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 {
295 _rem_set = new HeapRegionRemSet(bot, this);
296
297 initialize(mr);
298 }
299
300 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
301 assert(_rem_set->is_empty(), "Remembered set must be empty");
302
303 G1ContiguousSpace::initialize(mr, clear_space, mangle_space);
304
305 hr_clear(false /*par*/, false /*clear_space*/);
306 set_top(bottom());
307 record_timestamp();
308 }
309
310 void HeapRegion::report_region_type_change(G1HeapRegionTraceType::Type to) {
311 HeapRegionTracer::send_region_type_change(_hrm_index,
312 get_trace_type(),
313 to,
314 (uintptr_t)bottom(),
315 used(),
316 (uint)allocation_context());
317 }
318
319 CompactibleSpace* HeapRegion::next_compaction_space() const {
320 return G1CollectedHeap::heap()->next_compaction_region(this);
321 }
322
323 void HeapRegion::note_self_forwarding_removal_start(bool during_initial_mark,
324 bool during_conc_mark) {
325 // We always recreate the prev marking info and we'll explicitly
326 // mark all objects we find to be self-forwarded on the prev
327 // bitmap. So all objects need to be below PTAMS.
328 _prev_marked_bytes = 0;
329
330 if (during_initial_mark) {
331 // During initial-mark, we'll also explicitly mark all objects
332 // we find to be self-forwarded on the next bitmap. So all
333 // objects need to be below NTAMS.
334 _next_top_at_mark_start = top();
335 _next_marked_bytes = 0;
336 } else if (during_conc_mark) {
337 // During concurrent mark, all objects in the CSet (including
338 // the ones we find to be self-forwarded) are implicitly live.
339 // So all objects need to be above NTAMS.
340 _next_top_at_mark_start = bottom();
341 _next_marked_bytes = 0;
342 }
343 }
344
345 void HeapRegion::note_self_forwarding_removal_end(size_t marked_bytes) {
346 assert(marked_bytes <= used(),
347 "marked: " SIZE_FORMAT " used: " SIZE_FORMAT, marked_bytes, used());
348 _prev_top_at_mark_start = top();
349 _prev_marked_bytes = marked_bytes;
350 }
351
352 // Humongous objects are allocated directly in the old-gen. Need
353 // special handling for concurrent processing encountering an
354 // in-progress allocation.
355 static bool do_oops_on_card_in_humongous(MemRegion mr,
356 FilterOutOfRegionClosure* cl,
357 HeapRegion* hr,
358 G1CollectedHeap* g1h) {
359 assert(hr->is_humongous(), "precondition");
360 HeapRegion* sr = hr->humongous_start_region();
361 oop obj = oop(sr->bottom());
362
363 // If concurrent and klass_or_null is NULL, then space has been
364 // allocated but the object has not yet been published by setting
365 // the klass. That can only happen if the card is stale. However,
366 // we've already set the card clean, so we must return failure,
367 // since the allocating thread could have performed a write to the
368 // card that might be missed otherwise.
369 if (!g1h->is_gc_active() && (obj->klass_or_null_acquire() == NULL)) {
370 return false;
371 }
372
373 // We have a well-formed humongous object at the start of sr.
374 // Only filler objects follow a humongous object in the containing
375 // regions, and we can ignore those. So only process the one
376 // humongous object.
377 if (!g1h->is_obj_dead(obj, sr)) {
378 if (obj->is_objArray() || (sr->bottom() < mr.start())) {
379 // objArrays are always marked precisely, so limit processing
380 // with mr. Non-objArrays might be precisely marked, and since
381 // it's humongous it's worthwhile avoiding full processing.
382 // However, the card could be stale and only cover filler
383 // objects. That should be rare, so not worth checking for;
384 // instead let it fall out from the bounded iteration.
385 obj->oop_iterate(cl, mr);
386 } else {
387 // If obj is not an objArray and mr contains the start of the
388 // obj, then this could be an imprecise mark, and we need to
389 // process the entire object.
