1 /*
2 * Copyright (c) 2001, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "code/nmethod.hpp"
27 #include "gc/g1/g1BlockOffsetTable.inline.hpp"
28 #include "gc/g1/g1CollectedHeap.inline.hpp"
29 #include "gc/g1/g1OopClosures.inline.hpp"
30 #include "gc/g1/heapRegion.inline.hpp"
31 #include "gc/g1/heapRegionBounds.inline.hpp"
32 #include "gc/g1/heapRegionManager.inline.hpp"
33 #include "gc/g1/heapRegionRemSet.hpp"
34 #include "gc/shared/genOopClosures.inline.hpp"
35 #include "gc/shared/liveRange.hpp"
36 #include "gc/shared/space.inline.hpp"
37 #include "memory/iterator.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "runtime/atomic.inline.hpp"
40 #include "runtime/orderAccess.inline.hpp"
41
42 int HeapRegion::LogOfHRGrainBytes = 0;
43 int HeapRegion::LogOfHRGrainWords = 0;
44 size_t HeapRegion::GrainBytes = 0;
45 size_t HeapRegion::GrainWords = 0;
46 size_t HeapRegion::CardsPerRegion = 0;
47
48 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
49 HeapRegion* hr,
50 G1ParPushHeapRSClosure* cl,
51 CardTableModRefBS::PrecisionStyle precision) :
52 DirtyCardToOopClosure(hr, cl, precision, NULL),
53 _hr(hr), _rs_scan(cl), _g1(g1) { }
54
55 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
56 OopClosure* oc) :
57 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
58
59 void HeapRegionDCTOC::walk_mem_region(MemRegion mr,
60 HeapWord* bottom,
61 HeapWord* top) {
62 G1CollectedHeap* g1h = _g1;
63 size_t oop_size;
64 HeapWord* cur = bottom;
65
66 // Start filtering what we add to the remembered set. If the object is
67 // not considered dead, either because it is marked (in the mark bitmap)
68 // or it was allocated after marking finished, then we add it. Otherwise
69 // we can safely ignore the object.
70 if (!g1h->is_obj_dead(oop(cur))) {
71 oop_size = oop(cur)->oop_iterate_size(_rs_scan, mr);
72 } else {
73 oop_size = _hr->block_size(cur);
74 }
75
76 cur += oop_size;
77
78 if (cur < top) {
79 oop cur_oop = oop(cur);
80 oop_size = _hr->block_size(cur);
81 HeapWord* next_obj = cur + oop_size;
82 while (next_obj < top) {
83 // Keep filtering the remembered set.
84 if (!g1h->is_obj_dead(cur_oop)) {
85 // Bottom lies entirely below top, so we can call the
86 // non-memRegion version of oop_iterate below.
87 cur_oop->oop_iterate(_rs_scan);
88 }
89 cur = next_obj;
90 cur_oop = oop(cur);
91 oop_size = _hr->block_size(cur);
92 next_obj = cur + oop_size;
93 }
94
95 // Last object. Need to do dead-obj filtering here too.
96 if (!g1h->is_obj_dead(oop(cur))) {
97 oop(cur)->oop_iterate(_rs_scan, mr);
98 }
99 }
100 }
101
102 size_t HeapRegion::max_region_size() {
103 return HeapRegionBounds::max_size();
104 }
105
106 size_t HeapRegion::min_region_size_in_words() {
107 return HeapRegionBounds::min_size() >> LogHeapWordSize;
108 }
109
110 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
111 size_t region_size = G1HeapRegionSize;
112 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
113 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
114 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(),
115 HeapRegionBounds::min_size());
116 }
117
118 int region_size_log = log2_long((jlong) region_size);
119 // Recalculate the region size to make sure it's a power of
120 // 2. This means that region_size is the largest power of 2 that's
121 // <= what we've calculated so far.
122 region_size = ((size_t)1 << region_size_log);
123
124 // Now make sure that we don't go over or under our limits.
125 if (region_size < HeapRegionBounds::min_size()) {
126 region_size = HeapRegionBounds::min_size();
127 } else if (region_size > HeapRegionBounds::max_size()) {
128 region_size = HeapRegionBounds::max_size();
129 }
130
131 // And recalculate the log.
132 region_size_log = log2_long((jlong) region_size);
133
134 // Now, set up the globals.
135 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
136 LogOfHRGrainBytes = region_size_log;
137
138 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
139 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
140
141 guarantee(GrainBytes == 0, "we should only set it once");
142 // The cast to int is safe, given that we've bounded region_size by
143 // MIN_REGION_SIZE and MAX_REGION_SIZE.
