Mercurial > hg > graal-jvmci-8
comparison src/share/vm/memory/genMarkSweep.cpp @ 0:a61af66fc99e jdk7-b24
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author | duke |
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date | Sat, 01 Dec 2007 00:00:00 +0000 |
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children | ba764ed4b6f2 |
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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/_genMarkSweep.cpp.incl" | |
27 | |
28 void GenMarkSweep::invoke_at_safepoint(int level, ReferenceProcessor* rp, | |
29 bool clear_all_softrefs) { | |
30 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); | |
31 | |
32 // hook up weak ref data so it can be used during Mark-Sweep | |
33 assert(ref_processor() == NULL, "no stomping"); | |
34 _ref_processor = rp; | |
35 assert(rp != NULL, "should be non-NULL"); | |
36 | |
37 TraceTime t1("Full GC", PrintGC && !PrintGCDetails, true, gclog_or_tty); | |
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 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
47 gch->perm_gen()->stat_record()->invocations++; | |
48 | |
49 // Capture heap size before collection for printing. | |
50 size_t gch_prev_used = gch->used(); | |
51 | |
52 // Some of the card table updates below assume that the perm gen is | |
53 // also being collected. | |
54 assert(level == gch->n_gens() - 1, | |
55 "All generations are being collected, ergo perm gen too."); | |
56 | |
57 // Capture used regions for each generation that will be | |
58 // subject to collection, so that card table adjustments can | |
59 // be made intelligently (see clear / invalidate further below). | |
60 gch->save_used_regions(level, true /* perm */); | |
61 | |
62 allocate_stacks(); | |
63 | |
64 mark_sweep_phase1(level, clear_all_softrefs); | |
65 | |
66 mark_sweep_phase2(); | |
67 | |
68 // Don't add any more derived pointers during phase3 | |
69 COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity")); | |
70 COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); | |
71 | |
72 mark_sweep_phase3(level); | |
73 | |
74 VALIDATE_MARK_SWEEP_ONLY( | |
75 if (ValidateMarkSweep) { | |
76 guarantee(_root_refs_stack->length() == 0, | |
77 "should be empty by now"); | |
78 } | |
79 ) | |
80 | |
81 mark_sweep_phase4(); | |
82 | |
83 VALIDATE_MARK_SWEEP_ONLY( | |
84 if (ValidateMarkSweep) { | |
85 guarantee(_live_oops->length() == _live_oops_moved_to->length(), | |
86 "should be the same size"); | |
87 } | |
88 ) | |
89 | |
90 restore_marks(); | |
91 | |
92 // Set saved marks for allocation profiler (and other things? -- dld) | |
93 // (Should this be in general part?) | |
94 gch->save_marks(); | |
95 | |
96 deallocate_stacks(); | |
97 | |
98 // If compaction completely evacuated all generations younger than this | |
99 // one, then we can clear the card table. Otherwise, we must invalidate | |
100 // it (consider all cards dirty). In the future, we might consider doing | |
101 // compaction within generations only, and doing card-table sliding. | |
102 bool all_empty = true; | |
103 for (int i = 0; all_empty && i < level; i++) { | |
104 Generation* g = gch->get_gen(i); | |
105 all_empty = all_empty && gch->get_gen(i)->used() == 0; | |
106 } | |
107 GenRemSet* rs = gch->rem_set(); | |
108 // Clear/invalidate below make use of the "prev_used_regions" saved earlier. | |
109 if (all_empty) { | |
110 // We've evacuated all generations below us. | |
111 Generation* g = gch->get_gen(level); | |
112 rs->clear_into_younger(g, true /* perm */); | |
113 } else { | |
114 // Invalidate the cards corresponding to the currently used | |
115 // region and clear those corresponding to the evacuated region | |
