Thu, 27 Dec 2018 11:43:33 +0800
Merge
1 /*
2 * Copyright (c) 2001, 2015, 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 */
25 #include "precompiled.hpp"
26 #include "code/nmethod.hpp"
27 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
28 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
29 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
30 #include "gc_implementation/g1/heapRegion.inline.hpp"
31 #include "gc_implementation/g1/heapRegionBounds.inline.hpp"
32 #include "gc_implementation/g1/heapRegionRemSet.hpp"
33 #include "gc_implementation/g1/heapRegionManager.inline.hpp"
34 #include "gc_implementation/shared/liveRange.hpp"
35 #include "memory/genOopClosures.inline.hpp"
36 #include "memory/iterator.hpp"
37 #include "memory/space.inline.hpp"
38 #include "oops/oop.inline.hpp"
39 #include "runtime/orderAccess.inline.hpp"
41 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
43 int HeapRegion::LogOfHRGrainBytes = 0;
44 int HeapRegion::LogOfHRGrainWords = 0;
45 size_t HeapRegion::GrainBytes = 0;
46 size_t HeapRegion::GrainWords = 0;
47 size_t HeapRegion::CardsPerRegion = 0;
49 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
50 HeapRegion* hr,
51 G1ParPushHeapRSClosure* cl,
52 CardTableModRefBS::PrecisionStyle precision) :
53 DirtyCardToOopClosure(hr, cl, precision, NULL),
54 _hr(hr), _rs_scan(cl), _g1(g1) { }
56 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
57 OopClosure* oc) :
58 _r_bottom(r->bottom()), _r_end(r->end()), _oc(oc) { }
60 void HeapRegionDCTOC::walk_mem_region(MemRegion mr,
61 HeapWord* bottom,
62 HeapWord* top) {
63 G1CollectedHeap* g1h = _g1;
64 size_t oop_size;
65 HeapWord* cur = bottom;
67 // Start filtering what we add to the remembered set. If the object is
68 // not considered dead, either because it is marked (in the mark bitmap)
69 // or it was allocated after marking finished, then we add it. Otherwise
70 // we can safely ignore the object.
71 if (!g1h->is_obj_dead(oop(cur), _hr)) {
72 oop_size = oop(cur)->oop_iterate(_rs_scan, mr);
73 } else {
74 oop_size = _hr->block_size(cur);
75 }
77 cur += oop_size;
79 if (cur < top) {
80 oop cur_oop = oop(cur);
81 oop_size = _hr->block_size(cur);
82 HeapWord* next_obj = cur + oop_size;
83 while (next_obj < top) {
84 // Keep filtering the remembered set.
85 if (!g1h->is_obj_dead(cur_oop, _hr)) {
86 // Bottom lies entirely below top, so we can call the
87 // non-memRegion version of oop_iterate below.
88 cur_oop->oop_iterate(_rs_scan);
89 }
90 cur = next_obj;
91 cur_oop = oop(cur);
92 oop_size = _hr->block_size(cur);
93 next_obj = cur + oop_size;
94 }
96 // Last object. Need to do dead-obj filtering here too.
97 if (!g1h->is_obj_dead(oop(cur), _hr)) {
98 oop(cur)->oop_iterate(_rs_scan, mr);
99 }
100 }
101 }
103 size_t HeapRegion::max_region_size() {
104 return HeapRegionBounds::max_size();
105 }
107 void HeapRegion::setup_heap_region_size(size_t initial_heap_size, size_t max_heap_size) {
108 uintx region_size = G1HeapRegionSize;
109 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
110 size_t average_heap_size = (initial_heap_size + max_heap_size) / 2;
111 region_size = MAX2(average_heap_size / HeapRegionBounds::target_number(),
112 (uintx) HeapRegionBounds::min_size());
113 }
115 int region_size_log = log2_long((jlong) region_size);
116 // Recalculate the region size to make sure it's a power of
117 // 2. This means that region_size is the largest power of 2 that's
118 // <= what we've calculated so far.
119 region_size = ((uintx)1 << region_size_log);
121 // Now make sure that we don't go over or under our limits.
122 if (region_size < HeapRegionBounds::min_size()) {
123 region_size = HeapRegionBounds::min_size();
124 } else if (region_size > HeapRegionBounds::max_size()) {
125 region_size = HeapRegionBounds::max_size();
126 }
128 // And recalculate the log.
129 region_size_log = log2_long((jlong) region_size);
131 // Now, set up the globals.
132 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
133 LogOfHRGrainBytes = region_size_log;
135 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
136 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
138 guarantee(GrainBytes == 0, "we should only set it once");
139 // The cast to int is safe, given that we've bounded region_size by
140 // MIN_REGION_SIZE and MAX_REGION_SIZE.
