1 /*
2 * Copyright (c) 2005, 2015, 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/stringTable.hpp"
27 #include "classfile/systemDictionary.hpp"
28 #include "code/codeCache.hpp"
29 #include "gc_implementation/parallelScavenge/gcTaskManager.hpp"
30 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.inline.hpp"
31 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
32 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
33 #include "gc_implementation/parallelScavenge/psCompactionManager.inline.hpp"
34 #include "gc_implementation/parallelScavenge/psMarkSweep.hpp"
35 #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp"
36 #include "gc_implementation/parallelScavenge/psOldGen.hpp"
37 #include "gc_implementation/parallelScavenge/psParallelCompact.inline.hpp"
38 #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
39 #include "gc_implementation/parallelScavenge/psScavenge.hpp"
40 #include "gc_implementation/parallelScavenge/psYoungGen.hpp"
41 #include "gc_implementation/shared/gcHeapSummary.hpp"
42 #include "gc_implementation/shared/gcTimer.hpp"
43 #include "gc_implementation/shared/gcTrace.hpp"
44 #include "gc_implementation/shared/gcTraceTime.hpp"
45 #include "gc_implementation/shared/isGCActiveMark.hpp"
46 #include "gc_implementation/shared/spaceDecorator.hpp"
47 #include "gc_interface/gcCause.hpp"
48 #include "memory/gcLocker.inline.hpp"
49 #include "memory/referencePolicy.hpp"
50 #include "memory/referenceProcessor.hpp"
51 #include "oops/instanceKlass.inline.hpp"
52 #include "oops/instanceMirrorKlass.inline.hpp"
53 #include "oops/methodData.hpp"
54 #include "oops/objArrayKlass.inline.hpp"
55 #include "oops/oop.inline.hpp"
56 #include "runtime/atomic.inline.hpp"
57 #include "runtime/fprofiler.hpp"
58 #include "runtime/safepoint.hpp"
59 #include "runtime/vmThread.hpp"
60 #include "services/management.hpp"
61 #include "services/memoryService.hpp"
62 #include "services/memTracker.hpp"
63 #include "utilities/events.hpp"
64 #include "utilities/stack.inline.hpp"
65
66 #include <math.h>
67
68 // All sizes are in HeapWords.
69 const size_t ParallelCompactData::Log2RegionSize = 16; // 64K words
70 const size_t ParallelCompactData::RegionSize = (size_t)1 << Log2RegionSize;
71 const size_t ParallelCompactData::RegionSizeBytes =
72 RegionSize << LogHeapWordSize;
73 const size_t ParallelCompactData::RegionSizeOffsetMask = RegionSize - 1;
74 const size_t ParallelCompactData::RegionAddrOffsetMask = RegionSizeBytes - 1;
75 const size_t ParallelCompactData::RegionAddrMask = ~RegionAddrOffsetMask;
76
77 const size_t ParallelCompactData::Log2BlockSize = 7; // 128 words
78 const size_t ParallelCompactData::BlockSize = (size_t)1 << Log2BlockSize;
79 const size_t ParallelCompactData::BlockSizeBytes =
80 BlockSize << LogHeapWordSize;
81 const size_t ParallelCompactData::BlockSizeOffsetMask = BlockSize - 1;
82 const size_t ParallelCompactData::BlockAddrOffsetMask = BlockSizeBytes - 1;
83 const size_t ParallelCompactData::BlockAddrMask = ~BlockAddrOffsetMask;
84
85 const size_t ParallelCompactData::BlocksPerRegion = RegionSize / BlockSize;
86 const size_t ParallelCompactData::Log2BlocksPerRegion =
87 Log2RegionSize - Log2BlockSize;
88
89 const ParallelCompactData::RegionData::region_sz_t
90 ParallelCompactData::RegionData::dc_shift = 27;
91
92 const ParallelCompactData::RegionData::region_sz_t
93 ParallelCompactData::RegionData::dc_mask = ~0U << dc_shift;
94
95 const ParallelCompactData::RegionData::region_sz_t
96 ParallelCompactData::RegionData::dc_one = 0x1U << dc_shift;
97
98 const ParallelCompactData::RegionData::region_sz_t
99 ParallelCompactData::RegionData::los_mask = ~dc_mask;
100
101 const ParallelCompactData::RegionData::region_sz_t
102 ParallelCompactData::RegionData::dc_claimed = 0x8U << dc_shift;
103
104 const ParallelCompactData::RegionData::region_sz_t
105 ParallelCompactData::RegionData::dc_completed = 0xcU << dc_shift;
106
107 SpaceInfo PSParallelCompact::_space_info[PSParallelCompact::last_space_id];
108 bool PSParallelCompact::_print_phases = false;
109
110 ReferenceProcessor* PSParallelCompact::_ref_processor = NULL;
111
112 double PSParallelCompact::_dwl_mean;
113 double PSParallelCompact::_dwl_std_dev;
114 double PSParallelCompact::_dwl_first_term;
115 double PSParallelCompact::_dwl_adjustment;
116 #ifdef ASSERT
117 bool PSParallelCompact::_dwl_initialized = false;
118 #endif // #ifdef ASSERT
119
120 void SplitInfo::record(size_t src_region_idx, size_t partial_obj_size,
121 HeapWord* destination)
122 {
123 assert(src_region_idx != 0, "invalid src_region_idx");
124 assert(partial_obj_size != 0, "invalid partial_obj_size argument");
125 assert(destination != NULL, "invalid destination argument");
126
127 _src_region_idx = src_region_idx;
128 _partial_obj_size = partial_obj_size;
129 _destination = destination;
130
131 // These fields may not be updated below, so make sure they're clear.
132 assert(_dest_region_addr == NULL, "should have been cleared");
133 assert(_first_src_addr == NULL, "should have been cleared");
134
135 // Determine the number of destination regions for the partial object.
136 HeapWord* const last_word = destination + partial_obj_size - 1;
137 const ParallelCompactData& sd = PSParallelCompact::summary_data();
138 HeapWord* const beg_region_addr = sd.region_align_down(destination);
139 HeapWord* const end_region_addr = sd.region_align_down(last_word);
140
141 if (beg_region_addr == end_region_addr) {
142 // One destination region.
143 _destination_count = 1;
144 if (end_region_addr == destination) {
145 // The destination falls on a region boundary, thus the first word of the
146 // partial object will be the first word copied to the destination region.
147 _dest_region_addr = end_region_addr;
148 _first_src_addr = sd.region_to_addr(src_region_idx);
149 }
150 } else {
151 // Two destination regions. When copied, the partial object will cross a
152 // destination region boundary, so a word somewhere within the partial
153 // object will be the first word copied to the second destination region.
154 _destination_count = 2;
155 _dest_region_addr = end_region_addr;
156 const size_t ofs = pointer_delta(end_region_addr, destination);
157 assert(ofs < _partial_obj_size, "sanity");
158 _first_src_addr = sd.region_to_addr(src_region_idx) + ofs;
159 }
160 }
161
162 void SplitInfo::clear()
163 {
164 _src_region_idx = 0;
165 _partial_obj_size = 0;
166 _destination = NULL;
167 _destination_count = 0;
168 _dest_region_addr = NULL;
169 _first_src_addr = NULL;
170 assert(!is_valid(), "sanity");
171 }
172
173 #ifdef ASSERT
174 void SplitInfo::verify_clear()
175 {
176 assert(_src_region_idx == 0, "not clear");
177 assert(_partial_obj_size == 0, "not clear");
178 assert(_destination == NULL, "not clear");
179 assert(_destination_count == 0, "not clear");
180 assert(_dest_region_addr == NULL, "not clear");
181 assert(_first_src_addr == NULL, "not clear");
182 }
183 #endif // #ifdef ASSERT
184
185
186 void PSParallelCompact::print_on_error(outputStream* st) {
187 _mark_bitmap.print_on_error(st);
188 }
189
190 #ifndef PRODUCT
191 const char* PSParallelCompact::space_names[] = {
192 "old ", "eden", "from", "to "
193 };
194
195 void PSParallelCompact::print_region_ranges()
196 {
197 tty->print_cr("space bottom top end new_top");
198 tty->print_cr("------ ---------- ---------- ---------- ----------");
199
200 for (unsigned int id = 0; id < last_space_id; ++id) {
201 const MutableSpace* space = _space_info[id].space();
202 tty->print_cr("%u %s "
203 SIZE_FORMAT_W(10) " " SIZE_FORMAT_W(10) " "
204 SIZE_FORMAT_W(10) " " SIZE_FORMAT_W(10) " ",
205 id, space_names[id],
206 summary_data().addr_to_region_idx(space->bottom()),
207 summary_data().addr_to_region_idx(space->top()),
208 summary_data().addr_to_region_idx(space->end()),
209 summary_data().addr_to_region_idx(_space_info[id].new_top()));
210 }
211 }
212
213 void
214 print_generic_summary_region(size_t i, const ParallelCompactData::RegionData* c)
215 {
216 #define REGION_IDX_FORMAT SIZE_FORMAT_W(7)
217 #define REGION_DATA_FORMAT SIZE_FORMAT_W(5)
218
219 ParallelCompactData& sd = PSParallelCompact::summary_data();
220 size_t dci = c->destination() ? sd.addr_to_region_idx(c->destination()) : 0;
221 tty->print_cr(REGION_IDX_FORMAT " " PTR_FORMAT " "
222 REGION_IDX_FORMAT " " PTR_FORMAT " "
223 REGION_DATA_FORMAT " " REGION_DATA_FORMAT " "
224 REGION_DATA_FORMAT " " REGION_IDX_FORMAT " %d",
225 i, p2i(c->data_location()), dci, p2i(c->destination()),
226 c->partial_obj_size(), c->live_obj_size(),
227 c->data_size(), c->source_region(), c->destination_count());
228
229 #undef REGION_IDX_FORMAT
230 #undef REGION_DATA_FORMAT
231 }
232
233 void
234 print_generic_summary_data(ParallelCompactData& summary_data,
235 HeapWord* const beg_addr,
236 HeapWord* const end_addr)
237 {
238 size_t total_words = 0;
239 size_t i = summary_data.addr_to_region_idx(beg_addr);
240 const size_t last = summary_data.addr_to_region_idx(end_addr);
241 HeapWord* pdest = 0;
242
243 while (i <= last) {
244 ParallelCompactData::RegionData* c = summary_data.region(i);
245 if (c->data_size() != 0 || c->destination() != pdest) {
246 print_generic_summary_region(i, c);
247 total_words += c->data_size();
248 pdest = c->destination();
249 }
250 ++i;
251 }
252
253 tty->print_cr("summary_data_bytes=" SIZE_FORMAT, total_words * HeapWordSize);
254 }
255
256 void
257 print_generic_summary_data(ParallelCompactData& summary_data,
258 SpaceInfo* space_info)
259 {
260 for (unsigned int id = 0; id < PSParallelCompact::last_space_id; ++id) {
261 const MutableSpace* space = space_info[id].space();
262 print_generic_summary_data(summary_data, space->bottom(),
263 MAX2(space->top(), space_info[id].new_top()));
264 }
265 }
266
267 void
268 print_initial_summary_region(size_t i,
269 const ParallelCompactData::RegionData* c,
270 bool newline = true)
271 {
272 tty->print(SIZE_FORMAT_W(5) " " PTR_FORMAT " "
273 SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " "
274 SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " %d",
275 i, p2i(c->destination()),
276 c->partial_obj_size(), c->live_obj_size(),
277 c->data_size(), c->source_region(), c->destination_count());
278 if (newline) tty->cr();
279 }
280
281 void
282 print_initial_summary_data(ParallelCompactData& summary_data,
283 const MutableSpace* space) {
284 if (space->top() == space->bottom()) {
285 return;
286 }
287
288 const size_t region_size = ParallelCompactData::RegionSize;
289 typedef ParallelCompactData::RegionData RegionData;
290 HeapWord* const top_aligned_up = summary_data.region_align_up(space->top());
291 const size_t end_region = summary_data.addr_to_region_idx(top_aligned_up);
292 const RegionData* c = summary_data.region(end_region - 1);
293 HeapWord* end_addr = c->destination() + c->data_size();
294 const size_t live_in_space = pointer_delta(end_addr, space->bottom());
295
296 // Print (and count) the full regions at the beginning of the space.
297 size_t full_region_count = 0;
298 size_t i = summary_data.addr_to_region_idx(space->bottom());
299 while (i < end_region && summary_data.region(i)->data_size() == region_size) {
300 print_initial_summary_region(i, summary_data.region(i));
301 ++full_region_count;
302 ++i;
303 }
304
305 size_t live_to_right = live_in_space - full_region_count * region_size;
306
307 double max_reclaimed_ratio = 0.0;
308 size_t max_reclaimed_ratio_region = 0;
309 size_t max_dead_to_right = 0;
310 size_t max_live_to_right = 0;
311
312 // Print the 'reclaimed ratio' for regions while there is something live in
313 // the region or to the right of it. The remaining regions are empty (and
314 // uninteresting), and computing the ratio will result in division by 0.
315 while (i < end_region && live_to_right > 0) {
316 c = summary_data.region(i);
317 HeapWord* const region_addr = summary_data.region_to_addr(i);
318 const size_t used_to_right = pointer_delta(space->top(), region_addr);
319 const size_t dead_to_right = used_to_right - live_to_right;
320 const double reclaimed_ratio = double(dead_to_right) / live_to_right;
321
322 if (reclaimed_ratio > max_reclaimed_ratio) {
323 max_reclaimed_ratio = reclaimed_ratio;
324 max_reclaimed_ratio_region = i;
325 max_dead_to_right = dead_to_right;
326 max_live_to_right = live_to_right;
327 }
328
329 print_initial_summary_region(i, c, false);
330 tty->print_cr(" %12.10f " SIZE_FORMAT_W(10) " " SIZE_FORMAT_W(10),
331 reclaimed_ratio, dead_to_right, live_to_right);
332
333 live_to_right -= c->data_size();
334 ++i;
335 }
336
337 // Any remaining regions are empty. Print one more if there is one.
338 if (i < end_region) {
339 print_initial_summary_region(i, summary_data.region(i));
340 }
341
342 tty->print_cr("max: " SIZE_FORMAT_W(4) " d2r=" SIZE_FORMAT_W(10) " "
343 "l2r=" SIZE_FORMAT_W(10) " max_ratio=%14.12f",
344 max_reclaimed_ratio_region, max_dead_to_right,
345 max_live_to_right, max_reclaimed_ratio);
346 }
347
348 void
349 print_initial_summary_data(ParallelCompactData& summary_data,
350 SpaceInfo* space_info) {
351 unsigned int id = PSParallelCompact::old_space_id;
352 const MutableSpace* space;
353 do {
354 space = space_info[id].space();
355 print_initial_summary_data(summary_data, space);
356 } while (++id < PSParallelCompact::eden_space_id);
357
358 do {
359 space = space_info[id].space();
360 print_generic_summary_data(summary_data, space->bottom(), space->top());
361 } while (++id < PSParallelCompact::last_space_id);
362 }
363 #endif // #ifndef PRODUCT
364
365 #ifdef ASSERT
366 size_t add_obj_count;
367 size_t add_obj_size;
368 size_t mark_bitmap_count;
369 size_t mark_bitmap_size;
370 #endif // #ifdef ASSERT
371
372 ParallelCompactData::ParallelCompactData()
373 {
374 _region_start = 0;
375
376 _region_vspace = 0;
377 _reserved_byte_size = 0;
378 _region_data = 0;
379 _region_count = 0;
380
381 _block_vspace = 0;
382 _block_data = 0;
383 _block_count = 0;
384 }
385
386 bool ParallelCompactData::initialize(MemRegion covered_region)
387 {
388 _region_start = covered_region.start();
389 const size_t region_size = covered_region.word_size();
390 DEBUG_ONLY(_region_end = _region_start + region_size;)
391
392 assert(region_align_down(_region_start) == _region_start,
393 "region start not aligned");
394 assert((region_size & RegionSizeOffsetMask) == 0,
395 "region size not a multiple of RegionSize");
396
397 bool result = initialize_region_data(region_size) && initialize_block_data();
398 return result;
399 }
400
401 PSVirtualSpace*
402 ParallelCompactData::create_vspace(size_t count, size_t element_size)
403 {
404 const size_t raw_bytes = count * element_size;
405 const size_t page_sz = os::page_size_for_region_aligned(raw_bytes, 10);
406 const size_t granularity = os::vm_allocation_granularity();
407 _reserved_byte_size = align_size_up(raw_bytes, MAX2(page_sz, granularity));
408
409 const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 :
410 MAX2(page_sz, granularity);
411 ReservedSpace rs(_reserved_byte_size, rs_align, rs_align > 0);
412 os::trace_page_sizes("par compact", raw_bytes, raw_bytes, page_sz, rs.base(),
413 rs.size());
414
415 MemTracker::record_virtual_memory_type((address)rs.base(), mtGC);
416
417 PSVirtualSpace* vspace = new PSVirtualSpace(rs, page_sz);
418 if (vspace != 0) {
419 if (vspace->expand_by(_reserved_byte_size)) {
420 return vspace;
421 }
422 delete vspace;
423 // Release memory reserved in the space.
424 rs.release();
425 }
426
427 return 0;
428 }
429
430 bool ParallelCompactData::initialize_region_data(size_t region_size)
431 {
432 const size_t count = (region_size + RegionSizeOffsetMask) >> Log2RegionSize;
433 _region_vspace = create_vspace(count, sizeof(RegionData));
434 if (_region_vspace != 0) {
435 _region_data = (RegionData*)_region_vspace->reserved_low_addr();
436 _region_count = count;
437 return true;
438 }
439 return false;
440 }
441
442 bool ParallelCompactData::initialize_block_data()
443 {
444 assert(_region_count != 0, "region data must be initialized first");
445 const size_t count = _region_count << Log2BlocksPerRegion;
446 _block_vspace = create_vspace(count, sizeof(BlockData));
447 if (_block_vspace != 0) {
448 _block_data = (BlockData*)_block_vspace->reserved_low_addr();
449 _block_count = count;
450 return true;
451 }
452 return false;
453 }
454
455 void ParallelCompactData::clear()
456 {
457 memset(_region_data, 0, _region_vspace->committed_size());
458 memset(_block_data, 0, _block_vspace->committed_size());
459 }
460
461 void ParallelCompactData::clear_range(size_t beg_region, size_t end_region) {
462 assert(beg_region <= _region_count, "beg_region out of range");
463 assert(end_region <= _region_count, "end_region out of range");
464 assert(RegionSize % BlockSize == 0, "RegionSize not a multiple of BlockSize");
465
466 const size_t region_cnt = end_region - beg_region;
467 memset(_region_data + beg_region, 0, region_cnt * sizeof(RegionData));
468
469 const size_t beg_block = beg_region * BlocksPerRegion;
470 const size_t block_cnt = region_cnt * BlocksPerRegion;
471 memset(_block_data + beg_block, 0, block_cnt * sizeof(BlockData));
472 }
473
474 HeapWord* ParallelCompactData::partial_obj_end(size_t region_idx) const
475 {
476 const RegionData* cur_cp = region(region_idx);
477 const RegionData* const end_cp = region(region_count() - 1);
478
479 HeapWord* result = region_to_addr(region_idx);
480 if (cur_cp < end_cp) {
481 do {
482 result += cur_cp->partial_obj_size();
483 } while (cur_cp->partial_obj_size() == RegionSize && ++cur_cp < end_cp);
484 }
485 return result;
486 }
487
488 void ParallelCompactData::add_obj(HeapWord* addr, size_t len)
489 {
490 const size_t obj_ofs = pointer_delta(addr, _region_start);
491 const size_t beg_region = obj_ofs >> Log2RegionSize;
492 const size_t end_region = (obj_ofs + len - 1) >> Log2RegionSize;
493
494 DEBUG_ONLY(Atomic::inc_ptr(&add_obj_count);)
495 DEBUG_ONLY(Atomic::add_ptr(len, &add_obj_size);)
496
497 if (beg_region == end_region) {
498 // All in one region.
