Mercurial > hg > graal-compiler
annotate src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp @ 380:eb28cf662f56
Merge
author | trims |
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date | Tue, 07 Oct 2008 11:01:35 -0700 |
parents | a4b729f5b611 9ee9cf798b59 |
children | c96030fff130 |
rev | line source |
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0 | 1 /* |
337 | 2 * Copyright 2001-2008 Sun Microsystems, Inc. All Rights Reserved. |
0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
21 * have any questions. | |
22 * | |
23 */ | |
24 | |
25 #include "incls/_precompiled.incl" | |
26 #include "incls/_psMarkSweep.cpp.incl" | |
27 | |
28 elapsedTimer PSMarkSweep::_accumulated_time; | |
29 unsigned int PSMarkSweep::_total_invocations = 0; | |
30 jlong PSMarkSweep::_time_of_last_gc = 0; | |
31 CollectorCounters* PSMarkSweep::_counters = NULL; | |
32 | |
33 void PSMarkSweep::initialize() { | |
34 MemRegion mr = Universe::heap()->reserved_region(); | |
35 _ref_processor = new ReferenceProcessor(mr, | |
36 true, // atomic_discovery | |
37 false); // mt_discovery | |
374
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38 _counters = new CollectorCounters("PSMarkSweep", 1); |
0 | 39 } |
40 | |
41 // This method contains all heap specific policy for invoking mark sweep. | |
42 // PSMarkSweep::invoke_no_policy() will only attempt to mark-sweep-compact | |
43 // the heap. It will do nothing further. If we need to bail out for policy | |
44 // reasons, scavenge before full gc, or any other specialized behavior, it | |
45 // needs to be added here. | |
46 // | |
47 // Note that this method should only be called from the vm_thread while | |
48 // at a safepoint! | |
49 void PSMarkSweep::invoke(bool maximum_heap_compaction) { | |
50 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); | |
51 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); | |
52 assert(!Universe::heap()->is_gc_active(), "not reentrant"); | |
53 | |
54 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
55 GCCause::Cause gc_cause = heap->gc_cause(); | |
56 PSAdaptiveSizePolicy* policy = heap->size_policy(); | |
57 | |
58 // Before each allocation/collection attempt, find out from the | |
59 // policy object if GCs are, on the whole, taking too long. If so, | |
60 // bail out without attempting a collection. The exceptions are | |
61 // for explicitly requested GC's. | |
62 if (!policy->gc_time_limit_exceeded() || | |
63 GCCause::is_user_requested_gc(gc_cause) || | |
64 GCCause::is_serviceability_requested_gc(gc_cause)) { | |
65 IsGCActiveMark mark; | |
66 | |
67 if (ScavengeBeforeFullGC) { | |
68 PSScavenge::invoke_no_policy(); | |
69 } | |
70 | |
71 int count = (maximum_heap_compaction)?1:MarkSweepAlwaysCompactCount; | |
72 IntFlagSetting flag_setting(MarkSweepAlwaysCompactCount, count); | |
73 PSMarkSweep::invoke_no_policy(maximum_heap_compaction); | |
74 } | |
75 } | |
76 | |
77 // This method contains no policy. You should probably | |
78 // be calling invoke() instead. | |
79 void PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) { | |
80 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); | |
81 assert(ref_processor() != NULL, "Sanity"); | |
82 | |
83 if (GC_locker::check_active_before_gc()) { | |
84 return; | |
85 } | |
86 | |
87 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
88 GCCause::Cause gc_cause = heap->gc_cause(); | |
89 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
90 PSAdaptiveSizePolicy* size_policy = heap->size_policy(); | |
91 | |
92 PSYoungGen* young_gen = heap->young_gen(); | |
93 PSOldGen* old_gen = heap->old_gen(); | |
94 PSPermGen* perm_gen = heap->perm_gen(); | |
95 | |
96 // Increment the invocation count | |
97 heap->increment_total_collections(true /* full */); | |
98 | |
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99 // Save information needed to minimize mangling |
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100 heap->record_gen_tops_before_GC(); |
