1 /*
2 * Copyright (c) 2001, 2014, 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 "code/nmethod.hpp"
27 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
28 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
29 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
30 #include "gc_implementation/g1/heapRegion.inline.hpp"
31 #include "gc_implementation/g1/heapRegionBounds.inline.hpp"
32 #include "gc_implementation/g1/heapRegionRemSet.hpp"
33 #include "gc_implementation/g1/heapRegionManager.inline.hpp"
34 #include "gc_implementation/shared/liveRange.hpp"
35 #include "memory/genOopClosures.inline.hpp"
36 #include "memory/iterator.hpp"
37 #include "memory/space.inline.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "runtime/atomic.inline.hpp"
40 #include "runtime/orderAccess.inline.hpp"
41
42 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
43
44 int HeapRegion::LogOfHRGrainBytes = 0;
45 int HeapRegion::LogOfHRGrainWords = 0;
46 size_t HeapRegion::GrainBytes = 0;
47 size_t HeapRegion::GrainWords = 0;
48 size_t HeapRegion::CardsPerRegion = 0;
49
50 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
51 HeapRegion* hr,
52 G1ParPushHeapRSClosure* cl,
53 CardTableModRefBS::PrecisionStyle precision) :
54 DirtyCardToOopClosure(hr, cl, precision, NULL),
55 _hr(hr), _rs_scan(cl), _g1(g1) { }
56
57 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
58 OopClosure* oc) :
59 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
60
61 void HeapRegionDCTOC::walk_mem_region(MemRegion mr,
62 HeapWord* bottom,
63 HeapWord* top) {
64 G1CollectedHeap* g1h = _g1;
65 size_t oop_size;
66 HeapWord* cur = bottom;
67
68 // Start filtering what we add to the remembered set. If the object is
69 // not considered dead, either because it is marked (in the mark bitmap)
70 // or it was allocated after marking finished, then we add it. Otherwise
71 // we can safely ignore the object.
72 if (!g1h->is_obj_dead(oop(cur), _hr)) {
73 oop_size = oop(cur)->oop_iterate(_rs_scan, mr);
74 } else {
75 oop_size = _hr->block_size(cur);
76 }
77
78 cur += oop_size;
79
80 if (cur < top) {
81 oop cur_oop = oop(cur);
82 oop_size = _hr->block_size(cur);
83 HeapWord* next_obj = cur + oop_size;
84 while (next_obj < top) {
85 // Keep filtering the remembered set.
86 if (!g1h->is_obj_dead(cur_oop, _hr)) {
87 // Bottom lies entirely below top, so we can call the
88 // non-memRegion version of oop_iterate below.
89 cur_oop->oop_iterate(_rs_scan);
90 }
91 cur = next_obj;
92 cur_oop = oop(cur);
93 oop_size = _hr->block_size(cur);
94 next_obj = cur + oop_size;
95 }
96
97 // Last object. Need to do dead-obj filtering here too.
98 if (!g1h->is_obj_dead(oop(cur), _hr)) {
99 oop(cur)->oop_iterate(_rs_scan, mr);
100 }
101 }
102 }
103
104 size_t HeapRegion::max_region_size() {
105 return HeapRegionBounds::max_size();
106 }
107
108 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
109 uintx region_size = G1HeapRegionSize;
110 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
111 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
112 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(),
113 (uintx) HeapRegionBounds::min_size());
114 }
115
116 int region_size_log = log2_long((jlong) region_size);
117 // Recalculate the region size to make sure it's a power of
118 // 2. This means that region_size is the largest power of 2 that's
119 // <= what we've calculated so far.
120 region_size = ((uintx)1 << region_size_log);
121
122 // Now make sure that we don't go over or under our limits.
123 if (region_size < HeapRegionBounds::min_size()) {
124 region_size = HeapRegionBounds::min_size();
125 } else if (region_size > HeapRegionBounds::max_size()) {
126 region_size = HeapRegionBounds::max_size();
127 }
128
129 // And recalculate the log.
130 region_size_log = log2_long((jlong) region_size);
131
132 // Now, set up the globals.
133 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
134 LogOfHRGrainBytes = region_size_log;
135
136 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
137 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
138
139 guarantee(GrainBytes == 0, "we should only set it once");
140 // The cast to int is safe, given that we've bounded region_size by
141 // MIN_REGION_SIZE and MAX_REGION_SIZE.
