1 /*
2 * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "gc_implementation/shared/spaceDecorator.hpp"
27 #include "gc_interface/collectedHeap.inline.hpp"
28 #include "memory/allocation.inline.hpp"
29 #include "memory/blockOffsetTable.inline.hpp"
30 #include "memory/cardTableRS.hpp"
31 #include "memory/gcLocker.inline.hpp"
32 #include "memory/genCollectedHeap.hpp"
33 #include "memory/genMarkSweep.hpp"
34 #include "memory/genOopClosures.hpp"
35 #include "memory/genOopClosures.inline.hpp"
36 #include "memory/generation.hpp"
37 #include "memory/generation.inline.hpp"
38 #include "memory/space.inline.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "runtime/java.hpp"
41 #include "utilities/copy.hpp"
42 #include "utilities/events.hpp"
43
44 Generation::Generation(ReservedSpace rs, size_t initial_size, int level) :
45 _level(level),
46 _ref_processor(NULL) {
47 if (!_virtual_space.initialize(rs, initial_size)) {
48 vm_exit_during_initialization("Could not reserve enough space for "
49 "object heap");
50 }
51 // Mangle all of the the initial generation.
52 if (ZapUnusedHeapArea) {
53 MemRegion mangle_region((HeapWord*)_virtual_space.low(),
54 (HeapWord*)_virtual_space.high());
55 SpaceMangler::mangle_region(mangle_region);
56 }
57 _reserved = MemRegion((HeapWord*)_virtual_space.low_boundary(),
58 (HeapWord*)_virtual_space.high_boundary());
59 }
60
61 GenerationSpec* Generation::spec() {
62 GenCollectedHeap* gch = GenCollectedHeap::heap();
63 assert(0 <= level() && level() < gch->_n_gens, "Bad gen level");
64 return gch->_gen_specs[level()];
65 }
66
67 size_t Generation::max_capacity() const {
68 return reserved().byte_size();
69 }
70
71 void Generation::print_heap_change(size_t prev_used) const {
72 if (PrintGCDetails && Verbose) {
73 gclog_or_tty->print(" " SIZE_FORMAT
74 "->" SIZE_FORMAT
75 "(" SIZE_FORMAT ")",
76 prev_used, used(), capacity());
77 } else {
78 gclog_or_tty->print(" " SIZE_FORMAT "K"
79 "->" SIZE_FORMAT "K"
80 "(" SIZE_FORMAT "K)",
81 prev_used / K, used() / K, capacity() / K);
82 }
83 }
84
85 // By default we get a single threaded default reference processor;
86 // generations needing multi-threaded refs processing or discovery override this method.
87 void Generation::ref_processor_init() {
88 assert(_ref_processor == NULL, "a reference processor already exists");
89 assert(!_reserved.is_empty(), "empty generation?");
90 _ref_processor = new ReferenceProcessor(_reserved); // a vanilla reference processor
91 if (_ref_processor == NULL) {
92 vm_exit_during_initialization("Could not allocate ReferenceProcessor object");
93 }
94 }
95
96 void Generation::print() const { print_on(tty); }
97
98 void Generation::print_on(outputStream* st) const {
99 st->print(" %-20s", name());
100 st->print(" total " SIZE_FORMAT "K, used " SIZE_FORMAT "K",
101 capacity()/K, used()/K);
102 st->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", " INTPTR_FORMAT ")",
103 _virtual_space.low_boundary(),
104 _virtual_space.high(),
105 _virtual_space.high_boundary());
106 }
107
108 void Generation::print_summary_info() { print_summary_info_on(tty); }
109
110 void Generation::print_summary_info_on(outputStream* st) {
111 StatRecord* sr = stat_record();
112 double time = sr->accumulated_time.seconds();
113 st->print_cr("[Accumulated GC generation %d time %3.7f secs, "
114 "%d GC's, avg GC time %3.7f]",
115 level(), time, sr->invocations,
116 sr->invocations > 0 ? time / sr->invocations : 0.0);
117 }
