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rev 7125 : 7176220: 'Full GC' events miss date stamp information occasionally
Summary: Move date stamp logic into GCTraceTime
Reviewed-by: brutisso, tschatzl
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--- old/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.cpp
+++ new/hotspot/src/share/vm/gc_implementation/parallelScavenge/psParallelCompact.cpp
1 1 /*
2 2 * Copyright (c) 2005, 2014, Oracle and/or its affiliates. All rights reserved.
3 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 4 *
5 5 * This code is free software; you can redistribute it and/or modify it
6 6 * under the terms of the GNU General Public License version 2 only, as
7 7 * published by the Free Software Foundation.
8 8 *
9 9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 12 * version 2 for more details (a copy is included in the LICENSE file that
13 13 * accompanied this code).
14 14 *
15 15 * You should have received a copy of the GNU General Public License version
16 16 * 2 along with this work; if not, write to the Free Software Foundation,
17 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 18 *
19 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 20 * or visit www.oracle.com if you need additional information or have any
21 21 * questions.
22 22 *
23 23 */
24 24
25 25 #include "precompiled.hpp"
26 26 #include "classfile/symbolTable.hpp"
27 27 #include "classfile/systemDictionary.hpp"
28 28 #include "code/codeCache.hpp"
29 29 #include "gc_implementation/parallelScavenge/gcTaskManager.hpp"
30 30 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.inline.hpp"
31 31 #include "gc_implementation/parallelScavenge/pcTasks.hpp"
32 32 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
33 33 #include "gc_implementation/parallelScavenge/psCompactionManager.inline.hpp"
34 34 #include "gc_implementation/parallelScavenge/psMarkSweep.hpp"
35 35 #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp"
36 36 #include "gc_implementation/parallelScavenge/psOldGen.hpp"
37 37 #include "gc_implementation/parallelScavenge/psParallelCompact.hpp"
38 38 #include "gc_implementation/parallelScavenge/psPromotionManager.inline.hpp"
39 39 #include "gc_implementation/parallelScavenge/psScavenge.hpp"
40 40 #include "gc_implementation/parallelScavenge/psYoungGen.hpp"
41 41 #include "gc_implementation/shared/gcHeapSummary.hpp"
42 42 #include "gc_implementation/shared/gcTimer.hpp"
43 43 #include "gc_implementation/shared/gcTrace.hpp"
44 44 #include "gc_implementation/shared/gcTraceTime.hpp"
45 45 #include "gc_implementation/shared/isGCActiveMark.hpp"
46 46 #include "gc_interface/gcCause.hpp"
47 47 #include "memory/gcLocker.inline.hpp"
48 48 #include "memory/referencePolicy.hpp"
49 49 #include "memory/referenceProcessor.hpp"
50 50 #include "oops/methodData.hpp"
51 51 #include "oops/oop.inline.hpp"
52 52 #include "oops/oop.pcgc.inline.hpp"
53 53 #include "runtime/fprofiler.hpp"
54 54 #include "runtime/safepoint.hpp"
55 55 #include "runtime/vmThread.hpp"
56 56 #include "services/management.hpp"
57 57 #include "services/memoryService.hpp"
58 58 #include "services/memTracker.hpp"
59 59 #include "utilities/events.hpp"
60 60 #include "utilities/stack.inline.hpp"
61 61
62 62 #include <math.h>
63 63
64 64 PRAGMA_FORMAT_MUTE_WARNINGS_FOR_GCC
65 65
66 66 // All sizes are in HeapWords.
67 67 const size_t ParallelCompactData::Log2RegionSize = 16; // 64K words
68 68 const size_t ParallelCompactData::RegionSize = (size_t)1 << Log2RegionSize;
69 69 const size_t ParallelCompactData::RegionSizeBytes =
70 70 RegionSize << LogHeapWordSize;
71 71 const size_t ParallelCompactData::RegionSizeOffsetMask = RegionSize - 1;
72 72 const size_t ParallelCompactData::RegionAddrOffsetMask = RegionSizeBytes - 1;
73 73 const size_t ParallelCompactData::RegionAddrMask = ~RegionAddrOffsetMask;
74 74
75 75 const size_t ParallelCompactData::Log2BlockSize = 7; // 128 words
76 76 const size_t ParallelCompactData::BlockSize = (size_t)1 << Log2BlockSize;
77 77 const size_t ParallelCompactData::BlockSizeBytes =
78 78 BlockSize << LogHeapWordSize;
79 79 const size_t ParallelCompactData::BlockSizeOffsetMask = BlockSize - 1;
80 80 const size_t ParallelCompactData::BlockAddrOffsetMask = BlockSizeBytes - 1;
81 81 const size_t ParallelCompactData::BlockAddrMask = ~BlockAddrOffsetMask;
82 82
83 83 const size_t ParallelCompactData::BlocksPerRegion = RegionSize / BlockSize;
84 84 const size_t ParallelCompactData::Log2BlocksPerRegion =
85 85 Log2RegionSize - Log2BlockSize;
86 86
87 87 const ParallelCompactData::RegionData::region_sz_t
88 88 ParallelCompactData::RegionData::dc_shift = 27;
89 89
90 90 const ParallelCompactData::RegionData::region_sz_t
91 91 ParallelCompactData::RegionData::dc_mask = ~0U << dc_shift;
92 92
93 93 const ParallelCompactData::RegionData::region_sz_t
94 94 ParallelCompactData::RegionData::dc_one = 0x1U << dc_shift;
95 95
96 96 const ParallelCompactData::RegionData::region_sz_t
97 97 ParallelCompactData::RegionData::los_mask = ~dc_mask;
98 98
99 99 const ParallelCompactData::RegionData::region_sz_t
100 100 ParallelCompactData::RegionData::dc_claimed = 0x8U << dc_shift;
101 101
102 102 const ParallelCompactData::RegionData::region_sz_t
103 103 ParallelCompactData::RegionData::dc_completed = 0xcU << dc_shift;
104 104
105 105 SpaceInfo PSParallelCompact::_space_info[PSParallelCompact::last_space_id];
106 106 bool PSParallelCompact::_print_phases = false;
107 107
108 108 ReferenceProcessor* PSParallelCompact::_ref_processor = NULL;
109 109 Klass* PSParallelCompact::_updated_int_array_klass_obj = NULL;
110 110
111 111 double PSParallelCompact::_dwl_mean;
112 112 double PSParallelCompact::_dwl_std_dev;
113 113 double PSParallelCompact::_dwl_first_term;
114 114 double PSParallelCompact::_dwl_adjustment;
115 115 #ifdef ASSERT
116 116 bool PSParallelCompact::_dwl_initialized = false;
117 117 #endif // #ifdef ASSERT
118 118
119 119 void SplitInfo::record(size_t src_region_idx, size_t partial_obj_size,
120 120 HeapWord* destination)
121 121 {
122 122 assert(src_region_idx != 0, "invalid src_region_idx");
123 123 assert(partial_obj_size != 0, "invalid partial_obj_size argument");
124 124 assert(destination != NULL, "invalid destination argument");
125 125
126 126 _src_region_idx = src_region_idx;
127 127 _partial_obj_size = partial_obj_size;
128 128 _destination = destination;
129 129
130 130 // These fields may not be updated below, so make sure they're clear.
131 131 assert(_dest_region_addr == NULL, "should have been cleared");
132 132 assert(_first_src_addr == NULL, "should have been cleared");
133 133
134 134 // Determine the number of destination regions for the partial object.
135 135 HeapWord* const last_word = destination + partial_obj_size - 1;
136 136 const ParallelCompactData& sd = PSParallelCompact::summary_data();
137 137 HeapWord* const beg_region_addr = sd.region_align_down(destination);
138 138 HeapWord* const end_region_addr = sd.region_align_down(last_word);
139 139
140 140 if (beg_region_addr == end_region_addr) {
141 141 // One destination region.
142 142 _destination_count = 1;
143 143 if (end_region_addr == destination) {
144 144 // The destination falls on a region boundary, thus the first word of the
145 145 // partial object will be the first word copied to the destination region.
146 146 _dest_region_addr = end_region_addr;
147 147 _first_src_addr = sd.region_to_addr(src_region_idx);
148 148 }
149 149 } else {
150 150 // Two destination regions. When copied, the partial object will cross a
151 151 // destination region boundary, so a word somewhere within the partial
152 152 // object will be the first word copied to the second destination region.
153 153 _destination_count = 2;
154 154 _dest_region_addr = end_region_addr;
155 155 const size_t ofs = pointer_delta(end_region_addr, destination);
156 156 assert(ofs < _partial_obj_size, "sanity");
157 157 _first_src_addr = sd.region_to_addr(src_region_idx) + ofs;
158 158 }
159 159 }
160 160
161 161 void SplitInfo::clear()
162 162 {
163 163 _src_region_idx = 0;
164 164 _partial_obj_size = 0;
165 165 _destination = NULL;
166 166 _destination_count = 0;
167 167 _dest_region_addr = NULL;
168 168 _first_src_addr = NULL;
169 169 assert(!is_valid(), "sanity");
170 170 }
171 171
172 172 #ifdef ASSERT
173 173 void SplitInfo::verify_clear()
174 174 {
175 175 assert(_src_region_idx == 0, "not clear");
176 176 assert(_partial_obj_size == 0, "not clear");
177 177 assert(_destination == NULL, "not clear");
178 178 assert(_destination_count == 0, "not clear");
179 179 assert(_dest_region_addr == NULL, "not clear");
180 180 assert(_first_src_addr == NULL, "not clear");
181 181 }
182 182 #endif // #ifdef ASSERT
183 183
184 184
185 185 void PSParallelCompact::print_on_error(outputStream* st) {
186 186 _mark_bitmap.print_on_error(st);
187 187 }
188 188
189 189 #ifndef PRODUCT
190 190 const char* PSParallelCompact::space_names[] = {
191 191 "old ", "eden", "from", "to "
192 192 };
193 193
194 194 void PSParallelCompact::print_region_ranges()
195 195 {
196 196 tty->print_cr("space bottom top end new_top");
197 197 tty->print_cr("------ ---------- ---------- ---------- ----------");
198 198
199 199 for (unsigned int id = 0; id < last_space_id; ++id) {
200 200 const MutableSpace* space = _space_info[id].space();
201 201 tty->print_cr("%u %s "
202 202 SIZE_FORMAT_W(10) " " SIZE_FORMAT_W(10) " "
203 203 SIZE_FORMAT_W(10) " " SIZE_FORMAT_W(10) " ",
204 204 id, space_names[id],
205 205 summary_data().addr_to_region_idx(space->bottom()),
206 206 summary_data().addr_to_region_idx(space->top()),
207 207 summary_data().addr_to_region_idx(space->end()),
208 208 summary_data().addr_to_region_idx(_space_info[id].new_top()));
209 209 }
210 210 }
211 211
212 212 void
213 213 print_generic_summary_region(size_t i, const ParallelCompactData::RegionData* c)
214 214 {
215 215 #define REGION_IDX_FORMAT SIZE_FORMAT_W(7)
216 216 #define REGION_DATA_FORMAT SIZE_FORMAT_W(5)
217 217
218 218 ParallelCompactData& sd = PSParallelCompact::summary_data();
219 219 size_t dci = c->destination() ? sd.addr_to_region_idx(c->destination()) : 0;
220 220 tty->print_cr(REGION_IDX_FORMAT " " PTR_FORMAT " "
221 221 REGION_IDX_FORMAT " " PTR_FORMAT " "
222 222 REGION_DATA_FORMAT " " REGION_DATA_FORMAT " "
223 223 REGION_DATA_FORMAT " " REGION_IDX_FORMAT " %d",
224 224 i, c->data_location(), dci, c->destination(),
225 225 c->partial_obj_size(), c->live_obj_size(),
226 226 c->data_size(), c->source_region(), c->destination_count());
227 227
228 228 #undef REGION_IDX_FORMAT
229 229 #undef REGION_DATA_FORMAT
230 230 }
231 231
232 232 void
233 233 print_generic_summary_data(ParallelCompactData& summary_data,
234 234 HeapWord* const beg_addr,
235 235 HeapWord* const end_addr)
236 236 {
237 237 size_t total_words = 0;
238 238 size_t i = summary_data.addr_to_region_idx(beg_addr);
239 239 const size_t last = summary_data.addr_to_region_idx(end_addr);
240 240 HeapWord* pdest = 0;
241 241
242 242 while (i <= last) {
243 243 ParallelCompactData::RegionData* c = summary_data.region(i);
244 244 if (c->data_size() != 0 || c->destination() != pdest) {
245 245 print_generic_summary_region(i, c);
246 246 total_words += c->data_size();
247 247 pdest = c->destination();
248 248 }
249 249 ++i;
250 250 }
251 251
252 252 tty->print_cr("summary_data_bytes=" SIZE_FORMAT, total_words * HeapWordSize);
253 253 }
254 254
255 255 void
256 256 print_generic_summary_data(ParallelCompactData& summary_data,
257 257 SpaceInfo* space_info)
258 258 {
259 259 for (unsigned int id = 0; id < PSParallelCompact::last_space_id; ++id) {
260 260 const MutableSpace* space = space_info[id].space();
261 261 print_generic_summary_data(summary_data, space->bottom(),
262 262 MAX2(space->top(), space_info[id].new_top()));
263 263 }
264 264 }
265 265
266 266 void
267 267 print_initial_summary_region(size_t i,
268 268 const ParallelCompactData::RegionData* c,
269 269 bool newline = true)
270 270 {
271 271 tty->print(SIZE_FORMAT_W(5) " " PTR_FORMAT " "
272 272 SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " "
273 273 SIZE_FORMAT_W(5) " " SIZE_FORMAT_W(5) " %d",
274 274 i, c->destination(),
275 275 c->partial_obj_size(), c->live_obj_size(),
276 276 c->data_size(), c->source_region(), c->destination_count());
277 277 if (newline) tty->cr();
278 278 }
279 279
280 280 void
281 281 print_initial_summary_data(ParallelCompactData& summary_data,
282 282 const MutableSpace* space) {
283 283 if (space->top() == space->bottom()) {
284 284 return;
285 285 }
286 286
287 287 const size_t region_size = ParallelCompactData::RegionSize;
288 288 typedef ParallelCompactData::RegionData RegionData;
289 289 HeapWord* const top_aligned_up = summary_data.region_align_up(space->top());
290 290 const size_t end_region = summary_data.addr_to_region_idx(top_aligned_up);
291 291 const RegionData* c = summary_data.region(end_region - 1);
292 292 HeapWord* end_addr = c->destination() + c->data_size();
293 293 const size_t live_in_space = pointer_delta(end_addr, space->bottom());
294 294
295 295 // Print (and count) the full regions at the beginning of the space.
296 296 size_t full_region_count = 0;
297 297 size_t i = summary_data.addr_to_region_idx(space->bottom());
298 298 while (i < end_region && summary_data.region(i)->data_size() == region_size) {
299 299 print_initial_summary_region(i, summary_data.region(i));
300 300 ++full_region_count;
301 301 ++i;
302 302 }
303 303
304 304 size_t live_to_right = live_in_space - full_region_count * region_size;
305 305
306 306 double max_reclaimed_ratio = 0.0;
307 307 size_t max_reclaimed_ratio_region = 0;
308 308 size_t max_dead_to_right = 0;
309 309 size_t max_live_to_right = 0;
310 310
311 311 // Print the 'reclaimed ratio' for regions while there is something live in
312 312 // the region or to the right of it. The remaining regions are empty (and
313 313 // uninteresting), and computing the ratio will result in division by 0.
314 314 while (i < end_region && live_to_right > 0) {
315 315 c = summary_data.region(i);
316 316 HeapWord* const region_addr = summary_data.region_to_addr(i);
317 317 const size_t used_to_right = pointer_delta(space->top(), region_addr);
318 318 const size_t dead_to_right = used_to_right - live_to_right;
319 319 const double reclaimed_ratio = double(dead_to_right) / live_to_right;
320 320
321 321 if (reclaimed_ratio > max_reclaimed_ratio) {
322 322 max_reclaimed_ratio = reclaimed_ratio;
323 323 max_reclaimed_ratio_region = i;
324 324 max_dead_to_right = dead_to_right;
325 325 max_live_to_right = live_to_right;
326 326 }
327 327
328 328 print_initial_summary_region(i, c, false);
329 329 tty->print_cr(" %12.10f " SIZE_FORMAT_W(10) " " SIZE_FORMAT_W(10),
330 330 reclaimed_ratio, dead_to_right, live_to_right);
331 331
332 332 live_to_right -= c->data_size();
333 333 ++i;
334 334 }
335 335
336 336 // Any remaining regions are empty. Print one more if there is one.
337 337 if (i < end_region) {
338 338 print_initial_summary_region(i, summary_data.region(i));
339 339 }
340 340
341 341 tty->print_cr("max: " SIZE_FORMAT_W(4) " d2r=" SIZE_FORMAT_W(10) " "
342 342 "l2r=" SIZE_FORMAT_W(10) " max_ratio=%14.12f",
343 343 max_reclaimed_ratio_region, max_dead_to_right,
344 344 max_live_to_right, max_reclaimed_ratio);
345 345 }
346 346
347 347 void
348 348 print_initial_summary_data(ParallelCompactData& summary_data,
349 349 SpaceInfo* space_info) {
350 350 unsigned int id = PSParallelCompact::old_space_id;
351 351 const MutableSpace* space;
352 352 do {
353 353 space = space_info[id].space();
354 354 print_initial_summary_data(summary_data, space);
355 355 } while (++id < PSParallelCompact::eden_space_id);
356 356
357 357 do {
358 358 space = space_info[id].space();
359 359 print_generic_summary_data(summary_data, space->bottom(), space->top());
360 360 } while (++id < PSParallelCompact::last_space_id);
361 361 }
362 362 #endif // #ifndef PRODUCT
363 363
364 364 #ifdef ASSERT
365 365 size_t add_obj_count;
366 366 size_t add_obj_size;
367 367 size_t mark_bitmap_count;
368 368 size_t mark_bitmap_size;
369 369 #endif // #ifdef ASSERT
370 370
371 371 ParallelCompactData::ParallelCompactData()
372 372 {
373 373 _region_start = 0;
374 374
375 375 _region_vspace = 0;
376 376 _reserved_byte_size = 0;
377 377 _region_data = 0;
378 378 _region_count = 0;
379 379
380 380 _block_vspace = 0;
381 381 _block_data = 0;
382 382 _block_count = 0;
383 383 }
384 384
385 385 bool ParallelCompactData::initialize(MemRegion covered_region)
386 386 {
387 387 _region_start = covered_region.start();
388 388 const size_t region_size = covered_region.word_size();
389 389 DEBUG_ONLY(_region_end = _region_start + region_size;)
390 390
391 391 assert(region_align_down(_region_start) == _region_start,
392 392 "region start not aligned");
393 393 assert((region_size & RegionSizeOffsetMask) == 0,
394 394 "region size not a multiple of RegionSize");
395 395
396 396 bool result = initialize_region_data(region_size) && initialize_block_data();
397 397 return result;
398 398 }
399 399
400 400 PSVirtualSpace*
401 401 ParallelCompactData::create_vspace(size_t count, size_t element_size)
402 402 {
403 403 const size_t raw_bytes = count * element_size;
404 404 const size_t page_sz = os::page_size_for_region(raw_bytes, raw_bytes, 10);
405 405 const size_t granularity = os::vm_allocation_granularity();
406 406 _reserved_byte_size = align_size_up(raw_bytes, MAX2(page_sz, granularity));
407 407
408 408 const size_t rs_align = page_sz == (size_t) os::vm_page_size() ? 0 :
409 409 MAX2(page_sz, granularity);
410 410 ReservedSpace rs(_reserved_byte_size, rs_align, rs_align > 0);
411 411 os::trace_page_sizes("par compact", raw_bytes, raw_bytes, page_sz, rs.base(),
412 412 rs.size());
413 413
414 414 MemTracker::record_virtual_memory_type((address)rs.base(), mtGC);
415 415
416 416 PSVirtualSpace* vspace = new PSVirtualSpace(rs, page_sz);
417 417 if (vspace != 0) {
418 418 if (vspace->expand_by(_reserved_byte_size)) {
419 419 return vspace;
420 420 }
421 421 delete vspace;
422 422 // Release memory reserved in the space.
