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
158 void HeapRegion::reset_after_compaction() {
159 G1ContiguousSpace::reset_after_compaction();
160 // After a compaction the mark bitmap is invalid, so we must
161 // treat all objects as being inside the unmarked area.
162 zero_marked_bytes();
163 init_top_at_mark_start();
164 }
165
166 void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
167 assert(_humongous_start_region == NULL,
168 "we should have already filtered out humongous regions");
169 assert(!in_collection_set(),
170 "Should not clear heap region %u in the collection set", hrm_index());
171
172 set_allocation_context(AllocationContext::system());
173 set_young_index_in_cset(-1);
174 uninstall_surv_rate_group();
175 set_free();
176 reset_pre_dummy_top();
177
178 if (!par) {
179 // If this is parallel, this will be done later.
180 HeapRegionRemSet* hrrs = rem_set();
181 if (locked) {
182 hrrs->clear_locked();
183 } else {
184 hrrs->clear();
185 }
186 }
187 zero_marked_bytes();
188
189 init_top_at_mark_start();
190 if (clear_space) clear(SpaceDecorator::Mangle);
191 }
192
193 void HeapRegion::par_clear() {
194 assert(used() == 0, "the region should have been already cleared");
195 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
196 HeapRegionRemSet* hrrs = rem_set();
197 hrrs->clear();
198 CardTableModRefBS* ct_bs =
199 barrier_set_cast<CardTableModRefBS>(G1CollectedHeap::heap()->barrier_set());
200 ct_bs->clear(MemRegion(bottom(), end()));
201 }
202
203 void HeapRegion::calc_gc_efficiency() {
204 // GC efficiency is the ratio of how much space would be
205 // reclaimed over how long we predict it would take to reclaim it.
206 G1CollectedHeap* g1h = G1CollectedHeap::heap();
207 G1CollectorPolicy* g1p = g1h->g1_policy();
208
209 // Retrieve a prediction of the elapsed time for this region for
210 // a mixed gc because the region will only be evacuated during a
211 // mixed gc.
212 double region_elapsed_time_ms =
213 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
214 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
215 }
216
217 void HeapRegion::set_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
268 void HeapRegion::clear_humongous() {
269 assert(is_humongous(), "pre-condition");
270
271 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
272 _humongous_start_region = NULL;
273 }
274
275 HeapRegion::HeapRegion(uint hrm_index,
276 G1BlockOffsetTable* bot,
277 MemRegion mr) :
278 G1ContiguousSpace(bot),
279 _hrm_index(hrm_index),
280 _allocation_context(AllocationContext::system()),
281 _humongous_start_region(NULL),
282 _next_in_special_set(NULL),
283 _evacuation_failed(false),
284 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
285 _next_young_region(NULL),
286 _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL),
287 #ifdef ASSERT
288 _containing_set(NULL),
289 #endif // ASSERT
290 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
291 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
292 _predicted_bytes_to_copy(0)
293 {
294 _rem_set = new HeapRegionRemSet(bot, this);
295
296 initialize(mr);
297 }
298
299 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
300 assert(_rem_set->is_empty(), "Remembered set must be empty");
301
302 G1ContiguousSpace::initialize(mr, clear_space, mangle_space);
303
304 hr_clear(false /*par*/, false /*clear_space*/);
305 set_top(bottom());
306 record_timestamp();
307 }
308
309 void HeapRegion::report_region_type_change(G1HeapRegionTraceType::Type to) {
310 HeapRegionTracer::send_region_type_change(_hrm_index,
311 get_trace_type(),
312 to,
313 (uintptr_t)bottom(),
314 used(),
315 (uint)allocation_context());
316 }
317
318 CompactibleSpace* HeapRegion::next_compaction_space() const {
319 return G1CollectedHeap::heap()->next_compaction_region(this);
320 }
321
322 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
323 bool during_conc_mark) {
324 // We always recreate the prev marking info and we'll explicitly
325 // mark all objects we find to be self-forwarded on the prev
326 // bitmap. So all objects need to be below PTAMS.
327 _prev_marked_bytes = 0;
328
329 if (during_initial_mark) {
330 // During initial-mark, we'll also explicitly mark all objects
331 // we find to be self-forwarded on the next bitmap. So all
332 // objects need to be below NTAMS.