390 obj->oop_iterate(cl);
391 }
392 }
393 return true;
394 }
395
396 bool HeapRegion::oops_on_card_seq_iterate_careful(MemRegion mr,
397 FilterOutOfRegionClosure* cl) {
398 assert(MemRegion(bottom(), end()).contains(mr), "Card region not in heap region");
399 G1CollectedHeap* g1h = G1CollectedHeap::heap();
400
401 // Special handling for humongous regions.
402 if (is_humongous()) {
403 return do_oops_on_card_in_humongous(mr, cl, this, g1h);
404 }
405 assert(is_old(), "precondition");
406
407 // Because mr has been trimmed to what's been allocated in this
408 // region, the parts of the heap that are examined here are always
409 // parsable; there's no need to use klass_or_null to detect
410 // in-progress allocation.
411
412 // Cache the boundaries of the memory region in some const locals
413 HeapWord* const start = mr.start();
414 HeapWord* const end = mr.end();
415
416 // Find the obj that extends onto mr.start().
417 // Update BOT as needed while finding start of (possibly dead)
418 // object containing the start of the region.
419 HeapWord* cur = block_start(start);
420
421 #ifdef ASSERT
422 {
423 assert(cur <= start,
424 "cur: " PTR_FORMAT ", start: " PTR_FORMAT, p2i(cur), p2i(start));
425 HeapWord* next = cur + block_size(cur);
426 assert(start < next,
427 "start: " PTR_FORMAT ", next: " PTR_FORMAT, p2i(start), p2i(next));
428 }
429 #endif
430
431 do {
432 oop obj = oop(cur);
433 assert(obj->is_oop(true), "Not an oop at " PTR_FORMAT, p2i(cur));
434 assert(obj->klass_or_null() != NULL,
435 "Unparsable heap at " PTR_FORMAT, p2i(cur));
436
437 if (g1h->is_obj_dead(obj, this)) {
438 // Carefully step over dead object.
439 cur += block_size(cur);
440 } else {
441 // Step over live object, and process its references.
442 cur += obj->size();
443 // Non-objArrays are usually marked imprecise at the object
444 // start, in which case we need to iterate over them in full.
445 // objArrays are precisely marked, but can still be iterated
446 // over in full if completely covered.
447 if (!obj->is_objArray() || (((HeapWord*)obj) >= start && cur <= end)) {
448 obj->oop_iterate(cl);
449 } else {
450 obj->oop_iterate(cl, mr);
451 }
452 }
453 } while (cur < end);
454
455 return true;
456 }
457
458 // Code roots support
459
460 void HeapRegion::add_strong_code_root(nmethod* nm) {
461 HeapRegionRemSet* hrrs = rem_set();
462 hrrs->add_strong_code_root(nm);
463 }
464
465 void HeapRegion::add_strong_code_root_locked(nmethod* nm) {
466 assert_locked_or_safepoint(CodeCache_lock);
467 HeapRegionRemSet* hrrs = rem_set();
468 hrrs->add_strong_code_root_locked(nm);
469 }
470
471 void HeapRegion::remove_strong_code_root(nmethod* nm) {
472 HeapRegionRemSet* hrrs = rem_set();
473 hrrs->remove_strong_code_root(nm);
474 }
475
476 void HeapRegion::strong_code_roots_do(CodeBlobClosure* blk) const {
477 HeapRegionRemSet* hrrs = rem_set();
478 hrrs->strong_code_roots_do(blk);
479 }
480
481 class VerifyStrongCodeRootOopClosure: public OopClosure {
482 const HeapRegion* _hr;
483 bool _failures;
484 bool _has_oops_in_region;
485
486 template <class T> void do_oop_work(T* p) {
487 T heap_oop = oopDesc::load_heap_oop(p);
488 if (!oopDesc::is_null(heap_oop)) {
489 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
490
491 // Note: not all the oops embedded in the nmethod are in the
492 // current region. We only look at those which are.