144 GrainBytes = region_size;
145
146 guarantee(GrainWords == 0, "we should only set it once");
147 GrainWords = GrainBytes >> LogHeapWordSize;
148 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
149
150 guarantee(CardsPerRegion == 0, "we should only set it once");
151 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
152 }
153
154 void HeapRegion::reset_after_compaction() {
155 G1OffsetTableContigSpace::reset_after_compaction();
156 // After a compaction the mark bitmap is invalid, so we must
157 // treat all objects as being inside the unmarked area.
158 zero_marked_bytes();
159 init_top_at_mark_start();
160 }
161
162 void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
163 assert(_humongous_start_region == NULL,
164 "we should have already filtered out humongous regions");
165 assert(!in_collection_set(),
166 "Should not clear heap region %u in the collection set", hrm_index());
167
168 set_allocation_context(AllocationContext::system());
169 set_young_index_in_cset(-1);
170 uninstall_surv_rate_group();
171 set_free();
172 reset_pre_dummy_top();
173
174 if (!par) {
175 // If this is parallel, this will be done later.
176 HeapRegionRemSet* hrrs = rem_set();
177 if (locked) {
178 hrrs->clear_locked();
179 } else {
180 hrrs->clear();
181 }
182 }
183 zero_marked_bytes();
184
185 _offsets.resize(HeapRegion::GrainWords);
186 init_top_at_mark_start();
187 if (clear_space) clear(SpaceDecorator::Mangle);
188 }
189
190 void HeapRegion::par_clear() {
191 assert(used() == 0, "the region should have been already cleared");
192 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
193 HeapRegionRemSet* hrrs = rem_set();
194 hrrs->clear();
195 CardTableModRefBS* ct_bs =
196 barrier_set_cast<CardTableModRefBS>(G1CollectedHeap::heap()->barrier_set());
197 ct_bs->clear(MemRegion(bottom(), end()));
198 }
199
200 void HeapRegion::calc_gc_efficiency() {
201 // GC efficiency is the ratio of how much space would be
202 // reclaimed over how long we predict it would take to reclaim it.
203 G1CollectedHeap* g1h = G1CollectedHeap::heap();
204 G1CollectorPolicy* g1p = g1h->g1_policy();
205
206 // Retrieve a prediction of the elapsed time for this region for
207 // a mixed gc because the region will only be evacuated during a
208 // mixed gc.
209 double region_elapsed_time_ms =
210 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
211 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
212 }
213
214 void HeapRegion::set_starts_humongous(HeapWord* obj_top, size_t fill_size) {
215 assert(!is_humongous(), "sanity / pre-condition");
216 assert(top() == bottom(), "should be empty");
217
218 _type.set_starts_humongous();
219 _humongous_start_region = this;
220
221 _offsets.set_for_starts_humongous(obj_top, fill_size);
222 }
223
224 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) {
225 assert(!is_humongous(), "sanity / pre-condition");
226 assert(top() == bottom(), "should be empty");
227 assert(first_hr->is_starts_humongous(), "pre-condition");
228
229 _type.set_continues_humongous();
230 _humongous_start_region = first_hr;
231 }
232
233 void HeapRegion::clear_humongous() {
234 assert(is_humongous(), "pre-condition");
235
236 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
237 _humongous_start_region = NULL;
238 }
239
240 HeapRegion::HeapRegion(uint hrm_index,
241 G1BlockOffsetSharedArray* sharedOffsetArray,
242 MemRegion mr) :
243 G1OffsetTableContigSpace(sharedOffsetArray, mr),
244 _hrm_index(hrm_index),
245 _allocation_context(AllocationContext::system()),
246 _humongous_start_region(NULL),
247 _next_in_special_set(NULL),
248 _evacuation_failed(false),
249 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
250 _next_young_region(NULL),
251 _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL),
252 #ifdef ASSERT
253 _containing_set(NULL),
254 #endif // ASSERT
255 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
256 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
257 _predicted_bytes_to_copy(0)
258 {
259 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
260 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
261
262 initialize(mr);
263 }
264
265 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
266 assert(_rem_set->is_empty(), "Remembered set must be empty");
267
268 G1OffsetTableContigSpace::initialize(mr, clear_space, mangle_space);
269
270 hr_clear(false /*par*/, false /*clear_space*/);
271 set_top(bottom());
272 record_timestamp();
273 }
274
275 CompactibleSpace* HeapRegion::next_compaction_space() const {
276 return G1CollectedHeap::heap()->next_compaction_region(this);
277 }
278
279 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
280 bool during_conc_mark) {
281 // We always recreate the prev marking info and we'll explicitly
282 // mark all objects we find to be self-forwarded on the prev
283 // bitmap. So all objects need to be below PTAMS.