142 GrainBytes = (size_t)region_size;
143
144 guarantee(GrainWords == 0, "we should only set it once");
145 GrainWords = GrainBytes >> LogHeapWordSize;
146 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
147
148 guarantee(CardsPerRegion == 0, "we should only set it once");
149 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
150 }
151
152 void HeapRegion::reset_after_compaction() {
153 G1OffsetTableContigSpace::reset_after_compaction();
154 // After a compaction the mark bitmap is invalid, so we must
155 // treat all objects as being inside the unmarked area.
156 zero_marked_bytes();
157 init_top_at_mark_start();
158 }
159
160 void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
161 assert(_humongous_start_region == NULL,
162 "we should have already filtered out humongous regions");
163 assert(_end == orig_end(),
164 "we should have already filtered out humongous regions");
165
166 set_allocation_context(AllocationContext::system());
167 set_young_index_in_cset(-1);
168 uninstall_surv_rate_group();
169 set_free();
170 reset_pre_dummy_top();
171
172 if (!par) {
173 // If this is parallel, this will be done later.
174 HeapRegionRemSet* hrrs = rem_set();
175 if (locked) {
176 hrrs->clear_locked();
177 } else {
178 hrrs->clear();
179 }
180 }
181 zero_marked_bytes();
182
183 _offsets.resize(HeapRegion::GrainWords);
184 init_top_at_mark_start();
185 if (clear_space) clear(SpaceDecorator::Mangle);
186 }
187
188 void HeapRegion::par_clear() {
189 assert(used() == 0, "the region should have been already cleared");
190 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
191 HeapRegionRemSet* hrrs = rem_set();
192 hrrs->clear();
193 CardTableModRefBS* ct_bs =
194 (CardTableModRefBS*)G1CollectedHeap::heap()->barrier_set();
195 ct_bs->clear(MemRegion(bottom(), end()));
196 }
197
198 void HeapRegion::calc_gc_efficiency() {
199 // GC efficiency is the ratio of how much space would be
200 // reclaimed over how long we predict it would take to reclaim it.
201 G1CollectedHeap* g1h = G1CollectedHeap::heap();
202 G1CollectorPolicy* g1p = g1h->g1_policy();
203
204 // Retrieve a prediction of the elapsed time for this region for
205 // a mixed gc because the region will only be evacuated during a
206 // mixed gc.
207 double region_elapsed_time_ms =
208 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
209 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
210 }
211
212 void HeapRegion::set_starts_humongous(HeapWord* new_top, HeapWord* new_end) {
213 assert(!is_humongous(), "sanity / pre-condition");
214 assert(end() == orig_end(),
215 "Should be normal before the humongous object allocation");
216 assert(top() == bottom(), "should be empty");
217 assert(bottom() <= new_top && new_top <= new_end, "pre-condition");
218
219 _type.set_starts_humongous();
220 _humongous_start_region = this;
221
222 set_end(new_end);
223 _offsets.set_for_starts_humongous(new_top);
224 }
225
226 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) {
227 assert(!is_humongous(), "sanity / pre-condition");
228 assert(end() == orig_end(),
229 "Should be normal before the humongous object allocation");
230 assert(top() == bottom(), "should be empty");
231 assert(first_hr->is_starts_humongous(), "pre-condition");
232
233 _type.set_continues_humongous();
234 _humongous_start_region = first_hr;
235 }
236
237 void HeapRegion::clear_humongous() {
238 assert(is_humongous(), "pre-condition");
239
240 if (is_starts_humongous()) {
241 assert(top() <= end(), "pre-condition");
242 set_end(orig_end());
243 if (top() > end()) {
244 // at least one "continues humongous" region after it
245 set_top(end());
246 }
247 } else {
248 // continues humongous
249 assert(end() == orig_end(), "sanity");
250 }
251
252 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
253 _humongous_start_region = NULL;
254 }
255
256 HeapRegion::HeapRegion(uint hrm_index,
257 G1BlockOffsetSharedArray* sharedOffsetArray,
258 MemRegion mr) :
259 G1OffsetTableContigSpace(sharedOffsetArray, mr),
260 _hrm_index(hrm_index),
261 _allocation_context(AllocationContext::system()),