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101 |
0 | 102 // We need to track unique mark sweep invocations as well. |
103 _total_invocations++; | |
104 | |
105 AdaptiveSizePolicyOutput(size_policy, heap->total_collections()); | |
106 | |
107 if (PrintHeapAtGC) { | |
108 Universe::print_heap_before_gc(); | |
109 } | |
110 | |
111 // Fill in TLABs | |
112 heap->accumulate_statistics_all_tlabs(); | |
113 heap->ensure_parsability(true); // retire TLABs | |
114 | |
115 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) { | |
116 HandleMark hm; // Discard invalid handles created during verification | |
117 gclog_or_tty->print(" VerifyBeforeGC:"); | |
118 Universe::verify(true); | |
119 } | |
120 | |
121 // Verify object start arrays | |
122 if (VerifyObjectStartArray && | |
123 VerifyBeforeGC) { | |
124 old_gen->verify_object_start_array(); | |
125 perm_gen->verify_object_start_array(); | |
126 } | |
127 | |
128 // Filled in below to track the state of the young gen after the collection. | |
129 bool eden_empty; | |
130 bool survivors_empty; | |
131 bool young_gen_empty; | |
132 | |
133 { | |
134 HandleMark hm; | |
135 const bool is_system_gc = gc_cause == GCCause::_java_lang_system_gc; | |
136 // This is useful for debugging but don't change the output the | |
137 // the customer sees. | |
138 const char* gc_cause_str = "Full GC"; | |
139 if (is_system_gc && PrintGCDetails) { | |
140 gc_cause_str = "Full GC (System)"; | |
141 } | |
142 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); | |
143 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); | |
144 TraceTime t1(gc_cause_str, PrintGC, !PrintGCDetails, gclog_or_tty); | |
145 TraceCollectorStats tcs(counters()); | |
146 TraceMemoryManagerStats tms(true /* Full GC */); | |
147 | |
148 if (TraceGen1Time) accumulated_time()->start(); | |
149 | |
150 // Let the size policy know we're starting | |
151 size_policy->major_collection_begin(); | |
152 | |
153 // When collecting the permanent generation methodOops may be moving, | |
154 // so we either have to flush all bcp data or convert it into bci. | |
155 CodeCache::gc_prologue(); | |
156 Threads::gc_prologue(); | |
157 BiasedLocking::preserve_marks(); | |
158 | |
159 // Capture heap size before collection for printing. | |
160 size_t prev_used = heap->used(); | |
161 | |
162 // Capture perm gen size before collection for sizing. | |
163 size_t perm_gen_prev_used = perm_gen->used_in_bytes(); | |
164 | |
165 // For PrintGCDetails | |
166 size_t old_gen_prev_used = old_gen->used_in_bytes(); | |
167 size_t young_gen_prev_used = young_gen->used_in_bytes(); | |
168 | |
169 allocate_stacks(); | |
170 | |
171 NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); | |
172 COMPILER2_PRESENT(DerivedPointerTable::clear()); | |
173 | |
174 ref_processor()->enable_discovery(); | |
175 | |
176 mark_sweep_phase1(clear_all_softrefs); | |
177 | |
178 mark_sweep_phase2(); | |
179 | |
180 // Don't add any more derived pointers during phase3 | |
181 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity")); | |
182 COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); | |
183 | |
184 mark_sweep_phase3(); | |
185 | |
186 mark_sweep_phase4(); | |
187 | |
188 restore_marks(); | |
189 | |
190 deallocate_stacks(); | |
191 | |
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192 if (ZapUnusedHeapArea) { |
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193 // Do a complete mangle (top to end) because the usage for |
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194 // scratch does not maintain a top pointer. |
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195 young_gen->to_space()->mangle_unused_area_complete(); |
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196 } |
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197 |
0 | 198 eden_empty = young_gen->eden_space()->is_empty(); |
199 if (!eden_empty) { | |
