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 par, 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 (!par) {
183 // If this is parallel, this will be done later.
184 HeapRegionRemSet* hrrs = rem_set();
185 if (locked) {
186 hrrs->clear_locked();
187 } else {
188 hrrs->clear();
189 }
190 }
191 zero_marked_bytes();
192
193 init_top_at_mark_start();
194 _gc_time_stamp = G1CollectedHeap::heap()->get_gc_time_stamp();
195 if (clear_space) clear(SpaceDecorator::Mangle);
196 }
197
198 void HeapRegion::par_clear() {
199 assert(used() == 0, "the region should have been already cleared");
200 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
201 HeapRegionRemSet* hrrs = rem_set();
202 hrrs->clear();
203 CardTableModRefBS* ct_bs =
204 barrier_set_cast<CardTableModRefBS>(G1CollectedHeap::heap()->barrier_set());
205 ct_bs->clear(MemRegion(bottom(), end()));
206 }
207
208 void HeapRegion::calc_gc_efficiency() {
209 // GC efficiency is the ratio of how much space would be
210 // reclaimed over how long we predict it would take to reclaim it.
211 G1CollectedHeap* g1h = G1CollectedHeap::heap();
212 G1Policy* g1p = g1h->g1_policy();
213
214 // Retrieve a prediction of the elapsed time for this region for
215 // a mixed gc because the region will only be evacuated during a
216 // mixed gc.
217 double region_elapsed_time_ms =
218 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
219 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
220 }
221
222 void HeapRegion::set_free() {
223 report_region_type_change(G1HeapRegionTraceType::Free);
224 _type.set_free();
225 }
226
227 void HeapRegion::set_eden() {
228 report_region_type_change(G1HeapRegionTraceType::Eden);
229 _type.set_eden();
230 }
231
232 void HeapRegion::set_eden_pre_gc() {
233 report_region_type_change(G1HeapRegionTraceType::Eden);
234 _type.set_eden_pre_gc();
235 }
236
237 void HeapRegion::set_survivor() {
238 report_region_type_change(G1HeapRegionTraceType::Survivor);
239 _type.set_survivor();
240 }
241
242 void HeapRegion::set_old() {
243 report_region_type_change(G1HeapRegionTraceType::Old);
244 _type.set_old();
245 }
246
247 void HeapRegion::set_archive() {
248 report_region_type_change(G1HeapRegionTraceType::Archive);
249 _type.set_archive();
250 }
251
252 void HeapRegion::set_starts_humongous(HeapWord* obj_top, size_t fill_size) {
253 assert(!is_humongous(), "sanity / pre-condition");
254 assert(top() == bottom(), "should be empty");
255
256 report_region_type_change(G1HeapRegionTraceType::StartsHumongous);
257 _type.set_starts_humongous();
258 _humongous_start_region = this;
259
260 _bot_part.set_for_starts_humongous(obj_top, fill_size);
261 }
262
263 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) {
264 assert(!is_humongous(), "sanity / pre-condition");
265 assert(top() == bottom(), "should be empty");
266 assert(first_hr->is_starts_humongous(), "pre-condition");
267
268 report_region_type_change(G1HeapRegionTraceType::ContinuesHumongous);
269 _type.set_continues_humongous();
270 _humongous_start_region = first_hr;
271 }
272
273 void HeapRegion::clear_humongous() {
274 assert(is_humongous(), "pre-condition");
275
276 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
277 _humongous_start_region = NULL;
278 }
279
280 HeapRegion::HeapRegion(uint hrm_index,
281 G1BlockOffsetTable* bot,
282 MemRegion mr) :
283 G1ContiguousSpace(bot),
284 _hrm_index(hrm_index),
285 _allocation_context(AllocationContext::system()),
286 _humongous_start_region(NULL),
287 _evacuation_failed(false),
288 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
289 _next(NULL), _prev(NULL),
290 #ifdef ASSERT
291 _containing_set(NULL),
292 #endif // ASSERT
