Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp @ 993:54b3b351d6f9
Merge
author | jrose |
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date | Wed, 23 Sep 2009 23:56:15 -0700 |
parents | 148e5441d916 8b46c4d82093 |
children | 2a1472c30599 |
rev | line source |
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0 | 1 /* |
579 | 2 * Copyright 2001-2009 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 | |
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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 | |
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128 heap->pre_full_gc_dump(); |
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129 |
0 | 130 // Filled in below to track the state of the young gen after the collection. |
131 bool eden_empty; | |
132 bool survivors_empty; | |
133 bool young_gen_empty; | |
134 | |
135 { | |
136 HandleMark hm; | |
137 const bool is_system_gc = gc_cause == GCCause::_java_lang_system_gc; | |
138 // This is useful for debugging but don't change the output the | |
139 // the customer sees. | |
140 const char* gc_cause_str = "Full GC"; | |
141 if (is_system_gc && PrintGCDetails) { | |
142 gc_cause_str = "Full GC (System)"; | |
143 } | |
144 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); | |
145 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); | |
146 TraceTime t1(gc_cause_str, PrintGC, !PrintGCDetails, gclog_or_tty); | |
147 TraceCollectorStats tcs(counters()); | |
148 TraceMemoryManagerStats tms(true /* Full GC */); | |
149 | |
150 if (TraceGen1Time) accumulated_time()->start(); | |
151 | |
152 // Let the size policy know we're starting | |
153 size_policy->major_collection_begin(); | |
154 | |
155 // When collecting the permanent generation methodOops may be moving, | |
156 // so we either have to flush all bcp data or convert it into bci. | |
157 CodeCache::gc_prologue(); | |
158 Threads::gc_prologue(); | |
159 BiasedLocking::preserve_marks(); | |
160 | |
161 // Capture heap size before collection for printing. | |
162 size_t prev_used = heap->used(); | |
163 | |
164 // Capture perm gen size before collection for sizing. | |
165 size_t perm_gen_prev_used = perm_gen->used_in_bytes(); | |
166 | |
167 // For PrintGCDetails | |
168 size_t old_gen_prev_used = old_gen->used_in_bytes(); | |
169 size_t young_gen_prev_used = young_gen->used_in_bytes(); | |
170 | |
171 allocate_stacks(); | |
172 | |
173 NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); | |
174 COMPILER2_PRESENT(DerivedPointerTable::clear()); | |
175 | |
176 ref_processor()->enable_discovery(); | |
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177 ref_processor()->setup_policy(clear_all_softrefs); |
0 | 178 |
179 mark_sweep_phase1(clear_all_softrefs); | |
180 | |
181 mark_sweep_phase2(); | |
182 | |
183 // Don't add any more derived pointers during phase3 | |
184 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity")); | |
185 COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); | |
186 | |
187 mark_sweep_phase3(); | |
188 | |
189 mark_sweep_phase4(); | |
190 | |
191 restore_marks(); | |
192 | |
193 deallocate_stacks(); | |
194 | |
263
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195 if (ZapUnusedHeapArea) { |
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196 // Do a complete mangle (top to end) because the usage for |
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197 // scratch does not maintain a top pointer. |
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198 young_gen->to_space()->mangle_unused_area_complete(); |
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199 } |
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200 |
0 | 201 eden_empty = young_gen->eden_space()->is_empty(); |
202 if (!eden_empty) { | |
203 eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen); | |
204 } | |
205 | |
206 // Update heap occupancy information which is used as | |
207 // input to soft ref clearing policy at the next gc. | |
208 Universe::update_heap_info_at_gc(); | |
209 | |
210 survivors_empty = young_gen->from_space()->is_empty() && | |
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211 young_gen->to_space()->is_empty(); |
0 | 212 young_gen_empty = eden_empty && survivors_empty; |
213 | |
214 BarrierSet* bs = heap->barrier_set(); | |
215 if (bs->is_a(BarrierSet::ModRef)) { | |
