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/g1HeapRegionTraceType.hpp"
30 #include "gc/g1/g1OopClosures.inline.hpp"
31 #include "gc/g1/heapRegion.inline.hpp"
32 #include "gc/g1/heapRegionBounds.inline.hpp"
33 #include "gc/g1/heapRegionManager.inline.hpp"
34 #include "gc/g1/heapRegionRemSet.hpp"
35 #include "gc/g1/heapRegionTracer.hpp"
36 #include "gc/shared/genOopClosures.inline.hpp"
37 #include "gc/shared/liveRange.hpp"
38 #include "gc/shared/space.inline.hpp"
39 #include "logging/log.hpp"
40 #include "memory/iterator.hpp"
41 #include "oops/oop.inline.hpp"
42 #include "runtime/atomic.inline.hpp"
43 #include "runtime/orderAccess.inline.hpp"
44
45 int HeapRegion::LogOfHRGrainBytes = 0;
46 int HeapRegion::LogOfHRGrainWords = 0;
47 size_t HeapRegion::GrainBytes = 0;
48 size_t HeapRegion::GrainWords = 0;
49 size_t HeapRegion::CardsPerRegion = 0;
50
51 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
52 HeapRegion* hr,
53 G1ParPushHeapRSClosure* cl,
54 CardTableModRefBS::PrecisionStyle precision) :
55 DirtyCardToOopClosure(hr, cl, precision, NULL),
56 _hr(hr), _rs_scan(cl), _g1(g1) { }
57
58 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
59 OopClosure* oc) :
60 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
61
62 void HeapRegionDCTOC::walk_mem_region(MemRegion mr,
63 HeapWord* bottom,
64 HeapWord* top) {
65 G1CollectedHeap* g1h = _g1;
66 size_t oop_size;
67 HeapWord* cur = bottom;
68
69 // Start filtering what we add to the remembered set. If the object is
70 // not considered dead, either because it is marked (in the mark bitmap)
71 // or it was allocated after marking finished, then we add it. Otherwise
72 // we can safely ignore the object.
73 if (!g1h->is_obj_dead(oop(cur))) {
74 oop_size = oop(cur)->oop_iterate_size(_rs_scan, mr);
75 } else {
76 oop_size = _hr->block_size(cur);
77 }
78
79 cur += oop_size;
80
81 if (cur < top) {
82 oop cur_oop = oop(cur);
83 oop_size = _hr->block_size(cur);
84 HeapWord* next_obj = cur + oop_size;
85 while (next_obj < top) {
86 // Keep filtering the remembered set.
87 if (!g1h->is_obj_dead(cur_oop)) {
88 // Bottom lies entirely below top, so we can call the
89 // non-memRegion version of oop_iterate below.
90 cur_oop->oop_iterate(_rs_scan);
91 }
92 cur = next_obj;
93 cur_oop = oop(cur);
94 oop_size = _hr->block_size(cur);
95 next_obj = cur + oop_size;
96 }
97
98 // Last object. Need to do dead-obj filtering here too.
99 if (!g1h->is_obj_dead(oop(cur))) {
100 oop(cur)->oop_iterate(_rs_scan, mr);
101 }
102 }
103 }
104
105 size_t HeapRegion::max_region_size() {
106 return HeapRegionBounds::max_size();
107 }
108
109 size_t HeapRegion::min_region_size_in_words() {
110 return HeapRegionBounds::min_size() >> LogHeapWordSize;
111 }
112
113 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
114 size_t region_size = G1HeapRegionSize;
115 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
116 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
117 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(),
118 HeapRegionBounds::min_size());
119 }
120
121 int region_size_log = log2_long((jlong) region_size);
122 // Recalculate the region size to make sure it's a power of
123 // 2. This means that region_size is the largest power of 2 that's
124 // <= what we've calculated so far.
125 region_size = ((size_t)1 << region_size_log);
126
127 // Now make sure that we don't go over or under our limits.
128 if (region_size < HeapRegionBounds::min_size()) {
129 region_size = HeapRegionBounds::min_size();
130 } else if (region_size > HeapRegionBounds::max_size()) {
131 region_size = HeapRegionBounds::max_size();
132 }
133
134 // And recalculate the log.
135 region_size_log = log2_long((jlong) region_size);
136
137 // Now, set up the globals.
