1 /*
2 * Copyright (c) 2001, 2017, 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/space.inline.hpp"
38 #include "logging/log.hpp"
39 #include "memory/iterator.hpp"
40 #include "memory/resourceArea.hpp"
41 #include "oops/oop.inline.hpp"
42 #include "runtime/atomic.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 void HeapRegionDCTOC::walk_mem_region(MemRegion mr,
59 HeapWord* bottom,
60 HeapWord* top) {
61 G1CollectedHeap* g1h = _g1;
62 size_t oop_size;
63 HeapWord* cur = bottom;
64
65 // Start filtering what we add to the remembered set. If the object is
66 // not considered dead, either because it is marked (in the mark bitmap)
67 // or it was allocated after marking finished, then we add it. Otherwise
68 // we can safely ignore the object.
69 if (!g1h->is_obj_dead(oop(cur))) {
70 oop_size = oop(cur)->oop_iterate_size(_rs_scan, mr);
71 } else {
72 oop_size = _hr->block_size(cur);
73 }
74
75 cur += oop_size;
76
77 if (cur < top) {
78 oop cur_oop = oop(cur);
79 oop_size = _hr->block_size(cur);
80 HeapWord* next_obj = cur + oop_size;
81 while (next_obj < top) {
82 // Keep filtering the remembered set.
83 if (!g1h->is_obj_dead(cur_oop)) {
84 // Bottom lies entirely below top, so we can call the
85 // non-memRegion version of oop_iterate below.
86 cur_oop->oop_iterate(_rs_scan);
87 }
88 cur = next_obj;
89 cur_oop = oop(cur);
90 oop_size = _hr->block_size(cur);
91 next_obj = cur + oop_size;
92 }
93
94 // Last object. Need to do dead-obj filtering here too.
95 if (!g1h->is_obj_dead(oop(cur))) {
96 oop(cur)->oop_iterate(_rs_scan, mr);
97 }
98 }
99 }
100
101 size_t HeapRegion::max_region_size() {
102 return HeapRegionBounds::max_size();
103 }
104
105 size_t HeapRegion::min_region_size_in_words() {
106 return HeapRegionBounds::min_size() >> LogHeapWordSize;
107 }
108
109 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
110 size_t region_size = G1HeapRegionSize;
111 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
112 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
113 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(),
114 HeapRegionBounds::min_size());
115 }
116
117 int region_size_log = log2_long((jlong) region_size);
118 // Recalculate the region size to make sure it's a power of
119 // 2. This means that region_size is the largest power of 2 that's
120 // <= what we've calculated so far.
121 region_size = ((size_t)1 << region_size_log);
122
123 // Now make sure that we don't go over or under our limits.
124 if (region_size < HeapRegionBounds::min_size()) {
125 region_size = HeapRegionBounds::min_size();
126 } else if (region_size > HeapRegionBounds::max_size()) {
127 region_size = HeapRegionBounds::max_size();
128 }
129
130 // And recalculate the log.
131 region_size_log = log2_long((jlong) region_size);
132
133 // Now, set up the globals.
134 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
135 LogOfHRGrainBytes = region_size_log;
136
137 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
138 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
139
140 guarantee(GrainBytes == 0, "we should only set it once");
141 // The cast to int is safe, given that we've bounded region_size by
142 // MIN_REGION_SIZE and MAX_REGION_SIZE.
