bit > 0, "cannot call this for the first bit/region");
1315 assert(_summary_data.region_to_addr(region) == _mark_bitmap.bit_to_addr(bit),
1316 "sanity check");
1318 // Dead space crosses the boundary if (1) a partial object does not extend
1319 // onto the region, (2) an object does not start at the beginning of the
1320 // region, and (3) an object does not end at the end of the prior region.
1321 return region->partial_obj_size() == 0 &&
1322 !_mark_bitmap.is_obj_beg(bit) &&
1323 !_mark_bitmap.is_obj_end(bit - 1);
1324 }
1326 inline bool
1327 PSParallelCompact::is_in(HeapWord* p, HeapWord* beg_addr, HeapWord* end_addr) {
1328 return p >= beg_addr && p < end_addr;
1329 }
1331 inline bool
1332 PSParallelCompact::is_in(oop* p, HeapWord* beg_addr, HeapWord* end_addr) {
1333 return is_in((HeapWord*)p, beg_addr, end_addr);
1334 }
1336 inline MutableSpace* PSParallelCompact::space(SpaceId id) {
1337 assert(id < last_space_id, "id out of range");
1338 return _space_info[id].space();
1339 }
1341 inline HeapWord* PSParallelCompact::new_top(SpaceId id) {
1342 assert(id < last_space_id, "id out of range");
1343 return _space_info[id].new_top();
1344 }
1346 inline HeapWord* PSParallelCompact::dense_prefix(SpaceId id) {
1347 assert(id < last_space_id, "id out of range");
1348 return _space_info[id].dense_prefix();
1349 }
1351 inline ObjectStartArray* PSParallelCompact::start_array(SpaceId id) {
1352 assert(id < last_space_id, "id out of range");
1353 return _space_info[id].start_array();
1354 }
1356 inline bool PSParallelCompact::should_update_klass(klassOop k) {
1357 return ((HeapWord*) k) >= dense_prefix(perm_space_id);
1358 }
1360 #ifdef ASSERT
1361 inline void
1362 PSParallelCompact::check_new_location(HeapWord* old_addr, HeapWord* new_addr)
1363 {
1364 assert(old_addr >= new_addr || space_id(old_addr) != space_id(new_addr),
1365 "must move left or to a different space");
1366 assert(is_object_aligned((intptr_t)old_addr) && is_object_aligned((intptr_t)new_addr),
1367 "checking alignment");
1368 }
1369 #endif // ASSERT
1371 class MoveAndUpdateClosure: public ParMarkBitMapClosure {
1372 public:
1373 inline MoveAndUpdateClosure(ParMarkBitMap* bitmap, ParCompactionManager* cm,
1374 ObjectStartArray* start_array,
1375 HeapWord* destination, size_t words);
1377 // Accessors.
1378 HeapWord* destination() const { return _destination; }
1380 // If the object will fit (size <= words_remaining()), copy it to the current
1381 // destination, update the interior oops and the start array and return either
1382 // full (if the closure is full) or incomplete. If the object will not fit,
1383 // return would_overflow.
1384 virtual IterationStatus do_addr(HeapWord* addr, size_t size);
1386 // Copy enough words to fill this closure, starting at source(). Interior
1387 // oops and the start array are not updated. Return full.
1388 IterationStatus copy_until_full();
1390 // Copy enough words to fill this closure or to the end of an object,
1391 // whichever is smaller, starting at source(). Interior oops and the start
1392 // array are not updated.
1393 void copy_partial_obj();
1395 protected:
1396 // Update variables to indicate that word_count words were processed.
1397 inline void update_state(size_t word_count);
1399 protected:
1400 ObjectStartArray* const _start_array;
1401 HeapWord* _destination; // Next addr to be written.
1402 };
1404 inline
1405 MoveAndUpdateClosure::MoveAndUpdateClosure(ParMarkBitMap* bitmap,
1406 ParCompactionManager* cm,
1407 ObjectStartArray* start_array,
1408 HeapWord* destination,
1409 size_t words) :
1410 ParMarkBitMapClosure(bitmap, cm, words), _start_array(start_array)
1411 {
1412 _destination = destination;
1413 }
1415 inline void MoveAndUpdateClosure::update_state(size_t words)
1416 {
1417 decrement_words_remaining(words);
1418 _source += words;
1419 _destination += words;
1420 }
1422 class UpdateOnlyClosure: public ParMarkBitMapClosure {
1423 private:
1424 const PSParallelCompact::SpaceId _space_id;
1425 ObjectStartArray* const _start_array;
1427 public:
1428 UpdateOnlyClosure(ParMarkBitMap* mbm,
1429 ParCompactionManager* cm,
1430 PSParallelCompact::SpaceId space_id);
1432 // Update the object.
1433 virtual IterationStatus do_addr(HeapWord* addr, size_t words);
1435 inline void do_addr(HeapWord* addr);
1436 };
1438 inline void UpdateOnlyClosure::do_addr(HeapWord* addr)
1439 {
1440 _start_array->allocate_block(addr);
1441 oop(addr)->update_contents(compaction_manager());
1442 }
1444 class FillClosure: public ParMarkBitMapClosure
1445 {
1446 public:
1447 FillClosure(ParCompactionManager* cm, PSParallelCompact::SpaceId space_id) :
1448 ParMarkBitMapClosure(PSParallelCompact::mark_bitmap(), cm),
1449 _start_array(PSParallelCompact::start_array(space_id))
1450 {
1451 assert(space_id == PSParallelCompact::perm_space_id ||
1452 space_id == PSParallelCompact::old_space_id,
1453 "cannot use FillClosure in the young gen");
1454 }
1456 virtual IterationStatus do_addr(HeapWord* addr, size_t size) {
1457 CollectedHeap::fill_with_objects(addr, size);
1458 HeapWord* const end = addr + size;
1459 do {
1460 _start_array->allocate_block(addr);
1461 addr += oop(addr)->size();
1462 } while (addr < end);
1463 return ParMarkBitMap::incomplete;
1464 }
1466 private:
1467 ObjectStartArray* const _start_array;
1468 };
1470 #endif // SHARE_VM_GC_IMPLEMENTATION_PARALLELSCAVENGE_PSPARALLELCOMPACT_HPP