Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/parallelScavenge/psMarkSweep.cpp @ 1544:1a88d3c58e1d
Merge
author | jrose |
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date | Thu, 20 May 2010 01:34:22 -0700 |
parents | 0bfd3fb24150 |
children | c18cbe5936b8 |
rev | line source |
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0 | 1 /* |
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2 * Copyright 2001-2010 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! | |
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49 // |
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50 // Note that the all_soft_refs_clear flag in the collector policy |
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51 // may be true because this method can be called without intervening |
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52 // activity. For example when the heap space is tight and full measure |
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53 // are being taken to free space. |
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54 |
0 | 55 void PSMarkSweep::invoke(bool maximum_heap_compaction) { |
56 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); | |
57 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); | |
58 assert(!Universe::heap()->is_gc_active(), "not reentrant"); | |
59 | |
60 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
61 GCCause::Cause gc_cause = heap->gc_cause(); | |
62 PSAdaptiveSizePolicy* policy = heap->size_policy(); | |
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63 IsGCActiveMark mark; |
0 | 64 |
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65 if (ScavengeBeforeFullGC) { |
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66 PSScavenge::invoke_no_policy(); |
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67 } |
0 | 68 |
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69 const bool clear_all_soft_refs = |
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70 heap->collector_policy()->should_clear_all_soft_refs(); |
0 | 71 |
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72 int count = (maximum_heap_compaction)?1:MarkSweepAlwaysCompactCount; |
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73 IntFlagSetting flag_setting(MarkSweepAlwaysCompactCount, count); |
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74 PSMarkSweep::invoke_no_policy(clear_all_soft_refs || maximum_heap_compaction); |
0 | 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 | |
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92 // The scope of casr should end after code that can change |
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93 // CollectorPolicy::_should_clear_all_soft_refs. |
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94 ClearedAllSoftRefs casr(clear_all_softrefs, heap->collector_policy()); |
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95 |
0 | 96 PSYoungGen* young_gen = heap->young_gen(); |
97 PSOldGen* old_gen = heap->old_gen(); | |
98 PSPermGen* perm_gen = heap->perm_gen(); | |
99 | |
100 // Increment the invocation count | |
101 heap->increment_total_collections(true /* full */); | |
102 | |
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103 // Save information needed to minimize mangling |
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104 heap->record_gen_tops_before_GC(); |
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105 |
0 | 106 // We need to track unique mark sweep invocations as well. |
107 _total_invocations++; | |
108 | |
109 AdaptiveSizePolicyOutput(size_policy, heap->total_collections()); | |
110 | |
111 if (PrintHeapAtGC) { | |
112 Universe::print_heap_before_gc(); | |
113 } | |
114 | |
115 // Fill in TLABs | |
116 heap->accumulate_statistics_all_tlabs(); | |
117 heap->ensure_parsability(true); // retire TLABs | |
118 | |
119 if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) { | |
120 HandleMark hm; // Discard invalid handles created during verification | |
121 gclog_or_tty->print(" VerifyBeforeGC:"); | |
122 Universe::verify(true); | |
123 } | |
124 | |
125 // Verify object start arrays | |
126 if (VerifyObjectStartArray && | |
127 VerifyBeforeGC) { | |
128 old_gen->verify_object_start_array(); | |
