Mercurial > jdk8-mips64-public > hotspot / file revision
src/share/vm/gc_implementation/g1/heapRegion.cpp@0ac769a57c64
src/share/vm/gc_implementation/g1/heapRegion.cpp
Tue, 01 Mar 2011 14:56:48 -0800
- author
- iveresov
- date
- Tue, 01 Mar 2011 14:56:48 -0800
- changeset 2606
- 0ac769a57c64
- parent 2472
- 0fa27f37d4d4
- child 2715
- abdfc822206f
- permissions
- -rw-r--r--
6627983: G1: Bad oop deference during marking
Summary: Bulk zeroing reduction didn't work with G1, because arraycopy would call pre-barriers on uninitialized oops. The solution is to have version of arraycopy stubs that don't have pre-barriers. Also refactored arraycopy stubs generation on SPARC to be more readable and reduced the number of stubs necessary in some cases.
Reviewed-by: jrose, kvn, never
1 /*
2 * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 #include "precompiled.hpp"
26 #include "gc_implementation/g1/g1BlockOffsetTable.inline.hpp"
27 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
28 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
29 #include "gc_implementation/g1/heapRegion.inline.hpp"
30 #include "gc_implementation/g1/heapRegionRemSet.hpp"
31 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
32 #include "memory/genOopClosures.inline.hpp"
33 #include "memory/iterator.hpp"
34 #include "oops/oop.inline.hpp"
36 int HeapRegion::LogOfHRGrainBytes = 0;
37 int HeapRegion::LogOfHRGrainWords = 0;
38 int HeapRegion::GrainBytes = 0;
39 int HeapRegion::GrainWords = 0;
40 int HeapRegion::CardsPerRegion = 0;
42 HeapRegionDCTOC::HeapRegionDCTOC(G1CollectedHeap* g1,
43 HeapRegion* hr, OopClosure* cl,
44 CardTableModRefBS::PrecisionStyle precision,
45 FilterKind fk) :
46 ContiguousSpaceDCTOC(hr, cl, precision, NULL),
47 _hr(hr), _fk(fk), _g1(g1)
48 {}
50 FilterOutOfRegionClosure::FilterOutOfRegionClosure(HeapRegion* r,
51 OopClosure* oc) :
52 _r_bottom(r->bottom()), _r_end(r->end()),
53 _oc(oc), _out_of_region(0)
54 {}
56 class VerifyLiveClosure: public OopClosure {
57 private:
58 G1CollectedHeap* _g1h;
59 CardTableModRefBS* _bs;
60 oop _containing_obj;
61 bool _failures;
62 int _n_failures;
63 bool _use_prev_marking;
64 public:
65 // use_prev_marking == true -> use "prev" marking information,
66 // use_prev_marking == false -> use "next" marking information
67 VerifyLiveClosure(G1CollectedHeap* g1h, bool use_prev_marking) :
68 _g1h(g1h), _bs(NULL), _containing_obj(NULL),
69 _failures(false), _n_failures(0), _use_prev_marking(use_prev_marking)
70 {
71 BarrierSet* bs = _g1h->barrier_set();
72 if (bs->is_a(BarrierSet::CardTableModRef))
73 _bs = (CardTableModRefBS*)bs;
74 }
76 void set_containing_obj(oop obj) {
77 _containing_obj = obj;
78 }
80 bool failures() { return _failures; }
81 int n_failures() { return _n_failures; }
83 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
84 virtual void do_oop( oop* p) { do_oop_work(p); }
86 void print_object(outputStream* out, oop obj) {
87 #ifdef PRODUCT
88 klassOop k = obj->klass();
89 const char* class_name = instanceKlass::cast(k)->external_name();
90 out->print_cr("class name %s", class_name);
91 #else // PRODUCT
92 obj->print_on(out);
93 #endif // PRODUCT
94 }
96 template <class T> void do_oop_work(T* p) {
97 assert(_containing_obj != NULL, "Precondition");
98 assert(!_g1h->is_obj_dead_cond(_containing_obj, _use_prev_marking),
99 "Precondition");
100 T heap_oop = oopDesc::load_heap_oop(p);
101 if (!oopDesc::is_null(heap_oop)) {
102 oop obj = oopDesc::decode_heap_oop_not_null(heap_oop);
103 bool failed = false;
104 if (!_g1h->is_in_closed_subset(obj) ||
105 _g1h->is_obj_dead_cond(obj, _use_prev_marking)) {
106 if (!_failures) {
107 gclog_or_tty->print_cr("");
108 gclog_or_tty->print_cr("----------");
109 }
110 if (!_g1h->is_in_closed_subset(obj)) {
111 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
112 gclog_or_tty->print_cr("Field "PTR_FORMAT