293 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
294 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
295 _predicted_bytes_to_copy(0)
296 {
297 _rem_set = new HeapRegionRemSet(bot, this);
298
299 initialize(mr);
300 }
301
302 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
303 assert(_rem_set->is_empty(), "Remembered set must be empty");
304
305 G1ContiguousSpace::initialize(mr, clear_space, mangle_space);
306
307 hr_clear(false /*par*/, false /*clear_space*/);
308 set_top(bottom());
309 record_timestamp();
310 }
311
312 void HeapRegion::report_region_type_change(G1HeapRegionTraceType::Type to) {
313 HeapRegionTracer::send_region_type_change(_hrm_index,
314 get_trace_type(),
315 to,
316 (uintptr_t)bottom(),
317 used(),
318 (uint)allocation_context());
319 }
320
321 CompactibleSpace* HeapRegion::next_compaction_space() const {
322 return G1CollectedHeap::heap()->next_compaction_region(this);
323 }
324
325 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
326 bool during_conc_mark) {
327 // We always recreate the prev marking info and we'll explicitly
328 // mark all objects we find to be self-forwarded on the prev
329 // bitmap. So all objects need to be below PTAMS.
330 _prev_marked_bytes = 0;
331
332 if (during_initial_mark) {
333 // During initial-mark, we'll also explicitly mark all objects
334 // we find to be self-forwarded on the next bitmap. So all
335 // objects need to be below NTAMS.
336 _next_top_at_mark_start = top();
337 _next_marked_bytes = 0;
338 } else if (during_conc_mark) {
339 // During concurrent mark, all objects in the CSet (including
340 // the ones we find to be self-forwarded) are implicitly live.
341 // So all objects need to be above NTAMS.
342 _next_top_at_mark_start = bottom();
343 _next_marked_bytes = 0;
344 }
345 }
346
347 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
348 bool during_conc_mark,
349 size_t marked_bytes) {
350 assert(marked_bytes <= used(),
351 "marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used());
352 _prev_top_at_mark_start = top();
353 _prev_marked_bytes = marked_bytes;
354 }
355
356 HeapWord*
357 HeapRegion::object_iterate_mem_careful(MemRegion mr,
358 ObjectClosure* cl) {
359 G1CollectedHeap* g1h = G1CollectedHeap::heap();
360 // We used to use "block_start_careful" here. But we're actually happy
361 // to update the BOT while we do this...
362 HeapWord* cur = block_start(mr.start());
363 mr = mr.intersection(used_region());
364 if (mr.is_empty()) return NULL;
365 // Otherwise, find the obj that extends onto mr.start().
366
367 assert(cur <= mr.start()
368 && (oop(cur)->klass_or_null() == NULL ||
369 cur + oop(cur)->size() > mr.start()),
370 "postcondition of block_start");
371 oop obj;
372 while (cur < mr.end()) {
373 obj = oop(cur);
374 if (obj->klass_or_null() == NULL) {
375 // Ran into an unparseable point.
376 return cur;
377 } else if (!g1h->is_obj_dead(obj)) {
378 cl->do_object(obj);
379 }
380 cur += block_size(cur);
381 }
382 return NULL;
383 }
384
385 HeapWord*
386 HeapRegion::
387 oops_on_card_seq_iterate_careful(MemRegion mr,
388 FilterOutOfRegionClosure* cl,
389 bool filter_young,
390 jbyte* card_ptr) {
391 // Currently, we should only have to clean the card if filter_young
392 // is true and vice versa.
393 if (filter_young) {
394 assert(card_ptr != NULL, "pre-condition");
395 } else {
396 assert(card_ptr == NULL, "pre-condition");
397 }
398 G1CollectedHeap* g1h = G1CollectedHeap::heap();
399
400 // If we're within a stop-world GC, then we might look at a card in a
401 // GC alloc region that extends onto a GC LAB, which may not be
402 // parseable. Stop such at the "scan_top" of the region.
