1 /*
2 * Copyright (c) 2001, 2016, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "precompiled.hpp"
26 #include "code/nmethod.hpp"
27 #include "gc/g1/g1BlockOffsetTable.inline.hpp"
28 #include "gc/g1/g1CollectedHeap.inline.hpp"
29 #include "gc/g1/g1HeapRegionTraceType.hpp"
30 #include "gc/g1/g1OopClosures.inline.hpp"
31 #include "gc/g1/heapRegion.inline.hpp"
32 #include "gc/g1/heapRegionBounds.inline.hpp"
33 #include "gc/g1/heapRegionManager.inline.hpp"
34 #include "gc/g1/heapRegionRemSet.hpp"
35 #include "gc/g1/heapRegionTracer.hpp"
36 #include "gc/shared/genOopClosures.inline.hpp"
37 #include "gc/shared/space.inline.hpp"
38 #include "logging/log.hpp"
39 #include "memory/iterator.hpp"
40 #include "memory/resourceArea.hpp"
41 #include "oops/oop.inline.hpp"
42 #include "runtime/atomic.hpp"
43 #include "runtime/orderAccess.inline.hpp"
44
45 int HeapRegion::LogOfHRGrainBytes = 0;
46 int HeapRegion::LogOfHRGrainWords = 0;
47 size_t HeapRegion::GrainBytes = 0;
48 size_t HeapRegion::GrainWords = 0;
49 size_t HeapRegion::CardsPerRegion = 0;
50
51 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
52 HeapRegion* hr,
53 G1ParPushHeapRSClosure* cl,
54 CardTableModRefBS::PrecisionStyle precision) :
55 DirtyCardToOopClosure(hr, cl, precision, NULL),
56 _hr(hr), _rs_scan(cl), _g1(g1) { }
57
58 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
59 OopClosure* oc) :
60 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
61
62 void HeapRegionDCTOC::walk_mem_region(MemRegion mr,
63 HeapWord* bottom,
64 HeapWord* top) {
65 G1CollectedHeap* g1h = _g1;
66 size_t oop_size;
67 HeapWord* cur = bottom;
68
69 // Start filtering what we add to the remembered set. If the object is
70 // not considered dead, either because it is marked (in the mark bitmap)
71 // or it was allocated after marking finished, then we add it. Otherwise
72 // we can safely ignore the object.
73 if (!g1h->is_obj_dead(oop(cur))) {
74 oop_size = oop(cur)->oop_iterate_size(_rs_scan, mr);
75 } else {
76 oop_size = _hr->block_size(cur);
77 }
78
79 cur += oop_size;
80
81 if (cur < top) {
82 oop cur_oop = oop(cur);
83 oop_size = _hr->block_size(cur);
84 HeapWord* next_obj = cur + oop_size;
85 while (next_obj < top) {
86 // Keep filtering the remembered set.
87 if (!g1h->is_obj_dead(cur_oop)) {
88 // Bottom lies entirely below top, so we can call the
89 // non-memRegion version of oop_iterate below.
90 cur_oop->oop_iterate(_rs_scan);
91 }
92 cur = next_obj;
93 cur_oop = oop(cur);
94 oop_size = _hr->block_size(cur);
95 next_obj = cur + oop_size;
96 }
97
98 // Last object. Need to do dead-obj filtering here too.
99 if (!g1h->is_obj_dead(oop(cur))) {
100 oop(cur)->oop_iterate(_rs_scan, mr);
101 }
102 }
103 }
104
105 size_t HeapRegion::max_region_size() {
106 return HeapRegionBounds::max_size();
107 }
108
109 size_t HeapRegion::min_region_size_in_words() {
110 return HeapRegionBounds::min_size() >> LogHeapWordSize;
111 }
112
113 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
114 size_t region_size = G1HeapRegionSize;
115 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
116 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
117 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(),
118 HeapRegionBounds::min_size());
119 }
120
121 int region_size_log = log2_long((jlong) region_size);
122 // Recalculate the region size to make sure it's a power of
123 // 2. This means that region_size is the largest power of 2 that's
124 // <= what we've calculated so far.
125 region_size = ((size_t)1 << region_size_log);
126
127 // Now make sure that we don't go over or under our limits.
128 if (region_size < HeapRegionBounds::min_size()) {
129 region_size = HeapRegionBounds::min_size();
130 } else if (region_size > HeapRegionBounds::max_size()) {
131 region_size = HeapRegionBounds::max_size();
132 }
133
134 // And recalculate the log.