113 " of live obj "PTR_FORMAT" in region "
114 "["PTR_FORMAT", "PTR_FORMAT")",
115 p, (void*) _containing_obj,
116 from->bottom(), from->end());
117 print_object(gclog_or_tty, _containing_obj);
118 gclog_or_tty->print_cr("points to obj "PTR_FORMAT" not in the heap",
119 (void*) obj);
120 } else {
121 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
122 HeapRegion* to = _g1h->heap_region_containing((HeapWord*)obj);
123 gclog_or_tty->print_cr("Field "PTR_FORMAT
124 " of live obj "PTR_FORMAT" in region "
125 "["PTR_FORMAT", "PTR_FORMAT")",
126 p, (void*) _containing_obj,
127 from->bottom(), from->end());
128 print_object(gclog_or_tty, _containing_obj);
129 gclog_or_tty->print_cr("points to dead obj "PTR_FORMAT" in region "
130 "["PTR_FORMAT", "PTR_FORMAT")",
131 (void*) obj, to->bottom(), to->end());
132 print_object(gclog_or_tty, obj);
133 }
134 gclog_or_tty->print_cr("----------");
135 _failures = true;
136 failed = true;
137 _n_failures++;
138 }
140 if (!_g1h->full_collection()) {
141 HeapRegion* from = _g1h->heap_region_containing((HeapWord*)p);
142 HeapRegion* to = _g1h->heap_region_containing(obj);
143 if (from != NULL && to != NULL &&
144 from != to &&
145 !to->isHumongous()) {
146 jbyte cv_obj = *_bs->byte_for_const(_containing_obj);
147 jbyte cv_field = *_bs->byte_for_const(p);
148 const jbyte dirty = CardTableModRefBS::dirty_card_val();
150 bool is_bad = !(from->is_young()
151 || to->rem_set()->contains_reference(p)
152 || !G1HRRSFlushLogBuffersOnVerify && // buffers were not flushed
153 (_containing_obj->is_objArray() ?
154 cv_field == dirty
155 : cv_obj == dirty || cv_field == dirty));
156 if (is_bad) {
157 if (!_failures) {
158 gclog_or_tty->print_cr("");
159 gclog_or_tty->print_cr("----------");
160 }
161 gclog_or_tty->print_cr("Missing rem set entry:");
162 gclog_or_tty->print_cr("Field "PTR_FORMAT
163 " of obj "PTR_FORMAT
164 ", in region %d ["PTR_FORMAT
165 ", "PTR_FORMAT"),",
166 p, (void*) _containing_obj,
167 from->hrs_index(),
168 from->bottom(),
169 from->end());
170 _containing_obj->print_on(gclog_or_tty);
171 gclog_or_tty->print_cr("points to obj "PTR_FORMAT
172 " in region %d ["PTR_FORMAT
173 ", "PTR_FORMAT").",
174 (void*) obj, to->hrs_index(),
175 to->bottom(), to->end());
176 obj->print_on(gclog_or_tty);
177 gclog_or_tty->print_cr("Obj head CTE = %d, field CTE = %d.",
178 cv_obj, cv_field);
179 gclog_or_tty->print_cr("----------");
180 _failures = true;
181 if (!failed) _n_failures++;
182 }
183 }
184 }
185 }
186 }
187 };
189 template<class ClosureType>
190 HeapWord* walk_mem_region_loop(ClosureType* cl, G1CollectedHeap* g1h,
191 HeapRegion* hr,
192 HeapWord* cur, HeapWord* top) {
193 oop cur_oop = oop(cur);
194 int oop_size = cur_oop->size();
195 HeapWord* next_obj = cur + oop_size;
196 while (next_obj < top) {
197 // Keep filtering the remembered set.
198 if (!g1h->is_obj_dead(cur_oop, hr)) {
199 // Bottom lies entirely below top, so we can call the
200 // non-memRegion version of oop_iterate below.
201 cur_oop->oop_iterate(cl);
202 }
203 cur = next_obj;
204 cur_oop = oop(cur);
205 oop_size = cur_oop->size();
206 next_obj = cur + oop_size;
207 }
208 return cur;
209 }
211 void HeapRegionDCTOC::walk_mem_region_with_cl(MemRegion mr,
212 HeapWord* bottom,
213 HeapWord* top,
214 OopClosure* cl) {
215 G1CollectedHeap* g1h = _g1;
217 int oop_size;
219 OopClosure* cl2 = cl;
220 FilterIntoCSClosure intoCSFilt(this, g1h, cl);
221 FilterOutOfRegionClosure outOfRegionFilt(_hr, cl);
222 switch (_fk) {
223 case IntoCSFilterKind: cl2 = &intoCSFilt; break;
224 case OutOfRegionFilterKind: cl2 = &outOfRegionFilt; break;
225 }
227 // Start filtering what we add to the remembered set. If the object is
228 // not considered dead, either because it is marked (in the mark bitmap)
229 // or it was allocated after marking finished, then we add it. Otherwise
230 // we can safely ignore the object.
