Mercurial > hg > graal-jvmci-8
comparison src/share/vm/gc_implementation/g1/g1MarkSweep.cpp @ 342:37f87013dfd8
6711316: Open source the Garbage-First garbage collector
Summary: First mercurial integration of the code for the Garbage-First garbage collector.
Reviewed-by: apetrusenko, iveresov, jmasa, sgoldman, tonyp, ysr
author | ysr |
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date | Thu, 05 Jun 2008 15:57:56 -0700 |
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children | 8651a65ac4b4 |
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1 /* | |
2 * Copyright 2001-2007 Sun Microsystems, Inc. All Rights Reserved. | |
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/_g1MarkSweep.cpp.incl" | |
27 | |
28 class HeapRegion; | |
29 | |
30 void G1MarkSweep::invoke_at_safepoint(ReferenceProcessor* rp, | |
31 bool clear_all_softrefs) { | |
32 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); | |
33 | |
34 // hook up weak ref data so it can be used during Mark-Sweep | |
35 assert(GenMarkSweep::ref_processor() == NULL, "no stomping"); | |
36 GenMarkSweep::_ref_processor = rp; | |
37 assert(rp != NULL, "should be non-NULL"); | |
38 | |
39 // When collecting the permanent generation methodOops may be moving, | |
40 // so we either have to flush all bcp data or convert it into bci. | |
41 CodeCache::gc_prologue(); | |
42 Threads::gc_prologue(); | |
43 | |
44 // Increment the invocation count for the permanent generation, since it is | |
45 // implicitly collected whenever we do a full mark sweep collection. | |
46 SharedHeap* sh = SharedHeap::heap(); | |
47 sh->perm_gen()->stat_record()->invocations++; | |
48 | |
49 bool marked_for_unloading = false; | |
50 | |
51 allocate_stacks(); | |
52 | |
53 mark_sweep_phase1(marked_for_unloading, clear_all_softrefs); | |
54 | |
55 if (G1VerifyConcMark) { | |
56 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
57 g1h->checkConcurrentMark(); | |
58 } | |
59 | |
60 mark_sweep_phase2(); | |
61 | |
62 // Don't add any more derived pointers during phase3 | |
63 COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); | |
64 | |
65 mark_sweep_phase3(); | |
66 | |
67 mark_sweep_phase4(); | |
68 | |
69 GenMarkSweep::restore_marks(); | |
70 | |
71 GenMarkSweep::deallocate_stacks(); | |
72 | |
73 // We must invalidate the perm-gen rs, so that it gets rebuilt. | |
74 GenRemSet* rs = sh->rem_set(); | |
75 rs->invalidate(sh->perm_gen()->used_region(), true /*whole_heap*/); | |
76 | |
77 // "free at last gc" is calculated from these. | |
78 // CHF: cheating for now!!! | |
79 // Universe::set_heap_capacity_at_last_gc(Universe::heap()->capacity()); | |
80 // Universe::set_heap_used_at_last_gc(Universe::heap()->used()); | |
81 | |
82 Threads::gc_epilogue(); | |
83 CodeCache::gc_epilogue(); | |
84 | |
85 // refs processing: clean slate | |
86 GenMarkSweep::_ref_processor = NULL; | |
87 } | |
88 | |
89 | |
90 void G1MarkSweep::allocate_stacks() { | |
91 GenMarkSweep::_preserved_count_max = 0; | |
92 GenMarkSweep::_preserved_marks = NULL; | |
93 GenMarkSweep::_preserved_count = 0; | |
94 GenMarkSweep::_preserved_mark_stack = NULL; | |
95 GenMarkSweep::_preserved_oop_stack = NULL; | |
96 | |
97 GenMarkSweep::_marking_stack = | |
98 new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true); | |
99 | |
100 size_t size = SystemDictionary::number_of_classes() * 2; | |
101 GenMarkSweep::_revisit_klass_stack = | |
102 new (ResourceObj::C_HEAP) GrowableArray<Klass*>((int)size, true); | |
103 } | |
104 | |