493 if (_hr->is_in(obj)) {
494 // Object is in the region. Check that its less than top
495 if (_hr->top() <= (HeapWord*)obj) {
496 // Object is above top
497 log_error(gc, verify)("Object " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ") is above top " PTR_FORMAT,
498 p2i(obj), p2i(_hr->bottom()), p2i(_hr->end()), p2i(_hr->top()));
499 _failures = true;
500 return;
501 }
502 // Nmethod has at least one oop in the current region
503 _has_oops_in_region = true;
504 }
505 }
506 }
507
508 public:
509 VerifyStrongCodeRootOopClosure(const HeapRegion* hr):
510 _hr(hr), _failures(false), _has_oops_in_region(false) {}
511
512 void do_oop(narrowOop* p) { do_oop_work(p); }
513 void do_oop(oop* p) { do_oop_work(p); }
514
515 bool failures() { return _failures; }
516 bool has_oops_in_region() { return _has_oops_in_region; }
517 };
518
519 class VerifyStrongCodeRootCodeBlobClosure: public CodeBlobClosure {
520 const HeapRegion* _hr;
521 bool _failures;
522 public:
523 VerifyStrongCodeRootCodeBlobClosure(const HeapRegion* hr) :
524 _hr(hr), _failures(false) {}
525
526 void do_code_blob(CodeBlob* cb) {
527 nmethod* nm = (cb == NULL) ? NULL : cb->as_compiled_method()->as_nmethod_or_null();
528 if (nm != NULL) {
529 // Verify that the nemthod is live
530 if (!nm->is_alive()) {
531 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has dead nmethod " PTR_FORMAT " in its strong code roots",
532 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
533 _failures = true;
534 } else {
535 VerifyStrongCodeRootOopClosure oop_cl(_hr);
536 nm->oops_do(&oop_cl);
537 if (!oop_cl.has_oops_in_region()) {
538 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has nmethod " PTR_FORMAT " in its strong code roots with no pointers into region",
539 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
540 _failures = true;
541 } else if (oop_cl.failures()) {
542 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] has other failures for nmethod " PTR_FORMAT,
543 p2i(_hr->bottom()), p2i(_hr->end()), p2i(nm));
544 _failures = true;
545 }
546 }
547 }
548 }
549
550 bool failures() { return _failures; }
551 };
552
553 void HeapRegion::verify_strong_code_roots(VerifyOption vo, bool* failures) const {
554 if (!G1VerifyHeapRegionCodeRoots) {
555 // We're not verifying code roots.
556 return;
557 }
558 if (vo == VerifyOption_G1UseMarkWord) {
559 // Marking verification during a full GC is performed after class
560 // unloading, code cache unloading, etc so the strong code roots
561 // attached to each heap region are in an inconsistent state. They won't
562 // be consistent until the strong code roots are rebuilt after the
563 // actual GC. Skip verifying the strong code roots in this particular
564 // time.
565 assert(VerifyDuringGC, "only way to get here");
566 return;
567 }
568
569 HeapRegionRemSet* hrrs = rem_set();
570 size_t strong_code_roots_length = hrrs->strong_code_roots_list_length();
571
572 // if this region is empty then there should be no entries
573 // on its strong code root list
574 if (is_empty()) {
575 if (strong_code_roots_length > 0) {
576 log_error(gc, verify)("region [" PTR_FORMAT "," PTR_FORMAT "] is empty but has " SIZE_FORMAT " code root entries",
577 p2i(bottom()), p2i(end()), strong_code_roots_length);
578 *failures = true;
579 }
580 return;
581 }
582
583 if (is_continues_humongous()) {
584 if (strong_code_roots_length > 0) {
585 log_error(gc, verify)("region " HR_FORMAT " is a continuation of a humongous region but has " SIZE_FORMAT " code root entries",
586 HR_FORMAT_PARAMS(this), strong_code_roots_length);
587 *failures = true;
588 }
589 return;
590 }
591
592 VerifyStrongCodeRootCodeBlobClosure cb_cl(this);
593 strong_code_roots_do(&cb_cl);
594
595 if (cb_cl.failures()) {
596 *failures = true;
597 }
598 }
599
600 void HeapRegion::print() const { print_on(tty); }
601 void HeapRegion::print_on(outputStream* st) const {
602 st->print("|%4u", this->_hrm_index);
603 st->print("|" PTR_FORMAT ", " PTR_FORMAT ", " PTR_FORMAT,
604 p2i(bottom()), p2i(top()), p2i(end()));
605 st->print("|%3d%%", (int) ((double) used() * 100 / capacity()));
606 st->print("|%2s", get_short_type_str());
607 if (in_collection_set()) {
608 st->print("|CS");
609 } else {
610 st->print("| ");
611 }
612 st->print("|TS%3u", _gc_time_stamp);
613 st->print("|AC%3u", allocation_context());
614 st->print_cr("|TAMS " PTR_FORMAT ", " PTR_FORMAT "|",
615 p2i(prev_top_at_mark_start()), p2i(next_top_at_mark_start()));
616 }
617
618 class G1VerificationClosure : public OopClosure {
619 protected:
620 G1CollectedHeap* _g1h;
621 CardTableModRefBS* _bs;
622 oop _containing_obj;
623 bool _failures;
624 int _n_failures;
625 VerifyOption _vo;
626 public:
627 // _vo == UsePrevMarking -> use "prev" marking information,
628 // _vo == UseNextMarking -> use "next" marking information,
629 // _vo == UseMarkWord -> use mark word from object header.