118
119 // Utility iterator classes
120
121 class GenerationIsInReservedClosure : public SpaceClosure {
122 public:
123 const void* _p;
124 Space* sp;
125 virtual void do_space(Space* s) {
126 if (sp == NULL) {
127 if (s->is_in_reserved(_p)) sp = s;
128 }
129 }
130 GenerationIsInReservedClosure(const void* p) : _p(p), sp(NULL) {}
131 };
132
133 class GenerationIsInClosure : public SpaceClosure {
134 public:
135 const void* _p;
136 Space* sp;
137 virtual void do_space(Space* s) {
138 if (sp == NULL) {
139 if (s->is_in(_p)) sp = s;
140 }
141 }
142 GenerationIsInClosure(const void* p) : _p(p), sp(NULL) {}
143 };
144
145 bool Generation::is_in(const void* p) const {
146 GenerationIsInClosure blk(p);
147 ((Generation*)this)->space_iterate(&blk);
148 return blk.sp != NULL;
149 }
150
151 DefNewGeneration* Generation::as_DefNewGeneration() {
152 assert((kind() == Generation::DefNew) ||
153 (kind() == Generation::ParNew) ||
154 (kind() == Generation::ASParNew),
155 "Wrong youngest generation type");
156 return (DefNewGeneration*) this;
157 }
158
159 Generation* Generation::next_gen() const {
160 GenCollectedHeap* gch = GenCollectedHeap::heap();
161 int next = level() + 1;
162 if (next < gch->_n_gens) {
163 return gch->_gens[next];
164 } else {
165 return NULL;
166 }
167 }
168
169 size_t Generation::max_contiguous_available() const {
170 // The largest number of contiguous free words in this or any higher generation.
171 size_t max = 0;
172 for (const Generation* gen = this; gen != NULL; gen = gen->next_gen()) {
173 size_t avail = gen->contiguous_available();
174 if (avail > max) {
175 max = avail;
176 }
177 }
178 return max;
179 }
180
181 bool Generation::promotion_attempt_is_safe(size_t max_promotion_in_bytes) const {
182 size_t available = max_contiguous_available();
183 bool res = (available >= max_promotion_in_bytes);
184 if (PrintGC && Verbose) {
185 gclog_or_tty->print_cr(
186 "Generation: promo attempt is%s safe: available("SIZE_FORMAT") %s max_promo("SIZE_FORMAT")",
187 res? "":" not", available, res? ">=":"<",
188 max_promotion_in_bytes);
189 }
190 return res;
191 }
192
193 // Ignores "ref" and calls allocate().
194 oop Generation::promote(oop obj, size_t obj_size) {
195 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
196
197 #ifndef PRODUCT
198 if (Universe::heap()->promotion_should_fail()) {
199 return NULL;
200 }
201 #endif // #ifndef PRODUCT
202
203 HeapWord* result = allocate(obj_size, false);
204 if (result != NULL) {
205 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
206 return oop(result);
207 } else {
208 GenCollectedHeap* gch = GenCollectedHeap::heap();
209 return gch->handle_failed_promotion(this, obj, obj_size);
210 }
211 }
212
213 oop Generation::par_promote(int thread_num,
214 oop obj, markOop m, size_t word_sz) {
215 // Could do a bad general impl here that gets a lock. But no.
216 ShouldNotCallThis();
217 return NULL;
218 }
219
220 void Generation::par_promote_alloc_undo(int thread_num,
221 HeapWord* obj, size_t word_sz) {
222 // Could do a bad general impl here that gets a lock. But no.
223 guarantee(false, "No good general implementation.");
224 }
225
226 Space* Generation::space_containing(const void* p) const {
227 GenerationIsInReservedClosure blk(p);
228 // Cast away const
229 ((Generation*)this)->space_iterate(&blk);
230 return blk.sp;
231 }
232
233 // Some of these are mediocre general implementations. Should be
234 // overridden to get better performance.