143 GrainBytes = region_size;
144 log_info(gc, heap)("Heap region size: " SIZE_FORMAT "M", GrainBytes / M);
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 if (G1HeapRegionSize != GrainBytes) {
154 FLAG_SET_ERGO(size_t, G1HeapRegionSize, GrainBytes);
155 }
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 keep_remset, 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 (!keep_remset) {
179 if (locked) {
180 rem_set()->clear_locked();
181 } else {
182 rem_set()->clear();
183 }
184 }
185
186 zero_marked_bytes();
187
188 init_top_at_mark_start();
189 _gc_time_stamp = G1CollectedHeap::heap()->get_gc_time_stamp();
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 G1Policy* 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_free() {
218 report_region_type_change(G1HeapRegionTraceType::Free);
219 _type.set_free();
220 }
221
222 void HeapRegion::set_eden() {
223 report_region_type_change(G1HeapRegionTraceType::Eden);
224 _type.set_eden();
225 }
226
227 void HeapRegion::set_eden_pre_gc() {
228 report_region_type_change(G1HeapRegionTraceType::Eden);
229 _type.set_eden_pre_gc();
230 }
231
232 void HeapRegion::set_survivor() {
233 report_region_type_change(G1HeapRegionTraceType::Survivor);
234 _type.set_survivor();
235 }
236
237 void HeapRegion::set_old() {
238 report_region_type_change(G1HeapRegionTraceType::Old);
239 _type.set_old();
240 }
241
242 void HeapRegion::set_archive() {
243 report_region_type_change(G1HeapRegionTraceType::Archive);
244 _type.set_archive();
245 }
246
247 void HeapRegion::set_starts_humongous(HeapWord* obj_top, size_t fill_size) {
248 assert(!is_humongous(), "sanity / pre-condition");
249 assert(top() == bottom(), "should be empty");
250
251 report_region_type_change(G1HeapRegionTraceType::StartsHumongous);
252 _type.set_starts_humongous();
253 _humongous_start_region = this;
254
255 _bot_part.set_for_starts_humongous(obj_top, fill_size);
256 }
257
258 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) {
259 assert(!is_humongous(), "sanity / pre-condition");
260 assert(top() == bottom(), "should be empty");
261 assert(first_hr->is_starts_humongous(), "pre-condition");
262
263 report_region_type_change(G1HeapRegionTraceType::ContinuesHumongous);
264 _type.set_continues_humongous();
265 _humongous_start_region = first_hr;
266
267 _bot_part.set_object_can_span(true);
268 }
269
270 void HeapRegion::clear_humongous() {
271 assert(is_humongous(), "pre-condition");
272
273 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
274 _humongous_start_region = NULL;
275
276 _bot_part.set_object_can_span(false);
277 }
278
279 HeapRegion::HeapRegion(uint hrm_index,
280 G1BlockOffsetTable* bot,
281 MemRegion mr) :
282 G1ContiguousSpace(bot),
283 _hrm_index(hrm_index),
284 _allocation_context(AllocationContext::system()),
285 _humongous_start_region(NULL),
286 _evacuation_failed(false),
287 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
288 _next(NULL), _prev(NULL),
289 #ifdef ASSERT
290 _containing_set(NULL),
291 #endif // ASSERT
292 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
293 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0)
294 {
295 _rem_set = new HeapRegionRemSet(bot, this);
296
297 initialize(mr);
298 }
299
300 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
301 assert(_rem_set->is_empty(), "Remembered set must be empty");
302
303 G1ContiguousSpace::initialize(mr, clear_space, mangle_space);
304
305 hr_clear(false /*par*/, false /*clear_space*/);
306 set_top(bottom());
307 record_timestamp();
308 }
309
310 void HeapRegion::report_region_type_change(G1HeapRegionTraceType::Type to) {
311 HeapRegionTracer::send_region_type_change(_hrm_index,
312 get_trace_type(),
313 to,
314 (uintptr_t)bottom(),
315 used(),
316 (uint)allocation_context());
317 }
318
319 CompactibleSpace* HeapRegion::next_compaction_space() const {
320 return G1CollectedHeap::heap()->next_compaction_region(this);
321 }
322
323 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
324 bool during_conc_mark) {
325 // We always recreate the prev marking info and we'll explicitly
326 // mark all objects we find to be self-forwarded on the prev
327 // bitmap. So all objects need to be below PTAMS.
328 _prev_marked_bytes = 0;
329
330 if (during_initial_mark) {
331 // During initial-mark, we'll also explicitly mark all objects
332 // we find to be self-forwarded on the next bitmap. So all
333 // objects need to be below NTAMS.
334 _next_top_at_mark_start = top();
335 _next_marked_bytes = 0;
336 } else if (during_conc_mark) {
337 // During concurrent mark, all objects in the CSet (including
338 // the ones we find to be self-forwarded) are implicitly live.
339 // So all objects need to be above NTAMS.