231 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
232 oop_size = oop(bottom)->oop_iterate(cl2, mr);
233 } else {
234 oop_size = oop(bottom)->size();
235 }
237 bottom += oop_size;
239 if (bottom < top) {
240 // We replicate the loop below for several kinds of possible filters.
241 switch (_fk) {
242 case NoFilterKind:
243 bottom = walk_mem_region_loop(cl, g1h, _hr, bottom, top);
244 break;
245 case IntoCSFilterKind: {
246 FilterIntoCSClosure filt(this, g1h, cl);
247 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
248 break;
249 }
250 case OutOfRegionFilterKind: {
251 FilterOutOfRegionClosure filt(_hr, cl);
252 bottom = walk_mem_region_loop(&filt, g1h, _hr, bottom, top);
253 break;
254 }
255 default:
256 ShouldNotReachHere();
257 }
259 // Last object. Need to do dead-obj filtering here too.
260 if (!g1h->is_obj_dead(oop(bottom), _hr)) {
261 oop(bottom)->oop_iterate(cl2, mr);
262 }
263 }
264 }
266 // Minimum region size; we won't go lower than that.
267 // We might want to decrease this in the future, to deal with small
268 // heaps a bit more efficiently.
269 #define MIN_REGION_SIZE ( 1024 * 1024 )
271 // Maximum region size; we don't go higher than that. There's a good
272 // reason for having an upper bound. We don't want regions to get too
273 // large, otherwise cleanup's effectiveness would decrease as there
274 // will be fewer opportunities to find totally empty regions after
275 // marking.
276 #define MAX_REGION_SIZE ( 32 * 1024 * 1024 )
278 // The automatic region size calculation will try to have around this
279 // many regions in the heap (based on the min heap size).
280 #define TARGET_REGION_NUMBER 2048
282 void HeapRegion::setup_heap_region_size(uintx min_heap_size) {
283 // region_size in bytes
284 uintx region_size = G1HeapRegionSize;
285 if (FLAG_IS_DEFAULT(G1HeapRegionSize)) {
286 // We base the automatic calculation on the min heap size. This
287 // can be problematic if the spread between min and max is quite
288 // wide, imagine -Xms128m -Xmx32g. But, if we decided it based on
289 // the max size, the region size might be way too large for the
290 // min size. Either way, some users might have to set the region
291 // size manually for some -Xms / -Xmx combos.
293 region_size = MAX2(min_heap_size / TARGET_REGION_NUMBER,
294 (uintx) MIN_REGION_SIZE);
295 }
297 int region_size_log = log2_long((jlong) region_size);
298 // Recalculate the region size to make sure it's a power of
299 // 2. This means that region_size is the largest power of 2 that's
300 // <= what we've calculated so far.
301 region_size = ((uintx)1 << region_size_log);
303 // Now make sure that we don't go over or under our limits.
304 if (region_size < MIN_REGION_SIZE) {
305 region_size = MIN_REGION_SIZE;
306 } else if (region_size > MAX_REGION_SIZE) {
307 region_size = MAX_REGION_SIZE;
308 }
310 // And recalculate the log.
311 region_size_log = log2_long((jlong) region_size);
313 // Now, set up the globals.
314 guarantee(LogOfHRGrainBytes == 0, "we should only set it once");
315 LogOfHRGrainBytes = region_size_log;
317 guarantee(LogOfHRGrainWords == 0, "we should only set it once");
318 LogOfHRGrainWords = LogOfHRGrainBytes - LogHeapWordSize;
320 guarantee(GrainBytes == 0, "we should only set it once");
321 // The cast to int is safe, given that we've bounded region_size by
322 // MIN_REGION_SIZE and MAX_REGION_SIZE.
323 GrainBytes = (int) region_size;
325 guarantee(GrainWords == 0, "we should only set it once");
326 GrainWords = GrainBytes >> LogHeapWordSize;
327 guarantee(1 << LogOfHRGrainWords == GrainWords, "sanity");
329 guarantee(CardsPerRegion == 0, "we should only set it once");
330 CardsPerRegion = GrainBytes >> CardTableModRefBS::card_shift;
331 }
333 void HeapRegion::reset_after_compaction() {
334 G1OffsetTableContigSpace::reset_after_compaction();
335 // After a compaction the mark bitmap is invalid, so we must
336 // treat all objects as being inside the unmarked area.