138 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
139 LogOfHRGrainBytes = region_size_log;
140
141 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
142 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
143
144 guarantee(GrainBytes == 0, "we should only set it once");
145 // The cast to int is safe, given that we've bounded region_size by
146 // MIN_REGION_SIZE and MAX_REGION_SIZE.
147 GrainBytes = region_size;
148 log_info(gc, heap)("Heap region size: " SIZE_FORMAT "M", GrainBytes / M);
149
150 guarantee(GrainWords == 0, "we should only set it once");
151 GrainWords = GrainBytes >> LogHeapWordSize;
152 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
153
154 guarantee(CardsPerRegion == 0, "we should only set it once");
155 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
156 }
157
158 void HeapRegion::reset_after_compaction() {
159 G1ContiguousSpace::reset_after_compaction();
160 // After a compaction the mark bitmap is invalid, so we must
161 // treat all objects as being inside the unmarked area.
162 zero_marked_bytes();
163 init_top_at_mark_start();
164 }
165
166 void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
167 assert(_humongous_start_region == NULL,
168 "we should have already filtered out humongous regions");
169 assert(!in_collection_set(),
170 "Should not clear heap region %u in the collection set", hrm_index());
171
172 set_allocation_context(AllocationContext::system());
173 set_young_index_in_cset(-1);
174 uninstall_surv_rate_group();
175 set_free();
176 reset_pre_dummy_top();
177
178 if (!par) {
179 // If this is parallel, this will be done later.
180 HeapRegionRemSet* hrrs = rem_set();
181 if (locked) {
182 hrrs->clear_locked();
183 } else {
184 hrrs->clear();
185 }
186 }
187 zero_marked_bytes();
188
189 init_top_at_mark_start();
190 if (clear_space) clear(SpaceDecorator::Mangle);
191 }
192
193 void HeapRegion::par_clear() {
194 assert(used() == 0, "the region should have been already cleared");
195 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
196 HeapRegionRemSet* hrrs = rem_set();
197 hrrs->clear();
198 CardTableModRefBS* ct_bs =
199 barrier_set_cast<CardTableModRefBS>(G1CollectedHeap::heap()->barrier_set());
200 ct_bs->clear(MemRegion(bottom(), end()));
201 }
202
203 void HeapRegion::calc_gc_efficiency() {
204 // GC efficiency is the ratio of how much space would be
205 // reclaimed over how long we predict it would take to reclaim it.
206 G1CollectedHeap* g1h = G1CollectedHeap::heap();
207 G1CollectorPolicy* g1p = g1h->g1_policy();
208
209 // Retrieve a prediction of the elapsed time for this region for
210 // a mixed gc because the region will only be evacuated during a
211 // mixed gc.
212 double region_elapsed_time_ms =
213 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
214 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
215 }
216
217 void HeapRegion::set_starts_humongous(HeapWord* obj_top, size_t fill_size) {
218 assert(!is_humongous(), "sanity / pre-condition");
219 assert(top() == bottom(), "should be empty");
220
221 report_region_type_change(G1HeapRegionTraceType::StartsHumongous);
222 _type.set_starts_humongous();
223 _humongous_start_region = this;
224
225 _bot_part.set_for_starts_humongous(obj_top, fill_size);
226 }
227
228 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) {
229 assert(!is_humongous(), "sanity / pre-condition");
230 assert(top() == bottom(), "should be empty");
231 assert(first_hr->is_starts_humongous(), "pre-condition");
232
233 report_region_type_change(G1HeapRegionTraceType::ContinuesHumongous);
234 _type.set_continues_humongous();
235 _humongous_start_region = first_hr;
236 }
237
238 void HeapRegion::clear_humongous() {
239 assert(is_humongous(), "pre-condition");
240
241 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
242 _humongous_start_region = NULL;
243 }
244
245 HeapRegion::HeapRegion(uint hrm_index,
246 G1BlockOffsetTable* bot,
247 MemRegion mr) :
248 G1ContiguousSpace(bot),
249 _hrm_index(hrm_index),
250 _allocation_context(AllocationContext::system()),
251 _humongous_start_region(NULL),
252 _next_in_special_set(NULL),
253 _evacuation_failed(false),