340 _next_top_at_mark_start = bottom();
341 _next_marked_bytes = 0;
342 }
343 }
344
345 void HeapRegion::note_self_forwarding_removal_end(size_t marked_bytes) {
346 assert(marked_bytes <= used(),
347 "marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used());
348 _prev_top_at_mark_start = top();
349 _prev_marked_bytes = marked_bytes;
350 }
351
352 // Code roots support
353
354 void HeapRegion::add_strong_code_root(nmethod* nm) {
355 HeapRegionRemSet* hrrs = rem_set();
356 hrrs->add_strong_code_root(nm);
357 }
358
359 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
360 assert_locked_or_safepoint(CodeCache_lock);
361 HeapRegionRemSet* hrrs = rem_set();
362 hrrs->add_strong_code_root_locked(nm);
363 }
364
365 void HeapRegion::remove_strong_code_root(nmethod* nm) {
366 HeapRegionRemSet* hrrs = rem_set();
367 hrrs->remove_strong_code_root(nm);
368 }
369
370 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
371 HeapRegionRemSet* hrrs = rem_set();
372 hrrs->strong_code_roots_do(blk);
373 }
374
375 class VerifyStrongCodeRootOopClosure: public OopClosure {
376 const HeapRegion* _hr;
377 bool _failures;
378 bool _has_oops_in_region;
379
380 template <class T> void do_oop_work(T* p) {
381 T heap_oop = oopDesc::load_heap_oop(p);
382 if (!oopDesc::is_null(heap_oop)) {
383 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
384
385 // Note: not all the oops embedded in the nmethod are in the
386 // current region. We only look at those which are.
387 if (_hr->is_in(obj)) {
388 // Object is in the region. Check that its less than top
389 if (_hr->top() <= (HeapWord*)obj) {
390 // Object is above top
391 log_error(gc, verify)("Object " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ") is above top " PTR_FORMAT,
392 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top()));
393 _failures = true;
394 return;
395 }
396 // Nmethod has at least one oop in the current region
397 _has_oops_in_region = true;
398 }
399 }
400 }
401
402 public:
403 VerifyStrongCodeRootOopClosure(const HeapRegion* hr):
404 _hr(hr), _failures(false), _has_oops_in_region(false) {}
405
406 void do_oop(narrowOop* p) { do_oop_work(p); }
407 void do_oop(oop* p) { do_oop_work(p); }
408
409 bool failures() { return _failures; }
410 bool has_oops_in_region() { return _has_oops_in_region; }
411 };
412
413 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
414 const HeapRegion* _hr;
415 bool _failures;
416 public:
417 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
418 _hr(hr), _failures(false) {}
419
420 void do_code_blob(CodeBlob* cb) {
421 nmethod* nm = (cb == NULL) ? NULL : cb->as_compiled_method()->as_nmethod_or_null();
422 if (nm != NULL) {
423 // Verify that the nemthod is live
424 if (!nm->is_alive()) {
425 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " PTR_FORMAT " in its strong code roots",
426 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
427 _failures = true;
428 } else {
429 VerifyStrongCodeRootOopClosure oop_cl(_hr);
430 nm->oops_do(&oop_cl);
431 if (!oop_cl.has_oops_in_region()) {
432 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " PTR_FORMAT " in its strong code roots with no pointers into region",
433 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
434 _failures = true;
435 } else if (oop_cl.failures()) {
436 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has other failures for nmethod " PTR_FORMAT,
437 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
438 _failures = true;
439 }
440 }
441 }
442 }
443
444 bool failures() { return _failures; }
445 };
446
447 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
448 if (!G1VerifyHeapRegionCodeRoots) {
449 // We're not verifying code roots.
450 return;
451 }
452 if (vo == VerifyOption_G1UseMarkWord) {
453 // Marking verification during a full GC is performed after class
454 // unloading, code cache unloading, etc so the strong code roots
455 // attached to each heap region are in an inconsistent state. They won't
456 // be consistent until the strong code roots are rebuilt after the
457 // actual GC. Skip verifying the strong code roots in this particular
458 // time.
