1 /*
2 * Copyright (c) 2001, 2015, 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/g1/g1BlockOffsetTable.inline.hpp"
28 #include "gc/g1/g1CollectedHeap.inline.hpp"
29 #include "gc/g1/g1OopClosures.inline.hpp"
30 #include "gc/g1/heapRegion.inline.hpp"
31 #include "gc/g1/heapRegionBounds.inline.hpp"
32 #include "gc/g1/heapRegionManager.inline.hpp"
33 #include "gc/g1/heapRegionRemSet.hpp"
34 #include "gc/shared/genOopClosures.inline.hpp"
35 #include "gc/shared/liveRange.hpp"
36 #include "gc/shared/space.inline.hpp"
37 #include "logging/log.hpp"
38 #include "memory/iterator.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "runtime/atomic.inline.hpp"
41 #include "runtime/orderAccess.inline.hpp"
42
43 int HeapRegion::LogOfHRGrainBytes = 0;
44 int HeapRegion::LogOfHRGrainWords = 0;
45 size_t HeapRegion::GrainBytes = 0;
46 size_t HeapRegion::GrainWords = 0;
47 size_t HeapRegion::CardsPerRegion = 0;
48
49 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
50 HeapRegion* hr,
51 G1ParPushHeapRSClosure* cl,
52 CardTableModRefBS::PrecisionStyle precision) :
53 DirtyCardToOopClosure(hr, cl, precision, NULL),
54 _hr(hr), _rs_scan(cl), _g1(g1) { }
55
56 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
57 OopClosure* oc) :
58 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
59
60 void HeapRegionDCTOC::walk_mem_region(MemRegion mr,
61 HeapWord* bottom,
62 HeapWord* top) {
63 G1CollectedHeap* g1h = _g1;
64 size_t oop_size;
65 HeapWord* cur = bottom;
66
67 // Start filtering what we add to the remembered set. If the object is
68 // not considered dead, either because it is marked (in the mark bitmap)
69 // or it was allocated after marking finished, then we add it. Otherwise
70 // we can safely ignore the object.
71 if (!g1h->is_obj_dead(oop(cur), _hr)) {
72 oop_size = oop(cur)->oop_iterate_size(_rs_scan, mr);
73 } else {
74 oop_size = _hr->block_size(cur);
75 }
76
77 cur += oop_size;
78
79 if (cur < top) {
80 oop cur_oop = oop(cur);
81 oop_size = _hr->block_size(cur);
82 HeapWord* next_obj = cur + oop_size;
83 while (next_obj < top) {
84 // Keep filtering the remembered set.
85 if (!g1h->is_obj_dead(cur_oop, _hr)) {
86 // Bottom lies entirely below top, so we can call the
87 // non-memRegion version of oop_iterate below.
88 cur_oop->oop_iterate(_rs_scan);
89 }
90 cur = next_obj;
91 cur_oop = oop(cur);
92 oop_size = _hr->block_size(cur);
93 next_obj = cur + oop_size;
94 }
95
96 // Last object. Need to do dead-obj filtering here too.
97 if (!g1h->is_obj_dead(oop(cur), _hr)) {
98 oop(cur)->oop_iterate(_rs_scan, mr);
99 }
100 }
101 }
102
103 size_t HeapRegion::max_region_size() {
104 return HeapRegionBounds::max_size();
105 }
106
107 size_t HeapRegion::min_region_size_in_words() {
108 return HeapRegionBounds::min_size() >> LogHeapWordSize;
109 }
110
111 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
112 size_t region_size = G1HeapRegionSize;
113 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
114 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
115 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(),
116 HeapRegionBounds::min_size());
117 }
118
119 int region_size_log = log2_long((jlong) region_size);
120 // Recalculate the region size to make sure it's a power of
121 // 2. This means that region_size is the largest power of 2 that's
122 // <= what we've calculated so far.
123 region_size = ((size_t)1 << region_size_log);
124
125 // Now make sure that we don't go over or under our limits.
126 if (region_size < HeapRegionBounds::min_size()) {
127 region_size = HeapRegionBounds::min_size();
128 } else if (region_size > HeapRegionBounds::max_size()) {
129 region_size = HeapRegionBounds::max_size();
130 }
131
132 // And recalculate the log.