499 _region_data[beg_region].add_live_obj(len);
500 return;
501 }
502
503 // First region.
504 const size_t beg_ofs = region_offset(addr);
505 _region_data[beg_region].add_live_obj(RegionSize - beg_ofs);
506
507 Klass* klass = ((oop)addr)->klass();
508 // Middle regions--completely spanned by this object.
509 for (size_t region = beg_region + 1; region < end_region; ++region) {
510 _region_data[region].set_partial_obj_size(RegionSize);
511 _region_data[region].set_partial_obj_addr(addr);
512 }
513
514 // Last region.
515 const size_t end_ofs = region_offset(addr + len - 1);
516 _region_data[end_region].set_partial_obj_size(end_ofs + 1);
517 _region_data[end_region].set_partial_obj_addr(addr);
518 }
519
520 void
521 ParallelCompactData::summarize_dense_prefix(HeapWord* beg, HeapWord* end)
522 {
523 assert(region_offset(beg) == 0, "not RegionSize aligned");
524 assert(region_offset(end) == 0, "not RegionSize aligned");
525
526 size_t cur_region = addr_to_region_idx(beg);
527 const size_t end_region = addr_to_region_idx(end);
528 HeapWord* addr = beg;
529 while (cur_region < end_region) {
530 _region_data[cur_region].set_destination(addr);
531 _region_data[cur_region].set_destination_count(0);
532 _region_data[cur_region].set_source_region(cur_region);
533 _region_data[cur_region].set_data_location(addr);
534
535 // Update live_obj_size so the region appears completely full.
536 size_t live_size = RegionSize - _region_data[cur_region].partial_obj_size();
537 _region_data[cur_region].set_live_obj_size(live_size);
538
539 ++cur_region;
540 addr += RegionSize;
541 }
542 }
543
544 // Find the point at which a space can be split and, if necessary, record the
545 // split point.
546 //
547 // If the current src region (which overflowed the destination space) doesn't
548 // have a partial object, the split point is at the beginning of the current src
549 // region (an "easy" split, no extra bookkeeping required).
550 //
551 // If the current src region has a partial object, the split point is in the
552 // region where that partial object starts (call it the split_region). If
553 // split_region has a partial object, then the split point is just after that
554 // partial object (a "hard" split where we have to record the split data and
555 // zero the partial_obj_size field). With a "hard" split, we know that the
556 // partial_obj ends within split_region because the partial object that caused
557 // the overflow starts in split_region. If split_region doesn't have a partial
558 // obj, then the split is at the beginning of split_region (another "easy"
559 // split).
560 HeapWord*
561 ParallelCompactData::summarize_split_space(size_t src_region,
562 SplitInfo& split_info,
563 HeapWord* destination,
564 HeapWord* target_end,
565 HeapWord** target_next)
566 {
567 assert(destination <= target_end, "sanity");
568 assert(destination + _region_data[src_region].data_size() > target_end,
569 "region should not fit into target space");
570 assert(is_region_aligned(target_end), "sanity");
571
572 size_t split_region = src_region;
573 HeapWord* split_destination = destination;
574 size_t partial_obj_size = _region_data[src_region].partial_obj_size();
575
576 if (destination + partial_obj_size > target_end) {
577 // The split point is just after the partial object (if any) in the
578 // src_region that contains the start of the object that overflowed the
579 // destination space.
580 //
581 // Find the start of the "overflow" object and set split_region to the
582 // region containing it.
583 HeapWord* const overflow_obj = _region_data[src_region].partial_obj_addr();
584 split_region = addr_to_region_idx(overflow_obj);
585
586 // Clear the source_region field of all destination regions whose first word
587 // came from data after the split point (a non-null source_region field
588 // implies a region must be filled).
589 //
590 // An alternative to the simple loop below: clear during post_compact(),
591 // which uses memcpy instead of individual stores, and is easy to
592 // parallelize. (The downside is that it clears the entire RegionData
593 // object as opposed to just one field.)
594 //
595 // post_compact() would have to clear the summary data up to the highest
596 // address that was written during the summary phase, which would be
597 //
598 // max(top, max(new_top, clear_top))
599 //
600 // where clear_top is a new field in SpaceInfo. Would have to set clear_top
601 // to target_end.
602 const RegionData* const sr = region(split_region);
603 const size_t beg_idx =
604 addr_to_region_idx(region_align_up(sr->destination() +
605 sr->partial_obj_size()));
606 const size_t end_idx = addr_to_region_idx(target_end);
607
608 if (TraceParallelOldGCSummaryPhase) {
609 gclog_or_tty->print_cr("split: clearing source_region field in ["
610 SIZE_FORMAT ", " SIZE_FORMAT ")",
611 beg_idx, end_idx);
612 }
613 for (size_t idx = beg_idx; idx < end_idx; ++idx) {
614 _region_data[idx].set_source_region(0);
615 }
616
617 // Set split_destination and partial_obj_size to reflect the split region.
618 split_destination = sr->destination();
619 partial_obj_size = sr->partial_obj_size();
620 }
621
622 // The split is recorded only if a partial object extends onto the region.
623 if (partial_obj_size != 0) {
624 _region_data[split_region].set_partial_obj_size(0);
625 split_info.record(split_region, partial_obj_size, split_destination);
626 }
627
628 // Setup the continuation addresses.
629 *target_next = split_destination + partial_obj_size;
630 HeapWord* const source_next = region_to_addr(split_region) + partial_obj_size;
631
632 if (TraceParallelOldGCSummaryPhase) {
633 const char * split_type = partial_obj_size == 0 ? "easy" : "hard";
634 gclog_or_tty->print_cr("%s split: src=" PTR_FORMAT " src_c=" SIZE_FORMAT
635 " pos=" SIZE_FORMAT,
636 split_type, p2i(source_next), split_region,
637 partial_obj_size);
638 gclog_or_tty->print_cr("%s split: dst=" PTR_FORMAT " dst_c=" SIZE_FORMAT
639 " tn=" PTR_FORMAT,
640 split_type, p2i(split_destination),
641 addr_to_region_idx(split_destination),
642 p2i(*target_next));
643
644 if (partial_obj_size != 0) {
645 HeapWord* const po_beg = split_info.destination();
646 HeapWord* const po_end = po_beg + split_info.partial_obj_size();
647 gclog_or_tty->print_cr("%s split: "
648 "po_beg=" PTR_FORMAT " " SIZE_FORMAT " "
649 "po_end=" PTR_FORMAT " " SIZE_FORMAT,
650 split_type,
651 p2i(po_beg), addr_to_region_idx(po_beg),
652 p2i(po_end), addr_to_region_idx(po_end));
653 }
654 }
655
656 return source_next;
657 }
658
659 bool ParallelCompactData::summarize(SplitInfo& split_info,
660 HeapWord* source_beg, HeapWord* source_end,
661 HeapWord** source_next,
662 HeapWord* target_beg, HeapWord* target_end,
663 HeapWord** target_next)
664 {
665 if (TraceParallelOldGCSummaryPhase) {
666 HeapWord* const source_next_val = source_next == NULL ? NULL : *source_next;
667 tty->print_cr("sb=" PTR_FORMAT " se=" PTR_FORMAT " sn=" PTR_FORMAT
668 "tb=" PTR_FORMAT " te=" PTR_FORMAT " tn=" PTR_FORMAT,
669 p2i(source_beg), p2i(source_end), p2i(source_next_val),
670 p2i(target_beg), p2i(target_end), p2i(*target_next));
671 }
672
673 size_t cur_region = addr_to_region_idx(source_beg);
674 const size_t end_region = addr_to_region_idx(region_align_up(source_end));
675
676 HeapWord *dest_addr = target_beg;
677 while (cur_region < end_region) {
678 // The destination must be set even if the region has no data.
679 _region_data[cur_region].set_destination(dest_addr);
680
681 size_t words = _region_data[cur_region].data_size();
682 if (words > 0) {
683 // If cur_region does not fit entirely into the target space, find a point
684 // at which the source space can be 'split' so that part is copied to the
685 // target space and the rest is copied elsewhere.
686 if (dest_addr + words > target_end) {
687 assert(source_next != NULL, "source_next is NULL when splitting");
688 *source_next = summarize_split_space(cur_region, split_info, dest_addr,
689 target_end, target_next);
690 return false;
691 }
692
693 // Compute the destination_count for cur_region, and if necessary, update
694 // source_region for a destination region. The source_region field is
695 // updated if cur_region is the first (left-most) region to be copied to a
696 // destination region.
697 //
698 // The destination_count calculation is a bit subtle. A region that has
699 // data that compacts into itself does not count itself as a destination.
700 // This maintains the invariant that a zero count means the region is
701 // available and can be claimed and then filled.
702 uint destination_count = 0;
703 if (split_info.is_split(cur_region)) {
704 // The current region has been split: the partial object will be copied
705 // to one destination space and the remaining data will be copied to
706 // another destination space. Adjust the initial destination_count and,
707 // if necessary, set the source_region field if the partial object will
708 // cross a destination region boundary.
709 destination_count = split_info.destination_count();
710 if (destination_count == 2) {
711 size_t dest_idx = addr_to_region_idx(split_info.dest_region_addr());
712 _region_data[dest_idx].set_source_region(cur_region);
713 }
714 }
715
716 HeapWord* const last_addr = dest_addr + words - 1;
717 const size_t dest_region_1 = addr_to_region_idx(dest_addr);
718 const size_t dest_region_2 = addr_to_region_idx(last_addr);
719
720 // Initially assume that the destination regions will be the same and
721 // adjust the value below if necessary. Under this assumption, if
722 // cur_region == dest_region_2, then cur_region will be compacted
723 // completely into itself.
724 destination_count += cur_region == dest_region_2 ? 0 : 1;
725 if (dest_region_1 != dest_region_2) {
726 // Destination regions differ; adjust destination_count.
727 destination_count += 1;
728 // Data from cur_region will be copied to the start of dest_region_2.
729 _region_data[dest_region_2].set_source_region(cur_region);
730 } else if (region_offset(dest_addr) == 0) {
731 // Data from cur_region will be copied to the start of the destination
732 // region.
733 _region_data[dest_region_1].set_source_region(cur_region);
734 }
735
736 _region_data[cur_region].set_destination_count(destination_count);
737 _region_data[cur_region].set_data_location(region_to_addr(cur_region));
738 dest_addr += words;
739 }
740
741 ++cur_region;
742 }
743
744 *target_next = dest_addr;
745 return true;
746 }
747
748 HeapWord* ParallelCompactData::calc_new_pointer(HeapWord* addr) {
749 assert(addr != NULL, "Should detect NULL oop earlier");
750 assert(ParallelScavengeHeap::heap()->is_in(addr), "not in heap");
751 assert(PSParallelCompact::mark_bitmap()->is_marked(addr), "not marked");
752
753 // Region covering the object.
754 RegionData* const region_ptr = addr_to_region_ptr(addr);
755 HeapWord* result = region_ptr->destination();
756
757 // If the entire Region is live, the new location is region->destination + the
758 // offset of the object within in the Region.
759
760 // Run some performance tests to determine if this special case pays off. It
761 // is worth it for pointers into the dense prefix. If the optimization to
762 // avoid pointer updates in regions that only point to the dense prefix is
763 // ever implemented, this should be revisited.
764 if (region_ptr->data_size() == RegionSize) {
765 result += region_offset(addr);
766 return result;
767 }
768
769 // Otherwise, the new location is region->destination + block offset + the
770 // number of live words in the Block that are (a) to the left of addr and (b)
771 // due to objects that start in the Block.
772
773 // Fill in the block table if necessary. This is unsynchronized, so multiple
774 // threads may fill the block table for a region (harmless, since it is
775 // idempotent).
776 if (!region_ptr->blocks_filled()) {
777 PSParallelCompact::fill_blocks(addr_to_region_idx(addr));
778 region_ptr->set_blocks_filled();
779 }
780
781 HeapWord* const search_start = block_align_down(addr);
782 const size_t block_offset = addr_to_block_ptr(addr)->offset();
783
784 const ParMarkBitMap* bitmap = PSParallelCompact::mark_bitmap();
785 const size_t live = bitmap->live_words_in_range(search_start, oop(addr));
786 result += block_offset + live;
787 DEBUG_ONLY(PSParallelCompact::check_new_location(addr, result));
788 return result;
789 }
790
791 #ifdef ASSERT
792 void ParallelCompactData::verify_clear(const PSVirtualSpace* vspace)
793 {
794 const size_t* const beg = (const size_t*)vspace->committed_low_addr();
795 const size_t* const end = (const size_t*)vspace->committed_high_addr();
796 for (const size_t* p = beg; p < end; ++p) {
797 assert(*p == 0, "not zero");
798 }
799 }
800
801 void ParallelCompactData::verify_clear()
802 {
803 verify_clear(_region_vspace);
804 verify_clear(_block_vspace);
805 }
806 #endif // #ifdef ASSERT
807
808 STWGCTimer PSParallelCompact::_gc_timer;
809 ParallelOldTracer PSParallelCompact::_gc_tracer;
810 elapsedTimer PSParallelCompact::_accumulated_time;
811 unsigned int PSParallelCompact::_total_invocations = 0;
812 unsigned int PSParallelCompact::_maximum_compaction_gc_num = 0;
813 jlong PSParallelCompact::_time_of_last_gc = 0;
814 CollectorCounters* PSParallelCompact::_counters = NULL;
815 ParMarkBitMap PSParallelCompact::_mark_bitmap;
816 ParallelCompactData PSParallelCompact::_summary_data;
817
818 PSParallelCompact::IsAliveClosure PSParallelCompact::_is_alive_closure;
819
820 bool PSParallelCompact::IsAliveClosure::do_object_b(oop p) { return mark_bitmap()->is_marked(p); }
821
822 PSParallelCompact::AdjustPointerClosure PSParallelCompact::_adjust_pointer_closure;
823 PSParallelCompact::AdjustKlassClosure PSParallelCompact::_adjust_klass_closure;
824
825 void PSParallelCompact::FollowStackClosure::do_void() { _compaction_manager->follow_marking_stacks(); }
826
827 void PSParallelCompact::FollowKlassClosure::do_klass(Klass* klass) {
828 klass->oops_do(_mark_and_push_closure);
829 }
830 void PSParallelCompact::AdjustKlassClosure::do_klass(Klass* klass) {
831 klass->oops_do(&PSParallelCompact::_adjust_pointer_closure);
832 }
833
834 void PSParallelCompact::post_initialize() {
835 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
836 MemRegion mr = heap->reserved_region();
837 _ref_processor =
838 new ReferenceProcessor(mr, // span
839 ParallelRefProcEnabled && (ParallelGCThreads > 1), // mt processing
840 (int) ParallelGCThreads, // mt processing degree
841 true, // mt discovery
842 (int) ParallelGCThreads, // mt discovery degree
843 true, // atomic_discovery
844 &_is_alive_closure); // non-header is alive closure
845 _counters = new CollectorCounters("PSParallelCompact", 1);
846
847 // Initialize static fields in ParCompactionManager.
848 ParCompactionManager::initialize(mark_bitmap());
849 }
850
851 bool PSParallelCompact::initialize() {
852 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
853 MemRegion mr = heap->reserved_region();
854
855 // Was the old gen get allocated successfully?
856 if (!heap->old_gen()->is_allocated()) {
857 return false;
858 }
859
860 initialize_space_info();
861 initialize_dead_wood_limiter();
862
863 if (!_mark_bitmap.initialize(mr)) {
864 vm_shutdown_during_initialization(
865 err_msg("Unable to allocate " SIZE_FORMAT "KB bitmaps for parallel "
866 "garbage collection for the requested " SIZE_FORMAT "KB heap.",
867 _mark_bitmap.reserved_byte_size()/K, mr.byte_size()/K));
868 return false;
869 }
870
871 if (!_summary_data.initialize(mr)) {
872 vm_shutdown_during_initialization(
873 err_msg("Unable to allocate " SIZE_FORMAT "KB card tables for parallel "
874 "garbage collection for the requested " SIZE_FORMAT "KB heap.",
875 _summary_data.reserved_byte_size()/K, mr.byte_size()/K));
876 return false;
877 }
878
879 return true;
880 }
881
882 void PSParallelCompact::initialize_space_info()
883 {
884 memset(&_space_info, 0, sizeof(_space_info));
885
886 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
887 PSYoungGen* young_gen = heap->young_gen();
888
889 _space_info[old_space_id].set_space(heap->old_gen()->object_space());
890 _space_info[eden_space_id].set_space(young_gen->eden_space());
891 _space_info[from_space_id].set_space(young_gen->from_space());
892 _space_info[to_space_id].set_space(young_gen->to_space());
893
894 _space_info[old_space_id].set_start_array(heap->old_gen()->start_array());
895 }
896
897 void PSParallelCompact::initialize_dead_wood_limiter()
898 {
899 const size_t max = 100;
900 _dwl_mean = double(MIN2(ParallelOldDeadWoodLimiterMean, max)) / 100.0;
901 _dwl_std_dev = double(MIN2(ParallelOldDeadWoodLimiterStdDev, max)) / 100.0;
902 _dwl_first_term = 1.0 / (sqrt(2.0 * M_PI) * _dwl_std_dev);
903 DEBUG_ONLY(_dwl_initialized = true;)
904 _dwl_adjustment = normal_distribution(1.0);
905 }
906
907 // Simple class for storing info about the heap at the start of GC, to be used
908 // after GC for comparison/printing.