333 _next_top_at_mark_start = top();
334 _next_marked_bytes = 0;
335 } else if (during_conc_mark) {
336 // During concurrent mark, all objects in the CSet (including
337 // the ones we find to be self-forwarded) are implicitly live.
338 // So all objects need to be above NTAMS.
339 _next_top_at_mark_start = bottom();
340 _next_marked_bytes = 0;
341 }
342 }
343
344 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
345 bool during_conc_mark,
346 size_t marked_bytes) {
347 assert(marked_bytes <= used(),
348 "marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used());
349 _prev_top_at_mark_start = top();
350 _prev_marked_bytes = marked_bytes;
351 }
352
353 HeapWord*
354 HeapRegion::object_iterate_mem_careful(MemRegion mr,
355 ObjectClosure* cl) {
356 G1CollectedHeap* g1h = G1CollectedHeap::heap();
357 // We used to use "block_start_careful" here. But we're actually happy
358 // to update the BOT while we do this...
359 HeapWord* cur = block_start(mr.start());
360 mr = mr.intersection(used_region());
361 if (mr.is_empty()) return NULL;
362 // Otherwise, find the obj that extends onto mr.start().
363
364 assert(cur <= mr.start()
365 && (oop(cur)->klass_or_null() == NULL ||
366 cur + oop(cur)->size() > mr.start()),
367 "postcondition of block_start");
368 oop obj;
369 while (cur < mr.end()) {
370 obj = oop(cur);
371 if (obj->klass_or_null() == NULL) {
372 // Ran into an unparseable point.
373 return cur;
374 } else if (!g1h->is_obj_dead(obj)) {
375 cl->do_object(obj);
376 }
377 cur += block_size(cur);
378 }
379 return NULL;
380 }
381
382 HeapWord*
383 HeapRegion::
384 oops_on_card_seq_iterate_careful(MemRegion mr,
385 FilterOutOfRegionClosure* cl,
386 bool filter_young,
387 volatile jbyte* card_ptr) {
388 // Currently, we should only have to clean the card if filter_young
389 // is true and vice versa.
390 if (filter_young) {
391 assert(card_ptr != NULL, "pre-condition");
392 } else {
393 assert(card_ptr == NULL, "pre-condition");
394 }
395 G1CollectedHeap* g1h = G1CollectedHeap::heap();
396
397 // If we're within a stop-world GC, then we might look at a card in a
398 // GC alloc region that extends onto a GC LAB, which may not be
399 // parseable. Stop such at the "scan_top" of the region.
400 if (g1h->is_gc_active()) {
401 mr = mr.intersection(MemRegion(bottom(), scan_top()));
402 } else {
403 mr = mr.intersection(used_region());
404 }
405 if (mr.is_empty()) return NULL;
406 // Otherwise, find the obj that extends onto mr.start().
407
408 // The intersection of the incoming mr (for the card) and the
409 // allocated part of the region is non-empty. This implies that
410 // we have actually allocated into this region. The code in
411 // G1CollectedHeap.cpp that allocates a new region sets the
412 // is_young tag on the region before allocating. Thus we
413 // safely know if this region is young.
414 if (is_young() && filter_young) {
415 return NULL;
416 }
417
418 assert(!is_young(), "check value of filter_young");
419
420 // We can only clean the card here, after we make the decision that
421 // the card is not young. And we only clean the card if we have been
422 // asked to (i.e., card_ptr != NULL).
423 if (card_ptr != NULL) {
424 *card_ptr = CardTableModRefBS::clean_card_val();
425 // We must complete this write before we do any of the reads below.
426 OrderAccess::storeload();
427 }
428
429 // Cache the boundaries of the memory region in some const locals
430 HeapWord* const start = mr.start();
431 HeapWord* const end = mr.end();
432
433 // We used to use "block_start_careful" here. But we're actually happy
434 // to update the BOT while we do this...
435 HeapWord* cur = block_start(start);
436 assert(cur <= start, "Postcondition");
437
438 oop obj;
439
440 HeapWord* next = cur;
441 do {
442 cur = next;
443 obj = oop(cur);
444 if (obj->klass_or_null() == NULL) {
445 // Ran into an unparseable point.
446 return cur;
447 }
448 // Otherwise...
