1 /*
2 * Copyright (c) 2001, 2016, 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 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 if (G1HeapRegionSize != GrainBytes) {
158 FLAG_SET_ERGO(size_t, G1HeapRegionSize, GrainBytes);
159 }
160 }
161
162 void HeapRegion::reset_after_compaction() {
163 G1ContiguousSpace::reset_after_compaction();
164 // After a compaction the mark bitmap is invalid, so we must
165 // treat all objects as being inside the unmarked area.
166 zero_marked_bytes();
167 init_top_at_mark_start();
168 }
169
170 void HeapRegion::hr_clear(bool keep_remset, bool clear_space, bool locked) {
171 assert(_humongous_start_region == NULL,
172 "we should have already filtered out humongous regions");
173 assert(!in_collection_set(),
174 "Should not clear heap region %u in the collection set", hrm_index());
175
176 set_allocation_context(AllocationContext::system());
177 set_young_index_in_cset(-1);
178 uninstall_surv_rate_group();
179 set_free();
180 reset_pre_dummy_top();
181
182 if (!keep_remset) {
183 if (locked) {
184 rem_set()->clear_locked();
185 } else {
186 rem_set()->clear();
187 }
188 }
189
190 zero_marked_bytes();
191
192 init_top_at_mark_start();
193 _gc_time_stamp = G1CollectedHeap::heap()->get_gc_time_stamp();
194 if (clear_space) clear(SpaceDecorator::Mangle);
195 }
196
197 void HeapRegion::par_clear() {
198 assert(used() == 0, "the region should have been already cleared");
199 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
200 HeapRegionRemSet* hrrs = rem_set();
201 hrrs->clear();
202 CardTableModRefBS* ct_bs =
203 barrier_set_cast<CardTableModRefBS>(G1CollectedHeap::heap()->barrier_set());
204 ct_bs->clear(MemRegion(bottom(), end()));
205 }
206
207 void HeapRegion::calc_gc_efficiency() {
208 // GC efficiency is the ratio of how much space would be
209 // reclaimed over how long we predict it would take to reclaim it.
210 G1CollectedHeap* g1h = G1CollectedHeap::heap();
211 G1Policy* g1p = g1h->g1_policy();
212
213 // Retrieve a prediction of the elapsed time for this region for
214 // a mixed gc because the region will only be evacuated during a
215 // mixed gc.
216 double region_elapsed_time_ms =
217 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
218 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
219 }
220
221 void HeapRegion::set_free() {
222 report_region_type_change(G1HeapRegionTraceType::Free);
223 _type.set_free();
224 }
225
226 void HeapRegion::set_eden() {
227 report_region_type_change(G1HeapRegionTraceType::Eden);
228 _type.set_eden();
229 }
230
231 void HeapRegion::set_eden_pre_gc() {
232 report_region_type_change(G1HeapRegionTraceType::Eden);
233 _type.set_eden_pre_gc();
234 }
235
236 void HeapRegion::set_survivor() {
237 report_region_type_change(G1HeapRegionTraceType::Survivor);
238 _type.set_survivor();
239 }
240
241 void HeapRegion::set_old() {
242 report_region_type_change(G1HeapRegionTraceType::Old);
243 _type.set_old();
244 }
245
246 void HeapRegion::set_archive() {
247 report_region_type_change(G1HeapRegionTraceType::Archive);
248 _type.set_archive();
249 }
250
251 void HeapRegion::set_starts_humongous(HeapWord* obj_top, size_t fill_size) {
252 assert(!is_humongous(), "sanity / pre-condition");
253 assert(top() == bottom(), "should be empty");
254
255 report_region_type_change(G1HeapRegionTraceType::StartsHumongous);
256 _type.set_starts_humongous();
257 _humongous_start_region = this;
258
259 _bot_part.set_for_starts_humongous(obj_top, fill_size);
260 }
261
262 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) {
263 assert(!is_humongous(), "sanity / pre-condition");
264 assert(top() == bottom(), "should be empty");
265 assert(first_hr->is_starts_humongous(), "pre-condition");
266
267 report_region_type_change(G1HeapRegionTraceType::ContinuesHumongous);
268 _type.set_continues_humongous();
