1 /*
2 * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "code/nmethod.hpp"
27 #include "gc/g1/g1BlockOffsetTable.inline.hpp"
28 #include "gc/g1/g1CollectedHeap.inline.hpp"
29 #include "gc/g1/g1OopClosures.inline.hpp"
30 #include "gc/g1/heapRegion.inline.hpp"
31 #include "gc/g1/heapRegionBounds.inline.hpp"
32 #include "gc/g1/heapRegionManager.inline.hpp"
33 #include "gc/g1/heapRegionRemSet.hpp"
34 #include "gc/shared/genOopClosures.inline.hpp"
35 #include "gc/shared/liveRange.hpp"
36 #include "gc/shared/space.inline.hpp"
37 #include "logging/log.hpp"
38 #include "memory/iterator.hpp"
39 #include "oops/oop.inline.hpp"
40 #include "runtime/atomic.inline.hpp"
41 #include "runtime/orderAccess.inline.hpp"
42
43 int HeapRegion::LogOfHRGrainBytes = 0;
44 int HeapRegion::LogOfHRGrainWords = 0;
45 size_t HeapRegion::GrainBytes = 0;
46 size_t HeapRegion::GrainWords = 0;
47 size_t HeapRegion::CardsPerRegion = 0;
48
49 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
50 HeapRegion* hr,
51 G1ParPushHeapRSClosure* cl,
52 CardTableModRefBS::PrecisionStyle precision) :
53 DirtyCardToOopClosure(hr, cl, precision, NULL),
54 _hr(hr), _rs_scan(cl), _g1(g1) { }
55
56 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
57 OopClosure* oc) :
58 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
59
60 void HeapRegionDCTOC::walk_mem_region(MemRegion mr,
61 HeapWord* bottom,
62 HeapWord* top) {
63 G1CollectedHeap* g1h = _g1;
64 size_t oop_size;
65 HeapWord* cur = bottom;
66
67 // Start filtering what we add to the remembered set. If the object is
68 // not considered dead, either because it is marked (in the mark bitmap)
69 // or it was allocated after marking finished, then we add it. Otherwise
70 // we can safely ignore the object.
71 if (!g1h->is_obj_dead(oop(cur))) {
72 oop_size = oop(cur)->oop_iterate_size(_rs_scan, mr);
73 } else {
74 oop_size = _hr->block_size(cur);
75 }
76
77 cur += oop_size;
78
79 if (cur < top) {
80 oop cur_oop = oop(cur);
81 oop_size = _hr->block_size(cur);
82 HeapWord* next_obj = cur + oop_size;
83 while (next_obj < top) {
84 // Keep filtering the remembered set.
85 if (!g1h->is_obj_dead(cur_oop)) {
86 // Bottom lies entirely below top, so we can call the
87 // non-memRegion version of oop_iterate below.
88 cur_oop->oop_iterate(_rs_scan);
89 }
90 cur = next_obj;
91 cur_oop = oop(cur);
92 oop_size = _hr->block_size(cur);
93 next_obj = cur + oop_size;
94 }
95
96 // Last object. Need to do dead-obj filtering here too.
97 if (!g1h->is_obj_dead(oop(cur))) {
98 oop(cur)->oop_iterate(_rs_scan, mr);
99 }
100 }
101 }
102
103 size_t HeapRegion::max_region_size() {
104 return HeapRegionBounds::max_size();
105 }
106
107 size_t HeapRegion::min_region_size_in_words() {
108 return HeapRegionBounds::min_size() >> LogHeapWordSize;
109 }
110
111 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
112 size_t region_size = G1HeapRegionSize;
113 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
114 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
115 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(),
116 HeapRegionBounds::min_size());
117 }
118
119 int region_size_log = log2_long((jlong) region_size);
120 // Recalculate the region size to make sure it's a power of
121 // 2. This means that region_size is the largest power of 2 that's
122 // <= what we've calculated so far.
123 region_size = ((size_t)1 << region_size_log);
124
125 // Now make sure that we don't go over or under our limits.