449 next = cur + block_size(cur);
450 } while (next <= start);
451
452 // If we finish the above loop...We have a parseable object that
453 // begins on or before the start of the memory region, and ends
454 // inside or spans the entire region.
455 assert(cur <= start, "Loop postcondition");
456 assert(obj->klass_or_null() != NULL, "Loop postcondition");
457
458 do {
459 obj = oop(cur);
460 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant");
461 if (obj->klass_or_null() == NULL) {
462 // Ran into an unparseable point.
463 return cur;
464 }
465
466 // Advance the current pointer. "obj" still points to the object to iterate.
467 cur = cur + block_size(cur);
468
469 if (!g1h->is_obj_dead(obj)) {
470 // Non-objArrays are sometimes marked imprecise at the object start. We
471 // always need to iterate over them in full.
472 // We only iterate over object arrays in full if they are completely contained
473 // in the memory region.
474 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) {
475 obj->oop_iterate(cl);
476 } else {
477 obj->oop_iterate(cl, mr);
478 }
479 }
480 } while (cur < end);
481
482 return NULL;
483 }
484
485 // Code roots support
486
487 void HeapRegion::add_strong_code_root(nmethod* nm) {
488 HeapRegionRemSet* hrrs = rem_set();
489 hrrs->add_strong_code_root(nm);
490 }
491
492 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
493 assert_locked_or_safepoint(CodeCache_lock);
494 HeapRegionRemSet* hrrs = rem_set();
495 hrrs->add_strong_code_root_locked(nm);
496 }
497
498 void HeapRegion::remove_strong_code_root(nmethod* nm) {
499 HeapRegionRemSet* hrrs = rem_set();
500 hrrs->remove_strong_code_root(nm);
501 }
502
503 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
504 HeapRegionRemSet* hrrs = rem_set();
505 hrrs->strong_code_roots_do(blk);
506 }
507
508 class VerifyStrongCodeRootOopClosure: public OopClosure {
509 const HeapRegion* _hr;
510 nmethod* _nm;
511 bool _failures;
512 bool _has_oops_in_region;
513
514 template <class T> void do_oop_work(T* p) {
515 T heap_oop = oopDesc::load_heap_oop(p);
516 if (!oopDesc::is_null(heap_oop)) {
517 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
518
519 // Note: not all the oops embedded in the nmethod are in the
520 // current region. We only look at those which are.
521 if (_hr->is_in(obj)) {
522 // Object is in the region. Check that its less than top
523 if (_hr->top() <= (HeapWord*)obj) {
524 // Object is above top
525 log_error(gc, verify)("Object " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ") is above top " PTR_FORMAT,
526 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top()));
527 _failures = true;
528 return;
529 }
530 // Nmethod has at least one oop in the current region
531 _has_oops_in_region = true;
532 }
533 }
534 }
535
536 public:
537 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
538 _hr(hr), _failures(false), _has_oops_in_region(false) {}
539
540 void do_oop(narrowOop* p) { do_oop_work(p); }
541 void do_oop(oop* p) { do_oop_work(p); }
542
543 bool failures() { return _failures; }
544 bool has_oops_in_region() { return _has_oops_in_region; }
545 };
546
547 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
548 const HeapRegion* _hr;
549 bool _failures;
550 public:
551 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
552 _hr(hr), _failures(false) {}
553
554 void do_code_blob(CodeBlob* cb) {
555 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
556 if (nm != NULL) {
557 // Verify that the nemthod is live
558 if (!nm->is_alive()) {
559 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " PTR_FORMAT " in its strong code roots",
560 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
561 _failures = true;
562 } else {
563 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
564 nm->oops_do(&oop_cl);
565 if (!oop_cl.has_oops_in_region()) {
566 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " PTR_FORMAT " in its strong code roots with no pointers into region",
567 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
568 _failures = true;
569 } else if (oop_cl.failures()) {
570 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has other failures for nmethod " PTR_FORMAT,
571 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
572 _failures = true;
573 }
574 }
575 }
576 }
577
578 bool failures() { return _failures; }
579 };
580
581 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
582 if (!G1VerifyHeapRegionCodeRoots) {
583 // We're not verifying code roots.
