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