129 perm_gen->verify_object_start_array(); | |
130 } | |
131 | |
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132 heap->pre_full_gc_dump(); |
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133 |
0 | 134 // Filled in below to track the state of the young gen after the collection. |
135 bool eden_empty; | |
136 bool survivors_empty; | |
137 bool young_gen_empty; | |
138 | |
139 { | |
140 HandleMark hm; | |
141 const bool is_system_gc = gc_cause == GCCause::_java_lang_system_gc; | |
142 // This is useful for debugging but don't change the output the | |
143 // the customer sees. | |
144 const char* gc_cause_str = "Full GC"; | |
145 if (is_system_gc && PrintGCDetails) { | |
146 gc_cause_str = "Full GC (System)"; | |
147 } | |
148 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); | |
149 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); | |
150 TraceTime t1(gc_cause_str, PrintGC, !PrintGCDetails, gclog_or_tty); | |
151 TraceCollectorStats tcs(counters()); | |
152 TraceMemoryManagerStats tms(true /* Full GC */); | |
153 | |
154 if (TraceGen1Time) accumulated_time()->start(); | |
155 | |
156 // Let the size policy know we're starting | |
157 size_policy->major_collection_begin(); | |
158 | |
159 // When collecting the permanent generation methodOops may be moving, | |
160 // so we either have to flush all bcp data or convert it into bci. | |
161 CodeCache::gc_prologue(); | |
162 Threads::gc_prologue(); | |
163 BiasedLocking::preserve_marks(); | |
164 | |
165 // Capture heap size before collection for printing. | |
166 size_t prev_used = heap->used(); | |
167 | |
168 // Capture perm gen size before collection for sizing. | |
169 size_t perm_gen_prev_used = perm_gen->used_in_bytes(); | |
170 | |
171 // For PrintGCDetails | |
172 size_t old_gen_prev_used = old_gen->used_in_bytes(); | |
173 size_t young_gen_prev_used = young_gen->used_in_bytes(); | |
174 | |
175 allocate_stacks(); | |
176 | |
177 NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); | |
178 COMPILER2_PRESENT(DerivedPointerTable::clear()); | |
179 | |
180 ref_processor()->enable_discovery(); | |
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181 ref_processor()->setup_policy(clear_all_softrefs); |
0 | 182 |
183 mark_sweep_phase1(clear_all_softrefs); | |
184 | |
185 mark_sweep_phase2(); | |
186 | |
187 // Don't add any more derived pointers during phase3 | |
188 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity")); | |
189 COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); | |
190 | |
191 mark_sweep_phase3(); | |
192 | |
193 mark_sweep_phase4(); | |
194 | |
195 restore_marks(); | |
196 | |
197 deallocate_stacks(); | |
198 | |
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199 if (ZapUnusedHeapArea) { |
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200 // Do a complete mangle (top to end) because the usage for |
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201 // scratch does not maintain a top pointer. |
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202 young_gen->to_space()->mangle_unused_area_complete(); |
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203 } |
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204 |
0 | 205 eden_empty = young_gen->eden_space()->is_empty(); |
206 if (!eden_empty) { | |
207 eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen); | |
208 } | |
209 | |
210 // Update heap occupancy information which is used as | |
211 // input to soft ref clearing policy at the next gc. | |
212 Universe::update_heap_info_at_gc(); | |
213 | |
214 survivors_empty = young_gen->from_space()->is_empty() && | |
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215 young_gen->to_space()->is_empty(); |
0 | 216 young_gen_empty = eden_empty && survivors_empty; |
217 | |
218 BarrierSet* bs = heap->barrier_set(); | |
219 if (bs->is_a(BarrierSet::ModRef)) { | |
220 ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs; | |
221 MemRegion old_mr = heap->old_gen()->reserved(); | |
222 MemRegion perm_mr = heap->perm_gen()->reserved(); | |
223 assert(perm_mr.end() <= old_mr.start(), "Generations out of order"); | |
224 | |
225 if (young_gen_empty) { | |
226 modBS->clear(MemRegion(perm_mr.start(), old_mr.end())); | |