235
236 class GenerationBlockStartClosure : public SpaceClosure {
237 public:
238 const void* _p;
239 HeapWord* _start;
240 virtual void do_space(Space* s) {
241 if (_start == NULL && s->is_in_reserved(_p)) {
242 _start = s->block_start(_p);
243 }
244 }
245 GenerationBlockStartClosure(const void* p) { _p = p; _start = NULL; }
246 };
247
248 HeapWord* Generation::block_start(const void* p) const {
249 GenerationBlockStartClosure blk(p);
250 // Cast away const
251 ((Generation*)this)->space_iterate(&blk);
252 return blk._start;
253 }
254
255 class GenerationBlockSizeClosure : public SpaceClosure {
256 public:
257 const HeapWord* _p;
258 size_t size;
259 virtual void do_space(Space* s) {
260 if (size == 0 && s->is_in_reserved(_p)) {
261 size = s->block_size(_p);
262 }
263 }
264 GenerationBlockSizeClosure(const HeapWord* p) { _p = p; size = 0; }
265 };
266
267 size_t Generation::block_size(const HeapWord* p) const {
268 GenerationBlockSizeClosure blk(p);
269 // Cast away const
270 ((Generation*)this)->space_iterate(&blk);
271 assert(blk.size > 0, "seems reasonable");
272 return blk.size;
273 }
274
275 class GenerationBlockIsObjClosure : public SpaceClosure {
276 public:
277 const HeapWord* _p;
278 bool is_obj;
279 virtual void do_space(Space* s) {
280 if (!is_obj && s->is_in_reserved(_p)) {
281 is_obj |= s->block_is_obj(_p);
282 }
283 }
284 GenerationBlockIsObjClosure(const HeapWord* p) { _p = p; is_obj = false; }
285 };
286
287 bool Generation::block_is_obj(const HeapWord* p) const {
288 GenerationBlockIsObjClosure blk(p);
289 // Cast away const
290 ((Generation*)this)->space_iterate(&blk);
291 return blk.is_obj;
292 }
293
294 class GenerationOopIterateClosure : public SpaceClosure {
295 public:
296 ExtendedOopClosure* cl;
297 MemRegion mr;
298 virtual void do_space(Space* s) {
299 s->oop_iterate(mr, cl);
300 }
301 GenerationOopIterateClosure(ExtendedOopClosure* _cl, MemRegion _mr) :
302 cl(_cl), mr(_mr) {}
303 };
304
305 void Generation::oop_iterate(ExtendedOopClosure* cl) {
306 GenerationOopIterateClosure blk(cl, _reserved);
307 space_iterate(&blk);
308 }
309
310 void Generation::oop_iterate(MemRegion mr, ExtendedOopClosure* cl) {
311 GenerationOopIterateClosure blk(cl, mr);
312 space_iterate(&blk);
313 }
314
315 void Generation::younger_refs_in_space_iterate(Space* sp,
316 OopsInGenClosure* cl) {
317 GenRemSet* rs = SharedHeap::heap()->rem_set();
318 rs->younger_refs_in_space_iterate(sp, cl);
319 }
320
321 class GenerationObjIterateClosure : public SpaceClosure {
322 private:
323 ObjectClosure* _cl;
324 public:
325 virtual void do_space(Space* s) {
326 s->object_iterate(_cl);
327 }
328 GenerationObjIterateClosure(ObjectClosure* cl) : _cl(cl) {}
329 };
330
331 void Generation::object_iterate(ObjectClosure* cl) {
332 GenerationObjIterateClosure blk(cl);
333 space_iterate(&blk);
334 }
335
336 class GenerationSafeObjIterateClosure : public SpaceClosure {
337 private:
338 ObjectClosure* _cl;
339 public:
340 virtual void do_space(Space* s) {
341 s->safe_object_iterate(_cl);
342 }
343 GenerationSafeObjIterateClosure(ObjectClosure* cl) : _cl(cl) {}
344 };
345
346 void Generation::safe_object_iterate(ObjectClosure* cl) {
347 GenerationSafeObjIterateClosure blk(cl);
348 space_iterate(&blk);
349 }
350
351 void Generation::prepare_for_compaction(CompactPoint* cp) {
352 // Generic implementation, can be specialized
353 CompactibleSpace* space = first_compaction_space();
354 while (space != NULL) {
355 space->prepare_for_compaction(cp);
356 space = space->next_compaction_space();
357 }
358 }
359
360 class AdjustPointersClosure: public SpaceClosure {
361 public:
362 void do_space(Space* sp) {
363 sp->adjust_pointers();
364 }
365 };
366
367 void Generation::adjust_pointers() {
368 // Note that this is done over all spaces, not just the compactible
369 // ones.
