Print this page
rev 2691 : [mq]: g1-reference-processing
| Split |
Close |
| Expand all |
| Collapse all |
--- old/src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp
+++ new/src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp
1 1 /*
2 2 * Copyright (c) 2001, 2011, 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/generationSizer.hpp"
30 30 #include "gc_implementation/parallelScavenge/parallelScavengeHeap.hpp"
31 31 #include "gc_implementation/parallelScavenge/psAdaptiveSizePolicy.hpp"
32 32 #include "gc_implementation/parallelScavenge/psMarkSweep.hpp"
33 33 #include "gc_implementation/parallelScavenge/psMarkSweepDecorator.hpp"
34 34 #include "gc_implementation/parallelScavenge/psOldGen.hpp"
35 35 #include "gc_implementation/parallelScavenge/psPermGen.hpp"
36 36 #include "gc_implementation/parallelScavenge/psScavenge.hpp"
37 37 #include "gc_implementation/parallelScavenge/psYoungGen.hpp"
38 38 #include "gc_implementation/shared/isGCActiveMark.hpp"
39 39 #include "gc_implementation/shared/spaceDecorator.hpp"
40 40 #include "gc_interface/gcCause.hpp"
41 41 #include "memory/gcLocker.inline.hpp"
42 42 #include "memory/referencePolicy.hpp"
43 43 #include "memory/referenceProcessor.hpp"
44 44 #include "oops/oop.inline.hpp"
45 45 #include "runtime/biasedLocking.hpp"
46 46 #include "runtime/fprofiler.hpp"
47 47 #include "runtime/safepoint.hpp"
48 48 #include "runtime/vmThread.hpp"
49 49 #include "services/management.hpp"
50 50 #include "services/memoryService.hpp"
51 51 #include "utilities/events.hpp"
52 52 #include "utilities/stack.inline.hpp"
53 53
54 54 elapsedTimer PSMarkSweep::_accumulated_time;
55 55 unsigned int PSMarkSweep::_total_invocations = 0;
56 56 jlong PSMarkSweep::_time_of_last_gc = 0;
57 57 CollectorCounters* PSMarkSweep::_counters = NULL;
58 58
59 59 void PSMarkSweep::initialize() {
60 60 MemRegion mr = Universe::heap()->reserved_region();
61 61 _ref_processor = new ReferenceProcessor(mr); // a vanilla ref proc
62 62 _counters = new CollectorCounters("PSMarkSweep", 1);
63 63 }
64 64
65 65 // This method contains all heap specific policy for invoking mark sweep.
66 66 // PSMarkSweep::invoke_no_policy() will only attempt to mark-sweep-compact
67 67 // the heap. It will do nothing further. If we need to bail out for policy
68 68 // reasons, scavenge before full gc, or any other specialized behavior, it
69 69 // needs to be added here.
70 70 //
71 71 // Note that this method should only be called from the vm_thread while
72 72 // at a safepoint!
73 73 //
74 74 // Note that the all_soft_refs_clear flag in the collector policy
75 75 // may be true because this method can be called without intervening
76 76 // activity. For example when the heap space is tight and full measure
77 77 // are being taken to free space.
78 78
79 79 void PSMarkSweep::invoke(bool maximum_heap_compaction) {
80 80 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
81 81 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
82 82 assert(!Universe::heap()->is_gc_active(), "not reentrant");
83 83
84 84 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
85 85 GCCause::Cause gc_cause = heap->gc_cause();
86 86 PSAdaptiveSizePolicy* policy = heap->size_policy();
87 87 IsGCActiveMark mark;
88 88
89 89 if (ScavengeBeforeFullGC) {
90 90 PSScavenge::invoke_no_policy();
91 91 }
92 92
93 93 const bool clear_all_soft_refs =
94 94 heap->collector_policy()->should_clear_all_soft_refs();
95 95
96 96 int count = (maximum_heap_compaction)?1:MarkSweepAlwaysCompactCount;
97 97 IntFlagSetting flag_setting(MarkSweepAlwaysCompactCount, count);
98 98 PSMarkSweep::invoke_no_policy(clear_all_soft_refs || maximum_heap_compaction);
99 99 }
100 100
101 101 // This method contains no policy. You should probably
102 102 // be calling invoke() instead.
