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.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 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 HeapWord*
356 HeapRegion::object_iterate_mem_careful(MemRegion mr,
357 ObjectClosure* cl) {
358 G1CollectedHeap* g1h = G1CollectedHeap::heap();
359 // We used to use "block_start_careful" here. But we're actually happy
360 // to update the BOT while we do this...
361 HeapWord* cur = block_start(mr.start());
362 mr = mr.intersection(used_region());
363 if (mr.is_empty()) return NULL;
364 // Otherwise, find the obj that extends onto mr.start().
365
366 assert(cur <= mr.start()
367 && (oop(cur)->klass_or_null() == NULL ||
368 cur + oop(cur)->size() > mr.start()),
369 "postcondition of block_start");
370 oop obj;
371 while (cur < mr.end()) {
372 obj = oop(cur);
373 if (obj->klass_or_null() == NULL) {
374 // Ran into an unparseable point.
375 return cur;
376 } else if (!g1h->is_obj_dead(obj)) {
377 cl->do_object(obj);
378 }
379 cur += block_size(cur);
380 }
381 return NULL;
382 }
383
384 HeapWord*
385 HeapRegion::
386 oops_on_card_seq_iterate_careful(MemRegion mr,
387 FilterOutOfRegionClosure* cl,
388 bool filter_young,
389 jbyte* card_ptr) {
390 // Currently, we should only have to clean the card if filter_young
391 // is true and vice versa.
392 if (filter_young) {
393 assert(card_ptr != NULL, "pre-condition");
394 } else {
395 assert(card_ptr == NULL, "pre-condition");
396 }
397 G1CollectedHeap* g1h = G1CollectedHeap::heap();
398
399 // If we're within a stop-world GC, then we might look at a card in a
400 // GC alloc region that extends onto a GC LAB, which may not be
401 // parseable. Stop such at the "scan_top" of the region.
402 if (g1h->is_gc_active()) {
403 mr = mr.intersection(MemRegion(bottom(), scan_top()));
404 } else {
405 mr = mr.intersection(used_region());
406 }
407 if (mr.is_empty()) return NULL;
408 // Otherwise, find the obj that extends onto mr.start().
409
410 // The intersection of the incoming mr (for the card) and the
411 // allocated part of the region is non-empty. This implies that
412 // we have actually allocated into this region. The code in
413 // G1CollectedHeap.cpp that allocates a new region sets the
414 // is_young tag on the region before allocating. Thus we
415 // safely know if this region is young.
416 if (is_young() && filter_young) {
417 return NULL;
418 }
419
420 assert(!is_young(), "check value of filter_young");
421
422 // We can only clean the card here, after we make the decision that
423 // the card is not young. And we only clean the card if we have been
424 // asked to (i.e., card_ptr != NULL).
425 if (card_ptr != NULL) {
426 *card_ptr = CardTableModRefBS::clean_card_val();
427 // We must complete this write before we do any of the reads below.
428 OrderAccess::storeload();
429 }
430
431 // Cache the boundaries of the memory region in some const locals
432 HeapWord* const start = mr.start();
433 HeapWord* const end = mr.end();
434
435 // We used to use "block_start_careful" here. But we're actually happy
436 // to update the BOT while we do this...
437 HeapWord* cur = block_start(start);
438 assert(cur <= start, "Postcondition");
439
440 oop obj;
441
442 HeapWord* next = cur;
443 do {
444 cur = next;
445 obj = oop(cur);
446 if (obj->klass_or_null() == NULL) {
447 // Ran into an unparseable point.
448 return cur;
449 }
450 // Otherwise...
451 next = cur + block_size(cur);
452 } while (next <= start);
453
454 // If we finish the above loop...We have a parseable object that
455 // begins on or before the start of the memory region, and ends
456 // inside or spans the entire region.
457 assert(cur <= start, "Loop postcondition");
458 assert(obj->klass_or_null() != NULL, "Loop postcondition");
459
460 do {
461 obj = oop(cur);
462 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant");
463 if (obj->klass_or_null() == NULL) {
464 // Ran into an unparseable point.
465 return cur;
466 }
467
468 // Advance the current pointer. "obj" still points to the object to iterate.
