1 /*
2 * Copyright (c) 2001, 2012, 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 "classfile/symbolTable.hpp"
27 #include "gc_implementation/g1/concurrentMark.inline.hpp"
28 #include "gc_implementation/g1/concurrentMarkThread.inline.hpp"
29 #include "gc_implementation/g1/g1CollectedHeap.inline.hpp"
30 #include "gc_implementation/g1/g1CollectorPolicy.hpp"
31 #include "gc_implementation/g1/g1ErgoVerbose.hpp"
32 #include "gc_implementation/g1/g1Log.hpp"
33 #include "gc_implementation/g1/g1OopClosures.inline.hpp"
34 #include "gc_implementation/g1/g1RemSet.hpp"
35 #include "gc_implementation/g1/heapRegion.inline.hpp"
36 #include "gc_implementation/g1/heapRegionRemSet.hpp"
37 #include "gc_implementation/g1/heapRegionSeq.inline.hpp"
38 #include "gc_implementation/shared/vmGCOperations.hpp"
39 #include "memory/genOopClosures.inline.hpp"
40 #include "memory/referencePolicy.hpp"
41 #include "memory/resourceArea.hpp"
42 #include "oops/oop.inline.hpp"
43 #include "runtime/handles.inline.hpp"
44 #include "runtime/java.hpp"
45 #include "services/memTracker.hpp"
46
47 // Concurrent marking bit map wrapper
48
49 CMBitMapRO::CMBitMapRO(ReservedSpace rs, int shifter) :
50 _bm((uintptr_t*)NULL,0),
51 _shifter(shifter) {
52 _bmStartWord = (HeapWord*)(rs.base());
53 _bmWordSize = rs.size()/HeapWordSize; // rs.size() is in bytes
54 ReservedSpace brs(ReservedSpace::allocation_align_size_up(
55 (_bmWordSize >> (_shifter + LogBitsPerByte)) + 1));
56
57 MemTracker::record_virtual_memory_type((address)brs.base(), mtGC);
58
59 guarantee(brs.is_reserved(), "couldn't allocate concurrent marking bit map");
60 // For now we'll just commit all of the bit map up fromt.
61 // Later on we'll try to be more parsimonious with swap.
62 guarantee(_virtual_space.initialize(brs, brs.size()),
63 "couldn't reseve backing store for concurrent marking bit map");
64 assert(_virtual_space.committed_size() == brs.size(),
65 "didn't reserve backing store for all of concurrent marking bit map?");
66 _bm.set_map((uintptr_t*)_virtual_space.low());
67 assert(_virtual_space.committed_size() << (_shifter + LogBitsPerByte) >=
68 _bmWordSize, "inconsistency in bit map sizing");
69 _bm.set_size(_bmWordSize >> _shifter);
70 }
71
72 HeapWord* CMBitMapRO::getNextMarkedWordAddress(HeapWord* addr,
73 HeapWord* limit) const {
74 // First we must round addr *up* to a possible object boundary.
75 addr = (HeapWord*)align_size_up((intptr_t)addr,
76 HeapWordSize << _shifter);
77 size_t addrOffset = heapWordToOffset(addr);
78 if (limit == NULL) {
79 limit = _bmStartWord + _bmWordSize;
80 }
81 size_t limitOffset = heapWordToOffset(limit);
82 size_t nextOffset = _bm.get_next_one_offset(addrOffset, limitOffset);
83 HeapWord* nextAddr = offsetToHeapWord(nextOffset);
84 assert(nextAddr >= addr, "get_next_one postcondition");
85 assert(nextAddr == limit || isMarked(nextAddr),
86 "get_next_one postcondition");
87 return nextAddr;
88 }
89
90 HeapWord* CMBitMapRO::getNextUnmarkedWordAddress(HeapWord* addr,
91 HeapWord* limit) const {
92 size_t addrOffset = heapWordToOffset(addr);
93 if (limit == NULL) {
94 limit = _bmStartWord + _bmWordSize;
95 }
96 size_t limitOffset = heapWordToOffset(limit);
97 size_t nextOffset = _bm.get_next_zero_offset(addrOffset, limitOffset);
98 HeapWord* nextAddr = offsetToHeapWord(nextOffset);
99 assert(nextAddr >= addr, "get_next_one postcondition");
100 assert(nextAddr == limit || !isMarked(nextAddr),
101 "get_next_one postcondition");
102 return nextAddr;
103 }
104
105 int CMBitMapRO::heapWordDiffToOffsetDiff(size_t diff) const {
106 assert((diff & ((1 << _shifter) - 1)) == 0, "argument check");
107 return (int) (diff >> _shifter);
108 }
109
110 #ifndef PRODUCT
111 bool CMBitMapRO::covers(ReservedSpace rs) const {
112 // assert(_bm.map() == _virtual_space.low(), "map inconsistency");
113 assert(((size_t)_bm.size() * ((size_t)1 << _shifter)) == _bmWordSize,
114 "size inconsistency");
115 return _bmStartWord == (HeapWord*)(rs.base()) &&
116 _bmWordSize == rs.size()>>LogHeapWordSize;
117 }
118 #endif
119
120 void CMBitMap::clearAll() {
121 _bm.clear();
122 return;
123 }
124
125 void CMBitMap::markRange(MemRegion mr) {
126 mr.intersection(MemRegion(_bmStartWord, _bmWordSize));
127 assert(!mr.is_empty(), "unexpected empty region");
128 assert((offsetToHeapWord(heapWordToOffset(mr.end())) ==
129 ((HeapWord *) mr.end())),
130 "markRange memory region end is not card aligned");
131 // convert address range into offset range
132 _bm.at_put_range(heapWordToOffset(mr.start()),
133 heapWordToOffset(mr.end()), true);
134 }
135
136 void CMBitMap::clearRange(MemRegion mr) {
137 mr.intersection(MemRegion(_bmStartWord, _bmWordSize));
138 assert(!mr.is_empty(), "unexpected empty region");
139 // convert address range into offset range
140 _bm.at_put_range(heapWordToOffset(mr.start()),
141 heapWordToOffset(mr.end()), false);
142 }
143
144 MemRegion CMBitMap::getAndClearMarkedRegion(HeapWord* addr,
145 HeapWord* end_addr) {
146 HeapWord* start = getNextMarkedWordAddress(addr);
147 start = MIN2(start, end_addr);
148 HeapWord* end = getNextUnmarkedWordAddress(start);
149 end = MIN2(end, end_addr);
150 assert(start <= end, "Consistency check");
151 MemRegion mr(start, end);
152 if (!mr.is_empty()) {
153 clearRange(mr);
154 }
155 return mr;
156 }
157
158 CMMarkStack::CMMarkStack(ConcurrentMark* cm) :
159 _base(NULL), _cm(cm)
160 #ifdef ASSERT
161 , _drain_in_progress(false)
162 , _drain_in_progress_yields(false)
163 #endif
164 {}
165
166 void CMMarkStack::allocate(size_t size) {
167 _base = NEW_C_HEAP_ARRAY(oop, size, mtGC);
168 if (_base == NULL) {
169 vm_exit_during_initialization("Failed to allocate CM region mark stack");
170 }
171 _index = 0;
172 _capacity = (jint) size;
173 _saved_index = -1;
174 NOT_PRODUCT(_max_depth = 0);
175 }
176
177 CMMarkStack::~CMMarkStack() {
178 if (_base != NULL) {
179 FREE_C_HEAP_ARRAY(oop, _base, mtGC);
180 }
181 }
182
183 void CMMarkStack::par_push(oop ptr) {
184 while (true) {
185 if (isFull()) {
186 _overflow = true;
187 return;
188 }
189 // Otherwise...
190 jint index = _index;
191 jint next_index = index+1;
192 jint res = Atomic::cmpxchg(next_index, &_index, index);
193 if (res == index) {
194 _base[index] = ptr;
195 // Note that we don't maintain this atomically. We could, but it
196 // doesn't seem necessary.
197 NOT_PRODUCT(_max_depth = MAX2(_max_depth, next_index));
198 return;
199 }
200 // Otherwise, we need to try again.
201 }
202 }
203
204 void CMMarkStack::par_adjoin_arr(oop* ptr_arr, int n) {
205 while (true) {
206 if (isFull()) {
207 _overflow = true;
208 return;
209 }
210 // Otherwise...
211 jint index = _index;
212 jint next_index = index + n;
213 if (next_index > _capacity) {
214 _overflow = true;
215 return;
216 }
217 jint res = Atomic::cmpxchg(next_index, &_index, index);
218 if (res == index) {
219 for (int i = 0; i < n; i++) {
220 int ind = index + i;
221 assert(ind < _capacity, "By overflow test above.");
222 _base[ind] = ptr_arr[i];
223 }
224 NOT_PRODUCT(_max_depth = MAX2(_max_depth, next_index));
225 return;
226 }
227 // Otherwise, we need to try again.
228 }
229 }
230
231
232 void CMMarkStack::par_push_arr(oop* ptr_arr, int n) {
233 MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag);
234 jint start = _index;
235 jint next_index = start + n;
236 if (next_index > _capacity) {
237 _overflow = true;
238 return;
239 }
240 // Otherwise.
241 _index = next_index;
242 for (int i = 0; i < n; i++) {
243 int ind = start + i;
244 assert(ind < _capacity, "By overflow test above.");
245 _base[ind] = ptr_arr[i];
246 }
247 }
248
249
250 bool CMMarkStack::par_pop_arr(oop* ptr_arr, int max, int* n) {
251 MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag);
252 jint index = _index;
253 if (index == 0) {
254 *n = 0;
255 return false;
256 } else {
257 int k = MIN2(max, index);
258 jint new_ind = index - k;
259 for (int j = 0; j < k; j++) {
260 ptr_arr[j] = _base[new_ind + j];
261 }
262 _index = new_ind;
263 *n = k;
264 return true;
265 }
266 }
267
268 template<class OopClosureClass>
269 bool CMMarkStack::drain(OopClosureClass* cl, CMBitMap* bm, bool yield_after) {
270 assert(!_drain_in_progress || !_drain_in_progress_yields || yield_after
271 || SafepointSynchronize::is_at_safepoint(),
272 "Drain recursion must be yield-safe.");
273 bool res = true;
274 debug_only(_drain_in_progress = true);
275 debug_only(_drain_in_progress_yields = yield_after);
276 while (!isEmpty()) {
277 oop newOop = pop();
278 assert(G1CollectedHeap::heap()->is_in_reserved(newOop), "Bad pop");
279 assert(newOop->is_oop(), "Expected an oop");
280 assert(bm == NULL || bm->isMarked((HeapWord*)newOop),
281 "only grey objects on this stack");
282 newOop->oop_iterate(cl);
283 if (yield_after && _cm->do_yield_check()) {
284 res = false;
285 break;
286 }
287 }
288 debug_only(_drain_in_progress = false);
289 return res;
290 }
291
292 void CMMarkStack::note_start_of_gc() {
293 assert(_saved_index == -1,
294 "note_start_of_gc()/end_of_gc() bracketed incorrectly");
295 _saved_index = _index;
296 }
297
298 void CMMarkStack::note_end_of_gc() {
299 // This is intentionally a guarantee, instead of an assert. If we
300 // accidentally add something to the mark stack during GC, it
301 // will be a correctness issue so it's better if we crash. we'll
302 // only check this once per GC anyway, so it won't be a performance
303 // issue in any way.
304 guarantee(_saved_index == _index,
305 err_msg("saved index: %d index: %d", _saved_index, _index));
306 _saved_index = -1;
307 }
308
309 void CMMarkStack::oops_do(OopClosure* f) {
310 assert(_saved_index == _index,
311 err_msg("saved index: %d index: %d", _saved_index, _index));
312 for (int i = 0; i < _index; i += 1) {
313 f->do_oop(&_base[i]);
314 }
315 }
316
317 bool ConcurrentMark::not_yet_marked(oop obj) const {
318 return (_g1h->is_obj_ill(obj)
319 || (_g1h->is_in_permanent(obj)
320 && !nextMarkBitMap()->isMarked((HeapWord*)obj)));
321 }
322
323 CMRootRegions::CMRootRegions() :
324 _young_list(NULL), _cm(NULL), _scan_in_progress(false),
325 _should_abort(false), _next_survivor(NULL) { }
326
327 void CMRootRegions::init(G1CollectedHeap* g1h, ConcurrentMark* cm) {
328 _young_list = g1h->young_list();
329 _cm = cm;
330 }
331
332 void CMRootRegions::prepare_for_scan() {
333 assert(!scan_in_progress(), "pre-condition");
334
335 // Currently, only survivors can be root regions.
336 assert(_next_survivor == NULL, "pre-condition");
337 _next_survivor = _young_list->first_survivor_region();
338 _scan_in_progress = (_next_survivor != NULL);
339 _should_abort = false;
340 }
341
342 HeapRegion* CMRootRegions::claim_next() {
343 if (_should_abort) {
344 // If someone has set the should_abort flag, we return NULL to
345 // force the caller to bail out of their loop.
346 return NULL;
347 }
348
349 // Currently, only survivors can be root regions.
350 HeapRegion* res = _next_survivor;
351 if (res != NULL) {
352 MutexLockerEx x(RootRegionScan_lock, Mutex::_no_safepoint_check_flag);
353 // Read it again in case it changed while we were waiting for the lock.
354 res = _next_survivor;
355 if (res != NULL) {
356 if (res == _young_list->last_survivor_region()) {
357 // We just claimed the last survivor so store NULL to indicate
358 // that we're done.
359 _next_survivor = NULL;
360 } else {
361 _next_survivor = res->get_next_young_region();
362 }
363 } else {
364 // Someone else claimed the last survivor while we were trying
365 // to take the lock so nothing else to do.
366 }
367 }
368 assert(res == NULL || res->is_survivor(), "post-condition");
369
370 return res;
371 }
372
373 void CMRootRegions::scan_finished() {
374 assert(scan_in_progress(), "pre-condition");
375
376 // Currently, only survivors can be root regions.
377 if (!_should_abort) {
378 assert(_next_survivor == NULL, "we should have claimed all survivors");
379 }
380 _next_survivor = NULL;
381
382 {
383 MutexLockerEx x(RootRegionScan_lock, Mutex::_no_safepoint_check_flag);
384 _scan_in_progress = false;
385 RootRegionScan_lock->notify_all();
386 }
387 }
388
389 bool CMRootRegions::wait_until_scan_finished() {
390 if (!scan_in_progress()) return false;
391
392 {
393 MutexLockerEx x(RootRegionScan_lock, Mutex::_no_safepoint_check_flag);
394 while (scan_in_progress()) {
395 RootRegionScan_lock->wait(Mutex::_no_safepoint_check_flag);
396 }
397 }
398 return true;
399 }
400
401 #ifdef _MSC_VER // the use of 'this' below gets a warning, make it go away
402 #pragma warning( disable:4355 ) // 'this' : used in base member initializer list
403 #endif // _MSC_VER
404
405 uint ConcurrentMark::scale_parallel_threads(uint n_par_threads) {
406 return MAX2((n_par_threads + 2) / 4, 1U);
407 }
408
409 ConcurrentMark::ConcurrentMark(ReservedSpace rs, uint max_regions) :
410 _markBitMap1(rs, MinObjAlignment - 1),
411 _markBitMap2(rs, MinObjAlignment - 1),
412
413 _parallel_marking_threads(0),
414 _max_parallel_marking_threads(0),
415 _sleep_factor(0.0),
416 _marking_task_overhead(1.0),
417 _cleanup_sleep_factor(0.0),
418 _cleanup_task_overhead(1.0),
419 _cleanup_list("Cleanup List"),
420 _region_bm((BitMap::idx_t) max_regions, false /* in_resource_area*/),
421 _card_bm((rs.size() + CardTableModRefBS::card_size - 1) >>
422 CardTableModRefBS::card_shift,
423 false /* in_resource_area*/),
424
425 _prevMarkBitMap(&_markBitMap1),
426 _nextMarkBitMap(&_markBitMap2),
427
428 _markStack(this),
429 // _finger set in set_non_marking_state
430
431 _max_task_num(MAX2((uint)ParallelGCThreads, 1U)),
432 // _active_tasks set in set_non_marking_state
433 // _tasks set inside the constructor
434 _task_queues(new CMTaskQueueSet((int) _max_task_num)),
435 _terminator(ParallelTaskTerminator((int) _max_task_num, _task_queues)),
436
437 _has_overflown(false),
438 _concurrent(false),
439 _has_aborted(false),
440 _restart_for_overflow(false),
441 _concurrent_marking_in_progress(false),
442
443 // _verbose_level set below
444
445 _init_times(),
446 _remark_times(), _remark_mark_times(), _remark_weak_ref_times(),
447 _cleanup_times(),
448 _total_counting_time(0.0),
449 _total_rs_scrub_time(0.0),
450
451 _parallel_workers(NULL),
452
453 _count_card_bitmaps(NULL),
454 _count_marked_bytes(NULL) {
455 CMVerboseLevel verbose_level = (CMVerboseLevel) G1MarkingVerboseLevel;
456 if (verbose_level < no_verbose) {
457 verbose_level = no_verbose;
458 }
459 if (verbose_level > high_verbose) {
460 verbose_level = high_verbose;
461 }
462 _verbose_level = verbose_level;
463
464 if (verbose_low()) {
465 gclog_or_tty->print_cr("[global] init, heap start = "PTR_FORMAT", "
466 "heap end = "PTR_FORMAT, _heap_start, _heap_end);
467 }
468
469 _markStack.allocate(MarkStackSize);
470
471 // Create & start a ConcurrentMark thread.
472 _cmThread = new ConcurrentMarkThread(this);
473 assert(cmThread() != NULL, "CM Thread should have been created");
474 assert(cmThread()->cm() != NULL, "CM Thread should refer to this cm");
475
476 _g1h = G1CollectedHeap::heap();
477 assert(CGC_lock != NULL, "Where's the CGC_lock?");
478 assert(_markBitMap1.covers(rs), "_markBitMap1 inconsistency");
479 assert(_markBitMap2.covers(rs), "_markBitMap2 inconsistency");
480
481 SATBMarkQueueSet& satb_qs = JavaThread::satb_mark_queue_set();
482 satb_qs.set_buffer_size(G1SATBBufferSize);
483
484 _root_regions.init(_g1h, this);
485
486 _tasks = NEW_C_HEAP_ARRAY(CMTask*, _max_task_num, mtGC);
487 _accum_task_vtime = NEW_C_HEAP_ARRAY(double, _max_task_num, mtGC);
488
489 _count_card_bitmaps = NEW_C_HEAP_ARRAY(BitMap, _max_task_num, mtGC);
490 _count_marked_bytes = NEW_C_HEAP_ARRAY(size_t*, _max_task_num, mtGC);
491
492 BitMap::idx_t card_bm_size = _card_bm.size();
493
494 // so that the assertion in MarkingTaskQueue::task_queue doesn't fail
495 _active_tasks = _max_task_num;
496 for (int i = 0; i < (int) _max_task_num; ++i) {
497 CMTaskQueue* task_queue = new CMTaskQueue();
498 task_queue->initialize();
499 _task_queues->register_queue(i, task_queue);
500
501 _count_card_bitmaps[i] = BitMap(card_bm_size, false);
502 _count_marked_bytes[i] = NEW_C_HEAP_ARRAY(size_t, (size_t) max_regions, mtGC);
503
504 _tasks[i] = new CMTask(i, this,
505 _count_marked_bytes[i],
506 &_count_card_bitmaps[i],
507 task_queue, _task_queues);
508
509 _accum_task_vtime[i] = 0.0;
510 }
511
512 // Calculate the card number for the bottom of the heap. Used
513 // in biasing indexes into the accounting card bitmaps.
514 _heap_bottom_card_num =
515 intptr_t(uintptr_t(_g1h->reserved_region().start()) >>
516 CardTableModRefBS::card_shift);
517
518 // Clear all the liveness counting data
519 clear_all_count_data();
520
521 if (ConcGCThreads > ParallelGCThreads) {
522 vm_exit_during_initialization("Can't have more ConcGCThreads "
523 "than ParallelGCThreads.");
524 }
525 if (ParallelGCThreads == 0) {
526 // if we are not running with any parallel GC threads we will not
527 // spawn any marking threads either
528 _parallel_marking_threads = 0;
529 _max_parallel_marking_threads = 0;
530 _sleep_factor = 0.0;
531 _marking_task_overhead = 1.0;
532 } else {
533 if (ConcGCThreads > 0) {
534 // notice that ConcGCThreads overwrites G1MarkingOverheadPercent
535 // if both are set
536
537 _parallel_marking_threads = (uint) ConcGCThreads;
538 _max_parallel_marking_threads = _parallel_marking_threads;
539 _sleep_factor = 0.0;
540 _marking_task_overhead = 1.0;
541 } else if (G1MarkingOverheadPercent > 0) {
542 // we will calculate the number of parallel marking threads
543 // based on a target overhead with respect to the soft real-time
544 // goal
545
546 double marking_overhead = (double) G1MarkingOverheadPercent / 100.0;
547 double overall_cm_overhead =
548 (double) MaxGCPauseMillis * marking_overhead /
549 (double) GCPauseIntervalMillis;
550 double cpu_ratio = 1.0 / (double) os::processor_count();
551 double marking_thread_num = ceil(overall_cm_overhead / cpu_ratio);
552 double marking_task_overhead =
553 overall_cm_overhead / marking_thread_num *
554 (double) os::processor_count();
555 double sleep_factor =
556 (1.0 - marking_task_overhead) / marking_task_overhead;
557
558 _parallel_marking_threads = (uint) marking_thread_num;
559 _max_parallel_marking_threads = _parallel_marking_threads;
560 _sleep_factor = sleep_factor;
561 _marking_task_overhead = marking_task_overhead;
562 } else {
563 _parallel_marking_threads = scale_parallel_threads((uint)ParallelGCThreads);
564 _max_parallel_marking_threads = _parallel_marking_threads;
565 _sleep_factor = 0.0;
566 _marking_task_overhead = 1.0;
567 }
568
569 if (parallel_marking_threads() > 1) {
570 _cleanup_task_overhead = 1.0;
571 } else {
572 _cleanup_task_overhead = marking_task_overhead();
573 }
574 _cleanup_sleep_factor =
575 (1.0 - cleanup_task_overhead()) / cleanup_task_overhead();
576
577 #if 0
578 gclog_or_tty->print_cr("Marking Threads %d", parallel_marking_threads());
579 gclog_or_tty->print_cr("CM Marking Task Overhead %1.4lf", marking_task_overhead());
580 gclog_or_tty->print_cr("CM Sleep Factor %1.4lf", sleep_factor());
581 gclog_or_tty->print_cr("CL Marking Task Overhead %1.4lf", cleanup_task_overhead());
582 gclog_or_tty->print_cr("CL Sleep Factor %1.4lf", cleanup_sleep_factor());
583 #endif
584
585 guarantee(parallel_marking_threads() > 0, "peace of mind");
586 _parallel_workers = new FlexibleWorkGang("G1 Parallel Marking Threads",
587 _max_parallel_marking_threads, false, true);
588 if (_parallel_workers == NULL) {
589 vm_exit_during_initialization("Failed necessary allocation.");
590 } else {
591 _parallel_workers->initialize_workers();
592 }
593 }
594
595 // so that the call below can read a sensible value
596 _heap_start = (HeapWord*) rs.base();
597 set_non_marking_state();
598 }
599
600 void ConcurrentMark::update_g1_committed(bool force) {
601 // If concurrent marking is not in progress, then we do not need to
602 // update _heap_end.