103 103 void PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) {
104 104 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
105 105 assert(ref_processor() != NULL, "Sanity");
106 106
107 107 if (GC_locker::check_active_before_gc()) {
108 108 return;
109 109 }
110 110
111 111 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
112 112 GCCause::Cause gc_cause = heap->gc_cause();
113 113 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
114 114 PSAdaptiveSizePolicy* size_policy = heap->size_policy();
115 115
116 116 // The scope of casr should end after code that can change
117 117 // CollectorPolicy::_should_clear_all_soft_refs.
118 118 ClearedAllSoftRefs casr(clear_all_softrefs, heap->collector_policy());
119 119
120 120 PSYoungGen* young_gen = heap->young_gen();
121 121 PSOldGen* old_gen = heap->old_gen();
122 122 PSPermGen* perm_gen = heap->perm_gen();
123 123
124 124 // Increment the invocation count
125 125 heap->increment_total_collections(true /* full */);
126 126
127 127 // Save information needed to minimize mangling
128 128 heap->record_gen_tops_before_GC();
129 129
130 130 // We need to track unique mark sweep invocations as well.
131 131 _total_invocations++;
132 132
133 133 AdaptiveSizePolicyOutput(size_policy, heap->total_collections());
134 134
135 135 if (PrintHeapAtGC) {
136 136 Universe::print_heap_before_gc();
137 137 }
138 138
139 139 // Fill in TLABs
140 140 heap->accumulate_statistics_all_tlabs();
141 141 heap->ensure_parsability(true); // retire TLABs
142 142
143 143 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) {
144 144 HandleMark hm; // Discard invalid handles created during verification
145 145 gclog_or_tty->print(" VerifyBeforeGC:");
146 146 Universe::verify(true);
147 147 }
148 148
149 149 // Verify object start arrays
150 150 if (VerifyObjectStartArray &&
151 151 VerifyBeforeGC) {
152 152 old_gen->verify_object_start_array();
153 153 perm_gen->verify_object_start_array();
154 154 }
155 155
156 156 heap->pre_full_gc_dump();
157 157
158 158 // Filled in below to track the state of the young gen after the collection.
159 159 bool eden_empty;
160 160 bool survivors_empty;
161 161 bool young_gen_empty;
162 162
163 163 {
164 164 HandleMark hm;
165 165 const bool is_system_gc = gc_cause == GCCause::_java_lang_system_gc;
166 166 // This is useful for debugging but don't change the output the
167 167 // the customer sees.
168 168 const char* gc_cause_str = "Full GC";
169 169 if (is_system_gc && PrintGCDetails) {
170 170 gc_cause_str = "Full GC (System)";
171 171 }
172 172 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
173 173 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
174 174 TraceTime t1(gc_cause_str, PrintGC, !PrintGCDetails, gclog_or_tty);
175 175 TraceCollectorStats tcs(counters());
176 176 TraceMemoryManagerStats tms(true /* Full GC */,gc_cause);
177 177
178 178 if (TraceGen1Time) accumulated_time()->start();
179 179
180 180 // Let the size policy know we're starting
181 181 size_policy->major_collection_begin();
182 182
183 183 // When collecting the permanent generation methodOops may be moving,
184 184 // so we either have to flush all bcp data or convert it into bci.
185 185 CodeCache::gc_prologue();
186 186 Threads::gc_prologue();
187 187 BiasedLocking::preserve_marks();
188 188
189 189 // Capture heap size before collection for printing.
190 190 size_t prev_used = heap->used();
|
↓ open down ↓ |
190 lines elided |
↑ open up ↑ |
191 191
192 192 // Capture perm gen size before collection for sizing.