254 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
255 _next_young_region(NULL),
256 _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL),
257 #ifdef ASSERT
258 _containing_set(NULL),
259 #endif // ASSERT
260 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
261 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
262 _predicted_bytes_to_copy(0)
263 {
264 _rem_set = new HeapRegionRemSet(bot, this);
265
266 initialize(mr);
267 }
268
269 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
270 assert(_rem_set->is_empty(), "Remembered set must be empty");
271
272 G1ContiguousSpace::initialize(mr, clear_space, mangle_space);
273
274 hr_clear(false /*par*/, false /*clear_space*/);
275 set_top(bottom());
276 record_timestamp();
277 }
278
279 void HeapRegion::report_region_type_change(G1HeapRegionTraceType::Type to) {
280 HeapRegionTracer::send_region_type_change(_hrm_index,
281 get_trace_type(),
282 to,
283 (uintptr_t)bottom(),
284 used(),
285 (uint)allocation_context());
286 }
287
288 CompactibleSpace* HeapRegion::next_compaction_space() const {
289 return G1CollectedHeap::heap()->next_compaction_region(this);
290 }
291
292 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
293 bool during_conc_mark) {
294 // We always recreate the prev marking info and we'll explicitly
295 // mark all objects we find to be self-forwarded on the prev
296 // bitmap. So all objects need to be below PTAMS.
297 _prev_marked_bytes = 0;
298
299 if (during_initial_mark) {
300 // During initial-mark, we'll also explicitly mark all objects
301 // we find to be self-forwarded on the next bitmap. So all
302 // objects need to be below NTAMS.
303 _next_top_at_mark_start = top();
304 _next_marked_bytes = 0;
305 } else if (during_conc_mark) {
306 // During concurrent mark, all objects in the CSet (including
307 // the ones we find to be self-forwarded) are implicitly live.
308 // So all objects need to be above NTAMS.
309 _next_top_at_mark_start = bottom();
310 _next_marked_bytes = 0;
311 }
312 }
313
314 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
315 bool during_conc_mark,
316 size_t marked_bytes) {
317 assert(marked_bytes <= used(),
318 "marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used());
319 _prev_top_at_mark_start = top();
320 _prev_marked_bytes = marked_bytes;
321 }
322
323 HeapWord*
324 HeapRegion::object_iterate_mem_careful(MemRegion mr,
325 ObjectClosure* cl) {
326 G1CollectedHeap* g1h = G1CollectedHeap::heap();
327 // We used to use "block_start_careful" here. But we're actually happy
328 // to update the BOT while we do this...
329 HeapWord* cur = block_start(mr.start());
330 mr = mr.intersection(used_region());
331 if (mr.is_empty()) return NULL;
332 // Otherwise, find the obj that extends onto mr.start().
333
334 assert(cur <= mr.start()
335 && (oop(cur)->klass_or_null() == NULL ||
336 cur + oop(cur)->size() > mr.start()),
337 "postcondition of block_start");
338 oop obj;
339 while (cur < mr.end()) {
340 obj = oop(cur);
341 if (obj->klass_or_null() == NULL) {
342 // Ran into an unparseable point.
343 return cur;
344 } else if (!g1h->is_obj_dead(obj)) {
345 cl->do_object(obj);
346 }
347 cur += block_size(cur);
348 }
349 return NULL;
350 }
351
352 HeapWord*
353 HeapRegion::
354 oops_on_card_seq_iterate_careful(MemRegion mr,
355 FilterOutOfRegionClosure* cl,
356 bool filter_young,
357 jbyte* card_ptr) {
358 // Currently, we should only have to clean the card if filter_young
359 // is true and vice versa.
360 if (filter_young) {
361 assert(card_ptr != NULL, "pre-condition");
362 } else {
363 assert(card_ptr == NULL, "pre-condition");
364 }
365 G1CollectedHeap* g1h = G1CollectedHeap::heap();
366
367 // If we're within a stop-world GC, then we might look at a card in a
368 // GC alloc region that extends onto a GC LAB, which may not be
369 // parseable. Stop such at the "scan_top" of the region.
370 if (g1h->is_gc_active()) {
371 mr = mr.intersection(MemRegion(bottom(), scan_top()));
372 } else {
373 mr = mr.intersection(used_region());
374 }
375 if (mr.is_empty()) return NULL;
376 // Otherwise, find the obj that extends onto mr.start().