909 class PreGCValues {
910 public:
911 PreGCValues() { }
912 PreGCValues(ParallelScavengeHeap* heap) { fill(heap); }
913
914 void fill(ParallelScavengeHeap* heap) {
915 _heap_used = heap->used();
916 _young_gen_used = heap->young_gen()->used_in_bytes();
917 _old_gen_used = heap->old_gen()->used_in_bytes();
918 _metadata_used = MetaspaceAux::used_bytes();
919 };
920
921 size_t heap_used() const { return _heap_used; }
922 size_t young_gen_used() const { return _young_gen_used; }
923 size_t old_gen_used() const { return _old_gen_used; }
924 size_t metadata_used() const { return _metadata_used; }
925
926 private:
927 size_t _heap_used;
928 size_t _young_gen_used;
929 size_t _old_gen_used;
930 size_t _metadata_used;
931 };
932
933 void
934 PSParallelCompact::clear_data_covering_space(SpaceId id)
935 {
936 // At this point, top is the value before GC, new_top() is the value that will
937 // be set at the end of GC. The marking bitmap is cleared to top; nothing
938 // should be marked above top. The summary data is cleared to the larger of
939 // top & new_top.
940 MutableSpace* const space = _space_info[id].space();
941 HeapWord* const bot = space->bottom();
942 HeapWord* const top = space->top();
943 HeapWord* const max_top = MAX2(top, _space_info[id].new_top());
944
945 const idx_t beg_bit = _mark_bitmap.addr_to_bit(bot);
946 const idx_t end_bit = BitMap::word_align_up(_mark_bitmap.addr_to_bit(top));
947 _mark_bitmap.clear_range(beg_bit, end_bit);
948
949 const size_t beg_region = _summary_data.addr_to_region_idx(bot);
950 const size_t end_region =
951 _summary_data.addr_to_region_idx(_summary_data.region_align_up(max_top));
952 _summary_data.clear_range(beg_region, end_region);
953
954 // Clear the data used to 'split' regions.
955 SplitInfo& split_info = _space_info[id].split_info();
956 if (split_info.is_valid()) {
957 split_info.clear();
958 }
959 DEBUG_ONLY(split_info.verify_clear();)
960 }
961
962 void PSParallelCompact::pre_compact(PreGCValues* pre_gc_values)
963 {
964 // Update the from & to space pointers in space_info, since they are swapped
965 // at each young gen gc. Do the update unconditionally (even though a
966 // promotion failure does not swap spaces) because an unknown number of minor
967 // collections will have swapped the spaces an unknown number of times.
968 GCTraceTime tm("pre compact", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
969 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
970 _space_info[from_space_id].set_space(heap->young_gen()->from_space());
971 _space_info[to_space_id].set_space(heap->young_gen()->to_space());
972
973 pre_gc_values->fill(heap);
974
975 DEBUG_ONLY(add_obj_count = add_obj_size = 0;)
976 DEBUG_ONLY(mark_bitmap_count = mark_bitmap_size = 0;)
977
978 // Increment the invocation count
979 heap->increment_total_collections(true);
980
981 // We need to track unique mark sweep invocations as well.
982 _total_invocations++;
983
984 heap->print_heap_before_gc();
985 heap->trace_heap_before_gc(&_gc_tracer);
986
987 // Fill in TLABs
988 heap->accumulate_statistics_all_tlabs();
989 heap->ensure_parsability(true); // retire TLABs
990
991 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
992 HandleMark hm; // Discard invalid handles created during verification
993 Universe::verify(" VerifyBeforeGC:");
994 }
995
996 // Verify object start arrays
997 if (VerifyObjectStartArray &&
998 VerifyBeforeGC) {
999 heap->old_gen()->verify_object_start_array();
1000 }
1001
1002 DEBUG_ONLY(mark_bitmap()->verify_clear();)
1003 DEBUG_ONLY(summary_data().verify_clear();)
1004
1005 // Have worker threads release resources the next time they run a task.
1006 gc_task_manager()->release_all_resources();
1007 }
1008
1009 void PSParallelCompact::post_compact()
1010 {
1011 GCTraceTime tm("post compact", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
1012
1013 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
1014 // Clear the marking bitmap, summary data and split info.
1015 clear_data_covering_space(SpaceId(id));
1016 // Update top(). Must be done after clearing the bitmap and summary data.
1017 _space_info[id].publish_new_top();
1018 }
1019
1020 MutableSpace* const eden_space = _space_info[eden_space_id].space();
1021 MutableSpace* const from_space = _space_info[from_space_id].space();
1022 MutableSpace* const to_space = _space_info[to_space_id].space();
1023
1024 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
1025 bool eden_empty = eden_space->is_empty();
1026 if (!eden_empty) {
1027 eden_empty = absorb_live_data_from_eden(heap->size_policy(),
1028 heap->young_gen(), heap->old_gen());
1029 }
1030
1031 // Update heap occupancy information which is used as input to the soft ref
1032 // clearing policy at the next gc.
1033 Universe::update_heap_info_at_gc();
1034
1035 bool young_gen_empty = eden_empty && from_space->is_empty() &&
1036 to_space->is_empty();
1037
1038 ModRefBarrierSet* modBS = barrier_set_cast<ModRefBarrierSet>(heap->barrier_set());
1039 MemRegion old_mr = heap->old_gen()->reserved();
1040 if (young_gen_empty) {
1041 modBS->clear(MemRegion(old_mr.start(), old_mr.end()));
1042 } else {
1043 modBS->invalidate(MemRegion(old_mr.start(), old_mr.end()));
1044 }
1045
1046 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
1047 ClassLoaderDataGraph::purge();
1048 MetaspaceAux::verify_metrics();
1049
1050 CodeCache::gc_epilogue();
1051 JvmtiExport::gc_epilogue();
1052
1053 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
1054
1055 ref_processor()->enqueue_discovered_references(NULL);
1056
1057 if (ZapUnusedHeapArea) {
1058 heap->gen_mangle_unused_area();
1059 }
1060
1061 // Update time of last GC
1062 reset_millis_since_last_gc();
1063 }
1064
1065 HeapWord*
1066 PSParallelCompact::compute_dense_prefix_via_density(const SpaceId id,
1067 bool maximum_compaction)
1068 {
1069 const size_t region_size = ParallelCompactData::RegionSize;
1070 const ParallelCompactData& sd = summary_data();
1071
1072 const MutableSpace* const space = _space_info[id].space();
1073 HeapWord* const top_aligned_up = sd.region_align_up(space->top());
1074 const RegionData* const beg_cp = sd.addr_to_region_ptr(space->bottom());
1075 const RegionData* const end_cp = sd.addr_to_region_ptr(top_aligned_up);
1076
1077 // Skip full regions at the beginning of the space--they are necessarily part
1078 // of the dense prefix.
1079 size_t full_count = 0;
1080 const RegionData* cp;
1081 for (cp = beg_cp; cp < end_cp && cp->data_size() == region_size; ++cp) {
1082 ++full_count;
1083 }
1084
1085 assert(total_invocations() >= _maximum_compaction_gc_num, "sanity");
1086 const size_t gcs_since_max = total_invocations() - _maximum_compaction_gc_num;
1087 const bool interval_ended = gcs_since_max > HeapMaximumCompactionInterval;
1088 if (maximum_compaction || cp == end_cp || interval_ended) {
1089 _maximum_compaction_gc_num = total_invocations();
1090 return sd.region_to_addr(cp);
1091 }
1092
1093 HeapWord* const new_top = _space_info[id].new_top();
1094 const size_t space_live = pointer_delta(new_top, space->bottom());
1095 const size_t space_used = space->used_in_words();
1096 const size_t space_capacity = space->capacity_in_words();
1097
1098 const double cur_density = double(space_live) / space_capacity;
1099 const double deadwood_density =
1100 (1.0 - cur_density) * (1.0 - cur_density) * cur_density * cur_density;
1101 const size_t deadwood_goal = size_t(space_capacity * deadwood_density);
1102
1103 if (TraceParallelOldGCDensePrefix) {
1104 tty->print_cr("cur_dens=%5.3f dw_dens=%5.3f dw_goal=" SIZE_FORMAT,
1105 cur_density, deadwood_density, deadwood_goal);
1106 tty->print_cr("space_live=" SIZE_FORMAT " " "space_used=" SIZE_FORMAT " "
1107 "space_cap=" SIZE_FORMAT,
1108 space_live, space_used,
1109 space_capacity);
1110 }
1111
1112 // XXX - Use binary search?
1113 HeapWord* dense_prefix = sd.region_to_addr(cp);
1114 const RegionData* full_cp = cp;
1115 const RegionData* const top_cp = sd.addr_to_region_ptr(space->top() - 1);
1116 while (cp < end_cp) {
1117 HeapWord* region_destination = cp->destination();
1118 const size_t cur_deadwood = pointer_delta(dense_prefix, region_destination);
1119 if (TraceParallelOldGCDensePrefix && Verbose) {
1120 tty->print_cr("c#=" SIZE_FORMAT_W(4) " dst=" PTR_FORMAT " "
1121 "dp=" PTR_FORMAT " " "cdw=" SIZE_FORMAT_W(8),
1122 sd.region(cp), p2i(region_destination),
1123 p2i(dense_prefix), cur_deadwood);
1124 }
1125
1126 if (cur_deadwood >= deadwood_goal) {
1127 // Found the region that has the correct amount of deadwood to the left.
1128 // This typically occurs after crossing a fairly sparse set of regions, so
1129 // iterate backwards over those sparse regions, looking for the region
1130 // that has the lowest density of live objects 'to the right.'
1131 size_t space_to_left = sd.region(cp) * region_size;
1132 size_t live_to_left = space_to_left - cur_deadwood;
1133 size_t space_to_right = space_capacity - space_to_left;
1134 size_t live_to_right = space_live - live_to_left;
1135 double density_to_right = double(live_to_right) / space_to_right;
1136 while (cp > full_cp) {
1137 --cp;
1138 const size_t prev_region_live_to_right = live_to_right -
1139 cp->data_size();
1140 const size_t prev_region_space_to_right = space_to_right + region_size;
1141 double prev_region_density_to_right =
1142 double(prev_region_live_to_right) / prev_region_space_to_right;
1143 if (density_to_right <= prev_region_density_to_right) {
1144 return dense_prefix;
1145 }
1146 if (TraceParallelOldGCDensePrefix && Verbose) {
1147 tty->print_cr("backing up from c=" SIZE_FORMAT_W(4) " d2r=%10.8f "
1148 "pc_d2r=%10.8f", sd.region(cp), density_to_right,
1149 prev_region_density_to_right);
1150 }
1151 dense_prefix -= region_size;
1152 live_to_right = prev_region_live_to_right;
1153 space_to_right = prev_region_space_to_right;
1154 density_to_right = prev_region_density_to_right;
1155 }
1156 return dense_prefix;
1157 }
1158
1159 dense_prefix += region_size;
1160 ++cp;
1161 }
1162
1163 return dense_prefix;
1164 }
1165
1166 #ifndef PRODUCT
1167 void PSParallelCompact::print_dense_prefix_stats(const char* const algorithm,
1168 const SpaceId id,
1169 const bool maximum_compaction,
1170 HeapWord* const addr)
1171 {
1172 const size_t region_idx = summary_data().addr_to_region_idx(addr);
1173 RegionData* const cp = summary_data().region(region_idx);
1174 const MutableSpace* const space = _space_info[id].space();
1175 HeapWord* const new_top = _space_info[id].new_top();
1176
1177 const size_t space_live = pointer_delta(new_top, space->bottom());
1178 const size_t dead_to_left = pointer_delta(addr, cp->destination());
1179 const size_t space_cap = space->capacity_in_words();
1180 const double dead_to_left_pct = double(dead_to_left) / space_cap;
1181 const size_t live_to_right = new_top - cp->destination();
1182 const size_t dead_to_right = space->top() - addr - live_to_right;
1183
1184 tty->print_cr("%s=" PTR_FORMAT " dpc=" SIZE_FORMAT_W(5) " "
1185 "spl=" SIZE_FORMAT " "
1186 "d2l=" SIZE_FORMAT " d2l%%=%6.4f "
1187 "d2r=" SIZE_FORMAT " l2r=" SIZE_FORMAT
1188 " ratio=%10.8f",
1189 algorithm, p2i(addr), region_idx,
1190 space_live,
1191 dead_to_left, dead_to_left_pct,
1192 dead_to_right, live_to_right,
1193 double(dead_to_right) / live_to_right);
1194 }
1195 #endif // #ifndef PRODUCT
1196
1197 // Return a fraction indicating how much of the generation can be treated as
1198 // "dead wood" (i.e., not reclaimed). The function uses a normal distribution
1199 // based on the density of live objects in the generation to determine a limit,
1200 // which is then adjusted so the return value is min_percent when the density is
1201 // 1.
1202 //
1203 // The following table shows some return values for a different values of the
1204 // standard deviation (ParallelOldDeadWoodLimiterStdDev); the mean is 0.5 and
1205 // min_percent is 1.
1206 //
1207 // fraction allowed as dead wood
1208 // -----------------------------------------------------------------
1209 // density std_dev=70 std_dev=75 std_dev=80 std_dev=85 std_dev=90 std_dev=95
1210 // ------- ---------- ---------- ---------- ---------- ---------- ----------
1211 // 0.00000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000
1212 // 0.05000 0.03193096 0.02836880 0.02550828 0.02319280 0.02130337 0.01974941
1213 // 0.10000 0.05247504 0.04547452 0.03988045 0.03537016 0.03170171 0.02869272
1214 // 0.15000 0.07135702 0.06111390 0.05296419 0.04641639 0.04110601 0.03676066
1215 // 0.20000 0.08831616 0.07509618 0.06461766 0.05622444 0.04943437 0.04388975
1216 // 0.25000 0.10311208 0.08724696 0.07471205 0.06469760 0.05661313 0.05002313
1217 // 0.30000 0.11553050 0.09741183 0.08313394 0.07175114 0.06257797 0.05511132
1218 // 0.35000 0.12538832 0.10545958 0.08978741 0.07731366 0.06727491 0.05911289
1219 // 0.40000 0.13253818 0.11128511 0.09459590 0.08132834 0.07066107 0.06199500
1220 // 0.45000 0.13687208 0.11481163 0.09750361 0.08375387 0.07270534 0.06373386
1221 // 0.50000 0.13832410 0.11599237 0.09847664 0.08456518 0.07338887 0.06431510
1222 // 0.55000 0.13687208 0.11481163 0.09750361 0.08375387 0.07270534 0.06373386
1223 // 0.60000 0.13253818 0.11128511 0.09459590 0.08132834 0.07066107 0.06199500
1224 // 0.65000 0.12538832 0.10545958 0.08978741 0.07731366 0.06727491 0.05911289
1225 // 0.70000 0.11553050 0.09741183 0.08313394 0.07175114 0.06257797 0.05511132
1226 // 0.75000 0.10311208 0.08724696 0.07471205 0.06469760 0.05661313 0.05002313
1227 // 0.80000 0.08831616 0.07509618 0.06461766 0.05622444 0.04943437 0.04388975
1228 // 0.85000 0.07135702 0.06111390 0.05296419 0.04641639 0.04110601 0.03676066
1229 // 0.90000 0.05247504 0.04547452 0.03988045 0.03537016 0.03170171 0.02869272
1230 // 0.95000 0.03193096 0.02836880 0.02550828 0.02319280 0.02130337 0.01974941
1231 // 1.00000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000
1232
1233 double PSParallelCompact::dead_wood_limiter(double density, size_t min_percent)
1234 {
1235 assert(_dwl_initialized, "uninitialized");
1236
1237 // The raw limit is the value of the normal distribution at x = density.
1238 const double raw_limit = normal_distribution(density);
1239
1240 // Adjust the raw limit so it becomes the minimum when the density is 1.
1241 //
1242 // First subtract the adjustment value (which is simply the precomputed value
1243 // normal_distribution(1.0)); this yields a value of 0 when the density is 1.
1244 // Then add the minimum value, so the minimum is returned when the density is
1245 // 1. Finally, prevent negative values, which occur when the mean is not 0.5.
1246 const double min = double(min_percent) / 100.0;
1247 const double limit = raw_limit - _dwl_adjustment + min;
1248 return MAX2(limit, 0.0);
1249 }
1250
1251 ParallelCompactData::RegionData*
1252 PSParallelCompact::first_dead_space_region(const RegionData* beg,
1253 const RegionData* end)
1254 {
1255 const size_t region_size = ParallelCompactData::RegionSize;
1256 ParallelCompactData& sd = summary_data();
1257 size_t left = sd.region(beg);
1258 size_t right = end > beg ? sd.region(end) - 1 : left;
1259
1260 // Binary search.
1261 while (left < right) {
1262 // Equivalent to (left + right) / 2, but does not overflow.
1263 const size_t middle = left + (right - left) / 2;
1264 RegionData* const middle_ptr = sd.region(middle);
1265 HeapWord* const dest = middle_ptr->destination();
1266 HeapWord* const addr = sd.region_to_addr(middle);
1267 assert(dest != NULL, "sanity");
1268 assert(dest <= addr, "must move left");
1269
1270 if (middle > left && dest < addr) {
1271 right = middle - 1;
1272 } else if (middle < right && middle_ptr->data_size() == region_size) {
1273 left = middle + 1;
1274 } else {
1275 return middle_ptr;
1276 }
1277 }
1278 return sd.region(left);
1279 }
1280
1281 ParallelCompactData::RegionData*
1282 PSParallelCompact::dead_wood_limit_region(const RegionData* beg,
1283 const RegionData* end,
1284 size_t dead_words)
1285 {
1286 ParallelCompactData& sd = summary_data();
1287 size_t left = sd.region(beg);
1288 size_t right = end > beg ? sd.region(end) - 1 : left;
1289
1290 // Binary search.
1291 while (left < right) {
1292 // Equivalent to (left + right) / 2, but does not overflow.
1293 const size_t middle = left + (right - left) / 2;
1294 RegionData* const middle_ptr = sd.region(middle);
1295 HeapWord* const dest = middle_ptr->destination();
1296 HeapWord* const addr = sd.region_to_addr(middle);
1297 assert(dest != NULL, "sanity");
1298 assert(dest <= addr, "must move left");
1299
1300 const size_t dead_to_left = pointer_delta(addr, dest);
1301 if (middle > left && dead_to_left > dead_words) {
1302 right = middle - 1;
1303 } else if (middle < right && dead_to_left < dead_words) {
1304 left = middle + 1;
1305 } else {
1306 return middle_ptr;
1307 }
1308 }
1309 return sd.region(left);
1310 }
1311
1312 // The result is valid during the summary phase, after the initial summarization
1313 // of each space into itself, and before final summarization.