200 eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen); | |
201 } | |
202 | |
203 // Update heap occupancy information which is used as | |
204 // input to soft ref clearing policy at the next gc. | |
205 Universe::update_heap_info_at_gc(); | |
206 | |
207 survivors_empty = young_gen->from_space()->is_empty() && | |
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208 young_gen->to_space()->is_empty(); |
0 | 209 young_gen_empty = eden_empty && survivors_empty; |
210 | |
211 BarrierSet* bs = heap->barrier_set(); | |
212 if (bs->is_a(BarrierSet::ModRef)) { | |
213 ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs; | |
214 MemRegion old_mr = heap->old_gen()->reserved(); | |
215 MemRegion perm_mr = heap->perm_gen()->reserved(); | |
216 assert(perm_mr.end() <= old_mr.start(), "Generations out of order"); | |
217 | |
218 if (young_gen_empty) { | |
219 modBS->clear(MemRegion(perm_mr.start(), old_mr.end())); | |
220 } else { | |
221 modBS->invalidate(MemRegion(perm_mr.start(), old_mr.end())); | |
222 } | |
223 } | |
224 | |
225 BiasedLocking::restore_marks(); | |
226 Threads::gc_epilogue(); | |
227 CodeCache::gc_epilogue(); | |
228 | |
229 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); | |
230 | |
231 ref_processor()->enqueue_discovered_references(NULL); | |
232 | |
233 // Update time of last GC | |
234 reset_millis_since_last_gc(); | |
235 | |
236 // Let the size policy know we're done | |
237 size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause); | |
238 | |
239 if (UseAdaptiveSizePolicy) { | |
240 | |
241 if (PrintAdaptiveSizePolicy) { | |
242 gclog_or_tty->print("AdaptiveSizeStart: "); | |
243 gclog_or_tty->stamp(); | |
244 gclog_or_tty->print_cr(" collection: %d ", | |
245 heap->total_collections()); | |
246 if (Verbose) { | |
247 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d" | |
248 " perm_gen_capacity: %d ", | |
249 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(), | |
250 perm_gen->capacity_in_bytes()); | |
251 } | |
252 } | |
253 | |
254 // Don't check if the size_policy is ready here. Let | |
255 // the size_policy check that internally. | |
256 if (UseAdaptiveGenerationSizePolicyAtMajorCollection && | |
257 ((gc_cause != GCCause::_java_lang_system_gc) || | |
258 UseAdaptiveSizePolicyWithSystemGC)) { | |
259 // Calculate optimal free space amounts | |
260 assert(young_gen->max_size() > | |
261 young_gen->from_space()->capacity_in_bytes() + | |
262 young_gen->to_space()->capacity_in_bytes(), | |
263 "Sizes of space in young gen are out-of-bounds"); | |
264 size_t max_eden_size = young_gen->max_size() - | |
265 young_gen->from_space()->capacity_in_bytes() - | |
266 young_gen->to_space()->capacity_in_bytes(); | |
267 size_policy->compute_generation_free_space(young_gen->used_in_bytes(), | |
268 young_gen->eden_space()->used_in_bytes(), | |
269 old_gen->used_in_bytes(), | |
270 perm_gen->used_in_bytes(), | |
271 young_gen->eden_space()->capacity_in_bytes(), | |
272 old_gen->max_gen_size(), | |
273 max_eden_size, | |
274 true /* full gc*/, | |
275 gc_cause); | |
276 | |
277 heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes()); | |
278 | |
279 // Don't resize the young generation at an major collection. A | |
280 // desired young generation size may have been calculated but | |
281 // resizing the young generation complicates the code because the | |
282 // resizing of the old generation may have moved the boundary | |
283 // between the young generation and the old generation. Let the | |
284 // young generation resizing happen at the minor collections. | |
285 } | |
286 if (PrintAdaptiveSizePolicy) { | |
287 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ", | |
288 heap->total_collections()); | |
289 } | |
290 } | |
291 | |
292 if (UsePerfData) { | |
293 heap->gc_policy_counters()->update_counters(); | |
294 heap->gc_policy_counters()->update_old_capacity( | |
295 old_gen->capacity_in_bytes()); | |