403 if (g1h->is_gc_active()) {
404 mr = mr.intersection(MemRegion(bottom(), scan_top()));
405 } else {
406 mr = mr.intersection(used_region());
407 }
408 if (mr.is_empty()) return NULL;
409 // Otherwise, find the obj that extends onto mr.start().
410
411 // The intersection of the incoming mr (for the card) and the
412 // allocated part of the region is non-empty. This implies that
413 // we have actually allocated into this region. The code in
414 // G1CollectedHeap.cpp that allocates a new region sets the
415 // is_young tag on the region before allocating. Thus we
416 // safely know if this region is young.
417 if (is_young() && filter_young) {
418 return NULL;
419 }
420
421 assert(!is_young(), "check value of filter_young");
422
423 // We can only clean the card here, after we make the decision that
424 // the card is not young. And we only clean the card if we have been
425 // asked to (i.e., card_ptr != NULL).
426 if (card_ptr != NULL) {
427 *card_ptr = CardTableModRefBS::clean_card_val();
428 // We must complete this write before we do any of the reads below.
429 OrderAccess::storeload();
430 }
431
432 // Cache the boundaries of the memory region in some const locals
433 HeapWord* const start = mr.start();
434 HeapWord* const end = mr.end();
435
436 // We used to use "block_start_careful" here. But we're actually happy
437 // to update the BOT while we do this...
438 HeapWord* cur = block_start(start);
439 assert(cur <= start, "Postcondition");
440
441 oop obj;
442
443 HeapWord* next = cur;
444 do {
445 cur = next;
446 obj = oop(cur);
447 if (obj->klass_or_null() == NULL) {
448 // Ran into an unparseable point.
449 return cur;
450 }
451 // Otherwise...
452 next = cur + block_size(cur);
453 } while (next <= start);
454
455 // If we finish the above loop...We have a parseable object that
456 // begins on or before the start of the memory region, and ends
457 // inside or spans the entire region.
458 assert(cur <= start, "Loop postcondition");
459 assert(obj->klass_or_null() != NULL, "Loop postcondition");
460
461 do {
462 obj = oop(cur);
463 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant");
464 if (obj->klass_or_null() == NULL) {
465 // Ran into an unparseable point.
466 return cur;
467 }
468
469 // Advance the current pointer. "obj" still points to the object to iterate.
470 cur = cur + block_size(cur);
471
472 if (!g1h->is_obj_dead(obj)) {
473 // Non-objArrays are sometimes marked imprecise at the object start. We
474 // always need to iterate over them in full.
475 // We only iterate over object arrays in full if they are completely contained
476 // in the memory region.
477 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) {
478 obj->oop_iterate(cl);
479 } else {
480 obj->oop_iterate(cl, mr);
481 }
482 }
483 } while (cur < end);
484
485 return NULL;
486 }
487
488 // Code roots support
489
490 void HeapRegion::add_strong_code_root(nmethod* nm) {
491 HeapRegionRemSet* hrrs = rem_set();
492 hrrs->add_strong_code_root(nm);
493 }
494
495 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
496 assert_locked_or_safepoint(CodeCache_lock);
497 HeapRegionRemSet* hrrs = rem_set();
498 hrrs->add_strong_code_root_locked(nm);
499 }
500
501 void HeapRegion::remove_strong_code_root(nmethod* nm) {
502 HeapRegionRemSet* hrrs = rem_set();
503 hrrs->remove_strong_code_root(nm);
504 }
505
506 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
507 HeapRegionRemSet* hrrs = rem_set();
508 hrrs->strong_code_roots_do(blk);
509 }
510
511 class VerifyStrongCodeRootOopClosure: public OopClosure {
512 const HeapRegion* _hr;
513 nmethod* _nm;
514 bool _failures;
515 bool _has_oops_in_region;
516
517 template <class T> void do_oop_work(T* p) {
518 T heap_oop = oopDesc::load_heap_oop(p);
519 if (!oopDesc::is_null(heap_oop)) {
520 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
521
522 // Note: not all the oops embedded in the nmethod are in the
523 // current region. We only look at those which are.
