1 /*
2 * Copyright (c) 2001, 2010, 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 "gc_implementation/g1/concurrentZFThread.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/heapRegionRemSet.hpp"
32 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
33 #include "memory/genOopClosures.inline.hpp"
34 #include "memory/iterator.hpp"
35 #include "oops/oop.inline.hpp"
36
37 int HeapRegion::LogOfHRGrainBytes = 0;
38 int HeapRegion::LogOfHRGrainWords = 0;
39 int HeapRegion::GrainBytes = 0;
40 int HeapRegion::GrainWords = 0;
41 int HeapRegion::CardsPerRegion = 0;
42
43 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
44 HeapRegion* hr, OopClosure* cl,
45 CardTableModRefBS::PrecisionStyle precision,
46 FilterKind fk) :
47 ContiguousSpaceDCTOC(hr, cl, precision, NULL),
48 _hr(hr), _fk(fk), _g1(g1)
49 {}
50
51 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
52 OopClosure* oc) :
53 _r_bottom(r->bottom()), _r_end(r->end()),
54 _oc(oc), _out_of_region(0)
55 {}
56
57 class VerifyLiveClosure: public OopClosure {
58 private:
59 G1CollectedHeap* _g1h;
60 CardTableModRefBS* _bs;
61 oop _containing_obj;
62 bool _failures;
63 int _n_failures;
64 bool _use_prev_marking;
65 public:
66 // use_prev_marking == true -> use "prev" marking information,
67 // use_prev_marking == false -> use "next" marking information
68 VerifyLiveClosure(G1CollectedHeap* g1h, bool use_prev_marking) :
69 _g1h(g1h), _bs(NULL), _containing_obj(NULL),
70 _failures(false), _n_failures(0), _use_prev_marking(use_prev_marking)
71 {
72 BarrierSet* bs = _g1h->barrier_set();
73 if (bs->is_a(BarrierSet::CardTableModRef))
74 _bs = (CardTableModRefBS*)bs;
75 }
76
77 void set_containing_obj(oop obj) {
78 _containing_obj = obj;
79 }
80
81 bool failures() { return _failures; }
82 int n_failures() { return _n_failures; }
83
84 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
85 virtual void do_oop( oop* p) { do_oop_work(p); }
86
87 void print_object(outputStream* out, oop obj) {
88 #ifdef PRODUCT
89 klassOop k = obj->klass();
90 const char* class_name = instanceKlass::cast(k)->external_name();
91 out->print_cr("class name %s", class_name);
92 #else // PRODUCT
93 obj->print_on(out);
94 #endif // PRODUCT
95 }
96
97 template <class T> void do_oop_work(T* p) {
98 assert(_containing_obj != NULL, "Precondition");
99 assert(!_g1h->is_obj_dead_cond(_containing_obj, _use_prev_marking),
100 "Precondition");
101 T heap_oop = oopDesc::load_heap_oop(p);
102 if (!oopDesc::is_null(heap_oop)) {
103 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
104 bool failed = false;
105 if (!_g1h->is_in_closed_subset(obj) ||
106 _g1h->is_obj_dead_cond(obj, _use_prev_marking)) {
107 if (!_failures) {
108 gclog_or_tty->print_cr("");
109 gclog_or_tty->print_cr("----------");
110 }
111 if (!_g1h->is_in_closed_subset(obj)) {
112 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
113 gclog_or_tty->print_cr("Field "PTR_FORMAT
114 " of live obj "PTR_FORMAT" in region "
115 "["PTR_FORMAT", "PTR_FORMAT")",
116 p, (void*) _containing_obj,
117 from->bottom(), from->end());
118 print_object(gclog_or_tty, _containing_obj);
119 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" not in the heap",
120 (void*) obj);
121 } else {
122 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
123 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
124 gclog_or_tty->print_cr("Field "PTR_FORMAT
125 " of live obj "PTR_FORMAT" in region "
126 "["PTR_FORMAT", "PTR_FORMAT")",
127 p, (void*) _containing_obj,
128 from->bottom(), from->end());
129 print_object(gclog_or_tty, _containing_obj);
130 gclog_or_tty->print_cr("points to dead obj "PTR_FORMAT" in region "
131 "["PTR_FORMAT", "PTR_FORMAT")",
132 (void*) obj, to->bottom(), to->end());
133 print_object(gclog_or_tty, obj);
134 }
135 gclog_or_tty->print_cr("----------");
136 _failures = true;
137 failed = true;
138 _n_failures++;
139 }
140
141 if (!_g1h->full_collection()) {
142 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
143 HeapRegion* to = _g1h->heap_region_containing(obj);
144 if (from != NULL && to != NULL &&
145 from != to &&
146 !to->isHumongous()) {
147 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
148 jbyte cv_field = *_bs->byte_for_const(p);
149 const jbyte dirty = CardTableModRefBS::dirty_card_val();
150
151 bool is_bad = !(from->is_young()
152 || to->rem_set()->contains_reference(p)
153 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
154 (_containing_obj->is_objArray() ?
