1 /*
2 * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "code/nmethod.hpp"
27 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
28 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
29 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
30 #include "gc_implementation/g1/heapRegion.inline.hpp"
31 #include "gc_implementation/g1/heapRegionBounds.inline.hpp"
32 #include "gc_implementation/g1/heapRegionRemSet.hpp"
33 #include "gc_implementation/g1/heapRegionManager.inline.hpp"
34 #include "gc_implementation/shared/liveRange.hpp"
35 #include "memory/genOopClosures.inline.hpp"
36 #include "memory/iterator.hpp"
37 #include "memory/space.inline.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "runtime/atomic.inline.hpp"
40 #include "runtime/orderAccess.inline.hpp"
41
42 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
43
44 int HeapRegion::LogOfHRGrainBytes = 0;
45 int HeapRegion::LogOfHRGrainWords = 0;
46 size_t HeapRegion::GrainBytes = 0;
47 size_t HeapRegion::GrainWords = 0;
48 size_t HeapRegion::CardsPerRegion = 0;
49
50 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
51 HeapRegion* hr,
52 G1ParPushHeapRSClosure* cl,
53 CardTableModRefBS::PrecisionStyle precision) :
54 DirtyCardToOopClosure(hr, cl, precision, NULL),
55 _hr(hr), _rs_scan(cl), _g1(g1) { }
56
57 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
58 OopClosure* oc) :
59 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
60
61 void HeapRegionDCTOC::walk_mem_region(MemRegion mr,
62 HeapWord* bottom,
63 HeapWord* top) {
64 G1CollectedHeap* g1h = _g1;
65 size_t oop_size;
66 HeapWord* cur = bottom;
67
68 // Start filtering what we add to the remembered set. If the object is
69 // not considered dead, either because it is marked (in the mark bitmap)
70 // or it was allocated after marking finished, then we add it. Otherwise
71 // we can safely ignore the object.
72 if (!g1h->is_obj_dead(oop(cur), _hr)) {
73 oop_size = oop(cur)->oop_iterate(_rs_scan, mr);
74 } else {
75 oop_size = _hr->block_size(cur);
76 }
77
78 cur += oop_size;
79
80 if (cur < top) {
81 oop cur_oop = oop(cur);
82 oop_size = _hr->block_size(cur);
83 HeapWord* next_obj = cur + oop_size;
84 while (next_obj < top) {
85 // Keep filtering the remembered set.
86 if (!g1h->is_obj_dead(cur_oop, _hr)) {
87 // Bottom lies entirely below top, so we can call the
88 // non-memRegion version of oop_iterate below.
89 cur_oop->oop_iterate(_rs_scan);
90 }
91 cur = next_obj;
92 cur_oop = oop(cur);
93 oop_size = _hr->block_size(cur);
94 next_obj = cur + oop_size;
95 }
96
97 // Last object. Need to do dead-obj filtering here too.
98 if (!g1h->is_obj_dead(oop(cur), _hr)) {
99 oop(cur)->oop_iterate(_rs_scan, mr);
100 }
101 }
102 }
103
104 size_t HeapRegion::max_region_size() {
105 return HeapRegionBounds::max_size();
106 }
107
108 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
109 uintx region_size = G1HeapRegionSize;
110 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
111 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
112 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(),
113 (uintx) HeapRegionBounds::min_size());
114 }
115
116 int region_size_log = log2_long((jlong) region_size);
117 // Recalculate the region size to make sure it's a power of
118 // 2. This means that region_size is the largest power of 2 that's
119 // <= what we've calculated so far.
120 region_size = ((uintx)1 << region_size_log);
121
122 // Now make sure that we don't go over or under our limits.
123 if (region_size < HeapRegionBounds::min_size()) {
124 region_size = HeapRegionBounds::min_size();
125 } else if (region_size > HeapRegionBounds::max_size()) {
126 region_size = HeapRegionBounds::max_size();
127 }
128
129 // And recalculate the log.
130 region_size_log = log2_long((jlong) region_size);
131
132 // Now, set up the globals.