135 region_size_log = log2_long((jlong) region_size);
136
137 // Now, set up the globals.
138 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
139 LogOfHRGrainBytes = region_size_log;
140
141 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
142 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
143
144 guarantee(GrainBytes == 0, "we should only set it once");
145 // The cast to int is safe, given that we've bounded region_size by
146 // MIN_REGION_SIZE and MAX_REGION_SIZE.
147 GrainBytes = region_size;
148 log_info(gc, heap)("Heap region size: " SIZE_FORMAT "M", GrainBytes / M);
149
150 guarantee(GrainWords == 0, "we should only set it once");
151 GrainWords = GrainBytes >> LogHeapWordSize;
152 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
153
154 guarantee(CardsPerRegion == 0, "we should only set it once");
155 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
156
157 if (G1HeapRegionSize != GrainBytes) {
158 FLAG_SET_ERGO(size_t, G1HeapRegionSize, GrainBytes);
159 }
160 }
161
162 void HeapRegion::reset_after_compaction() {
163 G1ContiguousSpace::reset_after_compaction();
164 // After a compaction the mark bitmap is invalid, so we must
165 // treat all objects as being inside the unmarked area.
166 zero_marked_bytes();
167 init_top_at_mark_start();
168 }
169
170 void HeapRegion::hr_clear(bool keep_remset, bool clear_space, bool locked) {
171 assert(_humongous_start_region == NULL,
172 "we should have already filtered out humongous regions");
173 assert(!in_collection_set(),
174 "Should not clear heap region %u in the collection set", hrm_index());
175
176 set_allocation_context(AllocationContext::system());
177 set_young_index_in_cset(-1);
178 uninstall_surv_rate_group();
179 set_free();
180 reset_pre_dummy_top();
181
182 if (!keep_remset) {
183 if (locked) {
184 rem_set()->clear_locked();
185 } else {
186 rem_set()->clear();
187 }
188 }
189
190 zero_marked_bytes();
191
192 init_top_at_mark_start();
193 _gc_time_stamp = G1CollectedHeap::heap()->get_gc_time_stamp();
194 if (clear_space) clear(SpaceDecorator::Mangle);
195 }
196
197 void HeapRegion::par_clear() {
198 assert(used() == 0, "the region should have been already cleared");
199 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
200 HeapRegionRemSet* hrrs = rem_set();
201 hrrs->clear();
202 CardTableModRefBS* ct_bs =
203 barrier_set_cast<CardTableModRefBS>(G1CollectedHeap::heap()->barrier_set());
204 ct_bs->clear(MemRegion(bottom(), end()));
205 }
206
207 void HeapRegion::calc_gc_efficiency() {
208 // GC efficiency is the ratio of how much space would be
209 // reclaimed over how long we predict it would take to reclaim it.
210 G1CollectedHeap* g1h = G1CollectedHeap::heap();
211 G1Policy* g1p = g1h->g1_policy();
212
213 // Retrieve a prediction of the elapsed time for this region for
214 // a mixed gc because the region will only be evacuated during a
215 // mixed gc.
216 double region_elapsed_time_ms =
217 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
218 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
219 }
220
221 void HeapRegion::set_free() {
222 report_region_type_change(G1HeapRegionTraceType::Free);
223 _type.set_free();
224 }
225
226 void HeapRegion::set_eden() {
227 report_region_type_change(G1HeapRegionTraceType::Eden);
228 _type.set_eden();
229 }
230
231 void HeapRegion::set_eden_pre_gc() {
232 report_region_type_change(G1HeapRegionTraceType::Eden);
233 _type.set_eden_pre_gc();
234 }
235
236 void HeapRegion::set_survivor() {
237 report_region_type_change(G1HeapRegionTraceType::Survivor);
238 _type.set_survivor();
239 }
240
241 void HeapRegion::set_old() {
242 report_region_type_change(G1HeapRegionTraceType::Old);
243 _type.set_old();
244 }
245
246 void HeapRegion::set_archive() {
247 report_region_type_change(G1HeapRegionTraceType::Archive);
248 _type.set_archive();
249 }
250
251 void HeapRegion::set_starts_humongous(HeapWord* obj_top, size_t fill_size) {
252 assert(!is_humongous(), "sanity / pre-condition");
253 assert(top() == bottom(), "should be empty");
254
255 report_region_type_change(G1HeapRegionTraceType::StartsHumongous);
256 _type.set_starts_humongous();
257 _humongous_start_region = this;
258
259 _bot_part.set_for_starts_humongous(obj_top, fill_size);