584 return;
585 }
586 if (vo == VerifyOption_G1UseMarkWord) {
587 // Marking verification during a full GC is performed after class
588 // unloading, code cache unloading, etc so the strong code roots
589 // attached to each heap region are in an inconsistent state. They won't
590 // be consistent until the strong code roots are rebuilt after the
591 // actual GC. Skip verifying the strong code roots in this particular
592 // time.
593 assert(VerifyDuringGC, "only way to get here");
594 return;
595 }
596
597 HeapRegionRemSet* hrrs = rem_set();
598 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
599
600 // if this region is empty then there should be no entries
601 // on its strong code root list
602 if (is_empty()) {
603 if (strong_code_roots_length > 0) {
604 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] is empty but has " SIZE_FORMAT " code root entries",
605 p2i(bottom()), p2i(end()), strong_code_roots_length);
606 *failures = true;
607 }
608 return;
609 }
610
611 if (is_continues_humongous()) {
612 if (strong_code_roots_length > 0) {
613 log_error(gc, verify)("region " HR_FORMAT " is a continuation of a humongous region but has " SIZE_FORMAT " code root entries",
614 HR_FORMAT_PARAMS(this), strong_code_roots_length);
615 *failures = true;
616 }
617 return;
618 }
619
620 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
621 strong_code_roots_do(&cb_cl);
622
623 if (cb_cl.failures()) {
624 *failures = true;
625 }
626 }
627
628 void HeapRegion::print() const { print_on(tty); }
629 void HeapRegion::print_on(outputStream* st) const {
630 st->print("|%4u", this->_hrm_index);
631 st->print("|" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT,
632 p2i(bottom()), p2i(top()), p2i(end()));
633 st->print("|%3d%%", (int) ((double) used() * 100 / capacity()));
634 st->print("|%2s", get_short_type_str());
635 if (in_collection_set()) {
636 st->print("|CS");
637 } else {
638 st->print("| ");
639 }
640 st->print("|TS%3u", _gc_time_stamp);
641 st->print("|AC%3u", allocation_context());
642 st->print_cr("|TAMS " PTR_FORMAT ", " PTR_FORMAT "|",
643 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start()));
644 }
645
646 class G1VerificationClosure : public OopClosure {
647 protected:
648 G1CollectedHeap* _g1h;
649 CardTableModRefBS* _bs;
650 oop _containing_obj;
651 bool _failures;
652 int _n_failures;
653 VerifyOption _vo;
654 public:
655 // _vo == UsePrevMarking -> use "prev" marking information,
656 // _vo == UseNextMarking -> use "next" marking information,
657 // _vo == UseMarkWord -> use mark word from object header.
658 G1VerificationClosure(G1CollectedHeap* g1h, VerifyOption vo) :
659 _g1h(g1h), _bs(barrier_set_cast<CardTableModRefBS>(g1h->barrier_set())),
660 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo) {
661 }
662
663 void set_containing_obj(oop obj) {
664 _containing_obj = obj;
665 }
666
667 bool failures() { return _failures; }
668 int n_failures() { return _n_failures; }
669
670 void print_object(outputStream* out, oop obj) {
671 #ifdef PRODUCT
672 Klass* k = obj->klass();
673 const char* class_name = k->external_name();
674 out->print_cr("class name %s", class_name);
675 #else // PRODUCT
676 obj->print_on(out);
677 #endif // PRODUCT
678 }
679 };
680
681 class VerifyLiveClosure : public G1VerificationClosure {
682 public:
683 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
684 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
685 virtual void do_oop(oop* p) { do_oop_work(p); }
686
687 template <class T>
688 void do_oop_work(T* p) {
689 assert(_containing_obj != NULL, "Precondition");
690 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
691 "Precondition");
692 verify_liveness(p);
693 }
694
695 template <class T>
696 void verify_liveness(T* p) {
697 T heap_oop = oopDesc::load_heap_oop(p);
698 Log(gc, verify) log;
699 if (!oopDesc::is_null(heap_oop)) {
700 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
701 bool failed = false;
702 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
703 MutexLockerEx x(ParGCRareEvent_lock,
704 Mutex::_no_safepoint_check_flag);
705
706 if (!_failures) {
707 log.error("----------");
708 }
709 ResourceMark rm;
710 if (!_g1h->is_in_closed_subset(obj)) {
711 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
712 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
713 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