155 cv_field == dirty
156 : cv_obj == dirty || cv_field == dirty));
157 if (is_bad) {
158 if (!_failures) {
159 gclog_or_tty->print_cr("");
160 gclog_or_tty->print_cr("----------");
161 }
162 gclog_or_tty->print_cr("Missing rem set entry:");
163 gclog_or_tty->print_cr("Field "PTR_FORMAT
164 " of obj "PTR_FORMAT
165 ", in region %d ["PTR_FORMAT
166 ", "PTR_FORMAT"),",
167 p, (void*) _containing_obj,
168 from->hrs_index(),
169 from->bottom(),
170 from->end());
171 _containing_obj->print_on(gclog_or_tty);
172 gclog_or_tty->print_cr("points to obj "PTR_FORMAT
173 " in region %d ["PTR_FORMAT
174 ", "PTR_FORMAT").",
175 (void*) obj, to->hrs_index(),
176 to->bottom(), to->end());
177 obj->print_on(gclog_or_tty);
178 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
179 cv_obj, cv_field);
180 gclog_or_tty->print_cr("----------");
181 _failures = true;
182 if (!failed) _n_failures++;
183 }
184 }
185 }
186 }
187 }
188 };
189
190 template<class ClosureType>
191 HeapWord* walk_mem_region_loop(ClosureType* cl, G1CollectedHeap* g1h,
192 HeapRegion* hr,
193 HeapWord* cur, HeapWord* top) {
194 oop cur_oop = oop(cur);
195 int oop_size = cur_oop->size();
196 HeapWord* next_obj = cur + oop_size;
197 while (next_obj < top) {
198 // Keep filtering the remembered set.
199 if (!g1h->is_obj_dead(cur_oop, hr)) {
200 // Bottom lies entirely below top, so we can call the
201 // non-memRegion version of oop_iterate below.
202 cur_oop->oop_iterate(cl);
203 }
204 cur = next_obj;
205 cur_oop = oop(cur);
206 oop_size = cur_oop->size();
207 next_obj = cur + oop_size;
208 }
209 return cur;
210 }
211
212 void HeapRegionDCTOC::walk_mem_region_with_cl(MemRegion mr,
213 HeapWord* bottom,
214 HeapWord* top,
215 OopClosure* cl) {
216 G1CollectedHeap* g1h = _g1;
217
218 int oop_size;
219
220 OopClosure* cl2 = cl;
221 FilterIntoCSClosure intoCSFilt(this, g1h, cl);
222 FilterOutOfRegionClosure outOfRegionFilt(_hr, cl);
223 switch (_fk) {
224 case IntoCSFilterKind: cl2 = &intoCSFilt; break;
225 case OutOfRegionFilterKind: cl2 = &outOfRegionFilt; break;
226 }
227
228 // Start filtering what we add to the remembered set. If the object is
229 // not considered dead, either because it is marked (in the mark bitmap)
230 // or it was allocated after marking finished, then we add it. Otherwise
231 // we can safely ignore the object.
232 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
233 oop_size = oop(bottom)->oop_iterate(cl2, mr);
234 } else {
235 oop_size = oop(bottom)->size();
236 }
237
238 bottom += oop_size;
239
240 if (bottom < top) {
241 // We replicate the loop below for several kinds of possible filters.
242 switch (_fk) {
243 case NoFilterKind:
244 bottom = walk_mem_region_loop(cl, g1h, _hr, bottom, top);
245 break;
246 case IntoCSFilterKind: {
247 FilterIntoCSClosure filt(this, g1h, cl);
248 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
249 break;
250 }
251 case OutOfRegionFilterKind: {
252 FilterOutOfRegionClosure filt(_hr, cl);
253 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
254 break;
255 }
256 default:
257 ShouldNotReachHere();
258 }
259
260 // Last object. Need to do dead-obj filtering here too.
261 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
262 oop(bottom)->oop_iterate(cl2, mr);
263 }
264 }
265 }
266
267 // Minimum region size; we won't go lower than that.
268 // We might want to decrease this in the future, to deal with small
269 // heaps a bit more efficiently.
270 #define MIN_REGION_SIZE ( 1024 * 1024 )
271
272 // Maximum region size; we don't go higher than that. There's a good
273 // reason for having an upper bound. We don't want regions to get too
274 // large, otherwise cleanup's effectiveness would decrease as there
275 // will be fewer opportunities to find totally empty regions after
276 // marking.