133 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
134 LogOfHRGrainBytes = region_size_log;
135
136 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
137 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
138
139 guarantee(GrainBytes == 0, "we should only set it once");
140 // The cast to int is safe, given that we've bounded region_size by
141 // MIN_REGION_SIZE and MAX_REGION_SIZE.
142 GrainBytes = (size_t)region_size;
143
144 guarantee(GrainWords == 0, "we should only set it once");
145 GrainWords = GrainBytes >> LogHeapWordSize;
146 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
147
148 guarantee(CardsPerRegion == 0, "we should only set it once");
149 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
150 }
151
152 void HeapRegion::reset_after_compaction() {
153 G1OffsetTableContigSpace::reset_after_compaction();
154 // After a compaction the mark bitmap is invalid, so we must
155 // treat all objects as being inside the unmarked area.
156 zero_marked_bytes();
157 init_top_at_mark_start();
158 }
159
160 void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
161 assert(_humongous_start_region == NULL,
162 "we should have already filtered out humongous regions");
163 assert(_end == orig_end(),
164 "we should have already filtered out humongous regions");
165 assert(!_in_collection_set,
166 err_msg("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 (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* new_top, HeapWord* new_end) {
215 assert(!is_humongous(), "sanity / pre-condition");
216 assert(end() == orig_end(),
217 "Should be normal before the humongous object allocation");
218 assert(top() == bottom(), "should be empty");
219 assert(bottom() <= new_top && new_top <= new_end, "pre-condition");
220
221 _type.set_starts_humongous();
222 _humongous_start_region = this;
223
224 set_end(new_end);
225 _offsets.set_for_starts_humongous(new_top);
226 }
227
228 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) {
229 assert(!is_humongous(), "sanity / pre-condition");
230 assert(end() == orig_end(),
231 "Should be normal before the humongous object allocation");
232 assert(top() == bottom(), "should be empty");
233 assert(first_hr->is_starts_humongous(), "pre-condition");
234
235 _type.set_continues_humongous();
236 _humongous_start_region = first_hr;
237 }
238
239 void HeapRegion::clear_humongous() {
240 assert(is_humongous(), "pre-condition");
241
242 if (is_starts_humongous()) {
243 assert(top() <= end(), "pre-condition");
244 set_end(orig_end());
245 if (top() > end()) {
246 // at least one "continues humongous" region after it
247 set_top(end());
248 }
249 } else {
250 // continues humongous
251 assert(end() == orig_end(), "sanity");
252 }
253
254 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
255 _humongous_start_region = NULL;
256 }
257
258 HeapRegion::HeapRegion(uint hrm_index,
259 G1BlockOffsetSharedArray* sharedOffsetArray,
260 MemRegion mr) :
261 G1OffsetTableContigSpace(sharedOffsetArray, mr),
262 _hrm_index(hrm_index),
263 _allocation_context(AllocationContext::system()),
264 _humongous_start_region(NULL),
265 _in_collection_set(false),
266 _next_in_special_set(NULL),
267 _evacuation_failed(false),
268 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
269 _next_young_region(NULL),
270 _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL),
271 #ifdef ASSERT
272 _containing_set(NULL),
273 #endif // ASSERT
274 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
275 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
276 _predicted_bytes_to_copy(0)
277 {
278 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
279 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
280
281 initialize(mr);
282 }
283
284 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
285 assert(_rem_set->is_empty(), "Remembered set must be empty");
286
287 G1OffsetTableContigSpace::initialize(mr, clear_space, mangle_space);
288
289 hr_clear(false /*par*/, false /*clear_space*/);
290 set_top(bottom());
291 record_timestamp();
292
293 assert(mr.end() == orig_end(),
294 err_msg("Given region end address " PTR_FORMAT " should match exactly "
295 "bottom plus one region size, i.e. " PTR_FORMAT,
296 p2i(mr.end()), p2i(orig_end())));
297 }
298
299 CompactibleSpace* HeapRegion::next_compaction_space() const {
300 return G1CollectedHeap::heap()->next_compaction_region(this);
301 }
302
303 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
304 bool during_conc_mark) {
305 // We always recreate the prev marking info and we'll explicitly
306 // mark all objects we find to be self-forwarded on the prev
307 // bitmap. So all objects need to be below PTAMS.