469 cur = cur + block_size(cur);
470
471 if (!g1h->is_obj_dead(obj)) {
472 // Non-objArrays are sometimes marked imprecise at the object start. We
473 // always need to iterate over them in full.
474 // We only iterate over object arrays in full if they are completely contained
475 // in the memory region.
476 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) {
477 obj->oop_iterate(cl);
478 } else {
479 obj->oop_iterate(cl, mr);
480 }
481 }
482 } while (cur < end);
483
484 return NULL;
485 }
486
487 // Code roots support
488
489 void HeapRegion::add_strong_code_root(nmethod* nm) {
490 HeapRegionRemSet* hrrs = rem_set();
491 hrrs->add_strong_code_root(nm);
492 }
493
494 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
495 assert_locked_or_safepoint(CodeCache_lock);
496 HeapRegionRemSet* hrrs = rem_set();
497 hrrs->add_strong_code_root_locked(nm);
498 }
499
500 void HeapRegion::remove_strong_code_root(nmethod* nm) {
501 HeapRegionRemSet* hrrs = rem_set();
502 hrrs->remove_strong_code_root(nm);
503 }
504
505 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
506 HeapRegionRemSet* hrrs = rem_set();
507 hrrs->strong_code_roots_do(blk);
508 }
509
510 class VerifyStrongCodeRootOopClosure: public OopClosure {
511 const HeapRegion* _hr;
512 nmethod* _nm;
513 bool _failures;
514 bool _has_oops_in_region;
515
516 template <class T> void do_oop_work(T* p) {
517 T heap_oop = oopDesc::load_heap_oop(p);
518 if (!oopDesc::is_null(heap_oop)) {
519 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
520
521 // Note: not all the oops embedded in the nmethod are in the
522 // current region. We only look at those which are.
523 if (_hr->is_in(obj)) {
524 // Object is in the region. Check that its less than top
525 if (_hr->top() <= (HeapWord*)obj) {
526 // Object is above top
527 log_error(gc, verify)("Object " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ") is above top " PTR_FORMAT,
528 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top()));
529 _failures = true;
530 return;
531 }
532 // Nmethod has at least one oop in the current region
533 _has_oops_in_region = true;
534 }
535 }
536 }
537
538 public:
539 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
540 _hr(hr), _failures(false), _has_oops_in_region(false) {}
541
542 void do_oop(narrowOop* p) { do_oop_work(p); }
543 void do_oop(oop* p) { do_oop_work(p); }
544
545 bool failures() { return _failures; }
546 bool has_oops_in_region() { return _has_oops_in_region; }
547 };
548
549 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
550 const HeapRegion* _hr;
551 bool _failures;
552 public:
553 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
554 _hr(hr), _failures(false) {}
555
556 void do_code_blob(CodeBlob* cb) {
557 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
558 if (nm != NULL) {
559 // Verify that the nemthod is live
560 if (!nm->is_alive()) {
561 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " PTR_FORMAT " in its strong code roots",
562 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
563 _failures = true;
564 } else {
565 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
566 nm->oops_do(&oop_cl);
567 if (!oop_cl.has_oops_in_region()) {
568 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " PTR_FORMAT " in its strong code roots with no pointers into region",
569 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
570 _failures = true;
571 } else if (oop_cl.failures()) {
572 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has other failures for nmethod " PTR_FORMAT,
573 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
574 _failures = true;
575 }
576 }
577 }
578 }
579
580 bool failures() { return _failures; }
581 };
582
583 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
584 if (!G1VerifyHeapRegionCodeRoots) {
585 // We're not verifying code roots.
586 return;
587 }
588 if (vo == VerifyOption_G1UseMarkWord) {
589 // Marking verification during a full GC is performed after class
590 // unloading, code cache unloading, etc so the strong code roots
591 // attached to each heap region are in an inconsistent state. They won't
592 // be consistent until the strong code roots are rebuilt after the
593 // actual GC. Skip verifying the strong code roots in this particular
594 // time.