262 _humongous_start_region(NULL),
263 _next_in_special_set(NULL),
264 _evacuation_failed(false),
265 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
266 _next_young_region(NULL),
267 _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL),
268 #ifdef ASSERT
269 _containing_set(NULL),
270 #endif // ASSERT
271 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
272 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
273 _predicted_bytes_to_copy(0)
274 {
275 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
276 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
277
278 initialize(mr);
279 }
280
281 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
282 assert(_rem_set->is_empty(), "Remembered set must be empty");
283
284 G1OffsetTableContigSpace::initialize(mr, clear_space, mangle_space);
285
286 hr_clear(false /*par*/, false /*clear_space*/);
287 set_top(bottom());
288 record_timestamp();
289
290 assert(mr.end() == orig_end(),
291 err_msg("Given region end address " PTR_FORMAT " should match exactly "
292 "bottom plus one region size, i.e. " PTR_FORMAT,
293 p2i(mr.end()), p2i(orig_end())));
294 }
295
296 CompactibleSpace* HeapRegion::next_compaction_space() const {
297 return G1CollectedHeap::heap()->next_compaction_region(this);
298 }
299
300 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
301 bool during_conc_mark) {
302 // We always recreate the prev marking info and we'll explicitly
303 // mark all objects we find to be self-forwarded on the prev
304 // bitmap. So all objects need to be below PTAMS.
305 _prev_marked_bytes = 0;
306
307 if (during_initial_mark) {
308 // During initial-mark, we'll also explicitly mark all objects
309 // we find to be self-forwarded on the next bitmap. So all
310 // objects need to be below NTAMS.
311 _next_top_at_mark_start = top();
312 _next_marked_bytes = 0;
313 } else if (during_conc_mark) {
314 // During concurrent mark, all objects in the CSet (including
315 // the ones we find to be self-forwarded) are implicitly live.
316 // So all objects need to be above NTAMS.
317 _next_top_at_mark_start = bottom();
318 _next_marked_bytes = 0;
319 }
320 }
321
322 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
323 bool during_conc_mark,
324 size_t marked_bytes) {
325 assert(0 <= marked_bytes && marked_bytes <= used(),
326 err_msg("marked: "SIZE_FORMAT" used: "SIZE_FORMAT,
327 marked_bytes, used()));
328 _prev_top_at_mark_start = top();
329 _prev_marked_bytes = marked_bytes;
330 }
331
332 HeapWord*
333 HeapRegion::object_iterate_mem_careful(MemRegion mr,
334 ObjectClosure* cl) {
335 G1CollectedHeap* g1h = G1CollectedHeap::heap();
336 // We used to use "block_start_careful" here. But we're actually happy
337 // to update the BOT while we do this...
338 HeapWord* cur = block_start(mr.start());
339 mr = mr.intersection(used_region());
340 if (mr.is_empty()) return NULL;
341 // Otherwise, find the obj that extends onto mr.start().
342
343 assert(cur <= mr.start()
344 && (oop(cur)->klass_or_null() == NULL ||
345 cur + oop(cur)->size() > mr.start()),
346 "postcondition of block_start");
347 oop obj;
348 while (cur < mr.end()) {
349 obj = oop(cur);
350 if (obj->klass_or_null() == NULL) {
351 // Ran into an unparseable point.
352 return cur;
353 } else if (!g1h->is_obj_dead(obj)) {
354 cl->do_object(obj);
355 }
356 cur += block_size(cur);
357 }
358 return NULL;
359 }
360
361 HeapWord*
362 HeapRegion::
363 oops_on_card_seq_iterate_careful(MemRegion mr,
364 FilterOutOfRegionClosure* cl,
365 bool filter_young,
366 jbyte* card_ptr) {
367 // Currently, we should only have to clean the card if filter_young
368 // is true and vice versa.
369 if (filter_young) {
370 assert(card_ptr != NULL, "pre-condition");
371 } else {
372 assert(card_ptr == NULL, "pre-condition");
373 }
374 G1CollectedHeap* g1h = G1CollectedHeap::heap();
375
376 // If we're within a stop-world GC, then we might look at a card in a
377 // GC alloc region that extends onto a GC LAB, which may not be
378 // parseable. Stop such at the "scan_top" of the region.