459 assert(VerifyDuringGC, "only way to get here");
460 return;
461 }
462
463 HeapRegionRemSet* hrrs = rem_set();
464 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
465
466 // if this region is empty then there should be no entries
467 // on its strong code root list
468 if (is_empty()) {
469 if (strong_code_roots_length > 0) {
470 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] is empty but has " SIZE_FORMAT " code root entries",
471 p2i(bottom()), p2i(end()), strong_code_roots_length);
472 *failures = true;
473 }
474 return;
475 }
476
477 if (is_continues_humongous()) {
478 if (strong_code_roots_length > 0) {
479 log_error(gc, verify)("region " HR_FORMAT " is a continuation of a humongous region but has " SIZE_FORMAT " code root entries",
480 HR_FORMAT_PARAMS(this), strong_code_roots_length);
481 *failures = true;
482 }
483 return;
484 }
485
486 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
487 strong_code_roots_do(&cb_cl);
488
489 if (cb_cl.failures()) {
490 *failures = true;
491 }
492 }
493
494 void HeapRegion::print() const { print_on(tty); }
495 void HeapRegion::print_on(outputStream* st) const {
496 st->print("|%4u", this->_hrm_index);
497 st->print("|" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT,
498 p2i(bottom()), p2i(top()), p2i(end()));
499 st->print("|%3d%%", (int) ((double) used() * 100 / capacity()));
500 st->print("|%2s", get_short_type_str());
501 if (in_collection_set()) {
502 st->print("|CS");
503 } else {
504 st->print("| ");
505 }
506 st->print("|TS%3u", _gc_time_stamp);
507 st->print("|AC%3u", allocation_context());
508 st->print_cr("|TAMS " PTR_FORMAT ", " PTR_FORMAT "|",
509 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start()));
510 }
511
512 class G1VerificationClosure : public OopClosure {
513 protected:
514 G1CollectedHeap* _g1h;
515 CardTableModRefBS* _bs;
516 oop _containing_obj;
517 bool _failures;
518 int _n_failures;
519 VerifyOption _vo;
520 public:
521 // _vo == UsePrevMarking -> use "prev" marking information,
522 // _vo == UseNextMarking -> use "next" marking information,
523 // _vo == UseMarkWord -> use mark word from object header.
524 G1VerificationClosure(G1CollectedHeap* g1h, VerifyOption vo) :
525 _g1h(g1h), _bs(barrier_set_cast<CardTableModRefBS>(g1h->barrier_set())),
526 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo) {
527 }
528
529 void set_containing_obj(oop obj) {
530 _containing_obj = obj;
531 }
532
533 bool failures() { return _failures; }
534 int n_failures() { return _n_failures; }
535
536 void print_object(outputStream* out, oop obj) {
537 #ifdef PRODUCT
538 Klass* k = obj->klass();
539 const char* class_name = k->external_name();
540 out->print_cr("class name %s", class_name);
541 #else // PRODUCT
542 obj->print_on(out);
543 #endif // PRODUCT
544 }
545 };
546
547 class VerifyLiveClosure : public G1VerificationClosure {
548 public:
549 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
550 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
551 virtual void do_oop(oop* p) { do_oop_work(p); }
552
553 template <class T>
554 void do_oop_work(T* p) {
555 assert(_containing_obj != NULL, "Precondition");
556 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
557 "Precondition");
558 verify_liveness(p);
559 }
560
561 template <class T>
562 void verify_liveness(T* p) {
563 T heap_oop = oopDesc::load_heap_oop(p);
564 Log(gc, verify) log;
565 if (!oopDesc::is_null(heap_oop)) {
566 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
567 bool failed = false;
568 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
569 MutexLockerEx x(ParGCRareEvent_lock,
570 Mutex::_no_safepoint_check_flag);
571
572 if (!_failures) {
573 log.error("----------");
574 }
575 ResourceMark rm;
576 if (!_g1h->is_in_closed_subset(obj)) {
577 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
578 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
579 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
580 print_object(log.error_stream(), _containing_obj);
581 log.error("points to obj " PTR_FORMAT " not in the heap", p2i(obj));
582 } else {
583 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
584 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
585 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
586 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
587 print_object(log.error_stream(), _containing_obj);
588 log.error("points to dead obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
589 p2i(obj), p2i(to->bottom()), p2i(to->end()));
590 print_object(log.error_stream(), obj);
591 }
592 log.error("----------");
593 _failures = true;
594 failed = true;
595 _n_failures++;
596 }
597 }
598 }
599 };
600
601 class VerifyRemSetClosure : public G1VerificationClosure {
602 public:
603 VerifyRemSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
604 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
605 virtual void do_oop(oop* p) { do_oop_work(p); }
606
607 template <class T>
608 void do_oop_work(T* p) {
609 assert(_containing_obj != NULL, "Precondition");
610 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
611 "Precondition");
612 verify_remembered_set(p);
613 }
614
615 template <class T>
616 void verify_remembered_set(T* p) {
617 T heap_oop = oopDesc::load_heap_oop(p);
618 Log(gc, verify) log;
619 if (!oopDesc::is_null(heap_oop)) {
620 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
621 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
622 HeapRegion* to = _g1h->heap_region_containing(obj);
623 if (from != NULL && to != NULL &&
624 from != to &&
625 !to->is_pinned()) {
626 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
627 jbyte cv_field = *_bs->byte_for_const(p);
628 const jbyte dirty = CardTableModRefBS::dirty_card_val();
629
630 bool is_bad = !(from->is_young()
631 || to->rem_set()->contains_reference(p)
632 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
633 (_containing_obj->is_objArray() ?