524 if (_hr->is_in(obj)) {
525 // Object is in the region. Check that its less than top
526 if (_hr->top() <= (HeapWord*)obj) {
527 // Object is above top
528 log_error(gc, verify)("Object " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ") is above top " PTR_FORMAT,
529 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top()));
530 _failures = true;
531 return;
532 }
533 // Nmethod has at least one oop in the current region
534 _has_oops_in_region = true;
535 }
536 }
537 }
538
539 public:
540 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
541 _hr(hr), _failures(false), _has_oops_in_region(false) {}
542
543 void do_oop(narrowOop* p) { do_oop_work(p); }
544 void do_oop(oop* p) { do_oop_work(p); }
545
546 bool failures() { return _failures; }
547 bool has_oops_in_region() { return _has_oops_in_region; }
548 };
549
550 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
551 const HeapRegion* _hr;
552 bool _failures;
553 public:
554 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
555 _hr(hr), _failures(false) {}
556
557 void do_code_blob(CodeBlob* cb) {
558 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
559 if (nm != NULL) {
560 // Verify that the nemthod is live
561 if (!nm->is_alive()) {
562 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " PTR_FORMAT " in its strong code roots",
563 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
564 _failures = true;
565 } else {
566 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
567 nm->oops_do(&oop_cl);
568 if (!oop_cl.has_oops_in_region()) {
569 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " PTR_FORMAT " in its strong code roots with no pointers into region",
570 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
571 _failures = true;
572 } else if (oop_cl.failures()) {
573 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has other failures for nmethod " PTR_FORMAT,
574 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
575 _failures = true;
576 }
577 }
578 }
579 }
580
581 bool failures() { return _failures; }
582 };
583
584 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
585 if (!G1VerifyHeapRegionCodeRoots) {
586 // We're not verifying code roots.
587 return;
588 }
589 if (vo == VerifyOption_G1UseMarkWord) {
590 // Marking verification during a full GC is performed after class
591 // unloading, code cache unloading, etc so the strong code roots
592 // attached to each heap region are in an inconsistent state. They won't
593 // be consistent until the strong code roots are rebuilt after the
594 // actual GC. Skip verifying the strong code roots in this particular
595 // time.
596 assert(VerifyDuringGC, "only way to get here");
597 return;
598 }
599
600 HeapRegionRemSet* hrrs = rem_set();
601 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
602
603 // if this region is empty then there should be no entries
604 // on its strong code root list
605 if (is_empty()) {
606 if (strong_code_roots_length > 0) {
607 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] is empty but has " SIZE_FORMAT " code root entries",
608 p2i(bottom()), p2i(end()), strong_code_roots_length);
609 *failures = true;
610 }
611 return;
612 }
613
614 if (is_continues_humongous()) {
615 if (strong_code_roots_length > 0) {
616 log_error(gc, verify)("region " HR_FORMAT " is a continuation of a humongous region but has " SIZE_FORMAT " code root entries",
617 HR_FORMAT_PARAMS(this), strong_code_roots_length);
618 *failures = true;
619 }
620 return;
621 }
622
623 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
624 strong_code_roots_do(&cb_cl);
625
626 if (cb_cl.failures()) {
627 *failures = true;
628 }
629 }
630
631 void HeapRegion::print() const { print_on(tty); }
632 void HeapRegion::print_on(outputStream* st) const {
633 st->print("|%4u", this->_hrm_index);
634 st->print("|" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT,
635 p2i(bottom()), p2i(top()), p2i(end()));
636 st->print("|%3d%%", (int) ((double) used() * 100 / capacity()));
637 st->print("|%2s", get_short_type_str());
638 if (in_collection_set()) {
639 st->print("|CS");
640 } else {
641 st->print("| ");
642 }
643 st->print("|TS%3u", _gc_time_stamp);
644 st->print("|AC%3u", allocation_context());
645 st->print_cr("|TAMS " PTR_FORMAT ", " PTR_FORMAT "|",
646 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start()));
647 }
648
649 class G1VerificationClosure : public OopClosure {
650 protected:
651 G1CollectedHeap* _g1h;
652 CardTableModRefBS* _bs;
653 oop _containing_obj;
654 bool _failures;
655 int _n_failures;
656 VerifyOption _vo;
657 public:
658 // _vo == UsePrevMarking -> use "prev" marking information,
659 // _vo == UseNextMarking -> use "next" marking information,
660 // _vo == UseMarkWord -> use mark word from object header.