379 if (g1h->is_gc_active()) {
380 mr = mr.intersection(MemRegion(bottom(), scan_top()));
381 } else {
382 mr = mr.intersection(used_region());
383 }
384 if (mr.is_empty()) return NULL;
385 // Otherwise, find the obj that extends onto mr.start().
386
387 // The intersection of the incoming mr (for the card) and the
388 // allocated part of the region is non-empty. This implies that
389 // we have actually allocated into this region. The code in
390 // G1CollectedHeap.cpp that allocates a new region sets the
391 // is_young tag on the region before allocating. Thus we
392 // safely know if this region is young.
393 if (is_young() && filter_young) {
394 return NULL;
395 }
396
397 assert(!is_young(), "check value of filter_young");
398
399 // We can only clean the card here, after we make the decision that
400 // the card is not young. And we only clean the card if we have been
401 // asked to (i.e., card_ptr != NULL).
402 if (card_ptr != NULL) {
403 *card_ptr = CardTableModRefBS::clean_card_val();
404 // We must complete this write before we do any of the reads below.
405 OrderAccess::storeload();
406 }
407
408 // Cache the boundaries of the memory region in some const locals
409 HeapWord* const start = mr.start();
410 HeapWord* const end = mr.end();
411
412 // We used to use "block_start_careful" here. But we're actually happy
413 // to update the BOT while we do this...
414 HeapWord* cur = block_start(start);
415 assert(cur <= start, "Postcondition");
416
417 oop obj;
418
419 HeapWord* next = cur;
420 while (next <= start) {
421 cur = next;
422 obj = oop(cur);
423 if (obj->klass_or_null() == NULL) {
424 // Ran into an unparseable point.
425 return cur;
426 }
427 // Otherwise...
428 next = cur + block_size(cur);
429 }
430
431 // If we finish the above loop...We have a parseable object that
432 // begins on or before the start of the memory region, and ends
433 // inside or spans the entire region.
434
435 assert(obj == oop(cur), "sanity");
436 assert(cur <= start, "Loop postcondition");
437 assert(obj->klass_or_null() != NULL, "Loop postcondition");
438 assert((cur + block_size(cur)) > start, "Loop postcondition");
439
440 if (!g1h->is_obj_dead(obj)) {
441 obj->oop_iterate(cl, mr);
442 }
443
444 while (cur < end) {
445 obj = oop(cur);
446 if (obj->klass_or_null() == NULL) {
447 // Ran into an unparseable point.
448 return cur;
449 };
450
451 // Otherwise:
452 next = cur + block_size(cur);
453
454 if (!g1h->is_obj_dead(obj)) {
455 if (next < end || !obj->is_objArray()) {
456 // This object either does not span the MemRegion
457 // boundary, or if it does it's not an array.
458 // Apply closure to whole object.
459 obj->oop_iterate(cl);
460 } else {
461 // This obj is an array that spans the boundary.
462 // Stop at the boundary.
463 obj->oop_iterate(cl, mr);
464 }
465 }
466 cur = next;
467 }
468 return NULL;
469 }
470
471 // Code roots support
472
473 void HeapRegion::add_strong_code_root(nmethod* nm) {
474 HeapRegionRemSet* hrrs = rem_set();
475 hrrs->add_strong_code_root(nm);
476 }
477
478 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
479 assert_locked_or_safepoint(CodeCache_lock);
480 HeapRegionRemSet* hrrs = rem_set();
481 hrrs->add_strong_code_root_locked(nm);
482 }
483
484 void HeapRegion::remove_strong_code_root(nmethod* nm) {
485 HeapRegionRemSet* hrrs = rem_set();
486 hrrs->remove_strong_code_root(nm);
487 }
488
489 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
490 HeapRegionRemSet* hrrs = rem_set();
491 hrrs->strong_code_roots_do(blk);
492 }
493
494 class VerifyStrongCodeRootOopClosure: public OopClosure {
495 const HeapRegion* _hr;
496 nmethod* _nm;
497 bool _failures;
498 bool _has_oops_in_region;
499
500 template <class T> void do_oop_work(T* p) {
501 T heap_oop = oopDesc::load_heap_oop(p);
502 if (!oopDesc::is_null(heap_oop)) {
503 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
504
505 // Note: not all the oops embedded in the nmethod are in the
506 // current region. We only look at those which are.