603 if (!concurrent_marking_in_progress() && !force) return;
604
605 MemRegion committed = _g1h->g1_committed();
606 assert(committed.start() == _heap_start, "start shouldn't change");
607 HeapWord* new_end = committed.end();
608 if (new_end > _heap_end) {
609 // The heap has been expanded.
610
611 _heap_end = new_end;
612 }
613 // Notice that the heap can also shrink. However, this only happens
614 // during a Full GC (at least currently) and the entire marking
615 // phase will bail out and the task will not be restarted. So, let's
616 // do nothing.
617 }
618
619 void ConcurrentMark::reset() {
620 // Starting values for these two. This should be called in a STW
621 // phase. CM will be notified of any future g1_committed expansions
622 // will be at the end of evacuation pauses, when tasks are
623 // inactive.
624 MemRegion committed = _g1h->g1_committed();
625 _heap_start = committed.start();
626 _heap_end = committed.end();
627
628 // Separated the asserts so that we know which one fires.
629 assert(_heap_start != NULL, "heap bounds should look ok");
630 assert(_heap_end != NULL, "heap bounds should look ok");
631 assert(_heap_start < _heap_end, "heap bounds should look ok");
632
633 // reset all the marking data structures and any necessary flags
634 clear_marking_state();
635
636 if (verbose_low()) {
637 gclog_or_tty->print_cr("[global] resetting");
638 }
639
640 // We do reset all of them, since different phases will use
641 // different number of active threads. So, it's easiest to have all
642 // of them ready.
643 for (int i = 0; i < (int) _max_task_num; ++i) {
644 _tasks[i]->reset(_nextMarkBitMap);
645 }
646
647 // we need this to make sure that the flag is on during the evac
648 // pause with initial mark piggy-backed
649 set_concurrent_marking_in_progress();
650 }
651
652 void ConcurrentMark::set_phase(uint active_tasks, bool concurrent) {
653 assert(active_tasks <= _max_task_num, "we should not have more");
654
655 _active_tasks = active_tasks;
656 // Need to update the three data structures below according to the
657 // number of active threads for this phase.
658 _terminator = ParallelTaskTerminator((int) active_tasks, _task_queues);
659 _first_overflow_barrier_sync.set_n_workers((int) active_tasks);
660 _second_overflow_barrier_sync.set_n_workers((int) active_tasks);
661
662 _concurrent = concurrent;
663 // We propagate this to all tasks, not just the active ones.
664 for (int i = 0; i < (int) _max_task_num; ++i)
665 _tasks[i]->set_concurrent(concurrent);
666
667 if (concurrent) {
668 set_concurrent_marking_in_progress();
669 } else {
670 // We currently assume that the concurrent flag has been set to
671 // false before we start remark. At this point we should also be
672 // in a STW phase.
673 assert(!concurrent_marking_in_progress(), "invariant");
674 assert(_finger == _heap_end, "only way to get here");
675 update_g1_committed(true);
676 }
677 }
678
679 void ConcurrentMark::set_non_marking_state() {
680 // We set the global marking state to some default values when we're
681 // not doing marking.
682 clear_marking_state();
683 _active_tasks = 0;
684 clear_concurrent_marking_in_progress();
685 }
686
687 ConcurrentMark::~ConcurrentMark() {
688 // The ConcurrentMark instance is never freed.
689 ShouldNotReachHere();
690 }
691
692 void ConcurrentMark::clearNextBitmap() {
693 G1CollectedHeap* g1h = G1CollectedHeap::heap();
694 G1CollectorPolicy* g1p = g1h->g1_policy();
695
696 // Make sure that the concurrent mark thread looks to still be in
697 // the current cycle.
698 guarantee(cmThread()->during_cycle(), "invariant");
699
700 // We are finishing up the current cycle by clearing the next
701 // marking bitmap and getting it ready for the next cycle. During
702 // this time no other cycle can start. So, let's make sure that this
703 // is the case.
704 guarantee(!g1h->mark_in_progress(), "invariant");
705
706 // clear the mark bitmap (no grey objects to start with).
707 // We need to do this in chunks and offer to yield in between
708 // each chunk.
709 HeapWord* start = _nextMarkBitMap->startWord();
710 HeapWord* end = _nextMarkBitMap->endWord();
711 HeapWord* cur = start;
712 size_t chunkSize = M;
713 while (cur < end) {
714 HeapWord* next = cur + chunkSize;
715 if (next > end) {
716 next = end;
717 }
718 MemRegion mr(cur,next);
719 _nextMarkBitMap->clearRange(mr);
720 cur = next;
721 do_yield_check();
722
723 // Repeat the asserts from above. We'll do them as asserts here to
724 // minimize their overhead on the product. However, we'll have
725 // them as guarantees at the beginning / end of the bitmap
726 // clearing to get some checking in the product.
727 assert(cmThread()->during_cycle(), "invariant");
728 assert(!g1h->mark_in_progress(), "invariant");
729 }
730
731 // Clear the liveness counting data
732 clear_all_count_data();
733
734 // Repeat the asserts from above.
735 guarantee(cmThread()->during_cycle(), "invariant");
736 guarantee(!g1h->mark_in_progress(), "invariant");
737 }
738
739 class NoteStartOfMarkHRClosure: public HeapRegionClosure {
740 public:
741 bool doHeapRegion(HeapRegion* r) {
742 if (!r->continuesHumongous()) {
743 r->note_start_of_marking();
744 }
745 return false;
746 }
747 };
748
749 void ConcurrentMark::checkpointRootsInitialPre() {
750 G1CollectedHeap* g1h = G1CollectedHeap::heap();
751 G1CollectorPolicy* g1p = g1h->g1_policy();
752
753 _has_aborted = false;
754
755 #ifndef PRODUCT
756 if (G1PrintReachableAtInitialMark) {
757 print_reachable("at-cycle-start",
758 VerifyOption_G1UsePrevMarking, true /* all */);
759 }
760 #endif
761
762 // Initialise marking structures. This has to be done in a STW phase.
763 reset();
764
765 // For each region note start of marking.
766 NoteStartOfMarkHRClosure startcl;
767 g1h->heap_region_iterate(&startcl);
768 }
769
770
771 void ConcurrentMark::checkpointRootsInitialPost() {
772 G1CollectedHeap* g1h = G1CollectedHeap::heap();
773
774 // If we force an overflow during remark, the remark operation will
775 // actually abort and we'll restart concurrent marking. If we always
776 // force an oveflow during remark we'll never actually complete the
777 // marking phase. So, we initilize this here, at the start of the
778 // cycle, so that at the remaining overflow number will decrease at
779 // every remark and we'll eventually not need to cause one.
780 force_overflow_stw()->init();
781
782 // Start Concurrent Marking weak-reference discovery.
783 ReferenceProcessor* rp = g1h->ref_processor_cm();
784 // enable ("weak") refs discovery
785 rp->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
786 rp->setup_policy(false); // snapshot the soft ref policy to be used in this cycle
787
788 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set();
789 // This is the start of the marking cycle, we're expected all
790 // threads to have SATB queues with active set to false.
791 satb_mq_set.set_active_all_threads(true, /* new active value */
792 false /* expected_active */);
793
794 _root_regions.prepare_for_scan();
795
796 // update_g1_committed() will be called at the end of an evac pause
797 // when marking is on. So, it's also called at the end of the
798 // initial-mark pause to update the heap end, if the heap expands
799 // during it. No need to call it here.
800 }
801
802 /*
803 * Notice that in the next two methods, we actually leave the STS
804 * during the barrier sync and join it immediately afterwards. If we
805 * do not do this, the following deadlock can occur: one thread could
806 * be in the barrier sync code, waiting for the other thread to also
807 * sync up, whereas another one could be trying to yield, while also
808 * waiting for the other threads to sync up too.
809 *
810 * Note, however, that this code is also used during remark and in
811 * this case we should not attempt to leave / enter the STS, otherwise
812 * we'll either hit an asseert (debug / fastdebug) or deadlock
813 * (product). So we should only leave / enter the STS if we are
814 * operating concurrently.
815 *
816 * Because the thread that does the sync barrier has left the STS, it
817 * is possible to be suspended for a Full GC or an evacuation pause
818 * could occur. This is actually safe, since the entering the sync
819 * barrier is one of the last things do_marking_step() does, and it
820 * doesn't manipulate any data structures afterwards.
821 */
822
823 void ConcurrentMark::enter_first_sync_barrier(int task_num) {
824 if (verbose_low()) {
825 gclog_or_tty->print_cr("[%d] entering first barrier", task_num);
826 }
827
828 if (concurrent()) {
829 ConcurrentGCThread::stsLeave();
830 }
831 _first_overflow_barrier_sync.enter();
832 if (concurrent()) {
833 ConcurrentGCThread::stsJoin();
834 }
835 // at this point everyone should have synced up and not be doing any
836 // more work
837
838 if (verbose_low()) {
839 gclog_or_tty->print_cr("[%d] leaving first barrier", task_num);
840 }
841
842 // let task 0 do this
843 if (task_num == 0) {
844 // task 0 is responsible for clearing the global data structures
845 // We should be here because of an overflow. During STW we should
846 // not clear the overflow flag since we rely on it being true when
847 // we exit this method to abort the pause and restart concurent
848 // marking.
849 clear_marking_state(concurrent() /* clear_overflow */);
850 force_overflow()->update();
851
852 if (G1Log::fine()) {
853 gclog_or_tty->date_stamp(PrintGCDateStamps);
854 gclog_or_tty->stamp(PrintGCTimeStamps);
855 gclog_or_tty->print_cr("[GC concurrent-mark-reset-for-overflow]");
856 }
857 }
858
859 // after this, each task should reset its own data structures then
860 // then go into the second barrier
861 }
862
863 void ConcurrentMark::enter_second_sync_barrier(int task_num) {
864 if (verbose_low()) {
865 gclog_or_tty->print_cr("[%d] entering second barrier", task_num);
866 }
867
868 if (concurrent()) {
869 ConcurrentGCThread::stsLeave();
870 }
871 _second_overflow_barrier_sync.enter();
872 if (concurrent()) {
873 ConcurrentGCThread::stsJoin();
874 }
875 // at this point everything should be re-initialised and ready to go
876
877 if (verbose_low()) {
878 gclog_or_tty->print_cr("[%d] leaving second barrier", task_num);
879 }
880 }
881
882 #ifndef PRODUCT
883 void ForceOverflowSettings::init() {
884 _num_remaining = G1ConcMarkForceOverflow;
885 _force = false;
886 update();
887 }
888
889 void ForceOverflowSettings::update() {
890 if (_num_remaining > 0) {
891 _num_remaining -= 1;
892 _force = true;
893 } else {
894 _force = false;
895 }
896 }
897
898 bool ForceOverflowSettings::should_force() {
899 if (_force) {
900 _force = false;
901 return true;
902 } else {
903 return false;
904 }
905 }
906 #endif // !PRODUCT
907
908 class CMConcurrentMarkingTask: public AbstractGangTask {
909 private:
910 ConcurrentMark* _cm;
911 ConcurrentMarkThread* _cmt;
912
913 public:
914 void work(uint worker_id) {
915 assert(Thread::current()->is_ConcurrentGC_thread(),
916 "this should only be done by a conc GC thread");
917 ResourceMark rm;
918
919 double start_vtime = os::elapsedVTime();
920
921 ConcurrentGCThread::stsJoin();
922
923 assert(worker_id < _cm->active_tasks(), "invariant");
924 CMTask* the_task = _cm->task(worker_id);
925 the_task->record_start_time();
926 if (!_cm->has_aborted()) {
927 do {
928 double start_vtime_sec = os::elapsedVTime();
929 double start_time_sec = os::elapsedTime();
930 double mark_step_duration_ms = G1ConcMarkStepDurationMillis;
931
932 the_task->do_marking_step(mark_step_duration_ms,
933 true /* do_stealing */,
934 true /* do_termination */);
935
936 double end_time_sec = os::elapsedTime();
937 double end_vtime_sec = os::elapsedVTime();
938 double elapsed_vtime_sec = end_vtime_sec - start_vtime_sec;
939 double elapsed_time_sec = end_time_sec - start_time_sec;
940 _cm->clear_has_overflown();
941
942 bool ret = _cm->do_yield_check(worker_id);
943
944 jlong sleep_time_ms;
945 if (!_cm->has_aborted() && the_task->has_aborted()) {
946 sleep_time_ms =
947 (jlong) (elapsed_vtime_sec * _cm->sleep_factor() * 1000.0);
948 ConcurrentGCThread::stsLeave();
949 os::sleep(Thread::current(), sleep_time_ms, false);
950 ConcurrentGCThread::stsJoin();
951 }
952 double end_time2_sec = os::elapsedTime();
953 double elapsed_time2_sec = end_time2_sec - start_time_sec;
954
955 #if 0
956 gclog_or_tty->print_cr("CM: elapsed %1.4lf ms, sleep %1.4lf ms, "
957 "overhead %1.4lf",
958 elapsed_vtime_sec * 1000.0, (double) sleep_time_ms,
959 the_task->conc_overhead(os::elapsedTime()) * 8.0);
960 gclog_or_tty->print_cr("elapsed time %1.4lf ms, time 2: %1.4lf ms",
961 elapsed_time_sec * 1000.0, elapsed_time2_sec * 1000.0);
962 #endif
963 } while (!_cm->has_aborted() && the_task->has_aborted());
964 }
965 the_task->record_end_time();
966 guarantee(!the_task->has_aborted() || _cm->has_aborted(), "invariant");
967
968 ConcurrentGCThread::stsLeave();
969
970 double end_vtime = os::elapsedVTime();
971 _cm->update_accum_task_vtime(worker_id, end_vtime - start_vtime);
972 }
973
974 CMConcurrentMarkingTask(ConcurrentMark* cm,
975 ConcurrentMarkThread* cmt) :
976 AbstractGangTask("Concurrent Mark"), _cm(cm), _cmt(cmt) { }
977
978 ~CMConcurrentMarkingTask() { }
979 };
980
981 // Calculates the number of active workers for a concurrent
982 // phase.
983 uint ConcurrentMark::calc_parallel_marking_threads() {
984 if (G1CollectedHeap::use_parallel_gc_threads()) {
985 uint n_conc_workers = 0;
986 if (!UseDynamicNumberOfGCThreads ||
987 (!FLAG_IS_DEFAULT(ConcGCThreads) &&
988 !ForceDynamicNumberOfGCThreads)) {
989 n_conc_workers = max_parallel_marking_threads();
990 } else {
991 n_conc_workers =
992 AdaptiveSizePolicy::calc_default_active_workers(
993 max_parallel_marking_threads(),
994 1, /* Minimum workers */
995 parallel_marking_threads(),
996 Threads::number_of_non_daemon_threads());
997 // Don't scale down "n_conc_workers" by scale_parallel_threads() because
998 // that scaling has already gone into "_max_parallel_marking_threads".
999 }
1000 assert(n_conc_workers > 0, "Always need at least 1");
1001 return n_conc_workers;
1002 }
1003 // If we are not running with any parallel GC threads we will not
1004 // have spawned any marking threads either. Hence the number of
1005 // concurrent workers should be 0.
1006 return 0;
1007 }
1008
1009 void ConcurrentMark::scanRootRegion(HeapRegion* hr, uint worker_id) {
1010 // Currently, only survivors can be root regions.
1011 assert(hr->next_top_at_mark_start() == hr->bottom(), "invariant");
1012 G1RootRegionScanClosure cl(_g1h, this, worker_id);
1013
1014 const uintx interval = PrefetchScanIntervalInBytes;
1015 HeapWord* curr = hr->bottom();
1016 const HeapWord* end = hr->top();
1017 while (curr < end) {
1018 Prefetch::read(curr, interval);
1019 oop obj = oop(curr);
1020 int size = obj->oop_iterate(&cl);
1021 assert(size == obj->size(), "sanity");
1022 curr += size;
1023 }
1024 }
1025
1026 class CMRootRegionScanTask : public AbstractGangTask {
1027 private:
1028 ConcurrentMark* _cm;
1029
1030 public:
1031 CMRootRegionScanTask(ConcurrentMark* cm) :
1032 AbstractGangTask("Root Region Scan"), _cm(cm) { }
1033
1034 void work(uint worker_id) {
1035 assert(Thread::current()->is_ConcurrentGC_thread(),
1036 "this should only be done by a conc GC thread");
1037
1038 CMRootRegions* root_regions = _cm->root_regions();
1039 HeapRegion* hr = root_regions->claim_next();
1040 while (hr != NULL) {
1041 _cm->scanRootRegion(hr, worker_id);
1042 hr = root_regions->claim_next();
1043 }
1044 }
1045 };
1046
1047 void ConcurrentMark::scanRootRegions() {
1048 // scan_in_progress() will have been set to true only if there was
1049 // at least one root region to scan. So, if it's false, we
1050 // should not attempt to do any further work.
1051 if (root_regions()->scan_in_progress()) {
1052 _parallel_marking_threads = calc_parallel_marking_threads();
1053 assert(parallel_marking_threads() <= max_parallel_marking_threads(),
1054 "Maximum number of marking threads exceeded");
1055 uint active_workers = MAX2(1U, parallel_marking_threads());
1056
1057 CMRootRegionScanTask task(this);
1058 if (parallel_marking_threads() > 0) {
1059 _parallel_workers->set_active_workers((int) active_workers);
1060 _parallel_workers->run_task(&task);
1061 } else {
1062 task.work(0);
1063 }
1064
1065 // It's possible that has_aborted() is true here without actually
1066 // aborting the survivor scan earlier. This is OK as it's
1067 // mainly used for sanity checking.
1068 root_regions()->scan_finished();
1069 }
1070 }
1071
1072 void ConcurrentMark::markFromRoots() {
1073 // we might be tempted to assert that:
1074 // assert(asynch == !SafepointSynchronize::is_at_safepoint(),
1075 // "inconsistent argument?");
1076 // However that wouldn't be right, because it's possible that
1077 // a safepoint is indeed in progress as a younger generation
1078 // stop-the-world GC happens even as we mark in this generation.
1079
1080 _restart_for_overflow = false;
1081 force_overflow_conc()->init();
1082
1083 // _g1h has _n_par_threads
1084 _parallel_marking_threads = calc_parallel_marking_threads();
1085 assert(parallel_marking_threads() <= max_parallel_marking_threads(),
1086 "Maximum number of marking threads exceeded");
1087
1088 uint active_workers = MAX2(1U, parallel_marking_threads());
1089
1090 // Parallel task terminator is set in "set_phase()"
1091 set_phase(active_workers, true /* concurrent */);
1092
1093 CMConcurrentMarkingTask markingTask(this, cmThread());
1094 if (parallel_marking_threads() > 0) {
1095 _parallel_workers->set_active_workers((int)active_workers);
1096 // Don't set _n_par_threads because it affects MT in proceess_strong_roots()
1097 // and the decisions on that MT processing is made elsewhere.
1098 assert(_parallel_workers->active_workers() > 0, "Should have been set");
1099 _parallel_workers->run_task(&markingTask);
1100 } else {
1101 markingTask.work(0);
1102 }
1103 print_stats();
1104 }
1105
1106 void ConcurrentMark::checkpointRootsFinal(bool clear_all_soft_refs) {
1107 // world is stopped at this checkpoint
1108 assert(SafepointSynchronize::is_at_safepoint(),
1109 "world should be stopped");
1110
1111 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1112
1113 // If a full collection has happened, we shouldn't do this.
1114 if (has_aborted()) {
1115 g1h->set_marking_complete(); // So bitmap clearing isn't confused
1116 return;
1117 }
1118
1119 SvcGCMarker sgcm(SvcGCMarker::OTHER);
1120
1121 if (VerifyDuringGC) {
1122 HandleMark hm; // handle scope
1123 gclog_or_tty->print(" VerifyDuringGC:(before)");
1124 Universe::heap()->prepare_for_verify();
1125 Universe::verify(/* silent */ false,
1126 /* option */ VerifyOption_G1UsePrevMarking);
1127 }
1128
1129 G1CollectorPolicy* g1p = g1h->g1_policy();
1130 g1p->record_concurrent_mark_remark_start();
1131
1132 double start = os::elapsedTime();
1133
1134 checkpointRootsFinalWork();
1135
1136 double mark_work_end = os::elapsedTime();
1137
1138 weakRefsWork(clear_all_soft_refs);
1139
1140 if (has_overflown()) {
1141 // Oops. We overflowed. Restart concurrent marking.
1142 _restart_for_overflow = true;
1143 // Clear the flag. We do not need it any more.
1144 clear_has_overflown();
1145 if (G1TraceMarkStackOverflow) {
1146 gclog_or_tty->print_cr("\nRemark led to restart for overflow.");
1147 }
1148 } else {
1149 // Aggregate the per-task counting data that we have accumulated
1150 // while marking.
1151 aggregate_count_data();
1152
1153 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set();
1154 // We're done with marking.
1155 // This is the end of the marking cycle, we're expected all
1156 // threads to have SATB queues with active set to true.
1157 satb_mq_set.set_active_all_threads(false, /* new active value */
1158 true /* expected_active */);
1159
1160 if (VerifyDuringGC) {
1161 HandleMark hm; // handle scope
1162 gclog_or_tty->print(" VerifyDuringGC:(after)");
1163 Universe::heap()->prepare_for_verify();
1164 Universe::verify(/* silent */ false,
1165 /* option */ VerifyOption_G1UseNextMarking);
1166 }
1167 assert(!restart_for_overflow(), "sanity");
1168 }
1169
1170 // Reset the marking state if marking completed
1171 if (!restart_for_overflow()) {
1172 set_non_marking_state();
1173 }
1174
1175 #if VERIFY_OBJS_PROCESSED
1176 _scan_obj_cl.objs_processed = 0;
1177 ThreadLocalObjQueue::objs_enqueued = 0;
1178 #endif
1179
1180 // Statistics
1181 double now = os::elapsedTime();
1182 _remark_mark_times.add((mark_work_end - start) * 1000.0);
1183 _remark_weak_ref_times.add((now - mark_work_end) * 1000.0);
1184 _remark_times.add((now - start) * 1000.0);
1185
1186 g1p->record_concurrent_mark_remark_end();
1187 }
1188
1189 // Base class of the closures that finalize and verify the
1190 // liveness counting data.