260 }
261
262 void HeapRegion::set_continues_humongous(HeapRegion* first_hr) {
263 assert(!is_humongous(), "sanity / pre-condition");
264 assert(top() == bottom(), "should be empty");
265 assert(first_hr->is_starts_humongous(), "pre-condition");
266
267 report_region_type_change(G1HeapRegionTraceType::ContinuesHumongous);
268 _type.set_continues_humongous();
269 _humongous_start_region = first_hr;
270 }
271
272 void HeapRegion::clear_humongous() {
273 assert(is_humongous(), "pre-condition");
274
275 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
276 _humongous_start_region = NULL;
277 }
278
279 HeapRegion::HeapRegion(uint hrm_index,
280 G1BlockOffsetTable* bot,
281 MemRegion mr) :
282 G1ContiguousSpace(bot),
283 _hrm_index(hrm_index),
284 _allocation_context(AllocationContext::system()),
285 _humongous_start_region(NULL),
286 _evacuation_failed(false),
287 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
288 _next(NULL), _prev(NULL),
289 #ifdef ASSERT
290 _containing_set(NULL),
291 #endif // ASSERT
292 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
293 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
294 _predicted_bytes_to_copy(0)
295 {
296 _rem_set = new HeapRegionRemSet(bot, this);
297
298 initialize(mr);
299 }
300
301 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
302 assert(_rem_set->is_empty(), "Remembered set must be empty");
303
304 G1ContiguousSpace::initialize(mr, clear_space, mangle_space);
305
306 hr_clear(false /*par*/, false /*clear_space*/);
307 set_top(bottom());
308 record_timestamp();
309 }
310
311 void HeapRegion::report_region_type_change(G1HeapRegionTraceType::Type to) {
312 HeapRegionTracer::send_region_type_change(_hrm_index,
313 get_trace_type(),
314 to,
315 (uintptr_t)bottom(),
316 used(),
317 (uint)allocation_context());
318 }
319
320 CompactibleSpace* HeapRegion::next_compaction_space() const {
321 return G1CollectedHeap::heap()->next_compaction_region(this);
322 }
323
324 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
325 bool during_conc_mark) {
326 // We always recreate the prev marking info and we'll explicitly
327 // mark all objects we find to be self-forwarded on the prev
328 // bitmap. So all objects need to be below PTAMS.
329 _prev_marked_bytes = 0;
330
331 if (during_initial_mark) {
332 // During initial-mark, we'll also explicitly mark all objects
333 // we find to be self-forwarded on the next bitmap. So all
334 // objects need to be below NTAMS.
335 _next_top_at_mark_start = top();
336 _next_marked_bytes = 0;
337 } else if (during_conc_mark) {
338 // During concurrent mark, all objects in the CSet (including
339 // the ones we find to be self-forwarded) are implicitly live.
340 // So all objects need to be above NTAMS.
341 _next_top_at_mark_start = bottom();
342 _next_marked_bytes = 0;
343 }
344 }
345
346 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
347 bool during_conc_mark,
348 size_t marked_bytes) {
349 assert(marked_bytes <= used(),
350 "marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used());
351 _prev_top_at_mark_start = top();
352 _prev_marked_bytes = marked_bytes;
353 }
354
355 bool HeapRegion::oops_on_card_seq_iterate_careful(MemRegion mr,
356 FilterOutOfRegionClosure* cl,
357 jbyte* card_ptr) {
358 assert(card_ptr != NULL, "pre-condition");
359 G1CollectedHeap* g1h = G1CollectedHeap::heap();
360
361 // If we're within a stop-world GC, then we might look at a card in a
362 // GC alloc region that extends onto a GC LAB, which may not be
363 // parseable. Stop such at the "scan_top" of the region.
364 if (g1h->is_gc_active()) {
365 mr = mr.intersection(MemRegion(bottom(), scan_top()));
366 } else {
367 mr = mr.intersection(used_region());
368 }
369 if (mr.is_empty()) {
370 return true;
371 }
372 // Otherwise, find the obj that extends onto mr.start().
373
374 // The intersection of the incoming mr (for the card) and the
375 // allocated part of the region is non-empty. This implies that
376 // we have actually allocated into this region. The code in
377 // G1CollectedHeap.cpp that allocates a new region sets the
378 // is_young tag on the region before allocating. Thus we
379 // safely know if this region is young.