284 _prev_marked_bytes = 0;
285
286 if (during_initial_mark) {
287 // During initial-mark, we'll also explicitly mark all objects
288 // we find to be self-forwarded on the next bitmap. So all
289 // objects need to be below NTAMS.
290 _next_top_at_mark_start = top();
291 _next_marked_bytes = 0;
292 } else if (during_conc_mark) {
293 // During concurrent mark, all objects in the CSet (including
294 // the ones we find to be self-forwarded) are implicitly live.
295 // So all objects need to be above NTAMS.
296 _next_top_at_mark_start = bottom();
297 _next_marked_bytes = 0;
298 }
299 }
300
301 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
302 bool during_conc_mark,
303 size_t marked_bytes) {
304 assert(marked_bytes <= used(),
305 "marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used());
306 _prev_top_at_mark_start = top();
307 _prev_marked_bytes = marked_bytes;
308 }
309
310 HeapWord*
311 HeapRegion::object_iterate_mem_careful(MemRegion mr,
312 ObjectClosure* cl) {
313 G1CollectedHeap* g1h = G1CollectedHeap::heap();
314 // We used to use "block_start_careful" here. But we're actually happy
315 // to update the BOT while we do this...
316 HeapWord* cur = block_start(mr.start());
317 mr = mr.intersection(used_region());
318 if (mr.is_empty()) return NULL;
319 // Otherwise, find the obj that extends onto mr.start().
320
321 assert(cur <= mr.start()
322 && (oop(cur)->klass_or_null() == NULL ||
323 cur + oop(cur)->size() > mr.start()),
324 "postcondition of block_start");
325 oop obj;
326 while (cur < mr.end()) {
327 obj = oop(cur);
328 if (obj->klass_or_null() == NULL) {
329 // Ran into an unparseable point.
330 return cur;
331 } else if (!g1h->is_obj_dead(obj)) {
332 cl->do_object(obj);
333 }
334 cur += block_size(cur);
335 }
336 return NULL;
337 }
338
339 HeapWord*
340 HeapRegion::
341 oops_on_card_seq_iterate_careful(MemRegion mr,
342 FilterOutOfRegionClosure* cl,
343 bool filter_young,
344 jbyte* card_ptr) {
345 // Currently, we should only have to clean the card if filter_young
346 // is true and vice versa.
347 if (filter_young) {
348 assert(card_ptr != NULL, "pre-condition");
349 } else {
350 assert(card_ptr == NULL, "pre-condition");
351 }
352 G1CollectedHeap* g1h = G1CollectedHeap::heap();
353
354 // If we're within a stop-world GC, then we might look at a card in a
355 // GC alloc region that extends onto a GC LAB, which may not be
356 // parseable. Stop such at the "scan_top" of the region.
357 if (g1h->is_gc_active()) {
358 mr = mr.intersection(MemRegion(bottom(), scan_top()));
359 } else {
360 mr = mr.intersection(used_region());
361 }
362 if (mr.is_empty()) return NULL;
363 // Otherwise, find the obj that extends onto mr.start().
364
365 // The intersection of the incoming mr (for the card) and the
366 // allocated part of the region is non-empty. This implies that
367 // we have actually allocated into this region. The code in
368 // G1CollectedHeap.cpp that allocates a new region sets the
369 // is_young tag on the region before allocating. Thus we
370 // safely know if this region is young.
371 if (is_young() && filter_young) {
372 return NULL;
373 }
374
375 assert(!is_young(), "check value of filter_young");
376
377 // We can only clean the card here, after we make the decision that
378 // the card is not young. And we only clean the card if we have been
379 // asked to (i.e., card_ptr != NULL).
380 if (card_ptr != NULL) {
381 *card_ptr = CardTableModRefBS::clean_card_val();
382 // We must complete this write before we do any of the reads below.
383 OrderAccess::storeload();
384 }
385
386 // Cache the boundaries of the memory region in some const locals
387 HeapWord* const start = mr.start();
388 HeapWord* const end = mr.end();
389
390 // We used to use "block_start_careful" here. But we're actually happy
391 // to update the BOT while we do this...