277 #define MAX_REGION_SIZE ( 32 * 1024 * 1024 )
278
279 // The automatic region size calculation will try to have around this
280 // many regions in the heap (based on the min heap size).
281 #define TARGET_REGION_NUMBER 2048
282
283 void HeapRegion::setup_heap_region_size(uintx min_heap_size) {
284 // region_size in bytes
285 uintx region_size = G1HeapRegionSize;
286 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
287 // We base the automatic calculation on the min heap size. This
288 // can be problematic if the spread between min and max is quite
289 // wide, imagine -Xms128m -Xmx32g. But, if we decided it based on
290 // the max size, the region size might be way too large for the
291 // min size. Either way, some users might have to set the region
292 // size manually for some -Xms / -Xmx combos.
293
294 region_size = MAX2(min_heap_size / TARGET_REGION_NUMBER,
295 (uintx) MIN_REGION_SIZE);
296 }
297
298 int region_size_log = log2_long((jlong) region_size);
299 // Recalculate the region size to make sure it's a power of
300 // 2. This means that region_size is the largest power of 2 that's
301 // <= what we've calculated so far.
302 region_size = ((uintx)1 << region_size_log);
303
304 // Now make sure that we don't go over or under our limits.
305 if (region_size < MIN_REGION_SIZE) {
306 region_size = MIN_REGION_SIZE;
307 } else if (region_size > MAX_REGION_SIZE) {
308 region_size = MAX_REGION_SIZE;
309 }
310
311 // And recalculate the log.
312 region_size_log = log2_long((jlong) region_size);
313
314 // Now, set up the globals.
315 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
316 LogOfHRGrainBytes = region_size_log;
317
318 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
319 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
320
321 guarantee(GrainBytes == 0, "we should only set it once");
322 // The cast to int is safe, given that we've bounded region_size by
323 // MIN_REGION_SIZE and MAX_REGION_SIZE.
324 GrainBytes = (int) region_size;
325
326 guarantee(GrainWords == 0, "we should only set it once");
327 GrainWords = GrainBytes >> LogHeapWordSize;
328 guarantee(1 << LogOfHRGrainWords == GrainWords, "sanity");
329
330 guarantee(CardsPerRegion == 0, "we should only set it once");
331 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
332 }
333
334 void HeapRegion::reset_after_compaction() {
335 G1OffsetTableContigSpace::reset_after_compaction();
336 // After a compaction the mark bitmap is invalid, so we must
337 // treat all objects as being inside the unmarked area.
338 zero_marked_bytes();
339 init_top_at_mark_start();
340 }
341
342 DirtyCardToOopClosure*
343 HeapRegion::new_dcto_closure(OopClosure* cl,
344 CardTableModRefBS::PrecisionStyle precision,
345 HeapRegionDCTOC::FilterKind fk) {
346 return new HeapRegionDCTOC(G1CollectedHeap::heap(),
347 this, cl, precision, fk);
348 }
349
350 void HeapRegion::hr_clear(bool par, bool clear_space) {
351 _humongous_type = NotHumongous;
352 _humongous_start_region = NULL;
353 _in_collection_set = false;
354 _is_gc_alloc_region = false;
355
356 // Age stuff (if parallel, this will be done separately, since it needs
357 // to be sequential).
358 G1CollectedHeap* g1h = G1CollectedHeap::heap();
359
360 set_young_index_in_cset(-1);
361 uninstall_surv_rate_group();
362 set_young_type(NotYoung);
363
364 // In case it had been the start of a humongous sequence, reset its end.
365 set_end(_orig_end);
366
367 if (!par) {
368 // If this is parallel, this will be done later.
369 HeapRegionRemSet* hrrs = rem_set();
370 if (hrrs != NULL) hrrs->clear();
371 _claimed = InitialClaimValue;
372 }
373 zero_marked_bytes();
374 set_sort_index(-1);
375
376 _offsets.resize(HeapRegion::GrainWords);
377 init_top_at_mark_start();
378 if (clear_space) clear(SpaceDecorator::Mangle);
379 }
380
381 // <PREDICTION>
382 void HeapRegion::calc_gc_efficiency() {
383 G1CollectedHeap* g1h = G1CollectedHeap::heap();
384 _gc_efficiency = (double) garbage_bytes() /
385 g1h->predict_region_elapsed_time_ms(this, false);
386 }
387 // </PREDICTION>
388
389 void HeapRegion::set_startsHumongous() {
390 _humongous_type = StartsHumongous;
391 _humongous_start_region = this;
392 assert(end() == _orig_end, "Should be normal before alloc.");
393 }
394
395 bool HeapRegion::claimHeapRegion(jint claimValue) {
396 jint current = _claimed;
397 if (current != claimValue) {
398 jint res = Atomic::cmpxchg(claimValue, &_claimed, current);
399 if (res == current) {
400 return true;
401 }
402 }
403 return false;
404 }
405
406 HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) {
407 HeapWord* low = addr;
408 HeapWord* high = end();
409 while (low < high) {
410 size_t diff = pointer_delta(high, low);
411 // Must add one below to bias toward the high amount. Otherwise, if
412 // "high" were at the desired value, and "low" were one less, we
413 // would not converge on "high". This is not symmetric, because
414 // we set "high" to a block start, which might be the right one,
415 // which we don't do for "low".