141 GrainBytes = (size_t)region_size;
143 guarantee(GrainWords == 0, "we should only set it once");
144 GrainWords = GrainBytes >> LogHeapWordSize;
145 guarantee((size_t) 1 << LogOfHRGrainWords == GrainWords, "sanity");
147 guarantee(CardsPerRegion == 0, "we should only set it once");
148 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
149 }
151 void HeapRegion::reset_after_compaction() {
152 G1OffsetTableContigSpace::reset_after_compaction();
153 // After a compaction the mark bitmap is invalid, so we must
154 // treat all objects as being inside the unmarked area.
155 zero_marked_bytes();
156 init_top_at_mark_start();
157 }
159 void HeapRegion::hr_clear(bool par, bool clear_space, bool locked) {
160 assert(_humongous_start_region == NULL,
161 "we should have already filtered out humongous regions");
162 assert(_end == _orig_end,
163 "we should have already filtered out humongous regions");
165 _in_collection_set = false;
167 set_allocation_context(AllocationContext::system());
168 set_young_index_in_cset(-1);
169 uninstall_surv_rate_group();
170 set_free();
171 reset_pre_dummy_top();
173 if (!par) {
174 // If this is parallel, this will be done later.
175 HeapRegionRemSet* hrrs = rem_set();
176 if (locked) {
177 hrrs->clear_locked();
178 } else {
179 hrrs->clear();
180 }
181 _claimed = InitialClaimValue;
182 }
183 zero_marked_bytes();
185 _offsets.resize(HeapRegion::GrainWords);
186 init_top_at_mark_start();
187 if (clear_space) clear(SpaceDecorator::Mangle);
188 }
190 void HeapRegion::par_clear() {
191 assert(used() == 0, "the region should have been already cleared");
192 assert(capacity() == HeapRegion::GrainBytes, "should be back to normal");
193 HeapRegionRemSet* hrrs = rem_set();
194 hrrs->clear();
195 CardTableModRefBS* ct_bs =
196 (CardTableModRefBS*)G1CollectedHeap::heap()->barrier_set();
197 ct_bs->clear(MemRegion(bottom(), end()));
198 }
200 void HeapRegion::calc_gc_efficiency() {
201 // GC efficiency is the ratio of how much space would be
202 // reclaimed over how long we predict it would take to reclaim it.
203 G1CollectedHeap* g1h = G1CollectedHeap::heap();
204 G1CollectorPolicy* g1p = g1h->g1_policy();
206 // Retrieve a prediction of the elapsed time for this region for
207 // a mixed gc because the region will only be evacuated during a
208 // mixed gc.
209 double region_elapsed_time_ms =
210 g1p->predict_region_elapsed_time_ms(this, false /* for_young_gc */);
211 _gc_efficiency = (double) reclaimable_bytes() / region_elapsed_time_ms;
212 }
214 void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) {
215 assert(!isHumongous(), "sanity / pre-condition");
216 assert(end() == _orig_end,
217 "Should be normal before the humongous object allocation");
218 assert(top() == bottom(), "should be empty");
219 assert(bottom() <= new_top && new_top <= new_end, "pre-condition");
221 _type.set_starts_humongous();
222 _humongous_start_region = this;
224 set_end(new_end);
225 _offsets.set_for_starts_humongous(new_top);
226 }
228 void HeapRegion::set_continuesHumongous(HeapRegion* first_hr) {
229 assert(!isHumongous(), "sanity / pre-condition");
230 assert(end() == _orig_end,
231 "Should be normal before the humongous object allocation");
232 assert(top() == bottom(), "should be empty");
233 assert(first_hr->startsHumongous(), "pre-condition");
235 _type.set_continues_humongous();
236 _humongous_start_region = first_hr;
237 }
239 void HeapRegion::clear_humongous() {
240 assert(isHumongous(), "pre-condition");
242 if (startsHumongous()) {
243 assert(top() <= end(), "pre-condition");
244 set_end(_orig_end);
245 if (top() > end()) {
246 // at least one "continues humongous" region after it
247 set_top(end());
248 }
249 } else {
250 // continues humongous
251 assert(end() == _orig_end, "sanity");
252 }
254 assert(capacity() == HeapRegion::GrainBytes, "pre-condition");
255 _humongous_start_region = NULL;
256 }
258 bool HeapRegion::claimHeapRegion(jint claimValue) {
259 jint current = _claimed;
260 if (current != claimValue) {
261 jint res = Atomic::cmpxchg(claimValue, &_claimed, current);
262 if (res == current) {
263 return true;
264 }
265 }
266 return false;
267 }
269 HeapRegion::HeapRegion(uint hrm_index,
270 G1BlockOffsetSharedArray* sharedOffsetArray,
271 MemRegion mr) :
272 G1OffsetTableContigSpace(sharedOffsetArray, mr),
273 _hrm_index(hrm_index),
274 _allocation_context(AllocationContext::system()),
275 _humongous_start_region(NULL),
276 _in_collection_set(false),
277 _next_in_special_set(NULL), _orig_end(NULL),
278 _claimed(InitialClaimValue), _evacuation_failed(false),
279 _prev_marked_bytes(0), _next_marked_bytes(0), _gc_efficiency(0.0),
280 _next_young_region(NULL),
281 _next_dirty_cards_region(NULL), _next(NULL), _prev(NULL),
282 #ifdef ASSERT
283 _containing_set(NULL),
284 #endif // ASSERT
285 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
286 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
287 _predicted_bytes_to_copy(0)
288 {
289 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
290 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
292 initialize(mr);
293 }
295 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
296 assert(_rem_set->is_empty(), "Remembered set must be empty");
298 G1OffsetTableContigSpace::initialize(mr, clear_space, mangle_space);
300 _orig_end = mr.end();
301 hr_clear(false /*par*/, false /*clear_space*/);
302 set_top(bottom());
303 record_timestamp();
304 }
306 CompactibleSpace* HeapRegion::next_compaction_space() const {
307 return G1CollectedHeap::heap()->next_compaction_region(this);
308 }
310 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
311 bool during_conc_mark) {
312 // We always recreate the prev marking info and we'll explicitly
313 // mark all objects we find to be self-forwarded on the prev
314 // bitmap. So all objects need to be below PTAMS.