227 } else { | |
228 modBS->invalidate(MemRegion(perm_mr.start(), old_mr.end())); | |
229 } | |
230 } | |
231 | |
232 BiasedLocking::restore_marks(); | |
233 Threads::gc_epilogue(); | |
234 CodeCache::gc_epilogue(); | |
235 | |
236 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); | |
237 | |
238 ref_processor()->enqueue_discovered_references(NULL); | |
239 | |
240 // Update time of last GC | |
241 reset_millis_since_last_gc(); | |
242 | |
243 // Let the size policy know we're done | |
244 size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause); | |
245 | |
246 if (UseAdaptiveSizePolicy) { | |
247 | |
248 if (PrintAdaptiveSizePolicy) { | |
249 gclog_or_tty->print("AdaptiveSizeStart: "); | |
250 gclog_or_tty->stamp(); | |
251 gclog_or_tty->print_cr(" collection: %d ", | |
252 heap->total_collections()); | |
253 if (Verbose) { | |
254 gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d" | |
255 " perm_gen_capacity: %d ", | |
256 old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(), | |
257 perm_gen->capacity_in_bytes()); | |
258 } | |
259 } | |
260 | |
261 // Don't check if the size_policy is ready here. Let | |
262 // the size_policy check that internally. | |
263 if (UseAdaptiveGenerationSizePolicyAtMajorCollection && | |
264 ((gc_cause != GCCause::_java_lang_system_gc) || | |
265 UseAdaptiveSizePolicyWithSystemGC)) { | |
266 // Calculate optimal free space amounts | |
267 assert(young_gen->max_size() > | |
268 young_gen->from_space()->capacity_in_bytes() + | |
269 young_gen->to_space()->capacity_in_bytes(), | |
270 "Sizes of space in young gen are out-of-bounds"); | |
271 size_t max_eden_size = young_gen->max_size() - | |
272 young_gen->from_space()->capacity_in_bytes() - | |
273 young_gen->to_space()->capacity_in_bytes(); | |
274 size_policy->compute_generation_free_space(young_gen->used_in_bytes(), | |
275 young_gen->eden_space()->used_in_bytes(), | |
276 old_gen->used_in_bytes(), | |
277 perm_gen->used_in_bytes(), | |
278 young_gen->eden_space()->capacity_in_bytes(), | |
279 old_gen->max_gen_size(), | |
280 max_eden_size, | |
281 true /* full gc*/, | |
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282 gc_cause, |
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283 heap->collector_policy()); |
0 | 284 |
285 heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes()); | |
286 | |
287 // Don't resize the young generation at an major collection. A | |
288 // desired young generation size may have been calculated but | |
289 // resizing the young generation complicates the code because the | |
290 // resizing of the old generation may have moved the boundary | |
291 // between the young generation and the old generation. Let the | |
292 // young generation resizing happen at the minor collections. | |
293 } | |
294 if (PrintAdaptiveSizePolicy) { | |
295 gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ", | |
296 heap->total_collections()); | |
297 } | |
298 } | |
299 | |
300 if (UsePerfData) { | |
301 heap->gc_policy_counters()->update_counters(); | |
302 heap->gc_policy_counters()->update_old_capacity( | |
303 old_gen->capacity_in_bytes()); | |
304 heap->gc_policy_counters()->update_young_capacity( | |
305 young_gen->capacity_in_bytes()); | |
306 } | |
307 | |
308 heap->resize_all_tlabs(); | |
309 | |
310 // We collected the perm gen, so we'll resize it here. | |
311 perm_gen->compute_new_size(perm_gen_prev_used); | |
312 | |
313 if (TraceGen1Time) accumulated_time()->stop(); | |
314 | |
315 if (PrintGC) { | |
316 if (PrintGCDetails) { | |
317 // Don't print a GC timestamp here. This is after the GC so | |
318 // would be confusing. | |
319 young_gen->print_used_change(young_gen_prev_used); | |
320 old_gen->print_used_change(old_gen_prev_used); | |
321 } | |
322 heap->print_heap_change(prev_used); | |
323 // Do perm gen after heap becase prev_used does | |
324 // not include the perm gen (done this way in the other | |
325 // collectors). | |
326 if (PrintGCDetails) { | |
327 perm_gen->print_used_change(perm_gen_prev_used); | |
328 } | |
329 } | |
330 | |
331 // Track memory usage and detect low memory | |
332 MemoryService::track_memory_usage(); | |
333 heap->update_counters(); | |
334 } | |
335 | |