416 HeapWord* middle = low + (diff+1)/2;
417 if (middle == high) return high;
418 HeapWord* mid_bs = block_start_careful(middle);
419 if (mid_bs < addr) {
420 low = middle;
421 } else {
422 high = mid_bs;
423 }
424 }
425 assert(low == high && low >= addr, "Didn't work.");
426 return low;
427 }
428
429 void HeapRegion::set_next_on_unclean_list(HeapRegion* r) {
430 assert(r == NULL || r->is_on_unclean_list(), "Malformed unclean list.");
431 _next_in_special_set = r;
432 }
433
434 void HeapRegion::set_on_unclean_list(bool b) {
435 _is_on_unclean_list = b;
436 }
437
438 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
439 G1OffsetTableContigSpace::initialize(mr, false, mangle_space);
440 hr_clear(false/*par*/, clear_space);
441 }
442 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
443 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
444 #endif // _MSC_VER
445
446
447 HeapRegion::
448 HeapRegion(G1BlockOffsetSharedArray* sharedOffsetArray,
449 MemRegion mr, bool is_zeroed)
450 : G1OffsetTableContigSpace(sharedOffsetArray, mr, is_zeroed),
451 _next_fk(HeapRegionDCTOC::NoFilterKind),
452 _hrs_index(-1),
453 _humongous_type(NotHumongous), _humongous_start_region(NULL),
454 _in_collection_set(false), _is_gc_alloc_region(false),
455 _is_on_free_list(false), _is_on_unclean_list(false),
456 _next_in_special_set(NULL), _orig_end(NULL),
457 _claimed(InitialClaimValue), _evacuation_failed(false),
458 _prev_marked_bytes(0), _next_marked_bytes(0), _sort_index(-1),
459 _young_type(NotYoung), _next_young_region(NULL),
460 _next_dirty_cards_region(NULL),
461 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
462 _rem_set(NULL), _zfs(NotZeroFilled),
463 _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
464 _predicted_bytes_to_copy(0)
465 {
466 _orig_end = mr.end();
467 // Note that initialize() will set the start of the unmarked area of the
468 // region.
469 this->initialize(mr, !is_zeroed, SpaceDecorator::Mangle);
470 set_top(bottom());
471 set_saved_mark();
472
473 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
474
475 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
476 // In case the region is allocated during a pause, note the top.
477 // We haven't done any counting on a brand new region.
478 _top_at_conc_mark_count = bottom();
479 }
480
481 class NextCompactionHeapRegionClosure: public HeapRegionClosure {
482 const HeapRegion* _target;
483 bool _target_seen;
484 HeapRegion* _last;
485 CompactibleSpace* _res;
486 public:
487 NextCompactionHeapRegionClosure(const HeapRegion* target) :
488 _target(target), _target_seen(false), _res(NULL) {}
489 bool doHeapRegion(HeapRegion* cur) {
490 if (_target_seen) {
491 if (!cur->isHumongous()) {
492 _res = cur;
493 return true;
494 }
495 } else if (cur == _target) {
496 _target_seen = true;
497 }
498 return false;
499 }
500 CompactibleSpace* result() { return _res; }
501 };
502
503 CompactibleSpace* HeapRegion::next_compaction_space() const {
504 G1CollectedHeap* g1h = G1CollectedHeap::heap();
505 // cast away const-ness
506 HeapRegion* r = (HeapRegion*) this;
507 NextCompactionHeapRegionClosure blk(r);
508 g1h->heap_region_iterate_from(r, &blk);
509 return blk.result();
510 }
511
512 void HeapRegion::set_continuesHumongous(HeapRegion* start) {
513 // The order is important here.
514 start->add_continuingHumongousRegion(this);
515 _humongous_type = ContinuesHumongous;
516 _humongous_start_region = start;
517 }
518
519 void HeapRegion::add_continuingHumongousRegion(HeapRegion* cont) {
520 // Must join the blocks of the current H region seq with the block of the
521 // added region.