380 if (is_young()) {
381 return true;
382 }
383
384 // We can only clean the card here, after we make the decision that
385 // the card is not young.
386 *card_ptr = CardTableModRefBS::clean_card_val();
387 // We must complete this write before we do any of the reads below.
388 OrderAccess::storeload();
389
390 // Cache the boundaries of the memory region in some const locals
391 HeapWord* const start = mr.start();
392 HeapWord* const end = mr.end();
393
394 // Update BOT as needed while finding start of (potential) object.
395 HeapWord* cur = block_start(start);
396 assert(cur <= start, "Postcondition");
397
398 oop obj;
399
400 HeapWord* next = cur;
401 do {
402 cur = next;
403 obj = oop(cur);
404 if (obj->klass_or_null() == NULL) {
405 // Ran into an unparseable point.
406 assert(!g1h->is_gc_active(),
407 "Unparsable heap during GC at " PTR_FORMAT, p2i(cur));
408 return false;
409 }
410 // Otherwise...
411 next = cur + block_size(cur);
412 } while (next <= start);
413
414 // If we finish the above loop...We have a parseable object that
415 // begins on or before the start of the memory region, and ends
416 // inside or spans the entire region.
417 assert(cur <= start, "Loop postcondition");
418 assert(obj->klass_or_null() != NULL, "Loop postcondition");
419
420 do {
421 obj = oop(cur);
422 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant");
423 if (obj->klass_or_null() == NULL) {
424 // Ran into an unparseable point.
425 assert(!g1h->is_gc_active(),
426 "Unparsable heap during GC at " PTR_FORMAT, p2i(cur));
427 return false;
428 }
429
430 // Advance the current pointer. "obj" still points to the object to iterate.
431 cur = cur + block_size(cur);
432
433 if (!g1h->is_obj_dead(obj)) {
434 // Non-objArrays are sometimes marked imprecise at the object start. We
435 // always need to iterate over them in full.
436 // We only iterate over object arrays in full if they are completely contained
437 // in the memory region.
438 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) {
439 obj->oop_iterate(cl);
440 } else {
441 obj->oop_iterate(cl, mr);
442 }
443 }
444 } while (cur < end);
445
446 return true;
447 }
448
449 // Code roots support
450
451 void HeapRegion::add_strong_code_root(nmethod* nm) {
452 HeapRegionRemSet* hrrs = rem_set();
453 hrrs->add_strong_code_root(nm);
454 }
455
456 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
457 assert_locked_or_safepoint(CodeCache_lock);
458 HeapRegionRemSet* hrrs = rem_set();
459 hrrs->add_strong_code_root_locked(nm);
460 }
461
462 void HeapRegion::remove_strong_code_root(nmethod* nm) {
463 HeapRegionRemSet* hrrs = rem_set();
464 hrrs->remove_strong_code_root(nm);
465 }
466
467 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
468 HeapRegionRemSet* hrrs = rem_set();
469 hrrs->strong_code_roots_do(blk);
470 }
471
472 class VerifyStrongCodeRootOopClosure: public OopClosure {
473 const HeapRegion* _hr;
474 nmethod* _nm;
475 bool _failures;
476 bool _has_oops_in_region;
477
478 template <class T> void do_oop_work(T* p) {
479 T heap_oop = oopDesc::load_heap_oop(p);
480 if (!oopDesc::is_null(heap_oop)) {
481 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
482
483 // Note: not all the oops embedded in the nmethod are in the
484 // current region. We only look at those which are.
485 if (_hr->is_in(obj)) {
486 // Object is in the region. Check that its less than top
487 if (_hr->top() <= (HeapWord*)obj) {
488 // Object is above top
489 log_error(gc, verify)("Object " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ") is above top " PTR_FORMAT,
490 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top()));
491 _failures = true;
492 return;
493 }
494 // Nmethod has at least one oop in the current region
495 _has_oops_in_region = true;
496 }
497 }
498 }
499
500 public:
501 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
502 _hr(hr), _failures(false), _has_oops_in_region(false) {}
503
504 void do_oop(narrowOop* p) { do_oop_work(p); }
505 void do_oop(oop* p) { do_oop_work(p); }
506
507 bool failures() { return _failures; }
508 bool has_oops_in_region() { return _has_oops_in_region; }
509 };
510
511 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
512 const HeapRegion* _hr;
513 bool _failures;
514 public:
515 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
516 _hr(hr), _failures(false) {}
517
518 void do_code_blob(CodeBlob* cb) {
519 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
520 if (nm != NULL) {
521 // Verify that the nemthod is live
522 if (!nm->is_alive()) {
523 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " PTR_FORMAT " in its strong code roots",
524 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
525 _failures = true;
526 } else {
527 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
528 nm->oops_do(&oop_cl);
529 if (!oop_cl.has_oops_in_region()) {
530 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " PTR_FORMAT " in its strong code roots with no pointers into region",
531 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
532 _failures = true;
533 } else if (oop_cl.failures()) {
534 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has other failures for nmethod " PTR_FORMAT,
535 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
536 _failures = true;
537 }
538 }
539 }
540 }
541
542 bool failures() { return _failures; }
543 };
544
545 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
546 if (!G1VerifyHeapRegionCodeRoots) {
547 // We're not verifying code roots.