296 heap->gc_policy_counters()->update_young_capacity( | |
297 young_gen->capacity_in_bytes()); | |
298 } | |
299 | |
300 heap->resize_all_tlabs(); | |
301 | |
302 // We collected the perm gen, so we'll resize it here. | |
303 perm_gen->compute_new_size(perm_gen_prev_used); | |
304 | |
305 if (TraceGen1Time) accumulated_time()->stop(); | |
306 | |
307 if (PrintGC) { | |
308 if (PrintGCDetails) { | |
309 // Don't print a GC timestamp here. This is after the GC so | |
310 // would be confusing. | |
311 young_gen->print_used_change(young_gen_prev_used); | |
312 old_gen->print_used_change(old_gen_prev_used); | |
313 } | |
314 heap->print_heap_change(prev_used); | |
315 // Do perm gen after heap becase prev_used does | |
316 // not include the perm gen (done this way in the other | |
317 // collectors). | |
318 if (PrintGCDetails) { | |
319 perm_gen->print_used_change(perm_gen_prev_used); | |
320 } | |
321 } | |
322 | |
323 // Track memory usage and detect low memory | |
324 MemoryService::track_memory_usage(); | |
325 heap->update_counters(); | |
326 | |
327 if (PrintGCDetails) { | |
328 if (size_policy->print_gc_time_limit_would_be_exceeded()) { | |
329 if (size_policy->gc_time_limit_exceeded()) { | |
330 gclog_or_tty->print_cr(" GC time is exceeding GCTimeLimit " | |
331 "of %d%%", GCTimeLimit); | |
332 } else { | |
333 gclog_or_tty->print_cr(" GC time would exceed GCTimeLimit " | |
334 "of %d%%", GCTimeLimit); | |
335 } | |
336 } | |
337 size_policy->set_print_gc_time_limit_would_be_exceeded(false); | |
338 } | |
339 } | |
340 | |
341 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { | |
342 HandleMark hm; // Discard invalid handles created during verification | |
343 gclog_or_tty->print(" VerifyAfterGC:"); | |
344 Universe::verify(false); | |
345 } | |
346 | |
347 // Re-verify object start arrays | |
348 if (VerifyObjectStartArray && | |
349 VerifyAfterGC) { | |
350 old_gen->verify_object_start_array(); | |
351 perm_gen->verify_object_start_array(); | |
352 } | |
353 | |
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354 if (ZapUnusedHeapArea) { |
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355 old_gen->object_space()->check_mangled_unused_area_complete(); |
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356 perm_gen->object_space()->check_mangled_unused_area_complete(); |
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357 } |
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358 |
0 | 359 NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); |
360 | |
361 if (PrintHeapAtGC) { | |
362 Universe::print_heap_after_gc(); | |
363 } | |
364 } | |
365 | |
366 bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy, | |
367 PSYoungGen* young_gen, | |
368 PSOldGen* old_gen) { | |
369 MutableSpace* const eden_space = young_gen->eden_space(); | |
370 assert(!eden_space->is_empty(), "eden must be non-empty"); | |
371 assert(young_gen->virtual_space()->alignment() == | |
372 old_gen->virtual_space()->alignment(), "alignments do not match"); | |
373 | |
374 if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) { | |
375 return false; | |
376 } | |
377 | |
378 // Both generations must be completely committed. | |
379 if (young_gen->virtual_space()->uncommitted_size() != 0) { | |
380 return false; | |
381 } | |
382 if (old_gen->virtual_space()->uncommitted_size() != 0) { | |
383 return false; | |
384 } | |
385 | |
386 // Figure out how much to take from eden. Include the average amount promoted | |
387 // in the total; otherwise the next young gen GC will simply bail out to a | |
388 // full GC. | |
389 const size_t alignment = old_gen->virtual_space()->alignment(); | |
390 const size_t eden_used = eden_space->used_in_bytes(); | |
391 const size_t promoted = (size_t)(size_policy->avg_promoted()->padded_average()); | |
392 const size_t absorb_size = align_size_up(eden_used + promoted, alignment); | |
393 const size_t eden_capacity = eden_space->capacity_in_bytes(); | |