193 193 size_t perm_gen_prev_used = perm_gen->used_in_bytes();
194 194
195 195 // For PrintGCDetails
196 196 size_t old_gen_prev_used = old_gen->used_in_bytes();
197 197 size_t young_gen_prev_used = young_gen->used_in_bytes();
198 198
199 199 allocate_stacks();
200 200
201 - NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
202 201 COMPILER2_PRESENT(DerivedPointerTable::clear());
203 202
204 - ref_processor()->enable_discovery();
203 + ref_processor()->enable_discovery(true /*verify_disabled*/, true /*verify_no_refs*/);
205 204 ref_processor()->setup_policy(clear_all_softrefs);
206 205
207 206 mark_sweep_phase1(clear_all_softrefs);
208 207
209 208 mark_sweep_phase2();
210 209
211 210 // Don't add any more derived pointers during phase3
212 211 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity"));
213 212 COMPILER2_PRESENT(DerivedPointerTable::set_active(false));
214 213
215 214 mark_sweep_phase3();
216 215
217 216 mark_sweep_phase4();
218 217
219 218 restore_marks();
220 219
221 220 deallocate_stacks();
222 221
223 222 if (ZapUnusedHeapArea) {
224 223 // Do a complete mangle (top to end) because the usage for
225 224 // scratch does not maintain a top pointer.
226 225 young_gen->to_space()->mangle_unused_area_complete();
227 226 }
228 227
229 228 eden_empty = young_gen->eden_space()->is_empty();
230 229 if (!eden_empty) {
231 230 eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen);
232 231 }
233 232
234 233 // Update heap occupancy information which is used as
235 234 // input to soft ref clearing policy at the next gc.
236 235 Universe::update_heap_info_at_gc();
237 236
238 237 survivors_empty = young_gen->from_space()->is_empty() &&
239 238 young_gen->to_space()->is_empty();
240 239 young_gen_empty = eden_empty && survivors_empty;
241 240
242 241 BarrierSet* bs = heap->barrier_set();
243 242 if (bs->is_a(BarrierSet::ModRef)) {
244 243 ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs;
245 244 MemRegion old_mr = heap->old_gen()->reserved();
246 245 MemRegion perm_mr = heap->perm_gen()->reserved();
247 246 assert(perm_mr.end() <= old_mr.start(), "Generations out of order");
248 247
249 248 if (young_gen_empty) {
250 249 modBS->clear(MemRegion(perm_mr.start(), old_mr.end()));
251 250 } else {
252 251 modBS->invalidate(MemRegion(perm_mr.start(), old_mr.end()));
253 252 }
254 253 }
255 254
256 255 BiasedLocking::restore_marks();
257 256 Threads::gc_epilogue();
258 257 CodeCache::gc_epilogue();
259 258 JvmtiExport::gc_epilogue();
260 259
261 260 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
262 261
263 262 ref_processor()->enqueue_discovered_references(NULL);
264 263
265 264 // Update time of last GC
266 265 reset_millis_since_last_gc();
267 266
268 267 // Let the size policy know we're done
269 268 size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause);
270 269
271 270 if (UseAdaptiveSizePolicy) {
272 271
273 272 if (PrintAdaptiveSizePolicy) {
274 273 gclog_or_tty->print("AdaptiveSizeStart: ");
275 274 gclog_or_tty->stamp();
276 275 gclog_or_tty->print_cr(" collection: %d ",
277 276 heap->total_collections());
278 277 if (Verbose) {
279 278 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d"
280 279 " perm_gen_capacity: %d ",
281 280 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(),
282 281 perm_gen->capacity_in_bytes());
283 282 }
284 283 }
285 284
286 285 // Don't check if the size_policy is ready here. Let
287 286 // the size_policy check that internally.
288 287 if (UseAdaptiveGenerationSizePolicyAtMajorCollection &&
289 288 ((gc_cause != GCCause::_java_lang_system_gc) ||
290 289 UseAdaptiveSizePolicyWithSystemGC)) {
291 290 // Calculate optimal free space amounts
292 291 assert(young_gen->max_size() >
293 292 young_gen->from_space()->capacity_in_bytes() +
294 293 young_gen->to_space()->capacity_in_bytes(),
295 294 "Sizes of space in young gen are out-of-bounds");
296 295 size_t max_eden_size = young_gen->max_size() -
297 296 young_gen->from_space()->capacity_in_bytes() -
298 297 young_gen->to_space()->capacity_in_bytes();
299 298 size_policy->compute_generation_free_space(young_gen->used_in_bytes(),
300 299 young_gen->eden_space()->used_in_bytes(),
301 300 old_gen->used_in_bytes(),
302 301 perm_gen->used_in_bytes(),
303 302 young_gen->eden_space()->capacity_in_bytes(),
304 303 old_gen->max_gen_size(),
305 304 max_eden_size,
306 305 true /* full gc*/,
307 306 gc_cause,
308 307 heap->collector_policy());
309 308
310 309 heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes());
311 310
312 311 // Don't resize the young generation at an major collection. A
313 312 // desired young generation size may have been calculated but
314 313 // resizing the young generation complicates the code because the
315 314 // resizing of the old generation may have moved the boundary
316 315 // between the young generation and the old generation. Let the
317 316 // young generation resizing happen at the minor collections.