377
378 // The intersection of the incoming mr (for the card) and the
379 // allocated part of the region is non-empty. This implies that
380 // we have actually allocated into this region. The code in
381 // G1CollectedHeap.cpp that allocates a new region sets the
382 // is_young tag on the region before allocating. Thus we
383 // safely know if this region is young.
384 if (is_young() && filter_young) {
385 return NULL;
386 }
387
388 assert(!is_young(), "check value of filter_young");
389
390 // We can only clean the card here, after we make the decision that
391 // the card is not young. And we only clean the card if we have been
392 // asked to (i.e., card_ptr != NULL).
393 if (card_ptr != NULL) {
394 *card_ptr = CardTableModRefBS::clean_card_val();
395 // We must complete this write before we do any of the reads below.
396 OrderAccess::storeload();
397 }
398
399 // Cache the boundaries of the memory region in some const locals
400 HeapWord* const start = mr.start();
401 HeapWord* const end = mr.end();
402
403 // We used to use "block_start_careful" here. But we're actually happy
404 // to update the BOT while we do this...
405 HeapWord* cur = block_start(start);
406 assert(cur <= start, "Postcondition");
407
408 oop obj;
409
410 HeapWord* next = cur;
411 do {
412 cur = next;
413 obj = oop(cur);
414 if (obj->klass_or_null() == NULL) {
415 // Ran into an unparseable point.
416 return cur;
417 }
418 // Otherwise...
419 next = cur + block_size(cur);
420 } while (next <= start);
421
422 // If we finish the above loop...We have a parseable object that
423 // begins on or before the start of the memory region, and ends
424 // inside or spans the entire region.
425 assert(cur <= start, "Loop postcondition");
426 assert(obj->klass_or_null() != NULL, "Loop postcondition");
427
428 do {
429 obj = oop(cur);
430 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant");
431 if (obj->klass_or_null() == NULL) {
432 // Ran into an unparseable point.
433 return cur;
434 }
435
436 // Advance the current pointer. "obj" still points to the object to iterate.
437 cur = cur + block_size(cur);
438
439 if (!g1h->is_obj_dead(obj)) {
440 // Non-objArrays are sometimes marked imprecise at the object start. We
441 // always need to iterate over them in full.
442 // We only iterate over object arrays in full if they are completely contained
443 // in the memory region.
444 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) {
445 obj->oop_iterate(cl);
446 } else {
447 obj->oop_iterate(cl, mr);
448 }
449 }
450 } while (cur < end);
451
452 return NULL;
453 }
454
455 // Code roots support
456
457 void HeapRegion::add_strong_code_root(nmethod* nm) {
458 HeapRegionRemSet* hrrs = rem_set();
459 hrrs->add_strong_code_root(nm);
460 }
461
462 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
463 assert_locked_or_safepoint(CodeCache_lock);
464 HeapRegionRemSet* hrrs = rem_set();
465 hrrs->add_strong_code_root_locked(nm);
466 }
467
468 void HeapRegion::remove_strong_code_root(nmethod* nm) {
469 HeapRegionRemSet* hrrs = rem_set();
470 hrrs->remove_strong_code_root(nm);
471 }
472
473 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
474 HeapRegionRemSet* hrrs = rem_set();
475 hrrs->strong_code_roots_do(blk);
476 }
477
478 class VerifyStrongCodeRootOopClosure: public OopClosure {
479 const HeapRegion* _hr;
480 nmethod* _nm;
481 bool _failures;
482 bool _has_oops_in_region;
483
484 template <class T> void do_oop_work(T* p) {
485 T heap_oop = oopDesc::load_heap_oop(p);
486 if (!oopDesc::is_null(heap_oop)) {
487 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
488
489 // Note: not all the oops embedded in the nmethod are in the
490 // current region. We only look at those which are.