336 if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { | |
337 HandleMark hm; // Discard invalid handles created during verification | |
338 gclog_or_tty->print(" VerifyAfterGC:"); | |
339 Universe::verify(false); | |
340 } | |
341 | |
342 // Re-verify object start arrays | |
343 if (VerifyObjectStartArray && | |
344 VerifyAfterGC) { | |
345 old_gen->verify_object_start_array(); | |
346 perm_gen->verify_object_start_array(); | |
347 } | |
348 | |
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349 if (ZapUnusedHeapArea) { |
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350 old_gen->object_space()->check_mangled_unused_area_complete(); |
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351 perm_gen->object_space()->check_mangled_unused_area_complete(); |
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352 } |
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353 |
0 | 354 NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); |
355 | |
356 if (PrintHeapAtGC) { | |
357 Universe::print_heap_after_gc(); | |
358 } | |
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359 |
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360 heap->post_full_gc_dump(); |
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361 |
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362 #ifdef TRACESPINNING |
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363 ParallelTaskTerminator::print_termination_counts(); |
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364 #endif |
0 | 365 } |
366 | |
367 bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy, | |
368 PSYoungGen* young_gen, | |
369 PSOldGen* old_gen) { | |
370 MutableSpace* const eden_space = young_gen->eden_space(); | |
371 assert(!eden_space->is_empty(), "eden must be non-empty"); | |
372 assert(young_gen->virtual_space()->alignment() == | |
373 old_gen->virtual_space()->alignment(), "alignments do not match"); | |
374 | |
375 if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) { | |
376 return false; | |
377 } | |
378 | |
379 // Both generations must be completely committed. | |
380 if (young_gen->virtual_space()->uncommitted_size() != 0) { | |
381 return false; | |
382 } | |
383 if (old_gen->virtual_space()->uncommitted_size() != 0) { | |
384 return false; | |
385 } | |
386 | |
387 // Figure out how much to take from eden. Include the average amount promoted | |
388 // in the total; otherwise the next young gen GC will simply bail out to a | |
389 // full GC. | |
390 const size_t alignment = old_gen->virtual_space()->alignment(); | |
391 const size_t eden_used = eden_space->used_in_bytes(); | |
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392 const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average(); |
0 | 393 const size_t absorb_size = align_size_up(eden_used + promoted, alignment); |
394 const size_t eden_capacity = eden_space->capacity_in_bytes(); | |
395 | |
396 if (absorb_size >= eden_capacity) { | |
397 return false; // Must leave some space in eden. | |
398 } | |
399 | |
400 const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size; | |
401 if (new_young_size < young_gen->min_gen_size()) { | |
402 return false; // Respect young gen minimum size. | |
403 } | |
404 | |
405 if (TraceAdaptiveGCBoundary && Verbose) { | |
406 gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: " | |
407 "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K " | |
408 "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K " | |
409 "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ", | |
410 absorb_size / K, | |
411 eden_capacity / K, (eden_capacity - absorb_size) / K, | |
412 young_gen->from_space()->used_in_bytes() / K, | |
413 young_gen->to_space()->used_in_bytes() / K, | |
414 young_gen->capacity_in_bytes() / K, new_young_size / K); | |
415 } | |
416 | |
417 // Fill the unused part of the old gen. | |
418 MutableSpace* const old_space = old_gen->object_space(); | |
481
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419 HeapWord* const unused_start = old_space->top(); |
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420 size_t const unused_words = pointer_delta(old_space->end(), unused_start); |
0 | 421 |
481
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422 if (unused_words > 0) { |