370 AdjustPointersClosure blk;
371 space_iterate(&blk, true);
372 }
373
374 void Generation::compact() {
375 CompactibleSpace* sp = first_compaction_space();
376 while (sp != NULL) {
377 sp->compact();
378 sp = sp->next_compaction_space();
379 }
380 }
381
382 CardGeneration::CardGeneration(ReservedSpace rs, size_t initial_byte_size,
383 int level,
384 GenRemSet* remset) :
385 Generation(rs, initial_byte_size, level), _rs(remset),
386 _shrink_factor(0), _min_heap_delta_bytes(), _capacity_at_prologue(),
387 _used_at_prologue()
388 {
389 HeapWord* start = (HeapWord*)rs.base();
390 size_t reserved_byte_size = rs.size();
391 assert((uintptr_t(start) & 3) == 0, "bad alignment");
392 assert((reserved_byte_size & 3) == 0, "bad alignment");
393 MemRegion reserved_mr(start, heap_word_size(reserved_byte_size));
394 _bts = new BlockOffsetSharedArray(reserved_mr,
395 heap_word_size(initial_byte_size));
396 MemRegion committed_mr(start, heap_word_size(initial_byte_size));
397 _rs->resize_covered_region(committed_mr);
398 if (_bts == NULL)
399 vm_exit_during_initialization("Could not allocate a BlockOffsetArray");
400
401 // Verify that the start and end of this generation is the start of a card.
402 // If this wasn't true, a single card could span more than on generation,
403 // which would cause problems when we commit/uncommit memory, and when we
404 // clear and dirty cards.
405 guarantee(_rs->is_aligned(reserved_mr.start()), "generation must be card aligned");
406 if (reserved_mr.end() != Universe::heap()->reserved_region().end()) {
407 // Don't check at the very end of the heap as we'll assert that we're probing off
408 // the end if we try.
409 guarantee(_rs->is_aligned(reserved_mr.end()), "generation must be card aligned");
410 }
411 _min_heap_delta_bytes = MinHeapDeltaBytes;
412 _capacity_at_prologue = initial_byte_size;
413 _used_at_prologue = 0;
414 }
415
416 bool CardGeneration::expand(size_t bytes, size_t expand_bytes) {
417 assert_locked_or_safepoint(Heap_lock);
418 if (bytes == 0) {
419 return true; // That's what grow_by(0) would return
420 }
421 size_t aligned_bytes = ReservedSpace::page_align_size_up(bytes);
422 if (aligned_bytes == 0){
423 // The alignment caused the number of bytes to wrap. An expand_by(0) will
424 // return true with the implication that an expansion was done when it
425 // was not. A call to expand implies a best effort to expand by "bytes"
426 // but not a guarantee. Align down to give a best effort. This is likely
427 // the most that the generation can expand since it has some capacity to
428 // start with.
429 aligned_bytes = ReservedSpace::page_align_size_down(bytes);
430 }
431 size_t aligned_expand_bytes = ReservedSpace::page_align_size_up(expand_bytes);
432 bool success = false;
433 if (aligned_expand_bytes > aligned_bytes) {
434 success = grow_by(aligned_expand_bytes);
435 }
436 if (!success) {
437 success = grow_by(aligned_bytes);
438 }
439 if (!success) {
440 success = grow_to_reserved();
441 }
442 if (PrintGC && Verbose) {
443 if (success && GC_locker::is_active_and_needs_gc()) {
444 gclog_or_tty->print_cr("Garbage collection disabled, expanded heap instead");
445 }
446 }
447
448 return success;
449 }
450
451
452 // No young generation references, clear this generation's cards.
453 void CardGeneration::clear_remembered_set() {
454 _rs->clear(reserved());
455 }
456
457
458 // Objects in this generation may have moved, invalidate this
459 // generation's cards.