392 HeapWord* cur = block_start(start);
393 assert(cur <= start, "Postcondition");
394
395 oop obj;
396
397 HeapWord* next = cur;
398 do {
399 cur = next;
400 obj = oop(cur);
401 if (obj->klass_or_null() == NULL) {
402 // Ran into an unparseable point.
403 return cur;
404 }
405 // Otherwise...
406 next = cur + block_size(cur);
407 } while (next <= start);
408
409 // If we finish the above loop...We have a parseable object that
410 // begins on or before the start of the memory region, and ends
411 // inside or spans the entire region.
412 assert(cur <= start, "Loop postcondition");
413 assert(obj->klass_or_null() != NULL, "Loop postcondition");
414
415 do {
416 obj = oop(cur);
417 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant");
418 if (obj->klass_or_null() == NULL) {
419 // Ran into an unparseable point.
420 return cur;
421 }
422
423 // Advance the current pointer. "obj" still points to the object to iterate.
424 cur = cur + block_size(cur);
425
426 if (!g1h->is_obj_dead(obj)) {
427 // Non-objArrays are sometimes marked imprecise at the object start. We
428 // always need to iterate over them in full.
429 // We only iterate over object arrays in full if they are completely contained
430 // in the memory region.
431 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) {
432 obj->oop_iterate(cl);
433 } else {
434 obj->oop_iterate(cl, mr);
435 }
436 }
437 } while (cur < end);
438
439 return NULL;
440 }
441
442 // Code roots support
443
444 void HeapRegion::add_strong_code_root(nmethod* nm) {
445 HeapRegionRemSet* hrrs = rem_set();
446 hrrs->add_strong_code_root(nm);
447 }
448
449 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
450 assert_locked_or_safepoint(CodeCache_lock);
451 HeapRegionRemSet* hrrs = rem_set();
452 hrrs->add_strong_code_root_locked(nm);
453 }
454
455 void HeapRegion::remove_strong_code_root(nmethod* nm) {
456 HeapRegionRemSet* hrrs = rem_set();
457 hrrs->remove_strong_code_root(nm);
458 }
459
460 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
461 HeapRegionRemSet* hrrs = rem_set();
462 hrrs->strong_code_roots_do(blk);
463 }
464
465 class VerifyStrongCodeRootOopClosure: public OopClosure {
466 const HeapRegion* _hr;
467 nmethod* _nm;
468 bool _failures;
469 bool _has_oops_in_region;
470
471 template <class T> void do_oop_work(T* p) {
472 T heap_oop = oopDesc::load_heap_oop(p);
473 if (!oopDesc::is_null(heap_oop)) {
474 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
475
476 // Note: not all the oops embedded in the nmethod are in the
477 // current region. We only look at those which are.
478 if (_hr->is_in(obj)) {
479 // Object is in the region. Check that its less than top
480 if (_hr->top() <= (HeapWord*)obj) {
481 // Object is above top
482 gclog_or_tty->print_cr("Object " PTR_FORMAT " in region "
483 "[" PTR_FORMAT ", " PTR_FORMAT ") is above "
484 "top " PTR_FORMAT,
485 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top()));
486 _failures = true;
487 return;
488 }
489 // Nmethod has at least one oop in the current region
490 _has_oops_in_region = true;
491 }
492 }
493 }
494
495 public:
496 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
497 _hr(hr), _failures(false), _has_oops_in_region(false) {}
498
499 void do_oop(narrowOop* p) { do_oop_work(p); }
500 void do_oop(oop* p) { do_oop_work(p); }
501
502 bool failures() { return _failures; }
503 bool has_oops_in_region() { return _has_oops_in_region; }
504 };
505
506 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
507 const HeapRegion* _hr;
508 bool _failures;
509 public:
510 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
511 _hr(hr), _failures(false) {}
512
513 void do_code_blob(CodeBlob* cb) {
514 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
515 if (nm != NULL) {
516 // Verify that the nemthod is live
517 if (!nm->is_alive()) {
518 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod "
519 PTR_FORMAT " in its strong code roots",
520 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
521 _failures = true;
522 } else {
523 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
524 nm->oops_do(&oop_cl);
525 if (!oop_cl.has_oops_in_region()) {
526 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod "
527 PTR_FORMAT " in its strong code roots "
528 "with no pointers into region",
529 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
530 _failures = true;
531 } else if (oop_cl.failures()) {
532 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] has other "
533 "failures for nmethod " PTR_FORMAT,
534 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
535 _failures = true;
536 }
537 }
538 }
539 }
540
541 bool failures() { return _failures; }
542 };
543
544 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
545 if (!G1VerifyHeapRegionCodeRoots) {
546 // We're not verifying code roots.