337 zero_marked_bytes();
338 init_top_at_mark_start();
339 }
341 DirtyCardToOopClosure*
342 HeapRegion::new_dcto_closure(OopClosure* cl,
343 CardTableModRefBS::PrecisionStyle precision,
344 HeapRegionDCTOC::FilterKind fk) {
345 return new HeapRegionDCTOC(G1CollectedHeap::heap(),
346 this, cl, precision, fk);
347 }
349 void HeapRegion::hr_clear(bool par, bool clear_space) {
350 assert(_humongous_type == NotHumongous,
351 "we should have already filtered out humongous regions");
352 assert(_humongous_start_region == NULL,
353 "we should have already filtered out humongous regions");
354 assert(_end == _orig_end,
355 "we should have already filtered out humongous regions");
357 _in_collection_set = false;
358 _is_gc_alloc_region = false;
360 set_young_index_in_cset(-1);
361 uninstall_surv_rate_group();
362 set_young_type(NotYoung);
364 if (!par) {
365 // If this is parallel, this will be done later.
366 HeapRegionRemSet* hrrs = rem_set();
367 if (hrrs != NULL) hrrs->clear();
368 _claimed = InitialClaimValue;
369 }
370 zero_marked_bytes();
371 set_sort_index(-1);
373 _offsets.resize(HeapRegion::GrainWords);
374 init_top_at_mark_start();
375 if (clear_space) clear(SpaceDecorator::Mangle);
376 }
378 // <PREDICTION>
379 void HeapRegion::calc_gc_efficiency() {
380 G1CollectedHeap* g1h = G1CollectedHeap::heap();
381 _gc_efficiency = (double) garbage_bytes() /
382 g1h->predict_region_elapsed_time_ms(this, false);
383 }
384 // </PREDICTION>
386 void HeapRegion::set_startsHumongous(HeapWord* new_top, HeapWord* new_end) {
387 assert(!isHumongous(), "sanity / pre-condition");
388 assert(end() == _orig_end,
389 "Should be normal before the humongous object allocation");
390 assert(top() == bottom(), "should be empty");
391 assert(bottom() <= new_top && new_top <= new_end, "pre-condition");
393 _humongous_type = StartsHumongous;
394 _humongous_start_region = this;
396 set_end(new_end);
397 _offsets.set_for_starts_humongous(new_top);
398 }
400 void HeapRegion::set_continuesHumongous(HeapRegion* first_hr) {
401 assert(!isHumongous(), "sanity / pre-condition");
402 assert(end() == _orig_end,
403 "Should be normal before the humongous object allocation");
404 assert(top() == bottom(), "should be empty");
405 assert(first_hr->startsHumongous(), "pre-condition");
407 _humongous_type = ContinuesHumongous;
408 _humongous_start_region = first_hr;
409 }
411 void HeapRegion::set_notHumongous() {
412 assert(isHumongous(), "pre-condition");
414 if (startsHumongous()) {
415 assert(top() <= end(), "pre-condition");
416 set_end(_orig_end);
417 if (top() > end()) {
418 // at least one "continues humongous" region after it
419 set_top(end());
420 }
421 } else {
422 // continues humongous
423 assert(end() == _orig_end, "sanity");
424 }
426 assert(capacity() == (size_t) HeapRegion::GrainBytes, "pre-condition");
427 _humongous_type = NotHumongous;
428 _humongous_start_region = NULL;
429 }
431 bool HeapRegion::claimHeapRegion(jint claimValue) {
432 jint current = _claimed;
433 if (current != claimValue) {
434 jint res = Atomic::cmpxchg(claimValue, &_claimed, current);
435 if (res == current) {
436 return true;
437 }
438 }
439 return false;
440 }
442 HeapWord* HeapRegion::next_block_start_careful(HeapWord* addr) {
443 HeapWord* low = addr;
444 HeapWord* high = end();
445 while (low < high) {
446 size_t diff = pointer_delta(high, low);
447 // Must add one below to bias toward the high amount. Otherwise, if
448 // "high" were at the desired value, and "low" were one less, we
449 // would not converge on "high". This is not symmetric, because
450 // we set "high" to a block start, which might be the right one,
451 // which we don't do for "low".