714 print_object(log.error_stream(), _containing_obj);
715 log.error("points to obj " PTR_FORMAT " not in the heap", p2i(obj));
716 } else {
717 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
718 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
719 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
720 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
721 print_object(log.error_stream(), _containing_obj);
722 log.error("points to dead obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
723 p2i(obj), p2i(to->bottom()), p2i(to->end()));
724 print_object(log.error_stream(), obj);
725 }
726 log.error("----------");
727 _failures = true;
728 failed = true;
729 _n_failures++;
730 }
731 }
732 }
733 };
734
735 class VerifyRemSetClosure : public G1VerificationClosure {
736 public:
737 VerifyRemSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
738 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
739 virtual void do_oop(oop* p) { do_oop_work(p); }
740
741 template <class T>
742 void do_oop_work(T* p) {
743 assert(_containing_obj != NULL, "Precondition");
744 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
745 "Precondition");
746 verify_remembered_set(p);
747 }
748
749 template <class T>
750 void verify_remembered_set(T* p) {
751 T heap_oop = oopDesc::load_heap_oop(p);
752 Log(gc, verify) log;
753 if (!oopDesc::is_null(heap_oop)) {
754 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
755 bool failed = false;
756 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
757 HeapRegion* to = _g1h->heap_region_containing(obj);
758 if (from != NULL && to != NULL &&
759 from != to &&
760 !to->is_pinned()) {
761 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
762 jbyte cv_field = *_bs->byte_for_const(p);
763 const jbyte dirty = CardTableModRefBS::dirty_card_val();
764
765 bool is_bad = !(from->is_young()
766 || to->rem_set()->contains_reference(p)
767 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
768 (_containing_obj->is_objArray() ?
769 cv_field == dirty
770 : cv_obj == dirty || cv_field == dirty));
771 if (is_bad) {
772 MutexLockerEx x(ParGCRareEvent_lock,
773 Mutex::_no_safepoint_check_flag);
774
775 if (!_failures) {
776 log.error("----------");
777 }
778 log.error("Missing rem set entry:");
779 log.error("Field " PTR_FORMAT " of obj " PTR_FORMAT ", in region " HR_FORMAT,
780 p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
781 ResourceMark rm;
782 _containing_obj->print_on(log.error_stream());
783 log.error("points to obj " PTR_FORMAT " in region " HR_FORMAT, p2i(obj), HR_FORMAT_PARAMS(to));
784 if (obj->is_oop()) {
785 obj->print_on(log.error_stream());
786 }
787 log.error("Obj head CTE = %d, field CTE = %d.", cv_obj, cv_field);
788 log.error("----------");
789 _failures = true;
790 if (!failed) _n_failures++;
791 }
792 }
793 }
794 }
795 };
796
797 // This really ought to be commoned up into OffsetTableContigSpace somehow.
798 // We would need a mechanism to make that code skip dead objects.
799
800 void HeapRegion::verify(VerifyOption vo,
801 bool* failures) const {
802 G1CollectedHeap* g1 = G1CollectedHeap::heap();
803 *failures = false;
804 HeapWord* p = bottom();
805 HeapWord* prev_p = NULL;
806 VerifyLiveClosure vl_cl(g1, vo);
807 VerifyRemSetClosure vr_cl(g1, vo);
808 bool is_region_humongous = is_humongous();
809 size_t object_num = 0;
810 while (p < top()) {
811 oop obj = oop(p);
812 size_t obj_size = block_size(p);
813 object_num += 1;
814
815 if (!g1->is_obj_dead_cond(obj, this, vo)) {
816 if (obj->is_oop()) {
817 Klass* klass = obj->klass();
818 bool is_metaspace_object = Metaspace::contains(klass) ||
819 (vo == VerifyOption_G1UsePrevMarking &&
820 ClassLoaderDataGraph::unload_list_contains(klass));
821 if (!is_metaspace_object) {
822 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
823 "not metadata", p2i(klass), p2i(obj));
824 *failures = true;
825 return;
826 } else if (!klass->is_klass()) {
827 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
828 "not a klass", p2i(klass), p2i(obj));
829 *failures = true;
830 return;
831 } else {
832 vl_cl.set_containing_obj(obj);
833 if (!g1->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) {
834 // verify liveness and rem_set
835 vr_cl.set_containing_obj(obj);
836 G1Mux2Closure mux(&vl_cl, &vr_cl);
837 obj->oop_iterate_no_header(&mux);
838
839 if (vr_cl.failures()) {