460 void CardGeneration::invalidate_remembered_set() {
461 _rs->invalidate(used_region());
462 }
463
464
465 void CardGeneration::compute_new_size() {
466 assert(_shrink_factor <= 100, "invalid shrink factor");
467 size_t current_shrink_factor = _shrink_factor;
468 _shrink_factor = 0;
469
470 // We don't have floating point command-line arguments
471 // Note: argument processing ensures that MinHeapFreeRatio < 100.
472 const double minimum_free_percentage = MinHeapFreeRatio / 100.0;
473 const double maximum_used_percentage = 1.0 - minimum_free_percentage;
474
475 // Compute some numbers about the state of the heap.
476 const size_t used_after_gc = used();
477 const size_t capacity_after_gc = capacity();
478
479 const double min_tmp = used_after_gc / maximum_used_percentage;
480 size_t minimum_desired_capacity = (size_t)MIN2(min_tmp, double(max_uintx));
481 // Don't shrink less than the initial generation size
482 minimum_desired_capacity = MAX2(minimum_desired_capacity,
483 spec()->init_size());
484 assert(used_after_gc <= minimum_desired_capacity, "sanity check");
485
486 if (PrintGC && Verbose) {
487 const size_t free_after_gc = free();
488 const double free_percentage = ((double)free_after_gc) / capacity_after_gc;
489 gclog_or_tty->print_cr("TenuredGeneration::compute_new_size: ");
490 gclog_or_tty->print_cr(" "
491 " minimum_free_percentage: %6.2f"
492 " maximum_used_percentage: %6.2f",
493 minimum_free_percentage,
494 maximum_used_percentage);
495 gclog_or_tty->print_cr(" "
496 " free_after_gc : %6.1fK"
497 " used_after_gc : %6.1fK"
498 " capacity_after_gc : %6.1fK",
499 free_after_gc / (double) K,
500 used_after_gc / (double) K,
501 capacity_after_gc / (double) K);
502 gclog_or_tty->print_cr(" "
503 " free_percentage: %6.2f",
504 free_percentage);
505 }
506
507 if (capacity_after_gc < minimum_desired_capacity) {
508 // If we have less free space than we want then expand
509 size_t expand_bytes = minimum_desired_capacity - capacity_after_gc;
510 // Don't expand unless it's significant
511 if (expand_bytes >= _min_heap_delta_bytes) {
512 expand(expand_bytes, 0); // safe if expansion fails
513 }
514 if (PrintGC && Verbose) {
515 gclog_or_tty->print_cr(" expanding:"
516 " minimum_desired_capacity: %6.1fK"
517 " expand_bytes: %6.1fK"
518 " _min_heap_delta_bytes: %6.1fK",
519 minimum_desired_capacity / (double) K,
520 expand_bytes / (double) K,
521 _min_heap_delta_bytes / (double) K);
522 }
523 return;
524 }
525
526 // No expansion, now see if we want to shrink
527 size_t shrink_bytes = 0;
528 // We would never want to shrink more than this
529 size_t max_shrink_bytes = capacity_after_gc - minimum_desired_capacity;
530
531 if (MaxHeapFreeRatio < 100) {
532 const double maximum_free_percentage = MaxHeapFreeRatio / 100.0;
533 const double minimum_used_percentage = 1.0 - maximum_free_percentage;
534 const double max_tmp = used_after_gc / minimum_used_percentage;
535 size_t maximum_desired_capacity = (size_t)MIN2(max_tmp, double(max_uintx));
536 maximum_desired_capacity = MAX2(maximum_desired_capacity,
537 spec()->init_size());
538 if (PrintGC && Verbose) {
539 gclog_or_tty->print_cr(" "
540 " maximum_free_percentage: %6.2f"
541 " minimum_used_percentage: %6.2f",
542 maximum_free_percentage,
543 minimum_used_percentage);
544 gclog_or_tty->print_cr(" "
545 " _capacity_at_prologue: %6.1fK"
546 " minimum_desired_capacity: %6.1fK"
547 " maximum_desired_capacity: %6.1fK",
548 _capacity_at_prologue / (double) K,
549 minimum_desired_capacity / (double) K,
550 maximum_desired_capacity / (double) K);
551 }
552 assert(minimum_desired_capacity <= maximum_desired_capacity,
553 "sanity check");
554
555 if (capacity_after_gc > maximum_desired_capacity) {
556 // Capacity too large, compute shrinking size
557 shrink_bytes = capacity_after_gc - maximum_desired_capacity;
558 // We don't want shrink all the way back to initSize if people call
559 // System.gc(), because some programs do that between "phases" and then
560 // we'd just have to grow the heap up again for the next phase. So we
561 // damp the shrinking: 0% on the first call, 10% on the second call, 40%
562 // on the third call, and 100% by the fourth call. But if we recompute
563 // size without shrinking, it goes back to 0%.