661 G1VerificationClosure(G1CollectedHeap* g1h, VerifyOption vo) :
662 _g1h(g1h), _bs(barrier_set_cast<CardTableModRefBS>(g1h->barrier_set())),
663 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo) {
664 }
665
666 void set_containing_obj(oop obj) {
667 _containing_obj = obj;
668 }
669
670 bool failures() { return _failures; }
671 int n_failures() { return _n_failures; }
672
673 void print_object(outputStream* out, oop obj) {
674 #ifdef PRODUCT
675 Klass* k = obj->klass();
676 const char* class_name = k->external_name();
677 out->print_cr("class name %s", class_name);
678 #else // PRODUCT
679 obj->print_on(out);
680 #endif // PRODUCT
681 }
682 };
683
684 class VerifyLiveClosure : public G1VerificationClosure {
685 public:
686 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
687 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
688 virtual void do_oop(oop* p) { do_oop_work(p); }
689
690 template <class T>
691 void do_oop_work(T* p) {
692 assert(_containing_obj != NULL, "Precondition");
693 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
694 "Precondition");
695 verify_liveness(p);
696 }
697
698 template <class T>
699 void verify_liveness(T* p) {
700 T heap_oop = oopDesc::load_heap_oop(p);
701 Log(gc, verify) log;
702 if (!oopDesc::is_null(heap_oop)) {
703 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
704 bool failed = false;
705 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
706 MutexLockerEx x(ParGCRareEvent_lock,
707 Mutex::_no_safepoint_check_flag);
708
709 if (!_failures) {
710 log.error("----------");
711 }
712 ResourceMark rm;
713 if (!_g1h->is_in_closed_subset(obj)) {
714 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
715 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
716 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
717 print_object(log.error_stream(), _containing_obj);
718 log.error("points to obj " PTR_FORMAT " not in the heap", p2i(obj));
719 } else {
720 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
721 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
722 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
723 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
724 print_object(log.error_stream(), _containing_obj);
725 log.error("points to dead obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
726 p2i(obj), p2i(to->bottom()), p2i(to->end()));
727 print_object(log.error_stream(), obj);
728 }
729 log.error("----------");
730 _failures = true;
731 failed = true;
732 _n_failures++;
733 }
734 }
735 }
736 };
737
738 class VerifyRemSetClosure : public G1VerificationClosure {
739 public:
740 VerifyRemSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
741 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
742 virtual void do_oop(oop* p) { do_oop_work(p); }
743
744 template <class T>
745 void do_oop_work(T* p) {
746 assert(_containing_obj != NULL, "Precondition");
747 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
748 "Precondition");
749 verify_remembered_set(p);
750 }
751
752 template <class T>
753 void verify_remembered_set(T* p) {
754 T heap_oop = oopDesc::load_heap_oop(p);
755 Log(gc, verify) log;
756 if (!oopDesc::is_null(heap_oop)) {
757 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
758 bool failed = false;
759 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
760 HeapRegion* to = _g1h->heap_region_containing(obj);
761 if (from != NULL && to != NULL &&
762 from != to &&
763 !to->is_pinned()) {
764 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
765 jbyte cv_field = *_bs->byte_for_const(p);
766 const jbyte dirty = CardTableModRefBS::dirty_card_val();
767
768 bool is_bad = !(from->is_young()
769 || to->rem_set()->contains_reference(p)
770 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
771 (_containing_obj->is_objArray() ?