595 assert(VerifyDuringGC, "only way to get here");
596 return;
597 }
598
599 HeapRegionRemSet* hrrs = rem_set();
600 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
601
602 // if this region is empty then there should be no entries
603 // on its strong code root list
604 if (is_empty()) {
605 if (strong_code_roots_length > 0) {
606 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] is empty but has " SIZE_FORMAT " code root entries",
607 p2i(bottom()), p2i(end()), strong_code_roots_length);
608 *failures = true;
609 }
610 return;
611 }
612
613 if (is_continues_humongous()) {
614 if (strong_code_roots_length > 0) {
615 log_error(gc, verify)("region " HR_FORMAT " is a continuation of a humongous region but has " SIZE_FORMAT " code root entries",
616 HR_FORMAT_PARAMS(this), strong_code_roots_length);
617 *failures = true;
618 }
619 return;
620 }
621
622 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
623 strong_code_roots_do(&cb_cl);
624
625 if (cb_cl.failures()) {
626 *failures = true;
627 }
628 }
629
630 void HeapRegion::print() const { print_on(tty); }
631 void HeapRegion::print_on(outputStream* st) const {
632 st->print("|%4u", this->_hrm_index);
633 st->print("|" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT,
634 p2i(bottom()), p2i(top()), p2i(end()));
635 st->print("|%3d%%", (int) ((double) used() * 100 / capacity()));
636 st->print("|%2s", get_short_type_str());
637 if (in_collection_set()) {
638 st->print("|CS");
639 } else {
640 st->print("| ");
641 }
642 st->print("|TS%3u", _gc_time_stamp);
643 st->print("|AC%3u", allocation_context());
644 st->print_cr("|TAMS " PTR_FORMAT ", " PTR_FORMAT "|",
645 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start()));
646 }
647
648 class G1VerificationClosure : public OopClosure {
649 protected:
650 G1CollectedHeap* _g1h;
651 CardTableModRefBS* _bs;
652 oop _containing_obj;
653 bool _failures;
654 int _n_failures;
655 VerifyOption _vo;
656 public:
657 // _vo == UsePrevMarking -> use "prev" marking information,
658 // _vo == UseNextMarking -> use "next" marking information,
659 // _vo == UseMarkWord -> use mark word from object header.
660 G1VerificationClosure(G1CollectedHeap* g1h, VerifyOption vo) :
661 _g1h(g1h), _bs(barrier_set_cast<CardTableModRefBS>(g1h->barrier_set())),
662 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo) {
663 }
664
665 void set_containing_obj(oop obj) {
666 _containing_obj = obj;
667 }
668
669 bool failures() { return _failures; }
670 int n_failures() { return _n_failures; }
671
672 void print_object(outputStream* out, oop obj) {
673 #ifdef PRODUCT
674 Klass* k = obj->klass();
675 const char* class_name = k->external_name();
676 out->print_cr("class name %s", class_name);
677 #else // PRODUCT
678 obj->print_on(out);
679 #endif // PRODUCT
680 }
681 };
682
683 class VerifyLiveClosure : public G1VerificationClosure {
684 public:
685 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
686 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
687 virtual void do_oop(oop* p) { do_oop_work(p); }
688
689 template <class T>
690 void do_oop_work(T* p) {
691 assert(_containing_obj != NULL, "Precondition");
692 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
693 "Precondition");
694 verify_liveness(p);
695 }
696
697 template <class T>
698 void verify_liveness(T* p) {
699 T heap_oop = oopDesc::load_heap_oop(p);
700 Log(gc, verify) log;
701 if (!oopDesc::is_null(heap_oop)) {
702 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
703 bool failed = false;
704 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
705 MutexLockerEx x(ParGCRareEvent_lock,
706 Mutex::_no_safepoint_check_flag);
707
708 if (!_failures) {
709 log.error("----------");
710 }
711 ResourceMark rm;
712 if (!_g1h->is_in_closed_subset(obj)) {
713 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
714 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
715 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
716 print_object(log.error_stream(), _containing_obj);
717 log.error("points to obj " PTR_FORMAT " not in the heap", p2i(obj));
718 } else {
719 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
720 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