547 return;
548 }
549 if (vo == VerifyOption_G1UseMarkWord) {
550 // Marking verification during a full GC is performed after class
551 // unloading, code cache unloading, etc so the strong code roots
552 // attached to each heap region are in an inconsistent state. They won't
553 // be consistent until the strong code roots are rebuilt after the
554 // actual GC. Skip verifying the strong code roots in this particular
555 // time.
556 assert(VerifyDuringGC, "only way to get here");
557 return;
558 }
559
560 HeapRegionRemSet* hrrs = rem_set();
561 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
562
563 // if this region is empty then there should be no entries
564 // on its strong code root list
565 if (is_empty()) {
566 if (strong_code_roots_length > 0) {
567 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] is empty "
568 "but has " SIZE_FORMAT " code root entries",
569 p2i(bottom()), p2i(end()), strong_code_roots_length);
570 *failures = true;
571 }
572 return;
573 }
574
575 if (is_continues_humongous()) {
576 if (strong_code_roots_length > 0) {
577 gclog_or_tty->print_cr("region " HR_FORMAT " is a continuation of a humongous "
578 "region but has " SIZE_FORMAT " code root entries",
579 HR_FORMAT_PARAMS(this), strong_code_roots_length);
580 *failures = true;
581 }
582 return;
583 }
584
585 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
586 strong_code_roots_do(&cb_cl);
587
588 if (cb_cl.failures()) {
589 *failures = true;
590 }
591 }
592
593 void HeapRegion::print() const { print_on(gclog_or_tty); }
594 void HeapRegion::print_on(outputStream* st) const {
595 st->print("AC%4u", allocation_context());
596
597 st->print(" %2s", get_short_type_str());
598 if (in_collection_set())
599 st->print(" CS");
600 else
601 st->print(" ");
602 st->print(" TS %5d", _gc_time_stamp);
603 st->print(" PTAMS " PTR_FORMAT " NTAMS " PTR_FORMAT,
604 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start()));
605 G1OffsetTableContigSpace::print_on(st);
606 }
607
608 class HeapRegionVerifyClosure : public OopClosure {
609 protected:
610 G1CollectedHeap* _g1h;
611 CardTableModRefBS* _bs;
612 oop _containing_obj;
613 bool _failures;
614 int _n_failures;
615 VerifyOption _vo;
616 public:
617 // _vo == UsePrevMarking -> use "prev" marking information,
618 // _vo == UseNextMarking -> use "next" marking information,
619 // _vo == UseMarkWord -> use mark word from object header.
620 HeapRegionVerifyClosure(G1CollectedHeap* g1h, VerifyOption vo) :
621 _g1h(g1h), _bs(barrier_set_cast<CardTableModRefBS>(g1h->barrier_set())),
622 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo)
623 { }
624
625 void set_containing_obj(oop obj) {
626 _containing_obj = obj;
627 }
628
629 bool failures() { return _failures; }
630 int n_failures() { return _n_failures; }
631
632 void print_object(outputStream* out, oop obj) {
633 #ifdef PRODUCT
634 Klass* k = obj->klass();
635 const char* class_name = k->external_name();
636 out->print_cr("class name %s", class_name);
637 #else // PRODUCT
638 obj->print_on(out);
639 #endif // PRODUCT
640 }
641
642 template <class T>
643 void verifyRemSets(T* p) {
644 T heap_oop = oopDesc::load_heap_oop(p);
645 if (!oopDesc::is_null(heap_oop)) {
646 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
647 bool failed = false;
648
649 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
650 HeapRegion* to = _g1h->heap_region_containing(obj);
651 if (from != NULL && to != NULL &&
652 from != to &&
653 !to->is_pinned()) {
654 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
655 jbyte cv_field = *_bs->byte_for_const(p);
656 const jbyte dirty = CardTableModRefBS::dirty_card_val();
657
658 bool is_bad = !(from->is_young()
659 || to->rem_set()->contains_reference(p)
660 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
661 (_containing_obj->is_objArray() ?