269 _humongous_start_region = first_hr;
270 }
271
272 void HeapRegion::clear_humongous() {
273 assert(is_humongous(), "pre-condition");
274
275 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
276 _humongous_start_region = NULL;
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 _predicted_bytes_to_copy(0)
295 {
296 _rem_set = new HeapRegionRemSet(bot, this);
297
298 initialize(mr);
299 }
300
301 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
302 assert(_rem_set->is_empty(), "Remembered set must be empty");
303
304 G1ContiguousSpace::initialize(mr, clear_space, mangle_space);
305
306 hr_clear(false /*par*/, false /*clear_space*/);
307 set_top(bottom());
308 record_timestamp();
309 }
310
311 void HeapRegion::report_region_type_change(G1HeapRegionTraceType::Type to) {
312 HeapRegionTracer::send_region_type_change(_hrm_index,
313 get_trace_type(),
314 to,
315 (uintptr_t)bottom(),
316 used(),
317 (uint)allocation_context());
318 }
319
320 CompactibleSpace* HeapRegion::next_compaction_space() const {
321 return G1CollectedHeap::heap()->next_compaction_region(this);
322 }
323
324 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
325 bool during_conc_mark) {
326 // We always recreate the prev marking info and we'll explicitly
327 // mark all objects we find to be self-forwarded on the prev
328 // bitmap. So all objects need to be below PTAMS.
329 _prev_marked_bytes = 0;
330
331 if (during_initial_mark) {
332 // During initial-mark, we'll also explicitly mark all objects
333 // we find to be self-forwarded on the next bitmap. So all
334 // objects need to be below NTAMS.
335 _next_top_at_mark_start = top();
336 _next_marked_bytes = 0;
337 } else if (during_conc_mark) {
338 // During concurrent mark, all objects in the CSet (including
339 // the ones we find to be self-forwarded) are implicitly live.
340 // So all objects need to be above NTAMS.
341 _next_top_at_mark_start = bottom();
342 _next_marked_bytes = 0;
343 }
344 }
345
346 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
347 bool during_conc_mark,
348 size_t marked_bytes) {
349 assert(marked_bytes <= used(),
350 "marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used());
351 _prev_top_at_mark_start = top();
352 _prev_marked_bytes = marked_bytes;
353 }
354
355 bool HeapRegion::oops_on_card_seq_iterate_careful(MemRegion mr,
356 FilterOutOfRegionClosure* cl,
357 jbyte* card_ptr) {
358 assert(card_ptr != NULL, "pre-condition");
359 G1CollectedHeap* g1h = G1CollectedHeap::heap();
360
361 // If we're within a stop-world GC, then we might look at a card in a
362 // GC alloc region that extends onto a GC LAB, which may not be
363 // parseable. Stop such at the "scan_top" of the region.
364 if (g1h->is_gc_active()) {
365 mr = mr.intersection(MemRegion(bottom(), scan_top()));
366 } else {
367 mr = mr.intersection(used_region());
368 }
369 if (mr.is_empty()) return true;
370 // Otherwise, find the obj that extends onto mr.start().
371
372 // The intersection of the incoming mr (for the card) and the
373 // allocated part of the region is non-empty. This implies that
374 // we have actually allocated into this region. The code in
375 // G1CollectedHeap.cpp that allocates a new region sets the
376 // is_young tag on the region before allocating. Thus we
377 // safely know if this region is young.
378 if (is_young()) {
379 return true;
380 }
381
382 // We can only clean the card here, after we make the decision that
383 // the card is not young.
384 *card_ptr = CardTableModRefBS::clean_card_val();
385 // We must complete this write before we do any of the reads below.
386 OrderAccess::storeload();
387
388 // Cache the boundaries of the memory region in some const locals
389 HeapWord* const start = mr.start();
390 HeapWord* const end = mr.end();
391
392 // Update BOT as needed while finding start of (potential) object.