105 void G1MarkSweep::mark_sweep_phase1(bool& marked_for_unloading, | |
106 bool clear_all_softrefs) { | |
107 // Recursively traverse all live objects and mark them | |
108 EventMark m("1 mark object"); | |
109 TraceTime tm("phase 1", PrintGC && Verbose, true, gclog_or_tty); | |
110 GenMarkSweep::trace(" 1"); | |
111 | |
112 SharedHeap* sh = SharedHeap::heap(); | |
113 | |
114 sh->process_strong_roots(true, // Collecting permanent generation. | |
115 SharedHeap::SO_SystemClasses, | |
116 &GenMarkSweep::follow_root_closure, | |
117 &GenMarkSweep::follow_root_closure); | |
118 | |
119 // Process reference objects found during marking | |
120 ReferencePolicy *soft_ref_policy; | |
121 if (clear_all_softrefs) { | |
122 soft_ref_policy = new AlwaysClearPolicy(); | |
123 } else { | |
124 #ifdef COMPILER2 | |
125 soft_ref_policy = new LRUMaxHeapPolicy(); | |
126 #else | |
127 soft_ref_policy = new LRUCurrentHeapPolicy(); | |
128 #endif | |
129 } | |
130 assert(soft_ref_policy != NULL,"No soft reference policy"); | |
131 GenMarkSweep::ref_processor()->process_discovered_references( | |
132 soft_ref_policy, | |
133 &GenMarkSweep::is_alive, | |
134 &GenMarkSweep::keep_alive, | |
135 &GenMarkSweep::follow_stack_closure, | |
136 NULL); | |
137 | |
138 // Follow system dictionary roots and unload classes | |
139 bool purged_class = SystemDictionary::do_unloading(&GenMarkSweep::is_alive); | |
140 assert(GenMarkSweep::_marking_stack->is_empty(), | |
141 "stack should be empty by now"); | |
142 | |
143 // Follow code cache roots (has to be done after system dictionary, | |
144 // assumes all live klasses are marked) | |
145 CodeCache::do_unloading(&GenMarkSweep::is_alive, | |
146 &GenMarkSweep::keep_alive, | |
147 purged_class); | |
148 GenMarkSweep::follow_stack(); | |
149 | |
150 // Update subklass/sibling/implementor links of live klasses | |
151 GenMarkSweep::follow_weak_klass_links(); | |
152 assert(GenMarkSweep::_marking_stack->is_empty(), | |
153 "stack should be empty by now"); | |
154 | |
155 // Visit symbol and interned string tables and delete unmarked oops | |
156 SymbolTable::unlink(&GenMarkSweep::is_alive); | |
157 StringTable::unlink(&GenMarkSweep::is_alive); | |
158 | |
159 assert(GenMarkSweep::_marking_stack->is_empty(), | |
160 "stack should be empty by now"); | |
161 } | |
162 | |
163 class G1PrepareCompactClosure: public HeapRegionClosure { | |
164 ModRefBarrierSet* _mrbs; | |
165 CompactPoint _cp; | |
166 bool _popular_only; | |
167 | |
168 void free_humongous_region(HeapRegion* hr) { | |
169 HeapWord* bot = hr->bottom(); | |
170 HeapWord* end = hr->end(); | |
171 assert(hr->startsHumongous(), | |
172 "Only the start of a humongous region should be freed."); | |
173 G1CollectedHeap::heap()->free_region(hr); | |
174 hr->prepare_for_compaction(&_cp); | |
175 // Also clear the part of the card table that will be unused after | |
176 // compaction. | |
177 _mrbs->clear(MemRegion(hr->compaction_top(), hr->end())); | |
178 } | |
179 | |
180 public: | |
181 G1PrepareCompactClosure(CompactibleSpace* cs, bool popular_only) : | |
182 _cp(NULL, cs, cs->initialize_threshold()), | |
183 _mrbs(G1CollectedHeap::heap()->mr_bs()), | |
184 _popular_only(popular_only) | |
185 {} | |
186 bool doHeapRegion(HeapRegion* hr) { | |
187 if (_popular_only && !hr->popular()) | |
188 return true; // terminate early | |
189 else if (!_popular_only && hr->popular()) | |
190 return false; // skip this one. | |
191 | |
192 if (hr->isHumongous()) { | |
193 if (hr->startsHumongous()) { | |