1314 inline double
1315 PSParallelCompact::reclaimed_ratio(const RegionData* const cp,
1316 HeapWord* const bottom,
1317 HeapWord* const top,
1318 HeapWord* const new_top)
1319 {
1320 ParallelCompactData& sd = summary_data();
1321
1322 assert(cp != NULL, "sanity");
1323 assert(bottom != NULL, "sanity");
1324 assert(top != NULL, "sanity");
1325 assert(new_top != NULL, "sanity");
1326 assert(top >= new_top, "summary data problem?");
1327 assert(new_top > bottom, "space is empty; should not be here");
1328 assert(new_top >= cp->destination(), "sanity");
1329 assert(top >= sd.region_to_addr(cp), "sanity");
1330
1331 HeapWord* const destination = cp->destination();
1332 const size_t dense_prefix_live = pointer_delta(destination, bottom);
1333 const size_t compacted_region_live = pointer_delta(new_top, destination);
1334 const size_t compacted_region_used = pointer_delta(top,
1335 sd.region_to_addr(cp));
1336 const size_t reclaimable = compacted_region_used - compacted_region_live;
1337
1338 const double divisor = dense_prefix_live + 1.25 * compacted_region_live;
1339 return double(reclaimable) / divisor;
1340 }
1341
1342 // Return the address of the end of the dense prefix, a.k.a. the start of the
1343 // compacted region. The address is always on a region boundary.
1344 //
1345 // Completely full regions at the left are skipped, since no compaction can
1346 // occur in those regions. Then the maximum amount of dead wood to allow is
1347 // computed, based on the density (amount live / capacity) of the generation;
1348 // the region with approximately that amount of dead space to the left is
1349 // identified as the limit region. Regions between the last completely full
1350 // region and the limit region are scanned and the one that has the best
1351 // (maximum) reclaimed_ratio() is selected.
1352 HeapWord*
1353 PSParallelCompact::compute_dense_prefix(const SpaceId id,
1354 bool maximum_compaction)
1355 {
1356 if (ParallelOldGCSplitALot) {
1357 if (_space_info[id].dense_prefix() != _space_info[id].space()->bottom()) {
1358 // The value was chosen to provoke splitting a young gen space; use it.
1359 return _space_info[id].dense_prefix();
1360 }
1361 }
1362
1363 const size_t region_size = ParallelCompactData::RegionSize;
1364 const ParallelCompactData& sd = summary_data();
1365
1366 const MutableSpace* const space = _space_info[id].space();
1367 HeapWord* const top = space->top();
1368 HeapWord* const top_aligned_up = sd.region_align_up(top);
1369 HeapWord* const new_top = _space_info[id].new_top();
1370 HeapWord* const new_top_aligned_up = sd.region_align_up(new_top);
1371 HeapWord* const bottom = space->bottom();
1372 const RegionData* const beg_cp = sd.addr_to_region_ptr(bottom);
1373 const RegionData* const top_cp = sd.addr_to_region_ptr(top_aligned_up);
1374 const RegionData* const new_top_cp =
1375 sd.addr_to_region_ptr(new_top_aligned_up);
1376
1377 // Skip full regions at the beginning of the space--they are necessarily part
1378 // of the dense prefix.
1379 const RegionData* const full_cp = first_dead_space_region(beg_cp, new_top_cp);
1380 assert(full_cp->destination() == sd.region_to_addr(full_cp) ||
1381 space->is_empty(), "no dead space allowed to the left");
1382 assert(full_cp->data_size() < region_size || full_cp == new_top_cp - 1,
1383 "region must have dead space");
1384
1385 // The gc number is saved whenever a maximum compaction is done, and used to
1386 // determine when the maximum compaction interval has expired. This avoids
1387 // successive max compactions for different reasons.
1388 assert(total_invocations() >= _maximum_compaction_gc_num, "sanity");
1389 const size_t gcs_since_max = total_invocations() - _maximum_compaction_gc_num;
1390 const bool interval_ended = gcs_since_max > HeapMaximumCompactionInterval ||
1391 total_invocations() == HeapFirstMaximumCompactionCount;
1392 if (maximum_compaction || full_cp == top_cp || interval_ended) {
1393 _maximum_compaction_gc_num = total_invocations();
1394 return sd.region_to_addr(full_cp);
1395 }
1396
1397 const size_t space_live = pointer_delta(new_top, bottom);
1398 const size_t space_used = space->used_in_words();
1399 const size_t space_capacity = space->capacity_in_words();
1400
1401 const double density = double(space_live) / double(space_capacity);
1402 const size_t min_percent_free = MarkSweepDeadRatio;
1403 const double limiter = dead_wood_limiter(density, min_percent_free);
1404 const size_t dead_wood_max = space_used - space_live;
1405 const size_t dead_wood_limit = MIN2(size_t(space_capacity * limiter),
1406 dead_wood_max);
1407
1408 if (TraceParallelOldGCDensePrefix) {
1409 tty->print_cr("space_live=" SIZE_FORMAT " " "space_used=" SIZE_FORMAT " "
1410 "space_cap=" SIZE_FORMAT,
1411 space_live, space_used,
1412 space_capacity);
1413 tty->print_cr("dead_wood_limiter(%6.4f, " SIZE_FORMAT ")=%6.4f "
1414 "dead_wood_max=" SIZE_FORMAT " dead_wood_limit=" SIZE_FORMAT,
1415 density, min_percent_free, limiter,
1416 dead_wood_max, dead_wood_limit);
1417 }
1418
1419 // Locate the region with the desired amount of dead space to the left.
1420 const RegionData* const limit_cp =
1421 dead_wood_limit_region(full_cp, top_cp, dead_wood_limit);
1422
1423 // Scan from the first region with dead space to the limit region and find the
1424 // one with the best (largest) reclaimed ratio.
1425 double best_ratio = 0.0;
1426 const RegionData* best_cp = full_cp;
1427 for (const RegionData* cp = full_cp; cp < limit_cp; ++cp) {
1428 double tmp_ratio = reclaimed_ratio(cp, bottom, top, new_top);
1429 if (tmp_ratio > best_ratio) {
1430 best_cp = cp;
1431 best_ratio = tmp_ratio;
1432 }
1433 }
1434
1435 #if 0
1436 // Something to consider: if the region with the best ratio is 'close to' the
1437 // first region w/free space, choose the first region with free space
1438 // ("first-free"). The first-free region is usually near the start of the
1439 // heap, which means we are copying most of the heap already, so copy a bit
1440 // more to get complete compaction.
1441 if (pointer_delta(best_cp, full_cp, sizeof(RegionData)) < 4) {
1442 _maximum_compaction_gc_num = total_invocations();
1443 best_cp = full_cp;
1444 }
1445 #endif // #if 0
1446
1447 return sd.region_to_addr(best_cp);
1448 }
1449
1450 #ifndef PRODUCT
1451 void
1452 PSParallelCompact::fill_with_live_objects(SpaceId id, HeapWord* const start,
1453 size_t words)
1454 {
1455 if (TraceParallelOldGCSummaryPhase) {
1456 tty->print_cr("fill_with_live_objects [" PTR_FORMAT " " PTR_FORMAT ") "
1457 SIZE_FORMAT, p2i(start), p2i(start + words), words);
1458 }
1459
1460 ObjectStartArray* const start_array = _space_info[id].start_array();
1461 CollectedHeap::fill_with_objects(start, words);
1462 for (HeapWord* p = start; p < start + words; p += oop(p)->size()) {
1463 _mark_bitmap.mark_obj(p, words);
1464 _summary_data.add_obj(p, words);
1465 start_array->allocate_block(p);
1466 }
1467 }
1468
1469 void
1470 PSParallelCompact::summarize_new_objects(SpaceId id, HeapWord* start)
1471 {
1472 ParallelCompactData& sd = summary_data();
1473 MutableSpace* space = _space_info[id].space();
1474
1475 // Find the source and destination start addresses.
1476 HeapWord* const src_addr = sd.region_align_down(start);
1477 HeapWord* dst_addr;
1478 if (src_addr < start) {
1479 dst_addr = sd.addr_to_region_ptr(src_addr)->destination();
1480 } else if (src_addr > space->bottom()) {
1481 // The start (the original top() value) is aligned to a region boundary so
1482 // the associated region does not have a destination. Compute the
1483 // destination from the previous region.
1484 RegionData* const cp = sd.addr_to_region_ptr(src_addr) - 1;
1485 dst_addr = cp->destination() + cp->data_size();
1486 } else {
1487 // Filling the entire space.
1488 dst_addr = space->bottom();
1489 }
1490 assert(dst_addr != NULL, "sanity");
1491
1492 // Update the summary data.
1493 bool result = _summary_data.summarize(_space_info[id].split_info(),
1494 src_addr, space->top(), NULL,
1495 dst_addr, space->end(),
1496 _space_info[id].new_top_addr());
1497 assert(result, "should not fail: bad filler object size");
1498 }
1499
1500 void
1501 PSParallelCompact::provoke_split_fill_survivor(SpaceId id)
1502 {
1503 if (total_invocations() % (ParallelOldGCSplitInterval * 3) != 0) {
1504 return;
1505 }
1506
1507 MutableSpace* const space = _space_info[id].space();
1508 if (space->is_empty()) {
1509 HeapWord* b = space->bottom();
1510 HeapWord* t = b + space->capacity_in_words() / 2;
1511 space->set_top(t);
1512 if (ZapUnusedHeapArea) {
1513 space->set_top_for_allocations();
1514 }
1515
1516 size_t min_size = CollectedHeap::min_fill_size();
1517 size_t obj_len = min_size;
1518 while (b + obj_len <= t) {
1519 CollectedHeap::fill_with_object(b, obj_len);
1520 mark_bitmap()->mark_obj(b, obj_len);
1521 summary_data().add_obj(b, obj_len);
1522 b += obj_len;
1523 obj_len = (obj_len & (min_size*3)) + min_size; // 8 16 24 32 8 16 24 32 ...
1524 }
1525 if (b < t) {
1526 // The loop didn't completely fill to t (top); adjust top downward.
1527 space->set_top(b);
1528 if (ZapUnusedHeapArea) {
1529 space->set_top_for_allocations();
1530 }
1531 }
1532
1533 HeapWord** nta = _space_info[id].new_top_addr();
1534 bool result = summary_data().summarize(_space_info[id].split_info(),
1535 space->bottom(), space->top(), NULL,
1536 space->bottom(), space->end(), nta);
1537 assert(result, "space must fit into itself");
1538 }
1539 }
1540
1541 void
1542 PSParallelCompact::provoke_split(bool & max_compaction)
1543 {
1544 if (total_invocations() % ParallelOldGCSplitInterval != 0) {
1545 return;
1546 }
1547
1548 const size_t region_size = ParallelCompactData::RegionSize;
1549 ParallelCompactData& sd = summary_data();
1550
1551 MutableSpace* const eden_space = _space_info[eden_space_id].space();
1552 MutableSpace* const from_space = _space_info[from_space_id].space();
1553 const size_t eden_live = pointer_delta(eden_space->top(),
1554 _space_info[eden_space_id].new_top());
1555 const size_t from_live = pointer_delta(from_space->top(),
1556 _space_info[from_space_id].new_top());
1557
1558 const size_t min_fill_size = CollectedHeap::min_fill_size();
1559 const size_t eden_free = pointer_delta(eden_space->end(), eden_space->top());
1560 const size_t eden_fillable = eden_free >= min_fill_size ? eden_free : 0;
1561 const size_t from_free = pointer_delta(from_space->end(), from_space->top());
1562 const size_t from_fillable = from_free >= min_fill_size ? from_free : 0;
1563
1564 // Choose the space to split; need at least 2 regions live (or fillable).
1565 SpaceId id;
1566 MutableSpace* space;
1567 size_t live_words;
1568 size_t fill_words;
1569 if (eden_live + eden_fillable >= region_size * 2) {
1570 id = eden_space_id;
1571 space = eden_space;
1572 live_words = eden_live;
1573 fill_words = eden_fillable;
1574 } else if (from_live + from_fillable >= region_size * 2) {
1575 id = from_space_id;
1576 space = from_space;
1577 live_words = from_live;
1578 fill_words = from_fillable;
1579 } else {
1580 return; // Give up.
1581 }
1582 assert(fill_words == 0 || fill_words >= min_fill_size, "sanity");
1583
1584 if (live_words < region_size * 2) {
1585 // Fill from top() to end() w/live objects of mixed sizes.
1586 HeapWord* const fill_start = space->top();
1587 live_words += fill_words;
1588
1589 space->set_top(fill_start + fill_words);
1590 if (ZapUnusedHeapArea) {
1591 space->set_top_for_allocations();
1592 }
1593
1594 HeapWord* cur_addr = fill_start;
1595 while (fill_words > 0) {
1596 const size_t r = (size_t)os::random() % (region_size / 2) + min_fill_size;
1597 size_t cur_size = MIN2(align_object_size_(r), fill_words);
1598 if (fill_words - cur_size < min_fill_size) {
1599 cur_size = fill_words; // Avoid leaving a fragment too small to fill.
1600 }
1601
1602 CollectedHeap::fill_with_object(cur_addr, cur_size);
1603 mark_bitmap()->mark_obj(cur_addr, cur_size);
1604 sd.add_obj(cur_addr, cur_size);
1605
1606 cur_addr += cur_size;
1607 fill_words -= cur_size;
1608 }
1609
1610 summarize_new_objects(id, fill_start);
1611 }
1612
1613 max_compaction = false;
1614
1615 // Manipulate the old gen so that it has room for about half of the live data
1616 // in the target young gen space (live_words / 2).
1617 id = old_space_id;
1618 space = _space_info[id].space();
1619 const size_t free_at_end = space->free_in_words();
1620 const size_t free_target = align_object_size(live_words / 2);
1621 const size_t dead = pointer_delta(space->top(), _space_info[id].new_top());
1622
1623 if (free_at_end >= free_target + min_fill_size) {
1624 // Fill space above top() and set the dense prefix so everything survives.
1625 HeapWord* const fill_start = space->top();
1626 const size_t fill_size = free_at_end - free_target;
1627 space->set_top(space->top() + fill_size);
1628 if (ZapUnusedHeapArea) {
1629 space->set_top_for_allocations();
1630 }
1631 fill_with_live_objects(id, fill_start, fill_size);
1632 summarize_new_objects(id, fill_start);
1633 _space_info[id].set_dense_prefix(sd.region_align_down(space->top()));
1634 } else if (dead + free_at_end > free_target) {
1635 // Find a dense prefix that makes the right amount of space available.
1636 HeapWord* cur = sd.region_align_down(space->top());
1637 HeapWord* cur_destination = sd.addr_to_region_ptr(cur)->destination();
1638 size_t dead_to_right = pointer_delta(space->end(), cur_destination);
1639 while (dead_to_right < free_target) {
1640 cur -= region_size;
1641 cur_destination = sd.addr_to_region_ptr(cur)->destination();
1642 dead_to_right = pointer_delta(space->end(), cur_destination);
1643 }
1644 _space_info[id].set_dense_prefix(cur);
1645 }
1646 }
1647 #endif // #ifndef PRODUCT
1648
1649 void PSParallelCompact::summarize_spaces_quick()
1650 {
1651 for (unsigned int i = 0; i < last_space_id; ++i) {
1652 const MutableSpace* space = _space_info[i].space();
1653 HeapWord** nta = _space_info[i].new_top_addr();
1654 bool result = _summary_data.summarize(_space_info[i].split_info(),
1655 space->bottom(), space->top(), NULL,
1656 space->bottom(), space->end(), nta);
1657 assert(result, "space must fit into itself");
1658 _space_info[i].set_dense_prefix(space->bottom());
1659 }
1660
1661 #ifndef PRODUCT
1662 if (ParallelOldGCSplitALot) {
1663 provoke_split_fill_survivor(to_space_id);
1664 }
1665 #endif // #ifndef PRODUCT
1666 }
1667
1668 void PSParallelCompact::fill_dense_prefix_end(SpaceId id)
1669 {
1670 HeapWord* const dense_prefix_end = dense_prefix(id);
1671 const RegionData* region = _summary_data.addr_to_region_ptr(dense_prefix_end);
1672 const idx_t dense_prefix_bit = _mark_bitmap.addr_to_bit(dense_prefix_end);
1673 if (dead_space_crosses_boundary(region, dense_prefix_bit)) {
1674 // Only enough dead space is filled so that any remaining dead space to the
1675 // left is larger than the minimum filler object. (The remainder is filled
1676 // during the copy/update phase.)
1677 //
1678 // The size of the dead space to the right of the boundary is not a
1679 // concern, since compaction will be able to use whatever space is
1680 // available.
1681 //
1682 // Here '||' is the boundary, 'x' represents a don't care bit and a box
1683 // surrounds the space to be filled with an object.
1684 //
1685 // In the 32-bit VM, each bit represents two 32-bit words:
1686 // +---+
1687 // a) beg_bits: ... x x x | 0 | || 0 x x ...
1688 // end_bits: ... x x x | 0 | || 0 x x ...
1689 // +---+
1690 //
1691 // In the 64-bit VM, each bit represents one 64-bit word:
1692 // +------------+
1693 // b) beg_bits: ... x x x | 0 || 0 | x x ...
1694 // end_bits: ... x x 1 | 0 || 0 | x x ...
1695 // +------------+
1696 // +-------+
1697 // c) beg_bits: ... x x | 0 0 | || 0 x x ...
1698 // end_bits: ... x 1 | 0 0 | || 0 x x ...
1699 // +-------+
1700 // +-----------+
1701 // d) beg_bits: ... x | 0 0 0 | || 0 x x ...
1702 // end_bits: ... 1 | 0 0 0 | || 0 x x ...
1703 // +-----------+
1704 // +-------+
1705 // e) beg_bits: ... 0 0 | 0 0 | || 0 x x ...
1706 // end_bits: ... 0 0 | 0 0 | || 0 x x ...
1707 // +-------+
1708
1709 // Initially assume case a, c or e will apply.
1710 size_t obj_len = CollectedHeap::min_fill_size();
1711 HeapWord* obj_beg = dense_prefix_end - obj_len;
1712
1713 #ifdef _LP64
1714 if (MinObjAlignment > 1) { // object alignment > heap word size
1715 // Cases a, c or e.
1716 } else if (_mark_bitmap.is_obj_end(dense_prefix_bit - 2)) {
1717 // Case b above.
1718 obj_beg = dense_prefix_end - 1;
1719 } else if (!_mark_bitmap.is_obj_end(dense_prefix_bit - 3) &&
1720 _mark_bitmap.is_obj_end(dense_prefix_bit - 4)) {
1721 // Case d above.