393 HeapWord* cur = block_start(start);
394 assert(cur <= start, "Postcondition");
395
396 oop obj;
397
398 HeapWord* next = cur;
399 do {
400 cur = next;
401 obj = oop(cur);
402 if (obj->klass_or_null() == NULL) {
403 // Ran into an unparseable point.
404 assert(!g1h->is_gc_active(),
405 "Unparsable heap during GC at " PTR_FORMAT, p2i(cur));
406 return false;
407 }
408 // Otherwise...
409 next = cur + block_size(cur);
410 } while (next <= start);
411
412 // If we finish the above loop...We have a parseable object that
413 // begins on or before the start of the memory region, and ends
414 // inside or spans the entire region.
415 assert(cur <= start, "Loop postcondition");
416 assert(obj->klass_or_null() != NULL, "Loop postcondition");
417
418 do {
419 obj = oop(cur);
420 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant");
421 if (obj->klass_or_null() == NULL) {
422 // Ran into an unparseable point.
423 assert(!g1h->is_gc_active(),
424 "Unparsable heap during GC at " PTR_FORMAT, p2i(cur));
425 return false;
426 }
427
428 // Advance the current pointer. "obj" still points to the object to iterate.
429 cur = cur + block_size(cur);
430
431 if (!g1h->is_obj_dead(obj)) {
432 // Non-objArrays are sometimes marked imprecise at the object start. We
433 // always need to iterate over them in full.
434 // We only iterate over object arrays in full if they are completely contained
435 // in the memory region.
436 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) {
437 obj->oop_iterate(cl);
438 } else {
439 obj->oop_iterate(cl, mr);
440 }
441 }
442 } while (cur < end);
443
444 return true;
445 }
446
447 // Code roots support
448
449 void HeapRegion::add_strong_code_root(nmethod* nm) {
450 HeapRegionRemSet* hrrs = rem_set();
451 hrrs->add_strong_code_root(nm);
452 }
453
454 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
455 assert_locked_or_safepoint(CodeCache_lock);
456 HeapRegionRemSet* hrrs = rem_set();
457 hrrs->add_strong_code_root_locked(nm);
458 }
459
460 void HeapRegion::remove_strong_code_root(nmethod* nm) {
461 HeapRegionRemSet* hrrs = rem_set();
462 hrrs->remove_strong_code_root(nm);
463 }
464
465 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
466 HeapRegionRemSet* hrrs = rem_set();
467 hrrs->strong_code_roots_do(blk);
468 }
469
470 class VerifyStrongCodeRootOopClosure: public OopClosure {
471 const HeapRegion* _hr;
472 nmethod* _nm;
473 bool _failures;
474 bool _has_oops_in_region;
475
476 template <class T> void do_oop_work(T* p) {
477 T heap_oop = oopDesc::load_heap_oop(p);
478 if (!oopDesc::is_null(heap_oop)) {
479 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
480
481 // Note: not all the oops embedded in the nmethod are in the
482 // current region. We only look at those which are.
483 if (_hr->is_in(obj)) {
484 // Object is in the region. Check that its less than top
485 if (_hr->top() <= (HeapWord*)obj) {
486 // Object is above top
487 log_error(gc, verify)("Object " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ") is above top " PTR_FORMAT,
488 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top()));
489 _failures = true;
490 return;
491 }
492 // Nmethod has at least one oop in the current region
493 _has_oops_in_region = true;
494 }
495 }
496 }
497
498 public:
499 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
500 _hr(hr), _failures(false), _has_oops_in_region(false) {}
501
502 void do_oop(narrowOop* p) { do_oop_work(p); }
503 void do_oop(oop* p) { do_oop_work(p); }
504
505 bool failures() { return _failures; }
506 bool has_oops_in_region() { return _has_oops_in_region; }
507 };
508
509 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
510 const HeapRegion* _hr;
511 bool _failures;
512 public:
513 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
514 _hr(hr), _failures(false) {}
515
516 void do_code_blob(CodeBlob* cb) {
517 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
518 if (nm != NULL) {
519 // Verify that the nemthod is live
520 if (!nm->is_alive()) {
521 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " PTR_FORMAT " in its strong code roots",
522 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
523 _failures = true;
524 } else {
525 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
526 nm->oops_do(&oop_cl);
527 if (!oop_cl.has_oops_in_region()) {
528 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " PTR_FORMAT " in its strong code roots with no pointers into region",
529 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
530 _failures = true;
531 } else if (oop_cl.failures()) {
532 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has other failures for nmethod " PTR_FORMAT,
533 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
534 _failures = true;
535 }
536 }
537 }
538 }
539
540 bool failures() { return _failures; }
541 };
542
543 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
544 if (!G1VerifyHeapRegionCodeRoots) {
545 // We're not verifying code roots.
