Thu, 27 May 2010 19:08:38 -0700
6941466: Oracle rebranding changes for Hotspot repositories
Summary: Change all the Sun copyrights to Oracle copyright
Reviewed-by: ohair
1 /*
2 * Copyright (c) 2001, 2010, Oracle and/or its affiliates. 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 Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
25 #include "incls/_precompiled.incl"
26 #include "incls/_g1MarkSweep.cpp.incl"
28 class HeapRegion;
30 void G1MarkSweep::invoke_at_safepoint(ReferenceProcessor* rp,
31 bool clear_all_softrefs) {
32 assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint");
34 SharedHeap* sh = SharedHeap::heap();
35 #ifdef ASSERT
36 if (sh->collector_policy()->should_clear_all_soft_refs()) {
37 assert(clear_all_softrefs, "Policy should have been checked earler");
38 }
39 #endif
40 // hook up weak ref data so it can be used during Mark-Sweep
41 assert(GenMarkSweep::ref_processor() == NULL, "no stomping");
42 assert(rp != NULL, "should be non-NULL");
43 GenMarkSweep::_ref_processor = rp;
44 rp->setup_policy(clear_all_softrefs);
46 // When collecting the permanent generation methodOops may be moving,
47 // so we either have to flush all bcp data or convert it into bci.
48 CodeCache::gc_prologue();
49 Threads::gc_prologue();
51 // Increment the invocation count for the permanent generation, since it is
52 // implicitly collected whenever we do a full mark sweep collection.
53 sh->perm_gen()->stat_record()->invocations++;
55 bool marked_for_unloading = false;
57 allocate_stacks();
59 // We should save the marks of the currently locked biased monitors.
60 // The marking doesn't preserve the marks of biased objects.
61 BiasedLocking::preserve_marks();
63 mark_sweep_phase1(marked_for_unloading, clear_all_softrefs);
65 if (VerifyDuringGC) {
66 G1CollectedHeap* g1h = G1CollectedHeap::heap();
67 g1h->checkConcurrentMark();
68 }
70 mark_sweep_phase2();
72 // Don't add any more derived pointers during phase3
73 COMPILER2_PRESENT(DerivedPointerTable::set_active(false));
75 mark_sweep_phase3();
77 mark_sweep_phase4();
79 GenMarkSweep::restore_marks();
80 BiasedLocking::restore_marks();
81 GenMarkSweep::deallocate_stacks();
83 // We must invalidate the perm-gen rs, so that it gets rebuilt.
84 GenRemSet* rs = sh->rem_set();
85 rs->invalidate(sh->perm_gen()->used_region(), true /*whole_heap*/);
87 // "free at last gc" is calculated from these.
88 // CHF: cheating for now!!!
89 // Universe::set_heap_capacity_at_last_gc(Universe::heap()->capacity());
90 // Universe::set_heap_used_at_last_gc(Universe::heap()->used());
92 Threads::gc_epilogue();
93 CodeCache::gc_epilogue();
95 // refs processing: clean slate
96 GenMarkSweep::_ref_processor = NULL;
97 }
100 void G1MarkSweep::allocate_stacks() {
101 GenMarkSweep::_preserved_count_max = 0;
102 GenMarkSweep::_preserved_marks = NULL;
103 GenMarkSweep::_preserved_count = 0;
104 GenMarkSweep::_preserved_mark_stack = NULL;
105 GenMarkSweep::_preserved_oop_stack = NULL;
107 GenMarkSweep::_marking_stack =
108 new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true);
109 GenMarkSweep::_objarray_stack =
110 new (ResourceObj::C_HEAP) GrowableArray<ObjArrayTask>(50, true);
112 int size = SystemDictionary::number_of_classes() * 2;
113 GenMarkSweep::_revisit_klass_stack =
114 new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true);
115 // (#klass/k)^2 for k ~ 10 appears a better fit, but this will have to do
116 // for now until we have a chance to work out a more optimal setting.
117 GenMarkSweep::_revisit_mdo_stack =
118 new (ResourceObj::C_HEAP) GrowableArray<DataLayout*>(size*2, true);
120 }
122 void G1MarkSweep::mark_sweep_phase1(bool& marked_for_unloading,
123 bool clear_all_softrefs) {
124 // Recursively traverse all live objects and mark them
125 EventMark m("1 mark object");
126 TraceTime tm("phase 1", PrintGC && Verbose, true, gclog_or_tty);
127 GenMarkSweep::trace(" 1");
129 SharedHeap* sh = SharedHeap::heap();
131 sh->process_strong_roots(true, // activeate StrongRootsScope
132 true, // Collecting permanent generation.
