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annotate src/share/vm/gc_implementation/g1/g1MarkSweep.cpp @ 3687:7958ebb561b0
Merge
author | Lukas Stadler <lukas.stadler@jku.at> |
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date | Fri, 18 Nov 2011 17:20:38 +0100 |
parents | 1216415d8e35 |
children | 6747fd0512e0 |
rev | line source |
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342 | 1 /* |
2152 | 2 * Copyright (c) 2001, 2011, Oracle and/or its affiliates. All rights reserved. |
342 | 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 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
342 | 22 * |
23 */ | |
24 | |
1972 | 25 #include "precompiled.hpp" |
26 #include "classfile/javaClasses.hpp" | |
27 #include "classfile/symbolTable.hpp" | |
28 #include "classfile/systemDictionary.hpp" | |
29 #include "classfile/vmSymbols.hpp" | |
30 #include "code/codeCache.hpp" | |
31 #include "code/icBuffer.hpp" | |
32 #include "gc_implementation/g1/g1MarkSweep.hpp" | |
33 #include "memory/gcLocker.hpp" | |
34 #include "memory/genCollectedHeap.hpp" | |
35 #include "memory/modRefBarrierSet.hpp" | |
36 #include "memory/referencePolicy.hpp" | |
37 #include "memory/space.hpp" | |
38 #include "oops/instanceRefKlass.hpp" | |
39 #include "oops/oop.inline.hpp" | |
40 #include "prims/jvmtiExport.hpp" | |
41 #include "runtime/aprofiler.hpp" | |
42 #include "runtime/biasedLocking.hpp" | |
43 #include "runtime/fprofiler.hpp" | |
44 #include "runtime/synchronizer.hpp" | |
45 #include "runtime/thread.hpp" | |
46 #include "runtime/vmThread.hpp" | |
47 #include "utilities/copy.hpp" | |
48 #include "utilities/events.hpp" | |
342 | 49 |
50 class HeapRegion; | |
51 | |
52 void G1MarkSweep::invoke_at_safepoint(ReferenceProcessor* rp, | |
53 bool clear_all_softrefs) { | |
54 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); | |
55 | |
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56 SharedHeap* sh = SharedHeap::heap(); |
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57 #ifdef ASSERT |
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58 if (sh->collector_policy()->should_clear_all_soft_refs()) { |
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59 assert(clear_all_softrefs, "Policy should have been checked earler"); |
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60 } |
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61 #endif |
342 | 62 // hook up weak ref data so it can be used during Mark-Sweep |
63 assert(GenMarkSweep::ref_processor() == NULL, "no stomping"); | |
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64 assert(rp != NULL, "should be non-NULL"); |
342 | 65 GenMarkSweep::_ref_processor = rp; |
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66 rp->setup_policy(clear_all_softrefs); |
342 | 67 |
68 // When collecting the permanent generation methodOops may be moving, | |
69 // so we either have to flush all bcp data or convert it into bci. | |
70 CodeCache::gc_prologue(); | |
71 Threads::gc_prologue(); | |
72 | |
73 // Increment the invocation count for the permanent generation, since it is | |
74 // implicitly collected whenever we do a full mark sweep collection. | |
75 sh->perm_gen()->stat_record()->invocations++; | |
76 | |
77 bool marked_for_unloading = false; | |
78 | |
79 allocate_stacks(); | |
80 | |
358
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81 // We should save the marks of the currently locked biased monitors. |
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82 // The marking doesn't preserve the marks of biased objects. |
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83 BiasedLocking::preserve_marks(); |
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84 |
342 | 85 mark_sweep_phase1(marked_for_unloading, clear_all_softrefs); |
86 | |
751 | 87 if (VerifyDuringGC) { |
342 | 88 G1CollectedHeap* g1h = G1CollectedHeap::heap(); |
89 g1h->checkConcurrentMark(); | |
90 } | |
91 | |
92 mark_sweep_phase2(); | |
93 | |
94 // Don't add any more derived pointers during phase3 | |
95 COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); | |
96 | |
97 mark_sweep_phase3(); | |
98 | |
99 mark_sweep_phase4(); | |