452 HeapWord* middle = low + (diff+1)/2;
453 if (middle == high) return high;
454 HeapWord* mid_bs = block_start_careful(middle);
455 if (mid_bs < addr) {
456 low = middle;
457 } else {
458 high = mid_bs;
459 }
460 }
461 assert(low == high && low >= addr, "Didn't work.");
462 return low;
463 }
465 void HeapRegion::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
466 G1OffsetTableContigSpace::initialize(mr, false, mangle_space);
467 hr_clear(false/*par*/, clear_space);
468 }
469 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
470 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
471 #endif // _MSC_VER
474 HeapRegion::
475 HeapRegion(G1BlockOffsetSharedArray* sharedOffsetArray,
476 MemRegion mr, bool is_zeroed)
477 : G1OffsetTableContigSpace(sharedOffsetArray, mr, is_zeroed),
478 _next_fk(HeapRegionDCTOC::NoFilterKind),
479 _hrs_index(-1),
480 _humongous_type(NotHumongous), _humongous_start_region(NULL),
481 _in_collection_set(false), _is_gc_alloc_region(false),
482 _next_in_special_set(NULL), _orig_end(NULL),
483 _claimed(InitialClaimValue), _evacuation_failed(false),
484 _prev_marked_bytes(0), _next_marked_bytes(0), _sort_index(-1),
485 _young_type(NotYoung), _next_young_region(NULL),
486 _next_dirty_cards_region(NULL), _next(NULL), _pending_removal(false),
487 #ifdef ASSERT
488 _containing_set(NULL),
489 #endif // ASSERT
490 _young_index_in_cset(-1), _surv_rate_group(NULL), _age_index(-1),
491 _rem_set(NULL), _recorded_rs_length(0), _predicted_elapsed_time_ms(0),
492 _predicted_bytes_to_copy(0)
493 {
494 _orig_end = mr.end();
495 // Note that initialize() will set the start of the unmarked area of the
496 // region.
497 this->initialize(mr, !is_zeroed, SpaceDecorator::Mangle);
498 set_top(bottom());
499 set_saved_mark();
501 _rem_set = new HeapRegionRemSet(sharedOffsetArray, this);
503 assert(HeapRegionRemSet::num_par_rem_sets() > 0, "Invariant.");
504 // In case the region is allocated during a pause, note the top.
505 // We haven't done any counting on a brand new region.
506 _top_at_conc_mark_count = bottom();
507 }
509 class NextCompactionHeapRegionClosure: public HeapRegionClosure {
510 const HeapRegion* _target;
511 bool _target_seen;
512 HeapRegion* _last;
513 CompactibleSpace* _res;
514 public:
515 NextCompactionHeapRegionClosure(const HeapRegion* target) :
516 _target(target), _target_seen(false), _res(NULL) {}
517 bool doHeapRegion(HeapRegion* cur) {
518 if (_target_seen) {
519 if (!cur->isHumongous()) {
520 _res = cur;
521 return true;
522 }
523 } else if (cur == _target) {
524 _target_seen = true;
525 }
526 return false;
527 }
528 CompactibleSpace* result() { return _res; }
529 };
531 CompactibleSpace* HeapRegion::next_compaction_space() const {
532 G1CollectedHeap* g1h = G1CollectedHeap::heap();
533 // cast away const-ness
534 HeapRegion* r = (HeapRegion*) this;
535 NextCompactionHeapRegionClosure blk(r);
536 g1h->heap_region_iterate_from(r, &blk);
537 return blk.result();
538 }
540 void HeapRegion::save_marks() {
541 set_saved_mark();
542 }
544 void HeapRegion::oops_in_mr_iterate(MemRegion mr, OopClosure* cl) {
545 HeapWord* p = mr.start();
546 HeapWord* e = mr.end();
547 oop obj;
548 while (p < e) {
549 obj = oop(p);
550 p += obj->oop_iterate(cl);
551 }
552 assert(p == e, "bad memregion: doesn't end on obj boundary");
553 }
555 #define HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN(OopClosureType, nv_suffix) \
556 void HeapRegion::oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \
557 ContiguousSpace::oop_since_save_marks_iterate##nv_suffix(cl); \
558 }
559 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(HeapRegion_OOP_SINCE_SAVE_MARKS_DEFN)
562 void HeapRegion::oop_before_save_marks_iterate(OopClosure* cl) {
563 oops_in_mr_iterate(MemRegion(bottom(), saved_mark_word()), cl);
564 }
566 HeapWord*
567 HeapRegion::object_iterate_mem_careful(MemRegion mr,
568 ObjectClosure* cl) {
569 G1CollectedHeap* g1h = G1CollectedHeap::heap();
570 // We used to use "block_start_careful" here. But we're actually happy
571 // to update the BOT while we do this...