315 _prev_marked_bytes = 0;
317 if (during_initial_mark) {
318 // During initial-mark, we'll also explicitly mark all objects
319 // we find to be self-forwarded on the next bitmap. So all
320 // objects need to be below NTAMS.
321 _next_top_at_mark_start = top();
322 _next_marked_bytes = 0;
323 } else if (during_conc_mark) {
324 // During concurrent mark, all objects in the CSet (including
325 // the ones we find to be self-forwarded) are implicitly live.
326 // So all objects need to be above NTAMS.
327 _next_top_at_mark_start = bottom();
328 _next_marked_bytes = 0;
329 }
330 }
332 void HeapRegion::note_self_forwarding_removal_end(bool during_initial_mark,
333 bool during_conc_mark,
334 size_t marked_bytes) {
335 assert(0 <= marked_bytes && marked_bytes <= used(),
336 err_msg("marked: " SIZE_FORMAT " used: " SIZE_FORMAT,
337 marked_bytes, used()));
338 _prev_top_at_mark_start = top();
339 _prev_marked_bytes = marked_bytes;
340 }
342 HeapWord*
343 HeapRegion::object_iterate_mem_careful(MemRegion mr,
344 ObjectClosure* cl) {
345 G1CollectedHeap* g1h = G1CollectedHeap::heap();
346 // We used to use "block_start_careful" here. But we're actually happy
347 // to update the BOT while we do this...
348 HeapWord* cur = block_start(mr.start());
349 mr = mr.intersection(used_region());
350 if (mr.is_empty()) return NULL;
351 // Otherwise, find the obj that extends onto mr.start().
353 assert(cur <= mr.start()
354 && (oop(cur)->klass_or_null() == NULL ||
355 cur + oop(cur)->size() > mr.start()),
356 "postcondition of block_start");
357 oop obj;
358 while (cur < mr.end()) {
359 obj = oop(cur);
360 if (obj->klass_or_null() == NULL) {
361 // Ran into an unparseable point.
362 return cur;
363 } else if (!g1h->is_obj_dead(obj)) {
364 cl->do_object(obj);
365 }
366 if (cl->abort()) return cur;
367 // The check above must occur before the operation below, since an
368 // abort might invalidate the "size" operation.
369 cur += block_size(cur);
370 }
371 return NULL;
372 }
374 HeapWord*
375 HeapRegion::
376 oops_on_card_seq_iterate_careful(MemRegion mr,
377 FilterOutOfRegionClosure* cl,
378 bool filter_young,
379 jbyte* card_ptr) {
380 // Currently, we should only have to clean the card if filter_young
381 // is true and vice versa.
382 if (filter_young) {
383 assert(card_ptr != NULL, "pre-condition");
384 } else {
385 assert(card_ptr == NULL, "pre-condition");
386 }
387 G1CollectedHeap* g1h = G1CollectedHeap::heap();
389 // If we're within a stop-world GC, then we might look at a card in a
390 // GC alloc region that extends onto a GC LAB, which may not be
391 // parseable. Stop such at the "scan_top" of the region.
392 if (g1h->is_gc_active()) {
393 mr = mr.intersection(MemRegion(bottom(), scan_top()));
394 } else {
395 mr = mr.intersection(used_region());
396 }
397 if (mr.is_empty()) return NULL;
398 // Otherwise, find the obj that extends onto mr.start().
400 // The intersection of the incoming mr (for the card) and the
401 // allocated part of the region is non-empty. This implies that
402 // we have actually allocated into this region. The code in
403 // G1CollectedHeap.cpp that allocates a new region sets the
404 // is_young tag on the region before allocating. Thus we
405 // safely know if this region is young.