216 ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs; | |
217 MemRegion old_mr = heap->old_gen()->reserved(); | |
218 MemRegion perm_mr = heap->perm_gen()->reserved(); | |
219 assert(perm_mr.end() <= old_mr.start(), "Generations out of order"); | |
220 | |
221 if (young_gen_empty) { | |
222 modBS->clear(MemRegion(perm_mr.start(), old_mr.end())); | |
223 } else { | |
224 modBS->invalidate(MemRegion(perm_mr.start(), old_mr.end())); | |
225 } | |
226 } | |
227 | |
228 BiasedLocking::restore_marks(); | |
229 Threads::gc_epilogue(); | |
230 CodeCache::gc_epilogue(); | |
231 | |
232 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); | |
233 | |
234 ref_processor()->enqueue_discovered_references(NULL); | |
235 | |
236 // Update time of last GC | |
237 reset_millis_since_last_gc(); | |
238 | |
239 // Let the size policy know we're done | |
240 size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause); | |
241 | |
242 if (UseAdaptiveSizePolicy) { | |
243 | |
244 if (PrintAdaptiveSizePolicy) { | |
245 gclog_or_tty->print("AdaptiveSizeStart: "); | |
246 gclog_or_tty->stamp(); | |
247 gclog_or_tty->print_cr(" collection: %d ", | |
248 heap->total_collections()); | |
249 if (Verbose) { | |
250 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d" | |
251 " perm_gen_capacity: %d ", | |
252 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(), | |
253 perm_gen->capacity_in_bytes()); | |
254 } | |
255 } | |
256 | |
257 // Don't check if the size_policy is ready here. Let | |
258 // the size_policy check that internally. | |
259 if (UseAdaptiveGenerationSizePolicyAtMajorCollection && | |
260 ((gc_cause != GCCause::_java_lang_system_gc) || | |
261 UseAdaptiveSizePolicyWithSystemGC)) { | |
262 // Calculate optimal free space amounts | |
263 assert(young_gen->max_size() > | |
264 young_gen->from_space()->capacity_in_bytes() + | |
265 young_gen->to_space()->capacity_in_bytes(), | |
266 "Sizes of space in young gen are out-of-bounds"); | |
267 size_t max_eden_size = young_gen->max_size() - | |
268 young_gen->from_space()->capacity_in_bytes() - | |
269 young_gen->to_space()->capacity_in_bytes(); | |
270 size_policy->compute_generation_free_space(young_gen->used_in_bytes(), | |
271 young_gen->eden_space()->used_in_bytes(), | |
272 old_gen->used_in_bytes(), | |
273 perm_gen->used_in_bytes(), | |
274 young_gen->eden_space()->capacity_in_bytes(), | |
275 old_gen->max_gen_size(), | |
276 max_eden_size, | |
277 true /* full gc*/, | |
278 gc_cause); | |
279 | |
280 heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes()); | |
281 | |
282 // Don't resize the young generation at an major collection. A | |
283 // desired young generation size may have been calculated but | |
284 // resizing the young generation complicates the code because the | |
285 // resizing of the old generation may have moved the boundary | |
286 // between the young generation and the old generation. Let the | |
287 // young generation resizing happen at the minor collections. | |
288 } | |
289 if (PrintAdaptiveSizePolicy) { | |
290 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ", | |
291 heap->total_collections()); | |
292 } | |
293 } | |
294 | |
295 if (UsePerfData) { | |
296 heap->gc_policy_counters()->update_counters(); | |
297 heap->gc_policy_counters()->update_old_capacity( | |
298 old_gen->capacity_in_bytes()); | |
299 heap->gc_policy_counters()->update_young_capacity( | |
300 young_gen->capacity_in_bytes()); | |
301 } | |
302 | |
303 heap->resize_all_tlabs(); | |
304 | |
305 // We collected the perm gen, so we'll resize it here. | |
306 perm_gen->compute_new_size(perm_gen_prev_used); | |
307 | |
308 if (TraceGen1Time) accumulated_time()->stop(); | |
309 | |
310 if (PrintGC) { | |
311 if (PrintGCDetails) { | |
312 // Don't print a GC timestamp here. This is after the GC so | |
313 // would be confusing. | |
314 young_gen->print_used_change(young_gen_prev_used); | |
315 old_gen->print_used_change(old_gen_prev_used); | |
316 } | |
317 heap->print_heap_change(prev_used); | |
318 // Do perm gen after heap becase prev_used does | |
319 // not include the perm gen (done this way in the other | |
320 // collectors). | |
321 if (PrintGCDetails) { | |
322 perm_gen->print_used_change(perm_gen_prev_used); | |
323 } | |
324 } | |
325 | |
326 // Track memory usage and detect low memory | |