116 // of all generations just collected (i.e. level and younger). | |
117 rs->invalidate_or_clear(gch->get_gen(level), | |
118 true /* younger */, | |
119 true /* perm */); | |
120 } | |
121 | |
122 Threads::gc_epilogue(); | |
123 CodeCache::gc_epilogue(); | |
124 | |
125 if (PrintGC && !PrintGCDetails) { | |
126 gch->print_heap_change(gch_prev_used); | |
127 } | |
128 | |
129 // refs processing: clean slate | |
130 _ref_processor = NULL; | |
131 | |
132 // Update heap occupancy information which is used as | |
133 // input to soft ref clearing policy at the next gc. | |
134 Universe::update_heap_info_at_gc(); | |
135 | |
136 // Update time of last gc for all generations we collected | |
137 // (which curently is all the generations in the heap). | |
138 gch->update_time_of_last_gc(os::javaTimeMillis()); | |
139 } | |
140 | |
141 void GenMarkSweep::allocate_stacks() { | |
142 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
143 // Scratch request on behalf of oldest generation; will do no | |
144 // allocation. | |
145 ScratchBlock* scratch = gch->gather_scratch(gch->_gens[gch->_n_gens-1], 0); | |
146 | |
147 // $$$ To cut a corner, we'll only use the first scratch block, and then | |
148 // revert to malloc. | |
149 if (scratch != NULL) { | |
150 _preserved_count_max = | |
151 scratch->num_words * HeapWordSize / sizeof(PreservedMark); | |
152 } else { | |
153 _preserved_count_max = 0; | |
154 } | |
155 | |
156 _preserved_marks = (PreservedMark*)scratch; | |
157 _preserved_count = 0; | |
158 _preserved_mark_stack = NULL; | |
159 _preserved_oop_stack = NULL; | |
160 | |
161 _marking_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true); | |
162 | |
163 int size = SystemDictionary::number_of_classes() * 2; | |
164 _revisit_klass_stack = new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true); | |
165 | |
166 #ifdef VALIDATE_MARK_SWEEP | |
167 if (ValidateMarkSweep) { | |
168 _root_refs_stack = new (ResourceObj::C_HEAP) GrowableArray<oop*>(100, true); | |
169 _other_refs_stack = new (ResourceObj::C_HEAP) GrowableArray<oop*>(100, true); | |
170 _adjusted_pointers = new (ResourceObj::C_HEAP) GrowableArray<oop*>(100, true); | |
171 _live_oops = new (ResourceObj::C_HEAP) GrowableArray<oop>(100, true); | |
172 _live_oops_moved_to = new (ResourceObj::C_HEAP) GrowableArray<oop>(100, true); | |
173 _live_oops_size = new (ResourceObj::C_HEAP) GrowableArray<size_t>(100, true); | |
174 } | |
175 if (RecordMarkSweepCompaction) { | |
176 if (_cur_gc_live_oops == NULL) { | |
177 _cur_gc_live_oops = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); | |
178 _cur_gc_live_oops_moved_to = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); | |
179 _cur_gc_live_oops_size = new(ResourceObj::C_HEAP) GrowableArray<size_t>(100, true); | |
180 _last_gc_live_oops = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); | |
181 _last_gc_live_oops_moved_to = new(ResourceObj::C_HEAP) GrowableArray<HeapWord*>(100, true); | |
182 _last_gc_live_oops_size = new(ResourceObj::C_HEAP) GrowableArray<size_t>(100, true); | |
183 } else { | |
184 _cur_gc_live_oops->clear(); | |
185 _cur_gc_live_oops_moved_to->clear(); | |
186 _cur_gc_live_oops_size->clear(); | |
187 } | |
188 } | |
189 #endif | |
190 } | |
191 | |
192 | |
193 void GenMarkSweep::deallocate_stacks() { | |
194 if (_preserved_oop_stack) { | |
195 delete _preserved_mark_stack; | |
196 _preserved_mark_stack = NULL; | |
197 delete _preserved_oop_stack; | |
198 _preserved_oop_stack = NULL; | |
199 } | |
200 | |
201 delete _marking_stack; | |
202 delete _revisit_klass_stack; | |
203 | |
204 #ifdef VALIDATE_MARK_SWEEP | |
205 if (ValidateMarkSweep) { | |
206 delete _root_refs_stack; | |