522 offsets()->join_blocks(bottom(), cont->bottom());
523 arrayOop obj = (arrayOop)(bottom());
524 obj->set_length((int) (obj->length() + cont->capacity()/jintSize));
525 set_end(cont->end());
526 set_top(cont->end());
527 }
528
529 void HeapRegion::save_marks() {
530 set_saved_mark();
531 }
532
533 void HeapRegion::oops_in_mr_iterate(MemRegion mr, OopClosure* cl) {
534 HeapWord* p = mr.start();
535 HeapWord* e = mr.end();
536 oop obj;
537 while (p < e) {
538 obj = oop(p);
539 p += obj->oop_iterate(cl);
540 }
541 assert(p == e, "bad memregion: doesn't end on obj boundary");
542 }
543
544 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \
545 void HeapRegion::oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \
546 ContiguousSpace::oop_since_save_marks_iterate##nv_suffix(cl); \
547 }
548 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN)
549
550
551 void HeapRegion::oop_before_save_marks_iterate(OopClosure* cl) {
552 oops_in_mr_iterate(MemRegion(bottom(), saved_mark_word()), cl);
553 }
554
555 #ifdef DEBUG
556 HeapWord* HeapRegion::allocate(size_t size) {
557 jint state = zero_fill_state();
558 assert(!G1CollectedHeap::heap()->allocs_are_zero_filled() ||
559 zero_fill_is_allocated(),
560 "When ZF is on, only alloc in ZF'd regions");
561 return G1OffsetTableContigSpace::allocate(size);
562 }
563 #endif
564
565 void HeapRegion::set_zero_fill_state_work(ZeroFillState zfs) {
566 assert(ZF_mon->owned_by_self() ||
567 Universe::heap()->is_gc_active(),
568 "Must hold the lock or be a full GC to modify.");
569 #ifdef ASSERT
570 if (top() != bottom() && zfs != Allocated) {
571 ResourceMark rm;
572 stringStream region_str;
573 print_on(®ion_str);
574 assert(top() == bottom() || zfs == Allocated,
575 err_msg("Region must be empty, or we must be setting it to allocated. "
576 "_zfs=%d, zfs=%d, region: %s", _zfs, zfs, region_str.as_string()));
577 }
578 #endif
579 _zfs = zfs;
580 }
581
582 void HeapRegion::set_zero_fill_complete() {
583 set_zero_fill_state_work(ZeroFilled);
584 if (ZF_mon->owned_by_self()) {
585 ZF_mon->notify_all();
586 }
587 }
588
589
590 void HeapRegion::ensure_zero_filled() {
591 MutexLockerEx x(ZF_mon, Mutex::_no_safepoint_check_flag);
592 ensure_zero_filled_locked();
593 }
594
595 void HeapRegion::ensure_zero_filled_locked() {
596 assert(ZF_mon->owned_by_self(), "Precondition");
597 bool should_ignore_zf = SafepointSynchronize::is_at_safepoint();
598 assert(should_ignore_zf || Heap_lock->is_locked(),
599 "Either we're in a GC or we're allocating a region.");
600 switch (zero_fill_state()) {
601 case HeapRegion::NotZeroFilled:
602 set_zero_fill_in_progress(Thread::current());
603 {
604 ZF_mon->unlock();
605 Copy::fill_to_words(bottom(), capacity()/HeapWordSize);
606 ZF_mon->lock_without_safepoint_check();
607 }
608 // A trap.
609 guarantee(zero_fill_state() == HeapRegion::ZeroFilling
610 && zero_filler() == Thread::current(),
611 "AHA! Tell Dave D if you see this...");
612 set_zero_fill_complete();
613 // gclog_or_tty->print_cr("Did sync ZF.");
614 ConcurrentZFThread::note_sync_zfs();
615 break;
616 case HeapRegion::ZeroFilling:
617 if (should_ignore_zf) {
618 // We can "break" the lock and take over the work.
619 Copy::fill_to_words(bottom(), capacity()/HeapWordSize);
620 set_zero_fill_complete();
621 ConcurrentZFThread::note_sync_zfs();
622 break;
623 } else {
624 ConcurrentZFThread::wait_for_ZF_completed(this);
625 }
626 case HeapRegion::ZeroFilled:
627 // Nothing to do.
628 break;
629 case HeapRegion::Allocated:
630 guarantee(false, "Should not call on allocated regions.");
631 }
632 assert(zero_fill_state() == HeapRegion::ZeroFilled, "Post");
633 }
634
635 HeapWord*
636 HeapRegion::object_iterate_mem_careful(MemRegion mr,
637 ObjectClosure* cl) {
638 G1CollectedHeap* g1h = G1CollectedHeap::heap();
639 // We used to use "block_start_careful" here. But we're actually happy
640 // to update the BOT while we do this...
