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