394 | |
395 if (absorb_size >= eden_capacity) { | |
396 return false; // Must leave some space in eden. | |
397 } | |
398 | |
399 const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size; | |
400 if (new_young_size < young_gen->min_gen_size()) { | |
401 return false; // Respect young gen minimum size. | |
402 } | |
403 | |
404 if (TraceAdaptiveGCBoundary && Verbose) { | |
405 gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: " | |
406 "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K " | |
407 "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K " | |
408 "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ", | |
409 absorb_size / K, | |
410 eden_capacity / K, (eden_capacity - absorb_size) / K, | |
411 young_gen->from_space()->used_in_bytes() / K, | |
412 young_gen->to_space()->used_in_bytes() / K, | |
413 young_gen->capacity_in_bytes() / K, new_young_size / K); | |
414 } | |
415 | |
416 // Fill the unused part of the old gen. | |
417 MutableSpace* const old_space = old_gen->object_space(); | |
418 MemRegion old_gen_unused(old_space->top(), old_space->end()); | |
419 | |
420 // If the unused part of the old gen cannot be filled, skip | |
421 // absorbing eden. | |
422 if (old_gen_unused.word_size() < SharedHeap::min_fill_size()) { | |
423 return false; | |
424 } | |
425 | |
426 if (!old_gen_unused.is_empty()) { | |
427 SharedHeap::fill_region_with_object(old_gen_unused); | |
428 } | |
429 | |
430 // Take the live data from eden and set both top and end in the old gen to | |
431 // eden top. (Need to set end because reset_after_change() mangles the region | |
432 // from end to virtual_space->high() in debug builds). | |
433 HeapWord* const new_top = eden_space->top(); | |
434 old_gen->virtual_space()->expand_into(young_gen->virtual_space(), | |
435 absorb_size); | |
436 young_gen->reset_after_change(); | |
437 old_space->set_top(new_top); | |
438 old_space->set_end(new_top); | |
439 old_gen->reset_after_change(); | |
440 | |
441 // Update the object start array for the filler object and the data from eden. | |
442 ObjectStartArray* const start_array = old_gen->start_array(); | |
443 HeapWord* const start = old_gen_unused.start(); | |
444 for (HeapWord* addr = start; addr < new_top; addr += oop(addr)->size()) { | |
445 start_array->allocate_block(addr); | |
446 } | |
447 | |
448 // Could update the promoted average here, but it is not typically updated at | |
449 // full GCs and the value to use is unclear. Something like | |
450 // | |
451 // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc. | |
452 | |
453 size_policy->set_bytes_absorbed_from_eden(absorb_size); | |
454 return true; | |
455 } | |
456 | |
457 void PSMarkSweep::allocate_stacks() { | |
458 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
459 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
460 | |
461 PSYoungGen* young_gen = heap->young_gen(); | |
462 | |
463 MutableSpace* to_space = young_gen->to_space(); | |
464 _preserved_marks = (PreservedMark*)to_space->top(); | |
465 _preserved_count = 0; | |
466 | |
467 // We want to calculate the size in bytes first. | |
468 _preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte)); | |
469 // Now divide by the size of a PreservedMark | |
470 _preserved_count_max /= sizeof(PreservedMark); | |
471 | |
472 _preserved_mark_stack = NULL; | |
473 _preserved_oop_stack = NULL; | |
474 | |
475 _marking_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true); | |
476 | |
477 int size = SystemDictionary::number_of_classes() * 2; | |
478 _revisit_klass_stack = new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true); | |
479 } | |
480 | |
481 | |
482 void PSMarkSweep::deallocate_stacks() { | |
483 if (_preserved_oop_stack) { | |
484 delete _preserved_mark_stack; | |
485 _preserved_mark_stack = NULL; | |
486 delete _preserved_oop_stack; | |
487 _preserved_oop_stack = NULL; | |
488 } | |
489 | |
490 delete _marking_stack; | |