406 if (is_young() && filter_young) {
407 return NULL;
408 }
410 assert(!is_young(), "check value of filter_young");
412 // We can only clean the card here, after we make the decision that
413 // the card is not young. And we only clean the card if we have been
414 // asked to (i.e., card_ptr != NULL).
415 if (card_ptr != NULL) {
416 *card_ptr = CardTableModRefBS::clean_card_val();
417 // We must complete this write before we do any of the reads below.
418 OrderAccess::storeload();
419 }
421 // Cache the boundaries of the memory region in some const locals
422 HeapWord* const start = mr.start();
423 HeapWord* const end = mr.end();
425 // We used to use "block_start_careful" here. But we're actually happy
426 // to update the BOT while we do this...
427 HeapWord* cur = block_start(start);
428 assert(cur <= start, "Postcondition");
430 oop obj;
432 HeapWord* next = cur;
433 do {
434 cur = next;
435 obj = oop(cur);
436 if (obj->klass_or_null() == NULL) {
437 // Ran into an unparseable point.
438 return cur;
439 }
440 // Otherwise...
441 next = cur + block_size(cur);
442 } while (next <= start);
444 // If we finish the above loop...We have a parseable object that
445 // begins on or before the start of the memory region, and ends
446 // inside or spans the entire region.
447 assert(cur <= start, "Loop postcondition");
448 assert(obj->klass_or_null() != NULL, "Loop postcondition");
450 do {
451 obj = oop(cur);
452 assert((cur + block_size(cur)) > (HeapWord*)obj, "Loop invariant");
453 if (obj->klass_or_null() == NULL) {
454 // Ran into an unparseable point.
455 return cur;
456 }
458 // Advance the current pointer. "obj" still points to the object to iterate.
459 cur = cur + block_size(cur);
461 if (!g1h->is_obj_dead(obj)) {
462 // Non-objArrays are sometimes marked imprecise at the object start. We
463 // always need to iterate over them in full.
464 // We only iterate over object arrays in full if they are completely contained
465 // in the memory region.
466 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) {
467 obj->oop_iterate(cl);
468 } else {
469 obj->oop_iterate(cl, mr);
470 }
471 }
472 } while (cur < end);
474 return NULL;
475 }
477 // Code roots support
479 void HeapRegion::add_strong_code_root(nmethod* nm) {
480 HeapRegionRemSet* hrrs = rem_set();
481 hrrs->add_strong_code_root(nm);
482 }
484 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
485 assert_locked_or_safepoint(CodeCache_lock);
486 HeapRegionRemSet* hrrs = rem_set();
487 hrrs->add_strong_code_root_locked(nm);
488 }
490 void HeapRegion::remove_strong_code_root(nmethod* nm) {
491 HeapRegionRemSet* hrrs = rem_set();
492 hrrs->remove_strong_code_root(nm);
493 }
495 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
496 HeapRegionRemSet* hrrs = rem_set();
497 hrrs->strong_code_roots_do(blk);
498 }
500 class VerifyStrongCodeRootOopClosure: public OopClosure {
501 const HeapRegion* _hr;
502 nmethod* _nm;
503 bool _failures;
504 bool _has_oops_in_region;
506 template <class T> void do_oop_work(T* p) {
507 T heap_oop = oopDesc::load_heap_oop(p);
508 if (!oopDesc::is_null(heap_oop)) {
509 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
511 // Note: not all the oops embedded in the nmethod are in the
512 // current region. We only look at those which are.
513 if (_hr->is_in(obj)) {
514 // Object is in the region. Check that its less than top
515 if (_hr->top() <= (HeapWord*)obj) {
516 // Object is above top
517 gclog_or_tty->print_cr("Object " PTR_FORMAT " in region "
518 "[" PTR_FORMAT ", " PTR_FORMAT ") is above "
519 "top " PTR_FORMAT,
520 (void *)obj, _hr->bottom(), _hr->end(), _hr->top());
521 _failures = true;
522 return;
523 }
524 // Nmethod has at least one oop in the current region
525 _has_oops_in_region = true;
526 }
527 }
528 }
530 public:
531 VerifyStrongCodeRootOopClosure(const HeapRegion* hr, nmethod* nm):
532 _hr(hr), _failures(false), _has_oops_in_region(false) {}
534 void do_oop(narrowOop* p) { do_oop_work(p); }
535 void do_oop(oop* p) { do_oop_work(p); }
537 bool failures() { return _failures; }
538 bool has_oops_in_region() { return _has_oops_in_region; }
539 };
541 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
542 const HeapRegion* _hr;
543 bool _failures;
544 public:
545 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
546 _hr(hr), _failures(false) {}
548 void do_code_blob(CodeBlob* cb) {
549 nmethod* nm = (cb == NULL) ? NULL : cb->as_nmethod_or_null();
550 if (nm != NULL) {
551 // Verify that the nemthod is live
552 if (!nm->is_alive()) {
553 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod "
554 PTR_FORMAT " in its strong code roots",
555 _hr->bottom(), _hr->end(), nm);
556 _failures = true;
557 } else {
558 VerifyStrongCodeRootOopClosure oop_cl(_hr, nm);
559 nm->oops_do(&oop_cl);
560 if (!oop_cl.has_oops_in_region()) {
561 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod "
562 PTR_FORMAT " in its strong code roots "
563 "with no pointers into region",
564 _hr->bottom(), _hr->end(), nm);
565 _failures = true;
566 } else if (oop_cl.failures()) {
567 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] has other "
568 "failures for nmethod " PTR_FORMAT,
569 _hr->bottom(), _hr->end(), nm);
570 _failures = true;
571 }
572 }
573 }
574 }
576 bool failures() { return _failures; }
577 };
579 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
580 if (!G1VerifyHeapRegionCodeRoots) {
581 // We're not verifying code roots.