318 317 }
319 318 if (PrintAdaptiveSizePolicy) {
320 319 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ",
321 320 heap->total_collections());
322 321 }
323 322 }
324 323
325 324 if (UsePerfData) {
326 325 heap->gc_policy_counters()->update_counters();
327 326 heap->gc_policy_counters()->update_old_capacity(
328 327 old_gen->capacity_in_bytes());
329 328 heap->gc_policy_counters()->update_young_capacity(
330 329 young_gen->capacity_in_bytes());
331 330 }
332 331
333 332 heap->resize_all_tlabs();
334 333
335 334 // We collected the perm gen, so we'll resize it here.
336 335 perm_gen->compute_new_size(perm_gen_prev_used);
337 336
338 337 if (TraceGen1Time) accumulated_time()->stop();
339 338
340 339 if (PrintGC) {
341 340 if (PrintGCDetails) {
342 341 // Don't print a GC timestamp here. This is after the GC so
343 342 // would be confusing.
344 343 young_gen->print_used_change(young_gen_prev_used);
345 344 old_gen->print_used_change(old_gen_prev_used);
346 345 }
347 346 heap->print_heap_change(prev_used);
348 347 // Do perm gen after heap becase prev_used does
349 348 // not include the perm gen (done this way in the other
350 349 // collectors).
351 350 if (PrintGCDetails) {
352 351 perm_gen->print_used_change(perm_gen_prev_used);
353 352 }
354 353 }
355 354
356 355 // Track memory usage and detect low memory
357 356 MemoryService::track_memory_usage();
358 357 heap->update_counters();
359 358 }
360 359
361 360 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) {
362 361 HandleMark hm; // Discard invalid handles created during verification
363 362 gclog_or_tty->print(" VerifyAfterGC:");
364 363 Universe::verify(false);
365 364 }
366 365
367 366 // Re-verify object start arrays
368 367 if (VerifyObjectStartArray &&
369 368 VerifyAfterGC) {
370 369 old_gen->verify_object_start_array();
371 370 perm_gen->verify_object_start_array();
372 371 }
373 372
374 373 if (ZapUnusedHeapArea) {
375 374 old_gen->object_space()->check_mangled_unused_area_complete();
376 375 perm_gen->object_space()->check_mangled_unused_area_complete();
377 376 }
378 377
379 378 NOT_PRODUCT(ref_processor()->verify_no_references_recorded());
380 379
381 380 if (PrintHeapAtGC) {
382 381 Universe::print_heap_after_gc();
383 382 }
384 383
385 384 heap->post_full_gc_dump();
386 385
387 386 #ifdef TRACESPINNING
388 387 ParallelTaskTerminator::print_termination_counts();
389 388 #endif
390 389 }
391 390
392 391 bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy,
393 392 PSYoungGen* young_gen,
394 393 PSOldGen* old_gen) {
395 394 MutableSpace* const eden_space = young_gen->eden_space();
396 395 assert(!eden_space->is_empty(), "eden must be non-empty");
397 396 assert(young_gen->virtual_space()->alignment() ==
398 397 old_gen->virtual_space()->alignment(), "alignments do not match");
399 398
400 399 if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) {
401 400 return false;
402 401 }
403 402
404 403 // Both generations must be completely committed.