423 423 rs.release();
424 424 }
425 425
426 426 return 0;
427 427 }
428 428
429 429 bool ParallelCompactData::initialize_region_data(size_t region_size)
430 430 {
431 431 const size_t count = (region_size + RegionSizeOffsetMask) >> Log2RegionSize;
432 432 _region_vspace = create_vspace(count, sizeof(RegionData));
433 433 if (_region_vspace != 0) {
434 434 _region_data = (RegionData*)_region_vspace->reserved_low_addr();
435 435 _region_count = count;
436 436 return true;
437 437 }
438 438 return false;
439 439 }
440 440
441 441 bool ParallelCompactData::initialize_block_data()
442 442 {
443 443 assert(_region_count != 0, "region data must be initialized first");
444 444 const size_t count = _region_count << Log2BlocksPerRegion;
445 445 _block_vspace = create_vspace(count, sizeof(BlockData));
446 446 if (_block_vspace != 0) {
447 447 _block_data = (BlockData*)_block_vspace->reserved_low_addr();
448 448 _block_count = count;
449 449 return true;
450 450 }
451 451 return false;
452 452 }
453 453
454 454 void ParallelCompactData::clear()
455 455 {
456 456 memset(_region_data, 0, _region_vspace->committed_size());
457 457 memset(_block_data, 0, _block_vspace->committed_size());
458 458 }
459 459
460 460 void ParallelCompactData::clear_range(size_t beg_region, size_t end_region) {
461 461 assert(beg_region <= _region_count, "beg_region out of range");
462 462 assert(end_region <= _region_count, "end_region out of range");
463 463 assert(RegionSize % BlockSize == 0, "RegionSize not a multiple of BlockSize");
464 464
465 465 const size_t region_cnt = end_region - beg_region;
466 466 memset(_region_data + beg_region, 0, region_cnt * sizeof(RegionData));
467 467
468 468 const size_t beg_block = beg_region * BlocksPerRegion;
469 469 const size_t block_cnt = region_cnt * BlocksPerRegion;
470 470 memset(_block_data + beg_block, 0, block_cnt * sizeof(BlockData));
471 471 }
472 472
473 473 HeapWord* ParallelCompactData::partial_obj_end(size_t region_idx) const
474 474 {
475 475 const RegionData* cur_cp = region(region_idx);
476 476 const RegionData* const end_cp = region(region_count() - 1);
477 477
478 478 HeapWord* result = region_to_addr(region_idx);
479 479 if (cur_cp < end_cp) {
480 480 do {
481 481 result += cur_cp->partial_obj_size();
482 482 } while (cur_cp->partial_obj_size() == RegionSize && ++cur_cp < end_cp);
483 483 }
484 484 return result;
485 485 }
486 486
487 487 void ParallelCompactData::add_obj(HeapWord* addr, size_t len)
488 488 {
489 489 const size_t obj_ofs = pointer_delta(addr, _region_start);
490 490 const size_t beg_region = obj_ofs >> Log2RegionSize;
491 491 const size_t end_region = (obj_ofs + len - 1) >> Log2RegionSize;
492 492
493 493 DEBUG_ONLY(Atomic::inc_ptr(&add_obj_count);)
494 494 DEBUG_ONLY(Atomic::add_ptr(len, &add_obj_size);)
495 495
496 496 if (beg_region == end_region) {
497 497 // All in one region.
498 498 _region_data[beg_region].add_live_obj(len);
499 499 return;
500 500 }
501 501
502 502 // First region.
503 503 const size_t beg_ofs = region_offset(addr);
504 504 _region_data[beg_region].add_live_obj(RegionSize - beg_ofs);
505 505
506 506 Klass* klass = ((oop)addr)->klass();
507 507 // Middle regions--completely spanned by this object.
508 508 for (size_t region = beg_region + 1; region < end_region; ++region) {
509 509 _region_data[region].set_partial_obj_size(RegionSize);
510 510 _region_data[region].set_partial_obj_addr(addr);
511 511 }
512 512
513 513 // Last region.
514 514 const size_t end_ofs = region_offset(addr + len - 1);
515 515 _region_data[end_region].set_partial_obj_size(end_ofs + 1);
516 516 _region_data[end_region].set_partial_obj_addr(addr);
517 517 }
518 518
519 519 void
520 520 ParallelCompactData::summarize_dense_prefix(HeapWord* beg, HeapWord* end)
521 521 {
522 522 assert(region_offset(beg) == 0, "not RegionSize aligned");
523 523 assert(region_offset(end) == 0, "not RegionSize aligned");
524 524
525 525 size_t cur_region = addr_to_region_idx(beg);
526 526 const size_t end_region = addr_to_region_idx(end);
527 527 HeapWord* addr = beg;
528 528 while (cur_region < end_region) {
529 529 _region_data[cur_region].set_destination(addr);
530 530 _region_data[cur_region].set_destination_count(0);
531 531 _region_data[cur_region].set_source_region(cur_region);
532 532 _region_data[cur_region].set_data_location(addr);
533 533
534 534 // Update live_obj_size so the region appears completely full.
535 535 size_t live_size = RegionSize - _region_data[cur_region].partial_obj_size();
536 536 _region_data[cur_region].set_live_obj_size(live_size);
537 537
538 538 ++cur_region;
539 539 addr += RegionSize;
540 540 }
541 541 }
542 542
543 543 // Find the point at which a space can be split and, if necessary, record the
544 544 // split point.
545 545 //
546 546 // If the current src region (which overflowed the destination space) doesn't
547 547 // have a partial object, the split point is at the beginning of the current src
548 548 // region (an "easy" split, no extra bookkeeping required).
549 549 //
550 550 // If the current src region has a partial object, the split point is in the
551 551 // region where that partial object starts (call it the split_region). If
552 552 // split_region has a partial object, then the split point is just after that
553 553 // partial object (a "hard" split where we have to record the split data and
554 554 // zero the partial_obj_size field). With a "hard" split, we know that the
555 555 // partial_obj ends within split_region because the partial object that caused
556 556 // the overflow starts in split_region. If split_region doesn't have a partial
557 557 // obj, then the split is at the beginning of split_region (another "easy"
558 558 // split).
559 559 HeapWord*
560 560 ParallelCompactData::summarize_split_space(size_t src_region,
561 561 SplitInfo& split_info,
562 562 HeapWord* destination,
563 563 HeapWord* target_end,
564 564 HeapWord** target_next)
565 565 {
566 566 assert(destination <= target_end, "sanity");
567 567 assert(destination + _region_data[src_region].data_size() > target_end,
568 568 "region should not fit into target space");
569 569 assert(is_region_aligned(target_end), "sanity");
570 570
571 571 size_t split_region = src_region;
572 572 HeapWord* split_destination = destination;
573 573 size_t partial_obj_size = _region_data[src_region].partial_obj_size();
574 574
575 575 if (destination + partial_obj_size > target_end) {
576 576 // The split point is just after the partial object (if any) in the
577 577 // src_region that contains the start of the object that overflowed the
578 578 // destination space.
579 579 //
580 580 // Find the start of the "overflow" object and set split_region to the
581 581 // region containing it.
582 582 HeapWord* const overflow_obj = _region_data[src_region].partial_obj_addr();
583 583 split_region = addr_to_region_idx(overflow_obj);
584 584
585 585 // Clear the source_region field of all destination regions whose first word
586 586 // came from data after the split point (a non-null source_region field
587 587 // implies a region must be filled).
588 588 //
589 589 // An alternative to the simple loop below: clear during post_compact(),
590 590 // which uses memcpy instead of individual stores, and is easy to
591 591 // parallelize. (The downside is that it clears the entire RegionData
592 592 // object as opposed to just one field.)
593 593 //
594 594 // post_compact() would have to clear the summary data up to the highest
595 595 // address that was written during the summary phase, which would be
596 596 //
597 597 // max(top, max(new_top, clear_top))
598 598 //
599 599 // where clear_top is a new field in SpaceInfo. Would have to set clear_top
600 600 // to target_end.
601 601 const RegionData* const sr = region(split_region);
602 602 const size_t beg_idx =
603 603 addr_to_region_idx(region_align_up(sr->destination() +
604 604 sr->partial_obj_size()));
605 605 const size_t end_idx = addr_to_region_idx(target_end);
606 606
607 607 if (TraceParallelOldGCSummaryPhase) {
608 608 gclog_or_tty->print_cr("split: clearing source_region field in ["
609 609 SIZE_FORMAT ", " SIZE_FORMAT ")",
610 610 beg_idx, end_idx);
611 611 }
612 612 for (size_t idx = beg_idx; idx < end_idx; ++idx) {
613 613 _region_data[idx].set_source_region(0);
614 614 }
615 615
616 616 // Set split_destination and partial_obj_size to reflect the split region.
617 617 split_destination = sr->destination();
618 618 partial_obj_size = sr->partial_obj_size();
619 619 }
620 620
621 621 // The split is recorded only if a partial object extends onto the region.
622 622 if (partial_obj_size != 0) {
623 623 _region_data[split_region].set_partial_obj_size(0);
624 624 split_info.record(split_region, partial_obj_size, split_destination);
625 625 }
626 626
627 627 // Setup the continuation addresses.
628 628 *target_next = split_destination + partial_obj_size;
629 629 HeapWord* const source_next = region_to_addr(split_region) + partial_obj_size;
630 630
631 631 if (TraceParallelOldGCSummaryPhase) {
632 632 const char * split_type = partial_obj_size == 0 ? "easy" : "hard";
633 633 gclog_or_tty->print_cr("%s split: src=" PTR_FORMAT " src_c=" SIZE_FORMAT
634 634 " pos=" SIZE_FORMAT,
635 635 split_type, source_next, split_region,
636 636 partial_obj_size);
637 637 gclog_or_tty->print_cr("%s split: dst=" PTR_FORMAT " dst_c=" SIZE_FORMAT
638 638 " tn=" PTR_FORMAT,
639 639 split_type, split_destination,
640 640 addr_to_region_idx(split_destination),
641 641 *target_next);
642 642
643 643 if (partial_obj_size != 0) {
644 644 HeapWord* const po_beg = split_info.destination();
645 645 HeapWord* const po_end = po_beg + split_info.partial_obj_size();
646 646 gclog_or_tty->print_cr("%s split: "
647 647 "po_beg=" PTR_FORMAT " " SIZE_FORMAT " "
648 648 "po_end=" PTR_FORMAT " " SIZE_FORMAT,
649 649 split_type,
650 650 po_beg, addr_to_region_idx(po_beg),
651 651 po_end, addr_to_region_idx(po_end));
652 652 }
653 653 }
654 654
655 655 return source_next;
656 656 }
657 657
658 658 bool ParallelCompactData::summarize(SplitInfo& split_info,
659 659 HeapWord* source_beg, HeapWord* source_end,
660 660 HeapWord** source_next,
661 661 HeapWord* target_beg, HeapWord* target_end,
662 662 HeapWord** target_next)
663 663 {
664 664 if (TraceParallelOldGCSummaryPhase) {
665 665 HeapWord* const source_next_val = source_next == NULL ? NULL : *source_next;
666 666 tty->print_cr("sb=" PTR_FORMAT " se=" PTR_FORMAT " sn=" PTR_FORMAT
667 667 "tb=" PTR_FORMAT " te=" PTR_FORMAT " tn=" PTR_FORMAT,
668 668 source_beg, source_end, source_next_val,
669 669 target_beg, target_end, *target_next);
670 670 }
671 671
672 672 size_t cur_region = addr_to_region_idx(source_beg);
673 673 const size_t end_region = addr_to_region_idx(region_align_up(source_end));
674 674
675 675 HeapWord *dest_addr = target_beg;
676 676 while (cur_region < end_region) {
677 677 // The destination must be set even if the region has no data.
678 678 _region_data[cur_region].set_destination(dest_addr);
679 679
680 680 size_t words = _region_data[cur_region].data_size();
681 681 if (words > 0) {
682 682 // If cur_region does not fit entirely into the target space, find a point
683 683 // at which the source space can be 'split' so that part is copied to the
684 684 // target space and the rest is copied elsewhere.
685 685 if (dest_addr + words > target_end) {
686 686 assert(source_next != NULL, "source_next is NULL when splitting");
687 687 *source_next = summarize_split_space(cur_region, split_info, dest_addr,
688 688 target_end, target_next);
689 689 return false;
690 690 }
691 691
692 692 // Compute the destination_count for cur_region, and if necessary, update
693 693 // source_region for a destination region. The source_region field is
694 694 // updated if cur_region is the first (left-most) region to be copied to a
695 695 // destination region.
696 696 //
697 697 // The destination_count calculation is a bit subtle. A region that has
698 698 // data that compacts into itself does not count itself as a destination.
699 699 // This maintains the invariant that a zero count means the region is
700 700 // available and can be claimed and then filled.
701 701 uint destination_count = 0;
702 702 if (split_info.is_split(cur_region)) {
703 703 // The current region has been split: the partial object will be copied
704 704 // to one destination space and the remaining data will be copied to
705 705 // another destination space. Adjust the initial destination_count and,
706 706 // if necessary, set the source_region field if the partial object will
707 707 // cross a destination region boundary.
708 708 destination_count = split_info.destination_count();
709 709 if (destination_count == 2) {
710 710 size_t dest_idx = addr_to_region_idx(split_info.dest_region_addr());
711 711 _region_data[dest_idx].set_source_region(cur_region);
712 712 }
713 713 }
714 714
715 715 HeapWord* const last_addr = dest_addr + words - 1;
716 716 const size_t dest_region_1 = addr_to_region_idx(dest_addr);
717 717 const size_t dest_region_2 = addr_to_region_idx(last_addr);
718 718
719 719 // Initially assume that the destination regions will be the same and
720 720 // adjust the value below if necessary. Under this assumption, if
721 721 // cur_region == dest_region_2, then cur_region will be compacted
722 722 // completely into itself.
723 723 destination_count += cur_region == dest_region_2 ? 0 : 1;
724 724 if (dest_region_1 != dest_region_2) {
725 725 // Destination regions differ; adjust destination_count.
726 726 destination_count += 1;
727 727 // Data from cur_region will be copied to the start of dest_region_2.
728 728 _region_data[dest_region_2].set_source_region(cur_region);
729 729 } else if (region_offset(dest_addr) == 0) {
730 730 // Data from cur_region will be copied to the start of the destination
731 731 // region.
732 732 _region_data[dest_region_1].set_source_region(cur_region);
733 733 }
734 734
735 735 _region_data[cur_region].set_destination_count(destination_count);
736 736 _region_data[cur_region].set_data_location(region_to_addr(cur_region));
737 737 dest_addr += words;
738 738 }
739 739
740 740 ++cur_region;
741 741 }
742 742
743 743 *target_next = dest_addr;
744 744 return true;
745 745 }
746 746
747 747 HeapWord* ParallelCompactData::calc_new_pointer(HeapWord* addr) {
748 748 assert(addr != NULL, "Should detect NULL oop earlier");
749 749 assert(PSParallelCompact::gc_heap()->is_in(addr), "not in heap");
750 750 assert(PSParallelCompact::mark_bitmap()->is_marked(addr), "not marked");
751 751
752 752 // Region covering the object.
753 753 RegionData* const region_ptr = addr_to_region_ptr(addr);
754 754 HeapWord* result = region_ptr->destination();
755 755
756 756 // If the entire Region is live, the new location is region->destination + the
757 757 // offset of the object within in the Region.
758 758
759 759 // Run some performance tests to determine if this special case pays off. It
760 760 // is worth it for pointers into the dense prefix. If the optimization to
761 761 // avoid pointer updates in regions that only point to the dense prefix is
762 762 // ever implemented, this should be revisited.
763 763 if (region_ptr->data_size() == RegionSize) {
764 764 result += region_offset(addr);
765 765 return result;
766 766 }
767 767
768 768 // Otherwise, the new location is region->destination + block offset + the
769 769 // number of live words in the Block that are (a) to the left of addr and (b)
770 770 // due to objects that start in the Block.
771 771
772 772 // Fill in the block table if necessary. This is unsynchronized, so multiple
773 773 // threads may fill the block table for a region (harmless, since it is
774 774 // idempotent).
775 775 if (!region_ptr->blocks_filled()) {
776 776 PSParallelCompact::fill_blocks(addr_to_region_idx(addr));
777 777 region_ptr->set_blocks_filled();
778 778 }
779 779
780 780 HeapWord* const search_start = block_align_down(addr);
781 781 const size_t block_offset = addr_to_block_ptr(addr)->offset();
782 782
783 783 const ParMarkBitMap* bitmap = PSParallelCompact::mark_bitmap();
784 784 const size_t live = bitmap->live_words_in_range(search_start, oop(addr));
785 785 result += block_offset + live;
786 786 DEBUG_ONLY(PSParallelCompact::check_new_location(addr, result));
787 787 return result;
788 788 }
789 789
790 790 #ifdef ASSERT
791 791 void ParallelCompactData::verify_clear(const PSVirtualSpace* vspace)
792 792 {
793 793 const size_t* const beg = (const size_t*)vspace->committed_low_addr();
794 794 const size_t* const end = (const size_t*)vspace->committed_high_addr();
795 795 for (const size_t* p = beg; p < end; ++p) {
796 796 assert(*p == 0, "not zero");
797 797 }
798 798 }
799 799
800 800 void ParallelCompactData::verify_clear()
801 801 {
802 802 verify_clear(_region_vspace);
803 803 verify_clear(_block_vspace);
804 804 }
805 805 #endif // #ifdef ASSERT
806 806
807 807 STWGCTimer PSParallelCompact::_gc_timer;
808 808 ParallelOldTracer PSParallelCompact::_gc_tracer;
809 809 elapsedTimer PSParallelCompact::_accumulated_time;
810 810 unsigned int PSParallelCompact::_total_invocations = 0;
811 811 unsigned int PSParallelCompact::_maximum_compaction_gc_num = 0;
812 812 jlong PSParallelCompact::_time_of_last_gc = 0;
813 813 CollectorCounters* PSParallelCompact::_counters = NULL;
814 814 ParMarkBitMap PSParallelCompact::_mark_bitmap;
815 815 ParallelCompactData PSParallelCompact::_summary_data;
816 816
817 817 PSParallelCompact::IsAliveClosure PSParallelCompact::_is_alive_closure;
818 818
819 819 bool PSParallelCompact::IsAliveClosure::do_object_b(oop p) { return mark_bitmap()->is_marked(p); }
820 820
821 821 void PSParallelCompact::KeepAliveClosure::do_oop(oop* p) { PSParallelCompact::KeepAliveClosure::do_oop_work(p); }
822 822 void PSParallelCompact::KeepAliveClosure::do_oop(narrowOop* p) { PSParallelCompact::KeepAliveClosure::do_oop_work(p); }
823 823
824 824 PSParallelCompact::AdjustPointerClosure PSParallelCompact::_adjust_pointer_closure;
825 825 PSParallelCompact::AdjustKlassClosure PSParallelCompact::_adjust_klass_closure;
826 826
827 827 void PSParallelCompact::AdjustPointerClosure::do_oop(oop* p) { adjust_pointer(p); }
828 828 void PSParallelCompact::AdjustPointerClosure::do_oop(narrowOop* p) { adjust_pointer(p); }
829 829
830 830 void PSParallelCompact::FollowStackClosure::do_void() { _compaction_manager->follow_marking_stacks(); }
831 831
832 832 void PSParallelCompact::MarkAndPushClosure::do_oop(oop* p) {
833 833 mark_and_push(_compaction_manager, p);
834 834 }
835 835 void PSParallelCompact::MarkAndPushClosure::do_oop(narrowOop* p) { mark_and_push(_compaction_manager, p); }
836 836
837 837 void PSParallelCompact::FollowKlassClosure::do_klass(Klass* klass) {
838 838 klass->oops_do(_mark_and_push_closure);
839 839 }
840 840 void PSParallelCompact::AdjustKlassClosure::do_klass(Klass* klass) {
841 841 klass->oops_do(&PSParallelCompact::_adjust_pointer_closure);
842 842 }
843 843
844 844 void PSParallelCompact::post_initialize() {
845 845 ParallelScavengeHeap* heap = gc_heap();
846 846 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
847 847
848 848 MemRegion mr = heap->reserved_region();
849 849 _ref_processor =
850 850 new ReferenceProcessor(mr, // span
851 851 ParallelRefProcEnabled && (ParallelGCThreads > 1), // mt processing
852 852 (int) ParallelGCThreads, // mt processing degree
853 853 true, // mt discovery
854 854 (int) ParallelGCThreads, // mt discovery degree
855 855 true, // atomic_discovery
856 856 &_is_alive_closure); // non-header is alive closure
857 857 _counters = new CollectorCounters("PSParallelCompact", 1);
858 858
859 859 // Initialize static fields in ParCompactionManager.
860 860 ParCompactionManager::initialize(mark_bitmap());
861 861 }
862 862
863 863 bool PSParallelCompact::initialize() {
864 864 ParallelScavengeHeap* heap = gc_heap();
865 865 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
866 866 MemRegion mr = heap->reserved_region();
867 867
868 868 // Was the old gen get allocated successfully?
869 869 if (!heap->old_gen()->is_allocated()) {
870 870 return false;
871 871 }
872 872
873 873 initialize_space_info();
874 874 initialize_dead_wood_limiter();
875 875
876 876 if (!_mark_bitmap.initialize(mr)) {
877 877 vm_shutdown_during_initialization(
878 878 err_msg("Unable to allocate " SIZE_FORMAT "KB bitmaps for parallel "
879 879 "garbage collection for the requested " SIZE_FORMAT "KB heap.",
880 880 _mark_bitmap.reserved_byte_size()/K, mr.byte_size()/K));
881 881 return false;
882 882 }
883 883
884 884 if (!_summary_data.initialize(mr)) {
885 885 vm_shutdown_during_initialization(
886 886 err_msg("Unable to allocate " SIZE_FORMAT "KB card tables for parallel "
887 887 "garbage collection for the requested " SIZE_FORMAT "KB heap.",
888 888 _summary_data.reserved_byte_size()/K, mr.byte_size()/K));
889 889 return false;
890 890 }
891 891
892 892 return true;
893 893 }
894 894
895 895 void PSParallelCompact::initialize_space_info()
896 896 {
897 897 memset(&_space_info, 0, sizeof(_space_info));
898 898
899 899 ParallelScavengeHeap* heap = gc_heap();
900 900 PSYoungGen* young_gen = heap->young_gen();
901 901
902 902 _space_info[old_space_id].set_space(heap->old_gen()->object_space());
903 903 _space_info[eden_space_id].set_space(young_gen->eden_space());
904 904 _space_info[from_space_id].set_space(young_gen->from_space());
905 905 _space_info[to_space_id].set_space(young_gen->to_space());
906 906
907 907 _space_info[old_space_id].set_start_array(heap->old_gen()->start_array());
908 908 }
909 909
910 910 void PSParallelCompact::initialize_dead_wood_limiter()
911 911 {
912 912 const size_t max = 100;
913 913 _dwl_mean = double(MIN2(ParallelOldDeadWoodLimiterMean, max)) / 100.0;
914 914 _dwl_std_dev = double(MIN2(ParallelOldDeadWoodLimiterStdDev, max)) / 100.0;
915 915 _dwl_first_term = 1.0 / (sqrt(2.0 * M_PI) * _dwl_std_dev);
916 916 DEBUG_ONLY(_dwl_initialized = true;)
917 917 _dwl_adjustment = normal_distribution(1.0);
918 918 }
919 919
920 920 // Simple class for storing info about the heap at the start of GC, to be used
921 921 // after GC for comparison/printing.
