Tue, 26 Jan 2010 16:52:29 -0800
6920090: G1: Disable ReduceInitialCardMarks at least until 6920109 is fixed
Summary: G1 now answers "no" to the query can_elide_initializing_store_barrier() in the product build. A debug flag allows alternate behaviour in debug builds.
Reviewed-by: iveresov, tonyp
1 /*
2 * Copyright 2001-2009 Sun Microsystems, Inc. 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 Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
20 * CA 95054 USA or visit www.sun.com if you need additional information or
21 * have any questions.
22 *
23 */
25 #include "incls/_precompiled.incl"
26 #include "incls/_heapRegion.cpp.incl"
28 int HeapRegion::LogOfHRGrainBytes = 0;
29 int HeapRegion::LogOfHRGrainWords = 0;
30 int HeapRegion::GrainBytes = 0;
31 int HeapRegion::GrainWords = 0;
32 int HeapRegion::CardsPerRegion = 0;
34 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
35 HeapRegion* hr, OopClosure* cl,
36 CardTableModRefBS::PrecisionStyle precision,
37 FilterKind fk) :
38 ContiguousSpaceDCTOC(hr, cl, precision, NULL),
39 _hr(hr), _fk(fk), _g1(g1)
40 {}
42 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
43 OopClosure* oc) :
44 _r_bottom(r->bottom()), _r_end(r->end()),
45 _oc(oc), _out_of_region(0)
46 {}
48 class VerifyLiveClosure: public OopClosure {
49 private:
50 G1CollectedHeap* _g1h;
51 CardTableModRefBS* _bs;
52 oop _containing_obj;
53 bool _failures;
54 int _n_failures;
55 bool _use_prev_marking;
56 public:
57 // use_prev_marking == true -> use "prev" marking information,
58 // use_prev_marking == false -> use "next" marking information
59 VerifyLiveClosure(G1CollectedHeap* g1h, bool use_prev_marking) :
60 _g1h(g1h), _bs(NULL), _containing_obj(NULL),
61 _failures(false), _n_failures(0), _use_prev_marking(use_prev_marking)
62 {
63 BarrierSet* bs = _g1h->barrier_set();
64 if (bs->is_a(BarrierSet::CardTableModRef))
65 _bs = (CardTableModRefBS*)bs;
66 }
68 void set_containing_obj(oop obj) {
69 _containing_obj = obj;
70 }
72 bool failures() { return _failures; }
73 int n_failures() { return _n_failures; }
75 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
76 virtual void do_oop( oop* p) { do_oop_work(p); }
78 template <class T> void do_oop_work(T* p) {
79 assert(_containing_obj != NULL, "Precondition");
80 assert(!_g1h->is_obj_dead_cond(_containing_obj, _use_prev_marking),
81 "Precondition");
82 T heap_oop = oopDesc::load_heap_oop(p);
83 if (!oopDesc::is_null(heap_oop)) {
84 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
85 bool failed = false;
86 if (!_g1h->is_in_closed_subset(obj) ||
87 _g1h->is_obj_dead_cond(obj, _use_prev_marking)) {
88 if (!_failures) {
89 gclog_or_tty->print_cr("");
90 gclog_or_tty->print_cr("----------");
91 }
92 if (!_g1h->is_in_closed_subset(obj)) {
93 gclog_or_tty->print_cr("Field "PTR_FORMAT
94 " of live obj "PTR_FORMAT
95 " points to obj "PTR_FORMAT
96 " not in the heap.",
97 p, (void*) _containing_obj, (void*) obj);
98 } else {
99 gclog_or_tty->print_cr("Field "PTR_FORMAT
100 " of live obj "PTR_FORMAT
101 " points to dead obj "PTR_FORMAT".",
102 p, (void*) _containing_obj, (void*) obj);
103 }
104 gclog_or_tty->print_cr("Live obj:");
105 _containing_obj->print_on(gclog_or_tty);
106 gclog_or_tty->print_cr("Bad referent:");
107 obj->print_on(gclog_or_tty);
108 gclog_or_tty->print_cr("----------");
109 _failures = true;
110 failed = true;
111 _n_failures++;
112 }
114 if (!_g1h->full_collection()) {
115 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
116 HeapRegion* to = _g1h->heap_region_containing(obj);
117 if (from != NULL && to != NULL &&
118 from != to &&
119 !to->isHumongous()) {
120 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
121 jbyte cv_field = *_bs->byte_for_const(p);
122 const jbyte dirty = CardTableModRefBS::dirty_card_val();
124 bool is_bad = !(from->is_young()
125 || to->rem_set()->contains_reference(p)
126 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
127 (_containing_obj->is_objArray() ?