548 return;
549 }
550 if (vo == VerifyOption_G1UseMarkWord) {
551 // Marking verification during a full GC is performed after class
552 // unloading, code cache unloading, etc so the strong code roots
553 // attached to each heap region are in an inconsistent state. They won't
554 // be consistent until the strong code roots are rebuilt after the
555 // actual GC. Skip verifying the strong code roots in this particular
556 // time.
557 assert(VerifyDuringGC, "only way to get here");
558 return;
559 }
560
561 HeapRegionRemSet* hrrs = rem_set();
562 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
563
564 // if this region is empty then there should be no entries
565 // on its strong code root list
566 if (is_empty()) {
567 if (strong_code_roots_length > 0) {
568 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] is empty but has " SIZE_FORMAT " code root entries",
569 p2i(bottom()), p2i(end()), strong_code_roots_length);
570 *failures = true;
571 }
572 return;
573 }
574
575 if (is_continues_humongous()) {
576 if (strong_code_roots_length > 0) {
577 log_error(gc, verify)("region " HR_FORMAT " is a continuation of a humongous region but has " SIZE_FORMAT " code root entries",
578 HR_FORMAT_PARAMS(this), strong_code_roots_length);
579 *failures = true;
580 }
581 return;
582 }
583
584 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
585 strong_code_roots_do(&cb_cl);
586
587 if (cb_cl.failures()) {
588 *failures = true;
589 }
590 }
591
592 void HeapRegion::print() const { print_on(tty); }
593 void HeapRegion::print_on(outputStream* st) const {
594 st->print("|%4u", this->_hrm_index);
595 st->print("|" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT,
596 p2i(bottom()), p2i(top()), p2i(end()));
597 st->print("|%3d%%", (int) ((double) used() * 100 / capacity()));
598 st->print("|%2s", get_short_type_str());
599 if (in_collection_set()) {
600 st->print("|CS");
601 } else {
602 st->print("| ");
603 }
604 st->print("|TS%3u", _gc_time_stamp);
605 st->print("|AC%3u", allocation_context());
606 st->print_cr("|TAMS " PTR_FORMAT ", " PTR_FORMAT "|",
607 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start()));
608 }
609
610 class G1VerificationClosure : public OopClosure {
611 protected:
612 G1CollectedHeap* _g1h;
613 CardTableModRefBS* _bs;
614 oop _containing_obj;
615 bool _failures;
616 int _n_failures;
617 VerifyOption _vo;
618 public:
619 // _vo == UsePrevMarking -> use "prev" marking information,
620 // _vo == UseNextMarking -> use "next" marking information,
621 // _vo == UseMarkWord -> use mark word from object header.