546 return;
547 }
548 if (vo == VerifyOption_G1UseMarkWord) {
549 // Marking verification during a full GC is performed after class
550 // unloading, code cache unloading, etc so the strong code roots
551 // attached to each heap region are in an inconsistent state. They won't
552 // be consistent until the strong code roots are rebuilt after the
553 // actual GC. Skip verifying the strong code roots in this particular
554 // time.
555 assert(VerifyDuringGC, "only way to get here");
556 return;
557 }
558
559 HeapRegionRemSet* hrrs = rem_set();
560 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
561
562 // if this region is empty then there should be no entries
563 // on its strong code root list
564 if (is_empty()) {
565 if (strong_code_roots_length > 0) {
566 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] is empty but has " SIZE_FORMAT " code root entries",
567 p2i(bottom()), p2i(end()), strong_code_roots_length);
568 *failures = true;
569 }
570 return;
571 }
572
573 if (is_continues_humongous()) {
574 if (strong_code_roots_length > 0) {
575 log_error(gc, verify)("region " HR_FORMAT " is a continuation of a humongous region but has " SIZE_FORMAT " code root entries",
576 HR_FORMAT_PARAMS(this), strong_code_roots_length);
577 *failures = true;
578 }
579 return;
580 }
581
582 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
583 strong_code_roots_do(&cb_cl);
584
585 if (cb_cl.failures()) {
586 *failures = true;
587 }
588 }
589
590 void HeapRegion::print() const { print_on(tty); }
591 void HeapRegion::print_on(outputStream* st) const {
592 st->print("|%4u", this->_hrm_index);
593 st->print("|" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT,
594 p2i(bottom()), p2i(top()), p2i(end()));
595 st->print("|%3d%%", (int) ((double) used() * 100 / capacity()));
596 st->print("|%2s", get_short_type_str());
597 if (in_collection_set()) {
598 st->print("|CS");
599 } else {
600 st->print("| ");
601 }
602 st->print("|TS%3u", _gc_time_stamp);
603 st->print("|AC%3u", allocation_context());
604 st->print_cr("|TAMS " PTR_FORMAT ", " PTR_FORMAT "|",
605 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start()));
606 }
607
608 class G1VerificationClosure : 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 G1VerificationClosure(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
643 class VerifyLiveClosure : public G1VerificationClosure {
644 public:
645 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
646 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
647 virtual void do_oop(oop* p) { do_oop_work(p); }
648
649 template <class T>
650 void do_oop_work(T* p) {
651 assert(_containing_obj != NULL, "Precondition");
652 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
653 "Precondition");
654 verify_liveness(p);
655 }
656
657 template <class T>
658 void verify_liveness(T* p) {
659 T heap_oop = oopDesc::load_heap_oop(p);
660 Log(gc, verify) log;
661 if (!oopDesc::is_null(heap_oop)) {
662 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
663 bool failed = false;
664 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
665 MutexLockerEx x(ParGCRareEvent_lock,
666 Mutex::_no_safepoint_check_flag);
667
668 if (!_failures) {
669 log.error("----------");