572 HeapWord* cur = block_start(mr.start());
573 mr = mr.intersection(used_region());
574 if (mr.is_empty()) return NULL;
575 // Otherwise, find the obj that extends onto mr.start().
577 assert(cur <= mr.start()
578 && (oop(cur)->klass_or_null() == NULL ||
579 cur + oop(cur)->size() > mr.start()),
580 "postcondition of block_start");
581 oop obj;
582 while (cur < mr.end()) {
583 obj = oop(cur);
584 if (obj->klass_or_null() == NULL) {
585 // Ran into an unparseable point.
586 return cur;
587 } else if (!g1h->is_obj_dead(obj)) {
588 cl->do_object(obj);
589 }
590 if (cl->abort()) return cur;
591 // The check above must occur before the operation below, since an
592 // abort might invalidate the "size" operation.
593 cur += obj->size();
594 }
595 return NULL;
596 }
598 HeapWord*
599 HeapRegion::
600 oops_on_card_seq_iterate_careful(MemRegion mr,
601 FilterOutOfRegionClosure* cl,
602 bool filter_young) {
603 G1CollectedHeap* g1h = G1CollectedHeap::heap();
605 // If we're within a stop-world GC, then we might look at a card in a
606 // GC alloc region that extends onto a GC LAB, which may not be
607 // parseable. Stop such at the "saved_mark" of the region.
608 if (G1CollectedHeap::heap()->is_gc_active()) {
609 mr = mr.intersection(used_region_at_save_marks());
610 } else {
611 mr = mr.intersection(used_region());
612 }
613 if (mr.is_empty()) return NULL;
614 // Otherwise, find the obj that extends onto mr.start().
616 // The intersection of the incoming mr (for the card) and the
617 // allocated part of the region is non-empty. This implies that
618 // we have actually allocated into this region. The code in
619 // G1CollectedHeap.cpp that allocates a new region sets the
620 // is_young tag on the region before allocating. Thus we
621 // safely know if this region is young.
622 if (is_young() && filter_young) {
623 return NULL;
624 }
626 assert(!is_young(), "check value of filter_young");
628 // We used to use "block_start_careful" here. But we're actually happy
629 // to update the BOT while we do this...
630 HeapWord* cur = block_start(mr.start());
631 assert(cur <= mr.start(), "Postcondition");
633 while (cur <= mr.start()) {
634 if (oop(cur)->klass_or_null() == NULL) {
635 // Ran into an unparseable point.
636 return cur;
637 }
638 // Otherwise...
639 int sz = oop(cur)->size();
640 if (cur + sz > mr.start()) break;
641 // Otherwise, go on.
642 cur = cur + sz;
643 }
644 oop obj;
645 obj = oop(cur);
646 // If we finish this loop...
647 assert(cur <= mr.start()
648 && obj->klass_or_null() != NULL
649 && cur + obj->size() > mr.start(),
650 "Loop postcondition");
651 if (!g1h->is_obj_dead(obj)) {
652 obj->oop_iterate(cl, mr);
653 }
655 HeapWord* next;
656 while (cur < mr.end()) {
657 obj = oop(cur);
658 if (obj->klass_or_null() == NULL) {
659 // Ran into an unparseable point.
660 return cur;
661 };
662 // Otherwise:
663 next = (cur + obj->size());
664 if (!g1h->is_obj_dead(obj)) {
665 if (next < mr.end()) {
666 obj->oop_iterate(cl);
667 } else {
668 // this obj spans the boundary. If it's an array, stop at the
669 // boundary.
670 if (obj->is_objArray()) {
671 obj->oop_iterate(cl, mr);
672 } else {
673 obj->oop_iterate(cl);
674 }
675 }
676 }
677 cur = next;
678 }
679 return NULL;
680 }
682 void HeapRegion::print() const { print_on(gclog_or_tty); }
683 void HeapRegion::print_on(outputStream* st) const {
684 if (isHumongous()) {
685 if (startsHumongous())
686 st->print(" HS");
687 else
688 st->print(" HC");
689 } else {
690 st->print(" ");
691 }
692 if (in_collection_set())
693 st->print(" CS");
694 else if (is_gc_alloc_region())
695 st->print(" A ");
696 else
697 st->print(" ");
698 if (is_young())
699 st->print(is_survivor() ? " SU" : " Y ");
700 else
701 st->print(" ");
702 if (is_empty())
703 st->print(" F");
704 else
705 st->print(" ");
706 st->print(" %5d", _gc_time_stamp);
707 st->print(" PTAMS "PTR_FORMAT" NTAMS "PTR_FORMAT,
708 prev_top_at_mark_start(), next_top_at_mark_start());
709 G1OffsetTableContigSpace::print_on(st);
710 }
712 void HeapRegion::verify(bool allow_dirty) const {
713 bool dummy = false;
714 verify(allow_dirty, /* use_prev_marking */ true, /* failures */ &dummy);
715 }
717 // This really ought to be commoned up into OffsetTableContigSpace somehow.