327 MemoryService::track_memory_usage(); | |
328 heap->update_counters(); | |
329 | |
330 if (PrintGCDetails) { | |
331 if (size_policy->print_gc_time_limit_would_be_exceeded()) { | |
332 if (size_policy->gc_time_limit_exceeded()) { | |
333 gclog_or_tty->print_cr(" GC time is exceeding GCTimeLimit " | |
334 "of %d%%", GCTimeLimit); | |
335 } else { | |
336 gclog_or_tty->print_cr(" GC time would exceed GCTimeLimit " | |
337 "of %d%%", GCTimeLimit); | |
338 } | |
339 } | |
340 size_policy->set_print_gc_time_limit_would_be_exceeded(false); | |
341 } | |
342 } | |
343 | |
344 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { | |
345 HandleMark hm; // Discard invalid handles created during verification | |
346 gclog_or_tty->print(" VerifyAfterGC:"); | |
347 Universe::verify(false); | |
348 } | |
349 | |
350 // Re-verify object start arrays | |
351 if (VerifyObjectStartArray && | |
352 VerifyAfterGC) { | |
353 old_gen->verify_object_start_array(); | |
354 perm_gen->verify_object_start_array(); | |
355 } | |
356 | |
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357 if (ZapUnusedHeapArea) { |
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358 old_gen->object_space()->check_mangled_unused_area_complete(); |
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359 perm_gen->object_space()->check_mangled_unused_area_complete(); |
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360 } |
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361 |
0 | 362 NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); |
363 | |
364 if (PrintHeapAtGC) { | |
365 Universe::print_heap_after_gc(); | |
366 } | |
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367 |
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368 heap->post_full_gc_dump(); |
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369 |
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370 #ifdef TRACESPINNING |
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371 ParallelTaskTerminator::print_termination_counts(); |
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372 #endif |
0 | 373 } |
374 | |
375 bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy, | |
376 PSYoungGen* young_gen, | |
377 PSOldGen* old_gen) { | |
378 MutableSpace* const eden_space = young_gen->eden_space(); | |
379 assert(!eden_space->is_empty(), "eden must be non-empty"); | |
380 assert(young_gen->virtual_space()->alignment() == | |
381 old_gen->virtual_space()->alignment(), "alignments do not match"); | |
382 | |
383 if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) { | |
384 return false; | |
385 } | |
386 | |
387 // Both generations must be completely committed. | |
388 if (young_gen->virtual_space()->uncommitted_size() != 0) { | |
389 return false; | |
390 } | |
391 if (old_gen->virtual_space()->uncommitted_size() != 0) { | |
392 return false; | |
393 } | |
394 | |
395 // Figure out how much to take from eden. Include the average amount promoted | |
396 // in the total; otherwise the next young gen GC will simply bail out to a | |
397 // full GC. | |
398 const size_t alignment = old_gen->virtual_space()->alignment(); | |
399 const size_t eden_used = eden_space->used_in_bytes(); | |
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400 const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average(); |
0 | 401 const size_t absorb_size = align_size_up(eden_used + promoted, alignment); |
402 const size_t eden_capacity = eden_space->capacity_in_bytes(); | |
403 | |
404 if (absorb_size >= eden_capacity) { | |
405 return false; // Must leave some space in eden. | |
406 } | |
407 | |
408 const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size; | |
409 if (new_young_size < young_gen->min_gen_size()) { | |
410 return false; // Respect young gen minimum size. | |
411 } | |
412 | |
413 if (TraceAdaptiveGCBoundary && Verbose) { | |
414 gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: " | |
415 "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K " | |
416 "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K " | |
417 "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ", | |
418 absorb_size / K, | |
419 eden_capacity / K, (eden_capacity - absorb_size) / K, | |
420 young_gen->from_space()->used_in_bytes() / K, | |
421 young_gen->to_space()->used_in_bytes() / K, | |