1191 class CMCountDataClosureBase: public HeapRegionClosure {
1192 protected:
1193 ConcurrentMark* _cm;
1194 BitMap* _region_bm;
1195 BitMap* _card_bm;
1196
1197 void set_card_bitmap_range(BitMap::idx_t start_idx, BitMap::idx_t last_idx) {
1198 assert(start_idx <= last_idx, "sanity");
1199
1200 // Set the inclusive bit range [start_idx, last_idx].
1201 // For small ranges (up to 8 cards) use a simple loop; otherwise
1202 // use par_at_put_range.
1203 if ((last_idx - start_idx) < 8) {
1204 for (BitMap::idx_t i = start_idx; i <= last_idx; i += 1) {
1205 _card_bm->par_set_bit(i);
1206 }
1207 } else {
1208 assert(last_idx < _card_bm->size(), "sanity");
1209 // Note BitMap::par_at_put_range() is exclusive.
1210 _card_bm->par_at_put_range(start_idx, last_idx+1, true);
1211 }
1212 }
1213
1214 // It takes a region that's not empty (i.e., it has at least one
1215 // live object in it and sets its corresponding bit on the region
1216 // bitmap to 1. If the region is "starts humongous" it will also set
1217 // to 1 the bits on the region bitmap that correspond to its
1218 // associated "continues humongous" regions.
1219 void set_bit_for_region(HeapRegion* hr) {
1220 assert(!hr->continuesHumongous(), "should have filtered those out");
1221
1222 BitMap::idx_t index = (BitMap::idx_t) hr->hrs_index();
1223 if (!hr->startsHumongous()) {
1224 // Normal (non-humongous) case: just set the bit.
1225 _region_bm->par_at_put(index, true);
1226 } else {
1227 // Starts humongous case: calculate how many regions are part of
1228 // this humongous region and then set the bit range.
1229 BitMap::idx_t end_index = (BitMap::idx_t) hr->last_hc_index();
1230 _region_bm->par_at_put_range(index, end_index, true);
1231 }
1232 }
1233
1234 public:
1235 CMCountDataClosureBase(ConcurrentMark *cm,
1236 BitMap* region_bm, BitMap* card_bm):
1237 _cm(cm), _region_bm(region_bm), _card_bm(card_bm) { }
1238 };
1239
1240 // Closure that calculates the # live objects per region. Used
1241 // for verification purposes during the cleanup pause.
1242 class CalcLiveObjectsClosure: public CMCountDataClosureBase {
1243 CMBitMapRO* _bm;
1244 size_t _region_marked_bytes;
1245
1246 public:
1247 CalcLiveObjectsClosure(CMBitMapRO *bm, ConcurrentMark *cm,
1248 BitMap* region_bm, BitMap* card_bm) :
1249 CMCountDataClosureBase(cm, region_bm, card_bm),
1250 _bm(bm), _region_marked_bytes(0) { }
1251
1252 bool doHeapRegion(HeapRegion* hr) {
1253
1254 if (hr->continuesHumongous()) {
1255 // We will ignore these here and process them when their
1256 // associated "starts humongous" region is processed (see
1257 // set_bit_for_heap_region()). Note that we cannot rely on their
1258 // associated "starts humongous" region to have their bit set to
1259 // 1 since, due to the region chunking in the parallel region
1260 // iteration, a "continues humongous" region might be visited
1261 // before its associated "starts humongous".
1262 return false;
1263 }
1264
1265 HeapWord* nextTop = hr->next_top_at_mark_start();
1266 HeapWord* start = hr->bottom();
1267
1268 assert(start <= hr->end() && start <= nextTop && nextTop <= hr->end(),
1269 err_msg("Preconditions not met - "
1270 "start: "PTR_FORMAT", nextTop: "PTR_FORMAT", end: "PTR_FORMAT,
1271 start, nextTop, hr->end()));
1272
1273 // Find the first marked object at or after "start".
1274 start = _bm->getNextMarkedWordAddress(start, nextTop);
1275
1276 size_t marked_bytes = 0;
1277
1278 while (start < nextTop) {
1279 oop obj = oop(start);
1280 int obj_sz = obj->size();
1281 HeapWord* obj_last = start + obj_sz - 1;
1282
1283 BitMap::idx_t start_idx = _cm->card_bitmap_index_for(start);
1284 BitMap::idx_t last_idx = _cm->card_bitmap_index_for(obj_last);
1285
1286 // Set the bits in the card BM for this object (inclusive).
1287 set_card_bitmap_range(start_idx, last_idx);
1288
1289 // Add the size of this object to the number of marked bytes.
1290 marked_bytes += (size_t)obj_sz * HeapWordSize;
1291
1292 // Find the next marked object after this one.
1293 start = _bm->getNextMarkedWordAddress(obj_last + 1, nextTop);
1294 }
1295
1296 // Mark the allocated-since-marking portion...
1297 HeapWord* top = hr->top();
1298 if (nextTop < top) {
1299 BitMap::idx_t start_idx = _cm->card_bitmap_index_for(nextTop);
1300 BitMap::idx_t last_idx = _cm->card_bitmap_index_for(top - 1);
1301
1302 set_card_bitmap_range(start_idx, last_idx);
1303
1304 // This definitely means the region has live objects.
1305 set_bit_for_region(hr);
1306 }
1307
1308 // Update the live region bitmap.
1309 if (marked_bytes > 0) {
1310 set_bit_for_region(hr);
1311 }
1312
1313 // Set the marked bytes for the current region so that
1314 // it can be queried by a calling verificiation routine
1315 _region_marked_bytes = marked_bytes;
1316
1317 return false;
1318 }
1319
1320 size_t region_marked_bytes() const { return _region_marked_bytes; }
1321 };
1322
1323 // Heap region closure used for verifying the counting data
1324 // that was accumulated concurrently and aggregated during
1325 // the remark pause. This closure is applied to the heap
1326 // regions during the STW cleanup pause.
1327
1328 class VerifyLiveObjectDataHRClosure: public HeapRegionClosure {
1329 ConcurrentMark* _cm;
1330 CalcLiveObjectsClosure _calc_cl;
1331 BitMap* _region_bm; // Region BM to be verified
1332 BitMap* _card_bm; // Card BM to be verified
1333 bool _verbose; // verbose output?
1334
1335 BitMap* _exp_region_bm; // Expected Region BM values
1336 BitMap* _exp_card_bm; // Expected card BM values
1337
1338 int _failures;
1339
1340 public:
1341 VerifyLiveObjectDataHRClosure(ConcurrentMark* cm,
1342 BitMap* region_bm,
1343 BitMap* card_bm,
1344 BitMap* exp_region_bm,
1345 BitMap* exp_card_bm,
1346 bool verbose) :
1347 _cm(cm),
1348 _calc_cl(_cm->nextMarkBitMap(), _cm, exp_region_bm, exp_card_bm),
1349 _region_bm(region_bm), _card_bm(card_bm), _verbose(verbose),
1350 _exp_region_bm(exp_region_bm), _exp_card_bm(exp_card_bm),
1351 _failures(0) { }
1352
1353 int failures() const { return _failures; }
1354
1355 bool doHeapRegion(HeapRegion* hr) {
1356 if (hr->continuesHumongous()) {
1357 // We will ignore these here and process them when their
1358 // associated "starts humongous" region is processed (see
1359 // set_bit_for_heap_region()). Note that we cannot rely on their
1360 // associated "starts humongous" region to have their bit set to
1361 // 1 since, due to the region chunking in the parallel region
1362 // iteration, a "continues humongous" region might be visited
1363 // before its associated "starts humongous".
1364 return false;
1365 }
1366
1367 int failures = 0;
1368
1369 // Call the CalcLiveObjectsClosure to walk the marking bitmap for
1370 // this region and set the corresponding bits in the expected region
1371 // and card bitmaps.
1372 bool res = _calc_cl.doHeapRegion(hr);
1373 assert(res == false, "should be continuing");
1374
1375 MutexLockerEx x((_verbose ? ParGCRareEvent_lock : NULL),
1376 Mutex::_no_safepoint_check_flag);
1377
1378 // Verify the marked bytes for this region.
1379 size_t exp_marked_bytes = _calc_cl.region_marked_bytes();
1380 size_t act_marked_bytes = hr->next_marked_bytes();
1381
1382 // We're not OK if expected marked bytes > actual marked bytes. It means
1383 // we have missed accounting some objects during the actual marking.
1384 if (exp_marked_bytes > act_marked_bytes) {
1385 if (_verbose) {
1386 gclog_or_tty->print_cr("Region %u: marked bytes mismatch: "
1387 "expected: " SIZE_FORMAT ", actual: " SIZE_FORMAT,
1388 hr->hrs_index(), exp_marked_bytes, act_marked_bytes);
1389 }
1390 failures += 1;
1391 }
1392
1393 // Verify the bit, for this region, in the actual and expected
1394 // (which was just calculated) region bit maps.
1395 // We're not OK if the bit in the calculated expected region
1396 // bitmap is set and the bit in the actual region bitmap is not.
1397 BitMap::idx_t index = (BitMap::idx_t) hr->hrs_index();
1398
1399 bool expected = _exp_region_bm->at(index);
1400 bool actual = _region_bm->at(index);
1401 if (expected && !actual) {
1402 if (_verbose) {
1403 gclog_or_tty->print_cr("Region %u: region bitmap mismatch: "
1404 "expected: %s, actual: %s",
1405 hr->hrs_index(),
1406 BOOL_TO_STR(expected), BOOL_TO_STR(actual));
1407 }
1408 failures += 1;
1409 }
1410
1411 // Verify that the card bit maps for the cards spanned by the current
1412 // region match. We have an error if we have a set bit in the expected
1413 // bit map and the corresponding bit in the actual bitmap is not set.
1414
1415 BitMap::idx_t start_idx = _cm->card_bitmap_index_for(hr->bottom());
1416 BitMap::idx_t end_idx = _cm->card_bitmap_index_for(hr->top());
1417
1418 for (BitMap::idx_t i = start_idx; i < end_idx; i+=1) {
1419 expected = _exp_card_bm->at(i);
1420 actual = _card_bm->at(i);
1421
1422 if (expected && !actual) {
1423 if (_verbose) {
1424 gclog_or_tty->print_cr("Region %u: card bitmap mismatch at " SIZE_FORMAT ": "
1425 "expected: %s, actual: %s",
1426 hr->hrs_index(), i,
1427 BOOL_TO_STR(expected), BOOL_TO_STR(actual));
1428 }
1429 failures += 1;
1430 }
1431 }
1432
1433 if (failures > 0 && _verbose) {
1434 gclog_or_tty->print_cr("Region " HR_FORMAT ", ntams: " PTR_FORMAT ", "
1435 "marked_bytes: calc/actual " SIZE_FORMAT "/" SIZE_FORMAT,
1436 HR_FORMAT_PARAMS(hr), hr->next_top_at_mark_start(),
1437 _calc_cl.region_marked_bytes(), hr->next_marked_bytes());
1438 }
1439
1440 _failures += failures;
1441
1442 // We could stop iteration over the heap when we
1443 // find the first violating region by returning true.
1444 return false;
1445 }
1446 };
1447
1448
1449 class G1ParVerifyFinalCountTask: public AbstractGangTask {
1450 protected:
1451 G1CollectedHeap* _g1h;
1452 ConcurrentMark* _cm;
1453 BitMap* _actual_region_bm;
1454 BitMap* _actual_card_bm;
1455
1456 uint _n_workers;
1457
1458 BitMap* _expected_region_bm;
1459 BitMap* _expected_card_bm;
1460
1461 int _failures;
1462 bool _verbose;
1463
1464 public:
1465 G1ParVerifyFinalCountTask(G1CollectedHeap* g1h,
1466 BitMap* region_bm, BitMap* card_bm,
1467 BitMap* expected_region_bm, BitMap* expected_card_bm)
1468 : AbstractGangTask("G1 verify final counting"),
1469 _g1h(g1h), _cm(_g1h->concurrent_mark()),
1470 _actual_region_bm(region_bm), _actual_card_bm(card_bm),
1471 _expected_region_bm(expected_region_bm), _expected_card_bm(expected_card_bm),
1472 _failures(0), _verbose(false),
1473 _n_workers(0) {
1474 assert(VerifyDuringGC, "don't call this otherwise");
1475
1476 // Use the value already set as the number of active threads
1477 // in the call to run_task().
1478 if (G1CollectedHeap::use_parallel_gc_threads()) {
1479 assert( _g1h->workers()->active_workers() > 0,
1480 "Should have been previously set");
1481 _n_workers = _g1h->workers()->active_workers();
1482 } else {
1483 _n_workers = 1;
1484 }
1485
1486 assert(_expected_card_bm->size() == _actual_card_bm->size(), "sanity");
1487 assert(_expected_region_bm->size() == _actual_region_bm->size(), "sanity");
1488
1489 _verbose = _cm->verbose_medium();
1490 }
1491
1492 void work(uint worker_id) {
1493 assert(worker_id < _n_workers, "invariant");
1494
1495 VerifyLiveObjectDataHRClosure verify_cl(_cm,
1496 _actual_region_bm, _actual_card_bm,
1497 _expected_region_bm,
1498 _expected_card_bm,
1499 _verbose);
1500
1501 if (G1CollectedHeap::use_parallel_gc_threads()) {
1502 _g1h->heap_region_par_iterate_chunked(&verify_cl,
1503 worker_id,
1504 _n_workers,
1505 HeapRegion::VerifyCountClaimValue);
1506 } else {
1507 _g1h->heap_region_iterate(&verify_cl);
1508 }
1509
1510 Atomic::add(verify_cl.failures(), &_failures);
1511 }
1512
1513 int failures() const { return _failures; }
1514 };
1515
1516 // Closure that finalizes the liveness counting data.
1517 // Used during the cleanup pause.
1518 // Sets the bits corresponding to the interval [NTAMS, top]
1519 // (which contains the implicitly live objects) in the
1520 // card liveness bitmap. Also sets the bit for each region,
1521 // containing live data, in the region liveness bitmap.
1522
1523 class FinalCountDataUpdateClosure: public CMCountDataClosureBase {
1524 public:
1525 FinalCountDataUpdateClosure(ConcurrentMark* cm,
1526 BitMap* region_bm,
1527 BitMap* card_bm) :
1528 CMCountDataClosureBase(cm, region_bm, card_bm) { }
1529
1530 bool doHeapRegion(HeapRegion* hr) {
1531
1532 if (hr->continuesHumongous()) {
1533 // We will ignore these here and process them when their
1534 // associated "starts humongous" region is processed (see
1535 // set_bit_for_heap_region()). Note that we cannot rely on their
1536 // associated "starts humongous" region to have their bit set to
1537 // 1 since, due to the region chunking in the parallel region
1538 // iteration, a "continues humongous" region might be visited
1539 // before its associated "starts humongous".
1540 return false;
1541 }
1542
1543 HeapWord* ntams = hr->next_top_at_mark_start();
1544 HeapWord* top = hr->top();
1545
1546 assert(hr->bottom() <= ntams && ntams <= hr->end(), "Preconditions.");
1547
1548 // Mark the allocated-since-marking portion...
1549 if (ntams < top) {
1550 // This definitely means the region has live objects.
1551 set_bit_for_region(hr);
1552 }
1553
1554 // Now set the bits for [ntams, top]
1555 BitMap::idx_t start_idx = _cm->card_bitmap_index_for(ntams);
1556 BitMap::idx_t last_idx = _cm->card_bitmap_index_for(top);
1557 set_card_bitmap_range(start_idx, last_idx);
1558
1559 // Set the bit for the region if it contains live data
1560 if (hr->next_marked_bytes() > 0) {
1561 set_bit_for_region(hr);
1562 }
1563
1564 return false;
1565 }
1566 };
1567
1568 class G1ParFinalCountTask: public AbstractGangTask {
1569 protected:
1570 G1CollectedHeap* _g1h;
1571 ConcurrentMark* _cm;
1572 BitMap* _actual_region_bm;
1573 BitMap* _actual_card_bm;
1574
1575 uint _n_workers;
1576
1577 public:
1578 G1ParFinalCountTask(G1CollectedHeap* g1h, BitMap* region_bm, BitMap* card_bm)
1579 : AbstractGangTask("G1 final counting"),
1580 _g1h(g1h), _cm(_g1h->concurrent_mark()),
1581 _actual_region_bm(region_bm), _actual_card_bm(card_bm),
1582 _n_workers(0) {
1583 // Use the value already set as the number of active threads
1584 // in the call to run_task().
1585 if (G1CollectedHeap::use_parallel_gc_threads()) {
1586 assert( _g1h->workers()->active_workers() > 0,
1587 "Should have been previously set");
1588 _n_workers = _g1h->workers()->active_workers();
1589 } else {
1590 _n_workers = 1;
1591 }
1592 }
1593
1594 void work(uint worker_id) {
1595 assert(worker_id < _n_workers, "invariant");
1596
1597 FinalCountDataUpdateClosure final_update_cl(_cm,
1598 _actual_region_bm,
1599 _actual_card_bm);
1600
1601 if (G1CollectedHeap::use_parallel_gc_threads()) {
1602 _g1h->heap_region_par_iterate_chunked(&final_update_cl,
1603 worker_id,
1604 _n_workers,
1605 HeapRegion::FinalCountClaimValue);
1606 } else {
1607 _g1h->heap_region_iterate(&final_update_cl);
1608 }
1609 }
1610 };
1611
1612 class G1ParNoteEndTask;
1613
1614 class G1NoteEndOfConcMarkClosure : public HeapRegionClosure {
1615 G1CollectedHeap* _g1;
1616 int _worker_num;
1617 size_t _max_live_bytes;
1618 uint _regions_claimed;
1619 size_t _freed_bytes;
1620 FreeRegionList* _local_cleanup_list;
1621 OldRegionSet* _old_proxy_set;
1622 HumongousRegionSet* _humongous_proxy_set;
1623 HRRSCleanupTask* _hrrs_cleanup_task;
1624 double _claimed_region_time;
1625 double _max_region_time;
1626
1627 public:
1628 G1NoteEndOfConcMarkClosure(G1CollectedHeap* g1,
1629 int worker_num,
1630 FreeRegionList* local_cleanup_list,
1631 OldRegionSet* old_proxy_set,
1632 HumongousRegionSet* humongous_proxy_set,
1633 HRRSCleanupTask* hrrs_cleanup_task) :
1634 _g1(g1), _worker_num(worker_num),
1635 _max_live_bytes(0), _regions_claimed(0),
1636 _freed_bytes(0),
1637 _claimed_region_time(0.0), _max_region_time(0.0),
1638 _local_cleanup_list(local_cleanup_list),
1639 _old_proxy_set(old_proxy_set),
1640 _humongous_proxy_set(humongous_proxy_set),
1641 _hrrs_cleanup_task(hrrs_cleanup_task) { }
1642
1643 size_t freed_bytes() { return _freed_bytes; }
1644
1645 bool doHeapRegion(HeapRegion *hr) {
1646 if (hr->continuesHumongous()) {
1647 return false;
1648 }
1649 // We use a claim value of zero here because all regions
1650 // were claimed with value 1 in the FinalCount task.
1651 _g1->reset_gc_time_stamps(hr);
1652 double start = os::elapsedTime();
1653 _regions_claimed++;
1654 hr->note_end_of_marking();
1655 _max_live_bytes += hr->max_live_bytes();
1656 _g1->free_region_if_empty(hr,
1657 &_freed_bytes,
1658 _local_cleanup_list,
1659 _old_proxy_set,
1660 _humongous_proxy_set,
1661 _hrrs_cleanup_task,
1662 true /* par */);
1663 double region_time = (os::elapsedTime() - start);
1664 _claimed_region_time += region_time;
1665 if (region_time > _max_region_time) {
1666 _max_region_time = region_time;
1667 }
1668 return false;
1669 }
1670
1671 size_t max_live_bytes() { return _max_live_bytes; }
1672 uint regions_claimed() { return _regions_claimed; }
1673 double claimed_region_time_sec() { return _claimed_region_time; }
1674 double max_region_time_sec() { return _max_region_time; }
1675 };
1676
1677 class G1ParNoteEndTask: public AbstractGangTask {
1678 friend class G1NoteEndOfConcMarkClosure;
1679
1680 protected:
1681 G1CollectedHeap* _g1h;
1682 size_t _max_live_bytes;
1683 size_t _freed_bytes;
1684 FreeRegionList* _cleanup_list;
1685
1686 public:
1687 G1ParNoteEndTask(G1CollectedHeap* g1h,
1688 FreeRegionList* cleanup_list) :
1689 AbstractGangTask("G1 note end"), _g1h(g1h),
1690 _max_live_bytes(0), _freed_bytes(0), _cleanup_list(cleanup_list) { }
1691
1692 void work(uint worker_id) {
1693 double start = os::elapsedTime();
1694 FreeRegionList local_cleanup_list("Local Cleanup List");
1695 OldRegionSet old_proxy_set("Local Cleanup Old Proxy Set");
1696 HumongousRegionSet humongous_proxy_set("Local Cleanup Humongous Proxy Set");
1697 HRRSCleanupTask hrrs_cleanup_task;
1698 G1NoteEndOfConcMarkClosure g1_note_end(_g1h, worker_id, &local_cleanup_list,
1699 &old_proxy_set,
1700 &humongous_proxy_set,
1701 &hrrs_cleanup_task);
1702 if (G1CollectedHeap::use_parallel_gc_threads()) {
1703 _g1h->heap_region_par_iterate_chunked(&g1_note_end, worker_id,
1704 _g1h->workers()->active_workers(),
1705 HeapRegion::NoteEndClaimValue);
1706 } else {
1707 _g1h->heap_region_iterate(&g1_note_end);
1708 }
1709 assert(g1_note_end.complete(), "Shouldn't have yielded!");
1710
1711 // Now update the lists
1712 _g1h->update_sets_after_freeing_regions(g1_note_end.freed_bytes(),
1713 NULL /* free_list */,
1714 &old_proxy_set,
1715 &humongous_proxy_set,
1716 true /* par */);
1717 {
1718 MutexLockerEx x(ParGCRareEvent_lock, Mutex::_no_safepoint_check_flag);
1719 _max_live_bytes += g1_note_end.max_live_bytes();
1720 _freed_bytes += g1_note_end.freed_bytes();
1721
1722 // If we iterate over the global cleanup list at the end of
1723 // cleanup to do this printing we will not guarantee to only
1724 // generate output for the newly-reclaimed regions (the list
1725 // might not be empty at the beginning of cleanup; we might
1726 // still be working on its previous contents). So we do the
1727 // printing here, before we append the new regions to the global
1728 // cleanup list.