100 | |
101 GenMarkSweep::restore_marks(); | |
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102 BiasedLocking::restore_marks(); |
342 | 103 GenMarkSweep::deallocate_stacks(); |
104 | |
105 // We must invalidate the perm-gen rs, so that it gets rebuilt. | |
106 GenRemSet* rs = sh->rem_set(); | |
107 rs->invalidate(sh->perm_gen()->used_region(), true /*whole_heap*/); | |
108 | |
109 // "free at last gc" is calculated from these. | |
110 // CHF: cheating for now!!! | |
111 // Universe::set_heap_capacity_at_last_gc(Universe::heap()->capacity()); | |
112 // Universe::set_heap_used_at_last_gc(Universe::heap()->used()); | |
113 | |
114 Threads::gc_epilogue(); | |
115 CodeCache::gc_epilogue(); | |
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116 JvmtiExport::gc_epilogue(); |
342 | 117 |
118 // refs processing: clean slate | |
119 GenMarkSweep::_ref_processor = NULL; | |
120 } | |
121 | |
122 | |
123 void G1MarkSweep::allocate_stacks() { | |
124 GenMarkSweep::_preserved_count_max = 0; | |
125 GenMarkSweep::_preserved_marks = NULL; | |
126 GenMarkSweep::_preserved_count = 0; | |
127 } | |
128 | |
129 void G1MarkSweep::mark_sweep_phase1(bool& marked_for_unloading, | |
130 bool clear_all_softrefs) { | |
131 // Recursively traverse all live objects and mark them | |
132 EventMark m("1 mark object"); | |
133 TraceTime tm("phase 1", PrintGC && Verbose, true, gclog_or_tty); | |
134 GenMarkSweep::trace(" 1"); | |
135 | |
136 SharedHeap* sh = SharedHeap::heap(); | |
137 | |
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138 sh->process_strong_roots(true, // activeate StrongRootsScope |
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139 true, // Collecting permanent generation. |
342 | 140 SharedHeap::SO_SystemClasses, |
141 &GenMarkSweep::follow_root_closure, | |
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142 &GenMarkSweep::follow_code_root_closure, |
342 | 143 &GenMarkSweep::follow_root_closure); |
144 | |
145 // Process reference objects found during marking | |
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146 ReferenceProcessor* rp = GenMarkSweep::ref_processor(); |
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147 rp->setup_policy(clear_all_softrefs); |
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148 rp->process_discovered_references(&GenMarkSweep::is_alive, |
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149 &GenMarkSweep::keep_alive, |
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150 &GenMarkSweep::follow_stack_closure, |
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151 NULL); |
342 | 152 |
153 // Follow system dictionary roots and unload classes | |
154 bool purged_class = SystemDictionary::do_unloading(&GenMarkSweep::is_alive); | |
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155 assert(GenMarkSweep::_marking_stack.is_empty(), |
342 | 156 "stack should be empty by now"); |
157 | |
158 // Follow code cache roots (has to be done after system dictionary, | |
159 // assumes all live klasses are marked) | |
160 CodeCache::do_unloading(&GenMarkSweep::is_alive, | |
161 &GenMarkSweep::keep_alive, | |
162 purged_class); | |
941 | 163 GenMarkSweep::follow_stack(); |
342 | 164 |
165 // Update subklass/sibling/implementor links of live klasses | |
166 GenMarkSweep::follow_weak_klass_links(); | |
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167 assert(GenMarkSweep::_marking_stack.is_empty(), |
342 | 168 "stack should be empty by now"); |
169 | |
941 | 170 // Visit memoized MDO's and clear any unmarked weak refs |
171 GenMarkSweep::follow_mdo_weak_refs(); | |
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172 assert(GenMarkSweep::_marking_stack.is_empty(), "just drained"); |
941 | 173 |
174 | |
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175 // Visit interned string tables and delete unmarked oops |
342 | 176 StringTable::unlink(&GenMarkSweep::is_alive); |
2177
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177 // Clean up unreferenced symbols in symbol table. |
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178 SymbolTable::unlink(); |
342 | 179 |