128 cv_field == dirty
129 : cv_obj == dirty || cv_field == dirty));
130 if (is_bad) {
131 if (!_failures) {
132 gclog_or_tty->print_cr("");
133 gclog_or_tty->print_cr("----------");
134 }
135 gclog_or_tty->print_cr("Missing rem set entry:");
136 gclog_or_tty->print_cr("Field "PTR_FORMAT
137 " of obj "PTR_FORMAT
138 ", in region %d ["PTR_FORMAT
139 ", "PTR_FORMAT"),",
140 p, (void*) _containing_obj,
141 from->hrs_index(),
142 from->bottom(),
143 from->end());
144 _containing_obj->print_on(gclog_or_tty);
145 gclog_or_tty->print_cr("points to obj "PTR_FORMAT
146 " in region %d ["PTR_FORMAT
147 ", "PTR_FORMAT").",
148 (void*) obj, to->hrs_index(),
149 to->bottom(), to->end());
150 obj->print_on(gclog_or_tty);
151 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
152 cv_obj, cv_field);
153 gclog_or_tty->print_cr("----------");
154 _failures = true;
155 if (!failed) _n_failures++;
156 }
157 }
158 }
159 }
160 }
161 };
163 template<class ClosureType>
164 HeapWord* walk_mem_region_loop(ClosureType* cl, G1CollectedHeap* g1h,
165 HeapRegion* hr,
166 HeapWord* cur, HeapWord* top) {
167 oop cur_oop = oop(cur);
168 int oop_size = cur_oop->size();
169 HeapWord* next_obj = cur + oop_size;
170 while (next_obj < top) {
171 // Keep filtering the remembered set.
172 if (!g1h->is_obj_dead(cur_oop, hr)) {
173 // Bottom lies entirely below top, so we can call the
174 // non-memRegion version of oop_iterate below.
175 cur_oop->oop_iterate(cl);
176 }
177 cur = next_obj;
178 cur_oop = oop(cur);
179 oop_size = cur_oop->size();
180 next_obj = cur + oop_size;
181 }
182 return cur;
183 }
185 void HeapRegionDCTOC::walk_mem_region_with_cl(MemRegion mr,
186 HeapWord* bottom,
187 HeapWord* top,
188 OopClosure* cl) {
189 G1CollectedHeap* g1h = _g1;
191 int oop_size;
193 OopClosure* cl2 = cl;
194 FilterIntoCSClosure intoCSFilt(this, g1h, cl);
195 FilterOutOfRegionClosure outOfRegionFilt(_hr, cl);
196 switch (_fk) {
197 case IntoCSFilterKind: cl2 = &intoCSFilt; break;
198 case OutOfRegionFilterKind: cl2 = &outOfRegionFilt; break;
199 }
201 // Start filtering what we add to the remembered set. If the object is
202 // not considered dead, either because it is marked (in the mark bitmap)
203 // or it was allocated after marking finished, then we add it. Otherwise
204 // we can safely ignore the object.
205 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
206 oop_size = oop(bottom)->oop_iterate(cl2, mr);
207 } else {
208 oop_size = oop(bottom)->size();
209 }
211 bottom += oop_size;
213 if (bottom < top) {
214 // We replicate the loop below for several kinds of possible filters.
215 switch (_fk) {
216 case NoFilterKind:
217 bottom = walk_mem_region_loop(cl, g1h, _hr, bottom, top);
218 break;
219 case IntoCSFilterKind: {
220 FilterIntoCSClosure filt(this, g1h, cl);
221 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
222 break;
223 }
224 case OutOfRegionFilterKind: {
225 FilterOutOfRegionClosure filt(_hr, cl);
226 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
227 break;
228 }
229 default:
230 ShouldNotReachHere();
231 }
233 // Last object. Need to do dead-obj filtering here too.
234 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
235 oop(bottom)->oop_iterate(cl2, mr);
236 }
237 }
238 }
240 // Minimum region size; we won't go lower than that.
241 // We might want to decrease this in the future, to deal with small
242 // heaps a bit more efficiently.