662 cv_field == dirty
663 : cv_obj == dirty || cv_field == dirty));
664 if (is_bad) {
665 MutexLockerEx x(ParGCRareEvent_lock,
666 Mutex::_no_safepoint_check_flag);
667
668 if (!_failures) {
669 gclog_or_tty->cr();
670 gclog_or_tty->print_cr("----------");
671 }
672 gclog_or_tty->print_cr("Missing rem set entry:");
673 gclog_or_tty->print_cr("Field " PTR_FORMAT " "
674 "of obj " PTR_FORMAT ", "
675 "in region " HR_FORMAT,
676 p2i(p), p2i(_containing_obj),
677 HR_FORMAT_PARAMS(from));
678 _containing_obj->print_on(gclog_or_tty);
679 gclog_or_tty->print_cr("points to obj " PTR_FORMAT " "
680 "in region " HR_FORMAT,
681 p2i(obj),
682 HR_FORMAT_PARAMS(to));
683 obj->print_on(gclog_or_tty);
684 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
685 cv_obj, cv_field);
686 gclog_or_tty->print_cr("----------");
687 gclog_or_tty->flush();
688 _failures = true;
689 if (!failed) _n_failures++;
690 }
691 }
692 }
693 }
694 };
695
696 class VerifyRSetClosure : public HeapRegionVerifyClosure {
697
698 public:
699 VerifyRSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : HeapRegionVerifyClosure(g1h, vo) { }
700
701 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
702 virtual void do_oop(oop* p) { do_oop_work(p); }
703
704 template <class T>
705 void do_oop_work(T* p) {
706 assert(_containing_obj != NULL, "Precondition");
707 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
708 "Precondition");
709
710 verifyRemSets(p);
711 }
712 };
713
714 class VerifyLiveClosure : public HeapRegionVerifyClosure {
715 public:
716 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : HeapRegionVerifyClosure(g1h, vo) { }
717
718 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
719 virtual void do_oop( oop* p) { do_oop_work(p); }
720
721 template <class T>
722 void do_oop_work(T* p) {
723 assert(_containing_obj != NULL, "Precondition");
724 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
725 "Precondition");
726 T heap_oop = oopDesc::load_heap_oop(p);
727 if (!oopDesc::is_null(heap_oop)) {
728 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
729 bool failed = false;
730 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
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 if (!_g1h->is_in_closed_subset(obj)) {
739 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
740 gclog_or_tty->print_cr("Field " PTR_FORMAT
741 " of live obj " PTR_FORMAT " in region "
742 "[" PTR_FORMAT ", " PTR_FORMAT ")",
743 p2i(p), p2i(_containing_obj),
744 p2i(from->bottom()), p2i(from->end()));
745 print_object(gclog_or_tty, _containing_obj);
746 gclog_or_tty->print_cr("points to obj " PTR_FORMAT " not in the heap",
747 p2i(obj));
748 } else {
749 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
750 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
751 gclog_or_tty->print_cr("Field " PTR_FORMAT
752 " of live obj " PTR_FORMAT " in region "
753 "[" PTR_FORMAT ", " PTR_FORMAT ")",
754 p2i(p), p2i(_containing_obj),
755 p2i(from->bottom()), p2i(from->end()));
756 print_object(gclog_or_tty, _containing_obj);
757 gclog_or_tty->print_cr("points to dead obj " PTR_FORMAT " in region "
758 "[" PTR_FORMAT ", " PTR_FORMAT ")",
759 p2i(obj), p2i(to->bottom()), p2i(to->end()));
760 print_object(gclog_or_tty, obj);
761 }
762 gclog_or_tty->print_cr("----------");
763 gclog_or_tty->flush();
764 _failures = true;
765 failed = true;
766 _n_failures++;
767 }
768
769 if (!_g1h->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) {
770 verifyRemSets(p);
771 }
772 }
773 }
774 };
775
776 // This really ought to be commoned up into OffsetTableContigSpace somehow.
777 // We would need a mechanism to make that code skip dead objects.