491 delete _revisit_klass_stack; | |
492 } | |
493 | |
494 void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) { | |
495 // Recursively traverse all live objects and mark them | |
496 EventMark m("1 mark object"); | |
497 TraceTime tm("phase 1", PrintGCDetails && Verbose, true, gclog_or_tty); | |
498 trace(" 1"); | |
499 | |
500 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
501 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
502 | |
503 // General strong roots. | |
504 Universe::oops_do(mark_and_push_closure()); | |
505 ReferenceProcessor::oops_do(mark_and_push_closure()); | |
506 JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles | |
507 Threads::oops_do(mark_and_push_closure()); | |
508 ObjectSynchronizer::oops_do(mark_and_push_closure()); | |
509 FlatProfiler::oops_do(mark_and_push_closure()); | |
510 Management::oops_do(mark_and_push_closure()); | |
511 JvmtiExport::oops_do(mark_and_push_closure()); | |
512 SystemDictionary::always_strong_oops_do(mark_and_push_closure()); | |
513 vmSymbols::oops_do(mark_and_push_closure()); | |
514 | |
515 // Flush marking stack. | |
516 follow_stack(); | |
517 | |
518 // Process reference objects found during marking | |
519 { | |
520 ReferencePolicy *soft_ref_policy; | |
521 if (clear_all_softrefs) { | |
522 soft_ref_policy = new AlwaysClearPolicy(); | |
523 } else { | |
524 #ifdef COMPILER2 | |
525 soft_ref_policy = new LRUMaxHeapPolicy(); | |
526 #else | |
527 soft_ref_policy = new LRUCurrentHeapPolicy(); | |
528 #endif // COMPILER2 | |
529 } | |
530 assert(soft_ref_policy != NULL,"No soft reference policy"); | |
531 ref_processor()->process_discovered_references( | |
532 soft_ref_policy, is_alive_closure(), mark_and_push_closure(), | |
533 follow_stack_closure(), NULL); | |
534 } | |
535 | |
536 // Follow system dictionary roots and unload classes | |
537 bool purged_class = SystemDictionary::do_unloading(is_alive_closure()); | |
538 | |
539 // Follow code cache roots | |
540 CodeCache::do_unloading(is_alive_closure(), mark_and_push_closure(), | |
541 purged_class); | |
542 follow_stack(); // Flush marking stack | |
543 | |
544 // Update subklass/sibling/implementor links of live klasses | |
545 follow_weak_klass_links(); | |
546 assert(_marking_stack->is_empty(), "just drained"); | |
547 | |
548 // Visit symbol and interned string tables and delete unmarked oops | |
549 SymbolTable::unlink(is_alive_closure()); | |
550 StringTable::unlink(is_alive_closure()); | |
551 | |
552 assert(_marking_stack->is_empty(), "stack should be empty by now"); | |
553 } | |
554 | |
555 | |
556 void PSMarkSweep::mark_sweep_phase2() { | |
557 EventMark m("2 compute new addresses"); | |
558 TraceTime tm("phase 2", PrintGCDetails && Verbose, true, gclog_or_tty); | |
559 trace("2"); | |
560 | |
561 // Now all live objects are marked, compute the new object addresses. | |
562 | |
563 // It is imperative that we traverse perm_gen LAST. If dead space is | |
564 // allowed a range of dead object may get overwritten by a dead int | |
565 // array. If perm_gen is not traversed last a klassOop may get | |
566 // overwritten. This is fine since it is dead, but if the class has dead | |
567 // instances we have to skip them, and in order to find their size we | |
568 // need the klassOop! | |
569 // | |
570 // It is not required that we traverse spaces in the same order in | |
571 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops | |
572 // tracking expects us to do so. See comment under phase4. | |
573 | |
574 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
575 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
576 | |
577 PSOldGen* old_gen = heap->old_gen(); | |
578 PSPermGen* perm_gen = heap->perm_gen(); | |
579 | |
580 // Begin compacting into the old gen | |
581 PSMarkSweepDecorator::set_destination_decorator_tenured(); | |
582 | |
583 // This will also compact the young gen spaces. | |
584 old_gen->precompact(); | |