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423 if (unused_words < CollectedHeap::min_fill_size()) { |
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424 return false; // If the old gen cannot be filled, must give up. |
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425 } |
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426 CollectedHeap::fill_with_objects(unused_start, unused_words); |
0 | 427 } |
428 | |
429 // Take the live data from eden and set both top and end in the old gen to | |
430 // eden top. (Need to set end because reset_after_change() mangles the region | |
431 // from end to virtual_space->high() in debug builds). | |
432 HeapWord* const new_top = eden_space->top(); | |
433 old_gen->virtual_space()->expand_into(young_gen->virtual_space(), | |
434 absorb_size); | |
435 young_gen->reset_after_change(); | |
436 old_space->set_top(new_top); | |
437 old_space->set_end(new_top); | |
438 old_gen->reset_after_change(); | |
439 | |
440 // Update the object start array for the filler object and the data from eden. | |
441 ObjectStartArray* const start_array = old_gen->start_array(); | |
481
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442 for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) { |
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443 start_array->allocate_block(p); |
0 | 444 } |
445 | |
446 // Could update the promoted average here, but it is not typically updated at | |
447 // full GCs and the value to use is unclear. Something like | |
448 // | |
449 // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc. | |
450 | |
451 size_policy->set_bytes_absorbed_from_eden(absorb_size); | |
452 return true; | |
453 } | |
454 | |
455 void PSMarkSweep::allocate_stacks() { | |
456 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
457 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
458 | |
459 PSYoungGen* young_gen = heap->young_gen(); | |
460 | |
461 MutableSpace* to_space = young_gen->to_space(); | |
462 _preserved_marks = (PreservedMark*)to_space->top(); | |
463 _preserved_count = 0; | |
464 | |
465 // We want to calculate the size in bytes first. | |
466 _preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte)); | |
467 // Now divide by the size of a PreservedMark | |
468 _preserved_count_max /= sizeof(PreservedMark); | |
469 | |
470 _preserved_mark_stack = NULL; | |
471 _preserved_oop_stack = NULL; | |
472 | |
473 _marking_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true); | |
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474 _objarray_stack = new (ResourceObj::C_HEAP) GrowableArray<ObjArrayTask>(50, true); |
0 | 475 |
476 int size = SystemDictionary::number_of_classes() * 2; | |
477 _revisit_klass_stack = new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true); | |
941 | 478 // (#klass/k)^2, for k ~ 10 appears a better setting, but this will have to do for |
479 // now until we investigate a more optimal setting. | |
480 _revisit_mdo_stack = new (ResourceObj::C_HEAP) GrowableArray<DataLayout*>(size*2, true); | |
0 | 481 } |
482 | |
483 | |
484 void PSMarkSweep::deallocate_stacks() { | |
485 if (_preserved_oop_stack) { | |
486 delete _preserved_mark_stack; | |
487 _preserved_mark_stack = NULL; | |
488 delete _preserved_oop_stack; | |
489 _preserved_oop_stack = NULL; | |
490 } | |
491 | |
492 delete _marking_stack; | |
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493 delete _objarray_stack; |
0 | 494 delete _revisit_klass_stack; |
941 | 495 delete _revisit_mdo_stack; |
0 | 496 } |
497 | |
498 void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) { | |
499 // Recursively traverse all live objects and mark them | |
500 EventMark m("1 mark object"); | |
501 TraceTime tm("phase 1", PrintGCDetails && Verbose, true, gclog_or_tty); | |
502 trace(" 1"); | |
503 | |
504 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
505 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
506 | |
507 // General strong roots. | |
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508 { |
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509 ParallelScavengeHeap::ParStrongRootsScope psrs; |