582 return;
583 }
584 if (vo == VerifyOption_G1UseMarkWord) {
585 // Marking verification during a full GC is performed after class
586 // unloading, code cache unloading, etc so the strong code roots
587 // attached to each heap region are in an inconsistent state. They won't
588 // be consistent until the strong code roots are rebuilt after the
589 // actual GC. Skip verifying the strong code roots in this particular
590 // time.
591 assert(VerifyDuringGC, "only way to get here");
592 return;
593 }
595 HeapRegionRemSet* hrrs = rem_set();
596 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
598 // if this region is empty then there should be no entries
599 // on its strong code root list
600 if (is_empty()) {
601 if (strong_code_roots_length > 0) {
602 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] is empty "
603 "but has " SIZE_FORMAT " code root entries",
604 bottom(), end(), strong_code_roots_length);
605 *failures = true;
606 }
607 return;
608 }
610 if (continuesHumongous()) {
611 if (strong_code_roots_length > 0) {
612 gclog_or_tty->print_cr("region " HR_FORMAT " is a continuation of a humongous "
613 "region but has " SIZE_FORMAT " code root entries",
614 HR_FORMAT_PARAMS(this), strong_code_roots_length);
615 *failures = true;
616 }
617 return;
618 }
620 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
621 strong_code_roots_do(&cb_cl);
623 if (cb_cl.failures()) {
624 *failures = true;
625 }
626 }
628 void HeapRegion::print() const { print_on(gclog_or_tty); }
629 void HeapRegion::print_on(outputStream* st) const {
630 st->print("AC%4u", allocation_context());
631 st->print(" %2s", get_short_type_str());
632 if (in_collection_set())
633 st->print(" CS");
634 else
635 st->print(" ");
636 st->print(" TS %5d", _gc_time_stamp);
637 st->print(" PTAMS " PTR_FORMAT " NTAMS " PTR_FORMAT,
638 prev_top_at_mark_start(), next_top_at_mark_start());
639 G1OffsetTableContigSpace::print_on(st);
640 }
642 class G1VerificationClosure : public OopClosure {
643 protected:
644 G1CollectedHeap* _g1h;
645 CardTableModRefBS* _bs;
646 oop _containing_obj;
647 bool _failures;
648 int _n_failures;
649 VerifyOption _vo;
650 public:
651 // _vo == UsePrevMarking -> use "prev" marking information,
652 // _vo == UseNextMarking -> use "next" marking information,
653 // _vo == UseMarkWord -> use mark word from object header.