405 404 if (young_gen->virtual_space()->uncommitted_size() != 0) {
406 405 return false;
407 406 }
408 407 if (old_gen->virtual_space()->uncommitted_size() != 0) {
409 408 return false;
410 409 }
411 410
412 411 // Figure out how much to take from eden. Include the average amount promoted
413 412 // in the total; otherwise the next young gen GC will simply bail out to a
414 413 // full GC.
415 414 const size_t alignment = old_gen->virtual_space()->alignment();
416 415 const size_t eden_used = eden_space->used_in_bytes();
417 416 const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average();
418 417 const size_t absorb_size = align_size_up(eden_used + promoted, alignment);
419 418 const size_t eden_capacity = eden_space->capacity_in_bytes();
420 419
421 420 if (absorb_size >= eden_capacity) {
422 421 return false; // Must leave some space in eden.
423 422 }
424 423
425 424 const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size;
426 425 if (new_young_size < young_gen->min_gen_size()) {
427 426 return false; // Respect young gen minimum size.
428 427 }
429 428
430 429 if (TraceAdaptiveGCBoundary && Verbose) {
431 430 gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: "
432 431 "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K "
433 432 "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K "
434 433 "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ",
435 434 absorb_size / K,
436 435 eden_capacity / K, (eden_capacity - absorb_size) / K,
437 436 young_gen->from_space()->used_in_bytes() / K,
438 437 young_gen->to_space()->used_in_bytes() / K,
439 438 young_gen->capacity_in_bytes() / K, new_young_size / K);
440 439 }
441 440
442 441 // Fill the unused part of the old gen.
443 442 MutableSpace* const old_space = old_gen->object_space();
444 443 HeapWord* const unused_start = old_space->top();
445 444 size_t const unused_words = pointer_delta(old_space->end(), unused_start);
446 445
447 446 if (unused_words > 0) {
448 447 if (unused_words < CollectedHeap::min_fill_size()) {
449 448 return false; // If the old gen cannot be filled, must give up.
450 449 }
451 450 CollectedHeap::fill_with_objects(unused_start, unused_words);
452 451 }
453 452
454 453 // Take the live data from eden and set both top and end in the old gen to
455 454 // eden top. (Need to set end because reset_after_change() mangles the region
456 455 // from end to virtual_space->high() in debug builds).
457 456 HeapWord* const new_top = eden_space->top();
458 457 old_gen->virtual_space()->expand_into(young_gen->virtual_space(),
459 458 absorb_size);
460 459 young_gen->reset_after_change();
461 460 old_space->set_top(new_top);
462 461 old_space->set_end(new_top);
463 462 old_gen->reset_after_change();
464 463
465 464 // Update the object start array for the filler object and the data from eden.
466 465 ObjectStartArray* const start_array = old_gen->start_array();
467 466 for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) {
468 467 start_array->allocate_block(p);
469 468 }
470 469
471 470 // Could update the promoted average here, but it is not typically updated at
472 471 // full GCs and the value to use is unclear. Something like
473 472 //
474 473 // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc.
475 474
476 475 size_policy->set_bytes_absorbed_from_eden(absorb_size);
477 476 return true;
478 477 }
479 478
480 479 void PSMarkSweep::allocate_stacks() {
481 480 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
482 481 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
483 482
484 483 PSYoungGen* young_gen = heap->young_gen();
485 484
486 485 MutableSpace* to_space = young_gen->to_space();
487 486 _preserved_marks = (PreservedMark*)to_space->top();
488 487 _preserved_count = 0;
489 488
490 489 // We want to calculate the size in bytes first.
491 490 _preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte));
492 491 // Now divide by the size of a PreservedMark
493 492 _preserved_count_max /= sizeof(PreservedMark);
494 493 }
495 494
496 495
497 496 void PSMarkSweep::deallocate_stacks() {
498 497 _preserved_mark_stack.clear(true);
499 498 _preserved_oop_stack.clear(true);
500 499 _marking_stack.clear();
501 500 _objarray_stack.clear(true);
502 501 _revisit_klass_stack.clear(true);
503 502 _revisit_mdo_stack.clear(true);
504 503 }
505 504
506 505 void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) {
507 506 // Recursively traverse all live objects and mark them
508 507 EventMark m("1 mark object");
509 508 TraceTime tm("phase 1", PrintGCDetails && Verbose, true, gclog_or_tty);
510 509 trace(" 1");
511 510
512 511 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
513 512 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
514 513
515 514 // General strong roots.