922 922 class PreGCValues {
923 923 public:
924 924 PreGCValues() { }
925 925 PreGCValues(ParallelScavengeHeap* heap) { fill(heap); }
926 926
927 927 void fill(ParallelScavengeHeap* heap) {
928 928 _heap_used = heap->used();
929 929 _young_gen_used = heap->young_gen()->used_in_bytes();
930 930 _old_gen_used = heap->old_gen()->used_in_bytes();
931 931 _metadata_used = MetaspaceAux::used_bytes();
932 932 };
933 933
934 934 size_t heap_used() const { return _heap_used; }
935 935 size_t young_gen_used() const { return _young_gen_used; }
936 936 size_t old_gen_used() const { return _old_gen_used; }
937 937 size_t metadata_used() const { return _metadata_used; }
938 938
939 939 private:
940 940 size_t _heap_used;
941 941 size_t _young_gen_used;
942 942 size_t _old_gen_used;
943 943 size_t _metadata_used;
944 944 };
945 945
946 946 void
947 947 PSParallelCompact::clear_data_covering_space(SpaceId id)
948 948 {
949 949 // At this point, top is the value before GC, new_top() is the value that will
950 950 // be set at the end of GC. The marking bitmap is cleared to top; nothing
951 951 // should be marked above top. The summary data is cleared to the larger of
952 952 // top & new_top.
953 953 MutableSpace* const space = _space_info[id].space();
954 954 HeapWord* const bot = space->bottom();
955 955 HeapWord* const top = space->top();
956 956 HeapWord* const max_top = MAX2(top, _space_info[id].new_top());
957 957
958 958 const idx_t beg_bit = _mark_bitmap.addr_to_bit(bot);
959 959 const idx_t end_bit = BitMap::word_align_up(_mark_bitmap.addr_to_bit(top));
960 960 _mark_bitmap.clear_range(beg_bit, end_bit);
961 961
962 962 const size_t beg_region = _summary_data.addr_to_region_idx(bot);
963 963 const size_t end_region =
964 964 _summary_data.addr_to_region_idx(_summary_data.region_align_up(max_top));
965 965 _summary_data.clear_range(beg_region, end_region);
966 966
967 967 // Clear the data used to 'split' regions.
968 968 SplitInfo& split_info = _space_info[id].split_info();
969 969 if (split_info.is_valid()) {
970 970 split_info.clear();
971 971 }
972 972 DEBUG_ONLY(split_info.verify_clear();)
973 973 }
974 974
975 975 void PSParallelCompact::pre_compact(PreGCValues* pre_gc_values)
976 976 {
977 977 // Update the from & to space pointers in space_info, since they are swapped
978 978 // at each young gen gc. Do the update unconditionally (even though a
979 979 // promotion failure does not swap spaces) because an unknown number of minor
980 980 // collections will have swapped the spaces an unknown number of times.
981 981 GCTraceTime tm("pre compact", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
982 982 ParallelScavengeHeap* heap = gc_heap();
983 983 _space_info[from_space_id].set_space(heap->young_gen()->from_space());
984 984 _space_info[to_space_id].set_space(heap->young_gen()->to_space());
985 985
986 986 pre_gc_values->fill(heap);
987 987
988 988 DEBUG_ONLY(add_obj_count = add_obj_size = 0;)
989 989 DEBUG_ONLY(mark_bitmap_count = mark_bitmap_size = 0;)
990 990
991 991 // Increment the invocation count
992 992 heap->increment_total_collections(true);
993 993
994 994 // We need to track unique mark sweep invocations as well.
995 995 _total_invocations++;
996 996
997 997 heap->print_heap_before_gc();
998 998 heap->trace_heap_before_gc(&_gc_tracer);
999 999
1000 1000 // Fill in TLABs
1001 1001 heap->accumulate_statistics_all_tlabs();
1002 1002 heap->ensure_parsability(true); // retire TLABs
1003 1003
1004 1004 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
1005 1005 HandleMark hm; // Discard invalid handles created during verification
1006 1006 Universe::verify(" VerifyBeforeGC:");
1007 1007 }
1008 1008
1009 1009 // Verify object start arrays
1010 1010 if (VerifyObjectStartArray &&
1011 1011 VerifyBeforeGC) {
1012 1012 heap->old_gen()->verify_object_start_array();
1013 1013 }
1014 1014
1015 1015 DEBUG_ONLY(mark_bitmap()->verify_clear();)
1016 1016 DEBUG_ONLY(summary_data().verify_clear();)
1017 1017
1018 1018 // Have worker threads release resources the next time they run a task.
1019 1019 gc_task_manager()->release_all_resources();
1020 1020 }
1021 1021
1022 1022 void PSParallelCompact::post_compact()
1023 1023 {
1024 1024 GCTraceTime tm("post compact", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
1025 1025
1026 1026 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
1027 1027 // Clear the marking bitmap, summary data and split info.
1028 1028 clear_data_covering_space(SpaceId(id));
1029 1029 // Update top(). Must be done after clearing the bitmap and summary data.
1030 1030 _space_info[id].publish_new_top();
1031 1031 }
1032 1032
1033 1033 MutableSpace* const eden_space = _space_info[eden_space_id].space();
1034 1034 MutableSpace* const from_space = _space_info[from_space_id].space();
1035 1035 MutableSpace* const to_space = _space_info[to_space_id].space();
1036 1036
1037 1037 ParallelScavengeHeap* heap = gc_heap();
1038 1038 bool eden_empty = eden_space->is_empty();
1039 1039 if (!eden_empty) {
1040 1040 eden_empty = absorb_live_data_from_eden(heap->size_policy(),
1041 1041 heap->young_gen(), heap->old_gen());
1042 1042 }
1043 1043
1044 1044 // Update heap occupancy information which is used as input to the soft ref
1045 1045 // clearing policy at the next gc.
1046 1046 Universe::update_heap_info_at_gc();
1047 1047
1048 1048 bool young_gen_empty = eden_empty && from_space->is_empty() &&
1049 1049 to_space->is_empty();
1050 1050
1051 1051 BarrierSet* bs = heap->barrier_set();
1052 1052 if (bs->is_a(BarrierSet::ModRef)) {
1053 1053 ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs;
1054 1054 MemRegion old_mr = heap->old_gen()->reserved();
1055 1055
1056 1056 if (young_gen_empty) {
1057 1057 modBS->clear(MemRegion(old_mr.start(), old_mr.end()));
1058 1058 } else {
1059 1059 modBS->invalidate(MemRegion(old_mr.start(), old_mr.end()));
1060 1060 }
1061 1061 }
1062 1062
1063 1063 // Delete metaspaces for unloaded class loaders and clean up loader_data graph
1064 1064 ClassLoaderDataGraph::purge();
1065 1065 MetaspaceAux::verify_metrics();
1066 1066
1067 1067 Threads::gc_epilogue();
1068 1068 CodeCache::gc_epilogue();
1069 1069 JvmtiExport::gc_epilogue();
1070 1070
1071 1071 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
1072 1072
1073 1073 ref_processor()->enqueue_discovered_references(NULL);
1074 1074
1075 1075 if (ZapUnusedHeapArea) {
1076 1076 heap->gen_mangle_unused_area();
1077 1077 }
1078 1078
1079 1079 // Update time of last GC
1080 1080 reset_millis_since_last_gc();
1081 1081 }
1082 1082
1083 1083 HeapWord*
1084 1084 PSParallelCompact::compute_dense_prefix_via_density(const SpaceId id,
1085 1085 bool maximum_compaction)
1086 1086 {
1087 1087 const size_t region_size = ParallelCompactData::RegionSize;
1088 1088 const ParallelCompactData& sd = summary_data();
1089 1089
1090 1090 const MutableSpace* const space = _space_info[id].space();
1091 1091 HeapWord* const top_aligned_up = sd.region_align_up(space->top());
1092 1092 const RegionData* const beg_cp = sd.addr_to_region_ptr(space->bottom());
1093 1093 const RegionData* const end_cp = sd.addr_to_region_ptr(top_aligned_up);
1094 1094
1095 1095 // Skip full regions at the beginning of the space--they are necessarily part
1096 1096 // of the dense prefix.
1097 1097 size_t full_count = 0;
1098 1098 const RegionData* cp;
1099 1099 for (cp = beg_cp; cp < end_cp && cp->data_size() == region_size; ++cp) {
1100 1100 ++full_count;
1101 1101 }
1102 1102
1103 1103 assert(total_invocations() >= _maximum_compaction_gc_num, "sanity");
1104 1104 const size_t gcs_since_max = total_invocations() - _maximum_compaction_gc_num;
1105 1105 const bool interval_ended = gcs_since_max > HeapMaximumCompactionInterval;
1106 1106 if (maximum_compaction || cp == end_cp || interval_ended) {
1107 1107 _maximum_compaction_gc_num = total_invocations();
1108 1108 return sd.region_to_addr(cp);
1109 1109 }
1110 1110
1111 1111 HeapWord* const new_top = _space_info[id].new_top();
1112 1112 const size_t space_live = pointer_delta(new_top, space->bottom());
1113 1113 const size_t space_used = space->used_in_words();
1114 1114 const size_t space_capacity = space->capacity_in_words();
1115 1115
1116 1116 const double cur_density = double(space_live) / space_capacity;
1117 1117 const double deadwood_density =
1118 1118 (1.0 - cur_density) * (1.0 - cur_density) * cur_density * cur_density;
1119 1119 const size_t deadwood_goal = size_t(space_capacity * deadwood_density);
1120 1120
1121 1121 if (TraceParallelOldGCDensePrefix) {
1122 1122 tty->print_cr("cur_dens=%5.3f dw_dens=%5.3f dw_goal=" SIZE_FORMAT,
1123 1123 cur_density, deadwood_density, deadwood_goal);
1124 1124 tty->print_cr("space_live=" SIZE_FORMAT " " "space_used=" SIZE_FORMAT " "
1125 1125 "space_cap=" SIZE_FORMAT,
1126 1126 space_live, space_used,
1127 1127 space_capacity);
1128 1128 }
1129 1129
1130 1130 // XXX - Use binary search?
1131 1131 HeapWord* dense_prefix = sd.region_to_addr(cp);
1132 1132 const RegionData* full_cp = cp;
1133 1133 const RegionData* const top_cp = sd.addr_to_region_ptr(space->top() - 1);
1134 1134 while (cp < end_cp) {
1135 1135 HeapWord* region_destination = cp->destination();
1136 1136 const size_t cur_deadwood = pointer_delta(dense_prefix, region_destination);
1137 1137 if (TraceParallelOldGCDensePrefix && Verbose) {
1138 1138 tty->print_cr("c#=" SIZE_FORMAT_W(4) " dst=" PTR_FORMAT " "
1139 1139 "dp=" SIZE_FORMAT_W(8) " " "cdw=" SIZE_FORMAT_W(8),
1140 1140 sd.region(cp), region_destination,
1141 1141 dense_prefix, cur_deadwood);
1142 1142 }
1143 1143
1144 1144 if (cur_deadwood >= deadwood_goal) {
1145 1145 // Found the region that has the correct amount of deadwood to the left.
1146 1146 // This typically occurs after crossing a fairly sparse set of regions, so
1147 1147 // iterate backwards over those sparse regions, looking for the region
1148 1148 // that has the lowest density of live objects 'to the right.'
1149 1149 size_t space_to_left = sd.region(cp) * region_size;
1150 1150 size_t live_to_left = space_to_left - cur_deadwood;
1151 1151 size_t space_to_right = space_capacity - space_to_left;
1152 1152 size_t live_to_right = space_live - live_to_left;
1153 1153 double density_to_right = double(live_to_right) / space_to_right;
1154 1154 while (cp > full_cp) {
1155 1155 --cp;
1156 1156 const size_t prev_region_live_to_right = live_to_right -
1157 1157 cp->data_size();
1158 1158 const size_t prev_region_space_to_right = space_to_right + region_size;
1159 1159 double prev_region_density_to_right =
1160 1160 double(prev_region_live_to_right) / prev_region_space_to_right;
1161 1161 if (density_to_right <= prev_region_density_to_right) {
1162 1162 return dense_prefix;
1163 1163 }
1164 1164 if (TraceParallelOldGCDensePrefix && Verbose) {
1165 1165 tty->print_cr("backing up from c=" SIZE_FORMAT_W(4) " d2r=%10.8f "
1166 1166 "pc_d2r=%10.8f", sd.region(cp), density_to_right,
1167 1167 prev_region_density_to_right);
1168 1168 }
1169 1169 dense_prefix -= region_size;
1170 1170 live_to_right = prev_region_live_to_right;
1171 1171 space_to_right = prev_region_space_to_right;
1172 1172 density_to_right = prev_region_density_to_right;
1173 1173 }
1174 1174 return dense_prefix;
1175 1175 }
1176 1176
1177 1177 dense_prefix += region_size;
1178 1178 ++cp;
1179 1179 }
1180 1180
1181 1181 return dense_prefix;
1182 1182 }
1183 1183
1184 1184 #ifndef PRODUCT
1185 1185 void PSParallelCompact::print_dense_prefix_stats(const char* const algorithm,
1186 1186 const SpaceId id,
1187 1187 const bool maximum_compaction,
1188 1188 HeapWord* const addr)
1189 1189 {
1190 1190 const size_t region_idx = summary_data().addr_to_region_idx(addr);
1191 1191 RegionData* const cp = summary_data().region(region_idx);
1192 1192 const MutableSpace* const space = _space_info[id].space();
1193 1193 HeapWord* const new_top = _space_info[id].new_top();
1194 1194
1195 1195 const size_t space_live = pointer_delta(new_top, space->bottom());
1196 1196 const size_t dead_to_left = pointer_delta(addr, cp->destination());
1197 1197 const size_t space_cap = space->capacity_in_words();
1198 1198 const double dead_to_left_pct = double(dead_to_left) / space_cap;
1199 1199 const size_t live_to_right = new_top - cp->destination();
1200 1200 const size_t dead_to_right = space->top() - addr - live_to_right;
1201 1201
1202 1202 tty->print_cr("%s=" PTR_FORMAT " dpc=" SIZE_FORMAT_W(5) " "
1203 1203 "spl=" SIZE_FORMAT " "
1204 1204 "d2l=" SIZE_FORMAT " d2l%%=%6.4f "
1205 1205 "d2r=" SIZE_FORMAT " l2r=" SIZE_FORMAT
1206 1206 " ratio=%10.8f",
1207 1207 algorithm, addr, region_idx,
1208 1208 space_live,
1209 1209 dead_to_left, dead_to_left_pct,
1210 1210 dead_to_right, live_to_right,
1211 1211 double(dead_to_right) / live_to_right);
1212 1212 }
1213 1213 #endif // #ifndef PRODUCT
1214 1214
1215 1215 // Return a fraction indicating how much of the generation can be treated as
1216 1216 // "dead wood" (i.e., not reclaimed). The function uses a normal distribution
1217 1217 // based on the density of live objects in the generation to determine a limit,
1218 1218 // which is then adjusted so the return value is min_percent when the density is
1219 1219 // 1.
1220 1220 //
1221 1221 // The following table shows some return values for a different values of the
1222 1222 // standard deviation (ParallelOldDeadWoodLimiterStdDev); the mean is 0.5 and
1223 1223 // min_percent is 1.
1224 1224 //
1225 1225 // fraction allowed as dead wood
1226 1226 // -----------------------------------------------------------------
1227 1227 // density std_dev=70 std_dev=75 std_dev=80 std_dev=85 std_dev=90 std_dev=95
1228 1228 // ------- ---------- ---------- ---------- ---------- ---------- ----------
1229 1229 // 0.00000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000
1230 1230 // 0.05000 0.03193096 0.02836880 0.02550828 0.02319280 0.02130337 0.01974941
1231 1231 // 0.10000 0.05247504 0.04547452 0.03988045 0.03537016 0.03170171 0.02869272
1232 1232 // 0.15000 0.07135702 0.06111390 0.05296419 0.04641639 0.04110601 0.03676066
1233 1233 // 0.20000 0.08831616 0.07509618 0.06461766 0.05622444 0.04943437 0.04388975
1234 1234 // 0.25000 0.10311208 0.08724696 0.07471205 0.06469760 0.05661313 0.05002313
1235 1235 // 0.30000 0.11553050 0.09741183 0.08313394 0.07175114 0.06257797 0.05511132
1236 1236 // 0.35000 0.12538832 0.10545958 0.08978741 0.07731366 0.06727491 0.05911289
1237 1237 // 0.40000 0.13253818 0.11128511 0.09459590 0.08132834 0.07066107 0.06199500
1238 1238 // 0.45000 0.13687208 0.11481163 0.09750361 0.08375387 0.07270534 0.06373386
1239 1239 // 0.50000 0.13832410 0.11599237 0.09847664 0.08456518 0.07338887 0.06431510
1240 1240 // 0.55000 0.13687208 0.11481163 0.09750361 0.08375387 0.07270534 0.06373386
1241 1241 // 0.60000 0.13253818 0.11128511 0.09459590 0.08132834 0.07066107 0.06199500
1242 1242 // 0.65000 0.12538832 0.10545958 0.08978741 0.07731366 0.06727491 0.05911289
1243 1243 // 0.70000 0.11553050 0.09741183 0.08313394 0.07175114 0.06257797 0.05511132
1244 1244 // 0.75000 0.10311208 0.08724696 0.07471205 0.06469760 0.05661313 0.05002313
1245 1245 // 0.80000 0.08831616 0.07509618 0.06461766 0.05622444 0.04943437 0.04388975
1246 1246 // 0.85000 0.07135702 0.06111390 0.05296419 0.04641639 0.04110601 0.03676066
1247 1247 // 0.90000 0.05247504 0.04547452 0.03988045 0.03537016 0.03170171 0.02869272
1248 1248 // 0.95000 0.03193096 0.02836880 0.02550828 0.02319280 0.02130337 0.01974941
1249 1249 // 1.00000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000 0.01000000
1250 1250
1251 1251 double PSParallelCompact::dead_wood_limiter(double density, size_t min_percent)
1252 1252 {
1253 1253 assert(_dwl_initialized, "uninitialized");
1254 1254
1255 1255 // The raw limit is the value of the normal distribution at x = density.
1256 1256 const double raw_limit = normal_distribution(density);
1257 1257
1258 1258 // Adjust the raw limit so it becomes the minimum when the density is 1.
1259 1259 //
1260 1260 // First subtract the adjustment value (which is simply the precomputed value
1261 1261 // normal_distribution(1.0)); this yields a value of 0 when the density is 1.
1262 1262 // Then add the minimum value, so the minimum is returned when the density is
1263 1263 // 1. Finally, prevent negative values, which occur when the mean is not 0.5.
1264 1264 const double min = double(min_percent) / 100.0;
1265 1265 const double limit = raw_limit - _dwl_adjustment + min;
1266 1266 return MAX2(limit, 0.0);
1267 1267 }
1268 1268
1269 1269 ParallelCompactData::RegionData*
1270 1270 PSParallelCompact::first_dead_space_region(const RegionData* beg,
1271 1271 const RegionData* end)
1272 1272 {
1273 1273 const size_t region_size = ParallelCompactData::RegionSize;
1274 1274 ParallelCompactData& sd = summary_data();
1275 1275 size_t left = sd.region(beg);
1276 1276 size_t right = end > beg ? sd.region(end) - 1 : left;
1277 1277
1278 1278 // Binary search.
1279 1279 while (left < right) {
1280 1280 // Equivalent to (left + right) / 2, but does not overflow.
1281 1281 const size_t middle = left + (right - left) / 2;
1282 1282 RegionData* const middle_ptr = sd.region(middle);
1283 1283 HeapWord* const dest = middle_ptr->destination();
1284 1284 HeapWord* const addr = sd.region_to_addr(middle);
1285 1285 assert(dest != NULL, "sanity");
1286 1286 assert(dest <= addr, "must move left");
1287 1287
1288 1288 if (middle > left && dest < addr) {
1289 1289 right = middle - 1;
1290 1290 } else if (middle < right && middle_ptr->data_size() == region_size) {
1291 1291 left = middle + 1;
1292 1292 } else {
1293 1293 return middle_ptr;
1294 1294 }
1295 1295 }
1296 1296 return sd.region(left);
1297 1297 }
1298 1298
1299 1299 ParallelCompactData::RegionData*
1300 1300 PSParallelCompact::dead_wood_limit_region(const RegionData* beg,
1301 1301 const RegionData* end,
1302 1302 size_t dead_words)
1303 1303 {
1304 1304 ParallelCompactData& sd = summary_data();
1305 1305 size_t left = sd.region(beg);
1306 1306 size_t right = end > beg ? sd.region(end) - 1 : left;
1307 1307
1308 1308 // Binary search.