718 // We would need a mechanism to make that code skip dead objects.
720 void HeapRegion::verify(bool allow_dirty,
721 bool use_prev_marking,
722 bool* failures) const {
723 G1CollectedHeap* g1 = G1CollectedHeap::heap();
724 *failures = false;
725 HeapWord* p = bottom();
726 HeapWord* prev_p = NULL;
727 VerifyLiveClosure vl_cl(g1, use_prev_marking);
728 bool is_humongous = isHumongous();
729 bool do_bot_verify = !is_young();
730 size_t object_num = 0;
731 while (p < top()) {
732 oop obj = oop(p);
733 size_t obj_size = obj->size();
734 object_num += 1;
736 if (is_humongous != g1->isHumongous(obj_size)) {
737 gclog_or_tty->print_cr("obj "PTR_FORMAT" is of %shumongous size ("
738 SIZE_FORMAT" words) in a %shumongous region",
739 p, g1->isHumongous(obj_size) ? "" : "non-",
740 obj_size, is_humongous ? "" : "non-");
741 *failures = true;
742 return;
743 }
745 // If it returns false, verify_for_object() will output the
746 // appropriate messasge.
747 if (do_bot_verify && !_offsets.verify_for_object(p, obj_size)) {
748 *failures = true;
749 return;
750 }
752 if (!g1->is_obj_dead_cond(obj, this, use_prev_marking)) {
753 if (obj->is_oop()) {
754 klassOop klass = obj->klass();
755 if (!klass->is_perm()) {
756 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
757 "not in perm", klass, obj);
758 *failures = true;
759 return;
760 } else if (!klass->is_klass()) {
761 gclog_or_tty->print_cr("klass "PTR_FORMAT" of object "PTR_FORMAT" "
762 "not a klass", klass, obj);
763 *failures = true;
764 return;
765 } else {
766 vl_cl.set_containing_obj(obj);
767 obj->oop_iterate(&vl_cl);
768 if (vl_cl.failures()) {
769 *failures = true;
770 }
771 if (G1MaxVerifyFailures >= 0 &&
772 vl_cl.n_failures() >= G1MaxVerifyFailures) {
773 return;
774 }
775 }
776 } else {
777 gclog_or_tty->print_cr(PTR_FORMAT" no an oop", obj);
778 *failures = true;
779 return;
780 }
781 }
782 prev_p = p;
783 p += obj_size;
784 }
786 if (p != top()) {
787 gclog_or_tty->print_cr("end of last object "PTR_FORMAT" "
788 "does not match top "PTR_FORMAT, p, top());
789 *failures = true;
790 return;
791 }
793 HeapWord* the_end = end();
794 assert(p == top(), "it should still hold");
795 // Do some extra BOT consistency checking for addresses in the
796 // range [top, end). BOT look-ups in this range should yield
797 // top. No point in doing that if top == end (there's nothing there).
798 if (p < the_end) {
799 // Look up top
800 HeapWord* addr_1 = p;
801 HeapWord* b_start_1 = _offsets.block_start_const(addr_1);
802 if (b_start_1 != p) {
803 gclog_or_tty->print_cr("BOT look up for top: "PTR_FORMAT" "
804 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
805 addr_1, b_start_1, p);
806 *failures = true;
807 return;
808 }
810 // Look up top + 1
811 HeapWord* addr_2 = p + 1;
812 if (addr_2 < the_end) {
813 HeapWord* b_start_2 = _offsets.block_start_const(addr_2);
814 if (b_start_2 != p) {
815 gclog_or_tty->print_cr("BOT look up for top + 1: "PTR_FORMAT" "
816 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
817 addr_2, b_start_2, p);
818 *failures = true;
819 return;
820 }
821 }
823 // Look up an address between top and end
824 size_t diff = pointer_delta(the_end, p) / 2;
825 HeapWord* addr_3 = p + diff;
826 if (addr_3 < the_end) {
827 HeapWord* b_start_3 = _offsets.block_start_const(addr_3);
828 if (b_start_3 != p) {
829 gclog_or_tty->print_cr("BOT look up for top + diff: "PTR_FORMAT" "
830 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
831 addr_3, b_start_3, p);
832 *failures = true;
833 return;
834 }
835 }
837 // Loook up end - 1
838 HeapWord* addr_4 = the_end - 1;
839 HeapWord* b_start_4 = _offsets.block_start_const(addr_4);
840 if (b_start_4 != p) {
841 gclog_or_tty->print_cr("BOT look up for end - 1: "PTR_FORMAT" "
842 " yielded "PTR_FORMAT", expecting "PTR_FORMAT,
843 addr_4, b_start_4, p);
844 *failures = true;
845 return;
846 }
847 }
849 if (is_humongous && object_num > 1) {
850 gclog_or_tty->print_cr("region ["PTR_FORMAT","PTR_FORMAT"] is humongous "
851 "but has "SIZE_FORMAT", objects",
852 bottom(), end(), object_num);
853 *failures = true;
854 return;
855 }
856 }
858 // G1OffsetTableContigSpace code; copied from space.cpp. Hope this can go
859 // away eventually.