772 cv_field == dirty
773 : cv_obj == dirty || cv_field == dirty));
774 if (is_bad) {
775 MutexLockerEx x(ParGCRareEvent_lock,
776 Mutex::_no_safepoint_check_flag);
777
778 if (!_failures) {
779 log.error("----------");
780 }
781 log.error("Missing rem set entry:");
782 log.error("Field " PTR_FORMAT " of obj " PTR_FORMAT ", in region " HR_FORMAT,
783 p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
784 ResourceMark rm;
785 _containing_obj->print_on(log.error_stream());
786 log.error("points to obj " PTR_FORMAT " in region " HR_FORMAT, p2i(obj), HR_FORMAT_PARAMS(to));
787 if (obj->is_oop()) {
788 obj->print_on(log.error_stream());
789 }
790 log.error("Obj head CTE = %d, field CTE = %d.", cv_obj, cv_field);
791 log.error("----------");
792 _failures = true;
793 if (!failed) _n_failures++;
794 }
795 }
796 }
797 }
798 };
799
800 // This really ought to be commoned up into OffsetTableContigSpace somehow.
801 // We would need a mechanism to make that code skip dead objects.
802
803 void HeapRegion::verify(VerifyOption vo,
804 bool* failures) const {
805 G1CollectedHeap* g1 = G1CollectedHeap::heap();
806 *failures = false;
807 HeapWord* p = bottom();
808 HeapWord* prev_p = NULL;
809 VerifyLiveClosure vl_cl(g1, vo);
810 VerifyRemSetClosure vr_cl(g1, vo);
811 bool is_region_humongous = is_humongous();
812 size_t object_num = 0;
813 while (p < top()) {
814 oop obj = oop(p);
815 size_t obj_size = block_size(p);
816 object_num += 1;
817
818 if (!g1->is_obj_dead_cond(obj, this, vo)) {
819 if (obj->is_oop()) {
820 Klass* klass = obj->klass();
821 bool is_metaspace_object = Metaspace::contains(klass) ||
822 (vo == VerifyOption_G1UsePrevMarking &&
823 ClassLoaderDataGraph::unload_list_contains(klass));
824 if (!is_metaspace_object) {
825 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
826 "not metadata", p2i(klass), p2i(obj));
827 *failures = true;
828 return;
829 } else if (!klass->is_klass()) {
830 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
831 "not a klass", p2i(klass), p2i(obj));
832 *failures = true;
833 return;
834 } else {
835 vl_cl.set_containing_obj(obj);
836 if (!g1->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) {
837 // verify liveness and rem_set
838 vr_cl.set_containing_obj(obj);
839 G1Mux2Closure mux(&vl_cl, &vr_cl);
840 obj->oop_iterate_no_header(&mux);
841
842 if (vr_cl.failures()) {
843 *failures = true;
844 }
845 if (G1MaxVerifyFailures >= 0 &&
846 vr_cl.n_failures() >= G1MaxVerifyFailures) {
847 return;
848 }
849 } else {
850 // verify only liveness
851 obj->oop_iterate_no_header(&vl_cl);
852 }
853 if (vl_cl.failures()) {
854 *failures = true;
855 }
856 if (G1MaxVerifyFailures >= 0 &&
857 vl_cl.n_failures() >= G1MaxVerifyFailures) {
858 return;
859 }
860 }
861 } else {
862 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
863 *failures = true;
864 return;
865 }
866 }
867 prev_p = p;
868 p += obj_size;
869 }
870
871 if (!is_young() && !is_empty()) {
872 _bot_part.verify();
873 }
874
875 if (is_region_humongous) {
876 oop obj = oop(this->humongous_start_region()->bottom());
877 if ((HeapWord*)obj > bottom() || (HeapWord*)obj + obj->size() < bottom()) {
878 log_error(gc, verify)("this humongous region is not part of its' humongous object " PTR_FORMAT, p2i(obj));
879 *failures = true;
880 return;
881 }
882 }
883
884 if (!is_region_humongous && p != top()) {
885 log_error(gc, verify)("end of last object " PTR_FORMAT " "
886 "does not match top " PTR_FORMAT, p2i(p), p2i(top()));
887 *failures = true;
888 return;
889 }
890
891 HeapWord* the_end = end();
892 // Do some extra BOT consistency checking for addresses in the
893 // range [top, end). BOT look-ups in this range should yield
894 // top. No point in doing that if top == end (there's nothing there).