721 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
722 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
723 print_object(log.error_stream(), _containing_obj);
724 log.error("points to dead obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
725 p2i(obj), p2i(to->bottom()), p2i(to->end()));
726 print_object(log.error_stream(), obj);
727 }
728 log.error("----------");
729 _failures = true;
730 failed = true;
731 _n_failures++;
732 }
733 }
734 }
735 };
736
737 class VerifyRemSetClosure : public G1VerificationClosure {
738 public:
739 VerifyRemSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
740 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
741 virtual void do_oop(oop* p) { do_oop_work(p); }
742
743 template <class T>
744 void do_oop_work(T* p) {
745 assert(_containing_obj != NULL, "Precondition");
746 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
747 "Precondition");
748 verify_remembered_set(p);
749 }
750
751 template <class T>
752 void verify_remembered_set(T* p) {
753 T heap_oop = oopDesc::load_heap_oop(p);
754 Log(gc, verify) log;
755 if (!oopDesc::is_null(heap_oop)) {
756 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
757 bool failed = false;
758 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
759 HeapRegion* to = _g1h->heap_region_containing(obj);
760 if (from != NULL && to != NULL &&
761 from != to &&
762 !to->is_pinned()) {
763 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
764 jbyte cv_field = *_bs->byte_for_const(p);
765 const jbyte dirty = CardTableModRefBS::dirty_card_val();
766
767 bool is_bad = !(from->is_young()
768 || to->rem_set()->contains_reference(p)
769 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
770 (_containing_obj->is_objArray() ?
771 cv_field == dirty
772 : cv_obj == dirty || cv_field == dirty));
773 if (is_bad) {
774 MutexLockerEx x(ParGCRareEvent_lock,
775 Mutex::_no_safepoint_check_flag);
776
777 if (!_failures) {
778 log.error("----------");
779 }
780 log.error("Missing rem set entry:");
781 log.error("Field " PTR_FORMAT " of obj " PTR_FORMAT ", in region " HR_FORMAT,
782 p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
783 ResourceMark rm;
784 _containing_obj->print_on(log.error_stream());
785 log.error("points to obj " PTR_FORMAT " in region " HR_FORMAT, p2i(obj), HR_FORMAT_PARAMS(to));
786 if (obj->is_oop()) {
787 obj->print_on(log.error_stream());
788 }
789 log.error("Obj head CTE = %d, field CTE = %d.", cv_obj, cv_field);
790 log.error("----------");
791 _failures = true;
792 if (!failed) _n_failures++;
793 }
794 }
795 }
796 }
797 };
798
799 // This really ought to be commoned up into OffsetTableContigSpace somehow.
800 // We would need a mechanism to make that code skip dead objects.
801
802 void HeapRegion::verify(VerifyOption vo,
803 bool* failures) const {
804 G1CollectedHeap* g1 = G1CollectedHeap::heap();
805 *failures = false;
806 HeapWord* p = bottom();
807 HeapWord* prev_p = NULL;
808 VerifyLiveClosure vl_cl(g1, vo);
809 VerifyRemSetClosure vr_cl(g1, vo);
810 bool is_region_humongous = is_humongous();
811 size_t object_num = 0;
812 while (p < top()) {
813 oop obj = oop(p);
814 size_t obj_size = block_size(p);
815 object_num += 1;
816
817 if (!g1->is_obj_dead_cond(obj, this, vo)) {
818 if (obj->is_oop()) {
819 Klass* klass = obj->klass();
820 bool is_metaspace_object = Metaspace::contains(klass) ||
821 (vo == VerifyOption_G1UsePrevMarking &&
822 ClassLoaderDataGraph::unload_list_contains(klass));
823 if (!is_metaspace_object) {
824 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
825 "not metadata", p2i(klass), p2i(obj));
826 *failures = true;
827 return;
828 } else if (!klass->is_klass()) {
829 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
830 "not a klass", p2i(klass), p2i(obj));
831 *failures = true;
832 return;
833 } else {
834 vl_cl.set_containing_obj(obj);
835 if (!g1->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) {
836 // verify liveness and rem_set
837 vr_cl.set_containing_obj(obj);
838 G1Mux2Closure mux(&vl_cl, &vr_cl);
839 obj->oop_iterate_no_header(&mux);
840
841 if (vr_cl.failures()) {
842 *failures = true;
843 }
844 if (G1MaxVerifyFailures >= 0 &&
845 vr_cl.n_failures() >= G1MaxVerifyFailures) {
846 return;
847 }
848 } else {