133 region_size_log = log2_long((jlong) region_size);
134
135 // Now, set up the globals.
136 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
137 LogOfHRGrainBytes = region_size_log;
138
139 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
140 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
141
142 guarantee(GrainBytes == 0, "we should only set it once");
143 // The cast to int is safe, given that we've bounded region_size by
144 // MIN_REGION_SIZE and MAX_REGION_SIZE.
145 GrainBytes = region_size;
146
147 guarantee(GrainWords == 0, "we should only set it once");
148 GrainWords = GrainBytes >> LogHeapWordSize;
149 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
150
151 guarantee(CardsPerRegion == 0, "we should only set it once");
152 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
153 }
154
155 void HeapRegion::reset_after_compaction() {
156 G1OffsetTableContigSpace::reset_after_compaction();
157 // After a compaction the mark bitmap is invalid, so we must
158 // treat all objects as being inside the unmarked area.
159 zero_marked_bytes();
160 init_top_at_mark_start();
161 }
162
163 void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
164 assert(_humongous_start_region == NULL,
165 "we should have already filtered out humongous regions");
166 assert(_end == orig_end(),
167 "we should have already filtered out humongous regions");
168 assert(!in_collection_set(),
169 "Should not clear heap region %u in the collection set", hrm_index());
170
171 set_allocation_context(AllocationContext::system());
172 set_young_index_in_cset(-1);
173 uninstall_surv_rate_group();
174 set_free();
175 reset_pre_dummy_top();
176
177 if (!par) {
178 // If this is parallel, this will be done later.
179 HeapRegionRemSet* hrrs = rem_set();
180 if (locked) {
181 hrrs->clear_locked();
182 } else {
183 hrrs->clear();
184 }
185 }
186 zero_marked_bytes();
187
188 _offsets.resize(HeapRegion::GrainWords);
189 init_top_at_mark_start();
190 if (clear_space) clear(SpaceDecorator::Mangle);
191 }
192
193 void HeapRegion::par_clear() {
194 assert(used() == 0, "the region should have been already cleared");
195 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
196 HeapRegionRemSet* hrrs = rem_set();
197 hrrs->clear();
198 CardTableModRefBS* ct_bs =
199 barrier_set_cast<CardTableModRefBS>(G1CollectedHeap::heap()->barrier_set());
200 ct_bs->clear(MemRegion(bottom(), end()));
201 }
202
203 void HeapRegion::calc_gc_efficiency() {
204 // GC efficiency is the ratio of how much space would be
205 // reclaimed over how long we predict it would take to reclaim it.
206 G1CollectedHeap* g1h = G1CollectedHeap::heap();
207 G1CollectorPolicy* g1p = g1h->g1_policy();
208
209 // Retrieve a prediction of the elapsed time for this region for
210 // a mixed gc because the region will only be evacuated during a
211 // mixed gc.