491 if (_hr->is_in(obj)) {
492 // Object is in the region. Check that its less than top
493 if (_hr->top() <= (HeapWord*)obj) {
494 // Object is above top
495 log_info(gc, verify)("Object " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ") is above top " PTR_FORMAT,
496 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top()));
497 _failures = true;
498 return;
499 }
500 // Nmethod has at least one oop in the current region
501 _has_oops_in_region = true;
502 }
503 }
504 }
505
506 public:
507 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
508 _hr(hr), _failures(false), _has_oops_in_region(false) {}
509
510 void do_oop(narrowOop* p) { do_oop_work(p); }
511 void do_oop(oop* p) { do_oop_work(p); }
512
513 bool failures() { return _failures; }
514 bool has_oops_in_region() { return _has_oops_in_region; }
515 };
516
517 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
518 const HeapRegion* _hr;
519 bool _failures;
520 public:
521 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
522 _hr(hr), _failures(false) {}
523
524 void do_code_blob(CodeBlob* cb) {
525 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
526 if (nm != NULL) {
527 // Verify that the nemthod is live
528 if (!nm->is_alive()) {
529 log_info(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " PTR_FORMAT " in its strong code roots",
530 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
531 _failures = true;
532 } else {
533 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
534 nm->oops_do(&oop_cl);
535 if (!oop_cl.has_oops_in_region()) {
536 log_info(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " PTR_FORMAT " in its strong code roots with no pointers into region",
537 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
538 _failures = true;
539 } else if (oop_cl.failures()) {
540 log_info(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has other failures for nmethod " PTR_FORMAT,
541 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
542 _failures = true;
543 }
544 }
545 }
546 }
547
548 bool failures() { return _failures; }
549 };
550
551 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
552 if (!G1VerifyHeapRegionCodeRoots) {
553 // We're not verifying code roots.
554 return;
555 }
556 if (vo == VerifyOption_G1UseMarkWord) {
557 // Marking verification during a full GC is performed after class
558 // unloading, code cache unloading, etc so the strong code roots
559 // attached to each heap region are in an inconsistent state. They won't
560 // be consistent until the strong code roots are rebuilt after the
561 // actual GC. Skip verifying the strong code roots in this particular
562 // time.
563 assert(VerifyDuringGC, "only way to get here");
564 return;
565 }
566
567 HeapRegionRemSet* hrrs = rem_set();
568 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
569
570 // if this region is empty then there should be no entries
571 // on its strong code root list
572 if (is_empty()) {
573 if (strong_code_roots_length > 0) {
574 log_info(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] is empty but has " SIZE_FORMAT " code root entries",
575 p2i(bottom()), p2i(end()), strong_code_roots_length);
576 *failures = true;
577 }
578 return;
579 }
580
581 if (is_continues_humongous()) {
582 if (strong_code_roots_length > 0) {
583 log_info(gc, verify)("region " HR_FORMAT " is a continuation of a humongous region but has " SIZE_FORMAT " code root entries",
584 HR_FORMAT_PARAMS(this), strong_code_roots_length);
585 *failures = true;
586 }
587 return;
588 }
589
590 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
591 strong_code_roots_do(&cb_cl);
592
593 if (cb_cl.failures()) {
594 *failures = true;
595 }
596 }
597
598 void HeapRegion::print() const { print_on(tty); }
599 void HeapRegion::print_on(outputStream* st) const {
600 st->print("|%4u", this->_hrm_index);
601 st->print("|" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT,
602 p2i(bottom()), p2i(top()), p2i(end()));
603 st->print("|%3d%%", (int) ((double) used() * 100 / capacity()));
604 st->print("|%2s", get_short_type_str());
605 if (in_collection_set()) {
606 st->print("|CS");
607 } else {
608 st->print("| ");
609 }
610 st->print("|TS%3u", _gc_time_stamp);
611 st->print("|AC%3u", allocation_context());
612 st->print_cr("|TAMS " PTR_FORMAT ", " PTR_FORMAT "|",
613 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start()));
614 }
615
616 class G1VerificationClosure : public OopClosure {
617 protected:
618 G1CollectedHeap* _g1h;
619 CardTableModRefBS* _bs;
620 oop _containing_obj;
621 bool _failures;
622 int _n_failures;
623 VerifyOption _vo;
624 public:
625 // _vo == UsePrevMarking -> use "prev" marking information,
626 // _vo == UseNextMarking -> use "next" marking information,
627 // _vo == UseMarkWord -> use mark word from object header.