126 if (region_size < HeapRegionBounds::min_size()) {
127 region_size = HeapRegionBounds::min_size();
128 } else if (region_size > HeapRegionBounds::max_size()) {
129 region_size = HeapRegionBounds::max_size();
130 }
131
132 // And recalculate the log.
133 region_size_log = log2_long((jlong) region_size);
134
135 // Now, set up the globals.
136 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
137 LogOfHRGrainBytes = region_size_log;
138
139 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
140 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
141
142 guarantee(GrainBytes == 0, "we should only set it once");
143 // The cast to int is safe, given that we've bounded region_size by
144 // MIN_REGION_SIZE and MAX_REGION_SIZE.
145 GrainBytes = region_size;
146
147 guarantee(GrainWords == 0, "we should only set it once");
148 GrainWords = GrainBytes >> LogHeapWordSize;
149 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
150
151 guarantee(CardsPerRegion == 0, "we should only set it once");
152 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
153 }
154
155 void HeapRegion::reset_after_compaction() {
156 G1OffsetTableContigSpace::reset_after_compaction();
157 // After a compaction the mark bitmap is invalid, so we must
158 // treat all objects as being inside the unmarked area.
159 zero_marked_bytes();
160 init_top_at_mark_start();
161 }
162
163 void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
164 assert(_humongous_start_region == NULL,
165 "we should have already filtered out humongous regions");
166 assert(!in_collection_set(),
167 "Should not clear heap region %u in the collection set", hrm_index());
168
169 set_allocation_context(AllocationContext::system());
170 set_young_index_in_cset(-1);
171 uninstall_surv_rate_group();
172 set_free();
173 reset_pre_dummy_top();
174
175 if (!par) {
176 // If this is parallel, this will be done later.
177 HeapRegionRemSet* hrrs = rem_set();
178 if (locked) {
179 hrrs->clear_locked();
180 } else {
181 hrrs->clear();
182 }
183 }
184 zero_marked_bytes();
185
186 _offsets.resize(HeapRegion::GrainWords);
187 init_top_at_mark_start();
188 if (clear_space) clear(SpaceDecorator::Mangle);
189 }
190
191 void HeapRegion::par_clear() {
192 assert(used() == 0, "the region should have been already cleared");
193 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
194 HeapRegionRemSet* hrrs = rem_set();
195 hrrs->clear();
196 CardTableModRefBS* ct_bs =
197 barrier_set_cast<CardTableModRefBS>(G1CollectedHeap::heap()->barrier_set());
198 ct_bs->clear(MemRegion(bottom(), end()));
199 }
200
201 void HeapRegion::calc_gc_efficiency() {
202 // GC efficiency is the ratio of how much space would be
203 // reclaimed over how long we predict it would take to reclaim it.
204 G1CollectedHeap* g1h = G1CollectedHeap::heap();
205 G1CollectorPolicy* g1p = g1h->g1_policy();
206
207 // Retrieve a prediction of the elapsed time for this region for
208 // a mixed gc because the region will only be evacuated during a
209 // mixed gc.