1309 1309 while (left < right) {
1310 1310 // Equivalent to (left + right) / 2, but does not overflow.
1311 1311 const size_t middle = left + (right - left) / 2;
1312 1312 RegionData* const middle_ptr = sd.region(middle);
1313 1313 HeapWord* const dest = middle_ptr->destination();
1314 1314 HeapWord* const addr = sd.region_to_addr(middle);
1315 1315 assert(dest != NULL, "sanity");
1316 1316 assert(dest <= addr, "must move left");
1317 1317
1318 1318 const size_t dead_to_left = pointer_delta(addr, dest);
1319 1319 if (middle > left && dead_to_left > dead_words) {
1320 1320 right = middle - 1;
1321 1321 } else if (middle < right && dead_to_left < dead_words) {
1322 1322 left = middle + 1;
1323 1323 } else {
1324 1324 return middle_ptr;
1325 1325 }
1326 1326 }
1327 1327 return sd.region(left);
1328 1328 }
1329 1329
1330 1330 // The result is valid during the summary phase, after the initial summarization
1331 1331 // of each space into itself, and before final summarization.
1332 1332 inline double
1333 1333 PSParallelCompact::reclaimed_ratio(const RegionData* const cp,
1334 1334 HeapWord* const bottom,
1335 1335 HeapWord* const top,
1336 1336 HeapWord* const new_top)
1337 1337 {
1338 1338 ParallelCompactData& sd = summary_data();
1339 1339
1340 1340 assert(cp != NULL, "sanity");
1341 1341 assert(bottom != NULL, "sanity");
1342 1342 assert(top != NULL, "sanity");
1343 1343 assert(new_top != NULL, "sanity");
1344 1344 assert(top >= new_top, "summary data problem?");
1345 1345 assert(new_top > bottom, "space is empty; should not be here");
1346 1346 assert(new_top >= cp->destination(), "sanity");
1347 1347 assert(top >= sd.region_to_addr(cp), "sanity");
1348 1348
1349 1349 HeapWord* const destination = cp->destination();
1350 1350 const size_t dense_prefix_live = pointer_delta(destination, bottom);
1351 1351 const size_t compacted_region_live = pointer_delta(new_top, destination);
1352 1352 const size_t compacted_region_used = pointer_delta(top,
1353 1353 sd.region_to_addr(cp));
1354 1354 const size_t reclaimable = compacted_region_used - compacted_region_live;
1355 1355
1356 1356 const double divisor = dense_prefix_live + 1.25 * compacted_region_live;
1357 1357 return double(reclaimable) / divisor;
1358 1358 }
1359 1359
1360 1360 // Return the address of the end of the dense prefix, a.k.a. the start of the
1361 1361 // compacted region. The address is always on a region boundary.
1362 1362 //
1363 1363 // Completely full regions at the left are skipped, since no compaction can
1364 1364 // occur in those regions. Then the maximum amount of dead wood to allow is
1365 1365 // computed, based on the density (amount live / capacity) of the generation;
1366 1366 // the region with approximately that amount of dead space to the left is
1367 1367 // identified as the limit region. Regions between the last completely full
1368 1368 // region and the limit region are scanned and the one that has the best
1369 1369 // (maximum) reclaimed_ratio() is selected.
1370 1370 HeapWord*
1371 1371 PSParallelCompact::compute_dense_prefix(const SpaceId id,
1372 1372 bool maximum_compaction)
1373 1373 {
1374 1374 if (ParallelOldGCSplitALot) {
1375 1375 if (_space_info[id].dense_prefix() != _space_info[id].space()->bottom()) {
1376 1376 // The value was chosen to provoke splitting a young gen space; use it.
1377 1377 return _space_info[id].dense_prefix();
1378 1378 }
1379 1379 }
1380 1380
1381 1381 const size_t region_size = ParallelCompactData::RegionSize;
1382 1382 const ParallelCompactData& sd = summary_data();
1383 1383
1384 1384 const MutableSpace* const space = _space_info[id].space();
1385 1385 HeapWord* const top = space->top();
1386 1386 HeapWord* const top_aligned_up = sd.region_align_up(top);
1387 1387 HeapWord* const new_top = _space_info[id].new_top();
1388 1388 HeapWord* const new_top_aligned_up = sd.region_align_up(new_top);
1389 1389 HeapWord* const bottom = space->bottom();
1390 1390 const RegionData* const beg_cp = sd.addr_to_region_ptr(bottom);
1391 1391 const RegionData* const top_cp = sd.addr_to_region_ptr(top_aligned_up);
1392 1392 const RegionData* const new_top_cp =
1393 1393 sd.addr_to_region_ptr(new_top_aligned_up);
1394 1394
1395 1395 // Skip full regions at the beginning of the space--they are necessarily part
1396 1396 // of the dense prefix.
1397 1397 const RegionData* const full_cp = first_dead_space_region(beg_cp, new_top_cp);
1398 1398 assert(full_cp->destination() == sd.region_to_addr(full_cp) ||
1399 1399 space->is_empty(), "no dead space allowed to the left");
1400 1400 assert(full_cp->data_size() < region_size || full_cp == new_top_cp - 1,
1401 1401 "region must have dead space");
1402 1402
1403 1403 // The gc number is saved whenever a maximum compaction is done, and used to
1404 1404 // determine when the maximum compaction interval has expired. This avoids
1405 1405 // successive max compactions for different reasons.
1406 1406 assert(total_invocations() >= _maximum_compaction_gc_num, "sanity");
1407 1407 const size_t gcs_since_max = total_invocations() - _maximum_compaction_gc_num;
1408 1408 const bool interval_ended = gcs_since_max > HeapMaximumCompactionInterval ||
1409 1409 total_invocations() == HeapFirstMaximumCompactionCount;
1410 1410 if (maximum_compaction || full_cp == top_cp || interval_ended) {
1411 1411 _maximum_compaction_gc_num = total_invocations();
1412 1412 return sd.region_to_addr(full_cp);
1413 1413 }
1414 1414
1415 1415 const size_t space_live = pointer_delta(new_top, bottom);
1416 1416 const size_t space_used = space->used_in_words();
1417 1417 const size_t space_capacity = space->capacity_in_words();
1418 1418
1419 1419 const double density = double(space_live) / double(space_capacity);
1420 1420 const size_t min_percent_free = MarkSweepDeadRatio;
1421 1421 const double limiter = dead_wood_limiter(density, min_percent_free);
1422 1422 const size_t dead_wood_max = space_used - space_live;
1423 1423 const size_t dead_wood_limit = MIN2(size_t(space_capacity * limiter),
1424 1424 dead_wood_max);
1425 1425
1426 1426 if (TraceParallelOldGCDensePrefix) {
1427 1427 tty->print_cr("space_live=" SIZE_FORMAT " " "space_used=" SIZE_FORMAT " "
1428 1428 "space_cap=" SIZE_FORMAT,
1429 1429 space_live, space_used,
1430 1430 space_capacity);
1431 1431 tty->print_cr("dead_wood_limiter(%6.4f, %d)=%6.4f "
1432 1432 "dead_wood_max=" SIZE_FORMAT " dead_wood_limit=" SIZE_FORMAT,
1433 1433 density, min_percent_free, limiter,
1434 1434 dead_wood_max, dead_wood_limit);
1435 1435 }
1436 1436
1437 1437 // Locate the region with the desired amount of dead space to the left.
1438 1438 const RegionData* const limit_cp =
1439 1439 dead_wood_limit_region(full_cp, top_cp, dead_wood_limit);
1440 1440
1441 1441 // Scan from the first region with dead space to the limit region and find the
1442 1442 // one with the best (largest) reclaimed ratio.
1443 1443 double best_ratio = 0.0;
1444 1444 const RegionData* best_cp = full_cp;
1445 1445 for (const RegionData* cp = full_cp; cp < limit_cp; ++cp) {
1446 1446 double tmp_ratio = reclaimed_ratio(cp, bottom, top, new_top);
1447 1447 if (tmp_ratio > best_ratio) {
1448 1448 best_cp = cp;
1449 1449 best_ratio = tmp_ratio;
1450 1450 }
1451 1451 }
1452 1452
1453 1453 #if 0
1454 1454 // Something to consider: if the region with the best ratio is 'close to' the
1455 1455 // first region w/free space, choose the first region with free space
1456 1456 // ("first-free"). The first-free region is usually near the start of the
1457 1457 // heap, which means we are copying most of the heap already, so copy a bit
1458 1458 // more to get complete compaction.
1459 1459 if (pointer_delta(best_cp, full_cp, sizeof(RegionData)) < 4) {
1460 1460 _maximum_compaction_gc_num = total_invocations();
1461 1461 best_cp = full_cp;
1462 1462 }
1463 1463 #endif // #if 0
1464 1464
1465 1465 return sd.region_to_addr(best_cp);
1466 1466 }
1467 1467
1468 1468 #ifndef PRODUCT
1469 1469 void
1470 1470 PSParallelCompact::fill_with_live_objects(SpaceId id, HeapWord* const start,
1471 1471 size_t words)
1472 1472 {
1473 1473 if (TraceParallelOldGCSummaryPhase) {
1474 1474 tty->print_cr("fill_with_live_objects [" PTR_FORMAT " " PTR_FORMAT ") "
1475 1475 SIZE_FORMAT, start, start + words, words);
1476 1476 }
1477 1477
1478 1478 ObjectStartArray* const start_array = _space_info[id].start_array();
1479 1479 CollectedHeap::fill_with_objects(start, words);
1480 1480 for (HeapWord* p = start; p < start + words; p += oop(p)->size()) {
1481 1481 _mark_bitmap.mark_obj(p, words);
1482 1482 _summary_data.add_obj(p, words);
1483 1483 start_array->allocate_block(p);
1484 1484 }
1485 1485 }
1486 1486
1487 1487 void
1488 1488 PSParallelCompact::summarize_new_objects(SpaceId id, HeapWord* start)
1489 1489 {
1490 1490 ParallelCompactData& sd = summary_data();
1491 1491 MutableSpace* space = _space_info[id].space();
1492 1492
1493 1493 // Find the source and destination start addresses.
1494 1494 HeapWord* const src_addr = sd.region_align_down(start);
1495 1495 HeapWord* dst_addr;
1496 1496 if (src_addr < start) {
1497 1497 dst_addr = sd.addr_to_region_ptr(src_addr)->destination();
1498 1498 } else if (src_addr > space->bottom()) {
1499 1499 // The start (the original top() value) is aligned to a region boundary so
1500 1500 // the associated region does not have a destination. Compute the
1501 1501 // destination from the previous region.
1502 1502 RegionData* const cp = sd.addr_to_region_ptr(src_addr) - 1;
1503 1503 dst_addr = cp->destination() + cp->data_size();
1504 1504 } else {
1505 1505 // Filling the entire space.
1506 1506 dst_addr = space->bottom();
1507 1507 }
1508 1508 assert(dst_addr != NULL, "sanity");
1509 1509
1510 1510 // Update the summary data.
1511 1511 bool result = _summary_data.summarize(_space_info[id].split_info(),
1512 1512 src_addr, space->top(), NULL,
1513 1513 dst_addr, space->end(),
1514 1514 _space_info[id].new_top_addr());
1515 1515 assert(result, "should not fail: bad filler object size");
1516 1516 }
1517 1517
1518 1518 void
1519 1519 PSParallelCompact::provoke_split_fill_survivor(SpaceId id)
1520 1520 {
1521 1521 if (total_invocations() % (ParallelOldGCSplitInterval * 3) != 0) {
1522 1522 return;
1523 1523 }
1524 1524
1525 1525 MutableSpace* const space = _space_info[id].space();
1526 1526 if (space->is_empty()) {
1527 1527 HeapWord* b = space->bottom();
1528 1528 HeapWord* t = b + space->capacity_in_words() / 2;
1529 1529 space->set_top(t);
1530 1530 if (ZapUnusedHeapArea) {
1531 1531 space->set_top_for_allocations();
1532 1532 }
1533 1533
1534 1534 size_t min_size = CollectedHeap::min_fill_size();
1535 1535 size_t obj_len = min_size;
1536 1536 while (b + obj_len <= t) {
1537 1537 CollectedHeap::fill_with_object(b, obj_len);
1538 1538 mark_bitmap()->mark_obj(b, obj_len);
1539 1539 summary_data().add_obj(b, obj_len);
1540 1540 b += obj_len;
1541 1541 obj_len = (obj_len & (min_size*3)) + min_size; // 8 16 24 32 8 16 24 32 ...
1542 1542 }
1543 1543 if (b < t) {
1544 1544 // The loop didn't completely fill to t (top); adjust top downward.
1545 1545 space->set_top(b);
1546 1546 if (ZapUnusedHeapArea) {
1547 1547 space->set_top_for_allocations();
1548 1548 }
1549 1549 }
1550 1550
1551 1551 HeapWord** nta = _space_info[id].new_top_addr();
1552 1552 bool result = summary_data().summarize(_space_info[id].split_info(),
1553 1553 space->bottom(), space->top(), NULL,
1554 1554 space->bottom(), space->end(), nta);
1555 1555 assert(result, "space must fit into itself");
1556 1556 }
1557 1557 }
1558 1558
1559 1559 void
1560 1560 PSParallelCompact::provoke_split(bool & max_compaction)
1561 1561 {
1562 1562 if (total_invocations() % ParallelOldGCSplitInterval != 0) {
1563 1563 return;
1564 1564 }
1565 1565
1566 1566 const size_t region_size = ParallelCompactData::RegionSize;
1567 1567 ParallelCompactData& sd = summary_data();
1568 1568
1569 1569 MutableSpace* const eden_space = _space_info[eden_space_id].space();
1570 1570 MutableSpace* const from_space = _space_info[from_space_id].space();
1571 1571 const size_t eden_live = pointer_delta(eden_space->top(),
1572 1572 _space_info[eden_space_id].new_top());
1573 1573 const size_t from_live = pointer_delta(from_space->top(),
1574 1574 _space_info[from_space_id].new_top());
1575 1575
1576 1576 const size_t min_fill_size = CollectedHeap::min_fill_size();
1577 1577 const size_t eden_free = pointer_delta(eden_space->end(), eden_space->top());
1578 1578 const size_t eden_fillable = eden_free >= min_fill_size ? eden_free : 0;
1579 1579 const size_t from_free = pointer_delta(from_space->end(), from_space->top());
1580 1580 const size_t from_fillable = from_free >= min_fill_size ? from_free : 0;
1581 1581
1582 1582 // Choose the space to split; need at least 2 regions live (or fillable).
1583 1583 SpaceId id;
1584 1584 MutableSpace* space;
1585 1585 size_t live_words;
1586 1586 size_t fill_words;
1587 1587 if (eden_live + eden_fillable >= region_size * 2) {
1588 1588 id = eden_space_id;
1589 1589 space = eden_space;
1590 1590 live_words = eden_live;
1591 1591 fill_words = eden_fillable;
1592 1592 } else if (from_live + from_fillable >= region_size * 2) {
1593 1593 id = from_space_id;
1594 1594 space = from_space;
1595 1595 live_words = from_live;
1596 1596 fill_words = from_fillable;
1597 1597 } else {
1598 1598 return; // Give up.
1599 1599 }
1600 1600 assert(fill_words == 0 || fill_words >= min_fill_size, "sanity");
1601 1601
1602 1602 if (live_words < region_size * 2) {
1603 1603 // Fill from top() to end() w/live objects of mixed sizes.
1604 1604 HeapWord* const fill_start = space->top();
1605 1605 live_words += fill_words;
1606 1606
1607 1607 space->set_top(fill_start + fill_words);
1608 1608 if (ZapUnusedHeapArea) {
1609 1609 space->set_top_for_allocations();
1610 1610 }
1611 1611
1612 1612 HeapWord* cur_addr = fill_start;
1613 1613 while (fill_words > 0) {
1614 1614 const size_t r = (size_t)os::random() % (region_size / 2) + min_fill_size;
1615 1615 size_t cur_size = MIN2(align_object_size_(r), fill_words);
1616 1616 if (fill_words - cur_size < min_fill_size) {
1617 1617 cur_size = fill_words; // Avoid leaving a fragment too small to fill.
1618 1618 }
1619 1619
1620 1620 CollectedHeap::fill_with_object(cur_addr, cur_size);
1621 1621 mark_bitmap()->mark_obj(cur_addr, cur_size);
1622 1622 sd.add_obj(cur_addr, cur_size);
1623 1623
1624 1624 cur_addr += cur_size;
1625 1625 fill_words -= cur_size;
1626 1626 }
1627 1627
1628 1628 summarize_new_objects(id, fill_start);
1629 1629 }
1630 1630
1631 1631 max_compaction = false;
1632 1632
1633 1633 // Manipulate the old gen so that it has room for about half of the live data
1634 1634 // in the target young gen space (live_words / 2).
1635 1635 id = old_space_id;
1636 1636 space = _space_info[id].space();
1637 1637 const size_t free_at_end = space->free_in_words();
1638 1638 const size_t free_target = align_object_size(live_words / 2);
1639 1639 const size_t dead = pointer_delta(space->top(), _space_info[id].new_top());
1640 1640
1641 1641 if (free_at_end >= free_target + min_fill_size) {
1642 1642 // Fill space above top() and set the dense prefix so everything survives.
1643 1643 HeapWord* const fill_start = space->top();
1644 1644 const size_t fill_size = free_at_end - free_target;
1645 1645 space->set_top(space->top() + fill_size);
1646 1646 if (ZapUnusedHeapArea) {
1647 1647 space->set_top_for_allocations();
1648 1648 }
1649 1649 fill_with_live_objects(id, fill_start, fill_size);
1650 1650 summarize_new_objects(id, fill_start);
1651 1651 _space_info[id].set_dense_prefix(sd.region_align_down(space->top()));
1652 1652 } else if (dead + free_at_end > free_target) {
1653 1653 // Find a dense prefix that makes the right amount of space available.
1654 1654 HeapWord* cur = sd.region_align_down(space->top());
1655 1655 HeapWord* cur_destination = sd.addr_to_region_ptr(cur)->destination();
1656 1656 size_t dead_to_right = pointer_delta(space->end(), cur_destination);
1657 1657 while (dead_to_right < free_target) {
1658 1658 cur -= region_size;
1659 1659 cur_destination = sd.addr_to_region_ptr(cur)->destination();
1660 1660 dead_to_right = pointer_delta(space->end(), cur_destination);
1661 1661 }
1662 1662 _space_info[id].set_dense_prefix(cur);
1663 1663 }
1664 1664 }
1665 1665 #endif // #ifndef PRODUCT
1666 1666
1667 1667 void PSParallelCompact::summarize_spaces_quick()
1668 1668 {
1669 1669 for (unsigned int i = 0; i < last_space_id; ++i) {
1670 1670 const MutableSpace* space = _space_info[i].space();
1671 1671 HeapWord** nta = _space_info[i].new_top_addr();
1672 1672 bool result = _summary_data.summarize(_space_info[i].split_info(),
1673 1673 space->bottom(), space->top(), NULL,
1674 1674 space->bottom(), space->end(), nta);
1675 1675 assert(result, "space must fit into itself");
1676 1676 _space_info[i].set_dense_prefix(space->bottom());
1677 1677 }
1678 1678
1679 1679 #ifndef PRODUCT
1680 1680 if (ParallelOldGCSplitALot) {
1681 1681 provoke_split_fill_survivor(to_space_id);
1682 1682 }
1683 1683 #endif // #ifndef PRODUCT
1684 1684 }
1685 1685
1686 1686 void PSParallelCompact::fill_dense_prefix_end(SpaceId id)
1687 1687 {
1688 1688 HeapWord* const dense_prefix_end = dense_prefix(id);
1689 1689 const RegionData* region = _summary_data.addr_to_region_ptr(dense_prefix_end);
1690 1690 const idx_t dense_prefix_bit = _mark_bitmap.addr_to_bit(dense_prefix_end);
1691 1691 if (dead_space_crosses_boundary(region, dense_prefix_bit)) {
1692 1692 // Only enough dead space is filled so that any remaining dead space to the
1693 1693 // left is larger than the minimum filler object. (The remainder is filled
1694 1694 // during the copy/update phase.)
1695 1695 //
1696 1696 // The size of the dead space to the right of the boundary is not a
1697 1697 // concern, since compaction will be able to use whatever space is
1698 1698 // available.
1699 1699 //
1700 1700 // Here '||' is the boundary, 'x' represents a don't care bit and a box
1701 1701 // surrounds the space to be filled with an object.
1702 1702 //
1703 1703 // In the 32-bit VM, each bit represents two 32-bit words:
1704 1704 // +---+
1705 1705 // a) beg_bits: ... x x x | 0 | || 0 x x ...
1706 1706 // end_bits: ... x x x | 0 | || 0 x x ...