628 G1VerificationClosure(G1CollectedHeap* g1h, VerifyOption vo) :
629 _g1h(g1h), _bs(barrier_set_cast<CardTableModRefBS>(g1h->barrier_set())),
630 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo) {
631 }
632
633 void set_containing_obj(oop obj) {
634 _containing_obj = obj;
635 }
636
637 bool failures() { return _failures; }
638 int n_failures() { return _n_failures; }
639
640 void print_object(outputStream* out, oop obj) {
641 #ifdef PRODUCT
642 Klass* k = obj->klass();
643 const char* class_name = k->external_name();
644 out->print_cr("class name %s", class_name);
645 #else // PRODUCT
646 obj->print_on(out);
647 #endif // PRODUCT
648 }
649 };
650
651 class VerifyLiveClosure : public G1VerificationClosure {
652 public:
653 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
654 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
655 virtual void do_oop(oop* p) { do_oop_work(p); }
656
657 template <class T>
658 void do_oop_work(T* p) {
659 assert(_containing_obj != NULL, "Precondition");
660 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
661 "Precondition");
662 verify_liveness(p);
663 }
664
665 template <class T>
666 void verify_liveness(T* p) {
667 T heap_oop = oopDesc::load_heap_oop(p);
668 LogHandle(gc, verify) log;
669 if (!oopDesc::is_null(heap_oop)) {
670 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
671 bool failed = false;
672 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
673 MutexLockerEx x(ParGCRareEvent_lock,
674 Mutex::_no_safepoint_check_flag);
675
676 if (!_failures) {
677 log.info("----------");
678 }
679 ResourceMark rm;
680 if (!_g1h->is_in_closed_subset(obj)) {
681 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
682 log.info("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
683 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
684 print_object(log.info_stream(), _containing_obj);
685 log.info("points to obj " PTR_FORMAT " not in the heap", p2i(obj));
686 } else {
687 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
688 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
689 log.info("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
690 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
691 print_object(log.info_stream(), _containing_obj);
692 log.info("points to dead obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
693 p2i(obj), p2i(to->bottom()), p2i(to->end()));
694 print_object(log.info_stream(), obj);
695 }
696 log.info("----------");
697 _failures = true;
698 failed = true;
699 _n_failures++;
700 }
701 }
702 }
703 };
704
705 class VerifyRemSetClosure : public G1VerificationClosure {
706 public:
707 VerifyRemSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
708 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
709 virtual void do_oop(oop* p) { do_oop_work(p); }
710
711 template <class T>
712 void do_oop_work(T* p) {
713 assert(_containing_obj != NULL, "Precondition");
714 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
715 "Precondition");
716 verify_remembered_set(p);
717 }
718
719 template <class T>
720 void verify_remembered_set(T* p) {
721 T heap_oop = oopDesc::load_heap_oop(p);
722 LogHandle(gc, verify) log;
723 if (!oopDesc::is_null(heap_oop)) {
724 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
725 bool failed = false;
726 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
727 HeapRegion* to = _g1h->heap_region_containing(obj);
728 if (from != NULL && to != NULL &&
729 from != to &&
730 !to->is_pinned()) {
731 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
732 jbyte cv_field = *_bs->byte_for_const(p);
733 const jbyte dirty = CardTableModRefBS::dirty_card_val();
734
735 bool is_bad = !(from->is_young()
736 || to->rem_set()->contains_reference(p)
737 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
738 (_containing_obj->is_objArray() ?
739 cv_field == dirty
740 : cv_obj == dirty || cv_field == dirty));
741 if (is_bad) {
742 MutexLockerEx x(ParGCRareEvent_lock,
743 Mutex::_no_safepoint_check_flag);
744
745 if (!_failures) {
746 log.info("----------");
747 }
748 log.info("Missing rem set entry:");
749 log.info("Field " PTR_FORMAT " of obj " PTR_FORMAT ", in region " HR_FORMAT,
750 p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
751 ResourceMark rm;
752 _containing_obj->print_on(log.info_stream());
753 log.info("points to obj " PTR_FORMAT " in region " HR_FORMAT, p2i(obj), HR_FORMAT_PARAMS(to));
754 obj->print_on(log.info_stream());
755 log.info("Obj head CTE = %d, field CTE = %d.", cv_obj, cv_field);
756 log.info("----------");
757 _failures = true;
758 if (!failed) _n_failures++;
759 }
760 }
761 }
762 }
763 };
764
765 // This really ought to be commoned up into OffsetTableContigSpace somehow.