308 _prev_marked_bytes = 0;
309
310 if (during_initial_mark) {
311 // During initial-mark, we'll also explicitly mark all objects
312 // we find to be self-forwarded on the next bitmap. So all
313 // objects need to be below NTAMS.
314 _next_top_at_mark_start = top();
315 _next_marked_bytes = 0;
316 } else if (during_conc_mark) {
317 // During concurrent mark, all objects in the CSet (including
318 // the ones we find to be self-forwarded) are implicitly live.
319 // So all objects need to be above NTAMS.
320 _next_top_at_mark_start = bottom();
321 _next_marked_bytes = 0;
322 }
323 }
324
325 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
326 bool during_conc_mark,
327 size_t marked_bytes) {
328 assert(marked_bytes <= used(),
329 err_msg("marked: "SIZE_FORMAT" used: "SIZE_FORMAT, marked_bytes, used()));
330 _prev_top_at_mark_start = top();
331 _prev_marked_bytes = marked_bytes;
332 }
333
334 HeapWord*
335 HeapRegion::object_iterate_mem_careful(MemRegion mr,
336 ObjectClosure* cl) {
337 G1CollectedHeap* g1h = G1CollectedHeap::heap();
338 // We used to use "block_start_careful" here. But we're actually happy
339 // to update the BOT while we do this...
340 HeapWord* cur = block_start(mr.start());
341 mr = mr.intersection(used_region());
342 if (mr.is_empty()) return NULL;
343 // Otherwise, find the obj that extends onto mr.start().
344
345 assert(cur <= mr.start()
346 && (oop(cur)->klass_or_null() == NULL ||
347 cur + oop(cur)->size() > mr.start()),
348 "postcondition of block_start");
349 oop obj;
350 while (cur < mr.end()) {
351 obj = oop(cur);
352 if (obj->klass_or_null() == NULL) {
353 // Ran into an unparseable point.
354 return cur;
355 } else if (!g1h->is_obj_dead(obj)) {
356 cl->do_object(obj);
357 }
358 cur += block_size(cur);
359 }
360 return NULL;
361 }
362
363 HeapWord*
364 HeapRegion::
365 oops_on_card_seq_iterate_careful(MemRegion mr,
366 FilterOutOfRegionClosure* cl,
367 bool filter_young,
368 jbyte* card_ptr) {
369 // Currently, we should only have to clean the card if filter_young
370 // is true and vice versa.
371 if (filter_young) {
372 assert(card_ptr != NULL, "pre-condition");
373 } else {
374 assert(card_ptr == NULL, "pre-condition");
375 }
376 G1CollectedHeap* g1h = G1CollectedHeap::heap();
377
378 // If we're within a stop-world GC, then we might look at a card in a
379 // GC alloc region that extends onto a GC LAB, which may not be
380 // parseable. Stop such at the "scan_top" of the region.
381 if (g1h->is_gc_active()) {
382 mr = mr.intersection(MemRegion(bottom(), scan_top()));
383 } else {
384 mr = mr.intersection(used_region());
385 }
386 if (mr.is_empty()) return NULL;
387 // Otherwise, find the obj that extends onto mr.start().
388
389 // The intersection of the incoming mr (for the card) and the
390 // allocated part of the region is non-empty. This implies that
391 // we have actually allocated into this region. The code in
392 // G1CollectedHeap.cpp that allocates a new region sets the
393 // is_young tag on the region before allocating. Thus we
394 // safely know if this region is young.
395 if (is_young() && filter_young) {
396 return NULL;
397 }
398
399 assert(!is_young(), "check value of filter_young");
400
401 // We can only clean the card here, after we make the decision that
402 // the card is not young. And we only clean the card if we have been
403 // asked to (i.e., card_ptr != NULL).
404 if (card_ptr != NULL) {
405 *card_ptr = CardTableModRefBS::clean_card_val();
406 // We must complete this write before we do any of the reads below.