507 if (_hr->is_in(obj)) {
508 // Object is in the region. Check that its less than top
509 if (_hr->top() <= (HeapWord*)obj) {
510 // Object is above top
511 gclog_or_tty->print_cr("Object "PTR_FORMAT" in region "
512 "["PTR_FORMAT", "PTR_FORMAT") is above "
513 "top "PTR_FORMAT,
514 (void *)obj, _hr->bottom(), _hr->end(), _hr->top());
515 _failures = true;
516 return;
517 }
518 // Nmethod has at least one oop in the current region
519 _has_oops_in_region = true;
520 }
521 }
522 }
523
524 public:
525 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
526 _hr(hr), _failures(false), _has_oops_in_region(false) {}
527
528 void do_oop(narrowOop* p) { do_oop_work(p); }
529 void do_oop(oop* p) { do_oop_work(p); }
530
531 bool failures() { return _failures; }
532 bool has_oops_in_region() { return _has_oops_in_region; }
533 };
534
535 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
536 const HeapRegion* _hr;
537 bool _failures;
538 public:
539 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
540 _hr(hr), _failures(false) {}
541
542 void do_code_blob(CodeBlob* cb) {
543 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
544 if (nm != NULL) {
545 // Verify that the nemthod is live
546 if (!nm->is_alive()) {
547 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has dead nmethod "
548 PTR_FORMAT" in its strong code roots",
549 _hr->bottom(), _hr->end(), nm);
550 _failures = true;
551 } else {
552 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
553 nm->oops_do(&oop_cl);
554 if (!oop_cl.has_oops_in_region()) {
555 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has nmethod "
556 PTR_FORMAT" in its strong code roots "
557 "with no pointers into region",
558 _hr->bottom(), _hr->end(), nm);
559 _failures = true;
560 } else if (oop_cl.failures()) {
561 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has other "
562 "failures for nmethod "PTR_FORMAT,
563 _hr->bottom(), _hr->end(), nm);
564 _failures = true;
565 }
566 }
567 }
568 }
569
570 bool failures() { return _failures; }
571 };
572
573 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
574 if (!G1VerifyHeapRegionCodeRoots) {
575 // We're not verifying code roots.
576 return;
577 }
578 if (vo == VerifyOption_G1UseMarkWord) {
579 // Marking verification during a full GC is performed after class
580 // unloading, code cache unloading, etc so the strong code roots
581 // attached to each heap region are in an inconsistent state. They won't
582 // be consistent until the strong code roots are rebuilt after the
583 // actual GC. Skip verifying the strong code roots in this particular
584 // time.
585 assert(VerifyDuringGC, "only way to get here");
586 return;
587 }
588
589 HeapRegionRemSet* hrrs = rem_set();
590 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
591
592 // if this region is empty then there should be no entries
593 // on its strong code root list
594 if (is_empty()) {
595 if (strong_code_roots_length > 0) {
596 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is empty "
597 "but has "SIZE_FORMAT" code root entries",
598 bottom(), end(), strong_code_roots_length);
599 *failures = true;
600 }
601 return;
602 }
603
604 if (is_continues_humongous()) {
605 if (strong_code_roots_length > 0) {
606 gclog_or_tty->print_cr("region "HR_FORMAT" is a continuation of a humongous "
607 "region but has "SIZE_FORMAT" code root entries",
608 HR_FORMAT_PARAMS(this), strong_code_roots_length);
609 *failures = true;
610 }
611 return;
612 }
613
614 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
615 strong_code_roots_do(&cb_cl);
616
617 if (cb_cl.failures()) {
618 *failures = true;
619 }
620 }
621
622 void HeapRegion::print() const { print_on(gclog_or_tty); }
623 void HeapRegion::print_on(outputStream* st) const {
624 st->print("AC%4u", allocation_context());
625
626 st->print(" %2s", get_short_type_str());
627 if (in_collection_set())
628 st->print(" CS");
629 else
630 st->print(" ");
631 st->print(" TS %5d", _gc_time_stamp);
632 st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT,
633 prev_top_at_mark_start(), next_top_at_mark_start());
634 G1OffsetTableContigSpace::print_on(st);
635 }
636
637 class VerifyLiveClosure: public OopClosure {
638 private:
639 G1CollectedHeap* _g1h;
640 CardTableModRefBS* _bs;
641 oop _containing_obj;
642 bool _failures;
643 int _n_failures;
644 VerifyOption _vo;
645 public:
646 // _vo == UsePrevMarking -> use "prev" marking information,
647 // _vo == UseNextMarking -> use "next" marking information,
648 // _vo == UseMarkWord -> use mark word from object header.