1707 1707 // +---+
1708 1708 //
1709 1709 // In the 64-bit VM, each bit represents one 64-bit word:
1710 1710 // +------------+
1711 1711 // b) beg_bits: ... x x x | 0 || 0 | x x ...
1712 1712 // end_bits: ... x x 1 | 0 || 0 | x x ...
1713 1713 // +------------+
1714 1714 // +-------+
1715 1715 // c) beg_bits: ... x x | 0 0 | || 0 x x ...
1716 1716 // end_bits: ... x 1 | 0 0 | || 0 x x ...
1717 1717 // +-------+
1718 1718 // +-----------+
1719 1719 // d) beg_bits: ... x | 0 0 0 | || 0 x x ...
1720 1720 // end_bits: ... 1 | 0 0 0 | || 0 x x ...
1721 1721 // +-----------+
1722 1722 // +-------+
1723 1723 // e) beg_bits: ... 0 0 | 0 0 | || 0 x x ...
1724 1724 // end_bits: ... 0 0 | 0 0 | || 0 x x ...
1725 1725 // +-------+
1726 1726
1727 1727 // Initially assume case a, c or e will apply.
1728 1728 size_t obj_len = CollectedHeap::min_fill_size();
1729 1729 HeapWord* obj_beg = dense_prefix_end - obj_len;
1730 1730
1731 1731 #ifdef _LP64
1732 1732 if (MinObjAlignment > 1) { // object alignment > heap word size
1733 1733 // Cases a, c or e.
1734 1734 } else if (_mark_bitmap.is_obj_end(dense_prefix_bit - 2)) {
1735 1735 // Case b above.
1736 1736 obj_beg = dense_prefix_end - 1;
1737 1737 } else if (!_mark_bitmap.is_obj_end(dense_prefix_bit - 3) &&
1738 1738 _mark_bitmap.is_obj_end(dense_prefix_bit - 4)) {
1739 1739 // Case d above.
1740 1740 obj_beg = dense_prefix_end - 3;
1741 1741 obj_len = 3;
1742 1742 }
1743 1743 #endif // #ifdef _LP64
1744 1744
1745 1745 CollectedHeap::fill_with_object(obj_beg, obj_len);
1746 1746 _mark_bitmap.mark_obj(obj_beg, obj_len);
1747 1747 _summary_data.add_obj(obj_beg, obj_len);
1748 1748 assert(start_array(id) != NULL, "sanity");
1749 1749 start_array(id)->allocate_block(obj_beg);
1750 1750 }
1751 1751 }
1752 1752
1753 1753 void
1754 1754 PSParallelCompact::clear_source_region(HeapWord* beg_addr, HeapWord* end_addr)
1755 1755 {
1756 1756 RegionData* const beg_ptr = _summary_data.addr_to_region_ptr(beg_addr);
1757 1757 HeapWord* const end_aligned_up = _summary_data.region_align_up(end_addr);
1758 1758 RegionData* const end_ptr = _summary_data.addr_to_region_ptr(end_aligned_up);
1759 1759 for (RegionData* cur = beg_ptr; cur < end_ptr; ++cur) {
1760 1760 cur->set_source_region(0);
1761 1761 }
1762 1762 }
1763 1763
1764 1764 void
1765 1765 PSParallelCompact::summarize_space(SpaceId id, bool maximum_compaction)
1766 1766 {
1767 1767 assert(id < last_space_id, "id out of range");
1768 1768 assert(_space_info[id].dense_prefix() == _space_info[id].space()->bottom() ||
1769 1769 ParallelOldGCSplitALot && id == old_space_id,
1770 1770 "should have been reset in summarize_spaces_quick()");
1771 1771
1772 1772 const MutableSpace* space = _space_info[id].space();
1773 1773 if (_space_info[id].new_top() != space->bottom()) {
1774 1774 HeapWord* dense_prefix_end = compute_dense_prefix(id, maximum_compaction);
1775 1775 _space_info[id].set_dense_prefix(dense_prefix_end);
1776 1776
1777 1777 #ifndef PRODUCT
1778 1778 if (TraceParallelOldGCDensePrefix) {
1779 1779 print_dense_prefix_stats("ratio", id, maximum_compaction,
1780 1780 dense_prefix_end);
1781 1781 HeapWord* addr = compute_dense_prefix_via_density(id, maximum_compaction);
1782 1782 print_dense_prefix_stats("density", id, maximum_compaction, addr);
1783 1783 }
1784 1784 #endif // #ifndef PRODUCT
1785 1785
1786 1786 // Recompute the summary data, taking into account the dense prefix. If
1787 1787 // every last byte will be reclaimed, then the existing summary data which
1788 1788 // compacts everything can be left in place.
1789 1789 if (!maximum_compaction && dense_prefix_end != space->bottom()) {
1790 1790 // If dead space crosses the dense prefix boundary, it is (at least
1791 1791 // partially) filled with a dummy object, marked live and added to the
1792 1792 // summary data. This simplifies the copy/update phase and must be done
1793 1793 // before the final locations of objects are determined, to prevent
1794 1794 // leaving a fragment of dead space that is too small to fill.
1795 1795 fill_dense_prefix_end(id);
1796 1796
1797 1797 // Compute the destination of each Region, and thus each object.
1798 1798 _summary_data.summarize_dense_prefix(space->bottom(), dense_prefix_end);
1799 1799 _summary_data.summarize(_space_info[id].split_info(),
1800 1800 dense_prefix_end, space->top(), NULL,
1801 1801 dense_prefix_end, space->end(),
1802 1802 _space_info[id].new_top_addr());
1803 1803 }
1804 1804 }
1805 1805
1806 1806 if (TraceParallelOldGCSummaryPhase) {
1807 1807 const size_t region_size = ParallelCompactData::RegionSize;
1808 1808 HeapWord* const dense_prefix_end = _space_info[id].dense_prefix();
1809 1809 const size_t dp_region = _summary_data.addr_to_region_idx(dense_prefix_end);
1810 1810 const size_t dp_words = pointer_delta(dense_prefix_end, space->bottom());
1811 1811 HeapWord* const new_top = _space_info[id].new_top();
1812 1812 const HeapWord* nt_aligned_up = _summary_data.region_align_up(new_top);
1813 1813 const size_t cr_words = pointer_delta(nt_aligned_up, dense_prefix_end);
1814 1814 tty->print_cr("id=%d cap=" SIZE_FORMAT " dp=" PTR_FORMAT " "
1815 1815 "dp_region=" SIZE_FORMAT " " "dp_count=" SIZE_FORMAT " "
1816 1816 "cr_count=" SIZE_FORMAT " " "nt=" PTR_FORMAT,
1817 1817 id, space->capacity_in_words(), dense_prefix_end,
1818 1818 dp_region, dp_words / region_size,
1819 1819 cr_words / region_size, new_top);
1820 1820 }
1821 1821 }
1822 1822
1823 1823 #ifndef PRODUCT
1824 1824 void PSParallelCompact::summary_phase_msg(SpaceId dst_space_id,
1825 1825 HeapWord* dst_beg, HeapWord* dst_end,
1826 1826 SpaceId src_space_id,
1827 1827 HeapWord* src_beg, HeapWord* src_end)
1828 1828 {
1829 1829 if (TraceParallelOldGCSummaryPhase) {
1830 1830 tty->print_cr("summarizing %d [%s] into %d [%s]: "
1831 1831 "src=" PTR_FORMAT "-" PTR_FORMAT " "
1832 1832 SIZE_FORMAT "-" SIZE_FORMAT " "
1833 1833 "dst=" PTR_FORMAT "-" PTR_FORMAT " "
1834 1834 SIZE_FORMAT "-" SIZE_FORMAT,
1835 1835 src_space_id, space_names[src_space_id],
1836 1836 dst_space_id, space_names[dst_space_id],
1837 1837 src_beg, src_end,
1838 1838 _summary_data.addr_to_region_idx(src_beg),
1839 1839 _summary_data.addr_to_region_idx(src_end),
1840 1840 dst_beg, dst_end,
1841 1841 _summary_data.addr_to_region_idx(dst_beg),
1842 1842 _summary_data.addr_to_region_idx(dst_end));
1843 1843 }
1844 1844 }
1845 1845 #endif // #ifndef PRODUCT
1846 1846
1847 1847 void PSParallelCompact::summary_phase(ParCompactionManager* cm,
1848 1848 bool maximum_compaction)
1849 1849 {
1850 1850 GCTraceTime tm("summary phase", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
1851 1851 // trace("2");
1852 1852
1853 1853 #ifdef ASSERT
1854 1854 if (TraceParallelOldGCMarkingPhase) {
1855 1855 tty->print_cr("add_obj_count=" SIZE_FORMAT " "
1856 1856 "add_obj_bytes=" SIZE_FORMAT,
1857 1857 add_obj_count, add_obj_size * HeapWordSize);
1858 1858 tty->print_cr("mark_bitmap_count=" SIZE_FORMAT " "
1859 1859 "mark_bitmap_bytes=" SIZE_FORMAT,
1860 1860 mark_bitmap_count, mark_bitmap_size * HeapWordSize);
1861 1861 }
1862 1862 #endif // #ifdef ASSERT
1863 1863
1864 1864 // Quick summarization of each space into itself, to see how much is live.
1865 1865 summarize_spaces_quick();
1866 1866
1867 1867 if (TraceParallelOldGCSummaryPhase) {
1868 1868 tty->print_cr("summary_phase: after summarizing each space to self");
1869 1869 Universe::print();
1870 1870 NOT_PRODUCT(print_region_ranges());
1871 1871 if (Verbose) {
1872 1872 NOT_PRODUCT(print_initial_summary_data(_summary_data, _space_info));
1873 1873 }
1874 1874 }
1875 1875
1876 1876 // The amount of live data that will end up in old space (assuming it fits).
1877 1877 size_t old_space_total_live = 0;
1878 1878 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
1879 1879 old_space_total_live += pointer_delta(_space_info[id].new_top(),
1880 1880 _space_info[id].space()->bottom());
1881 1881 }
1882 1882
1883 1883 MutableSpace* const old_space = _space_info[old_space_id].space();
1884 1884 const size_t old_capacity = old_space->capacity_in_words();
1885 1885 if (old_space_total_live > old_capacity) {
1886 1886 // XXX - should also try to expand
1887 1887 maximum_compaction = true;
1888 1888 }
1889 1889 #ifndef PRODUCT
1890 1890 if (ParallelOldGCSplitALot && old_space_total_live < old_capacity) {
1891 1891 provoke_split(maximum_compaction);
1892 1892 }
1893 1893 #endif // #ifndef PRODUCT
1894 1894
1895 1895 // Old generations.
1896 1896 summarize_space(old_space_id, maximum_compaction);
1897 1897
1898 1898 // Summarize the remaining spaces in the young gen. The initial target space
1899 1899 // is the old gen. If a space does not fit entirely into the target, then the
1900 1900 // remainder is compacted into the space itself and that space becomes the new
1901 1901 // target.
1902 1902 SpaceId dst_space_id = old_space_id;
1903 1903 HeapWord* dst_space_end = old_space->end();
1904 1904 HeapWord** new_top_addr = _space_info[dst_space_id].new_top_addr();
1905 1905 for (unsigned int id = eden_space_id; id < last_space_id; ++id) {
1906 1906 const MutableSpace* space = _space_info[id].space();
1907 1907 const size_t live = pointer_delta(_space_info[id].new_top(),
1908 1908 space->bottom());
1909 1909 const size_t available = pointer_delta(dst_space_end, *new_top_addr);
1910 1910
1911 1911 NOT_PRODUCT(summary_phase_msg(dst_space_id, *new_top_addr, dst_space_end,
1912 1912 SpaceId(id), space->bottom(), space->top());)
1913 1913 if (live > 0 && live <= available) {
1914 1914 // All the live data will fit.
1915 1915 bool done = _summary_data.summarize(_space_info[id].split_info(),
1916 1916 space->bottom(), space->top(),
1917 1917 NULL,
1918 1918 *new_top_addr, dst_space_end,
1919 1919 new_top_addr);
1920 1920 assert(done, "space must fit into old gen");
1921 1921
1922 1922 // Reset the new_top value for the space.
1923 1923 _space_info[id].set_new_top(space->bottom());
1924 1924 } else if (live > 0) {
1925 1925 // Attempt to fit part of the source space into the target space.
1926 1926 HeapWord* next_src_addr = NULL;
1927 1927 bool done = _summary_data.summarize(_space_info[id].split_info(),
1928 1928 space->bottom(), space->top(),
1929 1929 &next_src_addr,
1930 1930 *new_top_addr, dst_space_end,
1931 1931 new_top_addr);
1932 1932 assert(!done, "space should not fit into old gen");
1933 1933 assert(next_src_addr != NULL, "sanity");
1934 1934
1935 1935 // The source space becomes the new target, so the remainder is compacted
1936 1936 // within the space itself.
1937 1937 dst_space_id = SpaceId(id);
1938 1938 dst_space_end = space->end();
1939 1939 new_top_addr = _space_info[id].new_top_addr();
1940 1940 NOT_PRODUCT(summary_phase_msg(dst_space_id,
1941 1941 space->bottom(), dst_space_end,
1942 1942 SpaceId(id), next_src_addr, space->top());)
1943 1943 done = _summary_data.summarize(_space_info[id].split_info(),
1944 1944 next_src_addr, space->top(),
1945 1945 NULL,
1946 1946 space->bottom(), dst_space_end,
1947 1947 new_top_addr);
1948 1948 assert(done, "space must fit when compacted into itself");
1949 1949 assert(*new_top_addr <= space->top(), "usage should not grow");
1950 1950 }
1951 1951 }
1952 1952
1953 1953 if (TraceParallelOldGCSummaryPhase) {
1954 1954 tty->print_cr("summary_phase: after final summarization");
1955 1955 Universe::print();
1956 1956 NOT_PRODUCT(print_region_ranges());
1957 1957 if (Verbose) {
1958 1958 NOT_PRODUCT(print_generic_summary_data(_summary_data, _space_info));
1959 1959 }
1960 1960 }
1961 1961 }
1962 1962
1963 1963 // This method should contain all heap-specific policy for invoking a full
1964 1964 // collection. invoke_no_policy() will only attempt to compact the heap; it
1965 1965 // will do nothing further. If we need to bail out for policy reasons, scavenge
1966 1966 // before full gc, or any other specialized behavior, it needs to be added here.
1967 1967 //
1968 1968 // Note that this method should only be called from the vm_thread while at a
1969 1969 // safepoint.
1970 1970 //
1971 1971 // Note that the all_soft_refs_clear flag in the collector policy
1972 1972 // may be true because this method can be called without intervening
1973 1973 // activity. For example when the heap space is tight and full measure
1974 1974 // are being taken to free space.
1975 1975 void PSParallelCompact::invoke(bool maximum_heap_compaction) {
1976 1976 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
1977 1977 assert(Thread::current() == (Thread*)VMThread::vm_thread(),
1978 1978 "should be in vm thread");
1979 1979
1980 1980 ParallelScavengeHeap* heap = gc_heap();
1981 1981 GCCause::Cause gc_cause = heap->gc_cause();
1982 1982 assert(!heap->is_gc_active(), "not reentrant");
1983 1983
1984 1984 PSAdaptiveSizePolicy* policy = heap->size_policy();
1985 1985 IsGCActiveMark mark;
1986 1986
1987 1987 if (ScavengeBeforeFullGC) {
1988 1988 PSScavenge::invoke_no_policy();
1989 1989 }
1990 1990
1991 1991 const bool clear_all_soft_refs =
1992 1992 heap->collector_policy()->should_clear_all_soft_refs();
1993 1993
1994 1994 PSParallelCompact::invoke_no_policy(clear_all_soft_refs ||
1995 1995 maximum_heap_compaction);
1996 1996 }
1997 1997
1998 1998 // This method contains no policy. You should probably
1999 1999 // be calling invoke() instead.
2000 2000 bool PSParallelCompact::invoke_no_policy(bool maximum_heap_compaction) {
2001 2001 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
2002 2002 assert(ref_processor() != NULL, "Sanity");
2003 2003
2004 2004 if (GC_locker::check_active_before_gc()) {
2005 2005 return false;
2006 2006 }
2007 2007
2008 2008 ParallelScavengeHeap* heap = gc_heap();
2009 2009
2010 2010 _gc_timer.register_gc_start();
2011 2011 _gc_tracer.report_gc_start(heap->gc_cause(), _gc_timer.gc_start());
2012 2012
2013 2013 TimeStamp marking_start;
2014 2014 TimeStamp compaction_start;
2015 2015 TimeStamp collection_exit;
2016 2016
2017 2017 GCCause::Cause gc_cause = heap->gc_cause();
2018 2018 PSYoungGen* young_gen = heap->young_gen();
2019 2019 PSOldGen* old_gen = heap->old_gen();
2020 2020 PSAdaptiveSizePolicy* size_policy = heap->size_policy();
2021 2021
2022 2022 // The scope of casr should end after code that can change
2023 2023 // CollectorPolicy::_should_clear_all_soft_refs.
2024 2024 ClearedAllSoftRefs casr(maximum_heap_compaction,
2025 2025 heap->collector_policy());
2026 2026
2027 2027 if (ZapUnusedHeapArea) {
2028 2028 // Save information needed to minimize mangling
2029 2029 heap->record_gen_tops_before_GC();
2030 2030 }
2031 2031
2032 2032 heap->pre_full_gc_dump(&_gc_timer);
2033 2033
2034 2034 _print_phases = PrintGCDetails && PrintParallelOldGCPhaseTimes;
2035 2035
2036 2036 // Make sure data structures are sane, make the heap parsable, and do other
2037 2037 // miscellaneous bookkeeping.
2038 2038 PreGCValues pre_gc_values;
2039 2039 pre_compact(&pre_gc_values);
2040 2040
2041 2041 // Get the compaction manager reserved for the VM thread.
2042 2042 ParCompactionManager* const vmthread_cm =
2043 2043 ParCompactionManager::manager_array(gc_task_manager()->workers());
2044 2044
2045 2045 // Place after pre_compact() where the number of invocations is incremented.
2046 2046 AdaptiveSizePolicyOutput(size_policy, heap->total_collections());
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2047 2047
2048 2048 {
2049 2049 ResourceMark rm;
2050 2050 HandleMark hm;
2051 2051
2052 2052 // Set the number of GC threads to be used in this collection
2053 2053 gc_task_manager()->set_active_gang();
2054 2054 gc_task_manager()->task_idle_workers();
2055 2055 heap->set_par_threads(gc_task_manager()->active_workers());
2056 2056
2057 - gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
2058 2057 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
2059 2058 GCTraceTime t1(GCCauseString("Full GC", gc_cause), PrintGC, !PrintGCDetails, NULL, _gc_tracer.gc_id());
2060 2059 TraceCollectorStats tcs(counters());
2061 2060 TraceMemoryManagerStats tms(true /* Full GC */,gc_cause);
2062 2061
2063 2062 if (TraceGen1Time) accumulated_time()->start();
2064 2063
2065 2064 // Let the size policy know we're starting
2066 2065 size_policy->major_collection_begin();
2067 2066
2068 2067 CodeCache::gc_prologue();
2069 2068 Threads::gc_prologue();
2070 2069
2071 2070 COMPILER2_PRESENT(DerivedPointerTable::clear());
2072 2071
2073 2072 ref_processor()->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
2074 2073 ref_processor()->setup_policy(maximum_heap_compaction);
2075 2074
2076 2075 bool marked_for_unloading = false;
2077 2076
2078 2077 marking_start.update();
2079 2078 marking_phase(vmthread_cm, maximum_heap_compaction, &_gc_tracer);
2080 2079
2081 2080 bool max_on_system_gc = UseMaximumCompactionOnSystemGC
2082 2081 && gc_cause == GCCause::_java_lang_system_gc;
2083 2082 summary_phase(vmthread_cm, maximum_heap_compaction || max_on_system_gc);
2084 2083
2085 2084 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity"));
2086 2085 COMPILER2_PRESENT(DerivedPointerTable::set_active(false));
2087 2086
2088 2087 // adjust_roots() updates Universe::_intArrayKlassObj which is
2089 2088 // needed by the compaction for filling holes in the dense prefix.
2090 2089 adjust_roots();
2091 2090
2092 2091 compaction_start.update();
2093 2092 compact();
2094 2093
2095 2094 // Reset the mark bitmap, summary data, and do other bookkeeping. Must be
2096 2095 // done before resizing.
2097 2096 post_compact();
2098 2097
2099 2098 // Let the size policy know we're done
2100 2099 size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause);
2101 2100
2102 2101 if (UseAdaptiveSizePolicy) {
2103 2102 if (PrintAdaptiveSizePolicy) {
2104 2103 gclog_or_tty->print("AdaptiveSizeStart: ");
2105 2104 gclog_or_tty->stamp();
2106 2105 gclog_or_tty->print_cr(" collection: %d ",
2107 2106 heap->total_collections());
2108 2107 if (Verbose) {
2109 2108 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d",
2110 2109 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes());
2111 2110 }
2112 2111 }
2113 2112
2114 2113 // Don't check if the size_policy is ready here. Let
2115 2114 // the size_policy check that internally.