243 #define MIN_REGION_SIZE ( 1024 * 1024 )
245 // Maximum region size; we don't go higher than that. There's a good
246 // reason for having an upper bound. We don't want regions to get too
247 // large, otherwise cleanup's effectiveness would decrease as there
248 // will be fewer opportunities to find totally empty regions after
249 // marking.
250 #define MAX_REGION_SIZE ( 32 * 1024 * 1024 )
252 // The automatic region size calculation will try to have around this
253 // many regions in the heap (based on the min heap size).
254 #define TARGET_REGION_NUMBER 2048
256 void HeapRegion::setup_heap_region_size(uintx min_heap_size) {
257 // region_size in bytes
258 uintx region_size = G1HeapRegionSize;
259 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
260 // We base the automatic calculation on the min heap size. This
261 // can be problematic if the spread between min and max is quite
262 // wide, imagine -Xms128m -Xmx32g. But, if we decided it based on
263 // the max size, the region size might be way too large for the
264 // min size. Either way, some users might have to set the region
265 // size manually for some -Xms / -Xmx combos.
267 region_size = MAX2(min_heap_size / TARGET_REGION_NUMBER,
268 (uintx) MIN_REGION_SIZE);
269 }
271 int region_size_log = log2_long((jlong) region_size);
272 // Recalculate the region size to make sure it's a power of
273 // 2. This means that region_size is the largest power of 2 that's
274 // <= what we've calculated so far.
275 region_size = 1 << region_size_log;
277 // Now make sure that we don't go over or under our limits.
278 if (region_size < MIN_REGION_SIZE) {
279 region_size = MIN_REGION_SIZE;
280 } else if (region_size > MAX_REGION_SIZE) {
281 region_size = MAX_REGION_SIZE;
282 }
284 // And recalculate the log.
285 region_size_log = log2_long((jlong) region_size);
287 // Now, set up the globals.
288 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
289 LogOfHRGrainBytes = region_size_log;
291 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
292 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
294 guarantee(GrainBytes == 0, "we should only set it once");
295 // The cast to int is safe, given that we've bounded region_size by
296 // MIN_REGION_SIZE and MAX_REGION_SIZE.
297 GrainBytes = (int) region_size;
299 guarantee(GrainWords == 0, "we should only set it once");
300 GrainWords = GrainBytes >> LogHeapWordSize;
301 guarantee(1 << LogOfHRGrainWords == GrainWords, "sanity");
303 guarantee(CardsPerRegion == 0, "we should only set it once");
304 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
305 }
307 void HeapRegion::reset_after_compaction() {
308 G1OffsetTableContigSpace::reset_after_compaction();
309 // After a compaction the mark bitmap is invalid, so we must
310 // treat all objects as being inside the unmarked area.
311 zero_marked_bytes();
312 init_top_at_mark_start();
313 }
315 DirtyCardToOopClosure*
316 HeapRegion::new_dcto_closure(OopClosure* cl,
317 CardTableModRefBS::PrecisionStyle precision,
318 HeapRegionDCTOC::FilterKind fk) {
319 return new HeapRegionDCTOC(G1CollectedHeap::heap(),
320 this, cl, precision, fk);
321 }
323 void HeapRegion::hr_clear(bool par, bool clear_space) {
324 _humongous_type = NotHumongous;
325 _humongous_start_region = NULL;
326 _in_collection_set = false;
327 _is_gc_alloc_region = false;
329 // Age stuff (if parallel, this will be done separately, since it needs
330 // to be sequential).
331 G1CollectedHeap* g1h = G1CollectedHeap::heap();
333 set_young_index_in_cset(-1);
334 uninstall_surv_rate_group();
335 set_young_type(NotYoung);
337 // In case it had been the start of a humongous sequence, reset its end.
338 set_end(_orig_end);
340 if (!par) {
341 // If this is parallel, this will be done later.