649 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) :
650 _g1h(g1h), _bs(NULL), _containing_obj(NULL),
651 _failures(false), _n_failures(0), _vo(vo)
652 {
653 BarrierSet* bs = _g1h->barrier_set();
654 if (bs->is_a(BarrierSet::CardTableModRef))
655 _bs = (CardTableModRefBS*)bs;
656 }
657
658 void set_containing_obj(oop obj) {
659 _containing_obj = obj;
660 }
661
662 bool failures() { return _failures; }
663 int n_failures() { return _n_failures; }
664
665 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
666 virtual void do_oop( oop* p) { do_oop_work(p); }
667
668 void print_object(outputStream* out, oop obj) {
669 #ifdef PRODUCT
670 Klass* k = obj->klass();
671 const char* class_name = InstanceKlass::cast(k)->external_name();
672 out->print_cr("class name %s", class_name);
673 #else // PRODUCT
674 obj->print_on(out);
675 #endif // PRODUCT
676 }
677
678 template <class T>
679 void do_oop_work(T* p) {
680 assert(_containing_obj != NULL, "Precondition");
681 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
682 "Precondition");
683 T heap_oop = oopDesc::load_heap_oop(p);
684 if (!oopDesc::is_null(heap_oop)) {
685 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
686 bool failed = false;
687 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
688 MutexLockerEx x(ParGCRareEvent_lock,
689 Mutex::_no_safepoint_check_flag);
690
691 if (!_failures) {
692 gclog_or_tty->cr();
693 gclog_or_tty->print_cr("----------");
694 }
695 if (!_g1h->is_in_closed_subset(obj)) {
696 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
697 gclog_or_tty->print_cr("Field "PTR_FORMAT
698 " of live obj "PTR_FORMAT" in region "
699 "["PTR_FORMAT", "PTR_FORMAT")",
700 p, (void*) _containing_obj,
701 from->bottom(), from->end());
702 print_object(gclog_or_tty, _containing_obj);
703 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" not in the heap",
704 (void*) obj);
705 } else {
706 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
707 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
708 gclog_or_tty->print_cr("Field "PTR_FORMAT
709 " of live obj "PTR_FORMAT" in region "
710 "["PTR_FORMAT", "PTR_FORMAT")",
711 p, (void*) _containing_obj,
712 from->bottom(), from->end());
713 print_object(gclog_or_tty, _containing_obj);
714 gclog_or_tty->print_cr("points to dead obj "PTR_FORMAT" in region "
715 "["PTR_FORMAT", "PTR_FORMAT")",
716 (void*) obj, to->bottom(), to->end());
717 print_object(gclog_or_tty, obj);
718 }
719 gclog_or_tty->print_cr("----------");
720 gclog_or_tty->flush();
721 _failures = true;
722 failed = true;
723 _n_failures++;
724 }
725
726 if (!_g1h->full_collection() || G1VerifyRSetsDuringFullGC) {
727 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
728 HeapRegion* to = _g1h->heap_region_containing(obj);
729 if (from != NULL && to != NULL &&
730 from != to &&
731 !to->is_humongous()) {
732 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
733 jbyte cv_field = *_bs->byte_for_const(p);
734 const jbyte dirty = CardTableModRefBS::dirty_card_val();
735
736 bool is_bad = !(from->is_young()
737 || to->rem_set()->contains_reference(p)
738 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
739 (_containing_obj->is_objArray() ?