1729
1730 G1HRPrinter* hr_printer = _g1h->hr_printer();
1731 if (hr_printer->is_active()) {
1732 HeapRegionLinkedListIterator iter(&local_cleanup_list);
1733 while (iter.more_available()) {
1734 HeapRegion* hr = iter.get_next();
1735 hr_printer->cleanup(hr);
1736 }
1737 }
1738
1739 _cleanup_list->add_as_tail(&local_cleanup_list);
1740 assert(local_cleanup_list.is_empty(), "post-condition");
1741
1742 HeapRegionRemSet::finish_cleanup_task(&hrrs_cleanup_task);
1743 }
1744 }
1745 size_t max_live_bytes() { return _max_live_bytes; }
1746 size_t freed_bytes() { return _freed_bytes; }
1747 };
1748
1749 class G1ParScrubRemSetTask: public AbstractGangTask {
1750 protected:
1751 G1RemSet* _g1rs;
1752 BitMap* _region_bm;
1753 BitMap* _card_bm;
1754 public:
1755 G1ParScrubRemSetTask(G1CollectedHeap* g1h,
1756 BitMap* region_bm, BitMap* card_bm) :
1757 AbstractGangTask("G1 ScrubRS"), _g1rs(g1h->g1_rem_set()),
1758 _region_bm(region_bm), _card_bm(card_bm) { }
1759
1760 void work(uint worker_id) {
1761 if (G1CollectedHeap::use_parallel_gc_threads()) {
1762 _g1rs->scrub_par(_region_bm, _card_bm, worker_id,
1763 HeapRegion::ScrubRemSetClaimValue);
1764 } else {
1765 _g1rs->scrub(_region_bm, _card_bm);
1766 }
1767 }
1768
1769 };
1770
1771 void ConcurrentMark::cleanup() {
1772 // world is stopped at this checkpoint
1773 assert(SafepointSynchronize::is_at_safepoint(),
1774 "world should be stopped");
1775 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1776
1777 // If a full collection has happened, we shouldn't do this.
1778 if (has_aborted()) {
1779 g1h->set_marking_complete(); // So bitmap clearing isn't confused
1780 return;
1781 }
1782
1783 HRSPhaseSetter x(HRSPhaseCleanup);
1784 g1h->verify_region_sets_optional();
1785
1786 if (VerifyDuringGC) {
1787 HandleMark hm; // handle scope
1788 gclog_or_tty->print(" VerifyDuringGC:(before)");
1789 Universe::heap()->prepare_for_verify();
1790 Universe::verify(/* silent */ false,
1791 /* option */ VerifyOption_G1UsePrevMarking);
1792 }
1793
1794 G1CollectorPolicy* g1p = G1CollectedHeap::heap()->g1_policy();
1795 g1p->record_concurrent_mark_cleanup_start();
1796
1797 double start = os::elapsedTime();
1798
1799 HeapRegionRemSet::reset_for_cleanup_tasks();
1800
1801 uint n_workers;
1802
1803 // Do counting once more with the world stopped for good measure.
1804 G1ParFinalCountTask g1_par_count_task(g1h, &_region_bm, &_card_bm);
1805
1806 if (G1CollectedHeap::use_parallel_gc_threads()) {
1807 assert(g1h->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
1808 "sanity check");
1809
1810 g1h->set_par_threads();
1811 n_workers = g1h->n_par_threads();
1812 assert(g1h->n_par_threads() == n_workers,
1813 "Should not have been reset");
1814 g1h->workers()->run_task(&g1_par_count_task);
1815 // Done with the parallel phase so reset to 0.
1816 g1h->set_par_threads(0);
1817
1818 assert(g1h->check_heap_region_claim_values(HeapRegion::FinalCountClaimValue),
1819 "sanity check");
1820 } else {
1821 n_workers = 1;
1822 g1_par_count_task.work(0);
1823 }
1824
1825 if (VerifyDuringGC) {
1826 // Verify that the counting data accumulated during marking matches
1827 // that calculated by walking the marking bitmap.
1828
1829 // Bitmaps to hold expected values
1830 BitMap expected_region_bm(_region_bm.size(), false);
1831 BitMap expected_card_bm(_card_bm.size(), false);
1832
1833 G1ParVerifyFinalCountTask g1_par_verify_task(g1h,
1834 &_region_bm,
1835 &_card_bm,
1836 &expected_region_bm,
1837 &expected_card_bm);
1838
1839 if (G1CollectedHeap::use_parallel_gc_threads()) {
1840 g1h->set_par_threads((int)n_workers);
1841 g1h->workers()->run_task(&g1_par_verify_task);
1842 // Done with the parallel phase so reset to 0.
1843 g1h->set_par_threads(0);
1844
1845 assert(g1h->check_heap_region_claim_values(HeapRegion::VerifyCountClaimValue),
1846 "sanity check");
1847 } else {
1848 g1_par_verify_task.work(0);
1849 }
1850
1851 guarantee(g1_par_verify_task.failures() == 0, "Unexpected accounting failures");
1852 }
1853
1854 size_t start_used_bytes = g1h->used();
1855 g1h->set_marking_complete();
1856
1857 double count_end = os::elapsedTime();
1858 double this_final_counting_time = (count_end - start);
1859 _total_counting_time += this_final_counting_time;
1860
1861 if (G1PrintRegionLivenessInfo) {
1862 G1PrintRegionLivenessInfoClosure cl(gclog_or_tty, "Post-Marking");
1863 _g1h->heap_region_iterate(&cl);
1864 }
1865
1866 // Install newly created mark bitMap as "prev".
1867 swapMarkBitMaps();
1868
1869 g1h->reset_gc_time_stamp();
1870
1871 // Note end of marking in all heap regions.
1872 G1ParNoteEndTask g1_par_note_end_task(g1h, &_cleanup_list);
1873 if (G1CollectedHeap::use_parallel_gc_threads()) {
1874 g1h->set_par_threads((int)n_workers);
1875 g1h->workers()->run_task(&g1_par_note_end_task);
1876 g1h->set_par_threads(0);
1877
1878 assert(g1h->check_heap_region_claim_values(HeapRegion::NoteEndClaimValue),
1879 "sanity check");
1880 } else {
1881 g1_par_note_end_task.work(0);
1882 }
1883 g1h->check_gc_time_stamps();
1884
1885 if (!cleanup_list_is_empty()) {
1886 // The cleanup list is not empty, so we'll have to process it
1887 // concurrently. Notify anyone else that might be wanting free
1888 // regions that there will be more free regions coming soon.
1889 g1h->set_free_regions_coming();
1890 }
1891
1892 // call below, since it affects the metric by which we sort the heap
1893 // regions.
1894 if (G1ScrubRemSets) {
1895 double rs_scrub_start = os::elapsedTime();
1896 G1ParScrubRemSetTask g1_par_scrub_rs_task(g1h, &_region_bm, &_card_bm);
1897 if (G1CollectedHeap::use_parallel_gc_threads()) {
1898 g1h->set_par_threads((int)n_workers);
1899 g1h->workers()->run_task(&g1_par_scrub_rs_task);
1900 g1h->set_par_threads(0);
1901
1902 assert(g1h->check_heap_region_claim_values(
1903 HeapRegion::ScrubRemSetClaimValue),
1904 "sanity check");
1905 } else {
1906 g1_par_scrub_rs_task.work(0);
1907 }
1908
1909 double rs_scrub_end = os::elapsedTime();
1910 double this_rs_scrub_time = (rs_scrub_end - rs_scrub_start);
1911 _total_rs_scrub_time += this_rs_scrub_time;
1912 }
1913
1914 // this will also free any regions totally full of garbage objects,
1915 // and sort the regions.
1916 g1h->g1_policy()->record_concurrent_mark_cleanup_end((int)n_workers);
1917
1918 // Statistics.
1919 double end = os::elapsedTime();
1920 _cleanup_times.add((end - start) * 1000.0);
1921
1922 if (G1Log::fine()) {
1923 g1h->print_size_transition(gclog_or_tty,
1924 start_used_bytes,
1925 g1h->used(),
1926 g1h->capacity());
1927 }
1928
1929 // Clean up will have freed any regions completely full of garbage.
1930 // Update the soft reference policy with the new heap occupancy.
1931 Universe::update_heap_info_at_gc();
1932
1933 // We need to make this be a "collection" so any collection pause that
1934 // races with it goes around and waits for completeCleanup to finish.
1935 g1h->increment_total_collections();
1936
1937 // We reclaimed old regions so we should calculate the sizes to make
1938 // sure we update the old gen/space data.
1939 g1h->g1mm()->update_sizes();
1940
1941 if (VerifyDuringGC) {
1942 HandleMark hm; // handle scope
1943 gclog_or_tty->print(" VerifyDuringGC:(after)");
1944 Universe::heap()->prepare_for_verify();
1945 Universe::verify(/* silent */ false,
1946 /* option */ VerifyOption_G1UsePrevMarking);
1947 }
1948
1949 g1h->verify_region_sets_optional();
1950 }
1951
1952 void ConcurrentMark::completeCleanup() {
1953 if (has_aborted()) return;
1954
1955 G1CollectedHeap* g1h = G1CollectedHeap::heap();
1956
1957 _cleanup_list.verify_optional();
1958 FreeRegionList tmp_free_list("Tmp Free List");
1959
1960 if (G1ConcRegionFreeingVerbose) {
1961 gclog_or_tty->print_cr("G1ConcRegionFreeing [complete cleanup] : "
1962 "cleanup list has %u entries",
1963 _cleanup_list.length());
1964 }
1965
1966 // Noone else should be accessing the _cleanup_list at this point,
1967 // so it's not necessary to take any locks
1968 while (!_cleanup_list.is_empty()) {
1969 HeapRegion* hr = _cleanup_list.remove_head();
1970 assert(hr != NULL, "the list was not empty");
1971 hr->par_clear();
1972 tmp_free_list.add_as_tail(hr);
1973
1974 // Instead of adding one region at a time to the secondary_free_list,
1975 // we accumulate them in the local list and move them a few at a
1976 // time. This also cuts down on the number of notify_all() calls
1977 // we do during this process. We'll also append the local list when
1978 // _cleanup_list is empty (which means we just removed the last
1979 // region from the _cleanup_list).
1980 if ((tmp_free_list.length() % G1SecondaryFreeListAppendLength == 0) ||
1981 _cleanup_list.is_empty()) {
1982 if (G1ConcRegionFreeingVerbose) {
1983 gclog_or_tty->print_cr("G1ConcRegionFreeing [complete cleanup] : "
1984 "appending %u entries to the secondary_free_list, "
1985 "cleanup list still has %u entries",
1986 tmp_free_list.length(),
1987 _cleanup_list.length());
1988 }
1989
1990 {
1991 MutexLockerEx x(SecondaryFreeList_lock, Mutex::_no_safepoint_check_flag);
1992 g1h->secondary_free_list_add_as_tail(&tmp_free_list);
1993 SecondaryFreeList_lock->notify_all();
1994 }
1995
1996 if (G1StressConcRegionFreeing) {
1997 for (uintx i = 0; i < G1StressConcRegionFreeingDelayMillis; ++i) {
1998 os::sleep(Thread::current(), (jlong) 1, false);
1999 }
2000 }
2001 }
2002 }
2003 assert(tmp_free_list.is_empty(), "post-condition");
2004 }
2005
2006 // Support closures for reference procssing in G1
2007
2008 bool G1CMIsAliveClosure::do_object_b(oop obj) {
2009 HeapWord* addr = (HeapWord*)obj;
2010 return addr != NULL &&
2011 (!_g1->is_in_g1_reserved(addr) || !_g1->is_obj_ill(obj));
2012 }
2013
2014 class G1CMKeepAliveClosure: public OopClosure {
2015 G1CollectedHeap* _g1;
2016 ConcurrentMark* _cm;
2017 public:
2018 G1CMKeepAliveClosure(G1CollectedHeap* g1, ConcurrentMark* cm) :
2019 _g1(g1), _cm(cm) {
2020 assert(Thread::current()->is_VM_thread(), "otherwise fix worker id");
2021 }
2022
2023 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
2024 virtual void do_oop( oop* p) { do_oop_work(p); }
2025
2026 template <class T> void do_oop_work(T* p) {
2027 oop obj = oopDesc::load_decode_heap_oop(p);
2028 HeapWord* addr = (HeapWord*)obj;
2029
2030 if (_cm->verbose_high()) {
2031 gclog_or_tty->print_cr("\t[0] we're looking at location "
2032 "*"PTR_FORMAT" = "PTR_FORMAT,
2033 p, (void*) obj);
2034 }
2035
2036 if (_g1->is_in_g1_reserved(addr) && _g1->is_obj_ill(obj)) {
2037 _cm->mark_and_count(obj);
2038 _cm->mark_stack_push(obj);
2039 }
2040 }
2041 };
2042
2043 class G1CMDrainMarkingStackClosure: public VoidClosure {
2044 ConcurrentMark* _cm;
2045 CMMarkStack* _markStack;
2046 G1CMKeepAliveClosure* _oopClosure;
2047 public:
2048 G1CMDrainMarkingStackClosure(ConcurrentMark* cm, CMMarkStack* markStack,
2049 G1CMKeepAliveClosure* oopClosure) :
2050 _cm(cm),
2051 _markStack(markStack),
2052 _oopClosure(oopClosure) { }
2053
2054 void do_void() {
2055 _markStack->drain((OopClosure*)_oopClosure, _cm->nextMarkBitMap(), false);
2056 }
2057 };
2058
2059 // 'Keep Alive' closure used by parallel reference processing.
2060 // An instance of this closure is used in the parallel reference processing
2061 // code rather than an instance of G1CMKeepAliveClosure. We could have used
2062 // the G1CMKeepAliveClosure as it is MT-safe. Also reference objects are
2063 // placed on to discovered ref lists once so we can mark and push with no
2064 // need to check whether the object has already been marked. Using the
2065 // G1CMKeepAliveClosure would mean, however, having all the worker threads
2066 // operating on the global mark stack. This means that an individual
2067 // worker would be doing lock-free pushes while it processes its own
2068 // discovered ref list followed by drain call. If the discovered ref lists
2069 // are unbalanced then this could cause interference with the other
2070 // workers. Using a CMTask (and its embedded local data structures)
2071 // avoids that potential interference.
2072 class G1CMParKeepAliveAndDrainClosure: public OopClosure {
2073 ConcurrentMark* _cm;
2074 CMTask* _task;
2075 int _ref_counter_limit;
2076 int _ref_counter;
2077 public:
2078 G1CMParKeepAliveAndDrainClosure(ConcurrentMark* cm, CMTask* task) :
2079 _cm(cm), _task(task),
2080 _ref_counter_limit(G1RefProcDrainInterval) {
2081 assert(_ref_counter_limit > 0, "sanity");
2082 _ref_counter = _ref_counter_limit;
2083 }
2084
2085 virtual void do_oop(narrowOop* p) { do_oop_work(p); }
2086 virtual void do_oop( oop* p) { do_oop_work(p); }
2087
2088 template <class T> void do_oop_work(T* p) {
2089 if (!_cm->has_overflown()) {
2090 oop obj = oopDesc::load_decode_heap_oop(p);
2091 if (_cm->verbose_high()) {
2092 gclog_or_tty->print_cr("\t[%d] we're looking at location "
2093 "*"PTR_FORMAT" = "PTR_FORMAT,
2094 _task->task_id(), p, (void*) obj);
2095 }
2096
2097 _task->deal_with_reference(obj);
2098 _ref_counter--;
2099
2100 if (_ref_counter == 0) {
2101 // We have dealt with _ref_counter_limit references, pushing them and objects
2102 // reachable from them on to the local stack (and possibly the global stack).
2103 // Call do_marking_step() to process these entries. We call the routine in a
2104 // loop, which we'll exit if there's nothing more to do (i.e. we're done
2105 // with the entries that we've pushed as a result of the deal_with_reference
2106 // calls above) or we overflow.
2107 // Note: CMTask::do_marking_step() can set the CMTask::has_aborted() flag
2108 // while there may still be some work to do. (See the comment at the
2109 // beginning of CMTask::do_marking_step() for those conditions - one of which
2110 // is reaching the specified time target.) It is only when
2111 // CMTask::do_marking_step() returns without setting the has_aborted() flag
2112 // that the marking has completed.
2113 do {
2114 double mark_step_duration_ms = G1ConcMarkStepDurationMillis;
2115 _task->do_marking_step(mark_step_duration_ms,
2116 false /* do_stealing */,
2117 false /* do_termination */);
2118 } while (_task->has_aborted() && !_cm->has_overflown());
2119 _ref_counter = _ref_counter_limit;
2120 }
2121 } else {
2122 if (_cm->verbose_high()) {
2123 gclog_or_tty->print_cr("\t[%d] CM Overflow", _task->task_id());
2124 }
2125 }
2126 }
2127 };
2128
2129 class G1CMParDrainMarkingStackClosure: public VoidClosure {
2130 ConcurrentMark* _cm;
2131 CMTask* _task;
2132 public:
2133 G1CMParDrainMarkingStackClosure(ConcurrentMark* cm, CMTask* task) :
2134 _cm(cm), _task(task) { }
2135
2136 void do_void() {
2137 do {
2138 if (_cm->verbose_high()) {
2139 gclog_or_tty->print_cr("\t[%d] Drain: Calling do marking_step",
2140 _task->task_id());
2141 }
2142
2143 // We call CMTask::do_marking_step() to completely drain the local and
2144 // global marking stacks. The routine is called in a loop, which we'll
2145 // exit if there's nothing more to do (i.e. we'completely drained the
2146 // entries that were pushed as a result of applying the
2147 // G1CMParKeepAliveAndDrainClosure to the entries on the discovered ref
2148 // lists above) or we overflow the global marking stack.
2149 // Note: CMTask::do_marking_step() can set the CMTask::has_aborted() flag
2150 // while there may still be some work to do. (See the comment at the
2151 // beginning of CMTask::do_marking_step() for those conditions - one of which
2152 // is reaching the specified time target.) It is only when
2153 // CMTask::do_marking_step() returns without setting the has_aborted() flag
2154 // that the marking has completed.
2155
2156 _task->do_marking_step(1000000000.0 /* something very large */,
2157 true /* do_stealing */,
2158 true /* do_termination */);
2159 } while (_task->has_aborted() && !_cm->has_overflown());
2160 }
2161 };
2162
2163 // Implementation of AbstractRefProcTaskExecutor for parallel
2164 // reference processing at the end of G1 concurrent marking
2165
2166 class G1CMRefProcTaskExecutor: public AbstractRefProcTaskExecutor {
2167 private:
2168 G1CollectedHeap* _g1h;
2169 ConcurrentMark* _cm;
2170 WorkGang* _workers;
2171 int _active_workers;
2172
2173 public:
2174 G1CMRefProcTaskExecutor(G1CollectedHeap* g1h,
2175 ConcurrentMark* cm,
2176 WorkGang* workers,
2177 int n_workers) :
2178 _g1h(g1h), _cm(cm),
2179 _workers(workers), _active_workers(n_workers) { }
2180
2181 // Executes the given task using concurrent marking worker threads.
2182 virtual void execute(ProcessTask& task);
2183 virtual void execute(EnqueueTask& task);
2184 };
2185
2186 class G1CMRefProcTaskProxy: public AbstractGangTask {
2187 typedef AbstractRefProcTaskExecutor::ProcessTask ProcessTask;
2188 ProcessTask& _proc_task;
2189 G1CollectedHeap* _g1h;
2190 ConcurrentMark* _cm;
2191
2192 public:
2193 G1CMRefProcTaskProxy(ProcessTask& proc_task,
2194 G1CollectedHeap* g1h,
2195 ConcurrentMark* cm) :
2196 AbstractGangTask("Process reference objects in parallel"),
2197 _proc_task(proc_task), _g1h(g1h), _cm(cm) { }
2198
2199 virtual void work(uint worker_id) {
2200 CMTask* marking_task = _cm->task(worker_id);
2201 G1CMIsAliveClosure g1_is_alive(_g1h);
2202 G1CMParKeepAliveAndDrainClosure g1_par_keep_alive(_cm, marking_task);
2203 G1CMParDrainMarkingStackClosure g1_par_drain(_cm, marking_task);
2204
2205 _proc_task.work(worker_id, g1_is_alive, g1_par_keep_alive, g1_par_drain);
2206 }
2207 };
2208
2209 void G1CMRefProcTaskExecutor::execute(ProcessTask& proc_task) {
2210 assert(_workers != NULL, "Need parallel worker threads.");
2211
2212 G1CMRefProcTaskProxy proc_task_proxy(proc_task, _g1h, _cm);
2213
2214 // We need to reset the phase for each task execution so that
2215 // the termination protocol of CMTask::do_marking_step works.
2216 _cm->set_phase(_active_workers, false /* concurrent */);
2217 _g1h->set_par_threads(_active_workers);
2218 _workers->run_task(&proc_task_proxy);
2219 _g1h->set_par_threads(0);
2220 }
2221
2222 class G1CMRefEnqueueTaskProxy: public AbstractGangTask {
2223 typedef AbstractRefProcTaskExecutor::EnqueueTask EnqueueTask;
2224 EnqueueTask& _enq_task;
2225
2226 public:
2227 G1CMRefEnqueueTaskProxy(EnqueueTask& enq_task) :
2228 AbstractGangTask("Enqueue reference objects in parallel"),
2229 _enq_task(enq_task) { }
2230
2231 virtual void work(uint worker_id) {
2232 _enq_task.work(worker_id);
2233 }
2234 };
2235
2236 void G1CMRefProcTaskExecutor::execute(EnqueueTask& enq_task) {
2237 assert(_workers != NULL, "Need parallel worker threads.");
2238
2239 G1CMRefEnqueueTaskProxy enq_task_proxy(enq_task);
2240
2241 _g1h->set_par_threads(_active_workers);
2242 _workers->run_task(&enq_task_proxy);
2243 _g1h->set_par_threads(0);
2244 }
2245
2246 void ConcurrentMark::weakRefsWork(bool clear_all_soft_refs) {
2247 ResourceMark rm;
2248 HandleMark hm;
2249
2250 G1CollectedHeap* g1h = G1CollectedHeap::heap();
2251
2252 // Is alive closure.