840 *failures = true;
841 }
842 if (G1MaxVerifyFailures >= 0 &&
843 vr_cl.n_failures() >= G1MaxVerifyFailures) {
844 return;
845 }
846 } else {
847 // verify only liveness
848 obj->oop_iterate_no_header(&vl_cl);
849 }
850 if (vl_cl.failures()) {
851 *failures = true;
852 }
853 if (G1MaxVerifyFailures >= 0 &&
854 vl_cl.n_failures() >= G1MaxVerifyFailures) {
855 return;
856 }
857 }
858 } else {
859 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
860 *failures = true;
861 return;
862 }
863 }
864 prev_p = p;
865 p += obj_size;
866 }
867
868 if (!is_young() && !is_empty()) {
869 _bot_part.verify();
870 }
871
872 if (is_region_humongous) {
873 oop obj = oop(this->humongous_start_region()->bottom());
874 if ((HeapWord*)obj > bottom() || (HeapWord*)obj + obj->size() < bottom()) {
875 log_error(gc, verify)("this humongous region is not part of its' humongous object " PTR_FORMAT, p2i(obj));
876 *failures = true;
877 return;
878 }
879 }
880
881 if (!is_region_humongous && p != top()) {
882 log_error(gc, verify)("end of last object " PTR_FORMAT " "
883 "does not match top " PTR_FORMAT, p2i(p), p2i(top()));
884 *failures = true;
885 return;
886 }
887
888 HeapWord* the_end = end();
889 // Do some extra BOT consistency checking for addresses in the
890 // range [top, end). BOT look-ups in this range should yield
891 // top. No point in doing that if top == end (there's nothing there).
892 if (p < the_end) {
893 // Look up top
894 HeapWord* addr_1 = p;
895 HeapWord* b_start_1 = _bot_part.block_start_const(addr_1);
896 if (b_start_1 != p) {
897 log_error(gc, verify)("BOT look up for top: " PTR_FORMAT " "
898 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
899 p2i(addr_1), p2i(b_start_1), p2i(p));
900 *failures = true;
901 return;
902 }
903
904 // Look up top + 1
905 HeapWord* addr_2 = p + 1;
906 if (addr_2 < the_end) {
907 HeapWord* b_start_2 = _bot_part.block_start_const(addr_2);
908 if (b_start_2 != p) {
909 log_error(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " "
910 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
911 p2i(addr_2), p2i(b_start_2), p2i(p));
912 *failures = true;
913 return;
914 }
915 }
916
917 // Look up an address between top and end
918 size_t diff = pointer_delta(the_end, p) / 2;
919 HeapWord* addr_3 = p + diff;
920 if (addr_3 < the_end) {
921 HeapWord* b_start_3 = _bot_part.block_start_const(addr_3);
922 if (b_start_3 != p) {
923 log_error(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " "
924 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
925 p2i(addr_3), p2i(b_start_3), p2i(p));
926 *failures = true;
927 return;
928 }
929 }
930
931 // Look up end - 1
932 HeapWord* addr_4 = the_end - 1;
933 HeapWord* b_start_4 = _bot_part.block_start_const(addr_4);
934 if (b_start_4 != p) {
935 log_error(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " "
936 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
937 p2i(addr_4), p2i(b_start_4), p2i(p));
938 *failures = true;
939 return;
940 }
941 }
942
943 verify_strong_code_roots(vo, failures);
944 }
945
946 void HeapRegion::verify() const {
947 bool dummy = false;
948 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
949 }
950
951 void HeapRegion::verify_rem_set(VerifyOption vo, bool* failures) const {
952 G1CollectedHeap* g1 = G1CollectedHeap::heap();
953 *failures = false;
954 HeapWord* p = bottom();
955 HeapWord* prev_p = NULL;
956 VerifyRemSetClosure vr_cl(g1, vo);
957 while (p < top()) {
958 oop obj = oop(p);
959 size_t obj_size = block_size(p);
960
961 if (!g1->is_obj_dead_cond(obj, this, vo)) {
962 if (obj->is_oop()) {
963 vr_cl.set_containing_obj(obj);
964 obj->oop_iterate_no_header(&vr_cl);
965
966 if (vr_cl.failures()) {
967 *failures = true;
968 }
969 if (G1MaxVerifyFailures >= 0 &&
970 vr_cl.n_failures() >= G1MaxVerifyFailures) {
971 return;
972 }
973 } else {
974 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
975 *failures = true;
976 return;
977 }
978 }
979
980 prev_p = p;
981 p += obj_size;
982 }
983 }
984
985 void HeapRegion::verify_rem_set() const {
986 bool failures = false;
987 verify_rem_set(VerifyOption_G1UsePrevMarking, &failures);
988 guarantee(!failures, "HeapRegion RemSet verification failed");
989 }
990
991 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
992 scan_and_forward(this, cp);
993 }
994
995 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
996 // away eventually.