740 cv_field == dirty
741 : cv_obj == dirty || cv_field == dirty));
742 if (is_bad) {
743 MutexLockerEx x(ParGCRareEvent_lock,
744 Mutex::_no_safepoint_check_flag);
745
746 if (!_failures) {
747 gclog_or_tty->cr();
748 gclog_or_tty->print_cr("----------");
749 }
750 gclog_or_tty->print_cr("Missing rem set entry:");
751 gclog_or_tty->print_cr("Field "PTR_FORMAT" "
752 "of obj "PTR_FORMAT", "
753 "in region "HR_FORMAT,
754 p, (void*) _containing_obj,
755 HR_FORMAT_PARAMS(from));
756 _containing_obj->print_on(gclog_or_tty);
757 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" "
758 "in region "HR_FORMAT,
759 (void*) obj,
760 HR_FORMAT_PARAMS(to));
761 obj->print_on(gclog_or_tty);
762 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
763 cv_obj, cv_field);
764 gclog_or_tty->print_cr("----------");
765 gclog_or_tty->flush();
766 _failures = true;
767 if (!failed) _n_failures++;
768 }
769 }
770 }
771 }
772 }
773 };
774
775 // This really ought to be commoned up into OffsetTableContigSpace somehow.
776 // We would need a mechanism to make that code skip dead objects.
777
778 void HeapRegion::verify(VerifyOption vo,
779 bool* failures) const {
780 G1CollectedHeap* g1 = G1CollectedHeap::heap();
781 *failures = false;
782 HeapWord* p = bottom();
783 HeapWord* prev_p = NULL;
784 VerifyLiveClosure vl_cl(g1, vo);
785 bool is_region_humongous = is_humongous();
786 size_t object_num = 0;
787 while (p < top()) {
788 oop obj = oop(p);
789 size_t obj_size = block_size(p);
790 object_num += 1;
791
792 if (is_region_humongous != g1->is_humongous(obj_size) &&
793 !g1->is_obj_dead(obj, this)) { // Dead objects may have bigger block_size since they span several objects.
794 gclog_or_tty->print_cr("obj "PTR_FORMAT" is of %shumongous size ("
795 SIZE_FORMAT" words) in a %shumongous region",
796 p, g1->is_humongous(obj_size) ? "" : "non-",
797 obj_size, is_region_humongous ? "" : "non-");
798 *failures = true;
799 return;
800 }
801
802 if (!g1->is_obj_dead_cond(obj, this, vo)) {
803 if (obj->is_oop()) {
804 Klass* klass = obj->klass();
805 bool is_metaspace_object = Metaspace::contains(klass) ||
806 (vo == VerifyOption_G1UsePrevMarking &&
807 ClassLoaderDataGraph::unload_list_contains(klass));
808 if (!is_metaspace_object) {
809 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
810 "not metadata", klass, (void *)obj);
811 *failures = true;
812 return;
813 } else if (!klass->is_klass()) {
814 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
815 "not a klass", klass, (void *)obj);
816 *failures = true;
817 return;
818 } else {
819 vl_cl.set_containing_obj(obj);
820 obj->oop_iterate_no_header(&vl_cl);
821 if (vl_cl.failures()) {
822 *failures = true;
823 }
824 if (G1MaxVerifyFailures >= 0 &&
825 vl_cl.n_failures() >= G1MaxVerifyFailures) {
826 return;
827 }
828 }
829 } else {
830 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", (void *)obj);
831 *failures = true;
832 return;
833 }
834 }
835 prev_p = p;
836 p += obj_size;
837 }
838
839 if (!is_young() && !is_empty()) {
840 _offsets.verify();
841 }
842
843 if (p != top()) {
844 gclog_or_tty->print_cr("end of last object "PTR_FORMAT" "
845 "does not match top "PTR_FORMAT, p, top());
846 *failures = true;
847 return;
848 }
849
850 HeapWord* the_end = end();
851 assert(p == top(), "it should still hold");
852 // Do some extra BOT consistency checking for addresses in the
853 // range [top, end). BOT look-ups in this range should yield
854 // top. No point in doing that if top == end (there's nothing there).