2253 G1CMIsAliveClosure g1_is_alive(g1h);
2254
2255 // Inner scope to exclude the cleaning of the string and symbol
2256 // tables from the displayed time.
2257 {
2258 if (G1Log::finer()) {
2259 gclog_or_tty->put(' ');
2260 }
2261 TraceTime t("GC ref-proc", G1Log::finer(), false, gclog_or_tty);
2262
2263 ReferenceProcessor* rp = g1h->ref_processor_cm();
2264
2265 // See the comment in G1CollectedHeap::ref_processing_init()
2266 // about how reference processing currently works in G1.
2267
2268 // Process weak references.
2269 rp->setup_policy(clear_all_soft_refs);
2270 assert(_markStack.isEmpty(), "mark stack should be empty");
2271
2272 G1CMKeepAliveClosure g1_keep_alive(g1h, this);
2273 G1CMDrainMarkingStackClosure
2274 g1_drain_mark_stack(this, &_markStack, &g1_keep_alive);
2275
2276 // We use the work gang from the G1CollectedHeap and we utilize all
2277 // the worker threads.
2278 uint active_workers = g1h->workers() ? g1h->workers()->active_workers() : 1U;
2279 active_workers = MAX2(MIN2(active_workers, _max_task_num), 1U);
2280
2281 G1CMRefProcTaskExecutor par_task_executor(g1h, this,
2282 g1h->workers(), active_workers);
2283
2284 if (rp->processing_is_mt()) {
2285 // Set the degree of MT here. If the discovery is done MT, there
2286 // may have been a different number of threads doing the discovery
2287 // and a different number of discovered lists may have Ref objects.
2288 // That is OK as long as the Reference lists are balanced (see
2289 // balance_all_queues() and balance_queues()).
2290 rp->set_active_mt_degree(active_workers);
2291
2292 rp->process_discovered_references(&g1_is_alive,
2293 &g1_keep_alive,
2294 &g1_drain_mark_stack,
2295 &par_task_executor);
2296
2297 // The work routines of the parallel keep_alive and drain_marking_stack
2298 // will set the has_overflown flag if we overflow the global marking
2299 // stack.
2300 } else {
2301 rp->process_discovered_references(&g1_is_alive,
2302 &g1_keep_alive,
2303 &g1_drain_mark_stack,
2304 NULL);
2305 }
2306
2307 assert(_markStack.overflow() || _markStack.isEmpty(),
2308 "mark stack should be empty (unless it overflowed)");
2309 if (_markStack.overflow()) {
2310 // Should have been done already when we tried to push an
2311 // entry on to the global mark stack. But let's do it again.
2312 set_has_overflown();
2313 }
2314
2315 if (rp->processing_is_mt()) {
2316 assert(rp->num_q() == active_workers, "why not");
2317 rp->enqueue_discovered_references(&par_task_executor);
2318 } else {
2319 rp->enqueue_discovered_references();
2320 }
2321
2322 rp->verify_no_references_recorded();
2323 assert(!rp->discovery_enabled(), "Post condition");
2324 }
2325
2326 // Now clean up stale oops in StringTable
2327 StringTable::unlink(&g1_is_alive);
2328 // Clean up unreferenced symbols in symbol table.
2329 SymbolTable::unlink();
2330 }
2331
2332 void ConcurrentMark::swapMarkBitMaps() {
2333 CMBitMapRO* temp = _prevMarkBitMap;
2334 _prevMarkBitMap = (CMBitMapRO*)_nextMarkBitMap;
2335 _nextMarkBitMap = (CMBitMap*) temp;
2336 }
2337
2338 class CMRemarkTask: public AbstractGangTask {
2339 private:
2340 ConcurrentMark *_cm;
2341
2342 public:
2343 void work(uint worker_id) {
2344 // Since all available tasks are actually started, we should
2345 // only proceed if we're supposed to be actived.
2346 if (worker_id < _cm->active_tasks()) {
2347 CMTask* task = _cm->task(worker_id);
2348 task->record_start_time();
2349 do {
2350 task->do_marking_step(1000000000.0 /* something very large */,
2351 true /* do_stealing */,
2352 true /* do_termination */);
2353 } while (task->has_aborted() && !_cm->has_overflown());
2354 // If we overflow, then we do not want to restart. We instead
2355 // want to abort remark and do concurrent marking again.
2356 task->record_end_time();
2357 }
2358 }
2359
2360 CMRemarkTask(ConcurrentMark* cm, int active_workers) :
2361 AbstractGangTask("Par Remark"), _cm(cm) {
2362 _cm->terminator()->reset_for_reuse(active_workers);
2363 }
2364 };
2365
2366 void ConcurrentMark::checkpointRootsFinalWork() {
2367 ResourceMark rm;
2368 HandleMark hm;
2369 G1CollectedHeap* g1h = G1CollectedHeap::heap();
2370
2371 g1h->ensure_parsability(false);
2372
2373 if (G1CollectedHeap::use_parallel_gc_threads()) {
2374 G1CollectedHeap::StrongRootsScope srs(g1h);
2375 // this is remark, so we'll use up all active threads
2376 uint active_workers = g1h->workers()->active_workers();
2377 if (active_workers == 0) {
2378 assert(active_workers > 0, "Should have been set earlier");
2379 active_workers = (uint) ParallelGCThreads;
2380 g1h->workers()->set_active_workers(active_workers);
2381 }
2382 set_phase(active_workers, false /* concurrent */);
2383 // Leave _parallel_marking_threads at it's
2384 // value originally calculated in the ConcurrentMark
2385 // constructor and pass values of the active workers
2386 // through the gang in the task.
2387
2388 CMRemarkTask remarkTask(this, active_workers);
2389 g1h->set_par_threads(active_workers);
2390 g1h->workers()->run_task(&remarkTask);
2391 g1h->set_par_threads(0);
2392 } else {
2393 G1CollectedHeap::StrongRootsScope srs(g1h);
2394 // this is remark, so we'll use up all available threads
2395 uint active_workers = 1;
2396 set_phase(active_workers, false /* concurrent */);
2397
2398 CMRemarkTask remarkTask(this, active_workers);
2399 // We will start all available threads, even if we decide that the
2400 // active_workers will be fewer. The extra ones will just bail out
2401 // immediately.
2402 remarkTask.work(0);
2403 }
2404 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set();
2405 guarantee(satb_mq_set.completed_buffers_num() == 0, "invariant");
2406
2407 print_stats();
2408
2409 #if VERIFY_OBJS_PROCESSED
2410 if (_scan_obj_cl.objs_processed != ThreadLocalObjQueue::objs_enqueued) {
2411 gclog_or_tty->print_cr("Processed = %d, enqueued = %d.",
2412 _scan_obj_cl.objs_processed,
2413 ThreadLocalObjQueue::objs_enqueued);
2414 guarantee(_scan_obj_cl.objs_processed ==
2415 ThreadLocalObjQueue::objs_enqueued,
2416 "Different number of objs processed and enqueued.");
2417 }
2418 #endif
2419 }
2420
2421 #ifndef PRODUCT
2422
2423 class PrintReachableOopClosure: public OopClosure {
2424 private:
2425 G1CollectedHeap* _g1h;
2426 outputStream* _out;
2427 VerifyOption _vo;
2428 bool _all;
2429
2430 public:
2431 PrintReachableOopClosure(outputStream* out,
2432 VerifyOption vo,
2433 bool all) :
2434 _g1h(G1CollectedHeap::heap()),
2435 _out(out), _vo(vo), _all(all) { }
2436
2437 void do_oop(narrowOop* p) { do_oop_work(p); }
2438 void do_oop( oop* p) { do_oop_work(p); }
2439
2440 template <class T> void do_oop_work(T* p) {
2441 oop obj = oopDesc::load_decode_heap_oop(p);
2442 const char* str = NULL;
2443 const char* str2 = "";
2444
2445 if (obj == NULL) {
2446 str = "";
2447 } else if (!_g1h->is_in_g1_reserved(obj)) {
2448 str = " O";
2449 } else {
2450 HeapRegion* hr = _g1h->heap_region_containing(obj);
2451 guarantee(hr != NULL, "invariant");
2452 bool over_tams = _g1h->allocated_since_marking(obj, hr, _vo);
2453 bool marked = _g1h->is_marked(obj, _vo);
2454
2455 if (over_tams) {
2456 str = " >";
2457 if (marked) {
2458 str2 = " AND MARKED";
2459 }
2460 } else if (marked) {
2461 str = " M";
2462 } else {
2463 str = " NOT";
2464 }
2465 }
2466
2467 _out->print_cr(" "PTR_FORMAT": "PTR_FORMAT"%s%s",
2468 p, (void*) obj, str, str2);
2469 }
2470 };
2471
2472 class PrintReachableObjectClosure : public ObjectClosure {
2473 private:
2474 G1CollectedHeap* _g1h;
2475 outputStream* _out;
2476 VerifyOption _vo;
2477 bool _all;
2478 HeapRegion* _hr;
2479
2480 public:
2481 PrintReachableObjectClosure(outputStream* out,
2482 VerifyOption vo,
2483 bool all,
2484 HeapRegion* hr) :
2485 _g1h(G1CollectedHeap::heap()),
2486 _out(out), _vo(vo), _all(all), _hr(hr) { }
2487
2488 void do_object(oop o) {
2489 bool over_tams = _g1h->allocated_since_marking(o, _hr, _vo);
2490 bool marked = _g1h->is_marked(o, _vo);
2491 bool print_it = _all || over_tams || marked;
2492
2493 if (print_it) {
2494 _out->print_cr(" "PTR_FORMAT"%s",
2495 o, (over_tams) ? " >" : (marked) ? " M" : "");
2496 PrintReachableOopClosure oopCl(_out, _vo, _all);
2497 o->oop_iterate(&oopCl);
2498 }
2499 }
2500 };
2501
2502 class PrintReachableRegionClosure : public HeapRegionClosure {
2503 private:
2504 G1CollectedHeap* _g1h;
2505 outputStream* _out;
2506 VerifyOption _vo;
2507 bool _all;
2508
2509 public:
2510 bool doHeapRegion(HeapRegion* hr) {
2511 HeapWord* b = hr->bottom();
2512 HeapWord* e = hr->end();
2513 HeapWord* t = hr->top();
2514 HeapWord* p = _g1h->top_at_mark_start(hr, _vo);
2515 _out->print_cr("** ["PTR_FORMAT", "PTR_FORMAT"] top: "PTR_FORMAT" "
2516 "TAMS: "PTR_FORMAT, b, e, t, p);
2517 _out->cr();
2518
2519 HeapWord* from = b;
2520 HeapWord* to = t;
2521
2522 if (to > from) {
2523 _out->print_cr("Objects in ["PTR_FORMAT", "PTR_FORMAT"]", from, to);
2524 _out->cr();
2525 PrintReachableObjectClosure ocl(_out, _vo, _all, hr);
2526 hr->object_iterate_mem_careful(MemRegion(from, to), &ocl);
2527 _out->cr();
2528 }
2529
2530 return false;
2531 }
2532
2533 PrintReachableRegionClosure(outputStream* out,
2534 VerifyOption vo,
2535 bool all) :
2536 _g1h(G1CollectedHeap::heap()), _out(out), _vo(vo), _all(all) { }
2537 };
2538
2539 void ConcurrentMark::print_reachable(const char* str,
2540 VerifyOption vo,
2541 bool all) {
2542 gclog_or_tty->cr();
2543 gclog_or_tty->print_cr("== Doing heap dump... ");
2544
2545 if (G1PrintReachableBaseFile == NULL) {
2546 gclog_or_tty->print_cr(" #### error: no base file defined");
2547 return;
2548 }
2549
2550 if (strlen(G1PrintReachableBaseFile) + 1 + strlen(str) >
2551 (JVM_MAXPATHLEN - 1)) {
2552 gclog_or_tty->print_cr(" #### error: file name too long");
2553 return;
2554 }
2555
2556 char file_name[JVM_MAXPATHLEN];
2557 sprintf(file_name, "%s.%s", G1PrintReachableBaseFile, str);
2558 gclog_or_tty->print_cr(" dumping to file %s", file_name);
2559
2560 fileStream fout(file_name);
2561 if (!fout.is_open()) {
2562 gclog_or_tty->print_cr(" #### error: could not open file");
2563 return;
2564 }
2565
2566 outputStream* out = &fout;
2567 out->print_cr("-- USING %s", _g1h->top_at_mark_start_str(vo));
2568 out->cr();
2569
2570 out->print_cr("--- ITERATING OVER REGIONS");
2571 out->cr();
2572 PrintReachableRegionClosure rcl(out, vo, all);
2573 _g1h->heap_region_iterate(&rcl);
2574 out->cr();
2575
2576 gclog_or_tty->print_cr(" done");
2577 gclog_or_tty->flush();
2578 }
2579
2580 #endif // PRODUCT
2581
2582 void ConcurrentMark::clearRangePrevBitmap(MemRegion mr) {
2583 // Note we are overriding the read-only view of the prev map here, via
2584 // the cast.
2585 ((CMBitMap*)_prevMarkBitMap)->clearRange(mr);
2586 }
2587
2588 void ConcurrentMark::clearRangeNextBitmap(MemRegion mr) {
2589 _nextMarkBitMap->clearRange(mr);
2590 }
2591
2592 void ConcurrentMark::clearRangeBothBitmaps(MemRegion mr) {
2593 clearRangePrevBitmap(mr);
2594 clearRangeNextBitmap(mr);
2595 }
2596
2597 HeapRegion*
2598 ConcurrentMark::claim_region(int task_num) {
2599 // "checkpoint" the finger
2600 HeapWord* finger = _finger;
2601
2602 // _heap_end will not change underneath our feet; it only changes at
2603 // yield points.
2604 while (finger < _heap_end) {
2605 assert(_g1h->is_in_g1_reserved(finger), "invariant");
2606
2607 // Note on how this code handles humongous regions. In the
2608 // normal case the finger will reach the start of a "starts
2609 // humongous" (SH) region. Its end will either be the end of the
2610 // last "continues humongous" (CH) region in the sequence, or the
2611 // standard end of the SH region (if the SH is the only region in
2612 // the sequence). That way claim_region() will skip over the CH
2613 // regions. However, there is a subtle race between a CM thread
2614 // executing this method and a mutator thread doing a humongous
2615 // object allocation. The two are not mutually exclusive as the CM
2616 // thread does not need to hold the Heap_lock when it gets
2617 // here. So there is a chance that claim_region() will come across
2618 // a free region that's in the progress of becoming a SH or a CH
2619 // region. In the former case, it will either
2620 // a) Miss the update to the region's end, in which case it will
2621 // visit every subsequent CH region, will find their bitmaps
2622 // empty, and do nothing, or
2623 // b) Will observe the update of the region's end (in which case
2624 // it will skip the subsequent CH regions).
2625 // If it comes across a region that suddenly becomes CH, the
2626 // scenario will be similar to b). So, the race between
2627 // claim_region() and a humongous object allocation might force us
2628 // to do a bit of unnecessary work (due to some unnecessary bitmap
2629 // iterations) but it should not introduce and correctness issues.
2630 HeapRegion* curr_region = _g1h->heap_region_containing_raw(finger);
2631 HeapWord* bottom = curr_region->bottom();
2632 HeapWord* end = curr_region->end();
2633 HeapWord* limit = curr_region->next_top_at_mark_start();
2634
2635 if (verbose_low()) {
2636 gclog_or_tty->print_cr("[%d] curr_region = "PTR_FORMAT" "
2637 "["PTR_FORMAT", "PTR_FORMAT"), "
2638 "limit = "PTR_FORMAT,
2639 task_num, curr_region, bottom, end, limit);
2640 }
2641
2642 // Is the gap between reading the finger and doing the CAS too long?
2643 HeapWord* res = (HeapWord*) Atomic::cmpxchg_ptr(end, &_finger, finger);
2644 if (res == finger) {
2645 // we succeeded
2646
2647 // notice that _finger == end cannot be guaranteed here since,
2648 // someone else might have moved the finger even further
2649 assert(_finger >= end, "the finger should have moved forward");
2650
2651 if (verbose_low()) {
2652 gclog_or_tty->print_cr("[%d] we were successful with region = "
2653 PTR_FORMAT, task_num, curr_region);
2654 }
2655
2656 if (limit > bottom) {
2657 if (verbose_low()) {
2658 gclog_or_tty->print_cr("[%d] region "PTR_FORMAT" is not empty, "
2659 "returning it ", task_num, curr_region);
2660 }
2661 return curr_region;
2662 } else {
2663 assert(limit == bottom,
2664 "the region limit should be at bottom");
2665 if (verbose_low()) {
2666 gclog_or_tty->print_cr("[%d] region "PTR_FORMAT" is empty, "
2667 "returning NULL", task_num, curr_region);
2668 }
2669 // we return NULL and the caller should try calling
2670 // claim_region() again.
2671 return NULL;
2672 }
2673 } else {
2674 assert(_finger > finger, "the finger should have moved forward");
2675 if (verbose_low()) {
2676 gclog_or_tty->print_cr("[%d] somebody else moved the finger, "
2677 "global finger = "PTR_FORMAT", "
2678 "our finger = "PTR_FORMAT,
2679 task_num, _finger, finger);
2680 }
2681
2682 // read it again
2683 finger = _finger;
2684 }
2685 }
2686
2687 return NULL;
2688 }
2689
2690 #ifndef PRODUCT
2691 enum VerifyNoCSetOopsPhase {
2692 VerifyNoCSetOopsStack,
2693 VerifyNoCSetOopsQueues,
2694 VerifyNoCSetOopsSATBCompleted,
2695 VerifyNoCSetOopsSATBThread
2696 };
2697
2698 class VerifyNoCSetOopsClosure : public OopClosure, public ObjectClosure {
2699 private:
2700 G1CollectedHeap* _g1h;
2701 VerifyNoCSetOopsPhase _phase;
2702 int _info;
2703
2704 const char* phase_str() {
2705 switch (_phase) {
2706 case VerifyNoCSetOopsStack: return "Stack";
2707 case VerifyNoCSetOopsQueues: return "Queue";
2708 case VerifyNoCSetOopsSATBCompleted: return "Completed SATB Buffers";
2709 case VerifyNoCSetOopsSATBThread: return "Thread SATB Buffers";
2710 default: ShouldNotReachHere();
2711 }
2712 return NULL;
2713 }
2714
2715 void do_object_work(oop obj) {
2716 guarantee(!_g1h->obj_in_cs(obj),
2717 err_msg("obj: "PTR_FORMAT" in CSet, phase: %s, info: %d",
2718 (void*) obj, phase_str(), _info));
2719 }
2720
2721 public:
2722 VerifyNoCSetOopsClosure() : _g1h(G1CollectedHeap::heap()) { }
2723
2724 void set_phase(VerifyNoCSetOopsPhase phase, int info = -1) {
2725 _phase = phase;
2726 _info = info;
2727 }
2728
2729 virtual void do_oop(oop* p) {
2730 oop obj = oopDesc::load_decode_heap_oop(p);
2731 do_object_work(obj);
2732 }
2733
2734 virtual void do_oop(narrowOop* p) {
2735 // We should not come across narrow oops while scanning marking
2736 // stacks and SATB buffers.
2737 ShouldNotReachHere();
2738 }
2739
2740 virtual void do_object(oop obj) {
2741 do_object_work(obj);
2742 }
2743 };
2744
2745 void ConcurrentMark::verify_no_cset_oops(bool verify_stacks,
2746 bool verify_enqueued_buffers,
2747 bool verify_thread_buffers,
2748 bool verify_fingers) {
2749 assert(SafepointSynchronize::is_at_safepoint(), "should be at a safepoint");
2750 if (!G1CollectedHeap::heap()->mark_in_progress()) {
2751 return;
2752 }
2753
2754 VerifyNoCSetOopsClosure cl;
2755
2756 if (verify_stacks) {
2757 // Verify entries on the global mark stack
2758 cl.set_phase(VerifyNoCSetOopsStack);
2759 _markStack.oops_do(&cl);
2760
2761 // Verify entries on the task queues
2762 for (int i = 0; i < (int) _max_task_num; i += 1) {
2763 cl.set_phase(VerifyNoCSetOopsQueues, i);
2764 OopTaskQueue* queue = _task_queues->queue(i);
2765 queue->oops_do(&cl);
2766 }
2767 }
2768
2769 SATBMarkQueueSet& satb_qs = JavaThread::satb_mark_queue_set();
2770
2771 // Verify entries on the enqueued SATB buffers
2772 if (verify_enqueued_buffers) {
2773 cl.set_phase(VerifyNoCSetOopsSATBCompleted);
2774 satb_qs.iterate_completed_buffers_read_only(&cl);
2775 }
2776
2777 // Verify entries on the per-thread SATB buffers
2778 if (verify_thread_buffers) {
2779 cl.set_phase(VerifyNoCSetOopsSATBThread);
2780 satb_qs.iterate_thread_buffers_read_only(&cl);
2781 }
2782
2783 if (verify_fingers) {
2784 // Verify the global finger
2785 HeapWord* global_finger = finger();
2786 if (global_finger != NULL && global_finger < _heap_end) {
2787 // The global finger always points to a heap region boundary. We
2788 // use heap_region_containing_raw() to get the containing region
2789 // given that the global finger could be pointing to a free region
2790 // which subsequently becomes continues humongous. If that
2791 // happens, heap_region_containing() will return the bottom of the
2792 // corresponding starts humongous region and the check below will
2793 // not hold any more.
2794 HeapRegion* global_hr = _g1h->heap_region_containing_raw(global_finger);
2795 guarantee(global_finger == global_hr->bottom(),
2796 err_msg("global finger: "PTR_FORMAT" region: "HR_FORMAT,
2797 global_finger, HR_FORMAT_PARAMS(global_hr)));
2798 }
2799
2800 // Verify the task fingers
2801 assert(parallel_marking_threads() <= _max_task_num, "sanity");
2802 for (int i = 0; i < (int) parallel_marking_threads(); i += 1) {
2803 CMTask* task = _tasks[i];
2804 HeapWord* task_finger = task->finger();
2805 if (task_finger != NULL && task_finger < _heap_end) {
2806 // See above note on the global finger verification.