634 cv_field == dirty
635 : cv_obj == dirty || cv_field == dirty));
636 if (is_bad) {
637 MutexLockerEx x(ParGCRareEvent_lock,
638 Mutex::_no_safepoint_check_flag);
639
640 if (!_failures) {
641 log.error("----------");
642 }
643 log.error("Missing rem set entry:");
644 log.error("Field " PTR_FORMAT " of obj " PTR_FORMAT ", in region " HR_FORMAT,
645 p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
646 ResourceMark rm;
647 _containing_obj->print_on(log.error_stream());
648 log.error("points to obj " PTR_FORMAT " in region " HR_FORMAT, p2i(obj), HR_FORMAT_PARAMS(to));
649 if (obj->is_oop()) {
650 obj->print_on(log.error_stream());
651 }
652 log.error("Obj head CTE = %d, field CTE = %d.", cv_obj, cv_field);
653 log.error("----------");
654 _failures = true;
655 _n_failures++;
656 }
657 }
658 }
659 }
660 };
661
662 // Closure that applies the given two closures in sequence.
663 class G1Mux2Closure : public OopClosure {
664 OopClosure* _c1;
665 OopClosure* _c2;
666 public:
667 G1Mux2Closure(OopClosure *c1, OopClosure *c2) { _c1 = c1; _c2 = c2; }
668 template <class T> inline void do_oop_work(T* p) {
669 // Apply first closure; then apply the second.
670 _c1->do_oop(p);
671 _c2->do_oop(p);
672 }
673 virtual inline void do_oop(oop* p) { do_oop_work(p); }
674 virtual inline void do_oop(narrowOop* p) { do_oop_work(p); }
675 };
676
677 // This really ought to be commoned up into OffsetTableContigSpace somehow.
678 // We would need a mechanism to make that code skip dead objects.
679
680 void HeapRegion::verify(VerifyOption vo,
681 bool* failures) const {
682 G1CollectedHeap* g1 = G1CollectedHeap::heap();
683 *failures = false;
684 HeapWord* p = bottom();
685 HeapWord* prev_p = NULL;
686 VerifyLiveClosure vl_cl(g1, vo);
687 VerifyRemSetClosure vr_cl(g1, vo);
688 bool is_region_humongous = is_humongous();
689 size_t object_num = 0;
690 while (p < top()) {
691 oop obj = oop(p);
692 size_t obj_size = block_size(p);
693 object_num += 1;
694
695 if (!g1->is_obj_dead_cond(obj, this, vo)) {
696 if (obj->is_oop()) {
697 Klass* klass = obj->klass();
698 bool is_metaspace_object = Metaspace::contains(klass) ||
699 (vo == VerifyOption_G1UsePrevMarking &&
700 ClassLoaderDataGraph::unload_list_contains(klass));
701 if (!is_metaspace_object) {
702 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
703 "not metadata", p2i(klass), p2i(obj));
704 *failures = true;
705 return;
706 } else if (!klass->is_klass()) {
707 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
708 "not a klass", p2i(klass), p2i(obj));
709 *failures = true;
710 return;
711 } else {
712 vl_cl.set_containing_obj(obj);
713 if (!g1->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) {
714 // verify liveness and rem_set
715 vr_cl.set_containing_obj(obj);
716 G1Mux2Closure mux(&vl_cl, &vr_cl);
717 obj->oop_iterate_no_header(&mux);
718
719 if (vr_cl.failures()) {
720 *failures = true;
721 }
722 if (G1MaxVerifyFailures >= 0 &&
723 vr_cl.n_failures() >= G1MaxVerifyFailures) {
724 return;
725 }
726 } else {
727 // verify only liveness
728 obj->oop_iterate_no_header(&vl_cl);
729 }
730 if (vl_cl.failures()) {
731 *failures = true;
732 }
733 if (G1MaxVerifyFailures >= 0 &&
734 vl_cl.n_failures() >= G1MaxVerifyFailures) {
735 return;
736 }
737 }
738 } else {
739 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
740 *failures = true;
741 return;
742 }
743 }
744 prev_p = p;
745 p += obj_size;
746 }
747
748 if (!is_young() && !is_empty()) {
749 _bot_part.verify();
750 }
751
752 if (is_region_humongous) {
753 oop obj = oop(this->humongous_start_region()->bottom());
754 if ((HeapWord*)obj > bottom() || (HeapWord*)obj + obj->size() < bottom()) {