516 515 {
517 516 ParallelScavengeHeap::ParStrongRootsScope psrs;
518 517 Universe::oops_do(mark_and_push_closure());
519 518 JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles
520 519 CodeBlobToOopClosure each_active_code_blob(mark_and_push_closure(), /*do_marking=*/ true);
521 520 Threads::oops_do(mark_and_push_closure(), &each_active_code_blob);
522 521 ObjectSynchronizer::oops_do(mark_and_push_closure());
523 522 FlatProfiler::oops_do(mark_and_push_closure());
524 523 Management::oops_do(mark_and_push_closure());
525 524 JvmtiExport::oops_do(mark_and_push_closure());
526 525 SystemDictionary::always_strong_oops_do(mark_and_push_closure());
527 526 // Do not treat nmethods as strong roots for mark/sweep, since we can unload them.
528 527 //CodeCache::scavenge_root_nmethods_do(CodeBlobToOopClosure(mark_and_push_closure()));
529 528 }
530 529
531 530 // Flush marking stack.
532 531 follow_stack();
533 532
534 533 // Process reference objects found during marking
535 534 {
536 535 ref_processor()->setup_policy(clear_all_softrefs);
537 536 ref_processor()->process_discovered_references(
538 537 is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL);
539 538 }
540 539
541 540 // Follow system dictionary roots and unload classes
542 541 bool purged_class = SystemDictionary::do_unloading(is_alive_closure());
543 542
544 543 // Follow code cache roots
545 544 CodeCache::do_unloading(is_alive_closure(), mark_and_push_closure(),
546 545 purged_class);
547 546 follow_stack(); // Flush marking stack
548 547
549 548 // Update subklass/sibling/implementor links of live klasses
550 549 follow_weak_klass_links();
551 550 assert(_marking_stack.is_empty(), "just drained");
552 551
553 552 // Visit memoized mdo's and clear unmarked weak refs
554 553 follow_mdo_weak_refs();
555 554 assert(_marking_stack.is_empty(), "just drained");
556 555
557 556 // Visit interned string tables and delete unmarked oops
558 557 StringTable::unlink(is_alive_closure());
559 558 // Clean up unreferenced symbols in symbol table.
560 559 SymbolTable::unlink();
561 560
562 561 assert(_marking_stack.is_empty(), "stack should be empty by now");
563 562 }
564 563
565 564
566 565 void PSMarkSweep::mark_sweep_phase2() {
567 566 EventMark m("2 compute new addresses");
568 567 TraceTime tm("phase 2", PrintGCDetails && Verbose, true, gclog_or_tty);
569 568 trace("2");
570 569
571 570 // Now all live objects are marked, compute the new object addresses.
572 571
573 572 // It is imperative that we traverse perm_gen LAST. If dead space is
574 573 // allowed a range of dead object may get overwritten by a dead int
575 574 // array. If perm_gen is not traversed last a klassOop may get
576 575 // overwritten. This is fine since it is dead, but if the class has dead
577 576 // instances we have to skip them, and in order to find their size we
578 577 // need the klassOop!
579 578 //
580 579 // It is not required that we traverse spaces in the same order in
581 580 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops
582 581 // tracking expects us to do so. See comment under phase4.
583 582
584 583 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
585 584 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
586 585
587 586 PSOldGen* old_gen = heap->old_gen();
588 587 PSPermGen* perm_gen = heap->perm_gen();
589 588
590 589 // Begin compacting into the old gen
591 590 PSMarkSweepDecorator::set_destination_decorator_tenured();
592 591
593 592 // This will also compact the young gen spaces.
594 593 old_gen->precompact();
595 594
596 595 // Compact the perm gen into the perm gen
597 596 PSMarkSweepDecorator::set_destination_decorator_perm_gen();
598 597
599 598 perm_gen->precompact();
600 599 }
601 600
602 601 // This should be moved to the shared markSweep code!