622 G1VerificationClosure(G1CollectedHeap* g1h, VerifyOption vo) :
623 _g1h(g1h), _bs(barrier_set_cast<CardTableModRefBS>(g1h->barrier_set())),
624 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo) {
625 }
626
627 void set_containing_obj(oop obj) {
628 _containing_obj = obj;
629 }
630
631 bool failures() { return _failures; }
632 int n_failures() { return _n_failures; }
633
634 void print_object(outputStream* out, oop obj) {
635 #ifdef PRODUCT
636 Klass* k = obj->klass();
637 const char* class_name = k->external_name();
638 out->print_cr("class name %s", class_name);
639 #else // PRODUCT
640 obj->print_on(out);
641 #endif // PRODUCT
642 }
643 };
644
645 class VerifyLiveClosure : public G1VerificationClosure {
646 public:
647 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
648 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
649 virtual void do_oop(oop* p) { do_oop_work(p); }
650
651 template <class T>
652 void do_oop_work(T* p) {
653 assert(_containing_obj != NULL, "Precondition");
654 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
655 "Precondition");
656 verify_liveness(p);
657 }
658
659 template <class T>
660 void verify_liveness(T* p) {
661 T heap_oop = oopDesc::load_heap_oop(p);
662 Log(gc, verify) log;
663 if (!oopDesc::is_null(heap_oop)) {
664 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
665 bool failed = false;
666 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
667 MutexLockerEx x(ParGCRareEvent_lock,
668 Mutex::_no_safepoint_check_flag);
669
670 if (!_failures) {
671 log.error("----------");
672 }
673 ResourceMark rm;
674 if (!_g1h->is_in_closed_subset(obj)) {
675 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
676 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
677 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
678 print_object(log.error_stream(), _containing_obj);
679 log.error("points to obj " PTR_FORMAT " not in the heap", p2i(obj));
680 } else {
681 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
682 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
683 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
684 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
685 print_object(log.error_stream(), _containing_obj);
686 log.error("points to dead obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
687 p2i(obj), p2i(to->bottom()), p2i(to->end()));
688 print_object(log.error_stream(), obj);
689 }
690 log.error("----------");
691 _failures = true;
692 failed = true;
693 _n_failures++;
694 }
695 }
696 }
697 };
698
699 class VerifyRemSetClosure : public G1VerificationClosure {
700 public:
701 VerifyRemSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
702 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
703 virtual void do_oop(oop* p) { do_oop_work(p); }
704
705 template <class T>
706 void do_oop_work(T* p) {
707 assert(_containing_obj != NULL, "Precondition");
708 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
709 "Precondition");
710 verify_remembered_set(p);
711 }
712
713 template <class T>
714 void verify_remembered_set(T* p) {
715 T heap_oop = oopDesc::load_heap_oop(p);
716 Log(gc, verify) log;
717 if (!oopDesc::is_null(heap_oop)) {
718 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
719 bool failed = false;
720 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
721 HeapRegion* to = _g1h->heap_region_containing(obj);
722 if (from != NULL && to != NULL &&
723 from != to &&
724 !to->is_pinned()) {
725 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
726 jbyte cv_field = *_bs->byte_for_const(p);
727 const jbyte dirty = CardTableModRefBS::dirty_card_val();
728
729 bool is_bad = !(from->is_young()
730 || to->rem_set()->contains_reference(p)
731 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
732 (_containing_obj->is_objArray() ?
733 cv_field == dirty
734 : cv_obj == dirty || cv_field == dirty));
735 if (is_bad) {
736 MutexLockerEx x(ParGCRareEvent_lock,
737 Mutex::_no_safepoint_check_flag);
738
739 if (!_failures) {
740 log.error("----------");
741 }
742 log.error("Missing rem set entry:");
743 log.error("Field " PTR_FORMAT " of obj " PTR_FORMAT ", in region " HR_FORMAT,
744 p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
745 ResourceMark rm;
746 _containing_obj->print_on(log.error_stream());
747 log.error("points to obj " PTR_FORMAT " in region " HR_FORMAT, p2i(obj), HR_FORMAT_PARAMS(to));
748 if (obj->is_oop()) {
749 obj->print_on(log.error_stream());
750 }
751 log.error("Obj head CTE = %d, field CTE = %d.", cv_obj, cv_field);
752 log.error("----------");
753 _failures = true;
754 if (!failed) _n_failures++;
755 }
756 }
757 }
758 }
759 };
760
761 // This really ought to be commoned up into OffsetTableContigSpace somehow.
762 // We would need a mechanism to make that code skip dead objects.