212 double region_elapsed_time_ms =
213 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
214 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
215 }
216
217 void HeapRegion::set_starts_humongous(HeapWord* new_top, HeapWord* new_end) {
218 assert(!is_humongous(), "sanity / pre-condition");
219 assert(end() == orig_end(),
220 "Should be normal before the humongous object allocation");
221 assert(top() == bottom(), "should be empty");
222 assert(bottom() <= new_top && new_top <= new_end, "pre-condition");
223
224 _type.set_starts_humongous();
225 _humongous_start_region = this;
226
227 set_end(new_end);
228 _offsets.set_for_starts_humongous(new_top);
229 }
230
231 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) {
232 assert(!is_humongous(), "sanity / pre-condition");
233 assert(end() == orig_end(),
234 "Should be normal before the humongous object allocation");
235 assert(top() == bottom(), "should be empty");
236 assert(first_hr->is_starts_humongous(), "pre-condition");
237
238 _type.set_continues_humongous();
239 _humongous_start_region = first_hr;
240 }
241
242 void HeapRegion::clear_humongous() {
243 assert(is_humongous(), "pre-condition");
244
245 if (is_starts_humongous()) {
246 assert(top() <= end(), "pre-condition");
247 set_end(orig_end());
248 if (top() > end()) {
249 // at least one "continues humongous" region after it
250 set_top(end());
251 }
252 } else {
253 // continues humongous
254 assert(end() == orig_end(), "sanity");
255 }
256
257 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
258 _humongous_start_region = NULL;
259 }
260
261 HeapRegion::HeapRegion(uint hrm_index,
262 G1BlockOffsetSharedArray* sharedOffsetArray,
263 MemRegion mr) :
264 G1OffsetTableContigSpace(sharedOffsetArray, mr),
265 _hrm_index(hrm_index),
266 _allocation_context(AllocationContext::system()),
267 _humongous_start_region(NULL),
268 _next_in_special_set(NULL),
269 _evacuation_failed(false),
270 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
271 _next_young_region(NULL),
272 _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL),
273 #ifdef ASSERT
274 _containing_set(NULL),
275 #endif // ASSERT
276 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
277 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
278 _predicted_bytes_to_copy(0)
279 {
280 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
281 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
282
283 initialize(mr);
284 }
285
286 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
287 assert(_rem_set->is_empty(), "Remembered set must be empty");
288
289 G1OffsetTableContigSpace::initialize(mr, clear_space, mangle_space);
290
291 hr_clear(false /*par*/, false /*clear_space*/);
292 set_top(bottom());
293 record_timestamp();
294
295 assert(mr.end() == orig_end(),
296 "Given region end address " PTR_FORMAT " should match exactly "
297 "bottom plus one region size, i.e. " PTR_FORMAT,
298 p2i(mr.end()), p2i(orig_end()));
299 }
300
301 CompactibleSpace* HeapRegion::next_compaction_space() const {
302 return G1CollectedHeap::heap()->next_compaction_region(this);
303 }
304
305 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
306 bool during_conc_mark) {
307 // We always recreate the prev marking info and we'll explicitly
308 // mark all objects we find to be self-forwarded on the prev
309 // bitmap. So all objects need to be below PTAMS.
310 _prev_marked_bytes = 0;
311
312 if (during_initial_mark) {
313 // During initial-mark, we'll also explicitly mark all objects
314 // we find to be self-forwarded on the next bitmap. So all
315 // objects need to be below NTAMS.
316 _next_top_at_mark_start = top();
317 _next_marked_bytes = 0;
318 } else if (during_conc_mark) {
319 // During concurrent mark, all objects in the CSet (including
320 // the ones we find to be self-forwarded) are implicitly live.
321 // So all objects need to be above NTAMS.
322 _next_top_at_mark_start = bottom();
323 _next_marked_bytes = 0;
324 }
325 }
326
327 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
328 bool during_conc_mark,
329 size_t marked_bytes) {
330 assert(marked_bytes <= used(),
331 "marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used());
332 _prev_top_at_mark_start = top();
333 _prev_marked_bytes = marked_bytes;
334 }
335
336 HeapWord*
337 HeapRegion::object_iterate_mem_careful(MemRegion mr,
338 ObjectClosure* cl) {
339 G1CollectedHeap* g1h = G1CollectedHeap::heap();
340 // We used to use "block_start_careful" here. But we're actually happy
341 // to update the BOT while we do this...
342 HeapWord* cur = block_start(mr.start());
343 mr = mr.intersection(used_region());
344 if (mr.is_empty()) return NULL;
345 // Otherwise, find the obj that extends onto mr.start().
346
347 assert(cur <= mr.start()
348 && (oop(cur)->klass_or_null() == NULL ||
349 cur + oop(cur)->size() > mr.start()),
350 "postcondition of block_start");
351 oop obj;
352 while (cur < mr.end()) {
353 obj = oop(cur);
354 if (obj->klass_or_null() == NULL) {
355 // Ran into an unparseable point.
356 return cur;
357 } else if (!g1h->is_obj_dead(obj)) {
358 cl->do_object(obj);
359 }
360 cur += block_size(cur);
361 }
362 return NULL;
363 }
364
365 HeapWord*
366 HeapRegion::
367 oops_on_card_seq_iterate_careful(MemRegion mr,
368 FilterOutOfRegionClosure* cl,
369 bool filter_young,
370 jbyte* card_ptr) {
371 // Currently, we should only have to clean the card if filter_young
372 // is true and vice versa.
373 if (filter_young) {
374 assert(card_ptr != NULL, "pre-condition");
375 } else {
376 assert(card_ptr == NULL, "pre-condition");
377 }
378 G1CollectedHeap* g1h = G1CollectedHeap::heap();
379
380 // If we're within a stop-world GC, then we might look at a card in a
381 // GC alloc region that extends onto a GC LAB, which may not be
382 // parseable. Stop such at the "scan_top" of the region.
383 if (g1h->is_gc_active()) {
384 mr = mr.intersection(MemRegion(bottom(), scan_top()));
385 } else {
386 mr = mr.intersection(used_region());
387 }
388 if (mr.is_empty()) return NULL;
389 // Otherwise, find the obj that extends onto mr.start().
390
391 // The intersection of the incoming mr (for the card) and the
392 // allocated part of the region is non-empty. This implies that
393 // we have actually allocated into this region. The code in
394 // G1CollectedHeap.cpp that allocates a new region sets the
395 // is_young tag on the region before allocating. Thus we
396 // safely know if this region is young.
397 if (is_young() && filter_young) {
398 return NULL;
399 }
400
401 assert(!is_young(), "check value of filter_young");
402
403 // We can only clean the card here, after we make the decision that
404 // the card is not young. And we only clean the card if we have been
405 // asked to (i.e., card_ptr != NULL).
406 if (card_ptr != NULL) {
407 *card_ptr = CardTableModRefBS::clean_card_val();
408 // We must complete this write before we do any of the reads below.
409 OrderAccess::storeload();
410 }
411
412 // Cache the boundaries of the memory region in some const locals
413 HeapWord* const start = mr.start();
414 HeapWord* const end = mr.end();
415
416 // We used to use "block_start_careful" here. But we're actually happy
417 // to update the BOT while we do this...
418 HeapWord* cur = block_start(start);
419 assert(cur <= start, "Postcondition");
420
421 oop obj;
422
423 HeapWord* next = cur;
424 do {
425 cur = next;
426 obj = oop(cur);
427 if (obj->klass_or_null() == NULL) {
428 // Ran into an unparseable point.
429 return cur;
430 }
431 // Otherwise...
432 next = cur + block_size(cur);
433 } while (next <= start);
434
435 // If we finish the above loop...We have a parseable object that
436 // begins on or before the start of the memory region, and ends
437 // inside or spans the entire region.
438 assert(cur <= start, "Loop postcondition");
439 assert(obj->klass_or_null() != NULL, "Loop postcondition");
440
441 do {
442 obj = oop(cur);
443 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant");
444 if (obj->klass_or_null() == NULL) {
445 // Ran into an unparseable point.
446 return cur;
447 }
448
449 // Advance the current pointer. "obj" still points to the object to iterate.
450 cur = cur + block_size(cur);
451
452 if (!g1h->is_obj_dead(obj)) {
453 // Non-objArrays are sometimes marked imprecise at the object start. We
454 // always need to iterate over them in full.
455 // We only iterate over object arrays in full if they are completely contained
456 // in the memory region.
457 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) {
458 obj->oop_iterate(cl);
459 } else {
460 obj->oop_iterate(cl, mr);
461 }
462 }
463 } while (cur < end);
464
465 return NULL;
466 }
467
468 // Code roots support
469
470 void HeapRegion::add_strong_code_root(nmethod* nm) {
471 HeapRegionRemSet* hrrs = rem_set();
472 hrrs->add_strong_code_root(nm);
473 }
474
475 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
476 assert_locked_or_safepoint(CodeCache_lock);
477 HeapRegionRemSet* hrrs = rem_set();
478 hrrs->add_strong_code_root_locked(nm);
479 }
480
481 void HeapRegion::remove_strong_code_root(nmethod* nm) {
482 HeapRegionRemSet* hrrs = rem_set();
483 hrrs->remove_strong_code_root(nm);
484 }
485
486 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
487 HeapRegionRemSet* hrrs = rem_set();
488 hrrs->strong_code_roots_do(blk);
489 }
490
491 class VerifyStrongCodeRootOopClosure: public OopClosure {
492 const HeapRegion* _hr;
493 nmethod* _nm;
494 bool _failures;
495 bool _has_oops_in_region;
496
497 template <class T> void do_oop_work(T* p) {
498 T heap_oop = oopDesc::load_heap_oop(p);
499 if (!oopDesc::is_null(heap_oop)) {
500 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
501
502 // Note: not all the oops embedded in the nmethod are in the
503 // current region. We only look at those which are.