407 OrderAccess::storeload();
408 }
409
410 // Cache the boundaries of the memory region in some const locals
411 HeapWord* const start = mr.start();
412 HeapWord* const end = mr.end();
413
414 // We used to use "block_start_careful" here. But we're actually happy
415 // to update the BOT while we do this...
416 HeapWord* cur = block_start(start);
417 assert(cur <= start, "Postcondition");
418
419 oop obj;
420
421 HeapWord* next = cur;
422 while (next <= start) {
423 cur = next;
424 obj = oop(cur);
425 if (obj->klass_or_null() == NULL) {
426 // Ran into an unparseable point.
427 return cur;
428 }
429 // Otherwise...
430 next = cur + block_size(cur);
431 }
432
433 // If we finish the above loop...We have a parseable object that
434 // begins on or before the start of the memory region, and ends
435 // inside or spans the entire region.
436
437 assert(obj == oop(cur), "sanity");
438 assert(cur <= start, "Loop postcondition");
439 assert(obj->klass_or_null() != NULL, "Loop postcondition");
440 assert((cur + block_size(cur)) > start, "Loop postcondition");
441
442 if (!g1h->is_obj_dead(obj)) {
443 obj->oop_iterate(cl, mr);
444 }
445
446 while (cur < end) {
447 obj = oop(cur);
448 if (obj->klass_or_null() == NULL) {
449 // Ran into an unparseable point.
450 return cur;
451 };
452
453 // Otherwise:
454 next = cur + block_size(cur);
455
456 if (!g1h->is_obj_dead(obj)) {
457 if (next < end || !obj->is_objArray()) {
458 // This object either does not span the MemRegion
459 // boundary, or if it does it's not an array.
460 // Apply closure to whole object.
461 obj->oop_iterate(cl);
462 } else {
463 // This obj is an array that spans the boundary.
464 // Stop at the boundary.
465 obj->oop_iterate(cl, mr);
466 }
467 }
468 cur = next;
469 }
470 return NULL;
471 }
472
473 // Code roots support
474
475 void HeapRegion::add_strong_code_root(nmethod* nm) {
476 HeapRegionRemSet* hrrs = rem_set();
477 hrrs->add_strong_code_root(nm);
478 }
479
480 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
481 assert_locked_or_safepoint(CodeCache_lock);
482 HeapRegionRemSet* hrrs = rem_set();
483 hrrs->add_strong_code_root_locked(nm);
484 }
485
486 void HeapRegion::remove_strong_code_root(nmethod* nm) {
487 HeapRegionRemSet* hrrs = rem_set();
488 hrrs->remove_strong_code_root(nm);
489 }
490
491 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
492 HeapRegionRemSet* hrrs = rem_set();
493 hrrs->strong_code_roots_do(blk);
494 }
495
496 class VerifyStrongCodeRootOopClosure: public OopClosure {
497 const HeapRegion* _hr;
498 nmethod* _nm;
499 bool _failures;
500 bool _has_oops_in_region;
501
502 template <class T> void do_oop_work(T* p) {
503 T heap_oop = oopDesc::load_heap_oop(p);
504 if (!oopDesc::is_null(heap_oop)) {
505 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
506
507 // Note: not all the oops embedded in the nmethod are in the
508 // current region. We only look at those which are.
509 if (_hr->is_in(obj)) {
510 // Object is in the region. Check that its less than top
511 if (_hr->top() <= (HeapWord*)obj) {
512 // Object is above top
513 gclog_or_tty->print_cr("Object "PTR_FORMAT" in region "
514 "["PTR_FORMAT", "PTR_FORMAT") is above "
515 "top "PTR_FORMAT,
516 (void *)obj, _hr->bottom(), _hr->end(), _hr->top());
517 _failures = true;
518 return;
519 }
520 // Nmethod has at least one oop in the current region
521 _has_oops_in_region = true;
522 }
523 }
524 }
525
526 public:
527 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
528 _hr(hr), _failures(false), _has_oops_in_region(false) {}
529
530 void do_oop(narrowOop* p) { do_oop_work(p); }
531 void do_oop(oop* p) { do_oop_work(p); }
532
533 bool failures() { return _failures; }
534 bool has_oops_in_region() { return _has_oops_in_region; }
535 };
536
537 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
538 const HeapRegion* _hr;
539 bool _failures;
540 public:
541 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
542 _hr(hr), _failures(false) {}
543
544 void do_code_blob(CodeBlob* cb) {
545 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
546 if (nm != NULL) {
547 // Verify that the nemthod is live
548 if (!nm->is_alive()) {
549 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has dead nmethod "
550 PTR_FORMAT" in its strong code roots",
551 _hr->bottom(), _hr->end(), nm);
552 _failures = true;
553 } else {
554 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
555 nm->oops_do(&oop_cl);
556 if (!oop_cl.has_oops_in_region()) {
557 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has nmethod "
558 PTR_FORMAT" in its strong code roots "
559 "with no pointers into region",
560 _hr->bottom(), _hr->end(), nm);
561 _failures = true;
562 } else if (oop_cl.failures()) {
563 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has other "
564 "failures for nmethod "PTR_FORMAT,
565 _hr->bottom(), _hr->end(), nm);
566 _failures = true;
567 }
568 }
569 }
570 }
571
572 bool failures() { return _failures; }
573 };
574
575 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
576 if (!G1VerifyHeapRegionCodeRoots) {
577 // We're not verifying code roots.
578 return;
579 }
580 if (vo == VerifyOption_G1UseMarkWord) {
581 // Marking verification during a full GC is performed after class
582 // unloading, code cache unloading, etc so the strong code roots
583 // attached to each heap region are in an inconsistent state. They won't
584 // be consistent until the strong code roots are rebuilt after the
585 // actual GC. Skip verifying the strong code roots in this particular
586 // time.
587 assert(VerifyDuringGC, "only way to get here");
588 return;
589 }
590
591 HeapRegionRemSet* hrrs = rem_set();
592 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
593
594 // if this region is empty then there should be no entries
595 // on its strong code root list
596 if (is_empty()) {
597 if (strong_code_roots_length > 0) {
598 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is empty "
599 "but has "SIZE_FORMAT" code root entries",
600 bottom(), end(), strong_code_roots_length);
601 *failures = true;
602 }
603 return;
604 }
605
606 if (is_continues_humongous()) {
607 if (strong_code_roots_length > 0) {
608 gclog_or_tty->print_cr("region "HR_FORMAT" is a continuation of a humongous "
609 "region but has "SIZE_FORMAT" code root entries",
610 HR_FORMAT_PARAMS(this), strong_code_roots_length);
611 *failures = true;
612 }
613 return;
614 }
615
616 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
617 strong_code_roots_do(&cb_cl);
618
619 if (cb_cl.failures()) {
620 *failures = true;
621 }
622 }
623
624 void HeapRegion::print() const { print_on(gclog_or_tty); }
625 void HeapRegion::print_on(outputStream* st) const {
626 st->print("AC%4u", allocation_context());
627
628 st->print(" %2s", get_short_type_str());
629 if (in_collection_set())
630 st->print(" CS");
631 else
632 st->print(" ");
633 st->print(" TS %5d", _gc_time_stamp);
634 st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT,
635 prev_top_at_mark_start(), next_top_at_mark_start());
636 G1OffsetTableContigSpace::print_on(st);
637 }
638
639 class VerifyLiveClosure: public OopClosure {
640 private:
641 G1CollectedHeap* _g1h;
642 CardTableModRefBS* _bs;
643 oop _containing_obj;
644 bool _failures;
645 int _n_failures;
646 VerifyOption _vo;
647 public:
648 // _vo == UsePrevMarking -> use "prev" marking information,
649 // _vo == UseNextMarking -> use "next" marking information,
650 // _vo == UseMarkWord -> use mark word from object header.
651 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) :
652 _g1h(g1h), _bs(NULL), _containing_obj(NULL),
653 _failures(false), _n_failures(0), _vo(vo)
654 {
655 BarrierSet* bs = _g1h->barrier_set();
656 if (bs->is_a(BarrierSet::CardTableModRef))
657 _bs = (CardTableModRefBS*)bs;
658 }
659
660 void set_containing_obj(oop obj) {
661 _containing_obj = obj;
662 }
663
664 bool failures() { return _failures; }
665 int n_failures() { return _n_failures; }
666
667 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
668 virtual void do_oop( oop* p) { do_oop_work(p); }
669
670 void print_object(outputStream* out, oop obj) {
671 #ifdef PRODUCT
672 Klass* k = obj->klass();
673 const char* class_name = InstanceKlass::cast(k)->external_name();
674 out->print_cr("class name %s", class_name);
675 #else // PRODUCT
676 obj->print_on(out);
677 #endif // PRODUCT
678 }
679
680 template <class T>
681 void do_oop_work(T* p) {
682 assert(_containing_obj != NULL, "Precondition");
683 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
684 "Precondition");
685 T heap_oop = oopDesc::load_heap_oop(p);
686 if (!oopDesc::is_null(heap_oop)) {
687 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
688 bool failed = false;
689 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
690 MutexLockerEx x(ParGCRareEvent_lock,
691 Mutex::_no_safepoint_check_flag);
692
693 if (!_failures) {
694 gclog_or_tty->cr();
695 gclog_or_tty->print_cr("----------");
696 }
697 if (!_g1h->is_in_closed_subset(obj)) {
698 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
699 gclog_or_tty->print_cr("Field "PTR_FORMAT
700 " of live obj "PTR_FORMAT" in region "
701 "["PTR_FORMAT", "PTR_FORMAT")",
702 p, (void*) _containing_obj,
703 from->bottom(), from->end());
704 print_object(gclog_or_tty, _containing_obj);
705 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" not in the heap",
706 (void*) obj);
707 } else {
708 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
709 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
710 gclog_or_tty->print_cr("Field "PTR_FORMAT
711 " of live obj "PTR_FORMAT" in region "
712 "["PTR_FORMAT", "PTR_FORMAT")",
713 p, (void*) _containing_obj,
714 from->bottom(), from->end());
715 print_object(gclog_or_tty, _containing_obj);
716 gclog_or_tty->print_cr("points to dead obj "PTR_FORMAT" in region "
717 "["PTR_FORMAT", "PTR_FORMAT")",
718 (void*) obj, to->bottom(), to->end());
719 print_object(gclog_or_tty, obj);
720 }
721 gclog_or_tty->print_cr("----------");
722 gclog_or_tty->flush();
723 _failures = true;
724 failed = true;
725 _n_failures++;
726 }
727
728 if (!_g1h->full_collection() || G1VerifyRSetsDuringFullGC) {
729 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
730 HeapRegion* to = _g1h->heap_region_containing(obj);
731 if (from != NULL && to != NULL &&
732 from != to &&
733 !to->is_humongous()) {
734 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
735 jbyte cv_field = *_bs->byte_for_const(p);
736 const jbyte dirty = CardTableModRefBS::dirty_card_val();
737
738 bool is_bad = !(from->is_young()
739 || to->rem_set()->contains_reference(p)
740 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
741 (_containing_obj->is_objArray() ?
742 cv_field == dirty
743 : cv_obj == dirty || cv_field == dirty));
744 if (is_bad) {
745 MutexLockerEx x(ParGCRareEvent_lock,
746 Mutex::_no_safepoint_check_flag);
747
748 if (!_failures) {
749 gclog_or_tty->cr();
750 gclog_or_tty->print_cr("----------");
751 }
752 gclog_or_tty->print_cr("Missing rem set entry:");
753 gclog_or_tty->print_cr("Field "PTR_FORMAT" "
754 "of obj "PTR_FORMAT", "
755 "in region "HR_FORMAT,
756 p, (void*) _containing_obj,
757 HR_FORMAT_PARAMS(from));
758 _containing_obj->print_on(gclog_or_tty);
759 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" "
760 "in region "HR_FORMAT,
761 (void*) obj,
762 HR_FORMAT_PARAMS(to));
763 obj->print_on(gclog_or_tty);
764 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
765 cv_obj, cv_field);
766 gclog_or_tty->print_cr("----------");
767 gclog_or_tty->flush();
768 _failures = true;
769 if (!failed) _n_failures++;
770 }
771 }
772 }
773 }
774 }
775 };
776
777 // This really ought to be commoned up into OffsetTableContigSpace somehow.