422 young_gen->capacity_in_bytes() / K, new_young_size / K); | |
423 } | |
424 | |
425 // Fill the unused part of the old gen. | |
426 MutableSpace* const old_space = old_gen->object_space(); | |
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427 HeapWord* const unused_start = old_space->top(); |
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428 size_t const unused_words = pointer_delta(old_space->end(), unused_start); |
0 | 429 |
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430 if (unused_words > 0) { |
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431 if (unused_words < CollectedHeap::min_fill_size()) { |
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432 return false; // If the old gen cannot be filled, must give up. |
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433 } |
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434 CollectedHeap::fill_with_objects(unused_start, unused_words); |
0 | 435 } |
436 | |
437 // Take the live data from eden and set both top and end in the old gen to | |
438 // eden top. (Need to set end because reset_after_change() mangles the region | |
439 // from end to virtual_space->high() in debug builds). | |
440 HeapWord* const new_top = eden_space->top(); | |
441 old_gen->virtual_space()->expand_into(young_gen->virtual_space(), | |
442 absorb_size); | |
443 young_gen->reset_after_change(); | |
444 old_space->set_top(new_top); | |
445 old_space->set_end(new_top); | |
446 old_gen->reset_after_change(); | |
447 | |
448 // Update the object start array for the filler object and the data from eden. | |
449 ObjectStartArray* const start_array = old_gen->start_array(); | |
481
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450 for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) { |
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451 start_array->allocate_block(p); |
0 | 452 } |
453 | |
454 // Could update the promoted average here, but it is not typically updated at | |
455 // full GCs and the value to use is unclear. Something like | |
456 // | |
457 // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc. | |
458 | |
459 size_policy->set_bytes_absorbed_from_eden(absorb_size); | |
460 return true; | |
461 } | |
462 | |
463 void PSMarkSweep::allocate_stacks() { | |
464 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
465 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
466 | |
467 PSYoungGen* young_gen = heap->young_gen(); | |
468 | |
469 MutableSpace* to_space = young_gen->to_space(); | |
470 _preserved_marks = (PreservedMark*)to_space->top(); | |
471 _preserved_count = 0; | |
472 | |
473 // We want to calculate the size in bytes first. | |
474 _preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte)); | |
475 // Now divide by the size of a PreservedMark | |
476 _preserved_count_max /= sizeof(PreservedMark); | |
477 | |
478 _preserved_mark_stack = NULL; | |
479 _preserved_oop_stack = NULL; | |
480 | |
481 _marking_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true); | |
482 | |
483 int size = SystemDictionary::number_of_classes() * 2; | |
484 _revisit_klass_stack = new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true); | |
941 | 485 // (#klass/k)^2, for k ~ 10 appears a better setting, but this will have to do for |
486 // now until we investigate a more optimal setting. | |
487 _revisit_mdo_stack = new (ResourceObj::C_HEAP) GrowableArray<DataLayout*>(size*2, true); | |
0 | 488 } |
489 | |
490 | |
491 void PSMarkSweep::deallocate_stacks() { | |
492 if (_preserved_oop_stack) { | |
493 delete _preserved_mark_stack; | |
494 _preserved_mark_stack = NULL; | |
495 delete _preserved_oop_stack; | |
496 _preserved_oop_stack = NULL; | |
497 } | |
498 | |
499 delete _marking_stack; | |
500 delete _revisit_klass_stack; | |
941 | 501 delete _revisit_mdo_stack; |
0 | 502 } |
503 | |
504 void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) { | |
505 // Recursively traverse all live objects and mark them | |
506 EventMark m("1 mark object"); | |
507 TraceTime tm("phase 1", PrintGCDetails && Verbose, true, gclog_or_tty); | |
508 trace(" 1"); | |
509 | |
510 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
511 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
512 | |
513 // General strong roots. | |