564 shrink_bytes = shrink_bytes / 100 * current_shrink_factor;
565 assert(shrink_bytes <= max_shrink_bytes, "invalid shrink size");
566 if (current_shrink_factor == 0) {
567 _shrink_factor = 10;
568 } else {
569 _shrink_factor = MIN2(current_shrink_factor * 4, (size_t) 100);
570 }
571 if (PrintGC && Verbose) {
572 gclog_or_tty->print_cr(" "
573 " shrinking:"
574 " initSize: %.1fK"
575 " maximum_desired_capacity: %.1fK",
576 spec()->init_size() / (double) K,
577 maximum_desired_capacity / (double) K);
578 gclog_or_tty->print_cr(" "
579 " shrink_bytes: %.1fK"
580 " current_shrink_factor: %d"
581 " new shrink factor: %d"
582 " _min_heap_delta_bytes: %.1fK",
583 shrink_bytes / (double) K,
584 current_shrink_factor,
585 _shrink_factor,
586 _min_heap_delta_bytes / (double) K);
587 }
588 }
589 }
590
591 if (capacity_after_gc > _capacity_at_prologue) {
592 // We might have expanded for promotions, in which case we might want to
593 // take back that expansion if there's room after GC. That keeps us from
594 // stretching the heap with promotions when there's plenty of room.
595 size_t expansion_for_promotion = capacity_after_gc - _capacity_at_prologue;
596 expansion_for_promotion = MIN2(expansion_for_promotion, max_shrink_bytes);
597 // We have two shrinking computations, take the largest
598 shrink_bytes = MAX2(shrink_bytes, expansion_for_promotion);
599 assert(shrink_bytes <= max_shrink_bytes, "invalid shrink size");
600 if (PrintGC && Verbose) {
601 gclog_or_tty->print_cr(" "
602 " aggressive shrinking:"
603 " _capacity_at_prologue: %.1fK"
604 " capacity_after_gc: %.1fK"
605 " expansion_for_promotion: %.1fK"
606 " shrink_bytes: %.1fK",
607 capacity_after_gc / (double) K,
608 _capacity_at_prologue / (double) K,
609 expansion_for_promotion / (double) K,
610 shrink_bytes / (double) K);
611 }
612 }
613 // Don't shrink unless it's significant
614 if (shrink_bytes >= _min_heap_delta_bytes) {
615 shrink(shrink_bytes);
616 }
617 }
618
619 // Currently nothing to do.
620 void CardGeneration::prepare_for_verify() {}
621
622
623 void OneContigSpaceCardGeneration::collect(bool full,
624 bool clear_all_soft_refs,
625 size_t size,
626 bool is_tlab) {
627 SpecializationStats::clear();
628 // Temporarily expand the span of our ref processor, so
629 // refs discovery is over the entire heap, not just this generation
630 ReferenceProcessorSpanMutator
631 x(ref_processor(), GenCollectedHeap::heap()->reserved_region());
632 GenMarkSweep::invoke_at_safepoint(_level, ref_processor(), clear_all_soft_refs);
633 SpecializationStats::print();
634 }
635
636 HeapWord*
637 OneContigSpaceCardGeneration::expand_and_allocate(size_t word_size,
638 bool is_tlab,
639 bool parallel) {
640 assert(!is_tlab, "OneContigSpaceCardGeneration does not support TLAB allocation");
641 if (parallel) {
642 MutexLocker x(ParGCRareEvent_lock);
643 HeapWord* result = NULL;
644 size_t byte_size = word_size * HeapWordSize;
645 while (true) {
646 expand(byte_size, _min_heap_delta_bytes);
647 if (GCExpandToAllocateDelayMillis > 0) {
648 os::sleep(Thread::current(), GCExpandToAllocateDelayMillis, false);
649 }
650 result = _the_space->par_allocate(word_size);
651 if ( result != NULL) {
652 return result;
653 } else {
654 // If there's not enough expansion space available, give up.