603 602 class PSAlwaysTrueClosure: public BoolObjectClosure {
604 603 public:
605 604 void do_object(oop p) { ShouldNotReachHere(); }
606 605 bool do_object_b(oop p) { return true; }
607 606 };
608 607 static PSAlwaysTrueClosure always_true;
609 608
610 609 void PSMarkSweep::mark_sweep_phase3() {
611 610 // Adjust the pointers to reflect the new locations
612 611 EventMark m("3 adjust pointers");
613 612 TraceTime tm("phase 3", PrintGCDetails && Verbose, true, gclog_or_tty);
614 613 trace("3");
615 614
616 615 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
617 616 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
618 617
619 618 PSYoungGen* young_gen = heap->young_gen();
620 619 PSOldGen* old_gen = heap->old_gen();
621 620 PSPermGen* perm_gen = heap->perm_gen();
622 621
623 622 // General strong roots.
624 623 Universe::oops_do(adjust_root_pointer_closure());
625 624 JNIHandles::oops_do(adjust_root_pointer_closure()); // Global (strong) JNI handles
626 625 Threads::oops_do(adjust_root_pointer_closure(), NULL);
627 626 ObjectSynchronizer::oops_do(adjust_root_pointer_closure());
628 627 FlatProfiler::oops_do(adjust_root_pointer_closure());
629 628 Management::oops_do(adjust_root_pointer_closure());
630 629 JvmtiExport::oops_do(adjust_root_pointer_closure());
631 630 // SO_AllClasses
632 631 SystemDictionary::oops_do(adjust_root_pointer_closure());
633 632 //CodeCache::scavenge_root_nmethods_oops_do(adjust_root_pointer_closure());
634 633
635 634 // Now adjust pointers in remaining weak roots. (All of which should
636 635 // have been cleared if they pointed to non-surviving objects.)
637 636 // Global (weak) JNI handles
638 637 JNIHandles::weak_oops_do(&always_true, adjust_root_pointer_closure());
639 638
640 639 CodeCache::oops_do(adjust_pointer_closure());
641 640 StringTable::oops_do(adjust_root_pointer_closure());
642 641 ref_processor()->weak_oops_do(adjust_root_pointer_closure());
643 642 PSScavenge::reference_processor()->weak_oops_do(adjust_root_pointer_closure());
644 643
645 644 adjust_marks();
646 645
647 646 young_gen->adjust_pointers();
648 647 old_gen->adjust_pointers();
649 648 perm_gen->adjust_pointers();
650 649 }
651 650
652 651 void PSMarkSweep::mark_sweep_phase4() {
653 652 EventMark m("4 compact heap");
654 653 TraceTime tm("phase 4", PrintGCDetails && Verbose, true, gclog_or_tty);
655 654 trace("4");
656 655
657 656 // All pointers are now adjusted, move objects accordingly
658 657
659 658 // It is imperative that we traverse perm_gen first in phase4. All
660 659 // classes must be allocated earlier than their instances, and traversing
661 660 // perm_gen first makes sure that all klassOops have moved to their new
662 661 // location before any instance does a dispatch through it's klass!
663 662 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap();
664 663 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity");
665 664
666 665 PSYoungGen* young_gen = heap->young_gen();
667 666 PSOldGen* old_gen = heap->old_gen();
668 667 PSPermGen* perm_gen = heap->perm_gen();
669 668
670 669 perm_gen->compact();
671 670 old_gen->compact();
672 671 young_gen->compact();
673 672 }
674 673
675 674 jlong PSMarkSweep::millis_since_last_gc() {
676 675 jlong ret_val = os::javaTimeMillis() - _time_of_last_gc;
677 676 // XXX See note in genCollectedHeap::millis_since_last_gc().
678 677 if (ret_val < 0) {
679 678 NOT_PRODUCT(warning("time warp: %d", ret_val);)
680 679 return 0;
681 680 }
682 681 return ret_val;
683 682 }
684 683
685 684 void PSMarkSweep::reset_millis_since_last_gc() {
686 685 _time_of_last_gc = os::javaTimeMillis();
687 686 }
|
↓ open down ↓ |
473 lines elided |
↑ open up ↑ |
XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX