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 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(0 <= marked_bytes && marked_bytes <= used(),
329 err_msg("marked: "SIZE_FORMAT" used: "SIZE_FORMAT,
330 marked_bytes, used()));
331 _prev_top_at_mark_start = top();
332 _prev_marked_bytes = marked_bytes;
333 }
334
335 HeapWord*
336 HeapRegion::object_iterate_mem_careful(MemRegion mr,
337 ObjectClosure* cl) {
338 G1CollectedHeap* g1h = G1CollectedHeap::heap();
339 // We used to use "block_start_careful" here. But we're actually happy
340 // to update the BOT while we do this...
341 HeapWord* cur = block_start(mr.start());
342 mr = mr.intersection(used_region());
343 if (mr.is_empty()) return NULL;
344 // Otherwise, find the obj that extends onto mr.start().
345
346 assert(cur <= mr.start()
347 && (oop(cur)->klass_or_null() == NULL ||
348 cur + oop(cur)->size() > mr.start()),
349 "postcondition of block_start");
350 oop obj;
351 while (cur < mr.end()) {
352 obj = oop(cur);
353 if (obj->klass_or_null() == NULL) {
354 // Ran into an unparseable point.
355 return cur;
356 } else if (!g1h->is_obj_dead(obj)) {
357 cl->do_object(obj);
358 }
359 cur += block_size(cur);
360 }
361 return NULL;
362 }
363
364 HeapWord*
365 HeapRegion::
366 oops_on_card_seq_iterate_careful(MemRegion mr,
367 FilterOutOfRegionClosure* cl,
368 bool filter_young,
369 jbyte* card_ptr) {
370 // Currently, we should only have to clean the card if filter_young
371 // is true and vice versa.
372 if (filter_young) {
373 assert(card_ptr != NULL, "pre-condition");
374 } else {
375 assert(card_ptr == NULL, "pre-condition");
376 }
377 G1CollectedHeap* g1h = G1CollectedHeap::heap();
378
379 // If we're within a stop-world GC, then we might look at a card in a
380 // GC alloc region that extends onto a GC LAB, which may not be
381 // parseable. Stop such at the "scan_top" of the region.
382 if (g1h->is_gc_active()) {
383 mr = mr.intersection(MemRegion(bottom(), scan_top()));
384 } else {
385 mr = mr.intersection(used_region());
386 }
387 if (mr.is_empty()) return NULL;
388 // Otherwise, find the obj that extends onto mr.start().
389
390 // The intersection of the incoming mr (for the card) and the
391 // allocated part of the region is non-empty. This implies that
392 // we have actually allocated into this region. The code in
393 // G1CollectedHeap.cpp that allocates a new region sets the
394 // is_young tag on the region before allocating. Thus we
395 // safely know if this region is young.
396 if (is_young() && filter_young) {
397 return NULL;
398 }
399
400 assert(!is_young(), "check value of filter_young");
401
402 // We can only clean the card here, after we make the decision that
403 // the card is not young. And we only clean the card if we have been
404 // asked to (i.e., card_ptr != NULL).
405 if (card_ptr != NULL) {
406 *card_ptr = CardTableModRefBS::clean_card_val();
407 // We must complete this write before we do any of the reads below.
408 OrderAccess::storeload();
409 }
410
411 // Cache the boundaries of the memory region in some const locals
412 HeapWord* const start = mr.start();
413 HeapWord* const end = mr.end();
414
415 // We used to use "block_start_careful" here. But we're actually happy
416 // to update the BOT while we do this...
417 HeapWord* cur = block_start(start);
418 assert(cur <= start, "Postcondition");
419
420 oop obj;
421
422 HeapWord* next = cur;
423 while (next <= start) {
424 cur = next;
425 obj = oop(cur);
426 if (obj->klass_or_null() == NULL) {
427 // Ran into an unparseable point.
428 return cur;
429 }
430 // Otherwise...
431 next = cur + block_size(cur);
432 }
433
434 // If we finish the above loop...We have a parseable object that
435 // begins on or before the start of the memory region, and ends
436 // inside or spans the entire region.
437 assert(cur <= start, "Loop postcondition");
438 assert(obj->klass_or_null() != NULL, "Loop invariant");
439
440 do {
441 obj = oop(cur);
442 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant");
443 if (obj->klass_or_null() == NULL) {
444 // Ran into an unparseable point.
445 return cur;
446 }
447
448 // Advance the current pointer. "obj" still points to the object to iterate.
449 cur = cur + block_size(cur);
450
451 if (!g1h->is_obj_dead(obj)) {
452 // Non-objArrays are sometimes marked imprecise at the object start. We
453 // always need to iterate over them in full.
454 // We only iterate over object arrays in full if they are completely contained
455 // in the memory region.
456 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur < end)) {
457 obj->oop_iterate(cl);
458 } else {
459 obj->oop_iterate(cl, mr);
460 }
461 }
462 } while (cur < end);
463
464 return NULL;
465 }
466
467 // Code roots support
468
469 void HeapRegion::add_strong_code_root(nmethod* nm) {
470 HeapRegionRemSet* hrrs = rem_set();
471 hrrs->add_strong_code_root(nm);
472 }
473
474 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
475 assert_locked_or_safepoint(CodeCache_lock);
476 HeapRegionRemSet* hrrs = rem_set();
477 hrrs->add_strong_code_root_locked(nm);
478 }
479
480 void HeapRegion::remove_strong_code_root(nmethod* nm) {
481 HeapRegionRemSet* hrrs = rem_set();
482 hrrs->remove_strong_code_root(nm);
483 }
484
485 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
486 HeapRegionRemSet* hrrs = rem_set();
487 hrrs->strong_code_roots_do(blk);
488 }
489
490 class VerifyStrongCodeRootOopClosure: public OopClosure {
491 const HeapRegion* _hr;
492 nmethod* _nm;
493 bool _failures;
494 bool _has_oops_in_region;
495
496 template <class T> void do_oop_work(T* p) {
497 T heap_oop = oopDesc::load_heap_oop(p);
498 if (!oopDesc::is_null(heap_oop)) {
499 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
500
501 // Note: not all the oops embedded in the nmethod are in the
502 // current region. We only look at those which are.
503 if (_hr->is_in(obj)) {
504 // Object is in the region. Check that its less than top
505 if (_hr->top() <= (HeapWord*)obj) {
506 // Object is above top
507 gclog_or_tty->print_cr("Object "PTR_FORMAT" in region "
508 "["PTR_FORMAT", "PTR_FORMAT") is above "
509 "top "PTR_FORMAT,
510 (void *)obj, _hr->bottom(), _hr->end(), _hr->top());
511 _failures = true;
512 return;
513 }
514 // Nmethod has at least one oop in the current region
515 _has_oops_in_region = true;
516 }
517 }
518 }
519
520 public:
521 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
522 _hr(hr), _failures(false), _has_oops_in_region(false) {}
523
524 void do_oop(narrowOop* p) { do_oop_work(p); }
525 void do_oop(oop* p) { do_oop_work(p); }
526
527 bool failures() { return _failures; }
528 bool has_oops_in_region() { return _has_oops_in_region; }
529 };
530
531 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
532 const HeapRegion* _hr;
533 bool _failures;
534 public:
535 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
536 _hr(hr), _failures(false) {}
537
538 void do_code_blob(CodeBlob* cb) {
539 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
540 if (nm != NULL) {
541 // Verify that the nemthod is live
542 if (!nm->is_alive()) {
543 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has dead nmethod "
544 PTR_FORMAT" in its strong code roots",
545 _hr->bottom(), _hr->end(), nm);
546 _failures = true;
547 } else {
548 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
549 nm->oops_do(&oop_cl);
550 if (!oop_cl.has_oops_in_region()) {
551 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has nmethod "
552 PTR_FORMAT" in its strong code roots "
553 "with no pointers into region",
554 _hr->bottom(), _hr->end(), nm);
555 _failures = true;
556 } else if (oop_cl.failures()) {
557 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] has other "
558 "failures for nmethod "PTR_FORMAT,
559 _hr->bottom(), _hr->end(), nm);
560 _failures = true;
561 }
562 }
563 }
564 }
565
566 bool failures() { return _failures; }
567 };
568
569 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
570 if (!G1VerifyHeapRegionCodeRoots) {
571 // We're not verifying code roots.
572 return;
573 }
574 if (vo == VerifyOption_G1UseMarkWord) {
575 // Marking verification during a full GC is performed after class
576 // unloading, code cache unloading, etc so the strong code roots
577 // attached to each heap region are in an inconsistent state. They won't
578 // be consistent until the strong code roots are rebuilt after the
579 // actual GC. Skip verifying the strong code roots in this particular
580 // time.
581 assert(VerifyDuringGC, "only way to get here");
582 return;
583 }
584
585 HeapRegionRemSet* hrrs = rem_set();
586 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
587
588 // if this region is empty then there should be no entries
589 // on its strong code root list
590 if (is_empty()) {
591 if (strong_code_roots_length > 0) {
592 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is empty "
593 "but has "SIZE_FORMAT" code root entries",
594 bottom(), end(), strong_code_roots_length);
595 *failures = true;
596 }
597 return;
598 }
599
600 if (is_continues_humongous()) {
601 if (strong_code_roots_length > 0) {
602 gclog_or_tty->print_cr("region "HR_FORMAT" is a continuation of a humongous "
603 "region but has "SIZE_FORMAT" code root entries",
604 HR_FORMAT_PARAMS(this), strong_code_roots_length);
605 *failures = true;
606 }
607 return;
608 }
609
610 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
611 strong_code_roots_do(&cb_cl);
612
613 if (cb_cl.failures()) {
614 *failures = true;
615 }
616 }
617
618 void HeapRegion::print() const { print_on(gclog_or_tty); }
619 void HeapRegion::print_on(outputStream* st) const {
620 st->print("AC%4u", allocation_context());
621
622 st->print(" %2s", get_short_type_str());
623 if (in_collection_set())
624 st->print(" CS");
625 else
626 st->print(" ");
627 st->print(" TS %5d", _gc_time_stamp);
628 st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT,
629 prev_top_at_mark_start(), next_top_at_mark_start());
630 G1OffsetTableContigSpace::print_on(st);
631 }
632
633 class VerifyLiveClosure: public OopClosure {
634 private:
635 G1CollectedHeap* _g1h;
636 CardTableModRefBS* _bs;
637 oop _containing_obj;
638 bool _failures;
639 int _n_failures;
640 VerifyOption _vo;
641 public:
642 // _vo == UsePrevMarking -> use "prev" marking information,
643 // _vo == UseNextMarking -> use "next" marking information,
644 // _vo == UseMarkWord -> use mark word from object header.