997
998 void G1ContiguousSpace::clear(bool mangle_space) {
999 set_top(bottom());
1000 _scan_top = bottom();
1001 CompactibleSpace::clear(mangle_space);
1002 reset_bot();
1003 }
1004
1005 #ifndef PRODUCT
1006 void G1ContiguousSpace::mangle_unused_area() {
1007 mangle_unused_area_complete();
1008 }
1009
1010 void G1ContiguousSpace::mangle_unused_area_complete() {
1011 SpaceMangler::mangle_region(MemRegion(top(), end()));
1012 }
1013 #endif
1014
1015 void G1ContiguousSpace::print() const {
1016 print_short();
1017 tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
1018 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
1019 p2i(bottom()), p2i(top()), p2i(_bot_part.threshold()), p2i(end()));
1020 }
1021
1022 HeapWord* G1ContiguousSpace::initialize_threshold() {
1023 return _bot_part.initialize_threshold();
1024 }
1025
1026 HeapWord* G1ContiguousSpace::cross_threshold(HeapWord* start,
1027 HeapWord* end) {
1028 _bot_part.alloc_block(start, end);
1029 return _bot_part.threshold();
1030 }
1031
1032 HeapWord* G1ContiguousSpace::scan_top() const {
1033 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1034 HeapWord* local_top = top();
1035 OrderAccess::loadload();
1036 const unsigned local_time_stamp = _gc_time_stamp;
1037 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
1038 if (local_time_stamp < g1h->get_gc_time_stamp()) {
1039 return local_top;
1040 } else {
1041 return _scan_top;
1042 }
1043 }
1044
1045 void G1ContiguousSpace::record_timestamp() {
1046 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1047 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
1048
1049 if (_gc_time_stamp < curr_gc_time_stamp) {
1050 // Setting the time stamp here tells concurrent readers to look at
1051 // scan_top to know the maximum allowed address to look at.
1052
1053 // scan_top should be bottom for all regions except for the
1054 // retained old alloc region which should have scan_top == top
1055 HeapWord* st = _scan_top;
1056 guarantee(st == _bottom || st == _top, "invariant");
1057
1058 _gc_time_stamp = curr_gc_time_stamp;
1059 }
1060 }
1061
1062 void G1ContiguousSpace::record_retained_region() {
1063 // scan_top is the maximum address where it's safe for the next gc to
1064 // scan this region.
1065 _scan_top = top();
1066 }
1067
1068 void G1ContiguousSpace::safe_object_iterate(ObjectClosure* blk) {
1069 object_iterate(blk);
1070 }
1071
1072 void G1ContiguousSpace::object_iterate(ObjectClosure* blk) {
1073 HeapWord* p = bottom();
1074 while (p < top()) {
1075 if (block_is_obj(p)) {
1076 blk->do_object(oop(p));
1077 }
1078 p += block_size(p);
1079 }
1080 }
1081
1082 G1ContiguousSpace::G1ContiguousSpace(G1BlockOffsetTable* bot) :
1083 _bot_part(bot, this),
1084 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
1085 _gc_time_stamp(0)
1086 {
1087 }
1088
1089 void G1ContiguousSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
1090 CompactibleSpace::initialize(mr, clear_space, mangle_space);
1091 _top = bottom();
1092 _scan_top = bottom();
1093 set_saved_mark_word(NULL);
1094 reset_bot();
1095 }