630 G1VerificationClosure(G1CollectedHeap* g1h, VerifyOption vo) :
631 _g1h(g1h), _bs(barrier_set_cast<CardTableModRefBS>(g1h->barrier_set())),
632 _containing_obj(NULL), _failures(false), _n_failures(0), _vo(vo) {
633 }
634
635 void set_containing_obj(oop obj) {
636 _containing_obj = obj;
637 }
638
639 bool failures() { return _failures; }
640 int n_failures() { return _n_failures; }
641
642 void print_object(outputStream* out, oop obj) {
643 #ifdef PRODUCT
644 Klass* k = obj->klass();
645 const char* class_name = k->external_name();
646 out->print_cr("class name %s", class_name);
647 #else // PRODUCT
648 obj->print_on(out);
649 #endif // PRODUCT
650 }
651 };
652
653 class VerifyLiveClosure : public G1VerificationClosure {
654 public:
655 VerifyLiveClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
656 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
657 virtual void do_oop(oop* p) { do_oop_work(p); }
658
659 template <class T>
660 void do_oop_work(T* p) {
661 assert(_containing_obj != NULL, "Precondition");
662 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
663 "Precondition");
664 verify_liveness(p);
665 }
666
667 template <class T>
668 void verify_liveness(T* p) {
669 T heap_oop = oopDesc::load_heap_oop(p);
670 Log(gc, verify) log;
671 if (!oopDesc::is_null(heap_oop)) {
672 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
673 bool failed = false;
674 if (!_g1h->is_in_closed_subset(obj) || _g1h->is_obj_dead_cond(obj, _vo)) {
675 MutexLockerEx x(ParGCRareEvent_lock,
676 Mutex::_no_safepoint_check_flag);
677
678 if (!_failures) {
679 log.error("----------");
680 }
681 ResourceMark rm;
682 if (!_g1h->is_in_closed_subset(obj)) {
683 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
684 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
685 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
686 print_object(log.error_stream(), _containing_obj);
687 log.error("points to obj " PTR_FORMAT " not in the heap", p2i(obj));
688 } else {
689 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
690 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
691 log.error("Field " PTR_FORMAT " of live obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
692 p2i(p), p2i(_containing_obj), p2i(from->bottom()), p2i(from->end()));
693 print_object(log.error_stream(), _containing_obj);
694 log.error("points to dead obj " PTR_FORMAT " in region [" PTR_FORMAT ", " PTR_FORMAT ")",
695 p2i(obj), p2i(to->bottom()), p2i(to->end()));
696 print_object(log.error_stream(), obj);
697 }
698 log.error("----------");
699 _failures = true;
700 failed = true;
701 _n_failures++;
702 }
703 }
704 }
705 };
706
707 class VerifyRemSetClosure : public G1VerificationClosure {
708 public:
709 VerifyRemSetClosure(G1CollectedHeap* g1h, VerifyOption vo) : G1VerificationClosure(g1h, vo) {}
710 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
711 virtual void do_oop(oop* p) { do_oop_work(p); }
712
713 template <class T>
714 void do_oop_work(T* p) {
715 assert(_containing_obj != NULL, "Precondition");
716 assert(!_g1h->is_obj_dead_cond(_containing_obj, _vo),
717 "Precondition");
718 verify_remembered_set(p);
719 }
720
721 template <class T>
722 void verify_remembered_set(T* p) {
723 T heap_oop = oopDesc::load_heap_oop(p);
724 Log(gc, verify) log;
725 if (!oopDesc::is_null(heap_oop)) {
726 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
727 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
728 HeapRegion* to = _g1h->heap_region_containing(obj);
729 if (from != NULL && to != NULL &&
730 from != to &&
731 !to->is_pinned()) {
732 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
733 jbyte cv_field = *_bs->byte_for_const(p);
734 const jbyte dirty = CardTableModRefBS::dirty_card_val();
735
736 bool is_bad = !(from->is_young()
737 || to->rem_set()->contains_reference(p)
738 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
739 (_containing_obj->is_objArray() ?