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510 Universe::oops_do(mark_and_push_closure()); |
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511 ReferenceProcessor::oops_do(mark_and_push_closure()); |
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512 JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles |
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513 CodeBlobToOopClosure each_active_code_blob(mark_and_push_closure(), /*do_marking=*/ true); |
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514 Threads::oops_do(mark_and_push_closure(), &each_active_code_blob); |
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515 ObjectSynchronizer::oops_do(mark_and_push_closure()); |
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516 FlatProfiler::oops_do(mark_and_push_closure()); |
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517 Management::oops_do(mark_and_push_closure()); |
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518 JvmtiExport::oops_do(mark_and_push_closure()); |
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519 SystemDictionary::always_strong_oops_do(mark_and_push_closure()); |
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520 vmSymbols::oops_do(mark_and_push_closure()); |
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521 // Do not treat nmethods as strong roots for mark/sweep, since we can unload them. |
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522 //CodeCache::scavenge_root_nmethods_do(CodeBlobToOopClosure(mark_and_push_closure())); |
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523 } |
0 | 524 |
525 // Flush marking stack. | |
526 follow_stack(); | |
527 | |
528 // Process reference objects found during marking | |
529 { | |
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530 ref_processor()->setup_policy(clear_all_softrefs); |
0 | 531 ref_processor()->process_discovered_references( |
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532 is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL); |
0 | 533 } |
534 | |
535 // Follow system dictionary roots and unload classes | |
536 bool purged_class = SystemDictionary::do_unloading(is_alive_closure()); | |
537 | |
538 // Follow code cache roots | |
539 CodeCache::do_unloading(is_alive_closure(), mark_and_push_closure(), | |
540 purged_class); | |
541 follow_stack(); // Flush marking stack | |
542 | |
543 // Update subklass/sibling/implementor links of live klasses | |
544 follow_weak_klass_links(); | |
545 assert(_marking_stack->is_empty(), "just drained"); | |
546 | |
941 | 547 // Visit memoized mdo's and clear unmarked weak refs |
548 follow_mdo_weak_refs(); | |
549 assert(_marking_stack->is_empty(), "just drained"); | |
550 | |
0 | 551 // Visit symbol and interned string tables and delete unmarked oops |
552 SymbolTable::unlink(is_alive_closure()); | |
553 StringTable::unlink(is_alive_closure()); | |
554 | |
555 assert(_marking_stack->is_empty(), "stack should be empty by now"); | |
556 } | |
557 | |
558 | |
559 void PSMarkSweep::mark_sweep_phase2() { | |
560 EventMark m("2 compute new addresses"); | |
561 TraceTime tm("phase 2", PrintGCDetails && Verbose, true, gclog_or_tty); | |
562 trace("2"); | |
563 | |
564 // Now all live objects are marked, compute the new object addresses. | |
565 | |
566 // It is imperative that we traverse perm_gen LAST. If dead space is | |
567 // allowed a range of dead object may get overwritten by a dead int | |
568 // array. If perm_gen is not traversed last a klassOop may get | |
569 // overwritten. This is fine since it is dead, but if the class has dead | |
570 // instances we have to skip them, and in order to find their size we | |
571 // need the klassOop! | |
572 // | |
573 // It is not required that we traverse spaces in the same order in | |
574 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops | |
575 // tracking expects us to do so. See comment under phase4. | |
576 | |
577 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
578 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
579 | |
580 PSOldGen* old_gen = heap->old_gen(); | |
581 PSPermGen* perm_gen = heap->perm_gen(); | |
582 | |
583 // Begin compacting into the old gen | |
584 PSMarkSweepDecorator::set_destination_decorator_tenured(); | |