207 delete _other_refs_stack; | |
208 delete _adjusted_pointers; | |
209 delete _live_oops; | |
210 delete _live_oops_size; | |
211 delete _live_oops_moved_to; | |
212 _live_oops_index = 0; | |
213 _live_oops_index_at_perm = 0; | |
214 } | |
215 #endif | |
216 } | |
217 | |
218 void GenMarkSweep::mark_sweep_phase1(int level, | |
219 bool clear_all_softrefs) { | |
220 // Recursively traverse all live objects and mark them | |
221 EventMark m("1 mark object"); | |
222 TraceTime tm("phase 1", PrintGC && Verbose, true, gclog_or_tty); | |
223 trace(" 1"); | |
224 | |
225 VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); | |
226 | |
227 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
228 | |
229 // Because follow_root_closure is created statically, cannot | |
230 // use OopsInGenClosure constructor which takes a generation, | |
231 // as the Universe has not been created when the static constructors | |
232 // are run. | |
233 follow_root_closure.set_orig_generation(gch->get_gen(level)); | |
234 | |
235 gch->gen_process_strong_roots(level, | |
236 false, // Younger gens are not roots. | |
237 true, // Collecting permanent generation. | |
238 SharedHeap::SO_SystemClasses, | |
239 &follow_root_closure, &follow_root_closure); | |
240 | |
241 // Process reference objects found during marking | |
242 { | |
243 ReferencePolicy *soft_ref_policy; | |
244 if (clear_all_softrefs) { | |
245 soft_ref_policy = new AlwaysClearPolicy(); | |
246 } else { | |
247 #ifdef COMPILER2 | |
248 soft_ref_policy = new LRUMaxHeapPolicy(); | |
249 #else | |
250 soft_ref_policy = new LRUCurrentHeapPolicy(); | |
251 #endif // COMPILER2 | |
252 } | |
253 assert(soft_ref_policy != NULL,"No soft reference policy"); | |
254 ref_processor()->process_discovered_references( | |
255 soft_ref_policy, &is_alive, &keep_alive, | |
256 &follow_stack_closure, NULL); | |
257 } | |
258 | |
259 // Follow system dictionary roots and unload classes | |
260 bool purged_class = SystemDictionary::do_unloading(&is_alive); | |
261 | |
262 // Follow code cache roots | |
263 CodeCache::do_unloading(&is_alive, &keep_alive, purged_class); | |
264 follow_stack(); // Flush marking stack | |
265 | |
266 // Update subklass/sibling/implementor links of live klasses | |
267 follow_weak_klass_links(); | |
268 assert(_marking_stack->is_empty(), "just drained"); | |
269 | |
270 // Visit symbol and interned string tables and delete unmarked oops | |
271 SymbolTable::unlink(&is_alive); | |
272 StringTable::unlink(&is_alive); | |
273 | |
274 assert(_marking_stack->is_empty(), "stack should be empty by now"); | |
275 } | |
276 | |
277 | |
278 void GenMarkSweep::mark_sweep_phase2() { | |
279 // Now all live objects are marked, compute the new object addresses. | |
280 | |
281 // It is imperative that we traverse perm_gen LAST. If dead space is | |
282 // allowed a range of dead object may get overwritten by a dead int | |
283 // array. If perm_gen is not traversed last a klassOop may get | |
284 // overwritten. This is fine since it is dead, but if the class has dead | |
285 // instances we have to skip them, and in order to find their size we | |
286 // need the klassOop! | |
287 // | |
288 // It is not required that we traverse spaces in the same order in | |
289 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops | |
290 // tracking expects us to do so. See comment under phase4. | |
291 | |
292 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
293 Generation* pg = gch->perm_gen(); | |
294 | |
295 EventMark m("2 compute new addresses"); | |
296 TraceTime tm("phase 2", PrintGC && Verbose, true, gclog_or_tty); | |
297 trace("2"); | |
298 | |
299 VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); | |