133 SharedHeap::SO_SystemClasses,
134 &GenMarkSweep::follow_root_closure,
135 &GenMarkSweep::follow_code_root_closure,
136 &GenMarkSweep::follow_root_closure);
138 // Process reference objects found during marking
139 ReferenceProcessor* rp = GenMarkSweep::ref_processor();
140 rp->setup_policy(clear_all_softrefs);
141 rp->process_discovered_references(&GenMarkSweep::is_alive,
142 &GenMarkSweep::keep_alive,
143 &GenMarkSweep::follow_stack_closure,
144 NULL);
146 // Follow system dictionary roots and unload classes
147 bool purged_class = SystemDictionary::do_unloading(&GenMarkSweep::is_alive);
148 assert(GenMarkSweep::_marking_stack->is_empty(),
149 "stack should be empty by now");
151 // Follow code cache roots (has to be done after system dictionary,
152 // assumes all live klasses are marked)
153 CodeCache::do_unloading(&GenMarkSweep::is_alive,
154 &GenMarkSweep::keep_alive,
155 purged_class);
156 GenMarkSweep::follow_stack();
158 // Update subklass/sibling/implementor links of live klasses
159 GenMarkSweep::follow_weak_klass_links();
160 assert(GenMarkSweep::_marking_stack->is_empty(),
161 "stack should be empty by now");
163 // Visit memoized MDO's and clear any unmarked weak refs
164 GenMarkSweep::follow_mdo_weak_refs();
165 assert(GenMarkSweep::_marking_stack->is_empty(), "just drained");
168 // Visit symbol and interned string tables and delete unmarked oops
169 SymbolTable::unlink(&GenMarkSweep::is_alive);
170 StringTable::unlink(&GenMarkSweep::is_alive);
172 assert(GenMarkSweep::_marking_stack->is_empty(),
173 "stack should be empty by now");
174 }
176 class G1PrepareCompactClosure: public HeapRegionClosure {
177 ModRefBarrierSet* _mrbs;
178 CompactPoint _cp;
180 void free_humongous_region(HeapRegion* hr) {
181 HeapWord* bot = hr->bottom();
182 HeapWord* end = hr->end();
183 assert(hr->startsHumongous(),
184 "Only the start of a humongous region should be freed.");
185 G1CollectedHeap::heap()->free_region(hr);
186 hr->prepare_for_compaction(&_cp);
187 // Also clear the part of the card table that will be unused after
188 // compaction.
189 _mrbs->clear(MemRegion(hr->compaction_top(), hr->end()));
190 }
192 public:
193 G1PrepareCompactClosure(CompactibleSpace* cs) :
194 _cp(NULL, cs, cs->initialize_threshold()),
195 _mrbs(G1CollectedHeap::heap()->mr_bs())
196 {}
197 bool doHeapRegion(HeapRegion* hr) {
198 if (hr->isHumongous()) {
199 if (hr->startsHumongous()) {
200 oop obj = oop(hr->bottom());
201 if (obj->is_gc_marked()) {
202 obj->forward_to(obj);
203 } else {
204 free_humongous_region(hr);
205 }
206 } else {
207 assert(hr->continuesHumongous(), "Invalid humongous.");
208 }
209 } else {
210 hr->prepare_for_compaction(&_cp);
211 // Also clear the part of the card table that will be unused after
212 // compaction.
213 _mrbs->clear(MemRegion(hr->compaction_top(), hr->end()));
214 }
215 return false;
216 }
217 };
219 // Finds the first HeapRegion.
220 class FindFirstRegionClosure: public HeapRegionClosure {
221 HeapRegion* _a_region;
222 public:
223 FindFirstRegionClosure() : _a_region(NULL) {}
224 bool doHeapRegion(HeapRegion* r) {
225 _a_region = r;
226 return true;
227 }
228 HeapRegion* result() { return _a_region; }
229 };
231 void G1MarkSweep::mark_sweep_phase2() {
232 // Now all live objects are marked, compute the new object addresses.
234 // It is imperative that we traverse perm_gen LAST. If dead space is
235 // allowed a range of dead object may get overwritten by a dead int
236 // array. If perm_gen is not traversed last a klassOop may get
237 // overwritten. This is fine since it is dead, but if the class has dead
238 // instances we have to skip them, and in order to find their size we
239 // need the klassOop!
240 //
241 // It is not required that we traverse spaces in the same order in
242 // phase2, phase3 and phase4, but the ValidateMarkSweep live oops
243 // tracking expects us to do so. See comment under phase4.