855 if (p < the_end) {
856 // Look up top
857 HeapWord* addr_1 = p;
858 HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
859 if (b_start_1 != p) {
860 gclog_or_tty->print_cr("BOT look up for top: "PTR_FORMAT" "
861 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
862 addr_1, b_start_1, p);
863 *failures = true;
864 return;
865 }
866
867 // Look up top + 1
868 HeapWord* addr_2 = p + 1;
869 if (addr_2 < the_end) {
870 HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
871 if (b_start_2 != p) {
872 gclog_or_tty->print_cr("BOT look up for top + 1: "PTR_FORMAT" "
873 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
874 addr_2, b_start_2, p);
875 *failures = true;
876 return;
877 }
878 }
879
880 // Look up an address between top and end
881 size_t diff = pointer_delta(the_end, p) / 2;
882 HeapWord* addr_3 = p + diff;
883 if (addr_3 < the_end) {
884 HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
885 if (b_start_3 != p) {
886 gclog_or_tty->print_cr("BOT look up for top + diff: "PTR_FORMAT" "
887 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
888 addr_3, b_start_3, p);
889 *failures = true;
890 return;
891 }
892 }
893
894 // Look up end - 1
895 HeapWord* addr_4 = the_end - 1;
896 HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
897 if (b_start_4 != p) {
898 gclog_or_tty->print_cr("BOT look up for end - 1: "PTR_FORMAT" "
899 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
900 addr_4, b_start_4, p);
901 *failures = true;
902 return;
903 }
904 }
905
906 if (is_region_humongous && object_num > 1) {
907 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous "
908 "but has "SIZE_FORMAT", objects",
909 bottom(), end(), object_num);
910 *failures = true;
911 return;
912 }
913
914 verify_strong_code_roots(vo, failures);
915 }
916
917 void HeapRegion::verify() const {
918 bool dummy = false;
919 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
920 }
921
922 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
923 scan_and_forward(this, cp);
924 }
925
926 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
927 // away eventually.
928
929 void G1OffsetTableContigSpace::clear(bool mangle_space) {
930 set_top(bottom());
931 _scan_top = bottom();
932 CompactibleSpace::clear(mangle_space);
933 reset_bot();
934 }
935
936 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
937 Space::set_bottom(new_bottom);
938 _offsets.set_bottom(new_bottom);
939 }
940
941 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
942 Space::set_end(new_end);
943 _offsets.resize(new_end - bottom());
944 }
945
946 void G1OffsetTableContigSpace::print() const {
947 print_short();
948 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
949 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
950 bottom(), top(), _offsets.threshold(), end());
951 }
952
953 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
954 return _offsets.initialize_threshold();
955 }
956
957 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
958 HeapWord* end) {
959 _offsets.alloc_block(start, end);
960 return _offsets.threshold();
961 }
962
963 HeapWord* G1OffsetTableContigSpace::scan_top() const {
964 G1CollectedHeap* g1h = G1CollectedHeap::heap();
965 HeapWord* local_top = top();
966 OrderAccess::loadload();
967 const unsigned local_time_stamp = _gc_time_stamp;
968 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
969 if (local_time_stamp < g1h->get_gc_time_stamp()) {
970 return local_top;
971 } else {
972 return _scan_top;
973 }
974 }
975
976 void G1OffsetTableContigSpace::record_timestamp() {
977 G1CollectedHeap* g1h = G1CollectedHeap::heap();
978 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
979
980 if (_gc_time_stamp < curr_gc_time_stamp) {
981 // Setting the time stamp here tells concurrent readers to look at
982 // scan_top to know the maximum allowed address to look at.
983
984 // scan_top should be bottom for all regions except for the
985 // retained old alloc region which should have scan_top == top
986 HeapWord* st = _scan_top;
987 guarantee(st == _bottom || st == _top, "invariant");
988
989 _gc_time_stamp = curr_gc_time_stamp;
990 }
991 }
992
993 void G1OffsetTableContigSpace::record_retained_region() {
994 // scan_top is the maximum address where it's safe for the next gc to
995 // scan this region.
996 _scan_top = top();
997 }
998
999 void G1OffsetTableContigSpace::safe_object_iterate(ObjectClosure* blk) {
1000 object_iterate(blk);
1001 }
1002
1003 void G1OffsetTableContigSpace::object_iterate(ObjectClosure* blk) {
1004 HeapWord* p = bottom();
1005 while (p < top()) {
1006 if (block_is_obj(p)) {
1007 blk->do_object(oop(p));
1008 }
1009 p += block_size(p);
1010 }
1011 }
1012
1013 G1OffsetTableContigSpace::
1014 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
1015 MemRegion mr) :
1016 _offsets(sharedOffsetArray, mr),
1017 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
1018 _gc_time_stamp(0)
1019 {
1020 _offsets.set_space(this);
1021 }
1022
1023 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
1024 CompactibleSpace::initialize(mr, clear_space, mangle_space);
1025 _top = bottom();
1026 _scan_top = bottom();
1027 set_saved_mark_word(NULL);
1028 reset_bot();
1029 }
1030