2116 2115 if (UseAdaptiveGenerationSizePolicyAtMajorCollection &&
2117 2116 ((gc_cause != GCCause::_java_lang_system_gc) ||
2118 2117 UseAdaptiveSizePolicyWithSystemGC)) {
2119 2118 // Calculate optimal free space amounts
2120 2119 assert(young_gen->max_size() >
2121 2120 young_gen->from_space()->capacity_in_bytes() +
2122 2121 young_gen->to_space()->capacity_in_bytes(),
2123 2122 "Sizes of space in young gen are out-of-bounds");
2124 2123
2125 2124 size_t young_live = young_gen->used_in_bytes();
2126 2125 size_t eden_live = young_gen->eden_space()->used_in_bytes();
2127 2126 size_t old_live = old_gen->used_in_bytes();
2128 2127 size_t cur_eden = young_gen->eden_space()->capacity_in_bytes();
2129 2128 size_t max_old_gen_size = old_gen->max_gen_size();
2130 2129 size_t max_eden_size = young_gen->max_size() -
2131 2130 young_gen->from_space()->capacity_in_bytes() -
2132 2131 young_gen->to_space()->capacity_in_bytes();
2133 2132
2134 2133 // Used for diagnostics
2135 2134 size_policy->clear_generation_free_space_flags();
2136 2135
2137 2136 size_policy->compute_generations_free_space(young_live,
2138 2137 eden_live,
2139 2138 old_live,
2140 2139 cur_eden,
2141 2140 max_old_gen_size,
2142 2141 max_eden_size,
2143 2142 true /* full gc*/);
2144 2143
2145 2144 size_policy->check_gc_overhead_limit(young_live,
2146 2145 eden_live,
2147 2146 max_old_gen_size,
2148 2147 max_eden_size,
2149 2148 true /* full gc*/,
2150 2149 gc_cause,
2151 2150 heap->collector_policy());
2152 2151
2153 2152 size_policy->decay_supplemental_growth(true /* full gc*/);
2154 2153
2155 2154 heap->resize_old_gen(
2156 2155 size_policy->calculated_old_free_size_in_bytes());
2157 2156
2158 2157 // Don't resize the young generation at an major collection. A
2159 2158 // desired young generation size may have been calculated but
2160 2159 // resizing the young generation complicates the code because the
2161 2160 // resizing of the old generation may have moved the boundary
2162 2161 // between the young generation and the old generation. Let the
2163 2162 // young generation resizing happen at the minor collections.
2164 2163 }
2165 2164 if (PrintAdaptiveSizePolicy) {
2166 2165 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ",
2167 2166 heap->total_collections());
2168 2167 }
2169 2168 }
2170 2169
2171 2170 if (UsePerfData) {
2172 2171 PSGCAdaptivePolicyCounters* const counters = heap->gc_policy_counters();
2173 2172 counters->update_counters();
2174 2173 counters->update_old_capacity(old_gen->capacity_in_bytes());
2175 2174 counters->update_young_capacity(young_gen->capacity_in_bytes());
2176 2175 }
2177 2176
2178 2177 heap->resize_all_tlabs();
2179 2178
2180 2179 // Resize the metaspace capactiy after a collection
2181 2180 MetaspaceGC::compute_new_size();
2182 2181
2183 2182 if (TraceGen1Time) accumulated_time()->stop();
2184 2183
2185 2184 if (PrintGC) {
2186 2185 if (PrintGCDetails) {
2187 2186 // No GC timestamp here. This is after GC so it would be confusing.
2188 2187 young_gen->print_used_change(pre_gc_values.young_gen_used());
2189 2188 old_gen->print_used_change(pre_gc_values.old_gen_used());
2190 2189 heap->print_heap_change(pre_gc_values.heap_used());
2191 2190 MetaspaceAux::print_metaspace_change(pre_gc_values.metadata_used());
2192 2191 } else {
2193 2192 heap->print_heap_change(pre_gc_values.heap_used());
2194 2193 }
2195 2194 }
2196 2195
2197 2196 // Track memory usage and detect low memory
2198 2197 MemoryService::track_memory_usage();
2199 2198 heap->update_counters();
2200 2199 gc_task_manager()->release_idle_workers();
2201 2200 }
2202 2201
2203 2202 #ifdef ASSERT
2204 2203 for (size_t i = 0; i < ParallelGCThreads + 1; ++i) {
2205 2204 ParCompactionManager* const cm =
2206 2205 ParCompactionManager::manager_array(int(i));
2207 2206 assert(cm->marking_stack()->is_empty(), "should be empty");
2208 2207 assert(ParCompactionManager::region_list(int(i))->is_empty(), "should be empty");
2209 2208 }
2210 2209 #endif // ASSERT
2211 2210
2212 2211 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
2213 2212 HandleMark hm; // Discard invalid handles created during verification
2214 2213 Universe::verify(" VerifyAfterGC:");
2215 2214 }
2216 2215
2217 2216 // Re-verify object start arrays
2218 2217 if (VerifyObjectStartArray &&
2219 2218 VerifyAfterGC) {
2220 2219 old_gen->verify_object_start_array();
2221 2220 }
2222 2221
2223 2222 if (ZapUnusedHeapArea) {
2224 2223 old_gen->object_space()->check_mangled_unused_area_complete();
2225 2224 }
2226 2225
2227 2226 NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
2228 2227
2229 2228 collection_exit.update();
2230 2229
2231 2230 heap->print_heap_after_gc();
2232 2231 heap->trace_heap_after_gc(&_gc_tracer);
2233 2232
2234 2233 if (PrintGCTaskTimeStamps) {
2235 2234 gclog_or_tty->print_cr("VM-Thread " INT64_FORMAT " " INT64_FORMAT " "
2236 2235 INT64_FORMAT,
2237 2236 marking_start.ticks(), compaction_start.ticks(),
2238 2237 collection_exit.ticks());
2239 2238 gc_task_manager()->print_task_time_stamps();
2240 2239 }
2241 2240
2242 2241 heap->post_full_gc_dump(&_gc_timer);
2243 2242
2244 2243 #ifdef TRACESPINNING
2245 2244 ParallelTaskTerminator::print_termination_counts();
2246 2245 #endif
2247 2246
2248 2247 _gc_timer.register_gc_end();
2249 2248
2250 2249 _gc_tracer.report_dense_prefix(dense_prefix(old_space_id));
2251 2250 _gc_tracer.report_gc_end(_gc_timer.gc_end(), _gc_timer.time_partitions());
2252 2251
2253 2252 return true;
2254 2253 }
2255 2254
2256 2255 bool PSParallelCompact::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
2257 2256 PSYoungGen* young_gen,
2258 2257 PSOldGen* old_gen) {
2259 2258 MutableSpace* const eden_space = young_gen->eden_space();
2260 2259 assert(!eden_space->is_empty(), "eden must be non-empty");
2261 2260 assert(young_gen->virtual_space()->alignment() ==
2262 2261 old_gen->virtual_space()->alignment(), "alignments do not match");
2263 2262
2264 2263 if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) {
2265 2264 return false;
2266 2265 }
2267 2266
2268 2267 // Both generations must be completely committed.
2269 2268 if (young_gen->virtual_space()->uncommitted_size() != 0) {
2270 2269 return false;
2271 2270 }
2272 2271 if (old_gen->virtual_space()->uncommitted_size() != 0) {
2273 2272 return false;
2274 2273 }
2275 2274
2276 2275 // Figure out how much to take from eden. Include the average amount promoted
2277 2276 // in the total; otherwise the next young gen GC will simply bail out to a
2278 2277 // full GC.
2279 2278 const size_t alignment = old_gen->virtual_space()->alignment();
2280 2279 const size_t eden_used = eden_space->used_in_bytes();
2281 2280 const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average();
2282 2281 const size_t absorb_size = align_size_up(eden_used + promoted, alignment);
2283 2282 const size_t eden_capacity = eden_space->capacity_in_bytes();
2284 2283
2285 2284 if (absorb_size >= eden_capacity) {
2286 2285 return false; // Must leave some space in eden.
2287 2286 }
2288 2287
2289 2288 const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size;
2290 2289 if (new_young_size < young_gen->min_gen_size()) {
2291 2290 return false; // Respect young gen minimum size.
2292 2291 }
2293 2292
2294 2293 if (TraceAdaptiveGCBoundary && Verbose) {
2295 2294 gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: "
2296 2295 "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K "
2297 2296 "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K "
2298 2297 "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ",
2299 2298 absorb_size / K,
2300 2299 eden_capacity / K, (eden_capacity - absorb_size) / K,
2301 2300 young_gen->from_space()->used_in_bytes() / K,
2302 2301 young_gen->to_space()->used_in_bytes() / K,
2303 2302 young_gen->capacity_in_bytes() / K, new_young_size / K);
2304 2303 }
2305 2304
2306 2305 // Fill the unused part of the old gen.
2307 2306 MutableSpace* const old_space = old_gen->object_space();
2308 2307 HeapWord* const unused_start = old_space->top();
2309 2308 size_t const unused_words = pointer_delta(old_space->end(), unused_start);
2310 2309
2311 2310 if (unused_words > 0) {
2312 2311 if (unused_words < CollectedHeap::min_fill_size()) {
2313 2312 return false; // If the old gen cannot be filled, must give up.
2314 2313 }
2315 2314 CollectedHeap::fill_with_objects(unused_start, unused_words);
2316 2315 }
2317 2316
2318 2317 // Take the live data from eden and set both top and end in the old gen to
2319 2318 // eden top. (Need to set end because reset_after_change() mangles the region
2320 2319 // from end to virtual_space->high() in debug builds).
2321 2320 HeapWord* const new_top = eden_space->top();
2322 2321 old_gen->virtual_space()->expand_into(young_gen->virtual_space(),
2323 2322 absorb_size);
2324 2323 young_gen->reset_after_change();
2325 2324 old_space->set_top(new_top);
2326 2325 old_space->set_end(new_top);
2327 2326 old_gen->reset_after_change();
2328 2327
2329 2328 // Update the object start array for the filler object and the data from eden.
2330 2329 ObjectStartArray* const start_array = old_gen->start_array();
2331 2330 for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) {
2332 2331 start_array->allocate_block(p);
2333 2332 }
2334 2333
2335 2334 // Could update the promoted average here, but it is not typically updated at
2336 2335 // full GCs and the value to use is unclear. Something like
2337 2336 //
2338 2337 // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc.
2339 2338
2340 2339 size_policy->set_bytes_absorbed_from_eden(absorb_size);
2341 2340 return true;
2342 2341 }
2343 2342
2344 2343 GCTaskManager* const PSParallelCompact::gc_task_manager() {
2345 2344 assert(ParallelScavengeHeap::gc_task_manager() != NULL,
2346 2345 "shouldn't return NULL");
2347 2346 return ParallelScavengeHeap::gc_task_manager();
2348 2347 }
2349 2348
2350 2349 void PSParallelCompact::marking_phase(ParCompactionManager* cm,
2351 2350 bool maximum_heap_compaction,
2352 2351 ParallelOldTracer *gc_tracer) {
2353 2352 // Recursively traverse all live objects and mark them
2354 2353 GCTraceTime tm("marking phase", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2355 2354
2356 2355 ParallelScavengeHeap* heap = gc_heap();
2357 2356 uint parallel_gc_threads = heap->gc_task_manager()->workers();
2358 2357 uint active_gc_threads = heap->gc_task_manager()->active_workers();
2359 2358 TaskQueueSetSuper* qset = ParCompactionManager::region_array();
2360 2359 ParallelTaskTerminator terminator(active_gc_threads, qset);
2361 2360
2362 2361 PSParallelCompact::MarkAndPushClosure mark_and_push_closure(cm);
2363 2362 PSParallelCompact::FollowStackClosure follow_stack_closure(cm);
2364 2363
2365 2364 // Need new claim bits before marking starts.
2366 2365 ClassLoaderDataGraph::clear_claimed_marks();
2367 2366
2368 2367 {
2369 2368 GCTraceTime tm_m("par mark", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2370 2369
2371 2370 ParallelScavengeHeap::ParStrongRootsScope psrs;
2372 2371
2373 2372 GCTaskQueue* q = GCTaskQueue::create();
2374 2373
2375 2374 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::universe));
2376 2375 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::jni_handles));
2377 2376 // We scan the thread roots in parallel
2378 2377 Threads::create_thread_roots_marking_tasks(q);
2379 2378 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::object_synchronizer));
2380 2379 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::flat_profiler));
2381 2380 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::management));
2382 2381 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::system_dictionary));
2383 2382 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::class_loader_data));
2384 2383 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::jvmti));
2385 2384 q->enqueue(new MarkFromRootsTask(MarkFromRootsTask::code_cache));
2386 2385
2387 2386 if (active_gc_threads > 1) {
2388 2387 for (uint j = 0; j < active_gc_threads; j++) {
2389 2388 q->enqueue(new StealMarkingTask(&terminator));
2390 2389 }
2391 2390 }
2392 2391
2393 2392 gc_task_manager()->execute_and_wait(q);
2394 2393 }
2395 2394
2396 2395 // Process reference objects found during marking
2397 2396 {
2398 2397 GCTraceTime tm_r("reference processing", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2399 2398
2400 2399 ReferenceProcessorStats stats;
2401 2400 if (ref_processor()->processing_is_mt()) {
2402 2401 RefProcTaskExecutor task_executor;
2403 2402 stats = ref_processor()->process_discovered_references(
2404 2403 is_alive_closure(), &mark_and_push_closure, &follow_stack_closure,
2405 2404 &task_executor, &_gc_timer, _gc_tracer.gc_id());
2406 2405 } else {
2407 2406 stats = ref_processor()->process_discovered_references(
2408 2407 is_alive_closure(), &mark_and_push_closure, &follow_stack_closure, NULL,
2409 2408 &_gc_timer, _gc_tracer.gc_id());
2410 2409 }
2411 2410
2412 2411 gc_tracer->report_gc_reference_stats(stats);
2413 2412 }
2414 2413
2415 2414 GCTraceTime tm_c("class unloading", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2416 2415
2417 2416 // This is the point where the entire marking should have completed.
2418 2417 assert(cm->marking_stacks_empty(), "Marking should have completed");
2419 2418
2420 2419 // Follow system dictionary roots and unload classes.
2421 2420 bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
2422 2421
2423 2422 // Unload nmethods.
2424 2423 CodeCache::do_unloading(is_alive_closure(), purged_class);
2425 2424
2426 2425 // Prune dead klasses from subklass/sibling/implementor lists.
2427 2426 Klass::clean_weak_klass_links(is_alive_closure());
2428 2427
2429 2428 // Delete entries for dead interned strings.
2430 2429 StringTable::unlink(is_alive_closure());
2431 2430
2432 2431 // Clean up unreferenced symbols in symbol table.
2433 2432 SymbolTable::unlink();
2434 2433 _gc_tracer.report_object_count_after_gc(is_alive_closure());
2435 2434 }
2436 2435
2437 2436 void PSParallelCompact::follow_class_loader(ParCompactionManager* cm,
2438 2437 ClassLoaderData* cld) {
2439 2438 PSParallelCompact::MarkAndPushClosure mark_and_push_closure(cm);
2440 2439 PSParallelCompact::FollowKlassClosure follow_klass_closure(&mark_and_push_closure);
2441 2440
2442 2441 cld->oops_do(&mark_and_push_closure, &follow_klass_closure, true);
2443 2442 }
2444 2443
2445 2444 // This should be moved to the shared markSweep code!
2446 2445 class PSAlwaysTrueClosure: public BoolObjectClosure {
2447 2446 public:
2448 2447 bool do_object_b(oop p) { return true; }
2449 2448 };
2450 2449 static PSAlwaysTrueClosure always_true;
2451 2450
2452 2451 void PSParallelCompact::adjust_roots() {
2453 2452 // Adjust the pointers to reflect the new locations
2454 2453 GCTraceTime tm("adjust roots", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2455 2454
2456 2455 // Need new claim bits when tracing through and adjusting pointers.
2457 2456 ClassLoaderDataGraph::clear_claimed_marks();
2458 2457
2459 2458 // General strong roots.
2460 2459 Universe::oops_do(adjust_pointer_closure());
2461 2460 JNIHandles::oops_do(adjust_pointer_closure()); // Global (strong) JNI handles
2462 2461 CLDToOopClosure adjust_from_cld(adjust_pointer_closure());
2463 2462 Threads::oops_do(adjust_pointer_closure(), &adjust_from_cld, NULL);
2464 2463 ObjectSynchronizer::oops_do(adjust_pointer_closure());
2465 2464 FlatProfiler::oops_do(adjust_pointer_closure());
2466 2465 Management::oops_do(adjust_pointer_closure());
2467 2466 JvmtiExport::oops_do(adjust_pointer_closure());
2468 2467 SystemDictionary::oops_do(adjust_pointer_closure());
2469 2468 ClassLoaderDataGraph::oops_do(adjust_pointer_closure(), adjust_klass_closure(), true);
2470 2469
2471 2470 // Now adjust pointers in remaining weak roots. (All of which should
2472 2471 // have been cleared if they pointed to non-surviving objects.)
2473 2472 // Global (weak) JNI handles
2474 2473 JNIHandles::weak_oops_do(&always_true, adjust_pointer_closure());
2475 2474
2476 2475 CodeBlobToOopClosure adjust_from_blobs(adjust_pointer_closure(), CodeBlobToOopClosure::FixRelocations);
2477 2476 CodeCache::blobs_do(&adjust_from_blobs);
2478 2477 StringTable::oops_do(adjust_pointer_closure());
2479 2478 ref_processor()->weak_oops_do(adjust_pointer_closure());
2480 2479 // Roots were visited so references into the young gen in roots
2481 2480 // may have been scanned. Process them also.
2482 2481 // Should the reference processor have a span that excludes
2483 2482 // young gen objects?
2484 2483 PSScavenge::reference_processor()->weak_oops_do(adjust_pointer_closure());
2485 2484 }
2486 2485
2487 2486 void PSParallelCompact::enqueue_region_draining_tasks(GCTaskQueue* q,
2488 2487 uint parallel_gc_threads)
2489 2488 {
2490 2489 GCTraceTime tm("drain task setup", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2491 2490
2492 2491 // Find the threads that are active
2493 2492 unsigned int which = 0;
2494 2493
2495 2494 const uint task_count = MAX2(parallel_gc_threads, 1U);
2496 2495 for (uint j = 0; j < task_count; j++) {
2497 2496 q->enqueue(new DrainStacksCompactionTask(j));
2498 2497 ParCompactionManager::verify_region_list_empty(j);
2499 2498 // Set the region stacks variables to "no" region stack values
2500 2499 // so that they will be recognized and needing a region stack
2501 2500 // in the stealing tasks if they do not get one by executing
2502 2501 // a draining stack.
2503 2502 ParCompactionManager* cm = ParCompactionManager::manager_array(j);
2504 2503 cm->set_region_stack(NULL);
2505 2504 cm->set_region_stack_index((uint)max_uintx);
2506 2505 }
2507 2506 ParCompactionManager::reset_recycled_stack_index();
2508 2507
2509 2508 // Find all regions that are available (can be filled immediately) and
2510 2509 // distribute them to the thread stacks. The iteration is done in reverse
2511 2510 // order (high to low) so the regions will be removed in ascending order.
2512 2511
2513 2512 const ParallelCompactData& sd = PSParallelCompact::summary_data();
2514 2513
2515 2514 size_t fillable_regions = 0; // A count for diagnostic purposes.
2516 2515 // A region index which corresponds to the tasks created above.
2517 2516 // "which" must be 0 <= which < task_count
2518 2517
2519 2518 which = 0;
2520 2519 // id + 1 is used to test termination so unsigned can
2521 2520 // be used with an old_space_id == 0.
2522 2521 for (unsigned int id = to_space_id; id + 1 > old_space_id; --id) {
2523 2522 SpaceInfo* const space_info = _space_info + id;
2524 2523 MutableSpace* const space = space_info->space();
2525 2524 HeapWord* const new_top = space_info->new_top();
2526 2525
2527 2526 const size_t beg_region = sd.addr_to_region_idx(space_info->dense_prefix());
2528 2527 const size_t end_region =
2529 2528 sd.addr_to_region_idx(sd.region_align_up(new_top));
2530 2529
2531 2530 for (size_t cur = end_region - 1; cur + 1 > beg_region; --cur) {
2532 2531 if (sd.region(cur)->claim_unsafe()) {
2533 2532 ParCompactionManager::region_list_push(which, cur);
2534 2533
2535 2534 if (TraceParallelOldGCCompactionPhase && Verbose) {
2536 2535 const size_t count_mod_8 = fillable_regions & 7;
2537 2536 if (count_mod_8 == 0) gclog_or_tty->print("fillable: ");
2538 2537 gclog_or_tty->print(" " SIZE_FORMAT_W(7), cur);
2539 2538 if (count_mod_8 == 7) gclog_or_tty->cr();
2540 2539 }
2541 2540
2542 2541 NOT_PRODUCT(++fillable_regions;)
2543 2542
2544 2543 // Assign regions to tasks in round-robin fashion.