778 // We would need a mechanism to make that code skip dead objects.
779
780 void HeapRegion::verify(VerifyOption vo,
781 bool* failures) const {
782 G1CollectedHeap* g1 = G1CollectedHeap::heap();
783 *failures = false;
784 HeapWord* p = bottom();
785 HeapWord* prev_p = NULL;
786 VerifyLiveClosure vl_cl(g1, vo);
787 bool is_region_humongous = is_humongous();
788 size_t object_num = 0;
789 while (p < top()) {
790 oop obj = oop(p);
791 size_t obj_size = block_size(p);
792 object_num += 1;
793
794 if (is_region_humongous != g1->is_humongous(obj_size) &&
795 !g1->is_obj_dead(obj, this)) { // Dead objects may have bigger block_size since they span several objects.
796 gclog_or_tty->print_cr("obj "PTR_FORMAT" is of %shumongous size ("
797 SIZE_FORMAT" words) in a %shumongous region",
798 p, g1->is_humongous(obj_size) ? "" : "non-",
799 obj_size, is_region_humongous ? "" : "non-");
800 *failures = true;
801 return;
802 }
803
804 if (!g1->is_obj_dead_cond(obj, this, vo)) {
805 if (obj->is_oop()) {
806 Klass* klass = obj->klass();
807 bool is_metaspace_object = Metaspace::contains(klass) ||
808 (vo == VerifyOption_G1UsePrevMarking &&
809 ClassLoaderDataGraph::unload_list_contains(klass));
810 if (!is_metaspace_object) {
811 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
812 "not metadata", klass, (void *)obj);
813 *failures = true;
814 return;
815 } else if (!klass->is_klass()) {
816 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
817 "not a klass", klass, (void *)obj);
818 *failures = true;
819 return;
820 } else {
821 vl_cl.set_containing_obj(obj);
822 obj->oop_iterate_no_header(&vl_cl);
823 if (vl_cl.failures()) {
824 *failures = true;
825 }
826 if (G1MaxVerifyFailures >= 0 &&
827 vl_cl.n_failures() >= G1MaxVerifyFailures) {
828 return;
829 }
830 }
831 } else {
832 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", (void *)obj);
833 *failures = true;
834 return;
835 }
836 }
837 prev_p = p;
838 p += obj_size;
839 }
840
841 if (!is_young() && !is_empty()) {
842 _offsets.verify();
843 }
844
845 if (p != top()) {
846 gclog_or_tty->print_cr("end of last object "PTR_FORMAT" "
847 "does not match top "PTR_FORMAT, p, top());
848 *failures = true;
849 return;
850 }
851
852 HeapWord* the_end = end();
853 assert(p == top(), "it should still hold");
854 // Do some extra BOT consistency checking for addresses in the
855 // range [top, end). BOT look-ups in this range should yield
856 // top. No point in doing that if top == end (there's nothing there).
857 if (p < the_end) {
858 // Look up top
859 HeapWord* addr_1 = p;
860 HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
861 if (b_start_1 != p) {
862 gclog_or_tty->print_cr("BOT look up for top: "PTR_FORMAT" "
863 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
864 addr_1, b_start_1, p);
865 *failures = true;
866 return;
867 }
868
869 // Look up top + 1
870 HeapWord* addr_2 = p + 1;
871 if (addr_2 < the_end) {
872 HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
873 if (b_start_2 != p) {
874 gclog_or_tty->print_cr("BOT look up for top + 1: "PTR_FORMAT" "
875 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
876 addr_2, b_start_2, p);
877 *failures = true;
878 return;
879 }
880 }
881
882 // Look up an address between top and end
883 size_t diff = pointer_delta(the_end, p) / 2;
884 HeapWord* addr_3 = p + diff;
885 if (addr_3 < the_end) {
886 HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
887 if (b_start_3 != p) {
888 gclog_or_tty->print_cr("BOT look up for top + diff: "PTR_FORMAT" "
889 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
890 addr_3, b_start_3, p);
891 *failures = true;
892 return;
893 }
894 }
895
896 // Look up end - 1
897 HeapWord* addr_4 = the_end - 1;
898 HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
899 if (b_start_4 != p) {
900 gclog_or_tty->print_cr("BOT look up for end - 1: "PTR_FORMAT" "
901 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
902 addr_4, b_start_4, p);
903 *failures = true;
904 return;
905 }
906 }
907
908 if (is_region_humongous && object_num > 1) {
909 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous "
910 "but has "SIZE_FORMAT", objects",
911 bottom(), end(), object_num);
912 *failures = true;
913 return;
914 }
915
916 verify_strong_code_roots(vo, failures);
917 }
918
919 void HeapRegion::verify() const {
920 bool dummy = false;
921 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
922 }
923
924 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
925 scan_and_forward(this, cp);
926 }
927
928 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
929 // away eventually.