585 | |
586 // Compact the perm gen into the perm gen | |
587 PSMarkSweepDecorator::set_destination_decorator_perm_gen(); | |
588 | |
589 perm_gen->precompact(); | |
590 } | |
591 | |
592 // This should be moved to the shared markSweep code! | |
593 class PSAlwaysTrueClosure: public BoolObjectClosure { | |
594 public: | |
595 void do_object(oop p) { ShouldNotReachHere(); } | |
596 bool do_object_b(oop p) { return true; } | |
597 }; | |
598 static PSAlwaysTrueClosure always_true; | |
599 | |
600 void PSMarkSweep::mark_sweep_phase3() { | |
601 // Adjust the pointers to reflect the new locations | |
602 EventMark m("3 adjust pointers"); | |
603 TraceTime tm("phase 3", PrintGCDetails && Verbose, true, gclog_or_tty); | |
604 trace("3"); | |
605 | |
606 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
607 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
608 | |
609 PSYoungGen* young_gen = heap->young_gen(); | |
610 PSOldGen* old_gen = heap->old_gen(); | |
611 PSPermGen* perm_gen = heap->perm_gen(); | |
612 | |
613 // General strong roots. | |
614 Universe::oops_do(adjust_root_pointer_closure()); | |
615 ReferenceProcessor::oops_do(adjust_root_pointer_closure()); | |
616 JNIHandles::oops_do(adjust_root_pointer_closure()); // Global (strong) JNI handles | |
617 Threads::oops_do(adjust_root_pointer_closure()); | |
618 ObjectSynchronizer::oops_do(adjust_root_pointer_closure()); | |
619 FlatProfiler::oops_do(adjust_root_pointer_closure()); | |
620 Management::oops_do(adjust_root_pointer_closure()); | |
621 JvmtiExport::oops_do(adjust_root_pointer_closure()); | |
622 // SO_AllClasses | |
623 SystemDictionary::oops_do(adjust_root_pointer_closure()); | |
624 vmSymbols::oops_do(adjust_root_pointer_closure()); | |
625 | |
626 // Now adjust pointers in remaining weak roots. (All of which should | |
627 // have been cleared if they pointed to non-surviving objects.) | |
628 // Global (weak) JNI handles | |
629 JNIHandles::weak_oops_do(&always_true, adjust_root_pointer_closure()); | |
630 | |
631 CodeCache::oops_do(adjust_pointer_closure()); | |
632 SymbolTable::oops_do(adjust_root_pointer_closure()); | |
633 StringTable::oops_do(adjust_root_pointer_closure()); | |
634 ref_processor()->weak_oops_do(adjust_root_pointer_closure()); | |
635 PSScavenge::reference_processor()->weak_oops_do(adjust_root_pointer_closure()); | |
636 | |
637 adjust_marks(); | |
638 | |
639 young_gen->adjust_pointers(); | |
640 old_gen->adjust_pointers(); | |
641 perm_gen->adjust_pointers(); | |
642 } | |
643 | |
644 void PSMarkSweep::mark_sweep_phase4() { | |
645 EventMark m("4 compact heap"); | |
646 TraceTime tm("phase 4", PrintGCDetails && Verbose, true, gclog_or_tty); | |
647 trace("4"); | |
648 | |
649 // All pointers are now adjusted, move objects accordingly | |
650 | |
651 // It is imperative that we traverse perm_gen first in phase4. All | |
652 // classes must be allocated earlier than their instances, and traversing | |
653 // perm_gen first makes sure that all klassOops have moved to their new | |
654 // location before any instance does a dispatch through it's klass! | |
655 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
656 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
657 | |
658 PSYoungGen* young_gen = heap->young_gen(); | |
659 PSOldGen* old_gen = heap->old_gen(); | |
660 PSPermGen* perm_gen = heap->perm_gen(); | |
661 | |
662 perm_gen->compact(); | |
663 old_gen->compact(); | |
664 young_gen->compact(); | |
665 } | |
666 | |
667 jlong PSMarkSweep::millis_since_last_gc() { | |
668 jlong ret_val = os::javaTimeMillis() - _time_of_last_gc; | |
669 // XXX See note in genCollectedHeap::millis_since_last_gc(). | |
670 if (ret_val < 0) { | |
671 NOT_PRODUCT(warning("time warp: %d", ret_val);) | |
672 return 0; | |
673 } | |
674 return ret_val; | |
675 } | |
676 | |
677 void PSMarkSweep::reset_millis_since_last_gc() { | |
678 _time_of_last_gc = os::javaTimeMillis(); | |
679 } |