210 double region_elapsed_time_ms =
211 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
212 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
213 }
214
215 void HeapRegion::set_starts_humongous(HeapWord* obj_top, size_t fill_size) {
216 assert(!is_humongous(), "sanity / pre-condition");
217 assert(top() == bottom(), "should be empty");
218
219 _type.set_starts_humongous();
220 _humongous_start_region = this;
221
222 _offsets.set_for_starts_humongous(obj_top, fill_size);
223 }
224
225 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) {
226 assert(!is_humongous(), "sanity / pre-condition");
227 assert(top() == bottom(), "should be empty");
228 assert(first_hr->is_starts_humongous(), "pre-condition");
229
230 _type.set_continues_humongous();
231 _humongous_start_region = first_hr;
232 }
233
234 void HeapRegion::clear_humongous() {
235 assert(is_humongous(), "pre-condition");
236
237 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
238 _humongous_start_region = NULL;
239 }
240
241 HeapRegion::HeapRegion(uint hrm_index,
242 G1BlockOffsetSharedArray* sharedOffsetArray,
243 MemRegion mr) :
244 G1OffsetTableContigSpace(sharedOffsetArray, mr),
245 _hrm_index(hrm_index),
246 _allocation_context(AllocationContext::system()),
247 _humongous_start_region(NULL),
248 _next_in_special_set(NULL),
249 _evacuation_failed(false),
250 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
251 _next_young_region(NULL),
252 _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL),
253 #ifdef ASSERT
254 _containing_set(NULL),
255 #endif // ASSERT
256 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
257 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
258 _predicted_bytes_to_copy(0)
259 {
260 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
261
262 initialize(mr);
263 }
264
265 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
266 assert(_rem_set->is_empty(), "Remembered set must be empty");
267
268 G1OffsetTableContigSpace::initialize(mr, clear_space, mangle_space);
269
270 hr_clear(false /*par*/, false /*clear_space*/);
271 set_top(bottom());
272 record_timestamp();
273 }
274
275 CompactibleSpace* HeapRegion::next_compaction_space() const {
276 return G1CollectedHeap::heap()->next_compaction_region(this);
277 }
278
279 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
280 bool during_conc_mark) {
281 // We always recreate the prev marking info and we'll explicitly
282 // mark all objects we find to be self-forwarded on the prev
283 // bitmap. So all objects need to be below PTAMS.
284 _prev_marked_bytes = 0;
285
286 if (during_initial_mark) {
287 // During initial-mark, we'll also explicitly mark all objects
288 // we find to be self-forwarded on the next bitmap. So all
289 // objects need to be below NTAMS.
290 _next_top_at_mark_start = top();
291 _next_marked_bytes = 0;
292 } else if (during_conc_mark) {
293 // During concurrent mark, all objects in the CSet (including
294 // the ones we find to be self-forwarded) are implicitly live.
295 // So all objects need to be above NTAMS.
296 _next_top_at_mark_start = bottom();
297 _next_marked_bytes = 0;
298 }
299 }
300
301 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
302 bool during_conc_mark,
303 size_t marked_bytes) {
304 assert(marked_bytes <= used(),
305 "marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used());
306 _prev_top_at_mark_start = top();
307 _prev_marked_bytes = marked_bytes;
308 }
309
310 HeapWord*
311 HeapRegion::object_iterate_mem_careful(MemRegion mr,
312 ObjectClosure* cl) {
313 G1CollectedHeap* g1h = G1CollectedHeap::heap();
314 // We used to use "block_start_careful" here. But we're actually happy
315 // to update the BOT while we do this...
316 HeapWord* cur = block_start(mr.start());
317 mr = mr.intersection(used_region());
318 if (mr.is_empty()) return NULL;
319 // Otherwise, find the obj that extends onto mr.start().
320
321 assert(cur <= mr.start()
322 && (oop(cur)->klass_or_null() == NULL ||
323 cur + oop(cur)->size() > mr.start()),
324 "postcondition of block_start");
325 oop obj;
326 while (cur < mr.end()) {
327 obj = oop(cur);
328 if (obj->klass_or_null() == NULL) {
329 // Ran into an unparseable point.
330 return cur;
331 } else if (!g1h->is_obj_dead(obj)) {
332 cl->do_object(obj);
333 }
334 cur += block_size(cur);
335 }
336 return NULL;
337 }
338
339 HeapWord*
340 HeapRegion::
341 oops_on_card_seq_iterate_careful(MemRegion mr,
342 FilterOutOfRegionClosure* cl,
343 bool filter_young,
344 jbyte* card_ptr) {
345 // Currently, we should only have to clean the card if filter_young
346 // is true and vice versa.
347 if (filter_young) {
348 assert(card_ptr != NULL, "pre-condition");
349 } else {
350 assert(card_ptr == NULL, "pre-condition");
351 }
352 G1CollectedHeap* g1h = G1CollectedHeap::heap();
353
354 // If we're within a stop-world GC, then we might look at a card in a
355 // GC alloc region that extends onto a GC LAB, which may not be
356 // parseable. Stop such at the "scan_top" of the region.