670 }
671 ResourceMark rm;
672 if (!_g1h->is_in_closed_subset(obj)) {
673 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
674 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
675 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
676 print_object(log.error_stream(), _containing_obj);
677 log.error("points to obj " PTR_FORMAT " not in the heap", p2i(obj));
678 } else {
679 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
680 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
681 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
682 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
683 print_object(log.error_stream(), _containing_obj);
684 log.error("points to dead obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
685 p2i(obj), p2i(to->bottom()), p2i(to->end()));
686 print_object(log.error_stream(), obj);
687 }
688 log.error("----------");
689 _failures = true;
690 failed = true;
691 _n_failures++;
692 }
693 }
694 }
695 };
696
697 class VerifyRemSetClosure : public G1VerificationClosure {
698 public:
699 VerifyRemSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
700 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
701 virtual void do_oop(oop* p) { do_oop_work(p); }
702
703 template <class T>
704 void do_oop_work(T* p) {
705 assert(_containing_obj != NULL, "Precondition");
706 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
707 "Precondition");
708 verify_remembered_set(p);
709 }
710
711 template <class T>
712 void verify_remembered_set(T* p) {
713 T heap_oop = oopDesc::load_heap_oop(p);
714 Log(gc, verify) log;
715 if (!oopDesc::is_null(heap_oop)) {
716 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
717 bool failed = false;
718 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
719 HeapRegion* to = _g1h->heap_region_containing(obj);
720 if (from != NULL && to != NULL &&
721 from != to &&
722 !to->is_pinned()) {
723 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
724 jbyte cv_field = *_bs->byte_for_const(p);
725 const jbyte dirty = CardTableModRefBS::dirty_card_val();
726
727 bool is_bad = !(from->is_young()
728 || to->rem_set()->contains_reference(p)
729 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
730 (_containing_obj->is_objArray() ?
731 cv_field == dirty
732 : cv_obj == dirty || cv_field == dirty));
733 if (is_bad) {
734 MutexLockerEx x(ParGCRareEvent_lock,
735 Mutex::_no_safepoint_check_flag);
736
737 if (!_failures) {
738 log.error("----------");
739 }
740 log.error("Missing rem set entry:");
741 log.error("Field " PTR_FORMAT " of obj " PTR_FORMAT ", in region " HR_FORMAT,
742 p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
743 ResourceMark rm;
744 _containing_obj->print_on(log.error_stream());
745 log.error("points to obj " PTR_FORMAT " in region " HR_FORMAT, p2i(obj), HR_FORMAT_PARAMS(to));
746 if (obj->is_oop()) {
747 obj->print_on(log.error_stream());
748 }
749 log.error("Obj head CTE = %d, field CTE = %d.", cv_obj, cv_field);
750 log.error("----------");
751 _failures = true;
752 if (!failed) _n_failures++;
753 }
754 }
755 }
756 }
757 };
758
759 // This really ought to be commoned up into OffsetTableContigSpace somehow.
760 // We would need a mechanism to make that code skip dead objects.