342 HeapRegionRemSet* hrrs = rem_set();
343 if (hrrs != NULL) hrrs->clear();
344 _claimed = InitialClaimValue;
345 }
346 zero_marked_bytes();
347 set_sort_index(-1);
349 _offsets.resize(HeapRegion::GrainWords);
350 init_top_at_mark_start();
351 if (clear_space) clear(SpaceDecorator::Mangle);
352 }
354 // <PREDICTION>
355 void HeapRegion::calc_gc_efficiency() {
356 G1CollectedHeap* g1h = G1CollectedHeap::heap();
357 _gc_efficiency = (double) garbage_bytes() /
358 g1h->predict_region_elapsed_time_ms(this, false);
359 }
360 // </PREDICTION>
362 void HeapRegion::set_startsHumongous() {
363 _humongous_type = StartsHumongous;
364 _humongous_start_region = this;
365 assert(end() == _orig_end, "Should be normal before alloc.");
366 }
368 bool HeapRegion::claimHeapRegion(jint claimValue) {
369 jint current = _claimed;
370 if (current != claimValue) {
371 jint res = Atomic::cmpxchg(claimValue, &_claimed, current);
372 if (res == current) {
373 return true;
374 }
375 }
376 return false;
377 }
379 HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) {
380 HeapWord* low = addr;
381 HeapWord* high = end();
382 while (low < high) {
383 size_t diff = pointer_delta(high, low);
384 // Must add one below to bias toward the high amount. Otherwise, if
385 // "high" were at the desired value, and "low" were one less, we
386 // would not converge on "high". This is not symmetric, because
387 // we set "high" to a block start, which might be the right one,
388 // which we don't do for "low".
389 HeapWord* middle = low + (diff+1)/2;
390 if (middle == high) return high;
391 HeapWord* mid_bs = block_start_careful(middle);
392 if (mid_bs < addr) {
393 low = middle;
394 } else {
395 high = mid_bs;
396 }
397 }
398 assert(low == high && low >= addr, "Didn't work.");
399 return low;
400 }
402 void HeapRegion::set_next_on_unclean_list(HeapRegion* r) {
403 assert(r == NULL || r->is_on_unclean_list(), "Malformed unclean list.");
404 _next_in_special_set = r;
405 }
407 void HeapRegion::set_on_unclean_list(bool b) {
408 _is_on_unclean_list = b;
409 }
411 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
412 G1OffsetTableContigSpace::initialize(mr, false, mangle_space);
413 hr_clear(false/*par*/, clear_space);
414 }
415 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
416 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
417 #endif // _MSC_VER
420 HeapRegion::
421 HeapRegion(G1BlockOffsetSharedArray* sharedOffsetArray,
422 MemRegion mr, bool is_zeroed)
423 : G1OffsetTableContigSpace(sharedOffsetArray, mr, is_zeroed),
424 _next_fk(HeapRegionDCTOC::NoFilterKind),
425 _hrs_index(-1),
426 _humongous_type(NotHumongous), _humongous_start_region(NULL),
427 _in_collection_set(false), _is_gc_alloc_region(false),
428 _is_on_free_list(false), _is_on_unclean_list(false),
429 _next_in_special_set(NULL), _orig_end(NULL),
430 _claimed(InitialClaimValue), _evacuation_failed(false),
431 _prev_marked_bytes(0), _next_marked_bytes(0), _sort_index(-1),
432 _young_type(NotYoung), _next_young_region(NULL),
433 _next_dirty_cards_region(NULL),
434 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
435 _rem_set(NULL), _zfs(NotZeroFilled)
436 {
437 _orig_end = mr.end();
438 // Note that initialize() will set the start of the unmarked area of the
439 // region.
440 this->initialize(mr, !is_zeroed, SpaceDecorator::Mangle);
441 set_top(bottom());
442 set_saved_mark();
444 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
446 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
447 // In case the region is allocated during a pause, note the top.
448 // We haven't done any counting on a brand new region.
449 _top_at_conc_mark_count = bottom();
450 }
452 class NextCompactionHeapRegionClosure: public HeapRegionClosure {
453 const HeapRegion* _target;
454 bool _target_seen;
455 HeapRegion* _last;
456 CompactibleSpace* _res;
457 public:
458 NextCompactionHeapRegionClosure(const HeapRegion* target) :
459 _target(target), _target_seen(false), _res(NULL) {}
460 bool doHeapRegion(HeapRegion* cur) {
461 if (_target_seen) {
462 if (!cur->isHumongous()) {
463 _res = cur;
464 return true;
465 }
466 } else if (cur == _target) {
467 _target_seen = true;
468 }
469 return false;
470 }
471 CompactibleSpace* result() { return _res; }
472 };
474 CompactibleSpace* HeapRegion::next_compaction_space() const {
475 G1CollectedHeap* g1h = G1CollectedHeap::heap();
476 // cast away const-ness
477 HeapRegion* r = (HeapRegion*) this;
478 NextCompactionHeapRegionClosure blk(r);
479 g1h->heap_region_iterate_from(r, &blk);
480 return blk.result();
481 }
483 void HeapRegion::set_continuesHumongous(HeapRegion* start) {
484 // The order is important here.