763
764 void HeapRegion::verify(VerifyOption vo,
765 bool* failures) const {
766 G1CollectedHeap* g1 = G1CollectedHeap::heap();
767 *failures = false;
768 HeapWord* p = bottom();
769 HeapWord* prev_p = NULL;
770 VerifyLiveClosure vl_cl(g1, vo);
771 VerifyRemSetClosure vr_cl(g1, vo);
772 bool is_region_humongous = is_humongous();
773 size_t object_num = 0;
774 while (p < top()) {
775 oop obj = oop(p);
776 size_t obj_size = block_size(p);
777 object_num += 1;
778
779 if (!g1->is_obj_dead_cond(obj, this, vo)) {
780 if (obj->is_oop()) {
781 Klass* klass = obj->klass();
782 bool is_metaspace_object = Metaspace::contains(klass) ||
783 (vo == VerifyOption_G1UsePrevMarking &&
784 ClassLoaderDataGraph::unload_list_contains(klass));
785 if (!is_metaspace_object) {
786 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
787 "not metadata", p2i(klass), p2i(obj));
788 *failures = true;
789 return;
790 } else if (!klass->is_klass()) {
791 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
792 "not a klass", p2i(klass), p2i(obj));
793 *failures = true;
794 return;
795 } else {
796 vl_cl.set_containing_obj(obj);
797 if (!g1->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) {
798 // verify liveness and rem_set
799 vr_cl.set_containing_obj(obj);
800 G1Mux2Closure mux(&vl_cl, &vr_cl);
801 obj->oop_iterate_no_header(&mux);
802
803 if (vr_cl.failures()) {
804 *failures = true;
805 }
806 if (G1MaxVerifyFailures >= 0 &&
807 vr_cl.n_failures() >= G1MaxVerifyFailures) {
808 return;
809 }
810 } else {
811 // verify only liveness
812 obj->oop_iterate_no_header(&vl_cl);
813 }
814 if (vl_cl.failures()) {
815 *failures = true;
816 }
817 if (G1MaxVerifyFailures >= 0 &&
818 vl_cl.n_failures() >= G1MaxVerifyFailures) {
819 return;
820 }
821 }
822 } else {
823 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
824 *failures = true;
825 return;
826 }
827 }
828 prev_p = p;
829 p += obj_size;
830 }
831
832 if (!is_young() && !is_empty()) {
833 _bot_part.verify();
834 }
835
836 if (is_region_humongous) {
837 oop obj = oop(this->humongous_start_region()->bottom());
838 if ((HeapWord*)obj > bottom() || (HeapWord*)obj + obj->size() < bottom()) {
839 log_error(gc, verify)("this humongous region is not part of its' humongous object " PTR_FORMAT, p2i(obj));
840 *failures = true;
841 return;
842 }
843 }
844
845 if (!is_region_humongous && p != top()) {
846 log_error(gc, verify)("end of last object " PTR_FORMAT " "
847 "does not match top " PTR_FORMAT, p2i(p), p2i(top()));
848 *failures = true;
849 return;
850 }
851
852 HeapWord* the_end = end();
853 // Do some extra BOT consistency checking for addresses in the
854 // range [top, end). BOT look-ups in this range should yield
855 // top. No point in doing that if top == end (there's nothing there).
856 if (p < the_end) {
857 // Look up top
858 HeapWord* addr_1 = p;
859 HeapWord* b_start_1 = _bot_part.block_start_const(addr_1);
860 if (b_start_1 != p) {
861 log_error(gc, verify)("BOT look up for top: " PTR_FORMAT " "
862 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
863 p2i(addr_1), p2i(b_start_1), p2i(p));
864 *failures = true;
865 return;
866 }
867
868 // Look up top + 1
869 HeapWord* addr_2 = p + 1;
870 if (addr_2 < the_end) {
871 HeapWord* b_start_2 = _bot_part.block_start_const(addr_2);
872 if (b_start_2 != p) {
873 log_error(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " "
874 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
875 p2i(addr_2), p2i(b_start_2), p2i(p));
876 *failures = true;
877 return;
878 }
879 }
880
881 // Look up an address between top and end
882 size_t diff = pointer_delta(the_end, p) / 2;
883 HeapWord* addr_3 = p + diff;
884 if (addr_3 < the_end) {
885 HeapWord* b_start_3 = _bot_part.block_start_const(addr_3);
886 if (b_start_3 != p) {
887 log_error(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " "
888 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
889 p2i(addr_3), p2i(b_start_3), p2i(p));
890 *failures = true;
891 return;
892 }
893 }
894
895 // Look up end - 1
896 HeapWord* addr_4 = the_end - 1;
897 HeapWord* b_start_4 = _bot_part.block_start_const(addr_4);
898 if (b_start_4 != p) {
899 log_error(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " "
900 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
901 p2i(addr_4), p2i(b_start_4), p2i(p));
902 *failures = true;
903 return;
904 }
905 }
906
907 verify_strong_code_roots(vo, failures);
908 }
909
910 void HeapRegion::verify() const {
911 bool dummy = false;
912 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
913 }
914
915 void HeapRegion::verify_rem_set(VerifyOption vo, bool* failures) const {
916 G1CollectedHeap* g1 = G1CollectedHeap::heap();
917 *failures = false;
918 HeapWord* p = bottom();
919 HeapWord* prev_p = NULL;
920 VerifyRemSetClosure vr_cl(g1, vo);
921 while (p < top()) {
922 oop obj = oop(p);
923 size_t obj_size = block_size(p);
924
925 if (!g1->is_obj_dead_cond(obj, this, vo)) {
926 if (obj->is_oop()) {
927 vr_cl.set_containing_obj(obj);
928 obj->oop_iterate_no_header(&vr_cl);
929
930 if (vr_cl.failures()) {
931 *failures = true;
932 }
933 if (G1MaxVerifyFailures >= 0 &&
934 vr_cl.n_failures() >= G1MaxVerifyFailures) {
935 return;
936 }
937 } else {
938 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
939 *failures = true;
940 return;
941 }
942 }
943
944 prev_p = p;
945 p += obj_size;
946 }
947 }
948
949 void HeapRegion::verify_rem_set() const {
950 bool failures = false;
951 verify_rem_set(VerifyOption_G1UsePrevMarking, &failures);
952 guarantee(!failures, "HeapRegion RemSet verification failed");
953 }
954
955 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
956 scan_and_forward(this, cp);
957 }
958
959 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
960 // away eventually.