1722 obj_beg = dense_prefix_end - 3;
1723 obj_len = 3;
1724 }
1725 #endif // #ifdef _LP64
1726
1727 CollectedHeap::fill_with_object(obj_beg, obj_len);
1728 _mark_bitmap.mark_obj(obj_beg, obj_len);
1729 _summary_data.add_obj(obj_beg, obj_len);
1730 assert(start_array(id) != NULL, "sanity");
1731 start_array(id)->allocate_block(obj_beg);
1732 }
1733 }
1734
1735 void
1736 PSParallelCompact::clear_source_region(HeapWord* beg_addr, HeapWord* end_addr)
1737 {
1738 RegionData* const beg_ptr = _summary_data.addr_to_region_ptr(beg_addr);
1739 HeapWord* const end_aligned_up = _summary_data.region_align_up(end_addr);
1740 RegionData* const end_ptr = _summary_data.addr_to_region_ptr(end_aligned_up);
1741 for (RegionData* cur = beg_ptr; cur < end_ptr; ++cur) {
1742 cur->set_source_region(0);
1743 }
1744 }
1745
1746 void
1747 PSParallelCompact::summarize_space(SpaceId id, bool maximum_compaction)
1748 {
1749 assert(id < last_space_id, "id out of range");
1750 assert(_space_info[id].dense_prefix() == _space_info[id].space()->bottom() ||
1751 ParallelOldGCSplitALot && id == old_space_id,
1752 "should have been reset in summarize_spaces_quick()");
1753
1754 const MutableSpace* space = _space_info[id].space();
1755 if (_space_info[id].new_top() != space->bottom()) {
1756 HeapWord* dense_prefix_end = compute_dense_prefix(id, maximum_compaction);
1757 _space_info[id].set_dense_prefix(dense_prefix_end);
1758
1759 #ifndef PRODUCT
1760 if (TraceParallelOldGCDensePrefix) {
1761 print_dense_prefix_stats("ratio", id, maximum_compaction,
1762 dense_prefix_end);
1763 HeapWord* addr = compute_dense_prefix_via_density(id, maximum_compaction);
1764 print_dense_prefix_stats("density", id, maximum_compaction, addr);
1765 }
1766 #endif // #ifndef PRODUCT
1767
1768 // Recompute the summary data, taking into account the dense prefix. If
1769 // every last byte will be reclaimed, then the existing summary data which
1770 // compacts everything can be left in place.
1771 if (!maximum_compaction && dense_prefix_end != space->bottom()) {
1772 // If dead space crosses the dense prefix boundary, it is (at least
1773 // partially) filled with a dummy object, marked live and added to the
1774 // summary data. This simplifies the copy/update phase and must be done
1775 // before the final locations of objects are determined, to prevent
1776 // leaving a fragment of dead space that is too small to fill.
1777 fill_dense_prefix_end(id);
1778
1779 // Compute the destination of each Region, and thus each object.
1780 _summary_data.summarize_dense_prefix(space->bottom(), dense_prefix_end);
1781 _summary_data.summarize(_space_info[id].split_info(),
1782 dense_prefix_end, space->top(), NULL,
1783 dense_prefix_end, space->end(),
1784 _space_info[id].new_top_addr());
1785 }
1786 }
1787
1788 if (TraceParallelOldGCSummaryPhase) {
1789 const size_t region_size = ParallelCompactData::RegionSize;
1790 HeapWord* const dense_prefix_end = _space_info[id].dense_prefix();
1791 const size_t dp_region = _summary_data.addr_to_region_idx(dense_prefix_end);
1792 const size_t dp_words = pointer_delta(dense_prefix_end, space->bottom());
1793 HeapWord* const new_top = _space_info[id].new_top();
1794 const HeapWord* nt_aligned_up = _summary_data.region_align_up(new_top);
1795 const size_t cr_words = pointer_delta(nt_aligned_up, dense_prefix_end);
1796 tty->print_cr("id=%d cap=" SIZE_FORMAT " dp=" PTR_FORMAT " "
1797 "dp_region=" SIZE_FORMAT " " "dp_count=" SIZE_FORMAT " "
1798 "cr_count=" SIZE_FORMAT " " "nt=" PTR_FORMAT,
1799 id, space->capacity_in_words(), p2i(dense_prefix_end),
1800 dp_region, dp_words / region_size,
1801 cr_words / region_size, p2i(new_top));
1802 }
1803 }
1804
1805 #ifndef PRODUCT
1806 void PSParallelCompact::summary_phase_msg(SpaceId dst_space_id,
1807 HeapWord* dst_beg, HeapWord* dst_end,
1808 SpaceId src_space_id,
1809 HeapWord* src_beg, HeapWord* src_end)
1810 {
1811 if (TraceParallelOldGCSummaryPhase) {
1812 tty->print_cr("summarizing %d [%s] into %d [%s]: "
1813 "src=" PTR_FORMAT "-" PTR_FORMAT " "
1814 SIZE_FORMAT "-" SIZE_FORMAT " "
1815 "dst=" PTR_FORMAT "-" PTR_FORMAT " "
1816 SIZE_FORMAT "-" SIZE_FORMAT,
1817 src_space_id, space_names[src_space_id],
1818 dst_space_id, space_names[dst_space_id],
1819 p2i(src_beg), p2i(src_end),
1820 _summary_data.addr_to_region_idx(src_beg),
1821 _summary_data.addr_to_region_idx(src_end),
1822 p2i(dst_beg), p2i(dst_end),
1823 _summary_data.addr_to_region_idx(dst_beg),
1824 _summary_data.addr_to_region_idx(dst_end));
1825 }
1826 }
1827 #endif // #ifndef PRODUCT
1828
1829 void PSParallelCompact::summary_phase(ParCompactionManager* cm,
1830 bool maximum_compaction)
1831 {
1832 GCTraceTime tm("summary phase", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
1833 // trace("2");
1834
1835 #ifdef ASSERT
1836 if (TraceParallelOldGCMarkingPhase) {
1837 tty->print_cr("add_obj_count=" SIZE_FORMAT " "
1838 "add_obj_bytes=" SIZE_FORMAT,
1839 add_obj_count, add_obj_size * HeapWordSize);
1840 tty->print_cr("mark_bitmap_count=" SIZE_FORMAT " "
1841 "mark_bitmap_bytes=" SIZE_FORMAT,
1842 mark_bitmap_count, mark_bitmap_size * HeapWordSize);
1843 }
1844 #endif // #ifdef ASSERT
1845
1846 // Quick summarization of each space into itself, to see how much is live.
1847 summarize_spaces_quick();
1848
1849 if (TraceParallelOldGCSummaryPhase) {
1850 tty->print_cr("summary_phase: after summarizing each space to self");
1851 Universe::print();
1852 NOT_PRODUCT(print_region_ranges());
1853 if (Verbose) {
1854 NOT_PRODUCT(print_initial_summary_data(_summary_data, _space_info));
1855 }
1856 }
1857
1858 // The amount of live data that will end up in old space (assuming it fits).
1859 size_t old_space_total_live = 0;
1860 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
1861 old_space_total_live += pointer_delta(_space_info[id].new_top(),
1862 _space_info[id].space()->bottom());
1863 }
1864
1865 MutableSpace* const old_space = _space_info[old_space_id].space();
1866 const size_t old_capacity = old_space->capacity_in_words();
1867 if (old_space_total_live > old_capacity) {
1868 // XXX - should also try to expand
1869 maximum_compaction = true;
1870 }
1871 #ifndef PRODUCT
1872 if (ParallelOldGCSplitALot && old_space_total_live < old_capacity) {
1873 provoke_split(maximum_compaction);
1874 }
1875 #endif // #ifndef PRODUCT
1876
1877 // Old generations.
1878 summarize_space(old_space_id, maximum_compaction);
1879
1880 // Summarize the remaining spaces in the young gen. The initial target space
1881 // is the old gen. If a space does not fit entirely into the target, then the
1882 // remainder is compacted into the space itself and that space becomes the new
1883 // target.
1884 SpaceId dst_space_id = old_space_id;
1885 HeapWord* dst_space_end = old_space->end();
1886 HeapWord** new_top_addr = _space_info[dst_space_id].new_top_addr();
1887 for (unsigned int id = eden_space_id; id < last_space_id; ++id) {
1888 const MutableSpace* space = _space_info[id].space();
1889 const size_t live = pointer_delta(_space_info[id].new_top(),
1890 space->bottom());
1891 const size_t available = pointer_delta(dst_space_end, *new_top_addr);
1892
1893 NOT_PRODUCT(summary_phase_msg(dst_space_id, *new_top_addr, dst_space_end,
1894 SpaceId(id), space->bottom(), space->top());)
1895 if (live > 0 && live <= available) {
1896 // All the live data will fit.
1897 bool done = _summary_data.summarize(_space_info[id].split_info(),
1898 space->bottom(), space->top(),
1899 NULL,
1900 *new_top_addr, dst_space_end,
1901 new_top_addr);
1902 assert(done, "space must fit into old gen");
1903
1904 // Reset the new_top value for the space.
1905 _space_info[id].set_new_top(space->bottom());
1906 } else if (live > 0) {
1907 // Attempt to fit part of the source space into the target space.
1908 HeapWord* next_src_addr = NULL;
1909 bool done = _summary_data.summarize(_space_info[id].split_info(),
1910 space->bottom(), space->top(),
1911 &next_src_addr,
1912 *new_top_addr, dst_space_end,
1913 new_top_addr);
1914 assert(!done, "space should not fit into old gen");
1915 assert(next_src_addr != NULL, "sanity");
1916
1917 // The source space becomes the new target, so the remainder is compacted
1918 // within the space itself.
1919 dst_space_id = SpaceId(id);
1920 dst_space_end = space->end();
1921 new_top_addr = _space_info[id].new_top_addr();
1922 NOT_PRODUCT(summary_phase_msg(dst_space_id,
1923 space->bottom(), dst_space_end,
1924 SpaceId(id), next_src_addr, space->top());)
1925 done = _summary_data.summarize(_space_info[id].split_info(),
1926 next_src_addr, space->top(),
1927 NULL,
1928 space->bottom(), dst_space_end,
1929 new_top_addr);
1930 assert(done, "space must fit when compacted into itself");
1931 assert(*new_top_addr <= space->top(), "usage should not grow");
1932 }
1933 }
1934
1935 if (TraceParallelOldGCSummaryPhase) {
1936 tty->print_cr("summary_phase: after final summarization");
1937 Universe::print();
1938 NOT_PRODUCT(print_region_ranges());
1939 if (Verbose) {
1940 NOT_PRODUCT(print_generic_summary_data(_summary_data, _space_info));
1941 }
1942 }
1943 }
1944
1945 // This method should contain all heap-specific policy for invoking a full
1946 // collection. invoke_no_policy() will only attempt to compact the heap; it
1947 // will do nothing further. If we need to bail out for policy reasons, scavenge
1948 // before full gc, or any other specialized behavior, it needs to be added here.
1949 //
1950 // Note that this method should only be called from the vm_thread while at a
1951 // safepoint.
1952 //
1953 // Note that the all_soft_refs_clear flag in the collector policy
1954 // may be true because this method can be called without intervening
1955 // activity. For example when the heap space is tight and full measure
1956 // are being taken to free space.
1957 void PSParallelCompact::invoke(bool maximum_heap_compaction) {
1958 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
1959 assert(Thread::current() == (Thread*)VMThread::vm_thread(),
1960 "should be in vm thread");
1961
1962 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
1963 GCCause::Cause gc_cause = heap->gc_cause();
1964 assert(!heap->is_gc_active(), "not reentrant");
1965
1966 PSAdaptiveSizePolicy* policy = heap->size_policy();
1967 IsGCActiveMark mark;
1968
1969 if (ScavengeBeforeFullGC) {
1970 PSScavenge::invoke_no_policy();
1971 }
1972
1973 const bool clear_all_soft_refs =
1974 heap->collector_policy()->should_clear_all_soft_refs();
1975
1976 PSParallelCompact::invoke_no_policy(clear_all_soft_refs ||
1977 maximum_heap_compaction);
1978 }
1979
1980 // This method contains no policy. You should probably
1981 // be calling invoke() instead.
1982 bool PSParallelCompact::invoke_no_policy(bool maximum_heap_compaction) {
1983 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
1984 assert(ref_processor() != NULL, "Sanity");
1985
1986 if (GC_locker::check_active_before_gc()) {
1987 return false;
1988 }
1989
1990 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
1991
1992 _gc_timer.register_gc_start();
1993 _gc_tracer.report_gc_start(heap->gc_cause(), _gc_timer.gc_start());
1994
1995 TimeStamp marking_start;
1996 TimeStamp compaction_start;
1997 TimeStamp collection_exit;
1998
1999 GCCause::Cause gc_cause = heap->gc_cause();
2000 PSYoungGen* young_gen = heap->young_gen();
2001 PSOldGen* old_gen = heap->old_gen();
2002 PSAdaptiveSizePolicy* size_policy = heap->size_policy();
2003
2004 // The scope of casr should end after code that can change
2005 // CollectorPolicy::_should_clear_all_soft_refs.
2006 ClearedAllSoftRefs casr(maximum_heap_compaction,
2007 heap->collector_policy());
2008
2009 if (ZapUnusedHeapArea) {
2010 // Save information needed to minimize mangling
2011 heap->record_gen_tops_before_GC();
2012 }
2013
2014 heap->pre_full_gc_dump(&_gc_timer);
2015
2016 _print_phases = PrintGCDetails && PrintParallelOldGCPhaseTimes;
2017
2018 // Make sure data structures are sane, make the heap parsable, and do other
2019 // miscellaneous bookkeeping.
2020 PreGCValues pre_gc_values;
2021 pre_compact(&pre_gc_values);
2022
2023 // Get the compaction manager reserved for the VM thread.
2024 ParCompactionManager* const vmthread_cm =
2025 ParCompactionManager::manager_array(gc_task_manager()->workers());
2026
2027 // Place after pre_compact() where the number of invocations is incremented.
2028 AdaptiveSizePolicyOutput(size_policy, heap->total_collections());
2029
2030 {
2031 ResourceMark rm;
2032 HandleMark hm;
2033
2034 // Set the number of GC threads to be used in this collection
2035 gc_task_manager()->set_active_gang();
2036 gc_task_manager()->task_idle_workers();
2037 heap->set_par_threads(gc_task_manager()->active_workers());
2038
2039 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
2040 GCTraceTime t1(GCCauseString("Full GC", gc_cause), PrintGC, !PrintGCDetails, NULL, _gc_tracer.gc_id());
2041 TraceCollectorStats tcs(counters());
2042 TraceMemoryManagerStats tms(true /* Full GC */,gc_cause);
2043
2044 if (TraceOldGenTime) accumulated_time()->start();
2045
2046 // Let the size policy know we're starting
2047 size_policy->major_collection_begin();
2048
2049 CodeCache::gc_prologue();
2050
2051 COMPILER2_PRESENT(DerivedPointerTable::clear());
2052
2053 ref_processor()->enable_discovery();
2054 ref_processor()->setup_policy(maximum_heap_compaction);
2055
2056 bool marked_for_unloading = false;
2057
2058 marking_start.update();
2059 marking_phase(vmthread_cm, maximum_heap_compaction, &_gc_tracer);
2060
2061 bool max_on_system_gc = UseMaximumCompactionOnSystemGC
2062 && gc_cause == GCCause::_java_lang_system_gc;
2063 summary_phase(vmthread_cm, maximum_heap_compaction || max_on_system_gc);
2064
2065 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity"));
2066 COMPILER2_PRESENT(DerivedPointerTable::set_active(false));
2067
2068 // adjust_roots() updates Universe::_intArrayKlassObj which is
2069 // needed by the compaction for filling holes in the dense prefix.
2070 adjust_roots();
2071
2072 compaction_start.update();
2073 compact();
2074
2075 // Reset the mark bitmap, summary data, and do other bookkeeping. Must be
2076 // done before resizing.
2077 post_compact();
2078
2079 // Let the size policy know we're done
2080 size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause);
2081
2082 if (UseAdaptiveSizePolicy) {
2083 if (PrintAdaptiveSizePolicy) {
2084 gclog_or_tty->print("AdaptiveSizeStart: ");
2085 gclog_or_tty->stamp();
2086 gclog_or_tty->print_cr(" collection: %d ",
2087 heap->total_collections());
2088 if (Verbose) {
2089 gclog_or_tty->print("old_gen_capacity: " SIZE_FORMAT
2090 " young_gen_capacity: " SIZE_FORMAT,
2091 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes());
2092 }
2093 }
2094
2095 // Don't check if the size_policy is ready here. Let
2096 // the size_policy check that internally.
2097 if (UseAdaptiveGenerationSizePolicyAtMajorCollection &&
2098 ((gc_cause != GCCause::_java_lang_system_gc) ||
2099 UseAdaptiveSizePolicyWithSystemGC)) {
2100 // Swap the survivor spaces if from_space is empty. The
2101 // resize_young_gen() called below is normally used after
2102 // a successful young GC and swapping of survivor spaces;
2103 // otherwise, it will fail to resize the young gen with
2104 // the current implementation.
2105 if (young_gen->from_space()->is_empty()) {
2106 young_gen->from_space()->clear(SpaceDecorator::Mangle);
2107 young_gen->swap_spaces();
2108 }
2109
2110 // Calculate optimal free space amounts
2111 assert(young_gen->max_size() >
2112 young_gen->from_space()->capacity_in_bytes() +
2113 young_gen->to_space()->capacity_in_bytes(),
2114 "Sizes of space in young gen are out-of-bounds");
2115
2116 size_t young_live = young_gen->used_in_bytes();
2117 size_t eden_live = young_gen->eden_space()->used_in_bytes();
2118 size_t old_live = old_gen->used_in_bytes();
2119 size_t cur_eden = young_gen->eden_space()->capacity_in_bytes();
2120 size_t max_old_gen_size = old_gen->max_gen_size();
2121 size_t max_eden_size = young_gen->max_size() -
2122 young_gen->from_space()->capacity_in_bytes() -
2123 young_gen->to_space()->capacity_in_bytes();
2124
2125 // Used for diagnostics
2126 size_policy->clear_generation_free_space_flags();
2127
2128 size_policy->compute_generations_free_space(young_live,
2129 eden_live,
2130 old_live,
2131 cur_eden,
2132 max_old_gen_size,
2133 max_eden_size,
2134 true /* full gc*/);
2135
2136 size_policy->check_gc_overhead_limit(young_live,
2137 eden_live,
2138 max_old_gen_size,
2139 max_eden_size,
2140 true /* full gc*/,
2141 gc_cause,
2142 heap->collector_policy());
2143
2144 size_policy->decay_supplemental_growth(true /* full gc*/);
2145
2146 heap->resize_old_gen(
2147 size_policy->calculated_old_free_size_in_bytes());
2148
2149 heap->resize_young_gen(size_policy->calculated_eden_size_in_bytes(),
2150 size_policy->calculated_survivor_size_in_bytes());
2151 }
2152 if (PrintAdaptiveSizePolicy) {
2153 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ",
2154 heap->total_collections());
2155 }
2156 }
2157
2158 if (UsePerfData) {
2159 PSGCAdaptivePolicyCounters* const counters = heap->gc_policy_counters();
2160 counters->update_counters();
2161 counters->update_old_capacity(old_gen->capacity_in_bytes());
2162 counters->update_young_capacity(young_gen->capacity_in_bytes());
2163 }
2164
2165 heap->resize_all_tlabs();
2166
2167 // Resize the metaspace capacity after a collection
2168 MetaspaceGC::compute_new_size();
2169
2170 if (TraceOldGenTime) accumulated_time()->stop();
2171
2172 if (PrintGC) {
2173 if (PrintGCDetails) {
2174 // No GC timestamp here. This is after GC so it would be confusing.
