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