194 oop obj = oop(hr->bottom()); | |
195 if (obj->is_gc_marked()) { | |
196 obj->forward_to(obj); | |
197 } else { | |
198 free_humongous_region(hr); | |
199 } | |
200 } else { | |
201 assert(hr->continuesHumongous(), "Invalid humongous."); | |
202 } | |
203 } else { | |
204 hr->prepare_for_compaction(&_cp); | |
205 // Also clear the part of the card table that will be unused after | |
206 // compaction. | |
207 _mrbs->clear(MemRegion(hr->compaction_top(), hr->end())); | |
208 } | |
209 return false; | |
210 } | |
211 }; | |
212 // Stolen verbatim from g1CollectedHeap.cpp | |
213 class FindFirstRegionClosure: public HeapRegionClosure { | |
214 HeapRegion* _a_region; | |
215 bool _find_popular; | |
216 public: | |
217 FindFirstRegionClosure(bool find_popular) : | |
218 _a_region(NULL), _find_popular(find_popular) {} | |
219 bool doHeapRegion(HeapRegion* r) { | |
220 if (r->popular() == _find_popular) { | |
221 _a_region = r; | |
222 return true; | |
223 } else { | |
224 return false; | |
225 } | |
226 } | |
227 HeapRegion* result() { return _a_region; } | |
228 }; | |
229 | |
230 void G1MarkSweep::mark_sweep_phase2() { | |
231 // Now all live objects are marked, compute the new object addresses. | |
232 | |
233 // It is imperative that we traverse perm_gen LAST. If dead space is | |
234 // allowed a range of dead object may get overwritten by a dead int | |
235 // array. If perm_gen is not traversed last a klassOop may get | |
236 // overwritten. This is fine since it is dead, but if the class has dead | |
237 // instances we have to skip them, and in order to find their size we | |
238 // need the klassOop! | |
239 // | |
240 // It is not required that we traverse spaces in the same order in | |
241 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops | |
242 // tracking expects us to do so. See comment under phase4. | |
243 | |
244 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
245 Generation* pg = g1h->perm_gen(); | |
246 | |
247 EventMark m("2 compute new addresses"); | |
248 TraceTime tm("phase 2", PrintGC && Verbose, true, gclog_or_tty); | |
249 GenMarkSweep::trace("2"); | |
250 | |
251 // First we compact the popular regions. | |
252 if (G1NumPopularRegions > 0) { | |
253 CompactibleSpace* sp = g1h->first_compactible_space(); | |
254 FindFirstRegionClosure cl(true /*find_popular*/); | |
255 g1h->heap_region_iterate(&cl); | |
256 HeapRegion *r = cl.result(); | |
257 assert(r->popular(), "should have found a popular region."); | |
258 assert(r == sp, "first popular heap region should " | |
259 "== first compactible space"); | |
260 G1PrepareCompactClosure blk(sp, true/*popular_only*/); | |
261 g1h->heap_region_iterate(&blk); | |
262 } | |
263 | |
264 // Now we do the regular regions. | |
265 FindFirstRegionClosure cl(false /*find_popular*/); | |
266 g1h->heap_region_iterate(&cl); | |
267 HeapRegion *r = cl.result(); | |
268 assert(!r->popular(), "should have founda non-popular region."); | |
269 CompactibleSpace* sp = r; | |
270 if (r->isHumongous() && oop(r->bottom())->is_gc_marked()) { | |
271 sp = r->next_compaction_space(); | |
272 } | |
273 | |
274 G1PrepareCompactClosure blk(sp, false/*popular_only*/); | |
275 g1h->heap_region_iterate(&blk); | |
276 | |
277 CompactPoint perm_cp(pg, NULL, NULL); | |
278 pg->prepare_for_compaction(&perm_cp); | |
279 } | |
280 | |
281 class G1AdjustPointersClosure: public HeapRegionClosure { | |
282 public: | |
283 bool doHeapRegion(HeapRegion* r) { | |
284 if (r->isHumongous()) { | |
285 if (r->startsHumongous()) { | |