2175 young_gen->print_used_change(pre_gc_values.young_gen_used());
2176 old_gen->print_used_change(pre_gc_values.old_gen_used());
2177 heap->print_heap_change(pre_gc_values.heap_used());
2178 MetaspaceAux::print_metaspace_change(pre_gc_values.metadata_used());
2179 } else {
2180 heap->print_heap_change(pre_gc_values.heap_used());
2181 }
2182 }
2183
2184 // Track memory usage and detect low memory
2185 MemoryService::track_memory_usage();
2186 heap->update_counters();
2187 gc_task_manager()->release_idle_workers();
2188 }
2189
2190 #ifdef ASSERT
2191 for (size_t i = 0; i < ParallelGCThreads + 1; ++i) {
2192 ParCompactionManager* const cm =
2193 ParCompactionManager::manager_array(int(i));
2194 assert(cm->marking_stack()->is_empty(), "should be empty");
2195 assert(ParCompactionManager::region_list(int(i))->is_empty(), "should be empty");
2196 }
2197 #endif // ASSERT
2198
2199 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
2200 HandleMark hm; // Discard invalid handles created during verification
2201 Universe::verify(" VerifyAfterGC:");
2202 }
2203
2204 // Re-verify object start arrays
2205 if (VerifyObjectStartArray &&
2206 VerifyAfterGC) {
2207 old_gen->verify_object_start_array();
2208 }
2209
2210 if (ZapUnusedHeapArea) {
2211 old_gen->object_space()->check_mangled_unused_area_complete();
2212 }
2213
2214 NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
2215
2216 collection_exit.update();
2217
2218 heap->print_heap_after_gc();
2219 heap->trace_heap_after_gc(&_gc_tracer);
2220
2221 if (PrintGCTaskTimeStamps) {
2222 gclog_or_tty->print_cr("VM-Thread " JLONG_FORMAT " " JLONG_FORMAT " "
2223 JLONG_FORMAT,
2224 marking_start.ticks(), compaction_start.ticks(),
2225 collection_exit.ticks());
2226 gc_task_manager()->print_task_time_stamps();
2227 }
2228
2229 heap->post_full_gc_dump(&_gc_timer);
2230
2231 #ifdef TRACESPINNING
2232 ParallelTaskTerminator::print_termination_counts();
2233 #endif
2234
2235 _gc_timer.register_gc_end();
2236
2237 _gc_tracer.report_dense_prefix(dense_prefix(old_space_id));
2238 _gc_tracer.report_gc_end(_gc_timer.gc_end(), _gc_timer.time_partitions());
2239
2240 return true;
2241 }
2242
2243 bool PSParallelCompact::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
2244 PSYoungGen* young_gen,
2245 PSOldGen* old_gen) {
2246 MutableSpace* const eden_space = young_gen->eden_space();
2247 assert(!eden_space->is_empty(), "eden must be non-empty");
2248 assert(young_gen->virtual_space()->alignment() ==
2249 old_gen->virtual_space()->alignment(), "alignments do not match");
2250
2251 if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) {
2252 return false;
2253 }
2254
2255 // Both generations must be completely committed.
2256 if (young_gen->virtual_space()->uncommitted_size() != 0) {
2257 return false;
2258 }
2259 if (old_gen->virtual_space()->uncommitted_size() != 0) {
2260 return false;
2261 }
2262
2263 // Figure out how much to take from eden. Include the average amount promoted
2264 // in the total; otherwise the next young gen GC will simply bail out to a
2265 // full GC.
2266 const size_t alignment = old_gen->virtual_space()->alignment();
2267 const size_t eden_used = eden_space->used_in_bytes();
2268 const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average();
2269 const size_t absorb_size = align_size_up(eden_used + promoted, alignment);
2270 const size_t eden_capacity = eden_space->capacity_in_bytes();
2271
2272 if (absorb_size >= eden_capacity) {
2273 return false; // Must leave some space in eden.
2274 }
2275
2276 const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size;
2277 if (new_young_size < young_gen->min_gen_size()) {
2278 return false; // Respect young gen minimum size.
2279 }
2280
2281 if (TraceAdaptiveGCBoundary && Verbose) {
2282 gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: "
2283 "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K "
2284 "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K "
2285 "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ",
2286 absorb_size / K,
2287 eden_capacity / K, (eden_capacity - absorb_size) / K,
2288 young_gen->from_space()->used_in_bytes() / K,
2289 young_gen->to_space()->used_in_bytes() / K,
2290 young_gen->capacity_in_bytes() / K, new_young_size / K);
2291 }
2292
2293 // Fill the unused part of the old gen.
2294 MutableSpace* const old_space = old_gen->object_space();
2295 HeapWord* const unused_start = old_space->top();
2296 size_t const unused_words = pointer_delta(old_space->end(), unused_start);
2297
2298 if (unused_words > 0) {
2299 if (unused_words < CollectedHeap::min_fill_size()) {
2300 return false; // If the old gen cannot be filled, must give up.
2301 }
2302 CollectedHeap::fill_with_objects(unused_start, unused_words);
2303 }
2304
2305 // Take the live data from eden and set both top and end in the old gen to
2306 // eden top. (Need to set end because reset_after_change() mangles the region
2307 // from end to virtual_space->high() in debug builds).
2308 HeapWord* const new_top = eden_space->top();
2309 old_gen->virtual_space()->expand_into(young_gen->virtual_space(),
2310 absorb_size);
2311 young_gen->reset_after_change();
2312 old_space->set_top(new_top);
2313 old_space->set_end(new_top);
2314 old_gen->reset_after_change();
2315
2316 // Update the object start array for the filler object and the data from eden.
2317 ObjectStartArray* const start_array = old_gen->start_array();
2318 for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) {
2319 start_array->allocate_block(p);
2320 }
2321
2322 // Could update the promoted average here, but it is not typically updated at
2323 // full GCs and the value to use is unclear. Something like
2324 //
2325 // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc.
2326
2327 size_policy->set_bytes_absorbed_from_eden(absorb_size);
2328 return true;
2329 }
2330
2331 GCTaskManager* const PSParallelCompact::gc_task_manager() {
2332 assert(ParallelScavengeHeap::gc_task_manager() != NULL,
2333 "shouldn't return NULL");
2334 return ParallelScavengeHeap::gc_task_manager();
2335 }
2336
2337 void PSParallelCompact::marking_phase(ParCompactionManager* cm,
2338 bool maximum_heap_compaction,
2339 ParallelOldTracer *gc_tracer) {
2340 // Recursively traverse all live objects and mark them
2341 GCTraceTime tm("marking phase", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2342
2343 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
2344 uint parallel_gc_threads = heap->gc_task_manager()->workers();
2345 uint active_gc_threads = heap->gc_task_manager()->active_workers();
2346 TaskQueueSetSuper* qset = ParCompactionManager::region_array();
2347 ParallelTaskTerminator terminator(active_gc_threads, qset);
2348
2349 PSParallelCompact::MarkAndPushClosure mark_and_push_closure(cm);
2350 PSParallelCompact::FollowStackClosure follow_stack_closure(cm);
2351
2352 // Need new claim bits before marking starts.
2353 ClassLoaderDataGraph::clear_claimed_marks();
2354
2355 {
2356 GCTraceTime tm_m("par mark", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2357
2358 ParallelScavengeHeap::ParStrongRootsScope psrs;
2359
2360 GCTaskQueue* q = GCTaskQueue::create();
2361
2362 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::universe));
2363 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::jni_handles));
2364 // We scan the thread roots in parallel
2365 Threads::create_thread_roots_marking_tasks(q);
2366 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::object_synchronizer));
2367 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::flat_profiler));
2368 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::management));
2369 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::system_dictionary));
2370 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::class_loader_data));
2371 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::jvmti));
2372 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::code_cache));
2373
2374 if (active_gc_threads > 1) {
2375 for (uint j = 0; j < active_gc_threads; j++) {
2376 q->enqueue(new StealMarkingTask(&terminator));
2377 }
2378 }
2379
2380 gc_task_manager()->execute_and_wait(q);
2381 }
2382
2383 // Process reference objects found during marking
2384 {
2385 GCTraceTime tm_r("reference processing", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2386
2387 ReferenceProcessorStats stats;
2388 if (ref_processor()->processing_is_mt()) {
2389 RefProcTaskExecutor task_executor;
2390 stats = ref_processor()->process_discovered_references(
2391 is_alive_closure(), &mark_and_push_closure, &follow_stack_closure,
2392 &task_executor, &_gc_timer, _gc_tracer.gc_id());
2393 } else {
2394 stats = ref_processor()->process_discovered_references(
2395 is_alive_closure(), &mark_and_push_closure, &follow_stack_closure, NULL,
2396 &_gc_timer, _gc_tracer.gc_id());
2397 }
2398
2399 gc_tracer->report_gc_reference_stats(stats);
2400 }
2401
2402 GCTraceTime tm_c("class unloading", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2403
2404 // This is the point where the entire marking should have completed.
2405 assert(cm->marking_stacks_empty(), "Marking should have completed");
2406
2407 // Follow system dictionary roots and unload classes.
2408 bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
2409
2410 // Unload nmethods.
2411 CodeCache::do_unloading(is_alive_closure(), purged_class);
2412
2413 // Prune dead klasses from subklass/sibling/implementor lists.
2414 Klass::clean_weak_klass_links(is_alive_closure());
2415
2416 // Delete entries for dead interned strings.
2417 StringTable::unlink(is_alive_closure());
2418
2419 // Clean up unreferenced symbols in symbol table.
2420 SymbolTable::unlink();
2421 _gc_tracer.report_object_count_after_gc(is_alive_closure());
2422 }
2423
2424 void PSParallelCompact::follow_class_loader(ParCompactionManager* cm,
2425 ClassLoaderData* cld) {
2426 PSParallelCompact::MarkAndPushClosure mark_and_push_closure(cm);
2427 PSParallelCompact::FollowKlassClosure follow_klass_closure(&mark_and_push_closure);
2428
2429 cld->oops_do(&mark_and_push_closure, &follow_klass_closure, true);
2430 }
2431
2432 // This should be moved to the shared markSweep code!
2433 class PSAlwaysTrueClosure: public BoolObjectClosure {
2434 public:
2435 bool do_object_b(oop p) { return true; }
2436 };
2437 static PSAlwaysTrueClosure always_true;
2438
2439 void PSParallelCompact::adjust_roots() {
2440 // Adjust the pointers to reflect the new locations
2441 GCTraceTime tm("adjust roots", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2442
2443 // Need new claim bits when tracing through and adjusting pointers.
2444 ClassLoaderDataGraph::clear_claimed_marks();
2445
2446 // General strong roots.
2447 Universe::oops_do(adjust_pointer_closure());
2448 JNIHandles::oops_do(adjust_pointer_closure()); // Global (strong) JNI handles
2449 CLDToOopClosure adjust_from_cld(adjust_pointer_closure());
2450 Threads::oops_do(adjust_pointer_closure(), &adjust_from_cld, NULL);
2451 ObjectSynchronizer::oops_do(adjust_pointer_closure());
2452 FlatProfiler::oops_do(adjust_pointer_closure());
2453 Management::oops_do(adjust_pointer_closure());
2454 JvmtiExport::oops_do(adjust_pointer_closure());
2455 SystemDictionary::oops_do(adjust_pointer_closure());
2456 ClassLoaderDataGraph::oops_do(adjust_pointer_closure(), adjust_klass_closure(), true);
2457
2458 // Now adjust pointers in remaining weak roots. (All of which should
2459 // have been cleared if they pointed to non-surviving objects.)
2460 // Global (weak) JNI handles
2461 JNIHandles::weak_oops_do(&always_true, adjust_pointer_closure());
2462
2463 CodeBlobToOopClosure adjust_from_blobs(adjust_pointer_closure(), CodeBlobToOopClosure::FixRelocations);
2464 CodeCache::blobs_do(&adjust_from_blobs);
2465 StringTable::oops_do(adjust_pointer_closure());
2466 ref_processor()->weak_oops_do(adjust_pointer_closure());
2467 // Roots were visited so references into the young gen in roots
2468 // may have been scanned. Process them also.
2469 // Should the reference processor have a span that excludes
2470 // young gen objects?
2471 PSScavenge::reference_processor()->weak_oops_do(adjust_pointer_closure());
2472 }
2473
2474 void PSParallelCompact::enqueue_region_draining_tasks(GCTaskQueue* q,
2475 uint parallel_gc_threads)
2476 {
2477 GCTraceTime tm("drain task setup", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2478
2479 // Find the threads that are active
2480 unsigned int which = 0;
2481
2482 const uint task_count = MAX2(parallel_gc_threads, 1U);
2483 for (uint j = 0; j < task_count; j++) {
2484 q->enqueue(new DrainStacksCompactionTask(j));
2485 ParCompactionManager::verify_region_list_empty(j);
2486 // Set the region stacks variables to "no" region stack values
2487 // so that they will be recognized and needing a region stack
2488 // in the stealing tasks if they do not get one by executing
2489 // a draining stack.
2490 ParCompactionManager* cm = ParCompactionManager::manager_array(j);
2491 cm->set_region_stack(NULL);
2492 cm->set_region_stack_index((uint)max_uintx);
2493 }
2494 ParCompactionManager::reset_recycled_stack_index();
2495
2496 // Find all regions that are available (can be filled immediately) and
2497 // distribute them to the thread stacks. The iteration is done in reverse
2498 // order (high to low) so the regions will be removed in ascending order.
2499
2500 const ParallelCompactData& sd = PSParallelCompact::summary_data();
2501
2502 size_t fillable_regions = 0; // A count for diagnostic purposes.
2503 // A region index which corresponds to the tasks created above.
2504 // "which" must be 0 <= which < task_count
2505
2506 which = 0;
2507 // id + 1 is used to test termination so unsigned can
2508 // be used with an old_space_id == 0.
2509 for (unsigned int id = to_space_id; id + 1 > old_space_id; --id) {
2510 SpaceInfo* const space_info = _space_info + id;
2511 MutableSpace* const space = space_info->space();
2512 HeapWord* const new_top = space_info->new_top();
2513
2514 const size_t beg_region = sd.addr_to_region_idx(space_info->dense_prefix());
2515 const size_t end_region =
2516 sd.addr_to_region_idx(sd.region_align_up(new_top));
2517
2518 for (size_t cur = end_region - 1; cur + 1 > beg_region; --cur) {
2519 if (sd.region(cur)->claim_unsafe()) {
2520 ParCompactionManager::region_list_push(which, cur);
2521
2522 if (TraceParallelOldGCCompactionPhase && Verbose) {
2523 const size_t count_mod_8 = fillable_regions & 7;
2524 if (count_mod_8 == 0) gclog_or_tty->print("fillable: ");
2525 gclog_or_tty->print(" " SIZE_FORMAT_W(7), cur);
2526 if (count_mod_8 == 7) gclog_or_tty->cr();
2527 }
2528
2529 NOT_PRODUCT(++fillable_regions;)
2530
2531 // Assign regions to tasks in round-robin fashion.
2532 if (++which == task_count) {
2533 assert(which <= parallel_gc_threads,
2534 "Inconsistent number of workers");
2535 which = 0;
2536 }
2537 }
2538 }
2539 }
2540
2541 if (TraceParallelOldGCCompactionPhase) {
2542 if (Verbose && (fillable_regions & 7) != 0) gclog_or_tty->cr();
2543 gclog_or_tty->print_cr(SIZE_FORMAT " initially fillable regions", fillable_regions);
2544 }
2545 }
2546
2547 #define PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING 4
2548
2549 void PSParallelCompact::enqueue_dense_prefix_tasks(GCTaskQueue* q,
2550 uint parallel_gc_threads) {
2551 GCTraceTime tm("dense prefix task setup", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2552
2553 ParallelCompactData& sd = PSParallelCompact::summary_data();
2554
2555 // Iterate over all the spaces adding tasks for updating
2556 // regions in the dense prefix. Assume that 1 gc thread
2557 // will work on opening the gaps and the remaining gc threads
2558 // will work on the dense prefix.
2559 unsigned int space_id;
2560 for (space_id = old_space_id; space_id < last_space_id; ++ space_id) {
2561 HeapWord* const dense_prefix_end = _space_info[space_id].dense_prefix();
2562 const MutableSpace* const space = _space_info[space_id].space();
2563
2564 if (dense_prefix_end == space->bottom()) {
2565 // There is no dense prefix for this space.
2566 continue;
2567 }
2568
2569 // The dense prefix is before this region.
2570 size_t region_index_end_dense_prefix =
2571 sd.addr_to_region_idx(dense_prefix_end);
2572 RegionData* const dense_prefix_cp =
2573 sd.region(region_index_end_dense_prefix);
2574 assert(dense_prefix_end == space->end() ||
2575 dense_prefix_cp->available() ||
2576 dense_prefix_cp->claimed(),
2577 "The region after the dense prefix should always be ready to fill");
2578
2579 size_t region_index_start = sd.addr_to_region_idx(space->bottom());
2580
2581 // Is there dense prefix work?
2582 size_t total_dense_prefix_regions =
2583 region_index_end_dense_prefix - region_index_start;
2584 // How many regions of the dense prefix should be given to
2585 // each thread?
2586 if (total_dense_prefix_regions > 0) {
2587 uint tasks_for_dense_prefix = 1;
2588 if (total_dense_prefix_regions <=
2589 (parallel_gc_threads * PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING)) {
2590 // Don't over partition. This assumes that
2591 // PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING is a small integer value
2592 // so there are not many regions to process.
2593 tasks_for_dense_prefix = parallel_gc_threads;
2594 } else {
2595 // Over partition
2596 tasks_for_dense_prefix = parallel_gc_threads *
2597 PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING;
2598 }
2599 size_t regions_per_thread = total_dense_prefix_regions /
2600 tasks_for_dense_prefix;
2601 // Give each thread at least 1 region.