761
762 void HeapRegion::verify(VerifyOption vo,
763 bool* failures) const {
764 G1CollectedHeap* g1 = G1CollectedHeap::heap();
765 *failures = false;
766 HeapWord* p = bottom();
767 HeapWord* prev_p = NULL;
768 VerifyLiveClosure vl_cl(g1, vo);
769 VerifyRemSetClosure vr_cl(g1, vo);
770 bool is_region_humongous = is_humongous();
771 size_t object_num = 0;
772 while (p < top()) {
773 oop obj = oop(p);
774 size_t obj_size = block_size(p);
775 object_num += 1;
776
777 if (!g1->is_obj_dead_cond(obj, this, vo)) {
778 if (obj->is_oop()) {
779 Klass* klass = obj->klass();
780 bool is_metaspace_object = Metaspace::contains(klass) ||
781 (vo == VerifyOption_G1UsePrevMarking &&
782 ClassLoaderDataGraph::unload_list_contains(klass));
783 if (!is_metaspace_object) {
784 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
785 "not metadata", p2i(klass), p2i(obj));
786 *failures = true;
787 return;
788 } else if (!klass->is_klass()) {
789 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
790 "not a klass", p2i(klass), p2i(obj));
791 *failures = true;
792 return;
793 } else {
794 vl_cl.set_containing_obj(obj);
795 if (!g1->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) {
796 // verify liveness and rem_set
797 vr_cl.set_containing_obj(obj);
798 G1Mux2Closure mux(&vl_cl, &vr_cl);
799 obj->oop_iterate_no_header(&mux);
800
801 if (vr_cl.failures()) {
802 *failures = true;
803 }
804 if (G1MaxVerifyFailures >= 0 &&
805 vr_cl.n_failures() >= G1MaxVerifyFailures) {
806 return;
807 }
808 } else {
809 // verify only liveness
810 obj->oop_iterate_no_header(&vl_cl);
811 }
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 log_error(gc, verify)(PTR_FORMAT " not 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 _bot_part.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 log_error(gc, verify)("this humongous region is not part of its' humongous object " PTR_FORMAT, p2i(obj));
838 *failures = true;
839 return;
840 }
841 }
842
843 if (!is_region_humongous && p != top()) {
844 log_error(gc, verify)("end of last object " PTR_FORMAT " "
845 "does not match top " PTR_FORMAT, p2i(p), p2i(top()));
846 *failures = true;
847 return;
848 }
849
850 HeapWord* the_end = end();
851 // Do some extra BOT consistency checking for addresses in the
852 // range [top, end). BOT look-ups in this range should yield
853 // top. No point in doing that if top == end (there's nothing there).
854 if (p < the_end) {
855 // Look up top
856 HeapWord* addr_1 = p;
857 HeapWord* b_start_1 = _bot_part.block_start_const(addr_1);
858 if (b_start_1 != p) {
859 log_error(gc, verify)("BOT look up for top: " PTR_FORMAT " "
860 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
861 p2i(addr_1), p2i(b_start_1), p2i(p));
862 *failures = true;
863 return;
864 }
865
866 // Look up top + 1
867 HeapWord* addr_2 = p + 1;
868 if (addr_2 < the_end) {
869 HeapWord* b_start_2 = _bot_part.block_start_const(addr_2);
870 if (b_start_2 != p) {
871 log_error(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " "
872 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
873 p2i(addr_2), p2i(b_start_2), p2i(p));
874 *failures = true;
875 return;
876 }
877 }
878
879 // Look up an address between top and end
880 size_t diff = pointer_delta(the_end, p) / 2;
881 HeapWord* addr_3 = p + diff;
882 if (addr_3 < the_end) {
883 HeapWord* b_start_3 = _bot_part.block_start_const(addr_3);
884 if (b_start_3 != p) {
885 log_error(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " "
886 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
887 p2i(addr_3), p2i(b_start_3), p2i(p));
888 *failures = true;
889 return;
890 }
891 }
892
893 // Look up end - 1
894 HeapWord* addr_4 = the_end - 1;
895 HeapWord* b_start_4 = _bot_part.block_start_const(addr_4);
896 if (b_start_4 != p) {
897 log_error(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " "
898 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
899 p2i(addr_4), p2i(b_start_4), p2i(p));
900 *failures = true;
901 return;
902 }
903 }
904
905 verify_strong_code_roots(vo, failures);
906 }
907
908 void HeapRegion::verify() const {
909 bool dummy = false;
910 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
911 }
912
913 void HeapRegion::verify_rem_set(VerifyOption vo, bool* failures) const {
914 G1CollectedHeap* g1 = G1CollectedHeap::heap();
915 *failures = false;
916 HeapWord* p = bottom();
917 HeapWord* prev_p = NULL;
918 VerifyRemSetClosure vr_cl(g1, vo);
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 vr_cl.set_containing_obj(obj);
926 obj->oop_iterate_no_header(&vr_cl);
927
928 if (vr_cl.failures()) {
929 *failures = true;
930 }
931 if (G1MaxVerifyFailures >= 0 &&
932 vr_cl.n_failures() >= G1MaxVerifyFailures) {
933 return;
934 }
935 } else {
936 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
937 *failures = true;
938 return;
939 }
940 }
941
942 prev_p = p;
943 p += obj_size;
944 }
945 }
946
947 void HeapRegion::verify_rem_set() const {
948 bool failures = false;
949 verify_rem_set(VerifyOption_G1UsePrevMarking, &failures);
950 guarantee(!failures, "HeapRegion RemSet verification failed");
951 }
952
953 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
954 scan_and_forward(this, cp);
955 }
956
957 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
958 // away eventually.