778
779 void HeapRegion::verify(VerifyOption vo,
780 bool* failures) const {
781 G1CollectedHeap* g1 = G1CollectedHeap::heap();
782 *failures = false;
783 HeapWord* p = bottom();
784 HeapWord* prev_p = NULL;
785 VerifyLiveClosure vl_cl(g1, vo);
786 bool is_region_humongous = is_humongous();
787 size_t object_num = 0;
788 while (p < top()) {
789 oop obj = oop(p);
790 size_t obj_size = block_size(p);
791 object_num += 1;
792
793 if (!g1->is_obj_dead_cond(obj, this, vo)) {
794 if (obj->is_oop()) {
795 Klass* klass = obj->klass();
796 bool is_metaspace_object = Metaspace::contains(klass) ||
797 (vo == VerifyOption_G1UsePrevMarking &&
798 ClassLoaderDataGraph::unload_list_contains(klass));
799 if (!is_metaspace_object) {
800 gclog_or_tty->print_cr("klass " PTR_FORMAT " of object " PTR_FORMAT " "
801 "not metadata", p2i(klass), p2i(obj));
802 *failures = true;
803 return;
804 } else if (!klass->is_klass()) {
805 gclog_or_tty->print_cr("klass " PTR_FORMAT " of object " PTR_FORMAT " "
806 "not a klass", p2i(klass), p2i(obj));
807 *failures = true;
808 return;
809 } else {
810 vl_cl.set_containing_obj(obj);
811 obj->oop_iterate_no_header(&vl_cl);
812 if (vl_cl.failures()) {
813 *failures = true;
814 }
815 if (G1MaxVerifyFailures >= 0 &&
816 vl_cl.n_failures() >= G1MaxVerifyFailures) {
817 return;
818 }
819 }
820 } else {
821 gclog_or_tty->print_cr(PTR_FORMAT " no an oop", p2i(obj));
822 *failures = true;
823 return;
824 }
825 }
826 prev_p = p;
827 p += obj_size;
828 }
829
830 if (!is_young() && !is_empty()) {
831 _offsets.verify();
832 }
833
834 if (is_region_humongous) {
835 oop obj = oop(this->humongous_start_region()->bottom());
836 if ((HeapWord*)obj > bottom() || (HeapWord*)obj + obj->size() < bottom()) {
837 gclog_or_tty->print_cr("this humongous region is not part of its' humongous object " PTR_FORMAT, p2i(obj));
838 }
839 }
840
841 if (!is_region_humongous && p != top()) {
842 gclog_or_tty->print_cr("end of last object " PTR_FORMAT " "
843 "does not match top " PTR_FORMAT, p2i(p), p2i(top()));
844 *failures = true;
845 return;
846 }
847
848 HeapWord* the_end = end();
849 // Do some extra BOT consistency checking for addresses in the
850 // range [top, end). BOT look-ups in this range should yield
851 // top. No point in doing that if top == end (there's nothing there).
852 if (p < the_end) {
853 // Look up top
854 HeapWord* addr_1 = p;
855 HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
856 if (b_start_1 != p) {
857 gclog_or_tty->print_cr("BOT look up for top: " PTR_FORMAT " "
858 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
859 p2i(addr_1), p2i(b_start_1), p2i(p));
860 *failures = true;
861 return;
862 }
863
864 // Look up top + 1
865 HeapWord* addr_2 = p + 1;
866 if (addr_2 < the_end) {
867 HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
868 if (b_start_2 != p) {
869 gclog_or_tty->print_cr("BOT look up for top + 1: " PTR_FORMAT " "
870 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
871 p2i(addr_2), p2i(b_start_2), p2i(p));
872 *failures = true;
873 return;
874 }
875 }
876
877 // Look up an address between top and end
878 size_t diff = pointer_delta(the_end, p) / 2;
879 HeapWord* addr_3 = p + diff;
880 if (addr_3 < the_end) {
881 HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
882 if (b_start_3 != p) {
883 gclog_or_tty->print_cr("BOT look up for top + diff: " PTR_FORMAT " "
884 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
885 p2i(addr_3), p2i(b_start_3), p2i(p));
886 *failures = true;
887 return;
888 }
889 }
890
891 // Look up end - 1
892 HeapWord* addr_4 = the_end - 1;
893 HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
894 if (b_start_4 != p) {
895 gclog_or_tty->print_cr("BOT look up for end - 1: " PTR_FORMAT " "
896 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
897 p2i(addr_4), p2i(b_start_4), p2i(p));
898 *failures = true;
899 return;
900 }
901 }
902
903 verify_strong_code_roots(vo, failures);
904 }
905
906 void HeapRegion::verify() const {
907 bool dummy = false;
908 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
909 }
910
911 void HeapRegion::verifyRSet(VerifyOption vo,
912 bool* failures) const {
913 G1CollectedHeap* g1 = G1CollectedHeap::heap();
914 *failures = false;
915 HeapWord* p = bottom();
916 HeapWord* prev_p = NULL;
917 VerifyRSetClosure v_rset_cl(g1, vo);
918 bool is_region_humongous = is_humongous();
919 while (p < top()) {
920 oop obj = oop(p);
921 size_t obj_size = block_size(p);
922
923 if (!g1->is_obj_dead_cond(obj, this, vo)) {
924 if (obj->is_oop()) {
925 v_rset_cl.set_containing_obj(obj);
926 obj->oop_iterate_no_header(&v_rset_cl);
927 if (v_rset_cl.failures()) {
928 *failures = true;
929 }
930 if (G1MaxVerifyFailures >= 0 &&
931 v_rset_cl.n_failures() >= G1MaxVerifyFailures) {
932 return;
933 }
934 }
935 else {
936 gclog_or_tty->print_cr(PTR_FORMAT " not an oop", p2i(obj));
937 *failures = true;
938 return;
939 }
940 }
941 prev_p = p;
942 p += obj_size;
943 }
944 }
945
946 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
947 scan_and_forward(this, cp);
948 }
949
950 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
951 // away eventually.