2545 2544 if (++which == task_count) {
2546 2545 assert(which <= parallel_gc_threads,
2547 2546 "Inconsistent number of workers");
2548 2547 which = 0;
2549 2548 }
2550 2549 }
2551 2550 }
2552 2551 }
2553 2552
2554 2553 if (TraceParallelOldGCCompactionPhase) {
2555 2554 if (Verbose && (fillable_regions & 7) != 0) gclog_or_tty->cr();
2556 2555 gclog_or_tty->print_cr("%u initially fillable regions", fillable_regions);
2557 2556 }
2558 2557 }
2559 2558
2560 2559 #define PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING 4
2561 2560
2562 2561 void PSParallelCompact::enqueue_dense_prefix_tasks(GCTaskQueue* q,
2563 2562 uint parallel_gc_threads) {
2564 2563 GCTraceTime tm("dense prefix task setup", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2565 2564
2566 2565 ParallelCompactData& sd = PSParallelCompact::summary_data();
2567 2566
2568 2567 // Iterate over all the spaces adding tasks for updating
2569 2568 // regions in the dense prefix. Assume that 1 gc thread
2570 2569 // will work on opening the gaps and the remaining gc threads
2571 2570 // will work on the dense prefix.
2572 2571 unsigned int space_id;
2573 2572 for (space_id = old_space_id; space_id < last_space_id; ++ space_id) {
2574 2573 HeapWord* const dense_prefix_end = _space_info[space_id].dense_prefix();
2575 2574 const MutableSpace* const space = _space_info[space_id].space();
2576 2575
2577 2576 if (dense_prefix_end == space->bottom()) {
2578 2577 // There is no dense prefix for this space.
2579 2578 continue;
2580 2579 }
2581 2580
2582 2581 // The dense prefix is before this region.
2583 2582 size_t region_index_end_dense_prefix =
2584 2583 sd.addr_to_region_idx(dense_prefix_end);
2585 2584 RegionData* const dense_prefix_cp =
2586 2585 sd.region(region_index_end_dense_prefix);
2587 2586 assert(dense_prefix_end == space->end() ||
2588 2587 dense_prefix_cp->available() ||
2589 2588 dense_prefix_cp->claimed(),
2590 2589 "The region after the dense prefix should always be ready to fill");
2591 2590
2592 2591 size_t region_index_start = sd.addr_to_region_idx(space->bottom());
2593 2592
2594 2593 // Is there dense prefix work?
2595 2594 size_t total_dense_prefix_regions =
2596 2595 region_index_end_dense_prefix - region_index_start;
2597 2596 // How many regions of the dense prefix should be given to
2598 2597 // each thread?
2599 2598 if (total_dense_prefix_regions > 0) {
2600 2599 uint tasks_for_dense_prefix = 1;
2601 2600 if (total_dense_prefix_regions <=
2602 2601 (parallel_gc_threads * PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING)) {
2603 2602 // Don't over partition. This assumes that
2604 2603 // PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING is a small integer value
2605 2604 // so there are not many regions to process.
2606 2605 tasks_for_dense_prefix = parallel_gc_threads;
2607 2606 } else {
2608 2607 // Over partition
2609 2608 tasks_for_dense_prefix = parallel_gc_threads *
2610 2609 PAR_OLD_DENSE_PREFIX_OVER_PARTITIONING;
2611 2610 }
2612 2611 size_t regions_per_thread = total_dense_prefix_regions /
2613 2612 tasks_for_dense_prefix;
2614 2613 // Give each thread at least 1 region.
2615 2614 if (regions_per_thread == 0) {
2616 2615 regions_per_thread = 1;
2617 2616 }
2618 2617
2619 2618 for (uint k = 0; k < tasks_for_dense_prefix; k++) {
2620 2619 if (region_index_start >= region_index_end_dense_prefix) {
2621 2620 break;
2622 2621 }
2623 2622 // region_index_end is not processed
2624 2623 size_t region_index_end = MIN2(region_index_start + regions_per_thread,
2625 2624 region_index_end_dense_prefix);
2626 2625 q->enqueue(new UpdateDensePrefixTask(SpaceId(space_id),
2627 2626 region_index_start,
2628 2627 region_index_end));
2629 2628 region_index_start = region_index_end;
2630 2629 }
2631 2630 }
2632 2631 // This gets any part of the dense prefix that did not
2633 2632 // fit evenly.
2634 2633 if (region_index_start < region_index_end_dense_prefix) {
2635 2634 q->enqueue(new UpdateDensePrefixTask(SpaceId(space_id),
2636 2635 region_index_start,
2637 2636 region_index_end_dense_prefix));
2638 2637 }
2639 2638 }
2640 2639 }
2641 2640
2642 2641 void PSParallelCompact::enqueue_region_stealing_tasks(
2643 2642 GCTaskQueue* q,
2644 2643 ParallelTaskTerminator* terminator_ptr,
2645 2644 uint parallel_gc_threads) {
2646 2645 GCTraceTime tm("steal task setup", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2647 2646
2648 2647 // Once a thread has drained it's stack, it should try to steal regions from
2649 2648 // other threads.
2650 2649 if (parallel_gc_threads > 1) {
2651 2650 for (uint j = 0; j < parallel_gc_threads; j++) {
2652 2651 q->enqueue(new StealRegionCompactionTask(terminator_ptr));
2653 2652 }
2654 2653 }
2655 2654 }
2656 2655
2657 2656 #ifdef ASSERT
2658 2657 // Write a histogram of the number of times the block table was filled for a
2659 2658 // region.
2660 2659 void PSParallelCompact::write_block_fill_histogram(outputStream* const out)
2661 2660 {
2662 2661 if (!TraceParallelOldGCCompactionPhase) return;
2663 2662
2664 2663 typedef ParallelCompactData::RegionData rd_t;
2665 2664 ParallelCompactData& sd = summary_data();
2666 2665
2667 2666 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
2668 2667 MutableSpace* const spc = _space_info[id].space();
2669 2668 if (spc->bottom() != spc->top()) {
2670 2669 const rd_t* const beg = sd.addr_to_region_ptr(spc->bottom());
2671 2670 HeapWord* const top_aligned_up = sd.region_align_up(spc->top());
2672 2671 const rd_t* const end = sd.addr_to_region_ptr(top_aligned_up);
2673 2672
2674 2673 size_t histo[5] = { 0, 0, 0, 0, 0 };
2675 2674 const size_t histo_len = sizeof(histo) / sizeof(size_t);
2676 2675 const size_t region_cnt = pointer_delta(end, beg, sizeof(rd_t));
2677 2676
2678 2677 for (const rd_t* cur = beg; cur < end; ++cur) {
2679 2678 ++histo[MIN2(cur->blocks_filled_count(), histo_len - 1)];
2680 2679 }
2681 2680 out->print("%u %-4s" SIZE_FORMAT_W(5), id, space_names[id], region_cnt);
2682 2681 for (size_t i = 0; i < histo_len; ++i) {
2683 2682 out->print(" " SIZE_FORMAT_W(5) " %5.1f%%",
2684 2683 histo[i], 100.0 * histo[i] / region_cnt);
2685 2684 }
2686 2685 out->cr();
2687 2686 }
2688 2687 }
2689 2688 }
2690 2689 #endif // #ifdef ASSERT
2691 2690
2692 2691 void PSParallelCompact::compact() {
2693 2692 // trace("5");
2694 2693 GCTraceTime tm("compaction phase", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2695 2694
2696 2695 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
2697 2696 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
2698 2697 PSOldGen* old_gen = heap->old_gen();
2699 2698 old_gen->start_array()->reset();
2700 2699 uint parallel_gc_threads = heap->gc_task_manager()->workers();
2701 2700 uint active_gc_threads = heap->gc_task_manager()->active_workers();
2702 2701 TaskQueueSetSuper* qset = ParCompactionManager::region_array();
2703 2702 ParallelTaskTerminator terminator(active_gc_threads, qset);
2704 2703
2705 2704 GCTaskQueue* q = GCTaskQueue::create();
2706 2705 enqueue_region_draining_tasks(q, active_gc_threads);
2707 2706 enqueue_dense_prefix_tasks(q, active_gc_threads);
2708 2707 enqueue_region_stealing_tasks(q, &terminator, active_gc_threads);
2709 2708
2710 2709 {
2711 2710 GCTraceTime tm_pc("par compact", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2712 2711
2713 2712 gc_task_manager()->execute_and_wait(q);
2714 2713
2715 2714 #ifdef ASSERT
2716 2715 // Verify that all regions have been processed before the deferred updates.
2717 2716 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
2718 2717 verify_complete(SpaceId(id));
2719 2718 }
2720 2719 #endif
2721 2720 }
2722 2721
2723 2722 {
2724 2723 // Update the deferred objects, if any. Any compaction manager can be used.
2725 2724 GCTraceTime tm_du("deferred updates", print_phases(), true, &_gc_timer, _gc_tracer.gc_id());
2726 2725 ParCompactionManager* cm = ParCompactionManager::manager_array(0);
2727 2726 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
2728 2727 update_deferred_objects(cm, SpaceId(id));
2729 2728 }
2730 2729 }
2731 2730
2732 2731 DEBUG_ONLY(write_block_fill_histogram(gclog_or_tty));
2733 2732 }
2734 2733
2735 2734 #ifdef ASSERT
2736 2735 void PSParallelCompact::verify_complete(SpaceId space_id) {
2737 2736 // All Regions between space bottom() to new_top() should be marked as filled
2738 2737 // and all Regions between new_top() and top() should be available (i.e.,
2739 2738 // should have been emptied).
2740 2739 ParallelCompactData& sd = summary_data();
2741 2740 SpaceInfo si = _space_info[space_id];
2742 2741 HeapWord* new_top_addr = sd.region_align_up(si.new_top());
2743 2742 HeapWord* old_top_addr = sd.region_align_up(si.space()->top());
2744 2743 const size_t beg_region = sd.addr_to_region_idx(si.space()->bottom());
2745 2744 const size_t new_top_region = sd.addr_to_region_idx(new_top_addr);
2746 2745 const size_t old_top_region = sd.addr_to_region_idx(old_top_addr);
2747 2746
2748 2747 bool issued_a_warning = false;
2749 2748
2750 2749 size_t cur_region;
2751 2750 for (cur_region = beg_region; cur_region < new_top_region; ++cur_region) {
2752 2751 const RegionData* const c = sd.region(cur_region);
2753 2752 if (!c->completed()) {
2754 2753 warning("region " SIZE_FORMAT " not filled: "
2755 2754 "destination_count=" SIZE_FORMAT,
2756 2755 cur_region, c->destination_count());
2757 2756 issued_a_warning = true;
2758 2757 }
2759 2758 }
2760 2759
2761 2760 for (cur_region = new_top_region; cur_region < old_top_region; ++cur_region) {
2762 2761 const RegionData* const c = sd.region(cur_region);
2763 2762 if (!c->available()) {
2764 2763 warning("region " SIZE_FORMAT " not empty: "
2765 2764 "destination_count=" SIZE_FORMAT,
2766 2765 cur_region, c->destination_count());
2767 2766 issued_a_warning = true;
2768 2767 }
2769 2768 }
2770 2769
2771 2770 if (issued_a_warning) {
2772 2771 print_region_ranges();
2773 2772 }
2774 2773 }
2775 2774 #endif // #ifdef ASSERT
2776 2775
2777 2776 // Update interior oops in the ranges of regions [beg_region, end_region).
2778 2777 void
2779 2778 PSParallelCompact::update_and_deadwood_in_dense_prefix(ParCompactionManager* cm,
2780 2779 SpaceId space_id,
2781 2780 size_t beg_region,
2782 2781 size_t end_region) {
2783 2782 ParallelCompactData& sd = summary_data();
2784 2783 ParMarkBitMap* const mbm = mark_bitmap();
2785 2784
2786 2785 HeapWord* beg_addr = sd.region_to_addr(beg_region);
2787 2786 HeapWord* const end_addr = sd.region_to_addr(end_region);
2788 2787 assert(beg_region <= end_region, "bad region range");
2789 2788 assert(end_addr <= dense_prefix(space_id), "not in the dense prefix");
2790 2789
2791 2790 #ifdef ASSERT
2792 2791 // Claim the regions to avoid triggering an assert when they are marked as
2793 2792 // filled.
2794 2793 for (size_t claim_region = beg_region; claim_region < end_region; ++claim_region) {
2795 2794 assert(sd.region(claim_region)->claim_unsafe(), "claim() failed");
2796 2795 }
2797 2796 #endif // #ifdef ASSERT
2798 2797
2799 2798 if (beg_addr != space(space_id)->bottom()) {
2800 2799 // Find the first live object or block of dead space that *starts* in this
2801 2800 // range of regions. If a partial object crosses onto the region, skip it;
2802 2801 // it will be marked for 'deferred update' when the object head is
2803 2802 // processed. If dead space crosses onto the region, it is also skipped; it
2804 2803 // will be filled when the prior region is processed. If neither of those
2805 2804 // apply, the first word in the region is the start of a live object or dead
2806 2805 // space.
2807 2806 assert(beg_addr > space(space_id)->bottom(), "sanity");
2808 2807 const RegionData* const cp = sd.region(beg_region);
2809 2808 if (cp->partial_obj_size() != 0) {
2810 2809 beg_addr = sd.partial_obj_end(beg_region);
2811 2810 } else if (dead_space_crosses_boundary(cp, mbm->addr_to_bit(beg_addr))) {
2812 2811 beg_addr = mbm->find_obj_beg(beg_addr, end_addr);
2813 2812 }
2814 2813 }
2815 2814
2816 2815 if (beg_addr < end_addr) {
2817 2816 // A live object or block of dead space starts in this range of Regions.
2818 2817 HeapWord* const dense_prefix_end = dense_prefix(space_id);
2819 2818
2820 2819 // Create closures and iterate.
2821 2820 UpdateOnlyClosure update_closure(mbm, cm, space_id);
2822 2821 FillClosure fill_closure(cm, space_id);
2823 2822 ParMarkBitMap::IterationStatus status;
2824 2823 status = mbm->iterate(&update_closure, &fill_closure, beg_addr, end_addr,
2825 2824 dense_prefix_end);
2826 2825 if (status == ParMarkBitMap::incomplete) {
2827 2826 update_closure.do_addr(update_closure.source());
2828 2827 }
2829 2828 }
2830 2829
2831 2830 // Mark the regions as filled.
2832 2831 RegionData* const beg_cp = sd.region(beg_region);
2833 2832 RegionData* const end_cp = sd.region(end_region);
2834 2833 for (RegionData* cp = beg_cp; cp < end_cp; ++cp) {
2835 2834 cp->set_completed();
2836 2835 }
2837 2836 }
2838 2837
2839 2838 // Return the SpaceId for the space containing addr. If addr is not in the
2840 2839 // heap, last_space_id is returned. In debug mode it expects the address to be
2841 2840 // in the heap and asserts such.
2842 2841 PSParallelCompact::SpaceId PSParallelCompact::space_id(HeapWord* addr) {
2843 2842 assert(Universe::heap()->is_in_reserved(addr), "addr not in the heap");
2844 2843
2845 2844 for (unsigned int id = old_space_id; id < last_space_id; ++id) {
2846 2845 if (_space_info[id].space()->contains(addr)) {
2847 2846 return SpaceId(id);
2848 2847 }
2849 2848 }
2850 2849
2851 2850 assert(false, "no space contains the addr");
2852 2851 return last_space_id;
2853 2852 }
2854 2853
2855 2854 void PSParallelCompact::update_deferred_objects(ParCompactionManager* cm,
2856 2855 SpaceId id) {
2857 2856 assert(id < last_space_id, "bad space id");
2858 2857
2859 2858 ParallelCompactData& sd = summary_data();
2860 2859 const SpaceInfo* const space_info = _space_info + id;
2861 2860 ObjectStartArray* const start_array = space_info->start_array();
2862 2861
2863 2862 const MutableSpace* const space = space_info->space();
2864 2863 assert(space_info->dense_prefix() >= space->bottom(), "dense_prefix not set");
2865 2864 HeapWord* const beg_addr = space_info->dense_prefix();
2866 2865 HeapWord* const end_addr = sd.region_align_up(space_info->new_top());
2867 2866
2868 2867 const RegionData* const beg_region = sd.addr_to_region_ptr(beg_addr);
2869 2868 const RegionData* const end_region = sd.addr_to_region_ptr(end_addr);
2870 2869 const RegionData* cur_region;
2871 2870 for (cur_region = beg_region; cur_region < end_region; ++cur_region) {
2872 2871 HeapWord* const addr = cur_region->deferred_obj_addr();
2873 2872 if (addr != NULL) {
2874 2873 if (start_array != NULL) {
2875 2874 start_array->allocate_block(addr);
2876 2875 }
2877 2876 oop(addr)->update_contents(cm);
2878 2877 assert(oop(addr)->is_oop_or_null(), "should be an oop now");
2879 2878 }
2880 2879 }
2881 2880 }
2882 2881
2883 2882 // Skip over count live words starting from beg, and return the address of the
2884 2883 // next live word. Unless marked, the word corresponding to beg is assumed to
2885 2884 // be dead. Callers must either ensure beg does not correspond to the middle of
2886 2885 // an object, or account for those live words in some other way. Callers must
2887 2886 // also ensure that there are enough live words in the range [beg, end) to skip.
2888 2887 HeapWord*
2889 2888 PSParallelCompact::skip_live_words(HeapWord* beg, HeapWord* end, size_t count)
2890 2889 {
2891 2890 assert(count > 0, "sanity");
2892 2891
2893 2892 ParMarkBitMap* m = mark_bitmap();
2894 2893 idx_t bits_to_skip = m->words_to_bits(count);
2895 2894 idx_t cur_beg = m->addr_to_bit(beg);
2896 2895 const idx_t search_end = BitMap::word_align_up(m->addr_to_bit(end));
2897 2896
2898 2897 do {
2899 2898 cur_beg = m->find_obj_beg(cur_beg, search_end);
2900 2899 idx_t cur_end = m->find_obj_end(cur_beg, search_end);
2901 2900 const size_t obj_bits = cur_end - cur_beg + 1;
2902 2901 if (obj_bits > bits_to_skip) {
2903 2902 return m->bit_to_addr(cur_beg + bits_to_skip);
2904 2903 }
2905 2904 bits_to_skip -= obj_bits;
2906 2905 cur_beg = cur_end + 1;
2907 2906 } while (bits_to_skip > 0);
2908 2907
2909 2908 // Skipping the desired number of words landed just past the end of an object.
2910 2909 // Find the start of the next object.
2911 2910 cur_beg = m->find_obj_beg(cur_beg, search_end);
2912 2911 assert(cur_beg < m->addr_to_bit(end), "not enough live words to skip");
2913 2912 return m->bit_to_addr(cur_beg);
2914 2913 }
2915 2914
2916 2915 HeapWord* PSParallelCompact::first_src_addr(HeapWord* const dest_addr,
2917 2916 SpaceId src_space_id,
2918 2917 size_t src_region_idx)
2919 2918 {
2920 2919 assert(summary_data().is_region_aligned(dest_addr), "not aligned");
2921 2920
2922 2921 const SplitInfo& split_info = _space_info[src_space_id].split_info();
2923 2922 if (split_info.dest_region_addr() == dest_addr) {
2924 2923 // The partial object ending at the split point contains the first word to
2925 2924 // be copied to dest_addr.
2926 2925 return split_info.first_src_addr();
2927 2926 }
2928 2927
2929 2928 const ParallelCompactData& sd = summary_data();
2930 2929 ParMarkBitMap* const bitmap = mark_bitmap();
2931 2930 const size_t RegionSize = ParallelCompactData::RegionSize;
2932 2931
2933 2932 assert(sd.is_region_aligned(dest_addr), "not aligned");
2934 2933 const RegionData* const src_region_ptr = sd.region(src_region_idx);
2935 2934 const size_t partial_obj_size = src_region_ptr->partial_obj_size();
2936 2935 HeapWord* const src_region_destination = src_region_ptr->destination();
2937 2936
2938 2937 assert(dest_addr >= src_region_destination, "wrong src region");
2939 2938 assert(src_region_ptr->data_size() > 0, "src region cannot be empty");
2940 2939
2941 2940 HeapWord* const src_region_beg = sd.region_to_addr(src_region_idx);
2942 2941 HeapWord* const src_region_end = src_region_beg + RegionSize;
2943 2942
2944 2943 HeapWord* addr = src_region_beg;
2945 2944 if (dest_addr == src_region_destination) {
2946 2945 // Return the first live word in the source region.
2947 2946 if (partial_obj_size == 0) {
2948 2947 addr = bitmap->find_obj_beg(addr, src_region_end);
2949 2948 assert(addr < src_region_end, "no objects start in src region");
2950 2949 }
2951 2950 return addr;
2952 2951 }
2953 2952
2954 2953 // Must skip some live data.
2955 2954 size_t words_to_skip = dest_addr - src_region_destination;
2956 2955 assert(src_region_ptr->data_size() > words_to_skip, "wrong src region");
2957 2956
2958 2957 if (partial_obj_size >= words_to_skip) {
2959 2958 // All the live words to skip are part of the partial object.
2960 2959 addr += words_to_skip;
2961 2960 if (partial_obj_size == words_to_skip) {
2962 2961 // Find the first live word past the partial object.
2963 2962 addr = bitmap->find_obj_beg(addr, src_region_end);
2964 2963 assert(addr < src_region_end, "wrong src region");
2965 2964 }
2966 2965 return addr;
2967 2966 }
2968 2967
2969 2968 // Skip over the partial object (if any).
2970 2969 if (partial_obj_size != 0) {
2971 2970 words_to_skip -= partial_obj_size;
2972 2971 addr += partial_obj_size;
2973 2972 }
2974 2973
2975 2974 // Skip over live words due to objects that start in the region.