2807 HeapRegion* task_hr = _g1h->heap_region_containing_raw(task_finger);
2808 guarantee(task_finger == task_hr->bottom() ||
2809 !task_hr->in_collection_set(),
2810 err_msg("task finger: "PTR_FORMAT" region: "HR_FORMAT,
2811 task_finger, HR_FORMAT_PARAMS(task_hr)));
2812 }
2813 }
2814 }
2815 }
2816 #endif // PRODUCT
2817
2818 void ConcurrentMark::clear_marking_state(bool clear_overflow) {
2819 _markStack.setEmpty();
2820 _markStack.clear_overflow();
2821 if (clear_overflow) {
2822 clear_has_overflown();
2823 } else {
2824 assert(has_overflown(), "pre-condition");
2825 }
2826 _finger = _heap_start;
2827
2828 for (int i = 0; i < (int)_max_task_num; ++i) {
2829 OopTaskQueue* queue = _task_queues->queue(i);
2830 queue->set_empty();
2831 }
2832 }
2833
2834 // Aggregate the counting data that was constructed concurrently
2835 // with marking.
2836 class AggregateCountDataHRClosure: public HeapRegionClosure {
2837 ConcurrentMark* _cm;
2838 BitMap* _cm_card_bm;
2839 size_t _max_task_num;
2840
2841 public:
2842 AggregateCountDataHRClosure(ConcurrentMark *cm,
2843 BitMap* cm_card_bm,
2844 size_t max_task_num) :
2845 _cm(cm), _cm_card_bm(cm_card_bm),
2846 _max_task_num(max_task_num) { }
2847
2848 bool is_card_aligned(HeapWord* p) {
2849 return ((uintptr_t(p) & (CardTableModRefBS::card_size - 1)) == 0);
2850 }
2851
2852 bool doHeapRegion(HeapRegion* hr) {
2853 if (hr->continuesHumongous()) {
2854 // We will ignore these here and process them when their
2855 // associated "starts humongous" region is processed.
2856 // Note that we cannot rely on their associated
2857 // "starts humongous" region to have their bit set to 1
2858 // since, due to the region chunking in the parallel region
2859 // iteration, a "continues humongous" region might be visited
2860 // before its associated "starts humongous".
2861 return false;
2862 }
2863
2864 HeapWord* start = hr->bottom();
2865 HeapWord* limit = hr->next_top_at_mark_start();
2866 HeapWord* end = hr->end();
2867
2868 assert(start <= limit && limit <= hr->top() && hr->top() <= hr->end(),
2869 err_msg("Preconditions not met - "
2870 "start: "PTR_FORMAT", limit: "PTR_FORMAT", "
2871 "top: "PTR_FORMAT", end: "PTR_FORMAT,
2872 start, limit, hr->top(), hr->end()));
2873
2874 assert(hr->next_marked_bytes() == 0, "Precondition");
2875
2876 if (start == limit) {
2877 // NTAMS of this region has not been set so nothing to do.
2878 return false;
2879 }
2880
2881 assert(is_card_aligned(start), "sanity");
2882 assert(is_card_aligned(end), "sanity");
2883
2884 BitMap::idx_t start_idx = _cm->card_bitmap_index_for(start);
2885 BitMap::idx_t limit_idx = _cm->card_bitmap_index_for(limit);
2886 BitMap::idx_t end_idx = _cm->card_bitmap_index_for(end);
2887
2888 // If ntams is not card aligned then we bump the index for
2889 // limit so that we get the card spanning ntams.
2890 if (!is_card_aligned(limit)) {
2891 limit_idx += 1;
2892 }
2893
2894 assert(limit_idx <= end_idx, "or else use atomics");
2895
2896 // Aggregate the "stripe" in the count data associated with hr.
2897 uint hrs_index = hr->hrs_index();
2898 size_t marked_bytes = 0;
2899
2900 for (int i = 0; (size_t)i < _max_task_num; i += 1) {
2901 size_t* marked_bytes_array = _cm->count_marked_bytes_array_for(i);
2902 BitMap* task_card_bm = _cm->count_card_bitmap_for(i);
2903
2904 // Fetch the marked_bytes in this region for task i and
2905 // add it to the running total for this region.
2906 marked_bytes += marked_bytes_array[hrs_index];
2907
2908 // Now union the bitmaps[0,max_task_num)[start_idx..limit_idx)
2909 // into the global card bitmap.
2910 BitMap::idx_t scan_idx = task_card_bm->get_next_one_offset(start_idx, limit_idx);
2911
2912 while (scan_idx < limit_idx) {
2913 assert(task_card_bm->at(scan_idx) == true, "should be");
2914 _cm_card_bm->set_bit(scan_idx);
2915 assert(_cm_card_bm->at(scan_idx) == true, "should be");
2916
2917 // BitMap::get_next_one_offset() can handle the case when
2918 // its left_offset parameter is greater than its right_offset
2919 // parameter. If does, however, have an early exit if
2920 // left_offset == right_offset. So let's limit the value
2921 // passed in for left offset here.
2922 BitMap::idx_t next_idx = MIN2(scan_idx + 1, limit_idx);
2923 scan_idx = task_card_bm->get_next_one_offset(next_idx, limit_idx);
2924 }
2925 }
2926
2927 // Update the marked bytes for this region.
2928 hr->add_to_marked_bytes(marked_bytes);
2929
2930 // Next heap region
2931 return false;
2932 }
2933 };
2934
2935 class G1AggregateCountDataTask: public AbstractGangTask {
2936 protected:
2937 G1CollectedHeap* _g1h;
2938 ConcurrentMark* _cm;
2939 BitMap* _cm_card_bm;
2940 size_t _max_task_num;
2941 int _active_workers;
2942
2943 public:
2944 G1AggregateCountDataTask(G1CollectedHeap* g1h,
2945 ConcurrentMark* cm,
2946 BitMap* cm_card_bm,
2947 size_t max_task_num,
2948 int n_workers) :
2949 AbstractGangTask("Count Aggregation"),
2950 _g1h(g1h), _cm(cm), _cm_card_bm(cm_card_bm),
2951 _max_task_num(max_task_num),
2952 _active_workers(n_workers) { }
2953
2954 void work(uint worker_id) {
2955 AggregateCountDataHRClosure cl(_cm, _cm_card_bm, _max_task_num);
2956
2957 if (G1CollectedHeap::use_parallel_gc_threads()) {
2958 _g1h->heap_region_par_iterate_chunked(&cl, worker_id,
2959 _active_workers,
2960 HeapRegion::AggregateCountClaimValue);
2961 } else {
2962 _g1h->heap_region_iterate(&cl);
2963 }
2964 }
2965 };
2966
2967
2968 void ConcurrentMark::aggregate_count_data() {
2969 int n_workers = (G1CollectedHeap::use_parallel_gc_threads() ?
2970 _g1h->workers()->active_workers() :
2971 1);
2972
2973 G1AggregateCountDataTask g1_par_agg_task(_g1h, this, &_card_bm,
2974 _max_task_num, n_workers);
2975
2976 if (G1CollectedHeap::use_parallel_gc_threads()) {
2977 assert(_g1h->check_heap_region_claim_values(HeapRegion::InitialClaimValue),
2978 "sanity check");
2979 _g1h->set_par_threads(n_workers);
2980 _g1h->workers()->run_task(&g1_par_agg_task);
2981 _g1h->set_par_threads(0);
2982
2983 assert(_g1h->check_heap_region_claim_values(HeapRegion::AggregateCountClaimValue),
2984 "sanity check");
2985 _g1h->reset_heap_region_claim_values();
2986 } else {
2987 g1_par_agg_task.work(0);
2988 }
2989 }
2990
2991 // Clear the per-worker arrays used to store the per-region counting data
2992 void ConcurrentMark::clear_all_count_data() {
2993 // Clear the global card bitmap - it will be filled during
2994 // liveness count aggregation (during remark) and the
2995 // final counting task.
2996 _card_bm.clear();
2997
2998 // Clear the global region bitmap - it will be filled as part
2999 // of the final counting task.
3000 _region_bm.clear();
3001
3002 uint max_regions = _g1h->max_regions();
3003 assert(_max_task_num != 0, "unitialized");
3004
3005 for (int i = 0; (size_t) i < _max_task_num; i += 1) {
3006 BitMap* task_card_bm = count_card_bitmap_for(i);
3007 size_t* marked_bytes_array = count_marked_bytes_array_for(i);
3008
3009 assert(task_card_bm->size() == _card_bm.size(), "size mismatch");
3010 assert(marked_bytes_array != NULL, "uninitialized");
3011
3012 memset(marked_bytes_array, 0, (size_t) max_regions * sizeof(size_t));
3013 task_card_bm->clear();
3014 }
3015 }
3016
3017 void ConcurrentMark::print_stats() {
3018 if (verbose_stats()) {
3019 gclog_or_tty->print_cr("---------------------------------------------------------------------");
3020 for (size_t i = 0; i < _active_tasks; ++i) {
3021 _tasks[i]->print_stats();
3022 gclog_or_tty->print_cr("---------------------------------------------------------------------");
3023 }
3024 }
3025 }
3026
3027 // abandon current marking iteration due to a Full GC
3028 void ConcurrentMark::abort() {
3029 // Clear all marks to force marking thread to do nothing
3030 _nextMarkBitMap->clearAll();
3031 // Clear the liveness counting data
3032 clear_all_count_data();
3033 // Empty mark stack
3034 clear_marking_state();
3035 for (int i = 0; i < (int)_max_task_num; ++i) {
3036 _tasks[i]->clear_region_fields();
3037 }
3038 _has_aborted = true;
3039
3040 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set();
3041 satb_mq_set.abandon_partial_marking();
3042 // This can be called either during or outside marking, we'll read
3043 // the expected_active value from the SATB queue set.
3044 satb_mq_set.set_active_all_threads(
3045 false, /* new active value */
3046 satb_mq_set.is_active() /* expected_active */);
3047 }
3048
3049 static void print_ms_time_info(const char* prefix, const char* name,
3050 NumberSeq& ns) {
3051 gclog_or_tty->print_cr("%s%5d %12s: total time = %8.2f s (avg = %8.2f ms).",
3052 prefix, ns.num(), name, ns.sum()/1000.0, ns.avg());
3053 if (ns.num() > 0) {
3054 gclog_or_tty->print_cr("%s [std. dev = %8.2f ms, max = %8.2f ms]",
3055 prefix, ns.sd(), ns.maximum());
3056 }
3057 }
3058
3059 void ConcurrentMark::print_summary_info() {
3060 gclog_or_tty->print_cr(" Concurrent marking:");
3061 print_ms_time_info(" ", "init marks", _init_times);
3062 print_ms_time_info(" ", "remarks", _remark_times);
3063 {
3064 print_ms_time_info(" ", "final marks", _remark_mark_times);
3065 print_ms_time_info(" ", "weak refs", _remark_weak_ref_times);
3066
3067 }
3068 print_ms_time_info(" ", "cleanups", _cleanup_times);
3069 gclog_or_tty->print_cr(" Final counting total time = %8.2f s (avg = %8.2f ms).",
3070 _total_counting_time,
3071 (_cleanup_times.num() > 0 ? _total_counting_time * 1000.0 /
3072 (double)_cleanup_times.num()
3073 : 0.0));
3074 if (G1ScrubRemSets) {
3075 gclog_or_tty->print_cr(" RS scrub total time = %8.2f s (avg = %8.2f ms).",
3076 _total_rs_scrub_time,
3077 (_cleanup_times.num() > 0 ? _total_rs_scrub_time * 1000.0 /
3078 (double)_cleanup_times.num()
3079 : 0.0));
3080 }
3081 gclog_or_tty->print_cr(" Total stop_world time = %8.2f s.",
3082 (_init_times.sum() + _remark_times.sum() +
3083 _cleanup_times.sum())/1000.0);
3084 gclog_or_tty->print_cr(" Total concurrent time = %8.2f s "
3085 "(%8.2f s marking).",
3086 cmThread()->vtime_accum(),
3087 cmThread()->vtime_mark_accum());
3088 }
3089
3090 void ConcurrentMark::print_worker_threads_on(outputStream* st) const {
3091 _parallel_workers->print_worker_threads_on(st);
3092 }
3093
3094 // We take a break if someone is trying to stop the world.
3095 bool ConcurrentMark::do_yield_check(uint worker_id) {
3096 if (should_yield()) {
3097 if (worker_id == 0) {
3098 _g1h->g1_policy()->record_concurrent_pause();
3099 }
3100 cmThread()->yield();
3101 return true;
3102 } else {
3103 return false;
3104 }
3105 }
3106
3107 bool ConcurrentMark::should_yield() {
3108 return cmThread()->should_yield();
3109 }
3110
3111 bool ConcurrentMark::containing_card_is_marked(void* p) {
3112 size_t offset = pointer_delta(p, _g1h->reserved_region().start(), 1);
3113 return _card_bm.at(offset >> CardTableModRefBS::card_shift);
3114 }
3115
3116 bool ConcurrentMark::containing_cards_are_marked(void* start,
3117 void* last) {
3118 return containing_card_is_marked(start) &&
3119 containing_card_is_marked(last);
3120 }
3121
3122 #ifndef PRODUCT
3123 // for debugging purposes
3124 void ConcurrentMark::print_finger() {
3125 gclog_or_tty->print_cr("heap ["PTR_FORMAT", "PTR_FORMAT"), global finger = "PTR_FORMAT,
3126 _heap_start, _heap_end, _finger);
3127 for (int i = 0; i < (int) _max_task_num; ++i) {
3128 gclog_or_tty->print(" %d: "PTR_FORMAT, i, _tasks[i]->finger());
3129 }
3130 gclog_or_tty->print_cr("");
3131 }
3132 #endif
3133
3134 void CMTask::scan_object(oop obj) {
3135 assert(_nextMarkBitMap->isMarked((HeapWord*) obj), "invariant");
3136
3137 if (_cm->verbose_high()) {
3138 gclog_or_tty->print_cr("[%d] we're scanning object "PTR_FORMAT,
3139 _task_id, (void*) obj);
3140 }
3141
3142 size_t obj_size = obj->size();
3143 _words_scanned += obj_size;
3144
3145 obj->oop_iterate(_cm_oop_closure);
3146 statsOnly( ++_objs_scanned );
3147 check_limits();
3148 }
3149
3150 // Closure for iteration over bitmaps
3151 class CMBitMapClosure : public BitMapClosure {
3152 private:
3153 // the bitmap that is being iterated over
3154 CMBitMap* _nextMarkBitMap;
3155 ConcurrentMark* _cm;
3156 CMTask* _task;
3157
3158 public:
3159 CMBitMapClosure(CMTask *task, ConcurrentMark* cm, CMBitMap* nextMarkBitMap) :
3160 _task(task), _cm(cm), _nextMarkBitMap(nextMarkBitMap) { }
3161
3162 bool do_bit(size_t offset) {
3163 HeapWord* addr = _nextMarkBitMap->offsetToHeapWord(offset);
3164 assert(_nextMarkBitMap->isMarked(addr), "invariant");
3165 assert( addr < _cm->finger(), "invariant");
3166
3167 statsOnly( _task->increase_objs_found_on_bitmap() );
3168 assert(addr >= _task->finger(), "invariant");
3169
3170 // We move that task's local finger along.
3171 _task->move_finger_to(addr);
3172
3173 _task->scan_object(oop(addr));
3174 // we only partially drain the local queue and global stack
3175 _task->drain_local_queue(true);
3176 _task->drain_global_stack(true);
3177
3178 // if the has_aborted flag has been raised, we need to bail out of
3179 // the iteration
3180 return !_task->has_aborted();
3181 }
3182 };
3183
3184 // Closure for iterating over objects, currently only used for
3185 // processing SATB buffers.
3186 class CMObjectClosure : public ObjectClosure {
3187 private:
3188 CMTask* _task;
3189
3190 public:
3191 void do_object(oop obj) {
3192 _task->deal_with_reference(obj);
3193 }
3194
3195 CMObjectClosure(CMTask* task) : _task(task) { }
3196 };
3197
3198 G1CMOopClosure::G1CMOopClosure(G1CollectedHeap* g1h,
3199 ConcurrentMark* cm,
3200 CMTask* task)
3201 : _g1h(g1h), _cm(cm), _task(task) {
3202 assert(_ref_processor == NULL, "should be initialized to NULL");
3203
3204 if (G1UseConcMarkReferenceProcessing) {
3205 _ref_processor = g1h->ref_processor_cm();
3206 assert(_ref_processor != NULL, "should not be NULL");
3207 }
3208 }
3209
3210 void CMTask::setup_for_region(HeapRegion* hr) {
3211 // Separated the asserts so that we know which one fires.
3212 assert(hr != NULL,
3213 "claim_region() should have filtered out continues humongous regions");
3214 assert(!hr->continuesHumongous(),
3215 "claim_region() should have filtered out continues humongous regions");
3216
3217 if (_cm->verbose_low()) {
3218 gclog_or_tty->print_cr("[%d] setting up for region "PTR_FORMAT,
3219 _task_id, hr);
3220 }
3221
3222 _curr_region = hr;
3223 _finger = hr->bottom();
3224 update_region_limit();
3225 }
3226
3227 void CMTask::update_region_limit() {
3228 HeapRegion* hr = _curr_region;
3229 HeapWord* bottom = hr->bottom();
3230 HeapWord* limit = hr->next_top_at_mark_start();
3231
3232 if (limit == bottom) {
3233 if (_cm->verbose_low()) {
3234 gclog_or_tty->print_cr("[%d] found an empty region "
3235 "["PTR_FORMAT", "PTR_FORMAT")",
3236 _task_id, bottom, limit);
3237 }
3238 // The region was collected underneath our feet.
3239 // We set the finger to bottom to ensure that the bitmap
3240 // iteration that will follow this will not do anything.
3241 // (this is not a condition that holds when we set the region up,
3242 // as the region is not supposed to be empty in the first place)
3243 _finger = bottom;
3244 } else if (limit >= _region_limit) {
3245 assert(limit >= _finger, "peace of mind");
3246 } else {
3247 assert(limit < _region_limit, "only way to get here");
3248 // This can happen under some pretty unusual circumstances. An
3249 // evacuation pause empties the region underneath our feet (NTAMS
3250 // at bottom). We then do some allocation in the region (NTAMS
3251 // stays at bottom), followed by the region being used as a GC
3252 // alloc region (NTAMS will move to top() and the objects
3253 // originally below it will be grayed). All objects now marked in
3254 // the region are explicitly grayed, if below the global finger,
3255 // and we do not need in fact to scan anything else. So, we simply
3256 // set _finger to be limit to ensure that the bitmap iteration
3257 // doesn't do anything.
3258 _finger = limit;
3259 }
3260
3261 _region_limit = limit;
3262 }
3263
3264 void CMTask::giveup_current_region() {
3265 assert(_curr_region != NULL, "invariant");
3266 if (_cm->verbose_low()) {
3267 gclog_or_tty->print_cr("[%d] giving up region "PTR_FORMAT,
3268 _task_id, _curr_region);
3269 }
3270 clear_region_fields();
3271 }
3272
3273 void CMTask::clear_region_fields() {
3274 // Values for these three fields that indicate that we're not
3275 // holding on to a region.
3276 _curr_region = NULL;
3277 _finger = NULL;
3278 _region_limit = NULL;
3279 }
3280
3281 void CMTask::set_cm_oop_closure(G1CMOopClosure* cm_oop_closure) {
3282 if (cm_oop_closure == NULL) {
3283 assert(_cm_oop_closure != NULL, "invariant");
3284 } else {
3285 assert(_cm_oop_closure == NULL, "invariant");
3286 }
3287 _cm_oop_closure = cm_oop_closure;
3288 }
3289
3290 void CMTask::reset(CMBitMap* nextMarkBitMap) {
3291 guarantee(nextMarkBitMap != NULL, "invariant");
3292
3293 if (_cm->verbose_low()) {
3294 gclog_or_tty->print_cr("[%d] resetting", _task_id);
3295 }
3296
3297 _nextMarkBitMap = nextMarkBitMap;
3298 clear_region_fields();
3299
3300 _calls = 0;
3301 _elapsed_time_ms = 0.0;
3302 _termination_time_ms = 0.0;
3303 _termination_start_time_ms = 0.0;
3304
3305 #if _MARKING_STATS_
3306 _local_pushes = 0;
3307 _local_pops = 0;
3308 _local_max_size = 0;
3309 _objs_scanned = 0;
3310 _global_pushes = 0;
3311 _global_pops = 0;
3312 _global_max_size = 0;
3313 _global_transfers_to = 0;
3314 _global_transfers_from = 0;
3315 _regions_claimed = 0;
3316 _objs_found_on_bitmap = 0;
3317 _satb_buffers_processed = 0;
3318 _steal_attempts = 0;
3319 _steals = 0;
3320 _aborted = 0;
3321 _aborted_overflow = 0;
3322 _aborted_cm_aborted = 0;
3323 _aborted_yield = 0;
3324 _aborted_timed_out = 0;
3325 _aborted_satb = 0;
3326 _aborted_termination = 0;
3327 #endif // _MARKING_STATS_
3328 }
3329
3330 bool CMTask::should_exit_termination() {
3331 regular_clock_call();
3332 // This is called when we are in the termination protocol. We should
3333 // quit if, for some reason, this task wants to abort or the global
3334 // stack is not empty (this means that we can get work from it).
3335 return !_cm->mark_stack_empty() || has_aborted();
3336 }
3337
3338 void CMTask::reached_limit() {
3339 assert(_words_scanned >= _words_scanned_limit ||
3340 _refs_reached >= _refs_reached_limit ,
3341 "shouldn't have been called otherwise");
3342 regular_clock_call();
3343 }
3344
3345 void CMTask::regular_clock_call() {
3346 if (has_aborted()) return;
3347
3348 // First, we need to recalculate the words scanned and refs reached
3349 // limits for the next clock call.
3350 recalculate_limits();
3351
3352 // During the regular clock call we do the following
3353
3354 // (1) If an overflow has been flagged, then we abort.
3355 if (_cm->has_overflown()) {
3356 set_has_aborted();
3357 return;
3358 }
3359
3360 // If we are not concurrent (i.e. we're doing remark) we don't need
3361 // to check anything else. The other steps are only needed during
3362 // the concurrent marking phase.
3363 if (!concurrent()) return;
3364
3365 // (2) If marking has been aborted for Full GC, then we also abort.
3366 if (_cm->has_aborted()) {
3367 set_has_aborted();
3368 statsOnly( ++_aborted_cm_aborted );
3369 return;
3370 }
3371
3372 double curr_time_ms = os::elapsedVTime() * 1000.0;
3373
3374 // (3) If marking stats are enabled, then we update the step history.