861 void G1OffsetTableContigSpace::initialize(MemRegion mr, bool clear_space, bool mangle_space) {
862 // false ==> we'll do the clearing if there's clearing to be done.
863 ContiguousSpace::initialize(mr, false, mangle_space);
864 _offsets.zero_bottom_entry();
865 _offsets.initialize_threshold();
866 if (clear_space) clear(mangle_space);
867 }
869 void G1OffsetTableContigSpace::clear(bool mangle_space) {
870 ContiguousSpace::clear(mangle_space);
871 _offsets.zero_bottom_entry();
872 _offsets.initialize_threshold();
873 }
875 void G1OffsetTableContigSpace::set_bottom(HeapWord* new_bottom) {
876 Space::set_bottom(new_bottom);
877 _offsets.set_bottom(new_bottom);
878 }
880 void G1OffsetTableContigSpace::set_end(HeapWord* new_end) {
881 Space::set_end(new_end);
882 _offsets.resize(new_end - bottom());
883 }
885 void G1OffsetTableContigSpace::print() const {
886 print_short();
887 gclog_or_tty->print_cr(" [" INTPTR_FORMAT ", " INTPTR_FORMAT ", "
888 INTPTR_FORMAT ", " INTPTR_FORMAT ")",
889 bottom(), top(), _offsets.threshold(), end());
890 }
892 HeapWord* G1OffsetTableContigSpace::initialize_threshold() {
893 return _offsets.initialize_threshold();
894 }
896 HeapWord* G1OffsetTableContigSpace::cross_threshold(HeapWord* start,
897 HeapWord* end) {
898 _offsets.alloc_block(start, end);
899 return _offsets.threshold();
900 }
902 HeapWord* G1OffsetTableContigSpace::saved_mark_word() const {
903 G1CollectedHeap* g1h = G1CollectedHeap::heap();
904 assert( _gc_time_stamp <= g1h->get_gc_time_stamp(), "invariant" );
905 if (_gc_time_stamp < g1h->get_gc_time_stamp())
906 return top();
907 else
908 return ContiguousSpace::saved_mark_word();
909 }
911 void G1OffsetTableContigSpace::set_saved_mark() {
912 G1CollectedHeap* g1h = G1CollectedHeap::heap();
913 unsigned curr_gc_time_stamp = g1h->get_gc_time_stamp();
915 if (_gc_time_stamp < curr_gc_time_stamp) {
916 // The order of these is important, as another thread might be
917 // about to start scanning this region. If it does so after
918 // set_saved_mark and before _gc_time_stamp = ..., then the latter
919 // will be false, and it will pick up top() as the high water mark
920 // of region. If it does so after _gc_time_stamp = ..., then it
921 // will pick up the right saved_mark_word() as the high water mark
922 // of the region. Either way, the behaviour will be correct.
923 ContiguousSpace::set_saved_mark();
924 OrderAccess::storestore();
925 _gc_time_stamp = curr_gc_time_stamp;
926 // The following fence is to force a flush of the writes above, but
927 // is strictly not needed because when an allocating worker thread
928 // calls set_saved_mark() it does so under the ParGCRareEvent_lock;
929 // when the lock is released, the write will be flushed.
930 // OrderAccess::fence();
931 }
932 }
934 G1OffsetTableContigSpace::
935 G1OffsetTableContigSpace(G1BlockOffsetSharedArray* sharedOffsetArray,
936 MemRegion mr, bool is_zeroed) :
937 _offsets(sharedOffsetArray, mr),
938 _par_alloc_lock(Mutex::leaf, "OffsetTableContigSpace par alloc lock", true),
939 _gc_time_stamp(0)
940 {
941 _offsets.set_space(this);
942 initialize(mr, !is_zeroed, SpaceDecorator::Mangle);
943 }