641 HeapWord* cur = block_start(mr.start());
642 mr = mr.intersection(used_region());
643 if (mr.is_empty()) return NULL;
644 // Otherwise, find the obj that extends onto mr.start().
645
646 assert(cur <= mr.start()
647 && (oop(cur)->klass_or_null() == NULL ||
648 cur + oop(cur)->size() > mr.start()),
649 "postcondition of block_start");
650 oop obj;
651 while (cur < mr.end()) {
652 obj = oop(cur);
653 if (obj->klass_or_null() == NULL) {
654 // Ran into an unparseable point.
655 return cur;
656 } else if (!g1h->is_obj_dead(obj)) {
657 cl->do_object(obj);
658 }
659 if (cl->abort()) return cur;
660 // The check above must occur before the operation below, since an
661 // abort might invalidate the "size" operation.
662 cur += obj->size();
663 }
664 return NULL;
665 }
666
667 HeapWord*
668 HeapRegion::
669 oops_on_card_seq_iterate_careful(MemRegion mr,
670 FilterOutOfRegionClosure* cl,
671 bool filter_young) {
672 G1CollectedHeap* g1h = G1CollectedHeap::heap();
673
674 // If we're within a stop-world GC, then we might look at a card in a
675 // GC alloc region that extends onto a GC LAB, which may not be
676 // parseable. Stop such at the "saved_mark" of the region.
677 if (G1CollectedHeap::heap()->is_gc_active()) {
678 mr = mr.intersection(used_region_at_save_marks());
679 } else {
680 mr = mr.intersection(used_region());
681 }
682 if (mr.is_empty()) return NULL;
683 // Otherwise, find the obj that extends onto mr.start().
684
685 // The intersection of the incoming mr (for the card) and the
686 // allocated part of the region is non-empty. This implies that
687 // we have actually allocated into this region. The code in
688 // G1CollectedHeap.cpp that allocates a new region sets the
689 // is_young tag on the region before allocating. Thus we
690 // safely know if this region is young.
691 if (is_young() && filter_young) {
692 return NULL;
693 }
694
695 assert(!is_young(), "check value of filter_young");
696
697 // We used to use "block_start_careful" here. But we're actually happy
698 // to update the BOT while we do this...
699 HeapWord* cur = block_start(mr.start());
700 assert(cur <= mr.start(), "Postcondition");
701
702 while (cur <= mr.start()) {
703 if (oop(cur)->klass_or_null() == NULL) {
704 // Ran into an unparseable point.
705 return cur;
706 }
707 // Otherwise...
708 int sz = oop(cur)->size();
709 if (cur + sz > mr.start()) break;
710 // Otherwise, go on.
711 cur = cur + sz;
712 }
713 oop obj;
714 obj = oop(cur);
715 // If we finish this loop...
716 assert(cur <= mr.start()
717 && obj->klass_or_null() != NULL
718 && cur + obj->size() > mr.start(),
719 "Loop postcondition");
720 if (!g1h->is_obj_dead(obj)) {
721 obj->oop_iterate(cl, mr);
722 }
723
724 HeapWord* next;
725 while (cur < mr.end()) {
726 obj = oop(cur);
727 if (obj->klass_or_null() == NULL) {
728 // Ran into an unparseable point.
729 return cur;
730 };
731 // Otherwise:
732 next = (cur + obj->size());
733 if (!g1h->is_obj_dead(obj)) {
734 if (next < mr.end()) {
735 obj->oop_iterate(cl);
736 } else {
737 // this obj spans the boundary. If it's an array, stop at the
738 // boundary.
739 if (obj->is_objArray()) {
740 obj->oop_iterate(cl, mr);
741 } else {
742 obj->oop_iterate(cl);
743 }
744 }
745 }
746 cur = next;
747 }
748 return NULL;
749 }
750
751 void HeapRegion::print() const { print_on(gclog_or_tty); }
752 void HeapRegion::print_on(outputStream* st) const {
753 if (isHumongous()) {
754 if (startsHumongous())
755 st->print(" HS");
756 else
757 st->print(" HC");
758 } else {
759 st->print(" ");
760 }
761 if (in_collection_set())
762 st->print(" CS");
763 else if (is_gc_alloc_region())
764 st->print(" A ");
765 else
766 st->print(" ");
767 if (is_young())
768 st->print(is_survivor() ? " SU" : " Y ");
769 else
770 st->print(" ");
771 if (is_empty())
772 st->print(" F");
773 else
774 st->print(" ");
775 st->print(" %5d", _gc_time_stamp);
776 st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT,
777 prev_top_at_mark_start(), next_top_at_mark_start());
778 G1OffsetTableContigSpace::print_on(st);
779 }
780
781 void HeapRegion::verify(bool allow_dirty) const {
782 bool dummy = false;
783 verify(allow_dirty, /* use_prev_marking */ true, /* failures */ &dummy);
784 }
785
786 #define OBJ_SAMPLE_INTERVAL 0
787 #define BLOCK_SAMPLE_INTERVAL 100
788
789 // This really ought to be commoned up into OffsetTableContigSpace somehow.