740 cv_field == dirty
741 : cv_obj == dirty || cv_field == dirty));
742 if (is_bad) {
743 MutexLockerEx x(ParGCRareEvent_lock,
744 Mutex::_no_safepoint_check_flag);
745
746 if (!_failures) {
747 log.error("----------");
748 }
749 log.error("Missing rem set entry:");
750 log.error("Field " PTR_FORMAT " of obj " PTR_FORMAT ", in region " HR_FORMAT,
751 p2i(p), p2i(_containing_obj), HR_FORMAT_PARAMS(from));
752 ResourceMark rm;
753 _containing_obj->print_on(log.error_stream());
754 log.error("points to obj " PTR_FORMAT " in region " HR_FORMAT, p2i(obj), HR_FORMAT_PARAMS(to));
755 if (obj->is_oop()) {
756 obj->print_on(log.error_stream());
757 }
758 log.error("Obj head CTE = %d, field CTE = %d.", cv_obj, cv_field);
759 log.error("----------");
760 _failures = true;
761 _n_failures++;
762 }
763 }
764 }
765 }
766 };
767
768 // This really ought to be commoned up into OffsetTableContigSpace somehow.
769 // We would need a mechanism to make that code skip dead objects.
770
771 void HeapRegion::verify(VerifyOption vo,
772 bool* failures) const {
773 G1CollectedHeap* g1 = G1CollectedHeap::heap();
774 *failures = false;
775 HeapWord* p = bottom();
776 HeapWord* prev_p = NULL;
777 VerifyLiveClosure vl_cl(g1, vo);
778 VerifyRemSetClosure vr_cl(g1, vo);
779 bool is_region_humongous = is_humongous();
780 size_t object_num = 0;
781 while (p < top()) {
782 oop obj = oop(p);
783 size_t obj_size = block_size(p);
784 object_num += 1;
785
786 if (!g1->is_obj_dead_cond(obj, this, vo)) {
787 if (obj->is_oop()) {
788 Klass* klass = obj->klass();
789 bool is_metaspace_object = Metaspace::contains(klass) ||
790 (vo == VerifyOption_G1UsePrevMarking &&
791 ClassLoaderDataGraph::unload_list_contains(klass));
792 if (!is_metaspace_object) {
793 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
794 "not metadata", p2i(klass), p2i(obj));
795 *failures = true;
796 return;
797 } else if (!klass->is_klass()) {
798 log_error(gc, verify)("klass " PTR_FORMAT " of object " PTR_FORMAT " "
799 "not a klass", p2i(klass), p2i(obj));
800 *failures = true;
801 return;
802 } else {
803 vl_cl.set_containing_obj(obj);
804 if (!g1->collector_state()->full_collection() || G1VerifyRSetsDuringFullGC) {
805 // verify liveness and rem_set
806 vr_cl.set_containing_obj(obj);
807 G1Mux2Closure mux(&vl_cl, &vr_cl);
808 obj->oop_iterate_no_header(&mux);
809
810 if (vr_cl.failures()) {
811 *failures = true;
812 }
813 if (G1MaxVerifyFailures >= 0 &&
814 vr_cl.n_failures() >= G1MaxVerifyFailures) {
815 return;
816 }
817 } else {
818 // verify only liveness
819 obj->oop_iterate_no_header(&vl_cl);
820 }
821 if (vl_cl.failures()) {
822 *failures = true;
823 }
824 if (G1MaxVerifyFailures >= 0 &&
825 vl_cl.n_failures() >= G1MaxVerifyFailures) {
826 return;
827 }
828 }
829 } else {
830 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
831 *failures = true;
832 return;
833 }
834 }
835 prev_p = p;
836 p += obj_size;
837 }
838
839 if (!is_young() && !is_empty()) {
840 _bot_part.verify();
841 }
842
843 if (is_region_humongous) {
844 oop obj = oop(this->humongous_start_region()->bottom());
845 if ((HeapWord*)obj > bottom() || (HeapWord*)obj + obj->size() < bottom()) {
846 log_error(gc, verify)("this humongous region is not part of its' humongous object " PTR_FORMAT, p2i(obj));
847 *failures = true;
848 return;
849 }
850 }
851
852 if (!is_region_humongous && p != top()) {
853 log_error(gc, verify)("end of last object " PTR_FORMAT " "
854 "does not match top " PTR_FORMAT, p2i(p), p2i(top()));
855 *failures = true;
856 return;
857 }
858
859 HeapWord* the_end = end();
860 // Do some extra BOT consistency checking for addresses in the
861 // range [top, end). BOT look-ups in this range should yield
862 // top. No point in doing that if top == end (there's nothing there).