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180 assert(GenMarkSweep::_marking_stack.is_empty(), |
342 | 181 "stack should be empty by now"); |
182 } | |
183 | |
184 class G1PrepareCompactClosure: public HeapRegionClosure { | |
2152 | 185 G1CollectedHeap* _g1h; |
342 | 186 ModRefBarrierSet* _mrbs; |
187 CompactPoint _cp; | |
2152 | 188 HumongousRegionSet _humongous_proxy_set; |
342 | 189 |
190 void free_humongous_region(HeapRegion* hr) { | |
191 HeapWord* end = hr->end(); | |
2361 | 192 size_t dummy_pre_used; |
193 FreeRegionList dummy_free_list("Dummy Free List for G1MarkSweep"); | |
194 | |
342 | 195 assert(hr->startsHumongous(), |
196 "Only the start of a humongous region should be freed."); | |
2361 | 197 _g1h->free_humongous_region(hr, &dummy_pre_used, &dummy_free_list, |
2152 | 198 &_humongous_proxy_set, false /* par */); |
342 | 199 hr->prepare_for_compaction(&_cp); |
200 // Also clear the part of the card table that will be unused after | |
201 // compaction. | |
2152 | 202 _mrbs->clear(MemRegion(hr->compaction_top(), end)); |
2361 | 203 dummy_free_list.remove_all(); |
342 | 204 } |
205 | |
206 public: | |
2152 | 207 G1PrepareCompactClosure(CompactibleSpace* cs) |
208 : _g1h(G1CollectedHeap::heap()), | |
209 _mrbs(G1CollectedHeap::heap()->mr_bs()), | |
342 | 210 _cp(NULL, cs, cs->initialize_threshold()), |
2152 | 211 _humongous_proxy_set("G1MarkSweep Humongous Proxy Set") { } |
212 | |
213 void update_sets() { | |
214 // We'll recalculate total used bytes and recreate the free list | |
215 // at the end of the GC, so no point in updating those values here. | |
216 _g1h->update_sets_after_freeing_regions(0, /* pre_used */ | |
217 NULL, /* free_list */ | |
218 &_humongous_proxy_set, | |
219 false /* par */); | |
220 } | |
221 | |
342 | 222 bool doHeapRegion(HeapRegion* hr) { |
223 if (hr->isHumongous()) { | |
224 if (hr->startsHumongous()) { | |
225 oop obj = oop(hr->bottom()); | |
226 if (obj->is_gc_marked()) { | |
227 obj->forward_to(obj); | |
228 } else { | |
229 free_humongous_region(hr); | |
230 } | |
231 } else { | |
232 assert(hr->continuesHumongous(), "Invalid humongous."); | |
233 } | |
234 } else { | |
235 hr->prepare_for_compaction(&_cp); | |
236 // Also clear the part of the card table that will be unused after | |
237 // compaction. | |
238 _mrbs->clear(MemRegion(hr->compaction_top(), hr->end())); | |
239 } | |
240 return false; | |
241 } | |
242 }; | |
677 | 243 |
244 // Finds the first HeapRegion. | |
342 | 245 class FindFirstRegionClosure: public HeapRegionClosure { |
246 HeapRegion* _a_region; | |
247 public: | |
677 | 248 FindFirstRegionClosure() : _a_region(NULL) {} |
342 | 249 bool doHeapRegion(HeapRegion* r) { |
677 | 250 _a_region = r; |
251 return true; | |
342 | 252 } |
253 HeapRegion* result() { return _a_region; } | |
254 }; | |
255 | |
256 void G1MarkSweep::mark_sweep_phase2() { | |
257 // Now all live objects are marked, compute the new object addresses. | |
258 | |
259 // It is imperative that we traverse perm_gen LAST. If dead space is | |
260 // allowed a range of dead object may get overwritten by a dead int | |
261 // array. If perm_gen is not traversed last a klassOop may get | |
262 // overwritten. This is fine since it is dead, but if the class has dead | |
263 // instances we have to skip them, and in order to find their size we | |
264 // need the klassOop! | |
265 // | |
266 // It is not required that we traverse spaces in the same order in | |
267 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops | |
268 // tracking expects us to do so. See comment under phase4. | |
269 | |
270 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
271 Generation* pg = g1h->perm_gen(); | |
272 | |
273 EventMark m("2 compute new addresses"); | |
274 TraceTime tm("phase 2", PrintGC && Verbose, true, gclog_or_tty); | |
275 GenMarkSweep::trace("2"); | |
276 | |
677 | 277 FindFirstRegionClosure cl; |
342 | 278 g1h->heap_region_iterate(&cl); |
279 HeapRegion *r = cl.result(); | |
280 CompactibleSpace* sp = r; | |
281 if (r->isHumongous() && oop(r->bottom())->is_gc_marked()) { | |
282 sp = r->next_compaction_space(); | |
283 } | |
284 | |
677 | 285 G1PrepareCompactClosure blk(sp); |