504 if (_hr->is_in(obj)) {
505 // Object is in the region. Check that its less than top
506 if (_hr->top() <= (HeapWord*)obj) {
507 // Object is above top
508 log_info(gc, verify)("Object " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ") is above top " PTR_FORMAT,
509 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top()));
510 _failures = true;
511 return;
512 }
513 // Nmethod has at least one oop in the current region
514 _has_oops_in_region = true;
515 }
516 }
517 }
518
519 public:
520 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
521 _hr(hr), _failures(false), _has_oops_in_region(false) {}
522
523 void do_oop(narrowOop* p) { do_oop_work(p); }
524 void do_oop(oop* p) { do_oop_work(p); }
525
526 bool failures() { return _failures; }
527 bool has_oops_in_region() { return _has_oops_in_region; }
528 };
529
530 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
531 const HeapRegion* _hr;
532 bool _failures;
533 public:
534 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
535 _hr(hr), _failures(false) {}
536
537 void do_code_blob(CodeBlob* cb) {
538 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
539 if (nm != NULL) {
540 // Verify that the nemthod is live
541 if (!nm->is_alive()) {
542 log_info(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " PTR_FORMAT " in its strong code roots",
543 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
544 _failures = true;
545 } else {
546 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
547 nm->oops_do(&oop_cl);
548 if (!oop_cl.has_oops_in_region()) {
549 log_info(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " PTR_FORMAT " in its strong code roots with no pointers into region",
550 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
551 _failures = true;
552 } else if (oop_cl.failures()) {
553 log_info(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has other failures for nmethod " PTR_FORMAT,
554 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
555 _failures = true;
556 }
557 }
558 }
559 }
560
561 bool failures() { return _failures; }
562 };
563
564 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
565 if (!G1VerifyHeapRegionCodeRoots) {
566 // We're not verifying code roots.
567 return;
568 }
569 if (vo == VerifyOption_G1UseMarkWord) {
570 // Marking verification during a full GC is performed after class
571 // unloading, code cache unloading, etc so the strong code roots
572 // attached to each heap region are in an inconsistent state. They won't
573 // be consistent until the strong code roots are rebuilt after the
574 // actual GC. Skip verifying the strong code roots in this particular
575 // time.
576 assert(VerifyDuringGC, "only way to get here");
577 return;
578 }
579
580 HeapRegionRemSet* hrrs = rem_set();
581 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
582
583 // if this region is empty then there should be no entries
584 // on its strong code root list
585 if (is_empty()) {
586 if (strong_code_roots_length > 0) {
587 log_info(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] is empty but has " SIZE_FORMAT " code root entries",
588 p2i(bottom()), p2i(end()), strong_code_roots_length);
589 *failures = true;
590 }
591 return;
592 }
593
594 if (is_continues_humongous()) {
595 if (strong_code_roots_length > 0) {
596 log_info(gc, verify)("region " HR_FORMAT " is a continuation of a humongous region but has " SIZE_FORMAT " code root entries",
597 HR_FORMAT_PARAMS(this), strong_code_roots_length);
598 *failures = true;
599 }
600 return;
601 }
602
603 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
604 strong_code_roots_do(&cb_cl);
605
606 if (cb_cl.failures()) {
607 *failures = true;
608 }
609 }
610
611 void HeapRegion::print() const { print_on(tty); }
612 void HeapRegion::print_on(outputStream* st) const {
613 st->print("AC%4u", allocation_context());
614
615 st->print(" %2s", get_short_type_str());
616 if (in_collection_set())
617 st->print(" CS");
618 else
619 st->print(" ");
620 st->print(" TS %5d", _gc_time_stamp);
621 st->print(" PTAMS " PTR_FORMAT " NTAMS " PTR_FORMAT,
622 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start()));
623 G1OffsetTableContigSpace::print_on(st);
624 }
625
626 class VerifyLiveClosure: public OopClosure {
627 private:
628 G1CollectedHeap* _g1h;
629 CardTableModRefBS* _bs;
630 oop _containing_obj;
631 bool _failures;
632 int _n_failures;
633 VerifyOption _vo;
634 public:
635 // _vo == UsePrevMarking -> use "prev" marking information,
636 // _vo == UseNextMarking -> use "next" marking information,
637 // _vo == UseMarkWord -> use mark word from object header.