357 if (g1h->is_gc_active()) {
358 mr = mr.intersection(MemRegion(bottom(), scan_top()));
359 } else {
360 mr = mr.intersection(used_region());
361 }
362 if (mr.is_empty()) return NULL;
363 // Otherwise, find the obj that extends onto mr.start().
364
365 // The intersection of the incoming mr (for the card) and the
366 // allocated part of the region is non-empty. This implies that
367 // we have actually allocated into this region. The code in
368 // G1CollectedHeap.cpp that allocates a new region sets the
369 // is_young tag on the region before allocating. Thus we
370 // safely know if this region is young.
371 if (is_young() && filter_young) {
372 return NULL;
373 }
374
375 assert(!is_young(), "check value of filter_young");
376
377 // We can only clean the card here, after we make the decision that
378 // the card is not young. And we only clean the card if we have been
379 // asked to (i.e., card_ptr != NULL).
380 if (card_ptr != NULL) {
381 *card_ptr = CardTableModRefBS::clean_card_val();
382 // We must complete this write before we do any of the reads below.
383 OrderAccess::storeload();
384 }
385
386 // Cache the boundaries of the memory region in some const locals
387 HeapWord* const start = mr.start();
388 HeapWord* const end = mr.end();
389
390 // We used to use "block_start_careful" here. But we're actually happy
391 // to update the BOT while we do this...
392 HeapWord* cur = block_start(start);
393 assert(cur <= start, "Postcondition");
394
395 oop obj;
396
397 HeapWord* next = cur;
398 do {
399 cur = next;
400 obj = oop(cur);
401 if (obj->klass_or_null() == NULL) {
402 // Ran into an unparseable point.
403 return cur;
404 }
405 // Otherwise...
406 next = cur + block_size(cur);
407 } while (next <= start);
408
409 // If we finish the above loop...We have a parseable object that
410 // begins on or before the start of the memory region, and ends
411 // inside or spans the entire region.
412 assert(cur <= start, "Loop postcondition");
413 assert(obj->klass_or_null() != NULL, "Loop postcondition");
414
415 do {
416 obj = oop(cur);
417 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant");
418 if (obj->klass_or_null() == NULL) {
419 // Ran into an unparseable point.
420 return cur;
421 }
422
423 // Advance the current pointer. "obj" still points to the object to iterate.
424 cur = cur + block_size(cur);
425
426 if (!g1h->is_obj_dead(obj)) {
427 // Non-objArrays are sometimes marked imprecise at the object start. We
428 // always need to iterate over them in full.
429 // We only iterate over object arrays in full if they are completely contained
430 // in the memory region.
431 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) {
432 obj->oop_iterate(cl);
433 } else {
434 obj->oop_iterate(cl, mr);
435 }
436 }
437 } while (cur < end);
438
439 return NULL;
440 }
441
442 // Code roots support
443
444 void HeapRegion::add_strong_code_root(nmethod* nm) {
445 HeapRegionRemSet* hrrs = rem_set();
446 hrrs->add_strong_code_root(nm);
447 }
448
449 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
450 assert_locked_or_safepoint(CodeCache_lock);
451 HeapRegionRemSet* hrrs = rem_set();
452 hrrs->add_strong_code_root_locked(nm);
453 }
454
455 void HeapRegion::remove_strong_code_root(nmethod* nm) {
456 HeapRegionRemSet* hrrs = rem_set();
457 hrrs->remove_strong_code_root(nm);
458 }
459
460 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
461 HeapRegionRemSet* hrrs = rem_set();
462 hrrs->strong_code_roots_do(blk);
463 }
464
465 class VerifyStrongCodeRootOopClosure: public OopClosure {
466 const HeapRegion* _hr;
467 nmethod* _nm;
468 bool _failures;
469 bool _has_oops_in_region;
470
471 template <class T> void do_oop_work(T* p) {
472 T heap_oop = oopDesc::load_heap_oop(p);
473 if (!oopDesc::is_null(heap_oop)) {
474 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
475
476 // Note: not all the oops embedded in the nmethod are in the
477 // current region. We only look at those which are.
478 if (_hr->is_in(obj)) {
479 // Object is in the region. Check that its less than top
480 if (_hr->top() <= (HeapWord*)obj) {
481 // Object is above top
482 log_info(gc, verify)("Object " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ") is above top " PTR_FORMAT,
483 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top()));
484 _failures = true;
485 return;
486 }
487 // Nmethod has at least one oop in the current region
488 _has_oops_in_region = true;
489 }
490 }
491 }
492
493 public:
494 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
495 _hr(hr), _failures(false), _has_oops_in_region(false) {}
496
497 void do_oop(narrowOop* p) { do_oop_work(p); }
498 void do_oop(oop* p) { do_oop_work(p); }
499
500 bool failures() { return _failures; }
501 bool has_oops_in_region() { return _has_oops_in_region; }
502 };
503
504 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
505 const HeapRegion* _hr;
506 bool _failures;
507 public:
508 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
509 _hr(hr), _failures(false) {}
510
511 void do_code_blob(CodeBlob* cb) {
512 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
513 if (nm != NULL) {
514 // Verify that the nemthod is live
515 if (!nm->is_alive()) {
516 log_info(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " PTR_FORMAT " in its strong code roots",
517 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
518 _failures = true;
519 } else {
520 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
521 nm->oops_do(&oop_cl);
522 if (!oop_cl.has_oops_in_region()) {
523 log_info(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " PTR_FORMAT " in its strong code roots with no pointers into region",
524 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
525 _failures = true;
526 } else if (oop_cl.failures()) {
527 log_info(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has other failures for nmethod " PTR_FORMAT,
528 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
529 _failures = true;
530 }
531 }
532 }
533 }
534
535 bool failures() { return _failures; }
536 };
537
538 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
539 if (!G1VerifyHeapRegionCodeRoots) {
540 // We're not verifying code roots.
541 return;
542 }
543 if (vo == VerifyOption_G1UseMarkWord) {
544 // Marking verification during a full GC is performed after class
545 // unloading, code cache unloading, etc so the strong code roots
546 // attached to each heap region are in an inconsistent state. They won't
547 // be consistent until the strong code roots are rebuilt after the
548 // actual GC. Skip verifying the strong code roots in this particular
549 // time.
550 assert(VerifyDuringGC, "only way to get here");
551 return;
552 }
553
554 HeapRegionRemSet* hrrs = rem_set();
555 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
556
557 // if this region is empty then there should be no entries
558 // on its strong code root list
559 if (is_empty()) {
560 if (strong_code_roots_length > 0) {
561 log_info(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] is empty but has " SIZE_FORMAT " code root entries",
562 p2i(bottom()), p2i(end()), strong_code_roots_length);
563 *failures = true;
564 }
565 return;
566 }
567
568 if (is_continues_humongous()) {
569 if (strong_code_roots_length > 0) {
570 log_info(gc, verify)("region " HR_FORMAT " is a continuation of a humongous region but has " SIZE_FORMAT " code root entries",
571 HR_FORMAT_PARAMS(this), strong_code_roots_length);
572 *failures = true;
573 }
574 return;
575 }
576
577 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
578 strong_code_roots_do(&cb_cl);
579
580 if (cb_cl.failures()) {
581 *failures = true;
582 }
583 }
584
585 void HeapRegion::print() const { print_on(tty); }
586 void HeapRegion::print_on(outputStream* st) const {
587 st->print("|%4u", this->_hrm_index);
588 st->print("|" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT,
589 p2i(bottom()), p2i(top()), p2i(end()));
590 st->print("|%3d%%", (int) ((double) used() * 100 / capacity()));
591 st->print("|%2s", get_short_type_str());
592 if (in_collection_set()) {
593 st->print("|CS");
594 } else {
595 st->print("| ");
596 }
597 st->print("|TS%3u", _gc_time_stamp);
598 st->print("|AC%3u", allocation_context());
599 st->print_cr("|TAMS " PTR_FORMAT ", " PTR_FORMAT "|",
600 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start()));
601 }
602
603 class VerifyLiveClosure: public OopClosure {
604 private:
605 G1CollectedHeap* _g1h;
606 CardTableModRefBS* _bs;
607 oop _containing_obj;
608 bool _failures;
609 int _n_failures;
610 VerifyOption _vo;
611 public:
612 // _vo == UsePrevMarking -> use "prev" marking information,
613 // _vo == UseNextMarking -> use "next" marking information,
614 // _vo == UseMarkWord -> use mark word from object header.
615 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) :
616 _g1h(g1h), _bs(barrier_set_cast<CardTableModRefBS>(g1h->barrier_set())),
617 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo)
618 { }
619
620 void set_containing_obj(oop obj) {
621 _containing_obj = obj;
622 }
623
624 bool failures() { return _failures; }
625 int n_failures() { return _n_failures; }
626
627 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
628 virtual void do_oop( oop* p) { do_oop_work(p); }
629
630 void print_object(outputStream* out, oop obj) {
631 #ifdef PRODUCT
632 Klass* k = obj->klass();
633 const char* class_name = k->external_name();
634 out->print_cr("class name %s", class_name);
635 #else // PRODUCT
636 obj->print_on(out);
637 #endif // PRODUCT
638 }
639
640 template <class T>
641 void do_oop_work(T* p) {
642 assert(_containing_obj != NULL, "Precondition");
643 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
644 "Precondition");
645 T heap_oop = oopDesc::load_heap_oop(p);
646 LogHandle(gc, verify) log;
647 if (!oopDesc::is_null(heap_oop)) {
648 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
649 bool failed = false;
650 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
651 MutexLockerEx x(ParGCRareEvent_lock,
652 Mutex::_no_safepoint_check_flag);
653
654 if (!_failures) {
655 log.info("----------");
656 }
657 ResourceMark rm;
658 if (!_g1h->is_in_closed_subset(obj)) {
659 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
660 log.info("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
661 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
662 print_object(log.info_stream(), _containing_obj);
663 log.info("points to obj " PTR_FORMAT " not in the heap", p2i(obj));
664 } else {
665 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
666 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
667 log.info("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
668 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
669 print_object(log.info_stream(), _containing_obj);
670 log.info("points to dead obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
671 p2i(obj), p2i(to->bottom()), p2i(to->end()));
672 print_object(log.info_stream(), obj);
673 }
674 log.info("----------");
675 _failures = true;
676 failed = true;
677 _n_failures++;
678 }
679
680 if (!_g1h->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) {
681 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
682 HeapRegion* to = _g1h->heap_region_containing(obj);
683 if (from != NULL && to != NULL &&
684 from != to &&
685 !to->is_pinned()) {
686 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
687 jbyte cv_field = *_bs->byte_for_const(p);
688 const jbyte dirty = CardTableModRefBS::dirty_card_val();
689
690 bool is_bad = !(from->is_young()
691 || to->rem_set()->contains_reference(p)
692 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
693 (_containing_obj->is_objArray() ?
694 cv_field == dirty
695 : cv_obj == dirty || cv_field == dirty));
696 if (is_bad) {
697 MutexLockerEx x(ParGCRareEvent_lock,
698 Mutex::_no_safepoint_check_flag);
699
700 if (!_failures) {
701 log.info("----------");
702 }
703 log.info("Missing rem set entry:");
704 log.info("Field " PTR_FORMAT " of obj " PTR_FORMAT ", in region " HR_FORMAT,
705 p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
706 ResourceMark rm;
707 _containing_obj->print_on(log.info_stream());
708 log.info("points to obj " PTR_FORMAT " in region " HR_FORMAT, p2i(obj), HR_FORMAT_PARAMS(to));
709 obj->print_on(log.info_stream());
710 log.info("Obj head CTE = %d, field CTE = %d.", cv_obj, cv_field);
711 log.info("----------");
712 _failures = true;
713 if (!failed) _n_failures++;
714 }
715 }
716 }
717 }
718 }
719 };
720
721 // This really ought to be commoned up into OffsetTableContigSpace somehow.
722 // We would need a mechanism to make that code skip dead objects.
723
724 void HeapRegion::verify(VerifyOption vo,
725 bool* failures) const {
726 G1CollectedHeap* g1 = G1CollectedHeap::heap();
727 *failures = false;
728 HeapWord* p = bottom();
729 HeapWord* prev_p = NULL;
730 VerifyLiveClosure vl_cl(g1, vo);
731 bool is_region_humongous = is_humongous();
732 size_t object_num = 0;
733 while (p < top()) {
734 oop obj = oop(p);
735 size_t obj_size = block_size(p);
736 object_num += 1;
737
738 if (!g1->is_obj_dead_cond(obj, this, vo)) {
739 if (obj->is_oop()) {
740 Klass* klass = obj->klass();
741 bool is_metaspace_object = Metaspace::contains(klass) ||
742 (vo == VerifyOption_G1UsePrevMarking &&
743 ClassLoaderDataGraph::unload_list_contains(klass));
744 if (!is_metaspace_object) {
745 log_info(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
746 "not metadata", p2i(klass), p2i(obj));
747 *failures = true;
748 return;
749 } else if (!klass->is_klass()) {
750 log_info(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
751 "not a klass", p2i(klass), p2i(obj));
752 *failures = true;
753 return;
754 } else {
755 vl_cl.set_containing_obj(obj);
756 obj->oop_iterate_no_header(&vl_cl);
757 if (vl_cl.failures()) {
758 *failures = true;
759 }
760 if (G1MaxVerifyFailures >= 0 &&
761 vl_cl.n_failures() >= G1MaxVerifyFailures) {
762 return;
763 }
764 }
765 } else {
766 log_info(gc, verify)(PTR_FORMAT " no an oop", p2i(obj));
767 *failures = true;
768 return;
769 }
770 }
771 prev_p = p;
772 p += obj_size;
773 }
774
775 if (!is_young() && !is_empty()) {
776 _offsets.verify();
777 }
778
779 if (is_region_humongous) {
780 oop obj = oop(this->humongous_start_region()->bottom());
781 if ((HeapWord*)obj > bottom() || (HeapWord*)obj + obj->size() < bottom()) {
782 log_info(gc, verify)("this humongous region is not part of its' humongous object " PTR_FORMAT, p2i(obj));
783 }
784 }
785
786 if (!is_region_humongous && p != top()) {
787 log_info(gc, verify)("end of last object " PTR_FORMAT " "
788 "does not match top " PTR_FORMAT, p2i(p), p2i(top()));
789 *failures = true;
790 return;
791 }
792
793 HeapWord* the_end = end();
794 // Do some extra BOT consistency checking for addresses in the
795 // range [top, end). BOT look-ups in this range should yield
796 // top. No point in doing that if top == end (there's nothing there).
797 if (p < the_end) {
798 // Look up top
799 HeapWord* addr_1 = p;
800 HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
801 if (b_start_1 != p) {
802 log_info(gc, verify)("BOT look up for top: " PTR_FORMAT " "
803 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
804 p2i(addr_1), p2i(b_start_1), p2i(p));
805 *failures = true;
806 return;
807 }
808
809 // Look up top + 1
810 HeapWord* addr_2 = p + 1;
811 if (addr_2 < the_end) {
812 HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
813 if (b_start_2 != p) {
814 log_info(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " "
815 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
816 p2i(addr_2), p2i(b_start_2), p2i(p));
817 *failures = true;
818 return;
819 }
820 }
821
822 // Look up an address between top and end
823 size_t diff = pointer_delta(the_end, p) / 2;
824 HeapWord* addr_3 = p + diff;
825 if (addr_3 < the_end) {
826 HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
827 if (b_start_3 != p) {
828 log_info(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " "
829 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
830 p2i(addr_3), p2i(b_start_3), p2i(p));
831 *failures = true;
832 return;
833 }
834 }
835
836 // Look up end - 1
837 HeapWord* addr_4 = the_end - 1;
838 HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
839 if (b_start_4 != p) {
840 log_info(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " "
841 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
842 p2i(addr_4), p2i(b_start_4), p2i(p));
843 *failures = true;
844 return;
845 }
846 }
847
848 verify_strong_code_roots(vo, failures);
849 }
850
851 void HeapRegion::verify() const {
852 bool dummy = false;
853 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
854 }
855
856 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
857 scan_and_forward(this, cp);
858 }
859
860 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
861 // away eventually.
862
863 void G1OffsetTableContigSpace::clear(bool mangle_space) {
864 set_top(bottom());
865 _scan_top = bottom();
866 CompactibleSpace::clear(mangle_space);
867 reset_bot();
868 }
869
870 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
871 Space::set_bottom(new_bottom);
872 _offsets.set_bottom(new_bottom);
873 }
874
875 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
876 assert(new_end == _bottom + HeapRegion::GrainWords, "set_end should only ever be set to _bottom + HeapRegion::GrainWords");
877 Space::set_end(new_end);
878 _offsets.resize(new_end - bottom());
879 }
880
881 #ifndef PRODUCT
882 void G1OffsetTableContigSpace::mangle_unused_area() {
883 mangle_unused_area_complete();
884 }
885
886 void G1OffsetTableContigSpace::mangle_unused_area_complete() {
887 SpaceMangler::mangle_region(MemRegion(top(), end()));
888 }
889 #endif
890
891 void G1OffsetTableContigSpace::print() const {
892 print_short();
893 tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
894 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
895 p2i(bottom()), p2i(top()), p2i(_offsets.threshold()), p2i(end()));
896 }
897
898 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
899 return _offsets.initialize_threshold();
900 }
901
902 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
903 HeapWord* end) {
904 _offsets.alloc_block(start, end);
905 return _offsets.threshold();
906 }
907
908 HeapWord* G1OffsetTableContigSpace::scan_top() const {
909 G1CollectedHeap* g1h = G1CollectedHeap::heap();
910 HeapWord* local_top = top();
911 OrderAccess::loadload();
912 const unsigned local_time_stamp = _gc_time_stamp;
913 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
914 if (local_time_stamp < g1h->get_gc_time_stamp()) {
915 return local_top;
916 } else {
917 return _scan_top;
918 }
919 }
920
921 void G1OffsetTableContigSpace::record_timestamp() {
922 G1CollectedHeap* g1h = G1CollectedHeap::heap();
923 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
924
925 if (_gc_time_stamp < curr_gc_time_stamp) {
926 // Setting the time stamp here tells concurrent readers to look at
927 // scan_top to know the maximum allowed address to look at.
928
929 // scan_top should be bottom for all regions except for the
930 // retained old alloc region which should have scan_top == top
931 HeapWord* st = _scan_top;
932 guarantee(st == _bottom || st == _top, "invariant");
933
934 _gc_time_stamp = curr_gc_time_stamp;
935 }
936 }
937
938 void G1OffsetTableContigSpace::record_retained_region() {
939 // scan_top is the maximum address where it's safe for the next gc to
940 // scan this region.
941 _scan_top = top();
942 }
943
944 void G1OffsetTableContigSpace::safe_object_iterate(ObjectClosure* blk) {
945 object_iterate(blk);
946 }
947
948 void G1OffsetTableContigSpace::object_iterate(ObjectClosure* blk) {
949 HeapWord* p = bottom();
950 while (p < top()) {
951 if (block_is_obj(p)) {
952 blk->do_object(oop(p));
953 }
954 p += block_size(p);
955 }
956 }
957
958 G1OffsetTableContigSpace::
959 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
960 MemRegion mr) :
961 _offsets(sharedOffsetArray, mr),
962 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
963 _gc_time_stamp(0)
964 {
965 _offsets.set_space(this);
966 }
967
968 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
969 CompactibleSpace::initialize(mr, clear_space, mangle_space);
970 _top = bottom();
971 _scan_top = bottom();
972 set_saved_mark_word(NULL);
973 reset_bot();
974 }
975