755 log_error(gc, verify)("this humongous region is not part of its' humongous object " PTR_FORMAT, p2i(obj));
756 *failures = true;
757 return;
758 }
759 }
760
761 if (!is_region_humongous && p != top()) {
762 log_error(gc, verify)("end of last object " PTR_FORMAT " "
763 "does not match top " PTR_FORMAT, p2i(p), p2i(top()));
764 *failures = true;
765 return;
766 }
767
768 HeapWord* the_end = end();
769 // Do some extra BOT consistency checking for addresses in the
770 // range [top, end). BOT look-ups in this range should yield
771 // top. No point in doing that if top == end (there's nothing there).
772 if (p < the_end) {
773 // Look up top
774 HeapWord* addr_1 = p;
775 HeapWord* b_start_1 = _bot_part.block_start_const(addr_1);
776 if (b_start_1 != p) {
777 log_error(gc, verify)("BOT look up for top: " PTR_FORMAT " "
778 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
779 p2i(addr_1), p2i(b_start_1), p2i(p));
780 *failures = true;
781 return;
782 }
783
784 // Look up top + 1
785 HeapWord* addr_2 = p + 1;
786 if (addr_2 < the_end) {
787 HeapWord* b_start_2 = _bot_part.block_start_const(addr_2);
788 if (b_start_2 != p) {
789 log_error(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " "
790 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
791 p2i(addr_2), p2i(b_start_2), p2i(p));
792 *failures = true;
793 return;
794 }
795 }
796
797 // Look up an address between top and end
798 size_t diff = pointer_delta(the_end, p) / 2;
799 HeapWord* addr_3 = p + diff;
800 if (addr_3 < the_end) {
801 HeapWord* b_start_3 = _bot_part.block_start_const(addr_3);
802 if (b_start_3 != p) {
803 log_error(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " "
804 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
805 p2i(addr_3), p2i(b_start_3), p2i(p));
806 *failures = true;
807 return;
808 }
809 }
810
811 // Look up end - 1
812 HeapWord* addr_4 = the_end - 1;
813 HeapWord* b_start_4 = _bot_part.block_start_const(addr_4);
814 if (b_start_4 != p) {
815 log_error(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " "
816 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
817 p2i(addr_4), p2i(b_start_4), p2i(p));
818 *failures = true;
819 return;
820 }
821 }
822
823 verify_strong_code_roots(vo, failures);
824 }
825
826 void HeapRegion::verify() const {
827 bool dummy = false;
828 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
829 }
830
831 void HeapRegion::verify_rem_set(VerifyOption vo, bool* failures) const {
832 G1CollectedHeap* g1 = G1CollectedHeap::heap();
833 *failures = false;
834 HeapWord* p = bottom();
835 HeapWord* prev_p = NULL;
836 VerifyRemSetClosure vr_cl(g1, vo);
837 while (p < top()) {
838 oop obj = oop(p);
839 size_t obj_size = block_size(p);
840
841 if (!g1->is_obj_dead_cond(obj, this, vo)) {
842 if (obj->is_oop()) {
843 vr_cl.set_containing_obj(obj);
844 obj->oop_iterate_no_header(&vr_cl);
845
846 if (vr_cl.failures()) {
847 *failures = true;
848 }
849 if (G1MaxVerifyFailures >= 0 &&
850 vr_cl.n_failures() >= G1MaxVerifyFailures) {
851 return;
852 }
853 } else {
854 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
855 *failures = true;
856 return;
857 }
858 }
859
860 prev_p = p;
861 p += obj_size;
862 }
863 }
864
865 void HeapRegion::verify_rem_set() const {
866 bool failures = false;
867 verify_rem_set(VerifyOption_G1UsePrevMarking, &failures);
868 guarantee(!failures, "HeapRegion RemSet verification failed");
869 }
870
871 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
872 scan_and_forward(this, cp);
873 }
874
875 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
876 // away eventually.