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514 { |
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515 ParallelScavengeHeap::ParStrongRootsScope psrs; |
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516 Universe::oops_do(mark_and_push_closure()); |
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517 ReferenceProcessor::oops_do(mark_and_push_closure()); |
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518 JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles |
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519 CodeBlobToOopClosure each_active_code_blob(mark_and_push_closure(), /*do_marking=*/ true); |
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520 Threads::oops_do(mark_and_push_closure(), &each_active_code_blob); |
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521 ObjectSynchronizer::oops_do(mark_and_push_closure()); |
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522 FlatProfiler::oops_do(mark_and_push_closure()); |
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523 Management::oops_do(mark_and_push_closure()); |
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524 JvmtiExport::oops_do(mark_and_push_closure()); |
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525 SystemDictionary::always_strong_oops_do(mark_and_push_closure()); |
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526 vmSymbols::oops_do(mark_and_push_closure()); |
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527 // Do not treat nmethods as strong roots for mark/sweep, since we can unload them. |
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528 //CodeCache::scavenge_root_nmethods_do(CodeBlobToOopClosure(mark_and_push_closure())); |
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529 } |
0 | 530 |
531 // Flush marking stack. | |
532 follow_stack(); | |
533 | |
534 // Process reference objects found during marking | |
535 { | |
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536 ref_processor()->setup_policy(clear_all_softrefs); |
0 | 537 ref_processor()->process_discovered_references( |
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538 is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL); |
0 | 539 } |
540 | |
541 // Follow system dictionary roots and unload classes | |
542 bool purged_class = SystemDictionary::do_unloading(is_alive_closure()); | |
543 | |
544 // Follow code cache roots | |
545 CodeCache::do_unloading(is_alive_closure(), mark_and_push_closure(), | |
546 purged_class); | |
547 follow_stack(); // Flush marking stack | |
548 | |
549 // Update subklass/sibling/implementor links of live klasses | |
550 follow_weak_klass_links(); | |
551 assert(_marking_stack->is_empty(), "just drained"); | |
552 | |
941 | 553 // Visit memoized mdo's and clear unmarked weak refs |
554 follow_mdo_weak_refs(); | |
555 assert(_marking_stack->is_empty(), "just drained"); | |
556 | |
0 | 557 // Visit symbol and interned string tables and delete unmarked oops |
558 SymbolTable::unlink(is_alive_closure()); | |
559 StringTable::unlink(is_alive_closure()); | |
560 | |
561 assert(_marking_stack->is_empty(), "stack should be empty by now"); | |
562 } | |
563 | |
564 | |
565 void PSMarkSweep::mark_sweep_phase2() { | |
566 EventMark m("2 compute new addresses"); | |
567 TraceTime tm("phase 2", PrintGCDetails && Verbose, true, gclog_or_tty); | |
568 trace("2"); | |
569 | |
570 // Now all live objects are marked, compute the new object addresses. | |
571 | |
572 // It is imperative that we traverse perm_gen LAST. If dead space is | |
573 // allowed a range of dead object may get overwritten by a dead int | |
574 // array. If perm_gen is not traversed last a klassOop may get | |
575 // overwritten. This is fine since it is dead, but if the class has dead | |
576 // instances we have to skip them, and in order to find their size we | |
577 // need the klassOop! | |
578 // | |
579 // It is not required that we traverse spaces in the same order in | |
580 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops | |
581 // tracking expects us to do so. See comment under phase4. | |
582 | |
583 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
584 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
585 | |
586 PSOldGen* old_gen = heap->old_gen(); | |
587 PSPermGen* perm_gen = heap->perm_gen(); | |
588 | |