286 // We must adjust the pointers on the single H object. | |
287 oop obj = oop(r->bottom()); | |
288 debug_only(GenMarkSweep::track_interior_pointers(obj)); | |
289 // point all the oops to the new location | |
290 obj->adjust_pointers(); | |
291 debug_only(GenMarkSweep::check_interior_pointers()); | |
292 } | |
293 } else { | |
294 // This really ought to be "as_CompactibleSpace"... | |
295 r->adjust_pointers(); | |
296 } | |
297 return false; | |
298 } | |
299 }; | |
300 | |
301 void G1MarkSweep::mark_sweep_phase3() { | |
302 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
303 Generation* pg = g1h->perm_gen(); | |
304 | |
305 // Adjust the pointers to reflect the new locations | |
306 EventMark m("3 adjust pointers"); | |
307 TraceTime tm("phase 3", PrintGC && Verbose, true, gclog_or_tty); | |
308 GenMarkSweep::trace("3"); | |
309 | |
310 SharedHeap* sh = SharedHeap::heap(); | |
311 | |
312 sh->process_strong_roots(true, // Collecting permanent generation. | |
313 SharedHeap::SO_AllClasses, | |
314 &GenMarkSweep::adjust_root_pointer_closure, | |
315 &GenMarkSweep::adjust_pointer_closure); | |
316 | |
317 g1h->ref_processor()->weak_oops_do(&GenMarkSweep::adjust_root_pointer_closure); | |
318 | |
319 // Now adjust pointers in remaining weak roots. (All of which should | |
320 // have been cleared if they pointed to non-surviving objects.) | |
321 g1h->g1_process_weak_roots(&GenMarkSweep::adjust_root_pointer_closure, | |
322 &GenMarkSweep::adjust_pointer_closure); | |
323 | |
324 GenMarkSweep::adjust_marks(); | |
325 | |
326 G1AdjustPointersClosure blk; | |
327 g1h->heap_region_iterate(&blk); | |
328 pg->adjust_pointers(); | |
329 } | |
330 | |
331 class G1SpaceCompactClosure: public HeapRegionClosure { | |
332 public: | |
333 G1SpaceCompactClosure() {} | |
334 | |
335 bool doHeapRegion(HeapRegion* hr) { | |
336 if (hr->isHumongous()) { | |
337 if (hr->startsHumongous()) { | |
338 oop obj = oop(hr->bottom()); | |
339 if (obj->is_gc_marked()) { | |
340 obj->init_mark(); | |
341 } else { | |
342 assert(hr->is_empty(), "Should have been cleared in phase 2."); | |
343 } | |
344 hr->reset_during_compaction(); | |
345 } | |
346 } else { | |
347 hr->compact(); | |
348 } | |
349 return false; | |
350 } | |
351 }; | |
352 | |
353 void G1MarkSweep::mark_sweep_phase4() { | |
354 // All pointers are now adjusted, move objects accordingly | |
355 | |
356 // It is imperative that we traverse perm_gen first in phase4. All | |
357 // classes must be allocated earlier than their instances, and traversing | |
358 // perm_gen first makes sure that all klassOops have moved to their new | |
359 // location before any instance does a dispatch through it's klass! | |
360 | |
361 // The ValidateMarkSweep live oops tracking expects us to traverse spaces | |
362 // in the same order in phase2, phase3 and phase4. We don't quite do that | |
363 // here (perm_gen first rather than last), so we tell the validate code | |
364 // to use a higher index (saved from phase2) when verifying perm_gen. | |
365 G1CollectedHeap* g1h = G1CollectedHeap::heap(); | |
366 Generation* pg = g1h->perm_gen(); | |
367 | |
368 EventMark m("4 compact heap"); | |
369 TraceTime tm("phase 4", PrintGC && Verbose, true, gclog_or_tty); | |
370 GenMarkSweep::trace("4"); | |
371 | |
372 pg->compact(); | |
373 | |
374 G1SpaceCompactClosure blk; | |
375 g1h->heap_region_iterate(&blk); | |
376 | |
377 } | |
378 | |
379 // Local Variables: *** | |
380 // c-indentation-style: gnu *** | |
381 // End: *** |