654 G1VerificationClosure(G1CollectedHeap* g1h, VerifyOption vo) :
655 _g1h(g1h), _bs(NULL), _containing_obj(NULL),
656 _failures(false), _n_failures(0), _vo(vo)
657 {
658 BarrierSet* bs = _g1h->barrier_set();
659 if (bs->is_a(BarrierSet::CardTableModRef))
660 _bs = (CardTableModRefBS*)bs;
661 }
663 void set_containing_obj(oop obj) {
664 _containing_obj = obj;
665 }
667 bool failures() { return _failures; }
668 int n_failures() { return _n_failures; }
670 void print_object(outputStream* out, oop obj) {
671 #ifdef PRODUCT
672 Klass* k = obj->klass();
673 const char* class_name = InstanceKlass::cast(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 };
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); }
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 }
695 template <class T>
696 void verify_liveness(T* p) {
697 T heap_oop = oopDesc::load_heap_oop(p);
698 if (!oopDesc::is_null(heap_oop)) {
699 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
700 bool failed = false;
701 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
702 MutexLockerEx x(ParGCRareEvent_lock,
703 Mutex::_no_safepoint_check_flag);
705 if (!_failures) {
706 gclog_or_tty->cr();
707 gclog_or_tty->print_cr("----------");
708 }
709 if (!_g1h->is_in_closed_subset(obj)) {
710 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
711 gclog_or_tty->print_cr("Field " PTR_FORMAT
712 " of live obj " PTR_FORMAT " in region "
713 "[" PTR_FORMAT ", " PTR_FORMAT ")",
714 p, (void*) _containing_obj,
715 from->bottom(), from->end());
716 print_object(gclog_or_tty, _containing_obj);
717 gclog_or_tty->print_cr("points to obj " PTR_FORMAT " not in the heap",
718 (void*) obj);
719 } else {
720 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
721 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
722 gclog_or_tty->print_cr("Field " PTR_FORMAT
723 " of live obj " PTR_FORMAT " in region "
724 "[" PTR_FORMAT ", " PTR_FORMAT ")",
725 p, (void*) _containing_obj,
726 from->bottom(), from->end());
727 print_object(gclog_or_tty, _containing_obj);
728 gclog_or_tty->print_cr("points to dead obj " PTR_FORMAT " in region "
729 "[" PTR_FORMAT ", " PTR_FORMAT ")",
730 (void*) obj, to->bottom(), to->end());
731 print_object(gclog_or_tty, obj);
732 }
733 gclog_or_tty->print_cr("----------");
734 gclog_or_tty->flush();
735 _failures = true;
736 failed = true;
737 _n_failures++;
738 }
739 }
740 }
741 };
743 class VerifyRemSetClosure : public G1VerificationClosure {
744 public:
745 VerifyRemSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
746 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
747 virtual void do_oop(oop* p) { do_oop_work(p); }
749 template <class T>
750 void do_oop_work(T* p) {
751 assert(_containing_obj != NULL, "Precondition");
752 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
753 "Precondition");
754 verify_remembered_set(p);
755 }
757 template <class T>
758 void verify_remembered_set(T* p) {
759 T heap_oop = oopDesc::load_heap_oop(p);
760 if (!oopDesc::is_null(heap_oop)) {
761 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
762 bool failed = false;
763 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
764 HeapRegion* to = _g1h->heap_region_containing(obj);
765 if (from != NULL && to != NULL &&
766 from != to &&
767 !to->isHumongous()) {
768 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
769 jbyte cv_field = *_bs->byte_for_const(p);
770 const jbyte dirty = CardTableModRefBS::dirty_card_val();
772 bool is_bad = !(from->is_young()
773 || to->rem_set()->contains_reference(p)
774 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
775 (_containing_obj->is_objArray() ?
776 cv_field == dirty
777 : cv_obj == dirty || cv_field == dirty));
778 if (is_bad) {
779 MutexLockerEx x(ParGCRareEvent_lock,
780 Mutex::_no_safepoint_check_flag);
782 if (!_failures) {
783 gclog_or_tty->cr();
784 gclog_or_tty->print_cr("----------");
785 }
786 gclog_or_tty->print_cr("Missing rem set entry:");
787 gclog_or_tty->print_cr("Field " PTR_FORMAT " "
788 "of obj " PTR_FORMAT ", "
789 "in region " HR_FORMAT,
790 p, (void*) _containing_obj,
791 HR_FORMAT_PARAMS(from));
792 _containing_obj->print_on(gclog_or_tty);
793 gclog_or_tty->print_cr("points to obj " PTR_FORMAT " "
794 "in region " HR_FORMAT,
795 (void*) obj,
796 HR_FORMAT_PARAMS(to));
797 if (obj->is_oop()) {
798 obj->print_on(gclog_or_tty);
799 }
800 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
801 cv_obj, cv_field);
802 gclog_or_tty->print_cr("----------");
803 gclog_or_tty->flush();
804 _failures = true;
805 if (!failed) _n_failures++;
806 }
807 }
808 }
809 }
810 };
812 // This really ought to be commoned up into OffsetTableContigSpace somehow.
813 // We would need a mechanism to make that code skip dead objects.
815 void HeapRegion::verify(VerifyOption vo,
816 bool* failures) const {
817 G1CollectedHeap* g1 = G1CollectedHeap::heap();
818 *failures = false;
819 HeapWord* p = bottom();
820 HeapWord* prev_p = NULL;
821 VerifyLiveClosure vl_cl(g1, vo);
822 VerifyRemSetClosure vr_cl(g1, vo);
823 bool is_humongous = isHumongous();
824 bool do_bot_verify = !is_young();
825 size_t object_num = 0;
826 while (p < top()) {
827 oop obj = oop(p);
828 size_t obj_size = block_size(p);
829 object_num += 1;
831 if (is_humongous != g1->isHumongous(obj_size) &&
832 !g1->is_obj_dead(obj, this)) { // Dead objects may have bigger block_size since they span several objects.