2976 2975 addr = skip_live_words(addr, src_region_end, words_to_skip);
2977 2976 assert(addr < src_region_end, "wrong src region");
2978 2977 return addr;
2979 2978 }
2980 2979
2981 2980 void PSParallelCompact::decrement_destination_counts(ParCompactionManager* cm,
2982 2981 SpaceId src_space_id,
2983 2982 size_t beg_region,
2984 2983 HeapWord* end_addr)
2985 2984 {
2986 2985 ParallelCompactData& sd = summary_data();
2987 2986
2988 2987 #ifdef ASSERT
2989 2988 MutableSpace* const src_space = _space_info[src_space_id].space();
2990 2989 HeapWord* const beg_addr = sd.region_to_addr(beg_region);
2991 2990 assert(src_space->contains(beg_addr) || beg_addr == src_space->end(),
2992 2991 "src_space_id does not match beg_addr");
2993 2992 assert(src_space->contains(end_addr) || end_addr == src_space->end(),
2994 2993 "src_space_id does not match end_addr");
2995 2994 #endif // #ifdef ASSERT
2996 2995
2997 2996 RegionData* const beg = sd.region(beg_region);
2998 2997 RegionData* const end = sd.addr_to_region_ptr(sd.region_align_up(end_addr));
2999 2998
3000 2999 // Regions up to new_top() are enqueued if they become available.
3001 3000 HeapWord* const new_top = _space_info[src_space_id].new_top();
3002 3001 RegionData* const enqueue_end =
3003 3002 sd.addr_to_region_ptr(sd.region_align_up(new_top));
3004 3003
3005 3004 for (RegionData* cur = beg; cur < end; ++cur) {
3006 3005 assert(cur->data_size() > 0, "region must have live data");
3007 3006 cur->decrement_destination_count();
3008 3007 if (cur < enqueue_end && cur->available() && cur->claim()) {
3009 3008 cm->push_region(sd.region(cur));
3010 3009 }
3011 3010 }
3012 3011 }
3013 3012
3014 3013 size_t PSParallelCompact::next_src_region(MoveAndUpdateClosure& closure,
3015 3014 SpaceId& src_space_id,
3016 3015 HeapWord*& src_space_top,
3017 3016 HeapWord* end_addr)
3018 3017 {
3019 3018 typedef ParallelCompactData::RegionData RegionData;
3020 3019
3021 3020 ParallelCompactData& sd = PSParallelCompact::summary_data();
3022 3021 const size_t region_size = ParallelCompactData::RegionSize;
3023 3022
3024 3023 size_t src_region_idx = 0;
3025 3024
3026 3025 // Skip empty regions (if any) up to the top of the space.
3027 3026 HeapWord* const src_aligned_up = sd.region_align_up(end_addr);
3028 3027 RegionData* src_region_ptr = sd.addr_to_region_ptr(src_aligned_up);
3029 3028 HeapWord* const top_aligned_up = sd.region_align_up(src_space_top);
3030 3029 const RegionData* const top_region_ptr =
3031 3030 sd.addr_to_region_ptr(top_aligned_up);
3032 3031 while (src_region_ptr < top_region_ptr && src_region_ptr->data_size() == 0) {
3033 3032 ++src_region_ptr;
3034 3033 }
3035 3034
3036 3035 if (src_region_ptr < top_region_ptr) {
3037 3036 // The next source region is in the current space. Update src_region_idx
3038 3037 // and the source address to match src_region_ptr.
3039 3038 src_region_idx = sd.region(src_region_ptr);
3040 3039 HeapWord* const src_region_addr = sd.region_to_addr(src_region_idx);
3041 3040 if (src_region_addr > closure.source()) {
3042 3041 closure.set_source(src_region_addr);
3043 3042 }
3044 3043 return src_region_idx;
3045 3044 }
3046 3045
3047 3046 // Switch to a new source space and find the first non-empty region.
3048 3047 unsigned int space_id = src_space_id + 1;
3049 3048 assert(space_id < last_space_id, "not enough spaces");
3050 3049
3051 3050 HeapWord* const destination = closure.destination();
3052 3051
3053 3052 do {
3054 3053 MutableSpace* space = _space_info[space_id].space();
3055 3054 HeapWord* const bottom = space->bottom();
3056 3055 const RegionData* const bottom_cp = sd.addr_to_region_ptr(bottom);
3057 3056
3058 3057 // Iterate over the spaces that do not compact into themselves.
3059 3058 if (bottom_cp->destination() != bottom) {
3060 3059 HeapWord* const top_aligned_up = sd.region_align_up(space->top());
3061 3060 const RegionData* const top_cp = sd.addr_to_region_ptr(top_aligned_up);
3062 3061
3063 3062 for (const RegionData* src_cp = bottom_cp; src_cp < top_cp; ++src_cp) {
3064 3063 if (src_cp->live_obj_size() > 0) {
3065 3064 // Found it.
3066 3065 assert(src_cp->destination() == destination,
3067 3066 "first live obj in the space must match the destination");
3068 3067 assert(src_cp->partial_obj_size() == 0,
3069 3068 "a space cannot begin with a partial obj");
3070 3069
3071 3070 src_space_id = SpaceId(space_id);
3072 3071 src_space_top = space->top();
3073 3072 const size_t src_region_idx = sd.region(src_cp);
3074 3073 closure.set_source(sd.region_to_addr(src_region_idx));
3075 3074 return src_region_idx;
3076 3075 } else {
3077 3076 assert(src_cp->data_size() == 0, "sanity");
3078 3077 }
3079 3078 }
3080 3079 }
3081 3080 } while (++space_id < last_space_id);
3082 3081
3083 3082 assert(false, "no source region was found");
3084 3083 return 0;
3085 3084 }
3086 3085
3087 3086 void PSParallelCompact::fill_region(ParCompactionManager* cm, size_t region_idx)
3088 3087 {
3089 3088 typedef ParMarkBitMap::IterationStatus IterationStatus;
3090 3089 const size_t RegionSize = ParallelCompactData::RegionSize;
3091 3090 ParMarkBitMap* const bitmap = mark_bitmap();
3092 3091 ParallelCompactData& sd = summary_data();
3093 3092 RegionData* const region_ptr = sd.region(region_idx);
3094 3093
3095 3094 // Get the items needed to construct the closure.
3096 3095 HeapWord* dest_addr = sd.region_to_addr(region_idx);
3097 3096 SpaceId dest_space_id = space_id(dest_addr);
3098 3097 ObjectStartArray* start_array = _space_info[dest_space_id].start_array();
3099 3098 HeapWord* new_top = _space_info[dest_space_id].new_top();
3100 3099 assert(dest_addr < new_top, "sanity");
3101 3100 const size_t words = MIN2(pointer_delta(new_top, dest_addr), RegionSize);
3102 3101
3103 3102 // Get the source region and related info.
3104 3103 size_t src_region_idx = region_ptr->source_region();
3105 3104 SpaceId src_space_id = space_id(sd.region_to_addr(src_region_idx));
3106 3105 HeapWord* src_space_top = _space_info[src_space_id].space()->top();
3107 3106
3108 3107 MoveAndUpdateClosure closure(bitmap, cm, start_array, dest_addr, words);
3109 3108 closure.set_source(first_src_addr(dest_addr, src_space_id, src_region_idx));
3110 3109
3111 3110 // Adjust src_region_idx to prepare for decrementing destination counts (the
3112 3111 // destination count is not decremented when a region is copied to itself).
3113 3112 if (src_region_idx == region_idx) {
3114 3113 src_region_idx += 1;
3115 3114 }
3116 3115
3117 3116 if (bitmap->is_unmarked(closure.source())) {
3118 3117 // The first source word is in the middle of an object; copy the remainder
3119 3118 // of the object or as much as will fit. The fact that pointer updates were
3120 3119 // deferred will be noted when the object header is processed.
3121 3120 HeapWord* const old_src_addr = closure.source();
3122 3121 closure.copy_partial_obj();
3123 3122 if (closure.is_full()) {
3124 3123 decrement_destination_counts(cm, src_space_id, src_region_idx,
3125 3124 closure.source());
3126 3125 region_ptr->set_deferred_obj_addr(NULL);
3127 3126 region_ptr->set_completed();
3128 3127 return;
3129 3128 }
3130 3129
3131 3130 HeapWord* const end_addr = sd.region_align_down(closure.source());
3132 3131 if (sd.region_align_down(old_src_addr) != end_addr) {
3133 3132 // The partial object was copied from more than one source region.
3134 3133 decrement_destination_counts(cm, src_space_id, src_region_idx, end_addr);
3135 3134
3136 3135 // Move to the next source region, possibly switching spaces as well. All
3137 3136 // args except end_addr may be modified.
3138 3137 src_region_idx = next_src_region(closure, src_space_id, src_space_top,
3139 3138 end_addr);
3140 3139 }
3141 3140 }
3142 3141
3143 3142 do {
3144 3143 HeapWord* const cur_addr = closure.source();
3145 3144 HeapWord* const end_addr = MIN2(sd.region_align_up(cur_addr + 1),
3146 3145 src_space_top);
3147 3146 IterationStatus status = bitmap->iterate(&closure, cur_addr, end_addr);
3148 3147
3149 3148 if (status == ParMarkBitMap::incomplete) {
3150 3149 // The last obj that starts in the source region does not end in the
3151 3150 // region.
3152 3151 assert(closure.source() < end_addr, "sanity");
3153 3152 HeapWord* const obj_beg = closure.source();
3154 3153 HeapWord* const range_end = MIN2(obj_beg + closure.words_remaining(),
3155 3154 src_space_top);
3156 3155 HeapWord* const obj_end = bitmap->find_obj_end(obj_beg, range_end);
3157 3156 if (obj_end < range_end) {
3158 3157 // The end was found; the entire object will fit.
3159 3158 status = closure.do_addr(obj_beg, bitmap->obj_size(obj_beg, obj_end));
3160 3159 assert(status != ParMarkBitMap::would_overflow, "sanity");
3161 3160 } else {
3162 3161 // The end was not found; the object will not fit.
3163 3162 assert(range_end < src_space_top, "obj cannot cross space boundary");
3164 3163 status = ParMarkBitMap::would_overflow;
3165 3164 }
3166 3165 }
3167 3166
3168 3167 if (status == ParMarkBitMap::would_overflow) {
3169 3168 // The last object did not fit. Note that interior oop updates were
3170 3169 // deferred, then copy enough of the object to fill the region.
3171 3170 region_ptr->set_deferred_obj_addr(closure.destination());
3172 3171 status = closure.copy_until_full(); // copies from closure.source()
3173 3172
3174 3173 decrement_destination_counts(cm, src_space_id, src_region_idx,
3175 3174 closure.source());
3176 3175 region_ptr->set_completed();
3177 3176 return;
3178 3177 }
3179 3178
3180 3179 if (status == ParMarkBitMap::full) {
3181 3180 decrement_destination_counts(cm, src_space_id, src_region_idx,
3182 3181 closure.source());
3183 3182 region_ptr->set_deferred_obj_addr(NULL);
3184 3183 region_ptr->set_completed();
3185 3184 return;
3186 3185 }
3187 3186
3188 3187 decrement_destination_counts(cm, src_space_id, src_region_idx, end_addr);
3189 3188
3190 3189 // Move to the next source region, possibly switching spaces as well. All
3191 3190 // args except end_addr may be modified.
3192 3191 src_region_idx = next_src_region(closure, src_space_id, src_space_top,
3193 3192 end_addr);
3194 3193 } while (true);
3195 3194 }
3196 3195
3197 3196 void PSParallelCompact::fill_blocks(size_t region_idx)
3198 3197 {
3199 3198 // Fill in the block table elements for the specified region. Each block
3200 3199 // table element holds the number of live words in the region that are to the
3201 3200 // left of the first object that starts in the block. Thus only blocks in
3202 3201 // which an object starts need to be filled.
3203 3202 //
3204 3203 // The algorithm scans the section of the bitmap that corresponds to the
3205 3204 // region, keeping a running total of the live words. When an object start is
3206 3205 // found, if it's the first to start in the block that contains it, the
3207 3206 // current total is written to the block table element.
3208 3207 const size_t Log2BlockSize = ParallelCompactData::Log2BlockSize;
3209 3208 const size_t Log2RegionSize = ParallelCompactData::Log2RegionSize;
3210 3209 const size_t RegionSize = ParallelCompactData::RegionSize;
3211 3210
3212 3211 ParallelCompactData& sd = summary_data();
3213 3212 const size_t partial_obj_size = sd.region(region_idx)->partial_obj_size();
3214 3213 if (partial_obj_size >= RegionSize) {
3215 3214 return; // No objects start in this region.
3216 3215 }
3217 3216
3218 3217 // Ensure the first loop iteration decides that the block has changed.
3219 3218 size_t cur_block = sd.block_count();
3220 3219
3221 3220 const ParMarkBitMap* const bitmap = mark_bitmap();
3222 3221
3223 3222 const size_t Log2BitsPerBlock = Log2BlockSize - LogMinObjAlignment;
3224 3223 assert((size_t)1 << Log2BitsPerBlock ==
3225 3224 bitmap->words_to_bits(ParallelCompactData::BlockSize), "sanity");
3226 3225
3227 3226 size_t beg_bit = bitmap->words_to_bits(region_idx << Log2RegionSize);
3228 3227 const size_t range_end = beg_bit + bitmap->words_to_bits(RegionSize);
3229 3228 size_t live_bits = bitmap->words_to_bits(partial_obj_size);
3230 3229 beg_bit = bitmap->find_obj_beg(beg_bit + live_bits, range_end);
3231 3230 while (beg_bit < range_end) {
3232 3231 const size_t new_block = beg_bit >> Log2BitsPerBlock;
3233 3232 if (new_block != cur_block) {
3234 3233 cur_block = new_block;
3235 3234 sd.block(cur_block)->set_offset(bitmap->bits_to_words(live_bits));
3236 3235 }
3237 3236
3238 3237 const size_t end_bit = bitmap->find_obj_end(beg_bit, range_end);
3239 3238 if (end_bit < range_end - 1) {
3240 3239 live_bits += end_bit - beg_bit + 1;
3241 3240 beg_bit = bitmap->find_obj_beg(end_bit + 1, range_end);
3242 3241 } else {
3243 3242 return;
3244 3243 }
3245 3244 }
3246 3245 }
3247 3246
3248 3247 void
3249 3248 PSParallelCompact::move_and_update(ParCompactionManager* cm, SpaceId space_id) {
3250 3249 const MutableSpace* sp = space(space_id);
3251 3250 if (sp->is_empty()) {
3252 3251 return;
3253 3252 }
3254 3253
3255 3254 ParallelCompactData& sd = PSParallelCompact::summary_data();
3256 3255 ParMarkBitMap* const bitmap = mark_bitmap();
3257 3256 HeapWord* const dp_addr = dense_prefix(space_id);
3258 3257 HeapWord* beg_addr = sp->bottom();
3259 3258 HeapWord* end_addr = sp->top();
3260 3259
3261 3260 assert(beg_addr <= dp_addr && dp_addr <= end_addr, "bad dense prefix");
3262 3261
3263 3262 const size_t beg_region = sd.addr_to_region_idx(beg_addr);
3264 3263 const size_t dp_region = sd.addr_to_region_idx(dp_addr);
3265 3264 if (beg_region < dp_region) {
3266 3265 update_and_deadwood_in_dense_prefix(cm, space_id, beg_region, dp_region);
3267 3266 }
3268 3267
3269 3268 // The destination of the first live object that starts in the region is one
3270 3269 // past the end of the partial object entering the region (if any).
3271 3270 HeapWord* const dest_addr = sd.partial_obj_end(dp_region);
3272 3271 HeapWord* const new_top = _space_info[space_id].new_top();
3273 3272 assert(new_top >= dest_addr, "bad new_top value");
3274 3273 const size_t words = pointer_delta(new_top, dest_addr);
3275 3274
3276 3275 if (words > 0) {
3277 3276 ObjectStartArray* start_array = _space_info[space_id].start_array();
3278 3277 MoveAndUpdateClosure closure(bitmap, cm, start_array, dest_addr, words);
3279 3278
3280 3279 ParMarkBitMap::IterationStatus status;
3281 3280 status = bitmap->iterate(&closure, dest_addr, end_addr);
3282 3281 assert(status == ParMarkBitMap::full, "iteration not complete");
3283 3282 assert(bitmap->find_obj_beg(closure.source(), end_addr) == end_addr,
3284 3283 "live objects skipped because closure is full");
3285 3284 }
3286 3285 }
3287 3286
3288 3287 jlong PSParallelCompact::millis_since_last_gc() {
3289 3288 // We need a monotonically non-deccreasing time in ms but
3290 3289 // os::javaTimeMillis() does not guarantee monotonicity.
3291 3290 jlong now = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
3292 3291 jlong ret_val = now - _time_of_last_gc;
3293 3292 // XXX See note in genCollectedHeap::millis_since_last_gc().
3294 3293 if (ret_val < 0) {
3295 3294 NOT_PRODUCT(warning("time warp: "INT64_FORMAT, ret_val);)
3296 3295 return 0;
3297 3296 }
3298 3297 return ret_val;
3299 3298 }
3300 3299
3301 3300 void PSParallelCompact::reset_millis_since_last_gc() {
3302 3301 // We need a monotonically non-deccreasing time in ms but
3303 3302 // os::javaTimeMillis() does not guarantee monotonicity.
3304 3303 _time_of_last_gc = os::javaTimeNanos() / NANOSECS_PER_MILLISEC;
3305 3304 }
3306 3305
3307 3306 ParMarkBitMap::IterationStatus MoveAndUpdateClosure::copy_until_full()
3308 3307 {
3309 3308 if (source() != destination()) {
3310 3309 DEBUG_ONLY(PSParallelCompact::check_new_location(source(), destination());)
3311 3310 Copy::aligned_conjoint_words(source(), destination(), words_remaining());
3312 3311 }
3313 3312 update_state(words_remaining());
3314 3313 assert(is_full(), "sanity");
3315 3314 return ParMarkBitMap::full;
3316 3315 }
3317 3316
3318 3317 void MoveAndUpdateClosure::copy_partial_obj()
3319 3318 {
3320 3319 size_t words = words_remaining();
3321 3320
3322 3321 HeapWord* const range_end = MIN2(source() + words, bitmap()->region_end());
3323 3322 HeapWord* const end_addr = bitmap()->find_obj_end(source(), range_end);
3324 3323 if (end_addr < range_end) {
3325 3324 words = bitmap()->obj_size(source(), end_addr);
3326 3325 }
3327 3326
3328 3327 // This test is necessary; if omitted, the pointer updates to a partial object
3329 3328 // that crosses the dense prefix boundary could be overwritten.
3330 3329 if (source() != destination()) {
3331 3330 DEBUG_ONLY(PSParallelCompact::check_new_location(source(), destination());)
3332 3331 Copy::aligned_conjoint_words(source(), destination(), words);
3333 3332 }
3334 3333 update_state(words);
3335 3334 }
3336 3335
3337 3336 ParMarkBitMapClosure::IterationStatus
3338 3337 MoveAndUpdateClosure::do_addr(HeapWord* addr, size_t words) {
3339 3338 assert(destination() != NULL, "sanity");
3340 3339 assert(bitmap()->obj_size(addr) == words, "bad size");
3341 3340
3342 3341 _source = addr;
3343 3342 assert(PSParallelCompact::summary_data().calc_new_pointer(source()) ==
3344 3343 destination(), "wrong destination");
3345 3344
3346 3345 if (words > words_remaining()) {
3347 3346 return ParMarkBitMap::would_overflow;
3348 3347 }
3349 3348
3350 3349 // The start_array must be updated even if the object is not moving.
3351 3350 if (_start_array != NULL) {
3352 3351 _start_array->allocate_block(destination());
3353 3352 }
3354 3353
3355 3354 if (destination() != source()) {
3356 3355 DEBUG_ONLY(PSParallelCompact::check_new_location(source(), destination());)
3357 3356 Copy::aligned_conjoint_words(source(), destination(), words);
3358 3357 }
3359 3358
3360 3359 oop moved_oop = (oop) destination();
3361 3360 moved_oop->update_contents(compaction_manager());
3362 3361 assert(moved_oop->is_oop_or_null(), "Object should be whole at this point");
3363 3362
3364 3363 update_state(words);
3365 3364 assert(destination() == (HeapWord*)moved_oop + moved_oop->size(), "sanity");
3366 3365 return is_full() ? ParMarkBitMap::full : ParMarkBitMap::incomplete;
3367 3366 }
3368 3367
3369 3368 UpdateOnlyClosure::UpdateOnlyClosure(ParMarkBitMap* mbm,
3370 3369 ParCompactionManager* cm,
3371 3370 PSParallelCompact::SpaceId space_id) :
3372 3371 ParMarkBitMapClosure(mbm, cm),
3373 3372 _space_id(space_id),
3374 3373 _start_array(PSParallelCompact::start_array(space_id))
3375 3374 {
3376 3375 }
3377 3376
3378 3377 // Updates the references in the object to their new values.
3379 3378 ParMarkBitMapClosure::IterationStatus
3380 3379 UpdateOnlyClosure::do_addr(HeapWord* addr, size_t words) {
3381 3380 do_addr(addr);
3382 3381 return ParMarkBitMap::incomplete;
3383 3382 }
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