952
953 void G1OffsetTableContigSpace::clear(bool mangle_space) {
954 set_top(bottom());
955 _scan_top = bottom();
956 CompactibleSpace::clear(mangle_space);
957 reset_bot();
958 }
959
960 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
961 Space::set_bottom(new_bottom);
962 _offsets.set_bottom(new_bottom);
963 }
964
965 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
966 assert(new_end == _bottom + HeapRegion::GrainWords, "set_end should only ever be set to _bottom + HeapRegion::GrainWords");
967 Space::set_end(new_end);
968 _offsets.resize(new_end - bottom());
969 }
970
971 #ifndef PRODUCT
972 void G1OffsetTableContigSpace::mangle_unused_area() {
973 mangle_unused_area_complete();
974 }
975
976 void G1OffsetTableContigSpace::mangle_unused_area_complete() {
977 SpaceMangler::mangle_region(MemRegion(top(), end()));
978 }
979 #endif
980
981 void G1OffsetTableContigSpace::print() const {
982 print_short();
983 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
984 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
985 p2i(bottom()), p2i(top()), p2i(_offsets.threshold()), p2i(end()));
986 }
987
988 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
989 return _offsets.initialize_threshold();
990 }
991
992 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
993 HeapWord* end) {
994 _offsets.alloc_block(start, end);
995 return _offsets.threshold();
996 }
997
998 HeapWord* G1OffsetTableContigSpace::scan_top() const {
999 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1000 HeapWord* local_top = top();
1001 OrderAccess::loadload();
1002 const unsigned local_time_stamp = _gc_time_stamp;
1003 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
1004 if (local_time_stamp < g1h->get_gc_time_stamp()) {
1005 return local_top;
1006 } else {
1007 return _scan_top;
1008 }
1009 }
1010
1011 void G1OffsetTableContigSpace::record_timestamp() {
1012 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1013 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
1014
1015 if (_gc_time_stamp < curr_gc_time_stamp) {
1016 // Setting the time stamp here tells concurrent readers to look at
1017 // scan_top to know the maximum allowed address to look at.
1018
1019 // scan_top should be bottom for all regions except for the
1020 // retained old alloc region which should have scan_top == top
1021 HeapWord* st = _scan_top;
1022 guarantee(st == _bottom || st == _top, "invariant");
1023
1024 _gc_time_stamp = curr_gc_time_stamp;
1025 }
1026 }
1027
1028 void G1OffsetTableContigSpace::record_retained_region() {
1029 // scan_top is the maximum address where it's safe for the next gc to
1030 // scan this region.
1031 _scan_top = top();
1032 }
1033
1034 void G1OffsetTableContigSpace::safe_object_iterate(ObjectClosure* blk) {
1035 object_iterate(blk);
1036 }
1037
1038 void G1OffsetTableContigSpace::object_iterate(ObjectClosure* blk) {
1039 HeapWord* p = bottom();
1040 while (p < top()) {
1041 if (block_is_obj(p)) {
1042 blk->do_object(oop(p));
1043 }
1044 p += block_size(p);
1045 }
1046 }
1047
1048 G1OffsetTableContigSpace::
1049 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
1050 MemRegion mr) :
1051 _offsets(sharedOffsetArray, mr),
1052 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
1053 _gc_time_stamp(0)
1054 {
1055 _offsets.set_space(this);
1056 }
1057
1058 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
1059 CompactibleSpace::initialize(mr, clear_space, mangle_space);
1060 _top = bottom();
1061 _scan_top = bottom();
1062 set_saved_mark_word(NULL);
1063 reset_bot();
1064 }
1065