655 if (_virtual_space.uncommitted_size() < byte_size) {
656 return NULL;
657 }
658 // else try again
659 }
660 }
661 } else {
662 expand(word_size*HeapWordSize, _min_heap_delta_bytes);
663 return _the_space->allocate(word_size);
664 }
665 }
666
667 bool OneContigSpaceCardGeneration::expand(size_t bytes, size_t expand_bytes) {
668 GCMutexLocker x(ExpandHeap_lock);
669 return CardGeneration::expand(bytes, expand_bytes);
670 }
671
672
673 void OneContigSpaceCardGeneration::shrink(size_t bytes) {
674 assert_locked_or_safepoint(ExpandHeap_lock);
675 size_t size = ReservedSpace::page_align_size_down(bytes);
676 if (size > 0) {
677 shrink_by(size);
678 }
679 }
680
681
682 size_t OneContigSpaceCardGeneration::capacity() const {
683 return _the_space->capacity();
684 }
685
686
687 size_t OneContigSpaceCardGeneration::used() const {
688 return _the_space->used();
689 }
690
691
692 size_t OneContigSpaceCardGeneration::free() const {
693 return _the_space->free();
694 }
695
696 MemRegion OneContigSpaceCardGeneration::used_region() const {
697 return the_space()->used_region();
698 }
699
700 size_t OneContigSpaceCardGeneration::unsafe_max_alloc_nogc() const {
701 return _the_space->free();
702 }
703
704 size_t OneContigSpaceCardGeneration::contiguous_available() const {
705 return _the_space->free() + _virtual_space.uncommitted_size();
706 }
707
708 bool OneContigSpaceCardGeneration::grow_by(size_t bytes) {
709 assert_locked_or_safepoint(ExpandHeap_lock);
710 bool result = _virtual_space.expand_by(bytes);
711 if (result) {
712 size_t new_word_size =
713 heap_word_size(_virtual_space.committed_size());
714 MemRegion mr(_the_space->bottom(), new_word_size);
715 // Expand card table
716 Universe::heap()->barrier_set()->resize_covered_region(mr);
717 // Expand shared block offset array
718 _bts->resize(new_word_size);
719
720 // Fix for bug #4668531
721 if (ZapUnusedHeapArea) {
722 MemRegion mangle_region(_the_space->end(),
723 (HeapWord*)_virtual_space.high());
724 SpaceMangler::mangle_region(mangle_region);
725 }
726
727 // Expand space -- also expands space's BOT
728 // (which uses (part of) shared array above)
729 _the_space->set_end((HeapWord*)_virtual_space.high());
730
731 // update the space and generation capacity counters
732 update_counters();
733
734 if (Verbose && PrintGC) {
735 size_t new_mem_size = _virtual_space.committed_size();
736 size_t old_mem_size = new_mem_size - bytes;
737 gclog_or_tty->print_cr("Expanding %s from " SIZE_FORMAT "K by "
738 SIZE_FORMAT "K to " SIZE_FORMAT "K",
739 name(), old_mem_size/K, bytes/K, new_mem_size/K);
740 }
741 }
742 return result;
743 }
744
745
746 bool OneContigSpaceCardGeneration::grow_to_reserved() {
747 assert_locked_or_safepoint(ExpandHeap_lock);
748 bool success = true;
749 const size_t remaining_bytes = _virtual_space.uncommitted_size();
750 if (remaining_bytes > 0) {
751 success = grow_by(remaining_bytes);
752 DEBUG_ONLY(if (!success) warning("grow to reserved failed");)
753 }
754 return success;
755 }
756
757 void OneContigSpaceCardGeneration::shrink_by(size_t bytes) {
758 assert_locked_or_safepoint(ExpandHeap_lock);
759 // Shrink committed space
760 _virtual_space.shrink_by(bytes);
761 // Shrink space; this also shrinks the space's BOT
762 _the_space->set_end((HeapWord*) _virtual_space.high());
763 size_t new_word_size = heap_word_size(_the_space->capacity());
764 // Shrink the shared block offset array
765 _bts->resize(new_word_size);
766 MemRegion mr(_the_space->bottom(), new_word_size);
767 // Shrink the card table
768 Universe::heap()->barrier_set()->resize_covered_region(mr);
769
770 if (Verbose && PrintGC) {
771 size_t new_mem_size = _virtual_space.committed_size();
772 size_t old_mem_size = new_mem_size + bytes;
773 gclog_or_tty->print_cr("Shrinking %s from " SIZE_FORMAT "K to " SIZE_FORMAT "K",
774 name(), old_mem_size/K, new_mem_size/K);
775 }
776 }
777
778 // Currently nothing to do.