863 if (p < the_end) {
864 // Look up top
865 HeapWord* addr_1 = p;
866 HeapWord* b_start_1 = _bot_part.block_start_const(addr_1);
867 if (b_start_1 != p) {
868 log_error(gc, verify)("BOT look up for top: " PTR_FORMAT " "
869 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
870 p2i(addr_1), p2i(b_start_1), p2i(p));
871 *failures = true;
872 return;
873 }
874
875 // Look up top + 1
876 HeapWord* addr_2 = p + 1;
877 if (addr_2 < the_end) {
878 HeapWord* b_start_2 = _bot_part.block_start_const(addr_2);
879 if (b_start_2 != p) {
880 log_error(gc, verify)("BOT look up for top + 1: " PTR_FORMAT " "
881 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
882 p2i(addr_2), p2i(b_start_2), p2i(p));
883 *failures = true;
884 return;
885 }
886 }
887
888 // Look up an address between top and end
889 size_t diff = pointer_delta(the_end, p) / 2;
890 HeapWord* addr_3 = p + diff;
891 if (addr_3 < the_end) {
892 HeapWord* b_start_3 = _bot_part.block_start_const(addr_3);
893 if (b_start_3 != p) {
894 log_error(gc, verify)("BOT look up for top + diff: " PTR_FORMAT " "
895 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
896 p2i(addr_3), p2i(b_start_3), p2i(p));
897 *failures = true;
898 return;
899 }
900 }
901
902 // Look up end - 1
903 HeapWord* addr_4 = the_end - 1;
904 HeapWord* b_start_4 = _bot_part.block_start_const(addr_4);
905 if (b_start_4 != p) {
906 log_error(gc, verify)("BOT look up for end - 1: " PTR_FORMAT " "
907 " yielded " PTR_FORMAT ", expecting " PTR_FORMAT,
908 p2i(addr_4), p2i(b_start_4), p2i(p));
909 *failures = true;
910 return;
911 }
912 }
913
914 verify_strong_code_roots(vo, failures);
915 }
916
917 void HeapRegion::verify() const {
918 bool dummy = false;
919 verify(VerifyOption_G1UsePrevMarking, /* failures */ &dummy);
920 }
921
922 void HeapRegion::verify_rem_set(VerifyOption vo, bool* failures) const {
923 G1CollectedHeap* g1 = G1CollectedHeap::heap();
924 *failures = false;
925 HeapWord* p = bottom();
926 HeapWord* prev_p = NULL;
927 VerifyRemSetClosure vr_cl(g1, vo);
928 while (p < top()) {
929 oop obj = oop(p);
930 size_t obj_size = block_size(p);
931
932 if (!g1->is_obj_dead_cond(obj, this, vo)) {
933 if (obj->is_oop()) {
934 vr_cl.set_containing_obj(obj);
935 obj->oop_iterate_no_header(&vr_cl);
936
937 if (vr_cl.failures()) {
938 *failures = true;
939 }
940 if (G1MaxVerifyFailures >= 0 &&
941 vr_cl.n_failures() >= G1MaxVerifyFailures) {
942 return;
943 }
944 } else {
945 log_error(gc, verify)(PTR_FORMAT " not an oop", p2i(obj));
946 *failures = true;
947 return;
948 }
949 }
950
951 prev_p = p;
952 p += obj_size;
953 }
954 }
955
956 void HeapRegion::verify_rem_set() const {
957 bool failures = false;
958 verify_rem_set(VerifyOption_G1UsePrevMarking, &failures);
959 guarantee(!failures, "HeapRegion RemSet verification failed");
960 }
961
962 void HeapRegion::prepare_for_compaction(CompactPoint* cp) {
963 scan_and_forward(this, cp);
964 }
965
966 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
967 // away eventually.