638 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) :
639 _g1h(g1h), _bs(barrier_set_cast<CardTableModRefBS>(g1h->barrier_set())),
640 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo)
641 { }
642
643 void set_containing_obj(oop obj) {
644 _containing_obj = obj;
645 }
646
647 bool failures() { return _failures; }
648 int n_failures() { return _n_failures; }
649
650 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
651 virtual void do_oop( oop* p) { do_oop_work(p); }
652
653 void print_object(outputStream* out, oop obj) {
654 #ifdef PRODUCT
655 Klass* k = obj->klass();
656 const char* class_name = k->external_name();
657 out->print_cr("class name %s", class_name);
658 #else // PRODUCT
659 obj->print_on(out);
660 #endif // PRODUCT
661 }
662
663 template <class T>
664 void do_oop_work(T* p) {
665 assert(_containing_obj != NULL, "Precondition");
666 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
667 "Precondition");
668 T heap_oop = oopDesc::load_heap_oop(p);
669 LogHandle(gc, verify) log;
670 if (!oopDesc::is_null(heap_oop)) {
671 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
672 bool failed = false;
673 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
674 MutexLockerEx x(ParGCRareEvent_lock,
675 Mutex::_no_safepoint_check_flag);
676
677 if (!_failures) {
678 log.info("----------");
679 }
680 ResourceMark rm;
681 if (!_g1h->is_in_closed_subset(obj)) {
682 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
683 log.info("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
684 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
685 print_object(log.info_stream(), _containing_obj);
686 log.info("points to obj " PTR_FORMAT " not in the heap", p2i(obj));
687 } else {
688 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
689 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
690 log.info("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
691 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
692 print_object(log.info_stream(), _containing_obj);
693 log.info("points to dead obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
694 p2i(obj), p2i(to->bottom()), p2i(to->end()));
695 print_object(log.info_stream(), obj);
696 }
697 log.info("----------");
698 _failures = true;
699 failed = true;
700 _n_failures++;
701 }
702
703 if (!_g1h->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) {
704 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
705 HeapRegion* to = _g1h->heap_region_containing(obj);
706 if (from != NULL && to != NULL &&
707 from != to &&
708 !to->is_pinned()) {
709 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
710 jbyte cv_field = *_bs->byte_for_const(p);
711 const jbyte dirty = CardTableModRefBS::dirty_card_val();
712
713 bool is_bad = !(from->is_young()
714 || to->rem_set()->contains_reference(p)
715 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
716 (_containing_obj->is_objArray() ?
717 cv_field == dirty
718 : cv_obj == dirty || cv_field == dirty));
719 if (is_bad) {
720 MutexLockerEx x(ParGCRareEvent_lock,
721 Mutex::_no_safepoint_check_flag);
722
723 if (!_failures) {
724 log.info("----------");
725 }
726 log.info("Missing rem set entry:");
727 log.info("Field " PTR_FORMAT " of obj " PTR_FORMAT ", in region " HR_FORMAT,
728 p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
729 ResourceMark rm;
730 _containing_obj->print_on(log.info_stream());
731 log.info("points to obj " PTR_FORMAT " in region " HR_FORMAT, p2i(obj), HR_FORMAT_PARAMS(to));
732 obj->print_on(log.info_stream());
733 log.info("Obj head CTE = %d, field CTE = %d.", cv_obj, cv_field);
734 log.info("----------");
735 _failures = true;
736 if (!failed) _n_failures++;
737 }
738 }
739 }
740 }
741 }
742 };
743
744 // This really ought to be commoned up into OffsetTableContigSpace somehow.