959
960 void G1ContiguousSpace::clear(bool mangle_space) {
961 set_top(bottom());
962 _scan_top = bottom();
963 CompactibleSpace::clear(mangle_space);
964 reset_bot();
965 }
966
967 #ifndef PRODUCT
968 void G1ContiguousSpace::mangle_unused_area() {
969 mangle_unused_area_complete();
970 }
971
972 void G1ContiguousSpace::mangle_unused_area_complete() {
973 SpaceMangler::mangle_region(MemRegion(top(), end()));
974 }
975 #endif
976
977 void G1ContiguousSpace::print() const {
978 print_short();
979 tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
980 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
981 p2i(bottom()), p2i(top()), p2i(_bot_part.threshold()), p2i(end()));
982 }
983
984 HeapWord* G1ContiguousSpace::initialize_threshold() {
985 return _bot_part.initialize_threshold();
986 }
987
988 HeapWord* G1ContiguousSpace::cross_threshold(HeapWord* start,
989 HeapWord* end) {
990 _bot_part.alloc_block(start, end);
991 return _bot_part.threshold();
992 }
993
994 HeapWord* G1ContiguousSpace::scan_top() const {
995 G1CollectedHeap* g1h = G1CollectedHeap::heap();
996 HeapWord* local_top = top();
997 OrderAccess::loadload();
998 const unsigned local_time_stamp = _gc_time_stamp;
999 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
1000 if (local_time_stamp < g1h->get_gc_time_stamp()) {
1001 return local_top;
1002 } else {
1003 return _scan_top;
1004 }
1005 }
1006
1007 void G1ContiguousSpace::record_timestamp() {
1008 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1009 uint curr_gc_time_stamp = g1h->get_gc_time_stamp();
1010
1011 if (_gc_time_stamp < curr_gc_time_stamp) {
1012 // Setting the time stamp here tells concurrent readers to look at
1013 // scan_top to know the maximum allowed address to look at.
1014
1015 // scan_top should be bottom for all regions except for the
1016 // retained old alloc region which should have scan_top == top
1017 HeapWord* st = _scan_top;
1018 guarantee(st == _bottom || st == _top, "invariant");
1019
1020 _gc_time_stamp = curr_gc_time_stamp;
1021 }
1022 }
1023
1024 void G1ContiguousSpace::record_retained_region() {
1025 // scan_top is the maximum address where it's safe for the next gc to
1026 // scan this region.
1027 _scan_top = top();
1028 }
1029
1030 void G1ContiguousSpace::safe_object_iterate(ObjectClosure* blk) {
1031 object_iterate(blk);
1032 }
1033
1034 void G1ContiguousSpace::object_iterate(ObjectClosure* blk) {
1035 HeapWord* p = bottom();
1036 while (p < top()) {
1037 if (block_is_obj(p)) {
1038 blk->do_object(oop(p));
1039 }
1040 p += block_size(p);
1041 }
1042 }
1043
1044 G1ContiguousSpace::G1ContiguousSpace(G1BlockOffsetTable* bot) :
1045 _bot_part(bot, this),
1046 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
1047 _gc_time_stamp(0)
1048 {
1049 }
1050
1051 void G1ContiguousSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
1052 CompactibleSpace::initialize(mr, clear_space, mangle_space);
1053 _top = bottom();
1054 _scan_top = bottom();
1055 set_saved_mark_word(NULL);
1056 reset_bot();
1057 }
1058