766 // We would need a mechanism to make that code skip dead objects.
767
768 void HeapRegion::verify(VerifyOption vo,
769 bool* failures) const {
770 G1CollectedHeap* g1 = G1CollectedHeap::heap();
771 *failures = false;
772 HeapWord* p = bottom();
773 HeapWord* prev_p = NULL;
774 VerifyLiveClosure vl_cl(g1, vo);
775 VerifyRemSetClosure vr_cl(g1, vo);
776 bool is_region_humongous = is_humongous();
777 size_t object_num = 0;
778 while (p < top()) {
779 oop obj = oop(p);
780 size_t obj_size = block_size(p);
781 object_num += 1;
782
783 if (!g1->is_obj_dead_cond(obj, this, vo)) {
784 if (obj->is_oop()) {
785 Klass* klass = obj->klass();
786 bool is_metaspace_object = Metaspace::contains(klass) ||
787 (vo == VerifyOption_G1UsePrevMarking &&
788 ClassLoaderDataGraph::unload_list_contains(klass));
789 if (!is_metaspace_object) {
790 log_info(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
791 "not metadata", p2i(klass), p2i(obj));
792 *failures = true;
793 return;
794 } else if (!klass->is_klass()) {
795 log_info(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
796 "not a klass", p2i(klass), p2i(obj));
797 *failures = true;
798 return;
799 } else {
800 vl_cl.set_containing_obj(obj);
801 if (!g1->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) {
802 // verify liveness and rem_set
803 vr_cl.set_containing_obj(obj);
804 G1Mux2Closure mux(&vl_cl, &vr_cl);
805 obj->oop_iterate_no_header(&mux);
806
807 if (vr_cl.failures()) {
808 *failures = true;
809 }
810 if (G1MaxVerifyFailures >= 0 &&
811 vr_cl.n_failures() >= G1MaxVerifyFailures) {
812 return;
813 }
814 } else {
815 // verify only liveness
816 obj->oop_iterate_no_header(&vl_cl);
817 }
818 if (vl_cl.failures()) {
819 *failures = true;
820 }
821 if (G1MaxVerifyFailures >= 0 &&
822 vl_cl.n_failures() >= G1MaxVerifyFailures) {
823 return;
824 }
825 }
826 } else {
827 log_info(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
828 *failures = true;
829 return;
830 }
831 }
832 prev_p = p;
833 p += obj_size;
834 }
835
836 if (!is_young() && !is_empty()) {
837 _bot_part.verify();
838 }
839
840 if (is_region_humongous) {
841 oop obj = oop(this->humongous_start_region()->bottom());
842 if ((HeapWord*)obj > bottom() || (HeapWord*)obj + obj->size() < bottom()) {
843 log_info(gc, verify)("this humongous region is not part of its' humongous object " PTR_FORMAT, p2i(obj));
844 }
845 }
846
847 if (!is_region_humongous && p != top()) {
848 log_info(gc, verify)("end of last object " PTR_FORMAT " "
849 "does not match top " PTR_FORMAT, p2i(p), p2i(top()));
850 *failures = true;
851 return;
852 }
853
854 HeapWord* the_end = end();
855 // Do some extra BOT consistency checking for addresses in the
856 // range [top, end). BOT look-ups in this range should yield
857 // top. No point in doing that if top == end (there's nothing there).