745 // We would need a mechanism to make that code skip dead objects.
746
747 void HeapRegion::verify(VerifyOption vo,
748 bool* failures) const {
749 G1CollectedHeap* g1 = G1CollectedHeap::heap();
750 *failures = false;
751 HeapWord* p = bottom();
752 HeapWord* prev_p = NULL;
753 VerifyLiveClosure vl_cl(g1, vo);
754 bool is_region_humongous = is_humongous();
755 size_t object_num = 0;
756 while (p < top()) {
757 oop obj = oop(p);
758 size_t obj_size = block_size(p);
759 object_num += 1;
760
761 if (is_region_humongous != g1->is_humongous(obj_size) &&
762 !g1->is_obj_dead(obj, this)) { // Dead objects may have bigger block_size since they span several objects.
763 log_info(gc, verify)("obj " PTR_FORMAT " is of %shumongous size ("
764 SIZE_FORMAT " words) in a %shumongous region",
765 p2i(p), g1->is_humongous(obj_size) ? "" : "non-",
766 obj_size, is_region_humongous ? "" : "non-");
767 *failures = true;
768 return;
769 }
770
771 if (!g1->is_obj_dead_cond(obj, this, vo)) {
772 if (obj->is_oop()) {
773 Klass* klass = obj->klass();
774 bool is_metaspace_object = Metaspace::contains(klass) ||
775 (vo == VerifyOption_G1UsePrevMarking &&
776 ClassLoaderDataGraph::unload_list_contains(klass));
777 if (!is_metaspace_object) {
778 log_info(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
779 "not metadata", p2i(klass), p2i(obj));
780 *failures = true;
781 return;
782 } else if (!klass->is_klass()) {
783 log_info(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
784 "not a klass", p2i(klass), p2i(obj));
785 *failures = true;
786 return;
787 } else {
788 vl_cl.set_containing_obj(obj);
789 obj->oop_iterate_no_header(&vl_cl);
790 if (vl_cl.failures()) {
791 *failures = true;
792 }
793 if (G1MaxVerifyFailures >= 0 &&
794 vl_cl.n_failures() >= G1MaxVerifyFailures) {
795 return;
796 }
797 }
798 } else {
799 log_info(gc, verify)(PTR_FORMAT " no an oop", p2i(obj));
800 *failures = true;
801 return;
802 }
803 }
804 prev_p = p;
805 p += obj_size;
806 }
807
808 if (!is_young() && !is_empty()) {
809 _offsets.verify();
810 }
811
812 if (p != top()) {
813 log_info(gc, verify)("end of last object " PTR_FORMAT " "
814 "does not match top " PTR_FORMAT, p2i(p), p2i(top()));
815 *failures = true;
816 return;
817 }
818
819 HeapWord* the_end = end();
820 assert(p == top(), "it should still hold");
821 // Do some extra BOT consistency checking for addresses in the
822 // range [top, end). BOT look-ups in this range should yield
823 // top. No point in doing that if top == end (there's nothing there).
824 if (p < the_end) {
825 // Look up top
826 HeapWord* addr_1 = p;
827 HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
828 if (b_start_1 != p) {
829 log_info(gc, verify)("BOT look up for top: " PTR_FORMAT " "
830 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
831 p2i(addr_1), p2i(b_start_1), p2i(p));
832 *failures = true;
833 return;
834 }
835
836 // Look up top + 1
837 HeapWord* addr_2 = p + 1;
838 if (addr_2 < the_end) {
839 HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
840 if (b_start_2 != p) {
841 log_info(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " "
842 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
843 p2i(addr_2), p2i(b_start_2), p2i(p));
844 *failures = true;
845 return;
846 }
847 }
848
849 // Look up an address between top and end
850 size_t diff = pointer_delta(the_end, p) / 2;
851 HeapWord* addr_3 = p + diff;
852 if (addr_3 < the_end) {
853 HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
854 if (b_start_3 != p) {
855 log_info(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " "
856 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
857 p2i(addr_3), p2i(b_start_3), p2i(p));
858 *failures = true;
859 return;
860 }
861 }
862
863 // Look up end - 1
864 HeapWord* addr_4 = the_end - 1;
865 HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
866 if (b_start_4 != p) {
867 log_info(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " "
868 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
869 p2i(addr_4), p2i(b_start_4), p2i(p));
870 *failures = true;
871 return;
872 }
873 }
874
875 if (is_region_humongous && object_num > 1) {
876 log_info(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] is humongous "
877 "but has " SIZE_FORMAT ", objects",
878 p2i(bottom()), p2i(end()), object_num);
879 *failures = true;
880 return;
881 }
882
883 verify_strong_code_roots(vo, failures);
884 }
885
886 void HeapRegion::verify() const {
887 bool dummy = false;
888 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
889 }
890
891 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
892 scan_and_forward(this, cp);
893 }
894
895 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
896 // away eventually.