833 gclog_or_tty->print_cr("obj " PTR_FORMAT " is of %shumongous size ("
834 SIZE_FORMAT " words) in a %shumongous region",
835 p, g1->isHumongous(obj_size) ? "" : "non-",
836 obj_size, is_humongous ? "" : "non-");
837 *failures = true;
838 return;
839 }
841 // If it returns false, verify_for_object() will output the
842 // appropriate message.
843 if (do_bot_verify &&
844 !g1->is_obj_dead(obj, this) &&
845 !_offsets.verify_for_object(p, obj_size)) {
846 *failures = true;
847 return;
848 }
850 if (!g1->is_obj_dead_cond(obj, this, vo)) {
851 if (obj->is_oop()) {
852 Klass* klass = obj->klass();
853 bool is_metaspace_object = Metaspace::contains(klass) ||
854 (vo == VerifyOption_G1UsePrevMarking &&
855 ClassLoaderDataGraph::unload_list_contains(klass));
856 if (!is_metaspace_object) {
857 gclog_or_tty->print_cr("klass " PTR_FORMAT " of object " PTR_FORMAT " "
858 "not metadata", klass, (void *)obj);
859 *failures = true;
860 return;
861 } else if (!klass->is_klass()) {
862 gclog_or_tty->print_cr("klass " PTR_FORMAT " of object " PTR_FORMAT " "
863 "not a klass", klass, (void *)obj);
864 *failures = true;
865 return;
866 } else {
867 vl_cl.set_containing_obj(obj);
868 if (!g1->full_collection() || G1VerifyRSetsDuringFullGC) {
869 // verify liveness and rem_set
870 vr_cl.set_containing_obj(obj);
871 G1Mux2Closure mux(&vl_cl, &vr_cl);
872 obj->oop_iterate_no_header(&mux);
874 if (vr_cl.failures()) {
875 *failures = true;
876 }
877 if (G1MaxVerifyFailures >= 0 &&
878 vr_cl.n_failures() >= G1MaxVerifyFailures) {
879 return;
880 }
881 } else {
882 // verify only liveness
883 obj->oop_iterate_no_header(&vl_cl);
884 }
885 if (vl_cl.failures()) {
886 *failures = true;
887 }
888 if (G1MaxVerifyFailures >= 0 &&
889 vl_cl.n_failures() >= G1MaxVerifyFailures) {
890 return;
891 }
892 }
893 } else {
894 gclog_or_tty->print_cr(PTR_FORMAT " not an oop", (void *)obj);
895 *failures = true;
896 return;
897 }
898 }
899 prev_p = p;
900 p += obj_size;
901 }
903 if (p != top()) {
904 gclog_or_tty->print_cr("end of last object " PTR_FORMAT " "
905 "does not match top " PTR_FORMAT, p, top());
906 *failures = true;
907 return;
908 }
910 HeapWord* the_end = end();
911 assert(p == top(), "it should still hold");
912 // Do some extra BOT consistency checking for addresses in the
913 // range [top, end). BOT look-ups in this range should yield
914 // top. No point in doing that if top == end (there's nothing there).
915 if (p < the_end) {
916 // Look up top
917 HeapWord* addr_1 = p;
918 HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
919 if (b_start_1 != p) {
920 gclog_or_tty->print_cr("BOT look up for top: " PTR_FORMAT " "
921 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
922 addr_1, b_start_1, p);
923 *failures = true;
924 return;
925 }
927 // Look up top + 1
928 HeapWord* addr_2 = p + 1;
929 if (addr_2 < the_end) {
930 HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
931 if (b_start_2 != p) {
932 gclog_or_tty->print_cr("BOT look up for top + 1: " PTR_FORMAT " "
933 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
934 addr_2, b_start_2, p);
935 *failures = true;
936 return;
937 }
938 }
940 // Look up an address between top and end
941 size_t diff = pointer_delta(the_end, p) / 2;
942 HeapWord* addr_3 = p + diff;
943 if (addr_3 < the_end) {
944 HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
945 if (b_start_3 != p) {
946 gclog_or_tty->print_cr("BOT look up for top + diff: " PTR_FORMAT " "
947 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
948 addr_3, b_start_3, p);
949 *failures = true;
950 return;
951 }
952 }
954 // Loook up end - 1
955 HeapWord* addr_4 = the_end - 1;
956 HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
957 if (b_start_4 != p) {
958 gclog_or_tty->print_cr("BOT look up for end - 1: " PTR_FORMAT " "
959 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
960 addr_4, b_start_4, p);
961 *failures = true;
962 return;
963 }
964 }
966 if (is_humongous && object_num > 1) {
967 gclog_or_tty->print_cr("region [" PTR_FORMAT "," PTR_FORMAT "] is humongous "
968 "but has " SIZE_FORMAT ", objects",
969 bottom(), end(), object_num);
970 *failures = true;
971 return;
972 }
974 verify_strong_code_roots(vo, failures);
975 }
977 void HeapRegion::verify() const {
978 bool dummy = false;
979 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
980 }
982 void HeapRegion::verify_rem_set(VerifyOption vo, bool* failures) const {