3375 #if _MARKING_STATS_
3376 if (_words_scanned >= _words_scanned_limit) {
3377 ++_clock_due_to_scanning;
3378 }
3379 if (_refs_reached >= _refs_reached_limit) {
3380 ++_clock_due_to_marking;
3381 }
3382
3383 double last_interval_ms = curr_time_ms - _interval_start_time_ms;
3384 _interval_start_time_ms = curr_time_ms;
3385 _all_clock_intervals_ms.add(last_interval_ms);
3386
3387 if (_cm->verbose_medium()) {
3388 gclog_or_tty->print_cr("[%d] regular clock, interval = %1.2lfms, "
3389 "scanned = %d%s, refs reached = %d%s",
3390 _task_id, last_interval_ms,
3391 _words_scanned,
3392 (_words_scanned >= _words_scanned_limit) ? " (*)" : "",
3393 _refs_reached,
3394 (_refs_reached >= _refs_reached_limit) ? " (*)" : "");
3395 }
3396 #endif // _MARKING_STATS_
3397
3398 // (4) We check whether we should yield. If we have to, then we abort.
3399 if (_cm->should_yield()) {
3400 // We should yield. To do this we abort the task. The caller is
3401 // responsible for yielding.
3402 set_has_aborted();
3403 statsOnly( ++_aborted_yield );
3404 return;
3405 }
3406
3407 // (5) We check whether we've reached our time quota. If we have,
3408 // then we abort.
3409 double elapsed_time_ms = curr_time_ms - _start_time_ms;
3410 if (elapsed_time_ms > _time_target_ms) {
3411 set_has_aborted();
3412 _has_timed_out = true;
3413 statsOnly( ++_aborted_timed_out );
3414 return;
3415 }
3416
3417 // (6) Finally, we check whether there are enough completed STAB
3418 // buffers available for processing. If there are, we abort.
3419 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set();
3420 if (!_draining_satb_buffers && satb_mq_set.process_completed_buffers()) {
3421 if (_cm->verbose_low()) {
3422 gclog_or_tty->print_cr("[%d] aborting to deal with pending SATB buffers",
3423 _task_id);
3424 }
3425 // we do need to process SATB buffers, we'll abort and restart
3426 // the marking task to do so
3427 set_has_aborted();
3428 statsOnly( ++_aborted_satb );
3429 return;
3430 }
3431 }
3432
3433 void CMTask::recalculate_limits() {
3434 _real_words_scanned_limit = _words_scanned + words_scanned_period;
3435 _words_scanned_limit = _real_words_scanned_limit;
3436
3437 _real_refs_reached_limit = _refs_reached + refs_reached_period;
3438 _refs_reached_limit = _real_refs_reached_limit;
3439 }
3440
3441 void CMTask::decrease_limits() {
3442 // This is called when we believe that we're going to do an infrequent
3443 // operation which will increase the per byte scanned cost (i.e. move
3444 // entries to/from the global stack). It basically tries to decrease the
3445 // scanning limit so that the clock is called earlier.
3446
3447 if (_cm->verbose_medium()) {
3448 gclog_or_tty->print_cr("[%d] decreasing limits", _task_id);
3449 }
3450
3451 _words_scanned_limit = _real_words_scanned_limit -
3452 3 * words_scanned_period / 4;
3453 _refs_reached_limit = _real_refs_reached_limit -
3454 3 * refs_reached_period / 4;
3455 }
3456
3457 void CMTask::move_entries_to_global_stack() {
3458 // local array where we'll store the entries that will be popped
3459 // from the local queue
3460 oop buffer[global_stack_transfer_size];
3461
3462 int n = 0;
3463 oop obj;
3464 while (n < global_stack_transfer_size && _task_queue->pop_local(obj)) {
3465 buffer[n] = obj;
3466 ++n;
3467 }
3468
3469 if (n > 0) {
3470 // we popped at least one entry from the local queue
3471
3472 statsOnly( ++_global_transfers_to; _local_pops += n );
3473
3474 if (!_cm->mark_stack_push(buffer, n)) {
3475 if (_cm->verbose_low()) {
3476 gclog_or_tty->print_cr("[%d] aborting due to global stack overflow",
3477 _task_id);
3478 }
3479 set_has_aborted();
3480 } else {
3481 // the transfer was successful
3482
3483 if (_cm->verbose_medium()) {
3484 gclog_or_tty->print_cr("[%d] pushed %d entries to the global stack",
3485 _task_id, n);
3486 }
3487 statsOnly( int tmp_size = _cm->mark_stack_size();
3488 if (tmp_size > _global_max_size) {
3489 _global_max_size = tmp_size;
3490 }
3491 _global_pushes += n );
3492 }
3493 }
3494
3495 // this operation was quite expensive, so decrease the limits
3496 decrease_limits();
3497 }
3498
3499 void CMTask::get_entries_from_global_stack() {
3500 // local array where we'll store the entries that will be popped
3501 // from the global stack.
3502 oop buffer[global_stack_transfer_size];
3503 int n;
3504 _cm->mark_stack_pop(buffer, global_stack_transfer_size, &n);
3505 assert(n <= global_stack_transfer_size,
3506 "we should not pop more than the given limit");
3507 if (n > 0) {
3508 // yes, we did actually pop at least one entry
3509
3510 statsOnly( ++_global_transfers_from; _global_pops += n );
3511 if (_cm->verbose_medium()) {
3512 gclog_or_tty->print_cr("[%d] popped %d entries from the global stack",
3513 _task_id, n);
3514 }
3515 for (int i = 0; i < n; ++i) {
3516 bool success = _task_queue->push(buffer[i]);
3517 // We only call this when the local queue is empty or under a
3518 // given target limit. So, we do not expect this push to fail.
3519 assert(success, "invariant");
3520 }
3521
3522 statsOnly( int tmp_size = _task_queue->size();
3523 if (tmp_size > _local_max_size) {
3524 _local_max_size = tmp_size;
3525 }
3526 _local_pushes += n );
3527 }
3528
3529 // this operation was quite expensive, so decrease the limits
3530 decrease_limits();
3531 }
3532
3533 void CMTask::drain_local_queue(bool partially) {
3534 if (has_aborted()) return;
3535
3536 // Decide what the target size is, depending whether we're going to
3537 // drain it partially (so that other tasks can steal if they run out
3538 // of things to do) or totally (at the very end).
3539 size_t target_size;
3540 if (partially) {
3541 target_size = MIN2((size_t)_task_queue->max_elems()/3, GCDrainStackTargetSize);
3542 } else {
3543 target_size = 0;
3544 }
3545
3546 if (_task_queue->size() > target_size) {
3547 if (_cm->verbose_high()) {
3548 gclog_or_tty->print_cr("[%d] draining local queue, target size = %d",
3549 _task_id, target_size);
3550 }
3551
3552 oop obj;
3553 bool ret = _task_queue->pop_local(obj);
3554 while (ret) {
3555 statsOnly( ++_local_pops );
3556
3557 if (_cm->verbose_high()) {
3558 gclog_or_tty->print_cr("[%d] popped "PTR_FORMAT, _task_id,
3559 (void*) obj);
3560 }
3561
3562 assert(_g1h->is_in_g1_reserved((HeapWord*) obj), "invariant" );
3563 assert(!_g1h->is_on_master_free_list(
3564 _g1h->heap_region_containing((HeapWord*) obj)), "invariant");
3565
3566 scan_object(obj);
3567
3568 if (_task_queue->size() <= target_size || has_aborted()) {
3569 ret = false;
3570 } else {
3571 ret = _task_queue->pop_local(obj);
3572 }
3573 }
3574
3575 if (_cm->verbose_high()) {
3576 gclog_or_tty->print_cr("[%d] drained local queue, size = %d",
3577 _task_id, _task_queue->size());
3578 }
3579 }
3580 }
3581
3582 void CMTask::drain_global_stack(bool partially) {
3583 if (has_aborted()) return;
3584
3585 // We have a policy to drain the local queue before we attempt to
3586 // drain the global stack.
3587 assert(partially || _task_queue->size() == 0, "invariant");
3588
3589 // Decide what the target size is, depending whether we're going to
3590 // drain it partially (so that other tasks can steal if they run out
3591 // of things to do) or totally (at the very end). Notice that,
3592 // because we move entries from the global stack in chunks or
3593 // because another task might be doing the same, we might in fact
3594 // drop below the target. But, this is not a problem.
3595 size_t target_size;
3596 if (partially) {
3597 target_size = _cm->partial_mark_stack_size_target();
3598 } else {
3599 target_size = 0;
3600 }
3601
3602 if (_cm->mark_stack_size() > target_size) {
3603 if (_cm->verbose_low()) {
3604 gclog_or_tty->print_cr("[%d] draining global_stack, target size %d",
3605 _task_id, target_size);
3606 }
3607
3608 while (!has_aborted() && _cm->mark_stack_size() > target_size) {
3609 get_entries_from_global_stack();
3610 drain_local_queue(partially);
3611 }
3612
3613 if (_cm->verbose_low()) {
3614 gclog_or_tty->print_cr("[%d] drained global stack, size = %d",
3615 _task_id, _cm->mark_stack_size());
3616 }
3617 }
3618 }
3619
3620 // SATB Queue has several assumptions on whether to call the par or
3621 // non-par versions of the methods. this is why some of the code is
3622 // replicated. We should really get rid of the single-threaded version
3623 // of the code to simplify things.
3624 void CMTask::drain_satb_buffers() {
3625 if (has_aborted()) return;
3626
3627 // We set this so that the regular clock knows that we're in the
3628 // middle of draining buffers and doesn't set the abort flag when it
3629 // notices that SATB buffers are available for draining. It'd be
3630 // very counter productive if it did that. :-)
3631 _draining_satb_buffers = true;
3632
3633 CMObjectClosure oc(this);
3634 SATBMarkQueueSet& satb_mq_set = JavaThread::satb_mark_queue_set();
3635 if (G1CollectedHeap::use_parallel_gc_threads()) {
3636 satb_mq_set.set_par_closure(_task_id, &oc);
3637 } else {
3638 satb_mq_set.set_closure(&oc);
3639 }
3640
3641 // This keeps claiming and applying the closure to completed buffers
3642 // until we run out of buffers or we need to abort.
3643 if (G1CollectedHeap::use_parallel_gc_threads()) {
3644 while (!has_aborted() &&
3645 satb_mq_set.par_apply_closure_to_completed_buffer(_task_id)) {
3646 if (_cm->verbose_medium()) {
3647 gclog_or_tty->print_cr("[%d] processed an SATB buffer", _task_id);
3648 }
3649 statsOnly( ++_satb_buffers_processed );
3650 regular_clock_call();
3651 }
3652 } else {
3653 while (!has_aborted() &&
3654 satb_mq_set.apply_closure_to_completed_buffer()) {
3655 if (_cm->verbose_medium()) {
3656 gclog_or_tty->print_cr("[%d] processed an SATB buffer", _task_id);
3657 }
3658 statsOnly( ++_satb_buffers_processed );
3659 regular_clock_call();
3660 }
3661 }
3662
3663 if (!concurrent() && !has_aborted()) {
3664 // We should only do this during remark.
3665 if (G1CollectedHeap::use_parallel_gc_threads()) {
3666 satb_mq_set.par_iterate_closure_all_threads(_task_id);
3667 } else {
3668 satb_mq_set.iterate_closure_all_threads();
3669 }
3670 }
3671
3672 _draining_satb_buffers = false;
3673
3674 assert(has_aborted() ||
3675 concurrent() ||
3676 satb_mq_set.completed_buffers_num() == 0, "invariant");
3677
3678 if (G1CollectedHeap::use_parallel_gc_threads()) {
3679 satb_mq_set.set_par_closure(_task_id, NULL);
3680 } else {
3681 satb_mq_set.set_closure(NULL);
3682 }
3683
3684 // again, this was a potentially expensive operation, decrease the
3685 // limits to get the regular clock call early
3686 decrease_limits();
3687 }
3688
3689 void CMTask::print_stats() {
3690 gclog_or_tty->print_cr("Marking Stats, task = %d, calls = %d",
3691 _task_id, _calls);
3692 gclog_or_tty->print_cr(" Elapsed time = %1.2lfms, Termination time = %1.2lfms",
3693 _elapsed_time_ms, _termination_time_ms);
3694 gclog_or_tty->print_cr(" Step Times (cum): num = %d, avg = %1.2lfms, sd = %1.2lfms",
3695 _step_times_ms.num(), _step_times_ms.avg(),
3696 _step_times_ms.sd());
3697 gclog_or_tty->print_cr(" max = %1.2lfms, total = %1.2lfms",
3698 _step_times_ms.maximum(), _step_times_ms.sum());
3699
3700 #if _MARKING_STATS_
3701 gclog_or_tty->print_cr(" Clock Intervals (cum): num = %d, avg = %1.2lfms, sd = %1.2lfms",
3702 _all_clock_intervals_ms.num(), _all_clock_intervals_ms.avg(),
3703 _all_clock_intervals_ms.sd());
3704 gclog_or_tty->print_cr(" max = %1.2lfms, total = %1.2lfms",
3705 _all_clock_intervals_ms.maximum(),
3706 _all_clock_intervals_ms.sum());
3707 gclog_or_tty->print_cr(" Clock Causes (cum): scanning = %d, marking = %d",
3708 _clock_due_to_scanning, _clock_due_to_marking);
3709 gclog_or_tty->print_cr(" Objects: scanned = %d, found on the bitmap = %d",
3710 _objs_scanned, _objs_found_on_bitmap);
3711 gclog_or_tty->print_cr(" Local Queue: pushes = %d, pops = %d, max size = %d",
3712 _local_pushes, _local_pops, _local_max_size);
3713 gclog_or_tty->print_cr(" Global Stack: pushes = %d, pops = %d, max size = %d",
3714 _global_pushes, _global_pops, _global_max_size);
3715 gclog_or_tty->print_cr(" transfers to = %d, transfers from = %d",
3716 _global_transfers_to,_global_transfers_from);
3717 gclog_or_tty->print_cr(" Regions: claimed = %d", _regions_claimed);
3718 gclog_or_tty->print_cr(" SATB buffers: processed = %d", _satb_buffers_processed);
3719 gclog_or_tty->print_cr(" Steals: attempts = %d, successes = %d",
3720 _steal_attempts, _steals);
3721 gclog_or_tty->print_cr(" Aborted: %d, due to", _aborted);
3722 gclog_or_tty->print_cr(" overflow: %d, global abort: %d, yield: %d",
3723 _aborted_overflow, _aborted_cm_aborted, _aborted_yield);
3724 gclog_or_tty->print_cr(" time out: %d, SATB: %d, termination: %d",
3725 _aborted_timed_out, _aborted_satb, _aborted_termination);
3726 #endif // _MARKING_STATS_
3727 }
3728
3729 /*****************************************************************************
3730
3731 The do_marking_step(time_target_ms) method is the building block
3732 of the parallel marking framework. It can be called in parallel
3733 with other invocations of do_marking_step() on different tasks
3734 (but only one per task, obviously) and concurrently with the
3735 mutator threads, or during remark, hence it eliminates the need
3736 for two versions of the code. When called during remark, it will
3737 pick up from where the task left off during the concurrent marking
3738 phase. Interestingly, tasks are also claimable during evacuation
3739 pauses too, since do_marking_step() ensures that it aborts before
3740 it needs to yield.
3741
3742 The data structures that is uses to do marking work are the
3743 following:
3744
3745 (1) Marking Bitmap. If there are gray objects that appear only
3746 on the bitmap (this happens either when dealing with an overflow
3747 or when the initial marking phase has simply marked the roots
3748 and didn't push them on the stack), then tasks claim heap
3749 regions whose bitmap they then scan to find gray objects. A
3750 global finger indicates where the end of the last claimed region
3751 is. A local finger indicates how far into the region a task has
3752 scanned. The two fingers are used to determine how to gray an
3753 object (i.e. whether simply marking it is OK, as it will be
3754 visited by a task in the future, or whether it needs to be also
3755 pushed on a stack).
3756
3757 (2) Local Queue. The local queue of the task which is accessed
3758 reasonably efficiently by the task. Other tasks can steal from
3759 it when they run out of work. Throughout the marking phase, a
3760 task attempts to keep its local queue short but not totally
3761 empty, so that entries are available for stealing by other
3762 tasks. Only when there is no more work, a task will totally
3763 drain its local queue.
3764
3765 (3) Global Mark Stack. This handles local queue overflow. During
3766 marking only sets of entries are moved between it and the local
3767 queues, as access to it requires a mutex and more fine-grain
3768 interaction with it which might cause contention. If it
3769 overflows, then the marking phase should restart and iterate
3770 over the bitmap to identify gray objects. Throughout the marking
3771 phase, tasks attempt to keep the global mark stack at a small
3772 length but not totally empty, so that entries are available for
3773 popping by other tasks. Only when there is no more work, tasks
3774 will totally drain the global mark stack.
3775
3776 (4) SATB Buffer Queue. This is where completed SATB buffers are
3777 made available. Buffers are regularly removed from this queue
3778 and scanned for roots, so that the queue doesn't get too
3779 long. During remark, all completed buffers are processed, as
3780 well as the filled in parts of any uncompleted buffers.
3781
3782 The do_marking_step() method tries to abort when the time target
3783 has been reached. There are a few other cases when the
3784 do_marking_step() method also aborts:
3785
3786 (1) When the marking phase has been aborted (after a Full GC).
3787
3788 (2) When a global overflow (on the global stack) has been
3789 triggered. Before the task aborts, it will actually sync up with
3790 the other tasks to ensure that all the marking data structures
3791 (local queues, stacks, fingers etc.) are re-initialised so that
3792 when do_marking_step() completes, the marking phase can
3793 immediately restart.
3794
3795 (3) When enough completed SATB buffers are available. The
3796 do_marking_step() method only tries to drain SATB buffers right
3797 at the beginning. So, if enough buffers are available, the
3798 marking step aborts and the SATB buffers are processed at
3799 the beginning of the next invocation.
3800
3801 (4) To yield. when we have to yield then we abort and yield
3802 right at the end of do_marking_step(). This saves us from a lot
3803 of hassle as, by yielding we might allow a Full GC. If this
3804 happens then objects will be compacted underneath our feet, the
3805 heap might shrink, etc. We save checking for this by just
3806 aborting and doing the yield right at the end.
3807
3808 From the above it follows that the do_marking_step() method should
3809 be called in a loop (or, otherwise, regularly) until it completes.
3810
3811 If a marking step completes without its has_aborted() flag being
3812 true, it means it has completed the current marking phase (and
3813 also all other marking tasks have done so and have all synced up).
3814
3815 A method called regular_clock_call() is invoked "regularly" (in
3816 sub ms intervals) throughout marking. It is this clock method that
3817 checks all the abort conditions which were mentioned above and
3818 decides when the task should abort. A work-based scheme is used to
3819 trigger this clock method: when the number of object words the
3820 marking phase has scanned or the number of references the marking
3821 phase has visited reach a given limit. Additional invocations to
3822 the method clock have been planted in a few other strategic places
3823 too. The initial reason for the clock method was to avoid calling
3824 vtime too regularly, as it is quite expensive. So, once it was in
3825 place, it was natural to piggy-back all the other conditions on it
3826 too and not constantly check them throughout the code.
3827
3828 *****************************************************************************/
3829
3830 void CMTask::do_marking_step(double time_target_ms,
3831 bool do_stealing,
3832 bool do_termination) {
3833 assert(time_target_ms >= 1.0, "minimum granularity is 1ms");
3834 assert(concurrent() == _cm->concurrent(), "they should be the same");
3835
3836 G1CollectorPolicy* g1_policy = _g1h->g1_policy();
3837 assert(_task_queues != NULL, "invariant");
3838 assert(_task_queue != NULL, "invariant");
3839 assert(_task_queues->queue(_task_id) == _task_queue, "invariant");
3840
3841 assert(!_claimed,
3842 "only one thread should claim this task at any one time");
3843
3844 // OK, this doesn't safeguard again all possible scenarios, as it is
3845 // possible for two threads to set the _claimed flag at the same
3846 // time. But it is only for debugging purposes anyway and it will
3847 // catch most problems.
3848 _claimed = true;
3849
3850 _start_time_ms = os::elapsedVTime() * 1000.0;
3851 statsOnly( _interval_start_time_ms = _start_time_ms );
3852
3853 double diff_prediction_ms =
3854 g1_policy->get_new_prediction(&_marking_step_diffs_ms);
3855 _time_target_ms = time_target_ms - diff_prediction_ms;
3856
3857 // set up the variables that are used in the work-based scheme to
3858 // call the regular clock method
3859 _words_scanned = 0;
3860 _refs_reached = 0;
3861 recalculate_limits();
3862
3863 // clear all flags
3864 clear_has_aborted();
3865 _has_timed_out = false;
3866 _draining_satb_buffers = false;
3867
3868 ++_calls;
3869
3870 if (_cm->verbose_low()) {
3871 gclog_or_tty->print_cr("[%d] >>>>>>>>>> START, call = %d, "
3872 "target = %1.2lfms >>>>>>>>>>",
3873 _task_id, _calls, _time_target_ms);
3874 }
3875
3876 // Set up the bitmap and oop closures. Anything that uses them is
3877 // eventually called from this method, so it is OK to allocate these
3878 // statically.
3879 CMBitMapClosure bitmap_closure(this, _cm, _nextMarkBitMap);
3880 G1CMOopClosure cm_oop_closure(_g1h, _cm, this);
3881 set_cm_oop_closure(&cm_oop_closure);
3882
3883 if (_cm->has_overflown()) {
3884 // This can happen if the mark stack overflows during a GC pause
3885 // and this task, after a yield point, restarts. We have to abort
3886 // as we need to get into the overflow protocol which happens
3887 // right at the end of this task.
3888 set_has_aborted();
3889 }
3890
3891 // First drain any available SATB buffers. After this, we will not
3892 // look at SATB buffers before the next invocation of this method.
3893 // If enough completed SATB buffers are queued up, the regular clock
3894 // will abort this task so that it restarts.
3895 drain_satb_buffers();
3896 // ...then partially drain the local queue and the global stack
3897 drain_local_queue(true);
3898 drain_global_stack(true);
3899
3900 do {
3901 if (!has_aborted() && _curr_region != NULL) {
3902 // This means that we're already holding on to a region.
3903 assert(_finger != NULL, "if region is not NULL, then the finger "
3904 "should not be NULL either");
3905
3906 // We might have restarted this task after an evacuation pause
3907 // which might have evacuated the region we're holding on to
3908 // underneath our feet. Let's read its limit again to make sure
3909 // that we do not iterate over a region of the heap that
3910 // contains garbage (update_region_limit() will also move
3911 // _finger to the start of the region if it is found empty).