961
962 void G1ContiguousSpace::clear(bool mangle_space) {
963 set_top(bottom());
964 _scan_top = bottom();
965 CompactibleSpace::clear(mangle_space);
966 reset_bot();
967 }
968
969 #ifndef PRODUCT
970 void G1ContiguousSpace::mangle_unused_area() {
971 mangle_unused_area_complete();
972 }
973
974 void G1ContiguousSpace::mangle_unused_area_complete() {
975 SpaceMangler::mangle_region(MemRegion(top(), end()));
976 }
977 #endif
978
979 void G1ContiguousSpace::print() const {
980 print_short();
981 tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
982 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
983 p2i(bottom()), p2i(top()), p2i(_bot_part.threshold()), p2i(end()));
984 }
985
986 HeapWord* G1ContiguousSpace::initialize_threshold() {
987 return _bot_part.initialize_threshold();
988 }
989
990 HeapWord* G1ContiguousSpace::cross_threshold(HeapWord* start,
991 HeapWord* end) {
992 _bot_part.alloc_block(start, end);
993 return _bot_part.threshold();
994 }
995
996 HeapWord* G1ContiguousSpace::scan_top() const {
997 G1CollectedHeap* g1h = G1CollectedHeap::heap();
998 HeapWord* local_top = top();
999 OrderAccess::loadload();
1000 const unsigned local_time_stamp = _gc_time_stamp;
1001 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
1002 if (local_time_stamp < g1h->get_gc_time_stamp()) {
1003 return local_top;
1004 } else {
1005 return _scan_top;
1006 }
1007 }
1008
1009 void G1ContiguousSpace::record_timestamp() {
1010 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1011 uint curr_gc_time_stamp = g1h->get_gc_time_stamp();
1012
1013 if (_gc_time_stamp < curr_gc_time_stamp) {
1014 // Setting the time stamp here tells concurrent readers to look at
1015 // scan_top to know the maximum allowed address to look at.
1016
1017 // scan_top should be bottom for all regions except for the
1018 // retained old alloc region which should have scan_top == top
1019 HeapWord* st = _scan_top;
1020 guarantee(st == _bottom || st == _top, "invariant");
1021
1022 _gc_time_stamp = curr_gc_time_stamp;
1023 }
1024 }
1025
1026 void G1ContiguousSpace::record_retained_region() {
1027 // scan_top is the maximum address where it's safe for the next gc to
1028 // scan this region.
1029 _scan_top = top();
1030 }
1031
1032 void G1ContiguousSpace::safe_object_iterate(ObjectClosure* blk) {
1033 object_iterate(blk);
1034 }
1035
1036 void G1ContiguousSpace::object_iterate(ObjectClosure* blk) {
1037 HeapWord* p = bottom();
1038 while (p < top()) {
1039 if (block_is_obj(p)) {
1040 blk->do_object(oop(p));
1041 }
1042 p += block_size(p);
1043 }
1044 }
1045
1046 G1ContiguousSpace::G1ContiguousSpace(G1BlockOffsetTable* bot) :
1047 _bot_part(bot, this),
1048 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
1049 _gc_time_stamp(0)
1050 {
1051 }
1052
1053 void G1ContiguousSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
1054 CompactibleSpace::initialize(mr, clear_space, mangle_space);
1055 _top = bottom();
1056 _scan_top = bottom();
1057 set_saved_mark_word(NULL);
1058 reset_bot();
1059 }
1060