877
878 void G1ContiguousSpace::clear(bool mangle_space) {
879 set_top(bottom());
880 _scan_top = bottom();
881 CompactibleSpace::clear(mangle_space);
882 reset_bot();
883 }
884
885 #ifndef PRODUCT
886 void G1ContiguousSpace::mangle_unused_area() {
887 mangle_unused_area_complete();
888 }
889
890 void G1ContiguousSpace::mangle_unused_area_complete() {
891 SpaceMangler::mangle_region(MemRegion(top(), end()));
892 }
893 #endif
894
895 void G1ContiguousSpace::print() const {
896 print_short();
897 tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
898 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
899 p2i(bottom()), p2i(top()), p2i(_bot_part.threshold()), p2i(end()));
900 }
901
902 HeapWord* G1ContiguousSpace::initialize_threshold() {
903 return _bot_part.initialize_threshold();
904 }
905
906 HeapWord* G1ContiguousSpace::cross_threshold(HeapWord* start,
907 HeapWord* end) {
908 _bot_part.alloc_block(start, end);
909 return _bot_part.threshold();
910 }
911
912 HeapWord* G1ContiguousSpace::scan_top() const {
913 G1CollectedHeap* g1h = G1CollectedHeap::heap();
914 HeapWord* local_top = top();
915 OrderAccess::loadload();
916 const unsigned local_time_stamp = _gc_time_stamp;
917 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
918 if (local_time_stamp < g1h->get_gc_time_stamp()) {
919 return local_top;
920 } else {
921 return _scan_top;
922 }
923 }
924
925 void G1ContiguousSpace::record_timestamp() {
926 G1CollectedHeap* g1h = G1CollectedHeap::heap();
927 uint curr_gc_time_stamp = g1h->get_gc_time_stamp();
928
929 if (_gc_time_stamp < curr_gc_time_stamp) {
930 // Setting the time stamp here tells concurrent readers to look at
931 // scan_top to know the maximum allowed address to look at.
932
933 // scan_top should be bottom for all regions except for the
934 // retained old alloc region which should have scan_top == top
935 HeapWord* st = _scan_top;
936 guarantee(st == _bottom || st == _top, "invariant");
937
938 _gc_time_stamp = curr_gc_time_stamp;
939 }
940 }
941
942 void G1ContiguousSpace::record_retained_region() {
943 // scan_top is the maximum address where it's safe for the next gc to
944 // scan this region.
945 _scan_top = top();
946 }
947
948 void G1ContiguousSpace::safe_object_iterate(ObjectClosure* blk) {
949 object_iterate(blk);
950 }
951
952 void G1ContiguousSpace::object_iterate(ObjectClosure* blk) {
953 HeapWord* p = bottom();
954 while (p < top()) {
955 if (block_is_obj(p)) {
956 blk->do_object(oop(p));
957 }
958 p += block_size(p);
959 }
960 }
961
962 G1ContiguousSpace::G1ContiguousSpace(G1BlockOffsetTable* bot) :
963 _bot_part(bot, this),
964 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
965 _gc_time_stamp(0)
966 {
967 }
968
969 void G1ContiguousSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
970 CompactibleSpace::initialize(mr, clear_space, mangle_space);
971 _top = bottom();
972 _scan_top = bottom();
973 set_saved_mark_word(NULL);
974 reset_bot();
975 }
976