849 // verify only liveness
850 obj->oop_iterate_no_header(&vl_cl);
851 }
852 if (vl_cl.failures()) {
853 *failures = true;
854 }
855 if (G1MaxVerifyFailures >= 0 &&
856 vl_cl.n_failures() >= G1MaxVerifyFailures) {
857 return;
858 }
859 }
860 } else {
861 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
862 *failures = true;
863 return;
864 }
865 }
866 prev_p = p;
867 p += obj_size;
868 }
869
870 if (!is_young() && !is_empty()) {
871 _bot_part.verify();
872 }
873
874 if (is_region_humongous) {
875 oop obj = oop(this->humongous_start_region()->bottom());
876 if ((HeapWord*)obj > bottom() || (HeapWord*)obj + obj->size() < bottom()) {
877 log_error(gc, verify)("this humongous region is not part of its' humongous object " PTR_FORMAT, p2i(obj));
878 *failures = true;
879 return;
880 }
881 }
882
883 if (!is_region_humongous && p != top()) {
884 log_error(gc, verify)("end of last object " PTR_FORMAT " "
885 "does not match top " PTR_FORMAT, p2i(p), p2i(top()));
886 *failures = true;
887 return;
888 }
889
890 HeapWord* the_end = end();
891 // Do some extra BOT consistency checking for addresses in the
892 // range [top, end). BOT look-ups in this range should yield
893 // top. No point in doing that if top == end (there's nothing there).
894 if (p < the_end) {
895 // Look up top
896 HeapWord* addr_1 = p;
897 HeapWord* b_start_1 = _bot_part.block_start_const(addr_1);
898 if (b_start_1 != p) {
899 log_error(gc, verify)("BOT look up for top: " PTR_FORMAT " "
900 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
901 p2i(addr_1), p2i(b_start_1), p2i(p));
902 *failures = true;
903 return;
904 }
905
906 // Look up top + 1
907 HeapWord* addr_2 = p + 1;
908 if (addr_2 < the_end) {
909 HeapWord* b_start_2 = _bot_part.block_start_const(addr_2);
910 if (b_start_2 != p) {
911 log_error(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " "
912 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
913 p2i(addr_2), p2i(b_start_2), p2i(p));
914 *failures = true;
915 return;
916 }
917 }
918
919 // Look up an address between top and end
920 size_t diff = pointer_delta(the_end, p) / 2;
921 HeapWord* addr_3 = p + diff;
922 if (addr_3 < the_end) {
923 HeapWord* b_start_3 = _bot_part.block_start_const(addr_3);
924 if (b_start_3 != p) {
925 log_error(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " "
926 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
927 p2i(addr_3), p2i(b_start_3), p2i(p));
928 *failures = true;
929 return;
930 }
931 }
932
933 // Look up end - 1
934 HeapWord* addr_4 = the_end - 1;
935 HeapWord* b_start_4 = _bot_part.block_start_const(addr_4);
936 if (b_start_4 != p) {
937 log_error(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " "
938 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
939 p2i(addr_4), p2i(b_start_4), p2i(p));
940 *failures = true;
941 return;
942 }
943 }
944
945 verify_strong_code_roots(vo, failures);
946 }
947
948 void HeapRegion::verify() const {
949 bool dummy = false;
950 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
951 }
952
953 void HeapRegion::verify_rem_set(VerifyOption vo, bool* failures) const {
954 G1CollectedHeap* g1 = G1CollectedHeap::heap();
955 *failures = false;
956 HeapWord* p = bottom();
957 HeapWord* prev_p = NULL;
958 VerifyRemSetClosure vr_cl(g1, vo);
959 while (p < top()) {
960 oop obj = oop(p);
961 size_t obj_size = block_size(p);
962
963 if (!g1->is_obj_dead_cond(obj, this, vo)) {
964 if (obj->is_oop()) {
965 vr_cl.set_containing_obj(obj);
966 obj->oop_iterate_no_header(&vr_cl);
967
968 if (vr_cl.failures()) {
969 *failures = true;
970 }
971 if (G1MaxVerifyFailures >= 0 &&
972 vr_cl.n_failures() >= G1MaxVerifyFailures) {
973 return;
974 }
975 } else {
976 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
977 *failures = true;
978 return;
979 }
980 }
981
982 prev_p = p;
983 p += obj_size;
984 }
985 }
986
987 void HeapRegion::verify_rem_set() const {
988 bool failures = false;
989 verify_rem_set(VerifyOption_G1UsePrevMarking, &failures);
990 guarantee(!failures, "HeapRegion RemSet verification failed");
991 }
992
993 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
994 scan_and_forward(this, cp);
995 }
996
997 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
998 // away eventually.