895 if (p < the_end) {
896 // Look up top
897 HeapWord* addr_1 = p;
898 HeapWord* b_start_1 = _bot_part.block_start_const(addr_1);
899 if (b_start_1 != p) {
900 log_error(gc, verify)("BOT look up for top: " PTR_FORMAT " "
901 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
902 p2i(addr_1), p2i(b_start_1), p2i(p));
903 *failures = true;
904 return;
905 }
906
907 // Look up top + 1
908 HeapWord* addr_2 = p + 1;
909 if (addr_2 < the_end) {
910 HeapWord* b_start_2 = _bot_part.block_start_const(addr_2);
911 if (b_start_2 != p) {
912 log_error(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " "
913 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
914 p2i(addr_2), p2i(b_start_2), p2i(p));
915 *failures = true;
916 return;
917 }
918 }
919
920 // Look up an address between top and end
921 size_t diff = pointer_delta(the_end, p) / 2;
922 HeapWord* addr_3 = p + diff;
923 if (addr_3 < the_end) {
924 HeapWord* b_start_3 = _bot_part.block_start_const(addr_3);
925 if (b_start_3 != p) {
926 log_error(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " "
927 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
928 p2i(addr_3), p2i(b_start_3), p2i(p));
929 *failures = true;
930 return;
931 }
932 }
933
934 // Look up end - 1
935 HeapWord* addr_4 = the_end - 1;
936 HeapWord* b_start_4 = _bot_part.block_start_const(addr_4);
937 if (b_start_4 != p) {
938 log_error(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " "
939 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
940 p2i(addr_4), p2i(b_start_4), p2i(p));
941 *failures = true;
942 return;
943 }
944 }
945
946 verify_strong_code_roots(vo, failures);
947 }
948
949 void HeapRegion::verify() const {
950 bool dummy = false;
951 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
952 }
953
954 void HeapRegion::verify_rem_set(VerifyOption vo, bool* failures) const {
955 G1CollectedHeap* g1 = G1CollectedHeap::heap();
956 *failures = false;
957 HeapWord* p = bottom();
958 HeapWord* prev_p = NULL;
959 VerifyRemSetClosure vr_cl(g1, vo);
960 while (p < top()) {
961 oop obj = oop(p);
962 size_t obj_size = block_size(p);
963
964 if (!g1->is_obj_dead_cond(obj, this, vo)) {
965 if (obj->is_oop()) {
966 vr_cl.set_containing_obj(obj);
967 obj->oop_iterate_no_header(&vr_cl);
968
969 if (vr_cl.failures()) {
970 *failures = true;
971 }
972 if (G1MaxVerifyFailures >= 0 &&
973 vr_cl.n_failures() >= G1MaxVerifyFailures) {
974 return;
975 }
976 } else {
977 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
978 *failures = true;
979 return;
980 }
981 }
982
983 prev_p = p;
984 p += obj_size;
985 }
986 }
987
988 void HeapRegion::verify_rem_set() const {
989 bool failures = false;
990 verify_rem_set(VerifyOption_G1UsePrevMarking, &failures);
991 guarantee(!failures, "HeapRegion RemSet verification failed");
992 }
993
994 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
995 scan_and_forward(this, cp);
996 }
997
998 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
999 // away eventually.