485 start->add_continuingHumongousRegion(this);
486 _humongous_type = ContinuesHumongous;
487 _humongous_start_region = start;
488 }
490 void HeapRegion::add_continuingHumongousRegion(HeapRegion* cont) {
491 // Must join the blocks of the current H region seq with the block of the
492 // added region.
493 offsets()->join_blocks(bottom(), cont->bottom());
494 arrayOop obj = (arrayOop)(bottom());
495 obj->set_length((int) (obj->length() + cont->capacity()/jintSize));
496 set_end(cont->end());
497 set_top(cont->end());
498 }
500 void HeapRegion::save_marks() {
501 set_saved_mark();
502 }
504 void HeapRegion::oops_in_mr_iterate(MemRegion mr, OopClosure* cl) {
505 HeapWord* p = mr.start();
506 HeapWord* e = mr.end();
507 oop obj;
508 while (p < e) {
509 obj = oop(p);
510 p += obj->oop_iterate(cl);
511 }
512 assert(p == e, "bad memregion: doesn't end on obj boundary");
513 }
515 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \
516 void HeapRegion::oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \
517 ContiguousSpace::oop_since_save_marks_iterate##nv_suffix(cl); \
518 }
519 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN)
522 void HeapRegion::oop_before_save_marks_iterate(OopClosure* cl) {
523 oops_in_mr_iterate(MemRegion(bottom(), saved_mark_word()), cl);
524 }
526 #ifdef DEBUG
527 HeapWord* HeapRegion::allocate(size_t size) {
528 jint state = zero_fill_state();
529 assert(!G1CollectedHeap::heap()->allocs_are_zero_filled() ||
530 zero_fill_is_allocated(),
531 "When ZF is on, only alloc in ZF'd regions");
532 return G1OffsetTableContigSpace::allocate(size);
533 }
534 #endif
536 void HeapRegion::set_zero_fill_state_work(ZeroFillState zfs) {
537 assert(top() == bottom() || zfs == Allocated,
538 "Region must be empty, or we must be setting it to allocated.");
539 assert(ZF_mon->owned_by_self() ||
540 Universe::heap()->is_gc_active(),
541 "Must hold the lock or be a full GC to modify.");
542 _zfs = zfs;
543 }
545 void HeapRegion::set_zero_fill_complete() {
546 set_zero_fill_state_work(ZeroFilled);
547 if (ZF_mon->owned_by_self()) {
548 ZF_mon->notify_all();
549 }
550 }
553 void HeapRegion::ensure_zero_filled() {
554 MutexLockerEx x(ZF_mon, Mutex::_no_safepoint_check_flag);
555 ensure_zero_filled_locked();
556 }
558 void HeapRegion::ensure_zero_filled_locked() {
559 assert(ZF_mon->owned_by_self(), "Precondition");
560 bool should_ignore_zf = SafepointSynchronize::is_at_safepoint();
561 assert(should_ignore_zf || Heap_lock->is_locked(),
562 "Either we're in a GC or we're allocating a region.");
563 switch (zero_fill_state()) {
564 case HeapRegion::NotZeroFilled:
565 set_zero_fill_in_progress(Thread::current());
566 {
567 ZF_mon->unlock();
568 Copy::fill_to_words(bottom(), capacity()/HeapWordSize);
569 ZF_mon->lock_without_safepoint_check();
570 }
571 // A trap.
572 guarantee(zero_fill_state() == HeapRegion::ZeroFilling
573 && zero_filler() == Thread::current(),
574 "AHA! Tell Dave D if you see this...");
575 set_zero_fill_complete();
576 // gclog_or_tty->print_cr("Did sync ZF.");
577 ConcurrentZFThread::note_sync_zfs();
578 break;
579 case HeapRegion::ZeroFilling:
580 if (should_ignore_zf) {
581 // We can "break" the lock and take over the work.
582 Copy::fill_to_words(bottom(), capacity()/HeapWordSize);
583 set_zero_fill_complete();
584 ConcurrentZFThread::note_sync_zfs();
585 break;
586 } else {
587 ConcurrentZFThread::wait_for_ZF_completed(this);
588 }
589 case HeapRegion::ZeroFilled:
590 // Nothing to do.