245 G1CollectedHeap* g1h = G1CollectedHeap::heap();
246 Generation* pg = g1h->perm_gen();
248 EventMark m("2 compute new addresses");
249 TraceTime tm("phase 2", PrintGC && Verbose, true, gclog_or_tty);
250 GenMarkSweep::trace("2");
252 FindFirstRegionClosure cl;
253 g1h->heap_region_iterate(&cl);
254 HeapRegion *r = cl.result();
255 CompactibleSpace* sp = r;
256 if (r->isHumongous() && oop(r->bottom())->is_gc_marked()) {
257 sp = r->next_compaction_space();
258 }
260 G1PrepareCompactClosure blk(sp);
261 g1h->heap_region_iterate(&blk);
263 CompactPoint perm_cp(pg, NULL, NULL);
264 pg->prepare_for_compaction(&perm_cp);
265 }
267 class G1AdjustPointersClosure: public HeapRegionClosure {
268 public:
269 bool doHeapRegion(HeapRegion* r) {
270 if (r->isHumongous()) {
271 if (r->startsHumongous()) {
272 // We must adjust the pointers on the single H object.
273 oop obj = oop(r->bottom());
274 debug_only(GenMarkSweep::track_interior_pointers(obj));
275 // point all the oops to the new location
276 obj->adjust_pointers();
277 debug_only(GenMarkSweep::check_interior_pointers());
278 }
279 } else {
280 // This really ought to be "as_CompactibleSpace"...
281 r->adjust_pointers();
282 }
283 return false;
284 }
285 };
287 void G1MarkSweep::mark_sweep_phase3() {
288 G1CollectedHeap* g1h = G1CollectedHeap::heap();
289 Generation* pg = g1h->perm_gen();
291 // Adjust the pointers to reflect the new locations
292 EventMark m("3 adjust pointers");
293 TraceTime tm("phase 3", PrintGC && Verbose, true, gclog_or_tty);
294 GenMarkSweep::trace("3");
296 SharedHeap* sh = SharedHeap::heap();
298 sh->process_strong_roots(true, // activate StrongRootsScope
299 true, // Collecting permanent generation.
300 SharedHeap::SO_AllClasses,
301 &GenMarkSweep::adjust_root_pointer_closure,
302 NULL, // do not touch code cache here
303 &GenMarkSweep::adjust_pointer_closure);
305 g1h->ref_processor()->weak_oops_do(&GenMarkSweep::adjust_root_pointer_closure);
307 // Now adjust pointers in remaining weak roots. (All of which should
308 // have been cleared if they pointed to non-surviving objects.)
309 g1h->g1_process_weak_roots(&GenMarkSweep::adjust_root_pointer_closure,
310 &GenMarkSweep::adjust_pointer_closure);
312 GenMarkSweep::adjust_marks();
314 G1AdjustPointersClosure blk;
315 g1h->heap_region_iterate(&blk);
316 pg->adjust_pointers();
317 }
319 class G1SpaceCompactClosure: public HeapRegionClosure {
320 public:
321 G1SpaceCompactClosure() {}
323 bool doHeapRegion(HeapRegion* hr) {
324 if (hr->isHumongous()) {
325 if (hr->startsHumongous()) {
326 oop obj = oop(hr->bottom());
327 if (obj->is_gc_marked()) {
328 obj->init_mark();
329 } else {
330 assert(hr->is_empty(), "Should have been cleared in phase 2.");
331 }
332 hr->reset_during_compaction();
333 }
334 } else {
335 hr->compact();
336 }
337 return false;
338 }
339 };
341 void G1MarkSweep::mark_sweep_phase4() {
342 // All pointers are now adjusted, move objects accordingly
344 // It is imperative that we traverse perm_gen first in phase4. All
345 // classes must be allocated earlier than their instances, and traversing
346 // perm_gen first makes sure that all klassOops have moved to their new
347 // location before any instance does a dispatch through it's klass!
349 // The ValidateMarkSweep live oops tracking expects us to traverse spaces
350 // in the same order in phase2, phase3 and phase4. We don't quite do that
351 // here (perm_gen first rather than last), so we tell the validate code
352 // to use a higher index (saved from phase2) when verifying perm_gen.
353 G1CollectedHeap* g1h = G1CollectedHeap::heap();
354 Generation* pg = g1h->perm_gen();
356 EventMark m("4 compact heap");
357 TraceTime tm("phase 4", PrintGC && Verbose, true, gclog_or_tty);
358 GenMarkSweep::trace("4");
360 pg->compact();
362 G1SpaceCompactClosure blk;
363 g1h->heap_region_iterate(&blk);
365 }
367 // Local Variables: ***
368 // c-indentation-style: gnu ***
369 // End: ***