1000
1001 void G1ContiguousSpace::clear(bool mangle_space) {
1002 set_top(bottom());
1003 _scan_top = bottom();
1004 CompactibleSpace::clear(mangle_space);
1005 reset_bot();
1006 }
1007
1008 #ifndef PRODUCT
1009 void G1ContiguousSpace::mangle_unused_area() {
1010 mangle_unused_area_complete();
1011 }
1012
1013 void G1ContiguousSpace::mangle_unused_area_complete() {
1014 SpaceMangler::mangle_region(MemRegion(top(), end()));
1015 }
1016 #endif
1017
1018 void G1ContiguousSpace::print() const {
1019 print_short();
1020 tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
1021 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
1022 p2i(bottom()), p2i(top()), p2i(_bot_part.threshold()), p2i(end()));
1023 }
1024
1025 HeapWord* G1ContiguousSpace::initialize_threshold() {
1026 return _bot_part.initialize_threshold();
1027 }
1028
1029 HeapWord* G1ContiguousSpace::cross_threshold(HeapWord* start,
1030 HeapWord* end) {
1031 _bot_part.alloc_block(start, end);
1032 return _bot_part.threshold();
1033 }
1034
1035 HeapWord* G1ContiguousSpace::scan_top() const {
1036 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1037 HeapWord* local_top = top();
1038 OrderAccess::loadload();
1039 const unsigned local_time_stamp = _gc_time_stamp;
1040 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
1041 if (local_time_stamp < g1h->get_gc_time_stamp()) {
1042 return local_top;
1043 } else {
1044 return _scan_top;
1045 }
1046 }
1047
1048 void G1ContiguousSpace::record_timestamp() {
1049 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1050 uint curr_gc_time_stamp = g1h->get_gc_time_stamp();
1051
1052 if (_gc_time_stamp < curr_gc_time_stamp) {
1053 // Setting the time stamp here tells concurrent readers to look at
1054 // scan_top to know the maximum allowed address to look at.
1055
1056 // scan_top should be bottom for all regions except for the
1057 // retained old alloc region which should have scan_top == top
1058 HeapWord* st = _scan_top;
1059 guarantee(st == _bottom || st == _top, "invariant");
1060
1061 _gc_time_stamp = curr_gc_time_stamp;
1062 }
1063 }
1064
1065 void G1ContiguousSpace::record_retained_region() {
1066 // scan_top is the maximum address where it's safe for the next gc to
1067 // scan this region.
1068 _scan_top = top();
1069 }
1070
1071 void G1ContiguousSpace::safe_object_iterate(ObjectClosure* blk) {
1072 object_iterate(blk);
1073 }
1074
1075 void G1ContiguousSpace::object_iterate(ObjectClosure* blk) {
1076 HeapWord* p = bottom();
1077 while (p < top()) {
1078 if (block_is_obj(p)) {
1079 blk->do_object(oop(p));
1080 }
1081 p += block_size(p);
1082 }
1083 }
1084
1085 G1ContiguousSpace::G1ContiguousSpace(G1BlockOffsetTable* bot) :
1086 _bot_part(bot, this),
1087 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
1088 _gc_time_stamp(0)
1089 {
1090 }
1091
1092 void G1ContiguousSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
1093 CompactibleSpace::initialize(mr, clear_space, mangle_space);
1094 _top = bottom();
1095 _scan_top = bottom();
1096 set_saved_mark_word(NULL);
1097 reset_bot();
1098 }
1099