591 break;
592 case HeapRegion::Allocated:
593 guarantee(false, "Should not call on allocated regions.");
594 }
595 assert(zero_fill_state() == HeapRegion::ZeroFilled, "Post");
596 }
598 HeapWord*
599 HeapRegion::object_iterate_mem_careful(MemRegion mr,
600 ObjectClosure* cl) {
601 G1CollectedHeap* g1h = G1CollectedHeap::heap();
602 // We used to use "block_start_careful" here. But we're actually happy
603 // to update the BOT while we do this...
604 HeapWord* cur = block_start(mr.start());
605 mr = mr.intersection(used_region());
606 if (mr.is_empty()) return NULL;
607 // Otherwise, find the obj that extends onto mr.start().
609 assert(cur <= mr.start()
610 && (oop(cur)->klass_or_null() == NULL ||
611 cur + oop(cur)->size() > mr.start()),
612 "postcondition of block_start");
613 oop obj;
614 while (cur < mr.end()) {
615 obj = oop(cur);
616 if (obj->klass_or_null() == NULL) {
617 // Ran into an unparseable point.
618 return cur;
619 } else if (!g1h->is_obj_dead(obj)) {
620 cl->do_object(obj);
621 }
622 if (cl->abort()) return cur;
623 // The check above must occur before the operation below, since an
624 // abort might invalidate the "size" operation.
625 cur += obj->size();
626 }
627 return NULL;
628 }
630 HeapWord*
631 HeapRegion::
632 oops_on_card_seq_iterate_careful(MemRegion mr,
633 FilterOutOfRegionClosure* cl) {
634 G1CollectedHeap* g1h = G1CollectedHeap::heap();
636 // If we're within a stop-world GC, then we might look at a card in a
637 // GC alloc region that extends onto a GC LAB, which may not be
638 // parseable. Stop such at the "saved_mark" of the region.
639 if (G1CollectedHeap::heap()->is_gc_active()) {
640 mr = mr.intersection(used_region_at_save_marks());
641 } else {
642 mr = mr.intersection(used_region());
643 }
644 if (mr.is_empty()) return NULL;
645 // Otherwise, find the obj that extends onto mr.start().
647 // We used to use "block_start_careful" here. But we're actually happy
648 // to update the BOT while we do this...
649 HeapWord* cur = block_start(mr.start());
650 assert(cur <= mr.start(), "Postcondition");
652 while (cur <= mr.start()) {
653 if (oop(cur)->klass_or_null() == NULL) {
654 // Ran into an unparseable point.
655 return cur;
656 }
657 // Otherwise...
658 int sz = oop(cur)->size();
659 if (cur + sz > mr.start()) break;
660 // Otherwise, go on.
661 cur = cur + sz;
662 }
663 oop obj;
664 obj = oop(cur);
665 // If we finish this loop...
666 assert(cur <= mr.start()
667 && obj->klass_or_null() != NULL
668 && cur + obj->size() > mr.start(),
669 "Loop postcondition");
670 if (!g1h->is_obj_dead(obj)) {
671 obj->oop_iterate(cl, mr);
672 }
674 HeapWord* next;
675 while (cur < mr.end()) {
676 obj = oop(cur);
677 if (obj->klass_or_null() == NULL) {
678 // Ran into an unparseable point.
679 return cur;
680 };
681 // Otherwise:
682 next = (cur + obj->size());
683 if (!g1h->is_obj_dead(obj)) {
684 if (next < mr.end()) {
685 obj->oop_iterate(cl);
686 } else {
687 // this obj spans the boundary. If it's an array, stop at the
688 // boundary.