999
1000 void G1ContiguousSpace::clear(bool mangle_space) {
1001 set_top(bottom());
1002 _scan_top = bottom();
1003 CompactibleSpace::clear(mangle_space);
1004 reset_bot();
1005 }
1006
1007 #ifndef PRODUCT
1008 void G1ContiguousSpace::mangle_unused_area() {
1009 mangle_unused_area_complete();
1010 }
1011
1012 void G1ContiguousSpace::mangle_unused_area_complete() {
1013 SpaceMangler::mangle_region(MemRegion(top(), end()));
1014 }
1015 #endif
1016
1017 void G1ContiguousSpace::print() const {
1018 print_short();
1019 tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
1020 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
1021 p2i(bottom()), p2i(top()), p2i(_bot_part.threshold()), p2i(end()));
1022 }
1023
1024 HeapWord* G1ContiguousSpace::initialize_threshold() {
1025 return _bot_part.initialize_threshold();
1026 }
1027
1028 HeapWord* G1ContiguousSpace::cross_threshold(HeapWord* start,
1029 HeapWord* end) {
1030 _bot_part.alloc_block(start, end);
1031 return _bot_part.threshold();
1032 }
1033
1034 HeapWord* G1ContiguousSpace::scan_top() const {
1035 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1036 HeapWord* local_top = top();
1037 OrderAccess::loadload();
1038 const unsigned local_time_stamp = _gc_time_stamp;
1039 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
1040 if (local_time_stamp < g1h->get_gc_time_stamp()) {
1041 return local_top;
1042 } else {
1043 return _scan_top;
1044 }
1045 }
1046
1047 void G1ContiguousSpace::record_timestamp() {
1048 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1049 uint curr_gc_time_stamp = g1h->get_gc_time_stamp();
1050
1051 if (_gc_time_stamp < curr_gc_time_stamp) {
1052 // Setting the time stamp here tells concurrent readers to look at
1053 // scan_top to know the maximum allowed address to look at.
1054
1055 // scan_top should be bottom for all regions except for the
1056 // retained old alloc region which should have scan_top == top
1057 HeapWord* st = _scan_top;
1058 guarantee(st == _bottom || st == _top, "invariant");
1059
1060 _gc_time_stamp = curr_gc_time_stamp;
1061 }
1062 }
1063
1064 void G1ContiguousSpace::record_retained_region() {
1065 // scan_top is the maximum address where it's safe for the next gc to
1066 // scan this region.
1067 _scan_top = top();
1068 }
1069
1070 void G1ContiguousSpace::safe_object_iterate(ObjectClosure* blk) {
1071 object_iterate(blk);
1072 }
1073
1074 void G1ContiguousSpace::object_iterate(ObjectClosure* blk) {
1075 HeapWord* p = bottom();
1076 while (p < top()) {
1077 if (block_is_obj(p)) {
1078 blk->do_object(oop(p));
1079 }
1080 p += block_size(p);
1081 }
1082 }
1083
1084 G1ContiguousSpace::G1ContiguousSpace(G1BlockOffsetTable* bot) :
1085 _bot_part(bot, this),
1086 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
1087 _gc_time_stamp(0)
1088 {
1089 }
1090
1091 void G1ContiguousSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
1092 CompactibleSpace::initialize(mr, clear_space, mangle_space);
1093 _top = bottom();
1094 _scan_top = bottom();
1095 set_saved_mark_word(NULL);
1096 reset_bot();
1097 }
1098