897
898 void G1OffsetTableContigSpace::clear(bool mangle_space) {
899 set_top(bottom());
900 _scan_top = bottom();
901 CompactibleSpace::clear(mangle_space);
902 reset_bot();
903 }
904
905 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
906 Space::set_bottom(new_bottom);
907 _offsets.set_bottom(new_bottom);
908 }
909
910 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
911 Space::set_end(new_end);
912 _offsets.resize(new_end - bottom());
913 }
914
915 #ifndef PRODUCT
916 void G1OffsetTableContigSpace::mangle_unused_area() {
917 mangle_unused_area_complete();
918 }
919
920 void G1OffsetTableContigSpace::mangle_unused_area_complete() {
921 SpaceMangler::mangle_region(MemRegion(top(), end()));
922 }
923 #endif
924
925 void G1OffsetTableContigSpace::print() const {
926 print_short();
927 tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
928 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
929 p2i(bottom()), p2i(top()), p2i(_offsets.threshold()), p2i(end()));
930 }
931
932 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
933 return _offsets.initialize_threshold();
934 }
935
936 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
937 HeapWord* end) {
938 _offsets.alloc_block(start, end);
939 return _offsets.threshold();
940 }
941
942 HeapWord* G1OffsetTableContigSpace::scan_top() const {
943 G1CollectedHeap* g1h = G1CollectedHeap::heap();
944 HeapWord* local_top = top();
945 OrderAccess::loadload();
946 const unsigned local_time_stamp = _gc_time_stamp;
947 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
948 if (local_time_stamp < g1h->get_gc_time_stamp()) {
949 return local_top;
950 } else {
951 return _scan_top;
952 }
953 }
954
955 void G1OffsetTableContigSpace::record_timestamp() {
956 G1CollectedHeap* g1h = G1CollectedHeap::heap();
957 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
958
959 if (_gc_time_stamp < curr_gc_time_stamp) {
960 // Setting the time stamp here tells concurrent readers to look at
961 // scan_top to know the maximum allowed address to look at.
962
963 // scan_top should be bottom for all regions except for the
964 // retained old alloc region which should have scan_top == top
965 HeapWord* st = _scan_top;
966 guarantee(st == _bottom || st == _top, "invariant");
967
968 _gc_time_stamp = curr_gc_time_stamp;
969 }
970 }
971
972 void G1OffsetTableContigSpace::record_retained_region() {
973 // scan_top is the maximum address where it's safe for the next gc to
974 // scan this region.
975 _scan_top = top();
976 }
977
978 void G1OffsetTableContigSpace::safe_object_iterate(ObjectClosure* blk) {
979 object_iterate(blk);
980 }
981
982 void G1OffsetTableContigSpace::object_iterate(ObjectClosure* blk) {
983 HeapWord* p = bottom();
984 while (p < top()) {
985 if (block_is_obj(p)) {
986 blk->do_object(oop(p));
987 }
988 p += block_size(p);
989 }
990 }
991
992 G1OffsetTableContigSpace::
993 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
994 MemRegion mr) :
995 _offsets(sharedOffsetArray, mr),
996 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
997 _gc_time_stamp(0)
998 {
999 _offsets.set_space(this);
1000 }
1001
1002 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
1003 CompactibleSpace::initialize(mr, clear_space, mangle_space);
1004 _top = bottom();
1005 _scan_top = bottom();
1006 set_saved_mark_word(NULL);
1007 reset_bot();
1008 }
1009