689 if (obj->is_objArray()) {
690 obj->oop_iterate(cl, mr);
691 } else {
692 obj->oop_iterate(cl);
693 }
694 }
695 }
696 cur = next;
697 }
698 return NULL;
699 }
701 void HeapRegion::print() const { print_on(gclog_or_tty); }
702 void HeapRegion::print_on(outputStream* st) const {
703 if (isHumongous()) {
704 if (startsHumongous())
705 st->print(" HS");
706 else
707 st->print(" HC");
708 } else {
709 st->print(" ");
710 }
711 if (in_collection_set())
712 st->print(" CS");
713 else if (is_gc_alloc_region())
714 st->print(" A ");
715 else
716 st->print(" ");
717 if (is_young())
718 st->print(is_scan_only() ? " SO" : (is_survivor() ? " SU" : " Y "));
719 else
720 st->print(" ");
721 if (is_empty())
722 st->print(" F");
723 else
724 st->print(" ");
725 st->print(" %5d", _gc_time_stamp);
726 G1OffsetTableContigSpace::print_on(st);
727 }
729 void HeapRegion::verify(bool allow_dirty) const {
730 bool dummy = false;
731 verify(allow_dirty, /* use_prev_marking */ true, /* failures */ &dummy);
732 }
734 #define OBJ_SAMPLE_INTERVAL 0
735 #define BLOCK_SAMPLE_INTERVAL 100
737 // This really ought to be commoned up into OffsetTableContigSpace somehow.
738 // We would need a mechanism to make that code skip dead objects.
740 void HeapRegion::verify(bool allow_dirty,
741 bool use_prev_marking,
742 bool* failures) const {
743 G1CollectedHeap* g1 = G1CollectedHeap::heap();
744 *failures = false;
745 HeapWord* p = bottom();
746 HeapWord* prev_p = NULL;
747 int objs = 0;
748 int blocks = 0;
749 VerifyLiveClosure vl_cl(g1, use_prev_marking);
750 while (p < top()) {
751 size_t size = oop(p)->size();
752 if (blocks == BLOCK_SAMPLE_INTERVAL) {
753 HeapWord* res = block_start_const(p + (size/2));
754 if (p != res) {
755 gclog_or_tty->print_cr("offset computation 1 for "PTR_FORMAT" and "
756 SIZE_FORMAT" returned "PTR_FORMAT,
757 p, size, res);
758 *failures = true;
759 return;
760 }
761 blocks = 0;
762 } else {
763 blocks++;
764 }
765 if (objs == OBJ_SAMPLE_INTERVAL) {
766 oop obj = oop(p);
767 if (!g1->is_obj_dead_cond(obj, this, use_prev_marking)) {
768 if (obj->is_oop()) {
769 klassOop klass = obj->klass();
770 if (!klass->is_perm()) {
771 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
772 "not in perm", klass, obj);
773 *failures = true;
774 return;
775 } else if (!klass->is_klass()) {
776 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
777 "not a klass", klass, obj);
778 *failures = true;
779 return;
780 } else {
781 vl_cl.set_containing_obj(obj);
782 obj->oop_iterate(&vl_cl);
783 if (vl_cl.failures()) {
784 *failures = true;
785 }
786 if (G1MaxVerifyFailures >= 0 &&
787 vl_cl.n_failures() >= G1MaxVerifyFailures) {
788 return;
789 }
790 }
791 } else {
792 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", obj);
793 *failures = true;
794 return;
795 }
796 }
797 objs = 0;
798 } else {
799 objs++;
800 }
801 prev_p = p;
802 p += size;
803 }
804 HeapWord* rend = end();
805 HeapWord* rtop = top();
806 if (rtop < rend) {
807 HeapWord* res = block_start_const(rtop + (rend - rtop) / 2);
808 if (res != rtop) {
809 gclog_or_tty->print_cr("offset computation 2 for "PTR_FORMAT" and "
810 PTR_FORMAT" returned "PTR_FORMAT,
811 rtop, rend, res);
812 *failures = true;
813 return;
814 }
815 }
817 if (p != top()) {
818 gclog_or_tty->print_cr("end of last object "PTR_FORMAT" "
819 "does not match top "PTR_FORMAT, p, top());
820 *failures = true;
821 return;
822 }
823 }
825 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
826 // away eventually.
828 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
829 // false ==> we'll do the clearing if there's clearing to be done.