968
969 void G1ContiguousSpace::clear(bool mangle_space) {
970 set_top(bottom());
971 _scan_top = bottom();
972 CompactibleSpace::clear(mangle_space);
973 reset_bot();
974 }
975
976 #ifndef PRODUCT
977 void G1ContiguousSpace::mangle_unused_area() {
978 mangle_unused_area_complete();
979 }
980
981 void G1ContiguousSpace::mangle_unused_area_complete() {
982 SpaceMangler::mangle_region(MemRegion(top(), end()));
983 }
984 #endif
985
986 void G1ContiguousSpace::print() const {
987 print_short();
988 tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
989 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
990 p2i(bottom()), p2i(top()), p2i(_bot_part.threshold()), p2i(end()));
991 }
992
993 HeapWord* G1ContiguousSpace::initialize_threshold() {
994 return _bot_part.initialize_threshold();
995 }
996
997 HeapWord* G1ContiguousSpace::cross_threshold(HeapWord* start,
998 HeapWord* end) {
999 _bot_part.alloc_block(start, end);
1000 return _bot_part.threshold();
1001 }
1002
1003 HeapWord* G1ContiguousSpace::scan_top() const {
1004 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1005 HeapWord* local_top = top();
1006 OrderAccess::loadload();
1007 const unsigned local_time_stamp = _gc_time_stamp;
1008 assert(local_time_stamp <= g1h->get_gc_time_stamp(), "invariant");
1009 if (local_time_stamp < g1h->get_gc_time_stamp()) {
1010 return local_top;
1011 } else {
1012 return _scan_top;
1013 }
1014 }
1015
1016 void G1ContiguousSpace::record_timestamp() {
1017 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1018 uint curr_gc_time_stamp = g1h->get_gc_time_stamp();
1019
1020 if (_gc_time_stamp < curr_gc_time_stamp) {
1021 // Setting the time stamp here tells concurrent readers to look at
1022 // scan_top to know the maximum allowed address to look at.
1023
1024 // scan_top should be bottom for all regions except for the
1025 // retained old alloc region which should have scan_top == top
1026 HeapWord* st = _scan_top;
1027 guarantee(st == _bottom || st == _top, "invariant");
1028
1029 _gc_time_stamp = curr_gc_time_stamp;
1030 }
1031 }
1032
1033 void G1ContiguousSpace::record_retained_region() {
1034 // scan_top is the maximum address where it's safe for the next gc to
1035 // scan this region.
1036 _scan_top = top();
1037 }
1038
1039 void G1ContiguousSpace::safe_object_iterate(ObjectClosure* blk) {
1040 object_iterate(blk);
1041 }
1042
1043 void G1ContiguousSpace::object_iterate(ObjectClosure* blk) {
1044 HeapWord* p = bottom();
1045 while (p < top()) {
1046 if (block_is_obj(p)) {
1047 blk->do_object(oop(p));
1048 }
1049 p += block_size(p);
1050 }
1051 }
1052
1053 G1ContiguousSpace::G1ContiguousSpace(G1BlockOffsetTable* bot) :
1054 _bot_part(bot, this),
1055 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
1056 _gc_time_stamp(0)
1057 {
1058 }
1059
1060 void G1ContiguousSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
1061 CompactibleSpace::initialize(mr, clear_space, mangle_space);
1062 _top = bottom();
1063 _scan_top = bottom();
1064 set_saved_mark_word(NULL);
1065 reset_bot();
1066 }
1067