342 | 286 g1h->heap_region_iterate(&blk); |
2152 | 287 blk.update_sets(); |
342 | 288 |
289 CompactPoint perm_cp(pg, NULL, NULL); | |
290 pg->prepare_for_compaction(&perm_cp); | |
291 } | |
292 | |
293 class G1AdjustPointersClosure: public HeapRegionClosure { | |
294 public: | |
295 bool doHeapRegion(HeapRegion* r) { | |
296 if (r->isHumongous()) { | |
297 if (r->startsHumongous()) { | |
298 // We must adjust the pointers on the single H object. | |
299 oop obj = oop(r->bottom()); | |
300 debug_only(GenMarkSweep::track_interior_pointers(obj)); | |
301 // point all the oops to the new location | |
302 obj->adjust_pointers(); | |
303 debug_only(GenMarkSweep::check_interior_pointers()); | |
304 } | |
305 } else { | |
306 // This really ought to be "as_CompactibleSpace"... | |
307 r->adjust_pointers(); | |
308 } | |
309 return false; | |
310 } | |
311 }; | |
312 | |
313 void G1MarkSweep::mark_sweep_phase3() { | |
314 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
315 Generation* pg = g1h->perm_gen(); | |
316 | |
317 // Adjust the pointers to reflect the new locations | |
318 EventMark m("3 adjust pointers"); | |
319 TraceTime tm("phase 3", PrintGC && Verbose, true, gclog_or_tty); | |
320 GenMarkSweep::trace("3"); | |
321 | |
322 SharedHeap* sh = SharedHeap::heap(); | |
323 | |
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324 sh->process_strong_roots(true, // activate StrongRootsScope |
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325 true, // Collecting permanent generation. |
342 | 326 SharedHeap::SO_AllClasses, |
327 &GenMarkSweep::adjust_root_pointer_closure, | |
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328 NULL, // do not touch code cache here |
342 | 329 &GenMarkSweep::adjust_pointer_closure); |
330 | |
331 g1h->ref_processor()->weak_oops_do(&GenMarkSweep::adjust_root_pointer_closure); | |
332 | |
333 // Now adjust pointers in remaining weak roots. (All of which should | |
334 // have been cleared if they pointed to non-surviving objects.) | |
335 g1h->g1_process_weak_roots(&GenMarkSweep::adjust_root_pointer_closure, | |
336 &GenMarkSweep::adjust_pointer_closure); | |
337 | |
338 GenMarkSweep::adjust_marks(); | |
339 | |
340 G1AdjustPointersClosure blk; | |
341 g1h->heap_region_iterate(&blk); | |
342 pg->adjust_pointers(); | |
343 } | |
344 | |
345 class G1SpaceCompactClosure: public HeapRegionClosure { | |
346 public: | |
347 G1SpaceCompactClosure() {} | |
348 | |
349 bool doHeapRegion(HeapRegion* hr) { | |
350 if (hr->isHumongous()) { | |
351 if (hr->startsHumongous()) { | |
352 oop obj = oop(hr->bottom()); | |
353 if (obj->is_gc_marked()) { | |
354 obj->init_mark(); | |
355 } else { | |
356 assert(hr->is_empty(), "Should have been cleared in phase 2."); | |
357 } | |
358 hr->reset_during_compaction(); | |
359 } | |
360 } else { | |
361 hr->compact(); | |
362 } | |
363 return false; | |
364 } | |
365 }; | |
366 | |
367 void G1MarkSweep::mark_sweep_phase4() { | |
368 // All pointers are now adjusted, move objects accordingly | |
369 | |
370 // It is imperative that we traverse perm_gen first in phase4. All | |
371 // classes must be allocated earlier than their instances, and traversing | |
372 // perm_gen first makes sure that all klassOops have moved to their new | |
373 // location before any instance does a dispatch through it's klass! | |
374 | |
375 // The ValidateMarkSweep live oops tracking expects us to traverse spaces | |
376 // in the same order in phase2, phase3 and phase4. We don't quite do that | |
377 // here (perm_gen first rather than last), so we tell the validate code | |
378 // to use a higher index (saved from phase2) when verifying perm_gen. | |
379 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
380 Generation* pg = g1h->perm_gen(); | |
381 | |
382 EventMark m("4 compact heap"); | |
383 TraceTime tm("phase 4", PrintGC && Verbose, true, gclog_or_tty); | |
384 GenMarkSweep::trace("4"); | |
385 | |
386 pg->compact(); | |
387 | |
388 G1SpaceCompactClosure blk; | |
389 g1h->heap_region_iterate(&blk); | |
390 | |
391 } | |
392 | |
393 // Local Variables: *** | |
394 // c-indentation-style: gnu *** | |
395 // End: *** |