830 ContiguousSpace::initialize(mr, false, mangle_space);
831 _offsets.zero_bottom_entry();
832 _offsets.initialize_threshold();
833 if (clear_space) clear(mangle_space);
834 }
836 void G1OffsetTableContigSpace::clear(bool mangle_space) {
837 ContiguousSpace::clear(mangle_space);
838 _offsets.zero_bottom_entry();
839 _offsets.initialize_threshold();
840 }
842 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
843 Space::set_bottom(new_bottom);
844 _offsets.set_bottom(new_bottom);
845 }
847 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
848 Space::set_end(new_end);
849 _offsets.resize(new_end - bottom());
850 }
852 void G1OffsetTableContigSpace::print() const {
853 print_short();
854 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
855 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
856 bottom(), top(), _offsets.threshold(), end());
857 }
859 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
860 return _offsets.initialize_threshold();
861 }
863 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
864 HeapWord* end) {
865 _offsets.alloc_block(start, end);
866 return _offsets.threshold();
867 }
869 HeapWord* G1OffsetTableContigSpace::saved_mark_word() const {
870 G1CollectedHeap* g1h = G1CollectedHeap::heap();
871 assert( _gc_time_stamp <= g1h->get_gc_time_stamp(), "invariant" );
872 if (_gc_time_stamp < g1h->get_gc_time_stamp())
873 return top();
874 else
875 return ContiguousSpace::saved_mark_word();
876 }
878 void G1OffsetTableContigSpace::set_saved_mark() {
879 G1CollectedHeap* g1h = G1CollectedHeap::heap();
880 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
882 if (_gc_time_stamp < curr_gc_time_stamp) {
883 // The order of these is important, as another thread might be
884 // about to start scanning this region. If it does so after
885 // set_saved_mark and before _gc_time_stamp = ..., then the latter
886 // will be false, and it will pick up top() as the high water mark
887 // of region. If it does so after _gc_time_stamp = ..., then it
888 // will pick up the right saved_mark_word() as the high water mark
889 // of the region. Either way, the behaviour will be correct.
890 ContiguousSpace::set_saved_mark();
891 OrderAccess::storestore();
892 _gc_time_stamp = curr_gc_time_stamp;
893 // The following fence is to force a flush of the writes above, but
894 // is strictly not needed because when an allocating worker thread
895 // calls set_saved_mark() it does so under the ParGCRareEvent_lock;
896 // when the lock is released, the write will be flushed.
897 // OrderAccess::fence();
898 }
899 }
901 G1OffsetTableContigSpace::
902 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
903 MemRegion mr, bool is_zeroed) :
904 _offsets(sharedOffsetArray, mr),
905 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
906 _gc_time_stamp(0)
907 {
908 _offsets.set_space(this);
909 initialize(mr, !is_zeroed, SpaceDecorator::Mangle);
910 }
912 size_t RegionList::length() {
913 size_t len = 0;
914 HeapRegion* cur = hd();
915 DEBUG_ONLY(HeapRegion* last = NULL);
916 while (cur != NULL) {
917 len++;
918 DEBUG_ONLY(last = cur);
919 cur = get_next(cur);
920 }
921 assert(last == tl(), "Invariant");
922 return len;
923 }
925 void RegionList::insert_before_head(HeapRegion* r) {
926 assert(well_formed(), "Inv");
927 set_next(r, hd());
928 _hd = r;
929 _sz++;
930 if (tl() == NULL) _tl = r;
931 assert(well_formed(), "Inv");
932 }
934 void RegionList::prepend_list(RegionList* new_list) {
935 assert(well_formed(), "Precondition");
936 assert(new_list->well_formed(), "Precondition");
937 HeapRegion* new_tl = new_list->tl();
938 if (new_tl != NULL) {
939 set_next(new_tl, hd());
940 _hd = new_list->hd();
941 _sz += new_list->sz();
942 if (tl() == NULL) _tl = new_list->tl();
943 } else {
944 assert(new_list->hd() == NULL && new_list->sz() == 0, "Inv");
945 }
946 assert(well_formed(), "Inv");
947 }
949 void RegionList::delete_after(HeapRegion* r) {
950 assert(well_formed(), "Precondition");
951 HeapRegion* next = get_next(r);
952 assert(r != NULL, "Precondition");
953 HeapRegion* next_tl = get_next(next);
954 set_next(r, next_tl);
955 dec_sz();
956 if (next == tl()) {
957 assert(next_tl == NULL, "Inv");
958 _tl = r;
959 }
960 assert(well_formed(), "Inv");
961 }
963 HeapRegion* RegionList::pop() {
964 assert(well_formed(), "Inv");
965 HeapRegion* res = hd();
966 if (res != NULL) {
967 _hd = get_next(res);
968 _sz--;
969 set_next(res, NULL);
970 if (sz() == 0) _tl = NULL;
971 }
972 assert(well_formed(), "Inv");
973 return res;
974 }