2602 if (regions_per_thread == 0) {
2603 regions_per_thread = 1;
2604 }
2605
2606 for (uint k = 0; k < tasks_for_dense_prefix; k++) {
2607 if (region_index_start >= region_index_end_dense_prefix) {
2608 break;
2609 }
2610 // region_index_end is not processed
2611 size_t region_index_end = MIN2(region_index_start + regions_per_thread,
2612 region_index_end_dense_prefix);
2613 q->enqueue(new UpdateDensePrefixTask(SpaceId(space_id),
2614 region_index_start,
2615 region_index_end));
2616 region_index_start = region_index_end;
2617 }
2618 }
2619 // This gets any part of the dense prefix that did not
2620 // fit evenly.
2621 if (region_index_start < region_index_end_dense_prefix) {
2622 q->enqueue(new UpdateDensePrefixTask(SpaceId(space_id),
2623 region_index_start,
2624 region_index_end_dense_prefix));
2625 }
2626 }
2627 }
2628
2629 void PSParallelCompact::enqueue_region_stealing_tasks(
2630 GCTaskQueue* q,
2631 ParallelTaskTerminator* terminator_ptr,
2632 uint parallel_gc_threads) {
2633 GCTraceTime tm("steal task setup", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2634
2635 // Once a thread has drained it's stack, it should try to steal regions from
2636 // other threads.
2637 if (parallel_gc_threads > 1) {
2638 for (uint j = 0; j < parallel_gc_threads; j++) {
2639 q->enqueue(new StealRegionCompactionTask(terminator_ptr));
2640 }
2641 }
2642 }
2643
2644 #ifdef ASSERT
2645 // Write a histogram of the number of times the block table was filled for a
2646 // region.
2647 void PSParallelCompact::write_block_fill_histogram(outputStream* const out)
2648 {
2649 if (!TraceParallelOldGCCompactionPhase) return;
2650
2651 typedef ParallelCompactData::RegionData rd_t;
2652 ParallelCompactData& sd = summary_data();
2653
2654 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
2655 MutableSpace* const spc = _space_info[id].space();
2656 if (spc->bottom() != spc->top()) {
2657 const rd_t* const beg = sd.addr_to_region_ptr(spc->bottom());
2658 HeapWord* const top_aligned_up = sd.region_align_up(spc->top());
2659 const rd_t* const end = sd.addr_to_region_ptr(top_aligned_up);
2660
2661 size_t histo[5] = { 0, 0, 0, 0, 0 };
2662 const size_t histo_len = sizeof(histo) / sizeof(size_t);
2663 const size_t region_cnt = pointer_delta(end, beg, sizeof(rd_t));
2664
2665 for (const rd_t* cur = beg; cur < end; ++cur) {
2666 ++histo[MIN2(cur->blocks_filled_count(), histo_len - 1)];
2667 }
2668 out->print("%u %-4s" SIZE_FORMAT_W(5), id, space_names[id], region_cnt);
2669 for (size_t i = 0; i < histo_len; ++i) {
2670 out->print(" " SIZE_FORMAT_W(5) " %5.1f%%",
2671 histo[i], 100.0 * histo[i] / region_cnt);
2672 }
2673 out->cr();
2674 }
2675 }
2676 }
2677 #endif // #ifdef ASSERT
2678
2679 void PSParallelCompact::compact() {
2680 // trace("5");
2681 GCTraceTime tm("compaction phase", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2682
2683 ParallelScavengeHeap* heap = ParallelScavengeHeap::heap();
2684 PSOldGen* old_gen = heap->old_gen();
2685 old_gen->start_array()->reset();
2686 uint parallel_gc_threads = heap->gc_task_manager()->workers();
2687 uint active_gc_threads = heap->gc_task_manager()->active_workers();
2688 TaskQueueSetSuper* qset = ParCompactionManager::region_array();
2689 ParallelTaskTerminator terminator(active_gc_threads, qset);
2690
2691 GCTaskQueue* q = GCTaskQueue::create();
2692 enqueue_region_draining_tasks(q, active_gc_threads);
2693 enqueue_dense_prefix_tasks(q, active_gc_threads);
2694 enqueue_region_stealing_tasks(q, &terminator, active_gc_threads);
2695
2696 {
2697 GCTraceTime tm_pc("par compact", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2698
2699 gc_task_manager()->execute_and_wait(q);
2700
2701 #ifdef ASSERT
2702 // Verify that all regions have been processed before the deferred updates.
2703 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
2704 verify_complete(SpaceId(id));
2705 }
2706 #endif
2707 }
2708
2709 {
2710 // Update the deferred objects, if any. Any compaction manager can be used.
2711 GCTraceTime tm_du("deferred updates", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2712 ParCompactionManager* cm = ParCompactionManager::manager_array(0);
2713 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
2714 update_deferred_objects(cm, SpaceId(id));
2715 }
2716 }
2717
2718 DEBUG_ONLY(write_block_fill_histogram(gclog_or_tty));
2719 }
2720
2721 #ifdef ASSERT
2722 void PSParallelCompact::verify_complete(SpaceId space_id) {
2723 // All Regions between space bottom() to new_top() should be marked as filled
2724 // and all Regions between new_top() and top() should be available (i.e.,
2725 // should have been emptied).
2726 ParallelCompactData& sd = summary_data();
2727 SpaceInfo si = _space_info[space_id];
2728 HeapWord* new_top_addr = sd.region_align_up(si.new_top());
2729 HeapWord* old_top_addr = sd.region_align_up(si.space()->top());
2730 const size_t beg_region = sd.addr_to_region_idx(si.space()->bottom());
2731 const size_t new_top_region = sd.addr_to_region_idx(new_top_addr);
2732 const size_t old_top_region = sd.addr_to_region_idx(old_top_addr);
2733
2734 bool issued_a_warning = false;
2735
2736 size_t cur_region;
2737 for (cur_region = beg_region; cur_region < new_top_region; ++cur_region) {
2738 const RegionData* const c = sd.region(cur_region);
2739 if (!c->completed()) {
2740 warning("region " SIZE_FORMAT " not filled: "
2741 "destination_count=%u",
2742 cur_region, c->destination_count());
2743 issued_a_warning = true;
2744 }
2745 }
2746
2747 for (cur_region = new_top_region; cur_region < old_top_region; ++cur_region) {
2748 const RegionData* const c = sd.region(cur_region);
2749 if (!c->available()) {
2750 warning("region " SIZE_FORMAT " not empty: "
2751 "destination_count=%u",
2752 cur_region, c->destination_count());
2753 issued_a_warning = true;
2754 }
2755 }
2756
2757 if (issued_a_warning) {
2758 print_region_ranges();
2759 }
2760 }
2761 #endif // #ifdef ASSERT
2762
2763 inline void UpdateOnlyClosure::do_addr(HeapWord* addr) {
2764 _start_array->allocate_block(addr);
2765 compaction_manager()->update_contents(oop(addr));
2766 }
2767
2768 // Update interior oops in the ranges of regions [beg_region, end_region).
2769 void
2770 PSParallelCompact::update_and_deadwood_in_dense_prefix(ParCompactionManager* cm,
2771 SpaceId space_id,
2772 size_t beg_region,
2773 size_t end_region) {
2774 ParallelCompactData& sd = summary_data();
2775 ParMarkBitMap* const mbm = mark_bitmap();
2776
2777 HeapWord* beg_addr = sd.region_to_addr(beg_region);
2778 HeapWord* const end_addr = sd.region_to_addr(end_region);
2779 assert(beg_region <= end_region, "bad region range");
2780 assert(end_addr <= dense_prefix(space_id), "not in the dense prefix");
2781
2782 #ifdef ASSERT
2783 // Claim the regions to avoid triggering an assert when they are marked as
2784 // filled.
2785 for (size_t claim_region = beg_region; claim_region < end_region; ++claim_region) {
2786 assert(sd.region(claim_region)->claim_unsafe(), "claim() failed");
2787 }
2788 #endif // #ifdef ASSERT
2789
2790 if (beg_addr != space(space_id)->bottom()) {
2791 // Find the first live object or block of dead space that *starts* in this
2792 // range of regions. If a partial object crosses onto the region, skip it;
2793 // it will be marked for 'deferred update' when the object head is
2794 // processed. If dead space crosses onto the region, it is also skipped; it
2795 // will be filled when the prior region is processed. If neither of those
2796 // apply, the first word in the region is the start of a live object or dead
2797 // space.
2798 assert(beg_addr > space(space_id)->bottom(), "sanity");
2799 const RegionData* const cp = sd.region(beg_region);
2800 if (cp->partial_obj_size() != 0) {
2801 beg_addr = sd.partial_obj_end(beg_region);
2802 } else if (dead_space_crosses_boundary(cp, mbm->addr_to_bit(beg_addr))) {
2803 beg_addr = mbm->find_obj_beg(beg_addr, end_addr);
2804 }
2805 }
2806
2807 if (beg_addr < end_addr) {
2808 // A live object or block of dead space starts in this range of Regions.
2809 HeapWord* const dense_prefix_end = dense_prefix(space_id);
2810
2811 // Create closures and iterate.
2812 UpdateOnlyClosure update_closure(mbm, cm, space_id);
2813 FillClosure fill_closure(cm, space_id);
2814 ParMarkBitMap::IterationStatus status;
2815 status = mbm->iterate(&update_closure, &fill_closure, beg_addr, end_addr,
2816 dense_prefix_end);
2817 if (status == ParMarkBitMap::incomplete) {
2818 update_closure.do_addr(update_closure.source());
2819 }
2820 }
2821
2822 // Mark the regions as filled.
2823 RegionData* const beg_cp = sd.region(beg_region);
2824 RegionData* const end_cp = sd.region(end_region);
2825 for (RegionData* cp = beg_cp; cp < end_cp; ++cp) {
2826 cp->set_completed();
2827 }
2828 }
2829
2830 // Return the SpaceId for the space containing addr. If addr is not in the
2831 // heap, last_space_id is returned. In debug mode it expects the address to be
2832 // in the heap and asserts such.
2833 PSParallelCompact::SpaceId PSParallelCompact::space_id(HeapWord* addr) {
2834 assert(ParallelScavengeHeap::heap()->is_in_reserved(addr), "addr not in the heap");
2835
2836 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
2837 if (_space_info[id].space()->contains(addr)) {
2838 return SpaceId(id);
2839 }
2840 }
2841
2842 assert(false, "no space contains the addr");
2843 return last_space_id;
2844 }
2845
2846 void PSParallelCompact::update_deferred_objects(ParCompactionManager* cm,
2847 SpaceId id) {
2848 assert(id < last_space_id, "bad space id");
2849
2850 ParallelCompactData& sd = summary_data();
2851 const SpaceInfo* const space_info = _space_info + id;
2852 ObjectStartArray* const start_array = space_info->start_array();
2853
2854 const MutableSpace* const space = space_info->space();
2855 assert(space_info->dense_prefix() >= space->bottom(), "dense_prefix not set");
2856 HeapWord* const beg_addr = space_info->dense_prefix();
2857 HeapWord* const end_addr = sd.region_align_up(space_info->new_top());
2858
2859 const RegionData* const beg_region = sd.addr_to_region_ptr(beg_addr);
2860 const RegionData* const end_region = sd.addr_to_region_ptr(end_addr);
2861 const RegionData* cur_region;
2862 for (cur_region = beg_region; cur_region < end_region; ++cur_region) {
2863 HeapWord* const addr = cur_region->deferred_obj_addr();
2864 if (addr != NULL) {
2865 if (start_array != NULL) {
2866 start_array->allocate_block(addr);
2867 }
2868 cm->update_contents(oop(addr));
2869 assert(oop(addr)->is_oop_or_null(), err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(oop(addr))));
2870 }
2871 }
2872 }
2873
2874 // Skip over count live words starting from beg, and return the address of the
2875 // next live word. Unless marked, the word corresponding to beg is assumed to
2876 // be dead. Callers must either ensure beg does not correspond to the middle of
2877 // an object, or account for those live words in some other way. Callers must
2878 // also ensure that there are enough live words in the range [beg, end) to skip.
2879 HeapWord*
2880 PSParallelCompact::skip_live_words(HeapWord* beg, HeapWord* end, size_t count)
2881 {
2882 assert(count > 0, "sanity");
2883
2884 ParMarkBitMap* m = mark_bitmap();
2885 idx_t bits_to_skip = m->words_to_bits(count);
2886 idx_t cur_beg = m->addr_to_bit(beg);
2887 const idx_t search_end = BitMap::word_align_up(m->addr_to_bit(end));
2888
2889 do {
2890 cur_beg = m->find_obj_beg(cur_beg, search_end);
2891 idx_t cur_end = m->find_obj_end(cur_beg, search_end);
2892 const size_t obj_bits = cur_end - cur_beg + 1;
2893 if (obj_bits > bits_to_skip) {
2894 return m->bit_to_addr(cur_beg + bits_to_skip);
2895 }
2896 bits_to_skip -= obj_bits;
2897 cur_beg = cur_end + 1;
2898 } while (bits_to_skip > 0);
2899
2900 // Skipping the desired number of words landed just past the end of an object.
2901 // Find the start of the next object.
2902 cur_beg = m->find_obj_beg(cur_beg, search_end);
2903 assert(cur_beg < m->addr_to_bit(end), "not enough live words to skip");
2904 return m->bit_to_addr(cur_beg);
2905 }
2906
2907 HeapWord* PSParallelCompact::first_src_addr(HeapWord* const dest_addr,
2908 SpaceId src_space_id,
2909 size_t src_region_idx)
2910 {
2911 assert(summary_data().is_region_aligned(dest_addr), "not aligned");
2912
2913 const SplitInfo& split_info = _space_info[src_space_id].split_info();
2914 if (split_info.dest_region_addr() == dest_addr) {
2915 // The partial object ending at the split point contains the first word to
2916 // be copied to dest_addr.
2917 return split_info.first_src_addr();
2918 }
2919
2920 const ParallelCompactData& sd = summary_data();
2921 ParMarkBitMap* const bitmap = mark_bitmap();
2922 const size_t RegionSize = ParallelCompactData::RegionSize;
2923
2924 assert(sd.is_region_aligned(dest_addr), "not aligned");
2925 const RegionData* const src_region_ptr = sd.region(src_region_idx);
2926 const size_t partial_obj_size = src_region_ptr->partial_obj_size();
2927 HeapWord* const src_region_destination = src_region_ptr->destination();
2928
2929 assert(dest_addr >= src_region_destination, "wrong src region");
2930 assert(src_region_ptr->data_size() > 0, "src region cannot be empty");
2931
2932 HeapWord* const src_region_beg = sd.region_to_addr(src_region_idx);
2933 HeapWord* const src_region_end = src_region_beg + RegionSize;
2934
2935 HeapWord* addr = src_region_beg;
2936 if (dest_addr == src_region_destination) {
2937 // Return the first live word in the source region.
2938 if (partial_obj_size == 0) {
2939 addr = bitmap->find_obj_beg(addr, src_region_end);
2940 assert(addr < src_region_end, "no objects start in src region");
2941 }
2942 return addr;
2943 }
2944
2945 // Must skip some live data.
2946 size_t words_to_skip = dest_addr - src_region_destination;
2947 assert(src_region_ptr->data_size() > words_to_skip, "wrong src region");
2948
2949 if (partial_obj_size >= words_to_skip) {
2950 // All the live words to skip are part of the partial object.
2951 addr += words_to_skip;
2952 if (partial_obj_size == words_to_skip) {
2953 // Find the first live word past the partial object.
2954 addr = bitmap->find_obj_beg(addr, src_region_end);
2955 assert(addr < src_region_end, "wrong src region");
2956 }
2957 return addr;
2958 }
2959
2960 // Skip over the partial object (if any).
2961 if (partial_obj_size != 0) {
2962 words_to_skip -= partial_obj_size;
2963 addr += partial_obj_size;
2964 }
2965
2966 // Skip over live words due to objects that start in the region.
2967 addr = skip_live_words(addr, src_region_end, words_to_skip);
2968 assert(addr < src_region_end, "wrong src region");
2969 return addr;
2970 }
2971
2972 void PSParallelCompact::decrement_destination_counts(ParCompactionManager* cm,
2973 SpaceId src_space_id,
2974 size_t beg_region,
2975 HeapWord* end_addr)
2976 {
2977 ParallelCompactData& sd = summary_data();
2978
2979 #ifdef ASSERT
2980 MutableSpace* const src_space = _space_info[src_space_id].space();
2981 HeapWord* const beg_addr = sd.region_to_addr(beg_region);
2982 assert(src_space->contains(beg_addr) || beg_addr == src_space->end(),
2983 "src_space_id does not match beg_addr");
2984 assert(src_space->contains(end_addr) || end_addr == src_space->end(),
2985 "src_space_id does not match end_addr");
2986 #endif // #ifdef ASSERT
2987
2988 RegionData* const beg = sd.region(beg_region);
2989 RegionData* const end = sd.addr_to_region_ptr(sd.region_align_up(end_addr));
2990
2991 // Regions up to new_top() are enqueued if they become available.
2992 HeapWord* const new_top = _space_info[src_space_id].new_top();
2993 RegionData* const enqueue_end =
2994 sd.addr_to_region_ptr(sd.region_align_up(new_top));
2995
2996 for (RegionData* cur = beg; cur < end; ++cur) {
2997 assert(cur->data_size() > 0, "region must have live data");
2998 cur->decrement_destination_count();
2999 if (cur < enqueue_end && cur->available() && cur->claim()) {
3000 cm->push_region(sd.region(cur));
3001 }
3002 }
3003 }
3004
3005 size_t PSParallelCompact::next_src_region(MoveAndUpdateClosure& closure,
3006 SpaceId& src_space_id,
3007 HeapWord*& src_space_top,
3008 HeapWord* end_addr)
3009 {
3010 typedef ParallelCompactData::RegionData RegionData;
3011
3012 ParallelCompactData& sd = PSParallelCompact::summary_data();
3013 const size_t region_size = ParallelCompactData::RegionSize;
3014
3015 size_t src_region_idx = 0;
3016
3017 // Skip empty regions (if any) up to the top of the space.
3018 HeapWord* const src_aligned_up = sd.region_align_up(end_addr);
3019 RegionData* src_region_ptr = sd.addr_to_region_ptr(src_aligned_up);
3020 HeapWord* const top_aligned_up = sd.region_align_up(src_space_top);
3021 const RegionData* const top_region_ptr =
3022 sd.addr_to_region_ptr(top_aligned_up);
3023 while (src_region_ptr < top_region_ptr && src_region_ptr->data_size() == 0) {
3024 ++src_region_ptr;
3025 }
3026
3027 if (src_region_ptr < top_region_ptr) {
3028 // The next source region is in the current space. Update src_region_idx
3029 // and the source address to match src_region_ptr.
