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