790 // We would need a mechanism to make that code skip dead objects.
791
792 void HeapRegion::verify(bool allow_dirty,
793 bool use_prev_marking,
794 bool* failures) const {
795 G1CollectedHeap* g1 = G1CollectedHeap::heap();
796 *failures = false;
797 HeapWord* p = bottom();
798 HeapWord* prev_p = NULL;
799 int objs = 0;
800 int blocks = 0;
801 VerifyLiveClosure vl_cl(g1, use_prev_marking);
802 bool is_humongous = isHumongous();
803 size_t object_num = 0;
804 while (p < top()) {
805 size_t size = oop(p)->size();
806 if (is_humongous != g1->isHumongous(size)) {
807 gclog_or_tty->print_cr("obj "PTR_FORMAT" is of %shumongous size ("
808 SIZE_FORMAT" words) in a %shumongous region",
809 p, g1->isHumongous(size) ? "" : "non-",
810 size, is_humongous ? "" : "non-");
811 *failures = true;
812 }
813 object_num += 1;
814 if (blocks == BLOCK_SAMPLE_INTERVAL) {
815 HeapWord* res = block_start_const(p + (size/2));
816 if (p != res) {
817 gclog_or_tty->print_cr("offset computation 1 for "PTR_FORMAT" and "
818 SIZE_FORMAT" returned "PTR_FORMAT,
819 p, size, res);
820 *failures = true;
821 return;
822 }
823 blocks = 0;
824 } else {
825 blocks++;
826 }
827 if (objs == OBJ_SAMPLE_INTERVAL) {
828 oop obj = oop(p);
829 if (!g1->is_obj_dead_cond(obj, this, use_prev_marking)) {
830 if (obj->is_oop()) {
831 klassOop klass = obj->klass();
832 if (!klass->is_perm()) {
833 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
834 "not in perm", klass, obj);
835 *failures = true;
836 return;
837 } else if (!klass->is_klass()) {
838 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
839 "not a klass", klass, obj);
840 *failures = true;
841 return;
842 } else {
843 vl_cl.set_containing_obj(obj);
844 obj->oop_iterate(&vl_cl);
845 if (vl_cl.failures()) {
846 *failures = true;
847 }
848 if (G1MaxVerifyFailures >= 0 &&
849 vl_cl.n_failures() >= G1MaxVerifyFailures) {
850 return;
851 }
852 }
853 } else {
854 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", obj);
855 *failures = true;
856 return;
857 }
858 }
859 objs = 0;
860 } else {
861 objs++;
862 }
863 prev_p = p;
864 p += size;
865 }
866 HeapWord* rend = end();
867 HeapWord* rtop = top();
868 if (rtop < rend) {
869 HeapWord* res = block_start_const(rtop + (rend - rtop) / 2);
870 if (res != rtop) {
871 gclog_or_tty->print_cr("offset computation 2 for "PTR_FORMAT" and "
872 PTR_FORMAT" returned "PTR_FORMAT,
873 rtop, rend, res);
874 *failures = true;
875 return;
876 }
877 }
878
879 if (is_humongous && object_num > 1) {
880 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous "
881 "but has "SIZE_FORMAT", objects",
882 bottom(), end(), object_num);
883 *failures = true;
884 }
885
886 if (p != top()) {
887 gclog_or_tty->print_cr("end of last object "PTR_FORMAT" "
888 "does not match top "PTR_FORMAT, p, top());
889 *failures = true;
890 return;
891 }
892 }
893
894 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
895 // away eventually.
896
897 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
898 // false ==> we'll do the clearing if there's clearing to be done.