589 // Begin compacting into the old gen | |
590 PSMarkSweepDecorator::set_destination_decorator_tenured(); | |
591 | |
592 // This will also compact the young gen spaces. | |
593 old_gen->precompact(); | |
594 | |
595 // Compact the perm gen into the perm gen | |
596 PSMarkSweepDecorator::set_destination_decorator_perm_gen(); | |
597 | |
598 perm_gen->precompact(); | |
599 } | |
600 | |
601 // This should be moved to the shared markSweep code! | |
602 class PSAlwaysTrueClosure: public BoolObjectClosure { | |
603 public: | |
604 void do_object(oop p) { ShouldNotReachHere(); } | |
605 bool do_object_b(oop p) { return true; } | |
606 }; | |
607 static PSAlwaysTrueClosure always_true; | |
608 | |
609 void PSMarkSweep::mark_sweep_phase3() { | |
610 // Adjust the pointers to reflect the new locations | |
611 EventMark m("3 adjust pointers"); | |
612 TraceTime tm("phase 3", PrintGCDetails && Verbose, true, gclog_or_tty); | |
613 trace("3"); | |
614 | |
615 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
616 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
617 | |
618 PSYoungGen* young_gen = heap->young_gen(); | |
619 PSOldGen* old_gen = heap->old_gen(); | |
620 PSPermGen* perm_gen = heap->perm_gen(); | |
621 | |
622 // General strong roots. | |
623 Universe::oops_do(adjust_root_pointer_closure()); | |
624 ReferenceProcessor::oops_do(adjust_root_pointer_closure()); | |
625 JNIHandles::oops_do(adjust_root_pointer_closure()); // Global (strong) JNI handles | |
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626 Threads::oops_do(adjust_root_pointer_closure(), NULL); |
0 | 627 ObjectSynchronizer::oops_do(adjust_root_pointer_closure()); |
628 FlatProfiler::oops_do(adjust_root_pointer_closure()); | |
629 Management::oops_do(adjust_root_pointer_closure()); | |
630 JvmtiExport::oops_do(adjust_root_pointer_closure()); | |
631 // SO_AllClasses | |
632 SystemDictionary::oops_do(adjust_root_pointer_closure()); | |
633 vmSymbols::oops_do(adjust_root_pointer_closure()); | |
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634 //CodeCache::scavenge_root_nmethods_oops_do(adjust_root_pointer_closure()); |
0 | 635 |
636 // Now adjust pointers in remaining weak roots. (All of which should | |
637 // have been cleared if they pointed to non-surviving objects.) | |
638 // Global (weak) JNI handles | |
639 JNIHandles::weak_oops_do(&always_true, adjust_root_pointer_closure()); | |
640 | |
641 CodeCache::oops_do(adjust_pointer_closure()); | |
642 SymbolTable::oops_do(adjust_root_pointer_closure()); | |
643 StringTable::oops_do(adjust_root_pointer_closure()); | |
644 ref_processor()->weak_oops_do(adjust_root_pointer_closure()); | |
645 PSScavenge::reference_processor()->weak_oops_do(adjust_root_pointer_closure()); | |
646 | |
647 adjust_marks(); | |
648 | |
649 young_gen->adjust_pointers(); | |
650 old_gen->adjust_pointers(); | |
651 perm_gen->adjust_pointers(); | |
652 } | |
653 | |
654 void PSMarkSweep::mark_sweep_phase4() { | |
655 EventMark m("4 compact heap"); | |
656 TraceTime tm("phase 4", PrintGCDetails && Verbose, true, gclog_or_tty); | |
657 trace("4"); | |
658 | |
659 // All pointers are now adjusted, move objects accordingly | |
660 | |
661 // It is imperative that we traverse perm_gen first in phase4. All | |
662 // classes must be allocated earlier than their instances, and traversing | |
663 // perm_gen first makes sure that all klassOops have moved to their new | |
664 // location before any instance does a dispatch through it's klass! | |
665 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
666 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
667 | |
668 PSYoungGen* young_gen = heap->young_gen(); | |
669 PSOldGen* old_gen = heap->old_gen(); | |
670 PSPermGen* perm_gen = heap->perm_gen(); | |
671 | |
672 perm_gen->compact(); | |
673 old_gen->compact(); | |
674 young_gen->compact(); | |
675 } | |
676 | |
677 jlong PSMarkSweep::millis_since_last_gc() { | |
678 jlong ret_val = os::javaTimeMillis() - _time_of_last_gc; | |
679 // XXX See note in genCollectedHeap::millis_since_last_gc(). | |
680 if (ret_val < 0) { | |
681 NOT_PRODUCT(warning("time warp: %d", ret_val);) | |
682 return 0; | |
683 } | |
684 return ret_val; | |
685 } | |
686 | |
687 void PSMarkSweep::reset_millis_since_last_gc() { | |
688 _time_of_last_gc = os::javaTimeMillis(); | |
689 } |