930
931 void G1OffsetTableContigSpace::clear(bool mangle_space) {
932 set_top(bottom());
933 _scan_top = bottom();
934 CompactibleSpace::clear(mangle_space);
935 reset_bot();
936 }
937
938 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
939 Space::set_bottom(new_bottom);
940 _offsets.set_bottom(new_bottom);
941 }
942
943 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
944 Space::set_end(new_end);
945 _offsets.resize(new_end - bottom());
946 }
947
948 void G1OffsetTableContigSpace::print() const {
949 print_short();
950 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
951 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
952 bottom(), top(), _offsets.threshold(), end());
953 }
954
955 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
956 return _offsets.initialize_threshold();
957 }
958
959 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
960 HeapWord* end) {
961 _offsets.alloc_block(start, end);
962 return _offsets.threshold();
963 }
964
965 HeapWord* G1OffsetTableContigSpace::scan_top() const {
966 G1CollectedHeap* g1h = G1CollectedHeap::heap();
967 HeapWord* local_top = top();
968 OrderAccess::loadload();
969 const unsigned local_time_stamp = _gc_time_stamp;
970 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
971 if (local_time_stamp < g1h->get_gc_time_stamp()) {
972 return local_top;
973 } else {
974 return _scan_top;
975 }
976 }
977
978 void G1OffsetTableContigSpace::record_timestamp() {
979 G1CollectedHeap* g1h = G1CollectedHeap::heap();
980 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
981
982 if (_gc_time_stamp < curr_gc_time_stamp) {
983 // Setting the time stamp here tells concurrent readers to look at
984 // scan_top to know the maximum allowed address to look at.
985
986 // scan_top should be bottom for all regions except for the
987 // retained old alloc region which should have scan_top == top
988 HeapWord* st = _scan_top;
989 guarantee(st == _bottom || st == _top, "invariant");
990
991 _gc_time_stamp = curr_gc_time_stamp;
992 }
993 }
994
995 void G1OffsetTableContigSpace::record_retained_region() {
996 // scan_top is the maximum address where it's safe for the next gc to
997 // scan this region.
998 _scan_top = top();
999 }
1000
1001 void G1OffsetTableContigSpace::safe_object_iterate(ObjectClosure* blk) {
1002 object_iterate(blk);
1003 }
1004
1005 void G1OffsetTableContigSpace::object_iterate(ObjectClosure* blk) {
1006 HeapWord* p = bottom();
1007 while (p < top()) {
1008 if (block_is_obj(p)) {
1009 blk->do_object(oop(p));
1010 }
1011 p += block_size(p);
1012 }
1013 }
1014
1015 G1OffsetTableContigSpace::
1016 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
1017 MemRegion mr) :
1018 _offsets(sharedOffsetArray, mr),
1019 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
1020 _gc_time_stamp(0)
1021 {
1022 _offsets.set_space(this);
1023 }
1024
1025 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
1026 CompactibleSpace::initialize(mr, clear_space, mangle_space);
1027 _top = bottom();
1028 _scan_top = bottom();
1029 set_saved_mark_word(NULL);
1030 reset_bot();
1031 }
1032