779 void OneContigSpaceCardGeneration::prepare_for_verify() {}
780
781
782 // Override for a card-table generation with one contiguous
783 // space. NOTE: For reasons that are lost in the fog of history,
784 // this code is used when you iterate over perm gen objects,
785 // even when one uses CDS, where the perm gen has a couple of
786 // other spaces; this is because CompactingPermGenGen derives
787 // from OneContigSpaceCardGeneration. This should be cleaned up,
788 // see CR 6897789..
789 void OneContigSpaceCardGeneration::object_iterate(ObjectClosure* blk) {
790 _the_space->object_iterate(blk);
791 }
792
793 void OneContigSpaceCardGeneration::space_iterate(SpaceClosure* blk,
794 bool usedOnly) {
795 blk->do_space(_the_space);
796 }
797
798 void OneContigSpaceCardGeneration::object_iterate_since_last_GC(ObjectClosure* blk) {
799 // Deal with delayed initialization of _the_space,
800 // and lack of initialization of _last_gc.
801 if (_last_gc.space() == NULL) {
802 assert(the_space() != NULL, "shouldn't be NULL");
803 _last_gc = the_space()->bottom_mark();
804 }
805 the_space()->object_iterate_from(_last_gc, blk);
806 }
807
808 void OneContigSpaceCardGeneration::younger_refs_iterate(OopsInGenClosure* blk) {
809 blk->set_generation(this);
810 younger_refs_in_space_iterate(_the_space, blk);
811 blk->reset_generation();
812 }
813
814 void OneContigSpaceCardGeneration::save_marks() {
815 _the_space->set_saved_mark();
816 }
817
818
819 void OneContigSpaceCardGeneration::reset_saved_marks() {
820 _the_space->reset_saved_mark();
821 }
822
823
824 bool OneContigSpaceCardGeneration::no_allocs_since_save_marks() {
825 return _the_space->saved_mark_at_top();
826 }
827
828 #define OneContig_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
829 \
830 void OneContigSpaceCardGeneration:: \
831 oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk) { \
832 blk->set_generation(this); \
833 _the_space->oop_since_save_marks_iterate##nv_suffix(blk); \
834 blk->reset_generation(); \
835 save_marks(); \
836 }
837
838 ALL_SINCE_SAVE_MARKS_CLOSURES(OneContig_SINCE_SAVE_MARKS_ITERATE_DEFN)
839
840 #undef OneContig_SINCE_SAVE_MARKS_ITERATE_DEFN
841
842
843 void OneContigSpaceCardGeneration::gc_epilogue(bool full) {
844 _last_gc = WaterMark(the_space(), the_space()->top());
845
846 // update the generation and space performance counters
847 update_counters();
848 if (ZapUnusedHeapArea) {
849 the_space()->check_mangled_unused_area_complete();
850 }
851 }
852
853 void OneContigSpaceCardGeneration::record_spaces_top() {
854 assert(ZapUnusedHeapArea, "Not mangling unused space");
855 the_space()->set_top_for_allocations();
856 }
857
858 void OneContigSpaceCardGeneration::verify() {
859 the_space()->verify();
860 }
861
862 void OneContigSpaceCardGeneration::print_on(outputStream* st) const {
863 Generation::print_on(st);
864 st->print(" the");
865 the_space()->print_on(st);
866 }