858 if (p < the_end) {
859 // Look up top
860 HeapWord* addr_1 = p;
861 HeapWord* b_start_1 = _bot_part.block_start_const(addr_1);
862 if (b_start_1 != p) {
863 log_info(gc, verify)("BOT look up for top: " PTR_FORMAT " "
864 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
865 p2i(addr_1), p2i(b_start_1), p2i(p));
866 *failures = true;
867 return;
868 }
869
870 // Look up top + 1
871 HeapWord* addr_2 = p + 1;
872 if (addr_2 < the_end) {
873 HeapWord* b_start_2 = _bot_part.block_start_const(addr_2);
874 if (b_start_2 != p) {
875 log_info(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " "
876 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
877 p2i(addr_2), p2i(b_start_2), p2i(p));
878 *failures = true;
879 return;
880 }
881 }
882
883 // Look up an address between top and end
884 size_t diff = pointer_delta(the_end, p) / 2;
885 HeapWord* addr_3 = p + diff;
886 if (addr_3 < the_end) {
887 HeapWord* b_start_3 = _bot_part.block_start_const(addr_3);
888 if (b_start_3 != p) {
889 log_info(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " "
890 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
891 p2i(addr_3), p2i(b_start_3), p2i(p));
892 *failures = true;
893 return;
894 }
895 }
896
897 // Look up end - 1
898 HeapWord* addr_4 = the_end - 1;
899 HeapWord* b_start_4 = _bot_part.block_start_const(addr_4);
900 if (b_start_4 != p) {
901 log_info(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " "
902 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
903 p2i(addr_4), p2i(b_start_4), p2i(p));
904 *failures = true;
905 return;
906 }
907 }
908
909 verify_strong_code_roots(vo, failures);
910 }
911
912 void HeapRegion::verify() const {
913 bool dummy = false;
914 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
915 }
916
917 void HeapRegion::verify_rem_set(VerifyOption vo, bool* failures) const {
918 G1CollectedHeap* g1 = G1CollectedHeap::heap();
919 *failures = false;
920 HeapWord* p = bottom();
921 HeapWord* prev_p = NULL;
922 VerifyRemSetClosure vr_cl(g1, vo);
923 while (p < top()) {
924 oop obj = oop(p);
925 size_t obj_size = block_size(p);
926
927 if (!g1->is_obj_dead_cond(obj, this, vo)) {
928 if (obj->is_oop()) {
929 vr_cl.set_containing_obj(obj);
930 obj->oop_iterate_no_header(&vr_cl);
931
932 if (vr_cl.failures()) {
933 *failures = true;
934 }
935 if (G1MaxVerifyFailures >= 0 &&
936 vr_cl.n_failures() >= G1MaxVerifyFailures) {
937 return;
938 }
939 } else {
940 log_info(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
941 *failures = true;
942 return;
943 }
944 }
945
946 prev_p = p;
947 p += obj_size;
948 }
949 }
950
951 void HeapRegion::verify_rem_set() const {
952 bool failures = false;
953 verify_rem_set(VerifyOption_G1UsePrevMarking, &failures);
954 guarantee(!failures, "HeapRegion RemSet verification failed");
955 }
956
957 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
958 scan_and_forward(this, cp);
959 }
960
961 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
962 // away eventually.
963
964 void G1ContiguousSpace::clear(bool mangle_space) {
965 set_top(bottom());
966 _scan_top = bottom();
967 CompactibleSpace::clear(mangle_space);
968 reset_bot();
969 }
970
971 #ifndef PRODUCT
972 void G1ContiguousSpace::mangle_unused_area() {
973 mangle_unused_area_complete();
974 }
975
976 void G1ContiguousSpace::mangle_unused_area_complete() {
977 SpaceMangler::mangle_region(MemRegion(top(), end()));
978 }
979 #endif
980
981 void G1ContiguousSpace::print() const {
982 print_short();
983 tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
984 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
985 p2i(bottom()), p2i(top()), p2i(_bot_part.threshold()), p2i(end()));
986 }
987
988 HeapWord* G1ContiguousSpace::initialize_threshold() {
989 return _bot_part.initialize_threshold();
990 }
991
992 HeapWord* G1ContiguousSpace::cross_threshold(HeapWord* start,
993 HeapWord* end) {
994 _bot_part.alloc_block(start, end);
995 return _bot_part.threshold();
996 }
997
998 HeapWord* G1ContiguousSpace::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 G1ContiguousSpace::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 G1ContiguousSpace::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 G1ContiguousSpace::safe_object_iterate(ObjectClosure* blk) {
1035 object_iterate(blk);
1036 }
1037
1038 void G1ContiguousSpace::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 G1ContiguousSpace::G1ContiguousSpace(G1BlockOffsetTable* bot) :
1049 _bot_part(bot, this),
1050 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
1051 _gc_time_stamp(0)
1052 {
1053 }
1054
1055 void G1ContiguousSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
1056 CompactibleSpace::initialize(mr, clear_space, mangle_space);
1057 _top = bottom();
1058 _scan_top = bottom();
1059 set_saved_mark_word(NULL);
1060 reset_bot();
1061 }
1062