983 G1CollectedHeap* g1 = G1CollectedHeap::heap();
984 *failures = false;
985 HeapWord* p = bottom();
986 HeapWord* prev_p = NULL;
987 VerifyRemSetClosure vr_cl(g1, vo);
988 while (p < top()) {
989 oop obj = oop(p);
990 size_t obj_size = block_size(p);
992 if (!g1->is_obj_dead_cond(obj, this, vo)) {
993 if (obj->is_oop()) {
994 vr_cl.set_containing_obj(obj);
995 obj->oop_iterate_no_header(&vr_cl);
997 if (vr_cl.failures()) {
998 *failures = true;
999 }
1000 if (G1MaxVerifyFailures >= 0 &&
1001 vr_cl.n_failures() >= G1MaxVerifyFailures) {
1002 return;
1003 }
1004 } else {
1005 gclog_or_tty->print_cr(PTR_FORMAT " not an oop", p2i(obj));
1006 *failures = true;
1007 return;
1008 }
1009 }
1011 prev_p = p;
1012 p += obj_size;
1013 }
1014 }
1016 void HeapRegion::verify_rem_set() const {
1017 bool failures = false;
1018 verify_rem_set(VerifyOption_G1UsePrevMarking, &failures);
1019 guarantee(!failures, "HeapRegion RemSet verification failed");
1020 }
1022 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
1023 // away eventually.
1025 void G1OffsetTableContigSpace::clear(bool mangle_space) {
1026 set_top(bottom());
1027 _scan_top = bottom();
1028 CompactibleSpace::clear(mangle_space);
1029 reset_bot();
1030 }
1032 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
1033 Space::set_bottom(new_bottom);
1034 _offsets.set_bottom(new_bottom);
1035 }
1037 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
1038 Space::set_end(new_end);
1039 _offsets.resize(new_end - bottom());
1040 }
1042 void G1OffsetTableContigSpace::print() const {
1043 print_short();
1044 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
1045 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
1046 bottom(), top(), _offsets.threshold(), end());
1047 }
1049 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
1050 return _offsets.initialize_threshold();
1051 }
1053 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
1054 HeapWord* end) {
1055 _offsets.alloc_block(start, end);
1056 return _offsets.threshold();
1057 }
1059 HeapWord* G1OffsetTableContigSpace::scan_top() const {
1060 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1061 HeapWord* local_top = top();
1062 OrderAccess::loadload();
1063 const unsigned local_time_stamp = _gc_time_stamp;
1064 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
1065 if (local_time_stamp < g1h->get_gc_time_stamp()) {
1066 return local_top;
1067 } else {
1068 return _scan_top;
1069 }
1070 }
1072 void G1OffsetTableContigSpace::record_timestamp() {
1073 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1074 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
1076 if (_gc_time_stamp < curr_gc_time_stamp) {
1077 // Setting the time stamp here tells concurrent readers to look at
1078 // scan_top to know the maximum allowed address to look at.
1080 // scan_top should be bottom for all regions except for the
1081 // retained old alloc region which should have scan_top == top
1082 HeapWord* st = _scan_top;
1083 guarantee(st == _bottom || st == _top, "invariant");
1085 _gc_time_stamp = curr_gc_time_stamp;
1086 }
1087 }
1089 void G1OffsetTableContigSpace::record_retained_region() {
1090 // scan_top is the maximum address where it's safe for the next gc to
1091 // scan this region.
1092 _scan_top = top();
1093 }
1095 void G1OffsetTableContigSpace::safe_object_iterate(ObjectClosure* blk) {
1096 object_iterate(blk);
1097 }
1099 void G1OffsetTableContigSpace::object_iterate(ObjectClosure* blk) {
1100 HeapWord* p = bottom();
1101 while (p < top()) {
1102 if (block_is_obj(p)) {
1103 blk->do_object(oop(p));
1104 }
1105 p += block_size(p);
1106 }
1107 }
1109 #define block_is_always_obj(q) true
1110 void G1OffsetTableContigSpace::prepare_for_compaction(CompactPoint* cp) {
1111 SCAN_AND_FORWARD(cp, top, block_is_always_obj, block_size);
1112 }
1113 #undef block_is_always_obj
1115 G1OffsetTableContigSpace::
1116 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
1117 MemRegion mr) :
1118 _offsets(sharedOffsetArray, mr),
1119 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
1120 _gc_time_stamp(0)
1121 {
1122 _offsets.set_space(this);
1123 }
1125 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
1126 CompactibleSpace::initialize(mr, clear_space, mangle_space);
1127 _top = bottom();
1128 _scan_top = bottom();
1129 set_saved_mark_word(NULL);
1130 reset_bot();
1131 }