3030 src_region_idx = sd.region(src_region_ptr);
3031 HeapWord* const src_region_addr = sd.region_to_addr(src_region_idx);
3032 if (src_region_addr > closure.source()) {
3033 closure.set_source(src_region_addr);
3034 }
3035 return src_region_idx;
3036 }
3037
3038 // Switch to a new source space and find the first non-empty region.
3039 unsigned int space_id = src_space_id + 1;
3040 assert(space_id < last_space_id, "not enough spaces");
3041
3042 HeapWord* const destination = closure.destination();
3043
3044 do {
3045 MutableSpace* space = _space_info[space_id].space();
3046 HeapWord* const bottom = space->bottom();
3047 const RegionData* const bottom_cp = sd.addr_to_region_ptr(bottom);
3048
3049 // Iterate over the spaces that do not compact into themselves.
3050 if (bottom_cp->destination() != bottom) {
3051 HeapWord* const top_aligned_up = sd.region_align_up(space->top());
3052 const RegionData* const top_cp = sd.addr_to_region_ptr(top_aligned_up);
3053
3054 for (const RegionData* src_cp = bottom_cp; src_cp < top_cp; ++src_cp) {
3055 if (src_cp->live_obj_size() > 0) {
3056 // Found it.
3057 assert(src_cp->destination() == destination,
3058 "first live obj in the space must match the destination");
3059 assert(src_cp->partial_obj_size() == 0,
3060 "a space cannot begin with a partial obj");
3061
3062 src_space_id = SpaceId(space_id);
3063 src_space_top = space->top();
3064 const size_t src_region_idx = sd.region(src_cp);
3065 closure.set_source(sd.region_to_addr(src_region_idx));
3066 return src_region_idx;
3067 } else {
3068 assert(src_cp->data_size() == 0, "sanity");
3069 }
3070 }
3071 }
3072 } while (++space_id < last_space_id);
3073
3074 assert(false, "no source region was found");
3075 return 0;
3076 }
3077
3078 void PSParallelCompact::fill_region(ParCompactionManager* cm, size_t region_idx)
3079 {
3080 typedef ParMarkBitMap::IterationStatus IterationStatus;
3081 const size_t RegionSize = ParallelCompactData::RegionSize;
3082 ParMarkBitMap* const bitmap = mark_bitmap();
3083 ParallelCompactData& sd = summary_data();
3084 RegionData* const region_ptr = sd.region(region_idx);
3085
3086 // Get the items needed to construct the closure.
3087 HeapWord* dest_addr = sd.region_to_addr(region_idx);
3088 SpaceId dest_space_id = space_id(dest_addr);
3089 ObjectStartArray* start_array = _space_info[dest_space_id].start_array();
3090 HeapWord* new_top = _space_info[dest_space_id].new_top();
3091 assert(dest_addr < new_top, "sanity");
3092 const size_t words = MIN2(pointer_delta(new_top, dest_addr), RegionSize);
3093
3094 // Get the source region and related info.
3095 size_t src_region_idx = region_ptr->source_region();
3096 SpaceId src_space_id = space_id(sd.region_to_addr(src_region_idx));
3097 HeapWord* src_space_top = _space_info[src_space_id].space()->top();
3098
3099 MoveAndUpdateClosure closure(bitmap, cm, start_array, dest_addr, words);
3100 closure.set_source(first_src_addr(dest_addr, src_space_id, src_region_idx));
3101
3102 // Adjust src_region_idx to prepare for decrementing destination counts (the
3103 // destination count is not decremented when a region is copied to itself).
3104 if (src_region_idx == region_idx) {
3105 src_region_idx += 1;
3106 }
3107
3108 if (bitmap->is_unmarked(closure.source())) {
3109 // The first source word is in the middle of an object; copy the remainder
3110 // of the object or as much as will fit. The fact that pointer updates were
3111 // deferred will be noted when the object header is processed.
3112 HeapWord* const old_src_addr = closure.source();
3113 closure.copy_partial_obj();
3114 if (closure.is_full()) {
3115 decrement_destination_counts(cm, src_space_id, src_region_idx,
3116 closure.source());
3117 region_ptr->set_deferred_obj_addr(NULL);
3118 region_ptr->set_completed();
3119 return;
3120 }
3121
3122 HeapWord* const end_addr = sd.region_align_down(closure.source());
3123 if (sd.region_align_down(old_src_addr) != end_addr) {
3124 // The partial object was copied from more than one source region.
3125 decrement_destination_counts(cm, src_space_id, src_region_idx, end_addr);
3126
3127 // Move to the next source region, possibly switching spaces as well. All
3128 // args except end_addr may be modified.
3129 src_region_idx = next_src_region(closure, src_space_id, src_space_top,
3130 end_addr);
3131 }
3132 }
3133
3134 do {
3135 HeapWord* const cur_addr = closure.source();
3136 HeapWord* const end_addr = MIN2(sd.region_align_up(cur_addr + 1),
3137 src_space_top);
3138 IterationStatus status = bitmap->iterate(&closure, cur_addr, end_addr);
3139
3140 if (status == ParMarkBitMap::incomplete) {
3141 // The last obj that starts in the source region does not end in the
3142 // region.
3143 assert(closure.source() < end_addr, "sanity");
3144 HeapWord* const obj_beg = closure.source();
3145 HeapWord* const range_end = MIN2(obj_beg + closure.words_remaining(),
3146 src_space_top);
3147 HeapWord* const obj_end = bitmap->find_obj_end(obj_beg, range_end);
3148 if (obj_end < range_end) {
3149 // The end was found; the entire object will fit.
3150 status = closure.do_addr(obj_beg, bitmap->obj_size(obj_beg, obj_end));
3151 assert(status != ParMarkBitMap::would_overflow, "sanity");
3152 } else {
3153 // The end was not found; the object will not fit.
3154 assert(range_end < src_space_top, "obj cannot cross space boundary");
3155 status = ParMarkBitMap::would_overflow;
3156 }
3157 }
3158
3159 if (status == ParMarkBitMap::would_overflow) {
3160 // The last object did not fit. Note that interior oop updates were
3161 // deferred, then copy enough of the object to fill the region.
3162 region_ptr->set_deferred_obj_addr(closure.destination());
3163 status = closure.copy_until_full(); // copies from closure.source()
3164
3165 decrement_destination_counts(cm, src_space_id, src_region_idx,
3166 closure.source());
3167 region_ptr->set_completed();
3168 return;
3169 }
3170
3171 if (status == ParMarkBitMap::full) {
3172 decrement_destination_counts(cm, src_space_id, src_region_idx,
3173 closure.source());
3174 region_ptr->set_deferred_obj_addr(NULL);
3175 region_ptr->set_completed();
3176 return;
3177 }
3178
3179 decrement_destination_counts(cm, src_space_id, src_region_idx, end_addr);
3180
3181 // Move to the next source region, possibly switching spaces as well. All
3182 // args except end_addr may be modified.
3183 src_region_idx = next_src_region(closure, src_space_id, src_space_top,
3184 end_addr);
3185 } while (true);
3186 }
3187
3188 void PSParallelCompact::fill_blocks(size_t region_idx)
3189 {
3190 // Fill in the block table elements for the specified region. Each block
3191 // table element holds the number of live words in the region that are to the
3192 // left of the first object that starts in the block. Thus only blocks in
3193 // which an object starts need to be filled.
3194 //
3195 // The algorithm scans the section of the bitmap that corresponds to the
3196 // region, keeping a running total of the live words. When an object start is
3197 // found, if it's the first to start in the block that contains it, the
3198 // current total is written to the block table element.
3199 const size_t Log2BlockSize = ParallelCompactData::Log2BlockSize;
3200 const size_t Log2RegionSize = ParallelCompactData::Log2RegionSize;
3201 const size_t RegionSize = ParallelCompactData::RegionSize;
3202
3203 ParallelCompactData& sd = summary_data();
3204 const size_t partial_obj_size = sd.region(region_idx)->partial_obj_size();
3205 if (partial_obj_size >= RegionSize) {
3206 return; // No objects start in this region.
3207 }
3208
3209 // Ensure the first loop iteration decides that the block has changed.
3210 size_t cur_block = sd.block_count();
3211
3212 const ParMarkBitMap* const bitmap = mark_bitmap();
3213
3214 const size_t Log2BitsPerBlock = Log2BlockSize - LogMinObjAlignment;
3215 assert((size_t)1 << Log2BitsPerBlock ==
3216 bitmap->words_to_bits(ParallelCompactData::BlockSize), "sanity");
3217
3218 size_t beg_bit = bitmap->words_to_bits(region_idx << Log2RegionSize);
3219 const size_t range_end = beg_bit + bitmap->words_to_bits(RegionSize);
3220 size_t live_bits = bitmap->words_to_bits(partial_obj_size);
3221 beg_bit = bitmap->find_obj_beg(beg_bit + live_bits, range_end);
3222 while (beg_bit < range_end) {
3223 const size_t new_block = beg_bit >> Log2BitsPerBlock;
3224 if (new_block != cur_block) {
3225 cur_block = new_block;
3226 sd.block(cur_block)->set_offset(bitmap->bits_to_words(live_bits));
3227 }
3228
3229 const size_t end_bit = bitmap->find_obj_end(beg_bit, range_end);
3230 if (end_bit < range_end - 1) {
3231 live_bits += end_bit - beg_bit + 1;
3232 beg_bit = bitmap->find_obj_beg(end_bit + 1, range_end);
3233 } else {
3234 return;
3235 }
3236 }
3237 }
3238
3239 void
3240 PSParallelCompact::move_and_update(ParCompactionManager* cm, SpaceId space_id) {
3241 const MutableSpace* sp = space(space_id);
3242 if (sp->is_empty()) {
3243 return;
3244 }
3245
3246 ParallelCompactData& sd = PSParallelCompact::summary_data();
3247 ParMarkBitMap* const bitmap = mark_bitmap();
3248 HeapWord* const dp_addr = dense_prefix(space_id);
3249 HeapWord* beg_addr = sp->bottom();
3250 HeapWord* end_addr = sp->top();
3251
3252 assert(beg_addr <= dp_addr && dp_addr <= end_addr, "bad dense prefix");
3253
3254 const size_t beg_region = sd.addr_to_region_idx(beg_addr);
3255 const size_t dp_region = sd.addr_to_region_idx(dp_addr);
3256 if (beg_region < dp_region) {
3257 update_and_deadwood_in_dense_prefix(cm, space_id, beg_region, dp_region);
3258 }
3259
3260 // The destination of the first live object that starts in the region is one
3261 // past the end of the partial object entering the region (if any).
3262 HeapWord* const dest_addr = sd.partial_obj_end(dp_region);
3263 HeapWord* const new_top = _space_info[space_id].new_top();
3264 assert(new_top >= dest_addr, "bad new_top value");
3265 const size_t words = pointer_delta(new_top, dest_addr);
3266
3267 if (words > 0) {
3268 ObjectStartArray* start_array = _space_info[space_id].start_array();
3269 MoveAndUpdateClosure closure(bitmap, cm, start_array, dest_addr, words);
3270
3271 ParMarkBitMap::IterationStatus status;
3272 status = bitmap->iterate(&closure, dest_addr, end_addr);
3273 assert(status == ParMarkBitMap::full, "iteration not complete");
3274 assert(bitmap->find_obj_beg(closure.source(), end_addr) == end_addr,
3275 "live objects skipped because closure is full");
3276 }
3277 }
3278
3279 jlong PSParallelCompact::millis_since_last_gc() {
3280 // We need a monotonically non-decreasing time in ms but
3281 // os::javaTimeMillis() does not guarantee monotonicity.
3282 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
3283 jlong ret_val = now - _time_of_last_gc;
3284 // XXX See note in genCollectedHeap::millis_since_last_gc().
3285 if (ret_val < 0) {
3286 NOT_PRODUCT(warning("time warp: " JLONG_FORMAT, ret_val);)
3287 return 0;
3288 }
3289 return ret_val;
3290 }
3291
3292 void PSParallelCompact::reset_millis_since_last_gc() {
3293 // We need a monotonically non-decreasing time in ms but
3294 // os::javaTimeMillis() does not guarantee monotonicity.
3295 _time_of_last_gc = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
3296 }
3297
3298 ParMarkBitMap::IterationStatus MoveAndUpdateClosure::copy_until_full()
3299 {
3300 if (source() != destination()) {
3301 DEBUG_ONLY(PSParallelCompact::check_new_location(source(), destination());)
3302 Copy::aligned_conjoint_words(source(), destination(), words_remaining());
3303 }
3304 update_state(words_remaining());
3305 assert(is_full(), "sanity");
3306 return ParMarkBitMap::full;
3307 }
3308
3309 void MoveAndUpdateClosure::copy_partial_obj()
3310 {
3311 size_t words = words_remaining();
3312
3313 HeapWord* const range_end = MIN2(source() + words, bitmap()->region_end());
3314 HeapWord* const end_addr = bitmap()->find_obj_end(source(), range_end);
3315 if (end_addr < range_end) {
3316 words = bitmap()->obj_size(source(), end_addr);
3317 }
3318
3319 // This test is necessary; if omitted, the pointer updates to a partial object
3320 // that crosses the dense prefix boundary could be overwritten.
3321 if (source() != destination()) {
3322 DEBUG_ONLY(PSParallelCompact::check_new_location(source(), destination());)
3323 Copy::aligned_conjoint_words(source(), destination(), words);
3324 }
3325 update_state(words);
3326 }
3327
3328 void InstanceKlass::oop_pc_update_pointers(oop obj) {
3329 oop_oop_iterate_oop_maps<true>(obj, PSParallelCompact::adjust_pointer_closure());
3330 }
3331
3332 void InstanceMirrorKlass::oop_pc_update_pointers(oop obj) {
3333 InstanceKlass::oop_pc_update_pointers(obj);
3334
3335 oop_oop_iterate_statics<true>(obj, PSParallelCompact::adjust_pointer_closure());
3336 }
3337
3338 void InstanceClassLoaderKlass::oop_pc_update_pointers(oop obj) {
3339 InstanceKlass::oop_pc_update_pointers(obj);
3340 }
3341
3342 #ifdef ASSERT
3343 template <class T> static void trace_reference_gc(const char *s, oop obj,
3344 T* referent_addr,
3345 T* next_addr,
3346 T* discovered_addr) {
3347 if(TraceReferenceGC && PrintGCDetails) {
3348 gclog_or_tty->print_cr("%s obj " PTR_FORMAT, s, p2i(obj));
3349 gclog_or_tty->print_cr(" referent_addr/* " PTR_FORMAT " / "
3350 PTR_FORMAT, p2i(referent_addr),
3351 referent_addr ? p2i(oopDesc::load_decode_heap_oop(referent_addr)) : NULL);
3352 gclog_or_tty->print_cr(" next_addr/* " PTR_FORMAT " / "
3353 PTR_FORMAT, p2i(next_addr),
3354 next_addr ? p2i(oopDesc::load_decode_heap_oop(next_addr)) : NULL);
3355 gclog_or_tty->print_cr(" discovered_addr/* " PTR_FORMAT " / "
3356 PTR_FORMAT, p2i(discovered_addr),
3357 discovered_addr ? p2i(oopDesc::load_decode_heap_oop(discovered_addr)) : NULL);
3358 }
3359 }
3360 #endif
3361
3362 template <class T>
3363 static void oop_pc_update_pointers_specialized(oop obj) {
3364 T* referent_addr = (T*)java_lang_ref_Reference::referent_addr(obj);
3365 PSParallelCompact::adjust_pointer(referent_addr);
3366 T* next_addr = (T*)java_lang_ref_Reference::next_addr(obj);
3367 PSParallelCompact::adjust_pointer(next_addr);
3368 T* discovered_addr = (T*)java_lang_ref_Reference::discovered_addr(obj);
3369 PSParallelCompact::adjust_pointer(discovered_addr);
3370 debug_only(trace_reference_gc("InstanceRefKlass::oop_update_ptrs", obj,
3371 referent_addr, next_addr, discovered_addr);)
3372 }
3373
3374 void InstanceRefKlass::oop_pc_update_pointers(oop obj) {
3375 InstanceKlass::oop_pc_update_pointers(obj);
3376
3377 if (UseCompressedOops) {
3378 oop_pc_update_pointers_specialized<narrowOop>(obj);
3379 } else {
3380 oop_pc_update_pointers_specialized<oop>(obj);
3381 }
3382 }
3383
3384 void ObjArrayKlass::oop_pc_update_pointers(oop obj) {
3385 assert(obj->is_objArray(), "obj must be obj array");
3386 oop_oop_iterate_elements<true>(objArrayOop(obj), PSParallelCompact::adjust_pointer_closure());
3387 }
3388
3389 void TypeArrayKlass::oop_pc_update_pointers(oop obj) {
3390 assert(obj->is_typeArray(),"must be a type array");
3391 }
3392
3393 ParMarkBitMapClosure::IterationStatus
3394 MoveAndUpdateClosure::do_addr(HeapWord* addr, size_t words) {
3395 assert(destination() != NULL, "sanity");
3396 assert(bitmap()->obj_size(addr) == words, "bad size");
3397
3398 _source = addr;
3399 assert(PSParallelCompact::summary_data().calc_new_pointer(source()) ==
3400 destination(), "wrong destination");
3401
3402 if (words > words_remaining()) {
3403 return ParMarkBitMap::would_overflow;
3404 }
3405
3406 // The start_array must be updated even if the object is not moving.
3407 if (_start_array != NULL) {
3408 _start_array->allocate_block(destination());
3409 }
3410
3411 if (destination() != source()) {
3412 DEBUG_ONLY(PSParallelCompact::check_new_location(source(), destination());)
3413 Copy::aligned_conjoint_words(source(), destination(), words);
3414 }
3415
3416 oop moved_oop = (oop) destination();
3417 compaction_manager()->update_contents(moved_oop);
3418 assert(moved_oop->is_oop_or_null(), err_msg("Expected an oop or NULL at " PTR_FORMAT, p2i(moved_oop)));
3419
3420 update_state(words);
3421 assert(destination() == (HeapWord*)moved_oop + moved_oop->size(), "sanity");
3422 return is_full() ? ParMarkBitMap::full : ParMarkBitMap::incomplete;
3423 }
3424
3425 UpdateOnlyClosure::UpdateOnlyClosure(ParMarkBitMap* mbm,
3426 ParCompactionManager* cm,
3427 PSParallelCompact::SpaceId space_id) :
3428 ParMarkBitMapClosure(mbm, cm),
3429 _space_id(space_id),
3430 _start_array(PSParallelCompact::start_array(space_id))
3431 {
3432 }
3433
3434 // Updates the references in the object to their new values.
3435 ParMarkBitMapClosure::IterationStatus
3436 UpdateOnlyClosure::do_addr(HeapWord* addr, size_t words) {
3437 do_addr(addr);
3438 return ParMarkBitMap::incomplete;
3439 }