585 | |
586 // This will also compact the young gen spaces. | |
587 old_gen->precompact(); | |
588 | |
589 // Compact the perm gen into the perm gen | |
590 PSMarkSweepDecorator::set_destination_decorator_perm_gen(); | |
591 | |
592 perm_gen->precompact(); | |
593 } | |
594 | |
595 // This should be moved to the shared markSweep code! | |
596 class PSAlwaysTrueClosure: public BoolObjectClosure { | |
597 public: | |
598 void do_object(oop p) { ShouldNotReachHere(); } | |
599 bool do_object_b(oop p) { return true; } | |
600 }; | |
601 static PSAlwaysTrueClosure always_true; | |
602 | |
603 void PSMarkSweep::mark_sweep_phase3() { | |
604 // Adjust the pointers to reflect the new locations | |
605 EventMark m("3 adjust pointers"); | |
606 TraceTime tm("phase 3", PrintGCDetails && Verbose, true, gclog_or_tty); | |
607 trace("3"); | |
608 | |
609 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
610 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
611 | |
612 PSYoungGen* young_gen = heap->young_gen(); | |
613 PSOldGen* old_gen = heap->old_gen(); | |
614 PSPermGen* perm_gen = heap->perm_gen(); | |
615 | |
616 // General strong roots. | |
617 Universe::oops_do(adjust_root_pointer_closure()); | |
618 ReferenceProcessor::oops_do(adjust_root_pointer_closure()); | |
619 JNIHandles::oops_do(adjust_root_pointer_closure()); // Global (strong) JNI handles | |
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620 Threads::oops_do(adjust_root_pointer_closure(), NULL); |
0 | 621 ObjectSynchronizer::oops_do(adjust_root_pointer_closure()); |
622 FlatProfiler::oops_do(adjust_root_pointer_closure()); | |
623 Management::oops_do(adjust_root_pointer_closure()); | |
624 JvmtiExport::oops_do(adjust_root_pointer_closure()); | |
625 // SO_AllClasses | |
626 SystemDictionary::oops_do(adjust_root_pointer_closure()); | |
627 vmSymbols::oops_do(adjust_root_pointer_closure()); | |
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628 //CodeCache::scavenge_root_nmethods_oops_do(adjust_root_pointer_closure()); |
0 | 629 |
630 // Now adjust pointers in remaining weak roots. (All of which should | |
631 // have been cleared if they pointed to non-surviving objects.) | |
632 // Global (weak) JNI handles | |
633 JNIHandles::weak_oops_do(&always_true, adjust_root_pointer_closure()); | |
634 | |
635 CodeCache::oops_do(adjust_pointer_closure()); | |
636 SymbolTable::oops_do(adjust_root_pointer_closure()); | |
637 StringTable::oops_do(adjust_root_pointer_closure()); | |
638 ref_processor()->weak_oops_do(adjust_root_pointer_closure()); | |
639 PSScavenge::reference_processor()->weak_oops_do(adjust_root_pointer_closure()); | |
640 | |
641 adjust_marks(); | |
642 | |
643 young_gen->adjust_pointers(); | |
644 old_gen->adjust_pointers(); | |
645 perm_gen->adjust_pointers(); | |
646 } | |
647 | |
648 void PSMarkSweep::mark_sweep_phase4() { | |
649 EventMark m("4 compact heap"); | |
650 TraceTime tm("phase 4", PrintGCDetails && Verbose, true, gclog_or_tty); | |
651 trace("4"); | |
652 | |
653 // All pointers are now adjusted, move objects accordingly | |
654 | |
655 // It is imperative that we traverse perm_gen first in phase4. All | |
656 // classes must be allocated earlier than their instances, and traversing | |
657 // perm_gen first makes sure that all klassOops have moved to their new | |
658 // location before any instance does a dispatch through it's klass! | |
659 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
660 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
661 | |
662 PSYoungGen* young_gen = heap->young_gen(); | |
663 PSOldGen* old_gen = heap->old_gen(); | |
664 PSPermGen* perm_gen = heap->perm_gen(); | |
665 | |
666 perm_gen->compact(); | |
667 old_gen->compact(); | |
668 young_gen->compact(); | |
669 } | |
670 | |
671 jlong PSMarkSweep::millis_since_last_gc() { | |
672 jlong ret_val = os::javaTimeMillis() - _time_of_last_gc; | |
673 // XXX See note in genCollectedHeap::millis_since_last_gc(). | |
674 if (ret_val < 0) { | |
675 NOT_PRODUCT(warning("time warp: %d", ret_val);) | |
676 return 0; | |
677 } | |
678 return ret_val; | |
679 } | |
680 | |
681 void PSMarkSweep::reset_millis_since_last_gc() { | |
682 _time_of_last_gc = os::javaTimeMillis(); | |
683 } |