3912 update_region_limit();
3913 // We will start from _finger not from the start of the region,
3914 // as we might be restarting this task after aborting half-way
3915 // through scanning this region. In this case, _finger points to
3916 // the address where we last found a marked object. If this is a
3917 // fresh region, _finger points to start().
3918 MemRegion mr = MemRegion(_finger, _region_limit);
3919
3920 if (_cm->verbose_low()) {
3921 gclog_or_tty->print_cr("[%d] we're scanning part "
3922 "["PTR_FORMAT", "PTR_FORMAT") "
3923 "of region "PTR_FORMAT,
3924 _task_id, _finger, _region_limit, _curr_region);
3925 }
3926
3927 // Let's iterate over the bitmap of the part of the
3928 // region that is left.
3929 if (mr.is_empty() || _nextMarkBitMap->iterate(&bitmap_closure, mr)) {
3930 // We successfully completed iterating over the region. Now,
3931 // let's give up the region.
3932 giveup_current_region();
3933 regular_clock_call();
3934 } else {
3935 assert(has_aborted(), "currently the only way to do so");
3936 // The only way to abort the bitmap iteration is to return
3937 // false from the do_bit() method. However, inside the
3938 // do_bit() method we move the _finger to point to the
3939 // object currently being looked at. So, if we bail out, we
3940 // have definitely set _finger to something non-null.
3941 assert(_finger != NULL, "invariant");
3942
3943 // Region iteration was actually aborted. So now _finger
3944 // points to the address of the object we last scanned. If we
3945 // leave it there, when we restart this task, we will rescan
3946 // the object. It is easy to avoid this. We move the finger by
3947 // enough to point to the next possible object header (the
3948 // bitmap knows by how much we need to move it as it knows its
3949 // granularity).
3950 assert(_finger < _region_limit, "invariant");
3951 HeapWord* new_finger = _nextMarkBitMap->nextWord(_finger);
3952 // Check if bitmap iteration was aborted while scanning the last object
3953 if (new_finger >= _region_limit) {
3954 giveup_current_region();
3955 } else {
3956 move_finger_to(new_finger);
3957 }
3958 }
3959 }
3960 // At this point we have either completed iterating over the
3961 // region we were holding on to, or we have aborted.
3962
3963 // We then partially drain the local queue and the global stack.
3964 // (Do we really need this?)
3965 drain_local_queue(true);
3966 drain_global_stack(true);
3967
3968 // Read the note on the claim_region() method on why it might
3969 // return NULL with potentially more regions available for
3970 // claiming and why we have to check out_of_regions() to determine
3971 // whether we're done or not.
3972 while (!has_aborted() && _curr_region == NULL && !_cm->out_of_regions()) {
3973 // We are going to try to claim a new region. We should have
3974 // given up on the previous one.
3975 // Separated the asserts so that we know which one fires.
3976 assert(_curr_region == NULL, "invariant");
3977 assert(_finger == NULL, "invariant");
3978 assert(_region_limit == NULL, "invariant");
3979 if (_cm->verbose_low()) {
3980 gclog_or_tty->print_cr("[%d] trying to claim a new region", _task_id);
3981 }
3982 HeapRegion* claimed_region = _cm->claim_region(_task_id);
3983 if (claimed_region != NULL) {
3984 // Yes, we managed to claim one
3985 statsOnly( ++_regions_claimed );
3986
3987 if (_cm->verbose_low()) {
3988 gclog_or_tty->print_cr("[%d] we successfully claimed "
3989 "region "PTR_FORMAT,
3990 _task_id, claimed_region);
3991 }
3992
3993 setup_for_region(claimed_region);
3994 assert(_curr_region == claimed_region, "invariant");
3995 }
3996 // It is important to call the regular clock here. It might take
3997 // a while to claim a region if, for example, we hit a large
3998 // block of empty regions. So we need to call the regular clock
3999 // method once round the loop to make sure it's called
4000 // frequently enough.
4001 regular_clock_call();
4002 }
4003
4004 if (!has_aborted() && _curr_region == NULL) {
4005 assert(_cm->out_of_regions(),
4006 "at this point we should be out of regions");
4007 }
4008 } while ( _curr_region != NULL && !has_aborted());
4009
4010 if (!has_aborted()) {
4011 // We cannot check whether the global stack is empty, since other
4012 // tasks might be pushing objects to it concurrently.
4013 assert(_cm->out_of_regions(),
4014 "at this point we should be out of regions");
4015
4016 if (_cm->verbose_low()) {
4017 gclog_or_tty->print_cr("[%d] all regions claimed", _task_id);
4018 }
4019
4020 // Try to reduce the number of available SATB buffers so that
4021 // remark has less work to do.
4022 drain_satb_buffers();
4023 }
4024
4025 // Since we've done everything else, we can now totally drain the
4026 // local queue and global stack.
4027 drain_local_queue(false);
4028 drain_global_stack(false);
4029
4030 // Attempt at work stealing from other task's queues.
4031 if (do_stealing && !has_aborted()) {
4032 // We have not aborted. This means that we have finished all that
4033 // we could. Let's try to do some stealing...
4034
4035 // We cannot check whether the global stack is empty, since other
4036 // tasks might be pushing objects to it concurrently.
4037 assert(_cm->out_of_regions() && _task_queue->size() == 0,
4038 "only way to reach here");
4039
4040 if (_cm->verbose_low()) {
4041 gclog_or_tty->print_cr("[%d] starting to steal", _task_id);
4042 }
4043
4044 while (!has_aborted()) {
4045 oop obj;
4046 statsOnly( ++_steal_attempts );
4047
4048 if (_cm->try_stealing(_task_id, &_hash_seed, obj)) {
4049 if (_cm->verbose_medium()) {
4050 gclog_or_tty->print_cr("[%d] stolen "PTR_FORMAT" successfully",
4051 _task_id, (void*) obj);
4052 }
4053
4054 statsOnly( ++_steals );
4055
4056 assert(_nextMarkBitMap->isMarked((HeapWord*) obj),
4057 "any stolen object should be marked");
4058 scan_object(obj);
4059
4060 // And since we're towards the end, let's totally drain the
4061 // local queue and global stack.
4062 drain_local_queue(false);
4063 drain_global_stack(false);
4064 } else {
4065 break;
4066 }
4067 }
4068 }
4069
4070 // If we are about to wrap up and go into termination, check if we
4071 // should raise the overflow flag.
4072 if (do_termination && !has_aborted()) {
4073 if (_cm->force_overflow()->should_force()) {
4074 _cm->set_has_overflown();
4075 regular_clock_call();
4076 }
4077 }
4078
4079 // We still haven't aborted. Now, let's try to get into the
4080 // termination protocol.
4081 if (do_termination && !has_aborted()) {
4082 // We cannot check whether the global stack is empty, since other
4083 // tasks might be concurrently pushing objects on it.
4084 // Separated the asserts so that we know which one fires.
4085 assert(_cm->out_of_regions(), "only way to reach here");
4086 assert(_task_queue->size() == 0, "only way to reach here");
4087
4088 if (_cm->verbose_low()) {
4089 gclog_or_tty->print_cr("[%d] starting termination protocol", _task_id);
4090 }
4091
4092 _termination_start_time_ms = os::elapsedVTime() * 1000.0;
4093 // The CMTask class also extends the TerminatorTerminator class,
4094 // hence its should_exit_termination() method will also decide
4095 // whether to exit the termination protocol or not.
4096 bool finished = _cm->terminator()->offer_termination(this);
4097 double termination_end_time_ms = os::elapsedVTime() * 1000.0;
4098 _termination_time_ms +=
4099 termination_end_time_ms - _termination_start_time_ms;
4100
4101 if (finished) {
4102 // We're all done.
4103
4104 if (_task_id == 0) {
4105 // let's allow task 0 to do this
4106 if (concurrent()) {
4107 assert(_cm->concurrent_marking_in_progress(), "invariant");
4108 // we need to set this to false before the next
4109 // safepoint. This way we ensure that the marking phase
4110 // doesn't observe any more heap expansions.
4111 _cm->clear_concurrent_marking_in_progress();
4112 }
4113 }
4114
4115 // We can now guarantee that the global stack is empty, since
4116 // all other tasks have finished. We separated the guarantees so
4117 // that, if a condition is false, we can immediately find out
4118 // which one.
4119 guarantee(_cm->out_of_regions(), "only way to reach here");
4120 guarantee(_cm->mark_stack_empty(), "only way to reach here");
4121 guarantee(_task_queue->size() == 0, "only way to reach here");
4122 guarantee(!_cm->has_overflown(), "only way to reach here");
4123 guarantee(!_cm->mark_stack_overflow(), "only way to reach here");
4124
4125 if (_cm->verbose_low()) {
4126 gclog_or_tty->print_cr("[%d] all tasks terminated", _task_id);
4127 }
4128 } else {
4129 // Apparently there's more work to do. Let's abort this task. It
4130 // will restart it and we can hopefully find more things to do.
4131
4132 if (_cm->verbose_low()) {
4133 gclog_or_tty->print_cr("[%d] apparently there is more work to do",
4134 _task_id);
4135 }
4136
4137 set_has_aborted();
4138 statsOnly( ++_aborted_termination );
4139 }
4140 }
4141
4142 // Mainly for debugging purposes to make sure that a pointer to the
4143 // closure which was statically allocated in this frame doesn't
4144 // escape it by accident.
4145 set_cm_oop_closure(NULL);
4146 double end_time_ms = os::elapsedVTime() * 1000.0;
4147 double elapsed_time_ms = end_time_ms - _start_time_ms;
4148 // Update the step history.
4149 _step_times_ms.add(elapsed_time_ms);
4150
4151 if (has_aborted()) {
4152 // The task was aborted for some reason.
4153
4154 statsOnly( ++_aborted );
4155
4156 if (_has_timed_out) {
4157 double diff_ms = elapsed_time_ms - _time_target_ms;
4158 // Keep statistics of how well we did with respect to hitting
4159 // our target only if we actually timed out (if we aborted for
4160 // other reasons, then the results might get skewed).
4161 _marking_step_diffs_ms.add(diff_ms);
4162 }
4163
4164 if (_cm->has_overflown()) {
4165 // This is the interesting one. We aborted because a global
4166 // overflow was raised. This means we have to restart the
4167 // marking phase and start iterating over regions. However, in
4168 // order to do this we have to make sure that all tasks stop
4169 // what they are doing and re-initialise in a safe manner. We
4170 // will achieve this with the use of two barrier sync points.
4171
4172 if (_cm->verbose_low()) {
4173 gclog_or_tty->print_cr("[%d] detected overflow", _task_id);
4174 }
4175
4176 _cm->enter_first_sync_barrier(_task_id);
4177 // When we exit this sync barrier we know that all tasks have
4178 // stopped doing marking work. So, it's now safe to
4179 // re-initialise our data structures. At the end of this method,
4180 // task 0 will clear the global data structures.
4181
4182 statsOnly( ++_aborted_overflow );
4183
4184 // We clear the local state of this task...
4185 clear_region_fields();
4186
4187 // ...and enter the second barrier.
4188 _cm->enter_second_sync_barrier(_task_id);
4189 // At this point everything has bee re-initialised and we're
4190 // ready to restart.
4191 }
4192
4193 if (_cm->verbose_low()) {
4194 gclog_or_tty->print_cr("[%d] <<<<<<<<<< ABORTING, target = %1.2lfms, "
4195 "elapsed = %1.2lfms <<<<<<<<<<",
4196 _task_id, _time_target_ms, elapsed_time_ms);
4197 if (_cm->has_aborted()) {
4198 gclog_or_tty->print_cr("[%d] ========== MARKING ABORTED ==========",
4199 _task_id);
4200 }
4201 }
4202 } else {
4203 if (_cm->verbose_low()) {
4204 gclog_or_tty->print_cr("[%d] <<<<<<<<<< FINISHED, target = %1.2lfms, "
4205 "elapsed = %1.2lfms <<<<<<<<<<",
4206 _task_id, _time_target_ms, elapsed_time_ms);
4207 }
4208 }
4209
4210 _claimed = false;
4211 }
4212
4213 CMTask::CMTask(int task_id,
4214 ConcurrentMark* cm,
4215 size_t* marked_bytes,
4216 BitMap* card_bm,
4217 CMTaskQueue* task_queue,
4218 CMTaskQueueSet* task_queues)
4219 : _g1h(G1CollectedHeap::heap()),
4220 _task_id(task_id), _cm(cm),
4221 _claimed(false),
4222 _nextMarkBitMap(NULL), _hash_seed(17),
4223 _task_queue(task_queue),
4224 _task_queues(task_queues),
4225 _cm_oop_closure(NULL),
4226 _marked_bytes_array(marked_bytes),
4227 _card_bm(card_bm) {
4228 guarantee(task_queue != NULL, "invariant");
4229 guarantee(task_queues != NULL, "invariant");
4230
4231 statsOnly( _clock_due_to_scanning = 0;
4232 _clock_due_to_marking = 0 );
4233
4234 _marking_step_diffs_ms.add(0.5);
4235 }
4236
4237 // These are formatting macros that are used below to ensure
4238 // consistent formatting. The *_H_* versions are used to format the
4239 // header for a particular value and they should be kept consistent
4240 // with the corresponding macro. Also note that most of the macros add
4241 // the necessary white space (as a prefix) which makes them a bit
4242 // easier to compose.
4243
4244 // All the output lines are prefixed with this string to be able to
4245 // identify them easily in a large log file.
4246 #define G1PPRL_LINE_PREFIX "###"
4247
4248 #define G1PPRL_ADDR_BASE_FORMAT " "PTR_FORMAT"-"PTR_FORMAT
4249 #ifdef _LP64
4250 #define G1PPRL_ADDR_BASE_H_FORMAT " %37s"
4251 #else // _LP64
4252 #define G1PPRL_ADDR_BASE_H_FORMAT " %21s"
4253 #endif // _LP64
4254
4255 // For per-region info
4256 #define G1PPRL_TYPE_FORMAT " %-4s"
4257 #define G1PPRL_TYPE_H_FORMAT " %4s"
4258 #define G1PPRL_BYTE_FORMAT " "SIZE_FORMAT_W(9)
4259 #define G1PPRL_BYTE_H_FORMAT " %9s"
4260 #define G1PPRL_DOUBLE_FORMAT " %14.1f"
4261 #define G1PPRL_DOUBLE_H_FORMAT " %14s"
4262
4263 // For summary info
4264 #define G1PPRL_SUM_ADDR_FORMAT(tag) " "tag":"G1PPRL_ADDR_BASE_FORMAT
4265 #define G1PPRL_SUM_BYTE_FORMAT(tag) " "tag": "SIZE_FORMAT
4266 #define G1PPRL_SUM_MB_FORMAT(tag) " "tag": %1.2f MB"
4267 #define G1PPRL_SUM_MB_PERC_FORMAT(tag) G1PPRL_SUM_MB_FORMAT(tag)" / %1.2f %%"
4268
4269 G1PrintRegionLivenessInfoClosure::
4270 G1PrintRegionLivenessInfoClosure(outputStream* out, const char* phase_name)
4271 : _out(out),
4272 _total_used_bytes(0), _total_capacity_bytes(0),
4273 _total_prev_live_bytes(0), _total_next_live_bytes(0),
4274 _hum_used_bytes(0), _hum_capacity_bytes(0),
4275 _hum_prev_live_bytes(0), _hum_next_live_bytes(0) {
4276 G1CollectedHeap* g1h = G1CollectedHeap::heap();
4277 MemRegion g1_committed = g1h->g1_committed();
4278 MemRegion g1_reserved = g1h->g1_reserved();
4279 double now = os::elapsedTime();
4280
4281 // Print the header of the output.
4282 _out->cr();
4283 _out->print_cr(G1PPRL_LINE_PREFIX" PHASE %s @ %1.3f", phase_name, now);
4284 _out->print_cr(G1PPRL_LINE_PREFIX" HEAP"
4285 G1PPRL_SUM_ADDR_FORMAT("committed")
4286 G1PPRL_SUM_ADDR_FORMAT("reserved")
4287 G1PPRL_SUM_BYTE_FORMAT("region-size"),
4288 g1_committed.start(), g1_committed.end(),
4289 g1_reserved.start(), g1_reserved.end(),
4290 HeapRegion::GrainBytes);
4291 _out->print_cr(G1PPRL_LINE_PREFIX);
4292 _out->print_cr(G1PPRL_LINE_PREFIX
4293 G1PPRL_TYPE_H_FORMAT
4294 G1PPRL_ADDR_BASE_H_FORMAT
4295 G1PPRL_BYTE_H_FORMAT
4296 G1PPRL_BYTE_H_FORMAT
4297 G1PPRL_BYTE_H_FORMAT
4298 G1PPRL_DOUBLE_H_FORMAT,
4299 "type", "address-range",
4300 "used", "prev-live", "next-live", "gc-eff");
4301 _out->print_cr(G1PPRL_LINE_PREFIX
4302 G1PPRL_TYPE_H_FORMAT
4303 G1PPRL_ADDR_BASE_H_FORMAT
4304 G1PPRL_BYTE_H_FORMAT
4305 G1PPRL_BYTE_H_FORMAT
4306 G1PPRL_BYTE_H_FORMAT
4307 G1PPRL_DOUBLE_H_FORMAT,
4308 "", "",
4309 "(bytes)", "(bytes)", "(bytes)", "(bytes/ms)");
4310 }
4311
4312 // It takes as a parameter a reference to one of the _hum_* fields, it
4313 // deduces the corresponding value for a region in a humongous region
4314 // series (either the region size, or what's left if the _hum_* field
4315 // is < the region size), and updates the _hum_* field accordingly.
4316 size_t G1PrintRegionLivenessInfoClosure::get_hum_bytes(size_t* hum_bytes) {
4317 size_t bytes = 0;
4318 // The > 0 check is to deal with the prev and next live bytes which
4319 // could be 0.
4320 if (*hum_bytes > 0) {
4321 bytes = MIN2(HeapRegion::GrainBytes, *hum_bytes);
4322 *hum_bytes -= bytes;
4323 }
4324 return bytes;
4325 }
4326
4327 // It deduces the values for a region in a humongous region series
4328 // from the _hum_* fields and updates those accordingly. It assumes
4329 // that that _hum_* fields have already been set up from the "starts
4330 // humongous" region and we visit the regions in address order.
4331 void G1PrintRegionLivenessInfoClosure::get_hum_bytes(size_t* used_bytes,
4332 size_t* capacity_bytes,
4333 size_t* prev_live_bytes,
4334 size_t* next_live_bytes) {
4335 assert(_hum_used_bytes > 0 && _hum_capacity_bytes > 0, "pre-condition");
4336 *used_bytes = get_hum_bytes(&_hum_used_bytes);
4337 *capacity_bytes = get_hum_bytes(&_hum_capacity_bytes);
4338 *prev_live_bytes = get_hum_bytes(&_hum_prev_live_bytes);
4339 *next_live_bytes = get_hum_bytes(&_hum_next_live_bytes);
4340 }
4341
4342 bool G1PrintRegionLivenessInfoClosure::doHeapRegion(HeapRegion* r) {
4343 const char* type = "";
4344 HeapWord* bottom = r->bottom();
4345 HeapWord* end = r->end();
4346 size_t capacity_bytes = r->capacity();
4347 size_t used_bytes = r->used();
4348 size_t prev_live_bytes = r->live_bytes();
4349 size_t next_live_bytes = r->next_live_bytes();
4350 double gc_eff = r->gc_efficiency();
4351 if (r->used() == 0) {
4352 type = "FREE";
4353 } else if (r->is_survivor()) {
4354 type = "SURV";
4355 } else if (r->is_young()) {
4356 type = "EDEN";
4357 } else if (r->startsHumongous()) {
4358 type = "HUMS";
4359
4360 assert(_hum_used_bytes == 0 && _hum_capacity_bytes == 0 &&
4361 _hum_prev_live_bytes == 0 && _hum_next_live_bytes == 0,
4362 "they should have been zeroed after the last time we used them");
4363 // Set up the _hum_* fields.
4364 _hum_capacity_bytes = capacity_bytes;
4365 _hum_used_bytes = used_bytes;
4366 _hum_prev_live_bytes = prev_live_bytes;
4367 _hum_next_live_bytes = next_live_bytes;
4368 get_hum_bytes(&used_bytes, &capacity_bytes,
4369 &prev_live_bytes, &next_live_bytes);
4370 end = bottom + HeapRegion::GrainWords;
4371 } else if (r->continuesHumongous()) {
4372 type = "HUMC";
4373 get_hum_bytes(&used_bytes, &capacity_bytes,
4374 &prev_live_bytes, &next_live_bytes);
4375 assert(end == bottom + HeapRegion::GrainWords, "invariant");
4376 } else {
4377 type = "OLD";
4378 }
4379
4380 _total_used_bytes += used_bytes;
4381 _total_capacity_bytes += capacity_bytes;
4382 _total_prev_live_bytes += prev_live_bytes;
4383 _total_next_live_bytes += next_live_bytes;
4384
4385 // Print a line for this particular region.
4386 _out->print_cr(G1PPRL_LINE_PREFIX
4387 G1PPRL_TYPE_FORMAT
4388 G1PPRL_ADDR_BASE_FORMAT
4389 G1PPRL_BYTE_FORMAT
4390 G1PPRL_BYTE_FORMAT
4391 G1PPRL_BYTE_FORMAT
4392 G1PPRL_DOUBLE_FORMAT,
4393 type, bottom, end,
4394 used_bytes, prev_live_bytes, next_live_bytes, gc_eff);
4395
4396 return false;
4397 }
4398
4399 G1PrintRegionLivenessInfoClosure::~G1PrintRegionLivenessInfoClosure() {
4400 // Print the footer of the output.
4401 _out->print_cr(G1PPRL_LINE_PREFIX);
4402 _out->print_cr(G1PPRL_LINE_PREFIX
4403 " SUMMARY"
4404 G1PPRL_SUM_MB_FORMAT("capacity")
4405 G1PPRL_SUM_MB_PERC_FORMAT("used")
4406 G1PPRL_SUM_MB_PERC_FORMAT("prev-live")
4407 G1PPRL_SUM_MB_PERC_FORMAT("next-live"),
4408 bytes_to_mb(_total_capacity_bytes),
4409 bytes_to_mb(_total_used_bytes),
4410 perc(_total_used_bytes, _total_capacity_bytes),
4411 bytes_to_mb(_total_prev_live_bytes),
4412 perc(_total_prev_live_bytes, _total_capacity_bytes),
4413 bytes_to_mb(_total_next_live_bytes),
4414 perc(_total_next_live_bytes, _total_capacity_bytes));
4415 _out->cr();
4416 }