300 | |
301 gch->prepare_for_compaction(); | |
302 | |
303 VALIDATE_MARK_SWEEP_ONLY(_live_oops_index_at_perm = _live_oops_index); | |
304 CompactPoint perm_cp(pg, NULL, NULL); | |
305 pg->prepare_for_compaction(&perm_cp); | |
306 } | |
307 | |
308 class GenAdjustPointersClosure: public GenCollectedHeap::GenClosure { | |
309 public: | |
310 void do_generation(Generation* gen) { | |
311 gen->adjust_pointers(); | |
312 } | |
313 }; | |
314 | |
315 void GenMarkSweep::mark_sweep_phase3(int level) { | |
316 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
317 Generation* pg = gch->perm_gen(); | |
318 | |
319 // Adjust the pointers to reflect the new locations | |
320 EventMark m("3 adjust pointers"); | |
321 TraceTime tm("phase 3", PrintGC && Verbose, true, gclog_or_tty); | |
322 trace("3"); | |
323 | |
324 VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); | |
325 | |
326 // Needs to be done before the system dictionary is adjusted. | |
327 pg->pre_adjust_pointers(); | |
328 | |
329 // Because the two closures below are created statically, cannot | |
330 // use OopsInGenClosure constructor which takes a generation, | |
331 // as the Universe has not been created when the static constructors | |
332 // are run. | |
333 adjust_root_pointer_closure.set_orig_generation(gch->get_gen(level)); | |
334 adjust_pointer_closure.set_orig_generation(gch->get_gen(level)); | |
335 | |
336 gch->gen_process_strong_roots(level, | |
337 false, // Younger gens are not roots. | |
338 true, // Collecting permanent generation. | |
339 SharedHeap::SO_AllClasses, | |
340 &adjust_root_pointer_closure, | |
341 &adjust_root_pointer_closure); | |
342 | |
343 // Now adjust pointers in remaining weak roots. (All of which should | |
344 // have been cleared if they pointed to non-surviving objects.) | |
345 gch->gen_process_weak_roots(&adjust_root_pointer_closure, | |
346 &adjust_pointer_closure); | |
347 | |
348 adjust_marks(); | |
349 GenAdjustPointersClosure blk; | |
350 gch->generation_iterate(&blk, true); | |
351 pg->adjust_pointers(); | |
352 } | |
353 | |
354 class GenCompactClosure: public GenCollectedHeap::GenClosure { | |
355 public: | |
356 void do_generation(Generation* gen) { | |
357 gen->compact(); | |
358 } | |
359 }; | |
360 | |
361 void GenMarkSweep::mark_sweep_phase4() { | |
362 // All pointers are now adjusted, move objects accordingly | |
363 | |
364 // It is imperative that we traverse perm_gen first in phase4. All | |
365 // classes must be allocated earlier than their instances, and traversing | |
366 // perm_gen first makes sure that all klassOops have moved to their new | |
367 // location before any instance does a dispatch through it's klass! | |
368 | |
369 // The ValidateMarkSweep live oops tracking expects us to traverse spaces | |
370 // in the same order in phase2, phase3 and phase4. We don't quite do that | |
371 // here (perm_gen first rather than last), so we tell the validate code | |
372 // to use a higher index (saved from phase2) when verifying perm_gen. | |
373 GenCollectedHeap* gch = GenCollectedHeap::heap(); | |
374 Generation* pg = gch->perm_gen(); | |
375 | |
376 EventMark m("4 compact heap"); | |
377 TraceTime tm("phase 4", PrintGC && Verbose, true, gclog_or_tty); | |
378 trace("4"); | |
379 | |
380 VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(true)); | |
381 | |
382 pg->compact(); | |
383 | |
384 VALIDATE_MARK_SWEEP_ONLY(reset_live_oop_tracking(false)); | |
385 | |
386 GenCompactClosure blk; | |
387 gch->generation_iterate(&blk, true); | |
388 | |
389 VALIDATE_MARK_SWEEP_ONLY(compaction_complete()); | |
390 | |
391 pg->post_compact(); // Shared spaces verification. | |
392 } |