899 ContiguousSpace::initialize(mr, false, mangle_space);
900 _offsets.zero_bottom_entry();
901 _offsets.initialize_threshold();
902 if (clear_space) clear(mangle_space);
903 }
904
905 void G1OffsetTableContigSpace::clear(bool mangle_space) {
906 ContiguousSpace::clear(mangle_space);
907 _offsets.zero_bottom_entry();
908 _offsets.initialize_threshold();
909 }
910
911 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
912 Space::set_bottom(new_bottom);
913 _offsets.set_bottom(new_bottom);
914 }
915
916 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
917 Space::set_end(new_end);
918 _offsets.resize(new_end - bottom());
919 }
920
921 void G1OffsetTableContigSpace::print() const {
922 print_short();
923 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
924 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
925 bottom(), top(), _offsets.threshold(), end());
926 }
927
928 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
929 return _offsets.initialize_threshold();
930 }
931
932 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
933 HeapWord* end) {
934 _offsets.alloc_block(start, end);
935 return _offsets.threshold();
936 }
937
938 HeapWord* G1OffsetTableContigSpace::saved_mark_word() const {
939 G1CollectedHeap* g1h = G1CollectedHeap::heap();
940 assert( _gc_time_stamp <= g1h->get_gc_time_stamp(), "invariant" );
941 if (_gc_time_stamp < g1h->get_gc_time_stamp())
942 return top();
943 else
944 return ContiguousSpace::saved_mark_word();
945 }
946
947 void G1OffsetTableContigSpace::set_saved_mark() {
948 G1CollectedHeap* g1h = G1CollectedHeap::heap();
949 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
950
951 if (_gc_time_stamp < curr_gc_time_stamp) {
952 // The order of these is important, as another thread might be
953 // about to start scanning this region. If it does so after
954 // set_saved_mark and before _gc_time_stamp = ..., then the latter
955 // will be false, and it will pick up top() as the high water mark
956 // of region. If it does so after _gc_time_stamp = ..., then it
957 // will pick up the right saved_mark_word() as the high water mark
958 // of the region. Either way, the behaviour will be correct.
959 ContiguousSpace::set_saved_mark();
960 OrderAccess::storestore();
961 _gc_time_stamp = curr_gc_time_stamp;
962 // The following fence is to force a flush of the writes above, but
963 // is strictly not needed because when an allocating worker thread
964 // calls set_saved_mark() it does so under the ParGCRareEvent_lock;
965 // when the lock is released, the write will be flushed.
966 // OrderAccess::fence();
967 }
968 }
969
970 G1OffsetTableContigSpace::
971 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
972 MemRegion mr, bool is_zeroed) :
973 _offsets(sharedOffsetArray, mr),
974 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
975 _gc_time_stamp(0)
976 {
977 _offsets.set_space(this);
978 initialize(mr, !is_zeroed, SpaceDecorator::Mangle);
979 }
980
981 size_t RegionList::length() {
982 size_t len = 0;
983 HeapRegion* cur = hd();
984 DEBUG_ONLY(HeapRegion* last = NULL);
985 while (cur != NULL) {
986 len++;
987 DEBUG_ONLY(last = cur);
988 cur = get_next(cur);
989 }
990 assert(last == tl(), "Invariant");
991 return len;
992 }
993
994 void RegionList::insert_before_head(HeapRegion* r) {
995 assert(well_formed(), "Inv");
996 set_next(r, hd());
997 _hd = r;
998 _sz++;
999 if (tl() == NULL) _tl = r;
1000 assert(well_formed(), "Inv");
1001 }
1002
1003 void RegionList::prepend_list(RegionList* new_list) {
1004 assert(well_formed(), "Precondition");
1005 assert(new_list->well_formed(), "Precondition");
1006 HeapRegion* new_tl = new_list->tl();
1007 if (new_tl != NULL) {
1008 set_next(new_tl, hd());
1009 _hd = new_list->hd();
1010 _sz += new_list->sz();
1011 if (tl() == NULL) _tl = new_list->tl();
1012 } else {
1013 assert(new_list->hd() == NULL && new_list->sz() == 0, "Inv");
1014 }
1015 assert(well_formed(), "Inv");
1016 }
1017
1018 void RegionList::delete_after(HeapRegion* r) {
1019 assert(well_formed(), "Precondition");
1020 HeapRegion* next = get_next(r);
1021 assert(r != NULL, "Precondition");
1022 HeapRegion* next_tl = get_next(next);
1023 set_next(r, next_tl);
1024 dec_sz();
1025 if (next == tl()) {
1026 assert(next_tl == NULL, "Inv");
1027 _tl = r;
1028 }
1029 assert(well_formed(), "Inv");
1030 }
1031
1032 HeapRegion* RegionList::pop() {
1033 assert(well_formed(), "Inv");
1034 HeapRegion* res = hd();
1035 if (res != NULL) {
1036 _hd = get_next(res);
1037 _sz--;
1038 set_next(res, NULL);
1039 if (sz() == 0) _tl = NULL;
1040 }
1041 assert(well_formed(), "Inv");
1042 return res;
1043 }