645 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) :
646 _g1h(g1h), _bs(NULL), _containing_obj(NULL),
647 _failures(false), _n_failures(0), _vo(vo)
648 {
649 BarrierSet* bs = _g1h->barrier_set();
650 if (bs->is_a(BarrierSet::CardTableModRef))
651 _bs = (CardTableModRefBS*)bs;
652 }
653
654 void set_containing_obj(oop obj) {
655 _containing_obj = obj;
656 }
657
658 bool failures() { return _failures; }
659 int n_failures() { return _n_failures; }
660
661 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
662 virtual void do_oop( oop* p) { do_oop_work(p); }
663
664 void print_object(outputStream* out, oop obj) {
665 #ifdef PRODUCT
666 Klass* k = obj->klass();
667 const char* class_name = InstanceKlass::cast(k)->external_name();
668 out->print_cr("class name %s", class_name);
669 #else // PRODUCT
670 obj->print_on(out);
671 #endif // PRODUCT
672 }
673
674 template <class T>
675 void do_oop_work(T* p) {
676 assert(_containing_obj != NULL, "Precondition");
677 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
678 "Precondition");
679 T heap_oop = oopDesc::load_heap_oop(p);
680 if (!oopDesc::is_null(heap_oop)) {
681 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
682 bool failed = false;
683 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
684 MutexLockerEx x(ParGCRareEvent_lock,
685 Mutex::_no_safepoint_check_flag);
686
687 if (!_failures) {
688 gclog_or_tty->cr();
689 gclog_or_tty->print_cr("----------");
690 }
691 if (!_g1h->is_in_closed_subset(obj)) {
692 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
693 gclog_or_tty->print_cr("Field "PTR_FORMAT
694 " of live obj "PTR_FORMAT" in region "
695 "["PTR_FORMAT", "PTR_FORMAT")",
696 p, (void*) _containing_obj,
697 from->bottom(), from->end());
698 print_object(gclog_or_tty, _containing_obj);
699 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" not in the heap",
700 (void*) obj);
701 } else {
702 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
703 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
704 gclog_or_tty->print_cr("Field "PTR_FORMAT
705 " of live obj "PTR_FORMAT" in region "
706 "["PTR_FORMAT", "PTR_FORMAT")",
707 p, (void*) _containing_obj,
708 from->bottom(), from->end());
709 print_object(gclog_or_tty, _containing_obj);
710 gclog_or_tty->print_cr("points to dead obj "PTR_FORMAT" in region "
711 "["PTR_FORMAT", "PTR_FORMAT")",
712 (void*) obj, to->bottom(), to->end());
713 print_object(gclog_or_tty, obj);
714 }
715 gclog_or_tty->print_cr("----------");
716 gclog_or_tty->flush();
717 _failures = true;
718 failed = true;
719 _n_failures++;
720 }
721
722 if (!_g1h->full_collection() || G1VerifyRSetsDuringFullGC) {
723 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
724 HeapRegion* to = _g1h->heap_region_containing(obj);
725 if (from != NULL && to != NULL &&
726 from != to &&
727 !to->is_humongous()) {
728 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
729 jbyte cv_field = *_bs->byte_for_const(p);
730 const jbyte dirty = CardTableModRefBS::dirty_card_val();
731
732 bool is_bad = !(from->is_young()
733 || to->rem_set()->contains_reference(p)
734 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
735 (_containing_obj->is_objArray() ?
736 cv_field == dirty
737 : cv_obj == dirty || cv_field == dirty));
738 if (is_bad) {
739 MutexLockerEx x(ParGCRareEvent_lock,
740 Mutex::_no_safepoint_check_flag);
741
742 if (!_failures) {
743 gclog_or_tty->cr();
744 gclog_or_tty->print_cr("----------");
745 }
746 gclog_or_tty->print_cr("Missing rem set entry:");
747 gclog_or_tty->print_cr("Field "PTR_FORMAT" "
748 "of obj "PTR_FORMAT", "
749 "in region "HR_FORMAT,
750 p, (void*) _containing_obj,
751 HR_FORMAT_PARAMS(from));
752 _containing_obj->print_on(gclog_or_tty);
753 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" "
754 "in region "HR_FORMAT,
755 (void*) obj,
756 HR_FORMAT_PARAMS(to));
757 obj->print_on(gclog_or_tty);
758 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
759 cv_obj, cv_field);
760 gclog_or_tty->print_cr("----------");
761 gclog_or_tty->flush();
762 _failures = true;
763 if (!failed) _n_failures++;
764 }
765 }
766 }
767 }
768 }
769 };
770
771 // This really ought to be commoned up into OffsetTableContigSpace somehow.
772 // We would need a mechanism to make that code skip dead objects.
773
774 void HeapRegion::verify(VerifyOption vo,
775 bool* failures) const {
776 G1CollectedHeap* g1 = G1CollectedHeap::heap();
777 *failures = false;
778 HeapWord* p = bottom();
779 HeapWord* prev_p = NULL;
780 VerifyLiveClosure vl_cl(g1, vo);
781 bool is_region_humongous = is_humongous();
782 size_t object_num = 0;
783 while (p < top()) {
784 oop obj = oop(p);
785 size_t obj_size = block_size(p);
786 object_num += 1;
787
788 if (is_region_humongous != g1->is_humongous(obj_size) &&
789 !g1->is_obj_dead(obj, this)) { // Dead objects may have bigger block_size since they span several objects.
790 gclog_or_tty->print_cr("obj "PTR_FORMAT" is of %shumongous size ("
791 SIZE_FORMAT" words) in a %shumongous region",
792 p, g1->is_humongous(obj_size) ? "" : "non-",
793 obj_size, is_region_humongous ? "" : "non-");
794 *failures = true;
795 return;
796 }
797
798 if (!g1->is_obj_dead_cond(obj, this, vo)) {
799 if (obj->is_oop()) {
800 Klass* klass = obj->klass();
801 bool is_metaspace_object = Metaspace::contains(klass) ||
802 (vo == VerifyOption_G1UsePrevMarking &&
803 ClassLoaderDataGraph::unload_list_contains(klass));
804 if (!is_metaspace_object) {
805 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
806 "not metadata", klass, (void *)obj);
807 *failures = true;
808 return;
809 } else if (!klass->is_klass()) {
810 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
811 "not a klass", klass, (void *)obj);
812 *failures = true;
813 return;
814 } else {
815 vl_cl.set_containing_obj(obj);
816 obj->oop_iterate_no_header(&vl_cl);
817 if (vl_cl.failures()) {
818 *failures = true;
819 }
820 if (G1MaxVerifyFailures >= 0 &&
821 vl_cl.n_failures() >= G1MaxVerifyFailures) {
822 return;
823 }
824 }
825 } else {
826 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", (void *)obj);
827 *failures = true;
828 return;
829 }
830 }
831 prev_p = p;
832 p += obj_size;
833 }
834
835 if (!is_young() && !is_empty()) {
836 _offsets.verify();
837 }
838
839 if (p != top()) {
840 gclog_or_tty->print_cr("end of last object "PTR_FORMAT" "
841 "does not match top "PTR_FORMAT, p, top());
842 *failures = true;
843 return;
844 }
845
846 HeapWord* the_end = end();
847 assert(p == top(), "it should still hold");
848 // Do some extra BOT consistency checking for addresses in the
849 // range [top, end). BOT look-ups in this range should yield
850 // top. No point in doing that if top == end (there's nothing there).
851 if (p < the_end) {
852 // Look up top
853 HeapWord* addr_1 = p;
854 HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
855 if (b_start_1 != p) {
856 gclog_or_tty->print_cr("BOT look up for top: "PTR_FORMAT" "
857 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
858 addr_1, b_start_1, p);
859 *failures = true;
860 return;
861 }
862
863 // Look up top + 1
864 HeapWord* addr_2 = p + 1;
865 if (addr_2 < the_end) {
866 HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
867 if (b_start_2 != p) {
868 gclog_or_tty->print_cr("BOT look up for top + 1: "PTR_FORMAT" "
869 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
870 addr_2, b_start_2, p);
871 *failures = true;
872 return;
873 }
874 }
875
876 // Look up an address between top and end
877 size_t diff = pointer_delta(the_end, p) / 2;
878 HeapWord* addr_3 = p + diff;
879 if (addr_3 < the_end) {
880 HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
881 if (b_start_3 != p) {
882 gclog_or_tty->print_cr("BOT look up for top + diff: "PTR_FORMAT" "
883 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
884 addr_3, b_start_3, p);
885 *failures = true;
886 return;
887 }
888 }
889
890 // Look up end - 1
891 HeapWord* addr_4 = the_end - 1;
892 HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
893 if (b_start_4 != p) {
894 gclog_or_tty->print_cr("BOT look up for end - 1: "PTR_FORMAT" "
895 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
896 addr_4, b_start_4, p);
897 *failures = true;
898 return;
899 }
900 }
901
902 if (is_region_humongous && object_num > 1) {
903 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous "
904 "but has "SIZE_FORMAT", objects",
905 bottom(), end(), object_num);
906 *failures = true;
907 return;
908 }
909
910 verify_strong_code_roots(vo, failures);
911 }
912
913 void HeapRegion::verify() const {
914 bool dummy = false;
915 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
916 }
917
918 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
919 scan_and_forward(this, cp);
920 }
921
922 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
923 // away eventually.
924
925 void G1OffsetTableContigSpace::clear(bool mangle_space) {
926 set_top(bottom());
927 _scan_top = bottom();
928 CompactibleSpace::clear(mangle_space);
929 reset_bot();
930 }
931
932 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
933 Space::set_bottom(new_bottom);
934 _offsets.set_bottom(new_bottom);
935 }
936
937 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
938 Space::set_end(new_end);
939 _offsets.resize(new_end - bottom());
940 }
941
942 void G1OffsetTableContigSpace::print() const {
943 print_short();
944 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
945 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
946 bottom(), top(), _offsets.threshold(), end());
947 }
948
949 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
950 return _offsets.initialize_threshold();
951 }
952
953 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
954 HeapWord* end) {
955 _offsets.alloc_block(start, end);
956 return _offsets.threshold();
957 }
958
959 HeapWord* G1OffsetTableContigSpace::scan_top() const {
960 G1CollectedHeap* g1h = G1CollectedHeap::heap();
961 HeapWord* local_top = top();
962 OrderAccess::loadload();
963 const unsigned local_time_stamp = _gc_time_stamp;
964 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
965 if (local_time_stamp < g1h->get_gc_time_stamp()) {
966 return local_top;
967 } else {
968 return _scan_top;
969 }
970 }
971
972 void G1OffsetTableContigSpace::record_timestamp() {
973 G1CollectedHeap* g1h = G1CollectedHeap::heap();
974 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
975
976 if (_gc_time_stamp < curr_gc_time_stamp) {
977 // Setting the time stamp here tells concurrent readers to look at
978 // scan_top to know the maximum allowed address to look at.
979
980 // scan_top should be bottom for all regions except for the
981 // retained old alloc region which should have scan_top == top
982 HeapWord* st = _scan_top;
983 guarantee(st == _bottom || st == _top, "invariant");
984
985 _gc_time_stamp = curr_gc_time_stamp;
986 }
987 }
988
989 void G1OffsetTableContigSpace::record_retained_region() {
990 // scan_top is the maximum address where it's safe for the next gc to
991 // scan this region.
992 _scan_top = top();
993 }
994
995 void G1OffsetTableContigSpace::safe_object_iterate(ObjectClosure* blk) {
996 object_iterate(blk);
997 }
998
999 void G1OffsetTableContigSpace::object_iterate(ObjectClosure* blk) {
1000 HeapWord* p = bottom();
1001 while (p < top()) {
1002 if (block_is_obj(p)) {
1003 blk->do_object(oop(p));
1004 }
1005 p += block_size(p);
1006 }
1007 }
1008
1009 G1OffsetTableContigSpace::
1010 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
1011 MemRegion mr) :
1012 _offsets(sharedOffsetArray, mr),
1013 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
1014 _gc_time_stamp(0)
1015 {
1016 _offsets.set_space(this);
1017 }
1018
1019 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
1020 CompactibleSpace::initialize(mr, clear_space, mangle_space);
1021 _top = bottom();
1022 _scan_top = bottom();
1023 set_saved_mark_word(NULL);
1024 reset_bot();
1025 }
1026