Wed, 02 Jul 2008 12:55:16 -0700
6719955: Update copyright year
Summary: Update copyright year for files that have been modified in 2008
Reviewed-by: ohair, tbell
1 /*
2 * Copyright 2001-2008 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 */
25 class ChunkArray;
26 class ParScanWithoutBarrierClosure;
27 class ParScanWithBarrierClosure;
28 class ParRootScanWithoutBarrierClosure;
29 class ParRootScanWithBarrierTwoGensClosure;
30 class ParEvacuateFollowersClosure;
32 // It would be better if these types could be kept local to the .cpp file,
33 // but they must be here to allow ParScanClosure::do_oop_work to be defined
34 // in genOopClosures.inline.hpp.
36 typedef OopTaskQueue ObjToScanQueue;
37 typedef OopTaskQueueSet ObjToScanQueueSet;
39 // Enable this to get push/pop/steal stats.
40 const int PAR_STATS_ENABLED = 0;
42 class ParKeepAliveClosure: public DefNewGeneration::KeepAliveClosure {
43 private:
44 ParScanWeakRefClosure* _par_cl;
45 protected:
46 template <class T> void do_oop_work(T* p);
47 public:
48 ParKeepAliveClosure(ParScanWeakRefClosure* cl);
49 virtual void do_oop(oop* p);
50 virtual void do_oop(narrowOop* p);
51 };
53 // The state needed by thread performing parallel young-gen collection.
54 class ParScanThreadState {
55 friend class ParScanThreadStateSet;
56 private:
57 ObjToScanQueue *_work_queue;
59 ParGCAllocBuffer _to_space_alloc_buffer;
61 ParScanWithoutBarrierClosure _to_space_closure; // scan_without_gc_barrier
62 ParScanWithBarrierClosure _old_gen_closure; // scan_with_gc_barrier
63 ParRootScanWithoutBarrierClosure _to_space_root_closure; // scan_root_without_gc_barrier
64 // One of these two will be passed to process_strong_roots, which will
65 // set its generation. The first is for two-gen configs where the
66 // old gen collects the perm gen; the second is for arbitrary configs.
67 // The second isn't used right now (it used to be used for the train, an
68 // incremental collector) but the declaration has been left as a reminder.
69 ParRootScanWithBarrierTwoGensClosure _older_gen_closure;
70 // This closure will always be bound to the old gen; it will be used
71 // in evacuate_followers.
72 ParRootScanWithBarrierTwoGensClosure _old_gen_root_closure; // scan_old_root_with_gc_barrier
73 ParEvacuateFollowersClosure _evacuate_followers;
74 DefNewGeneration::IsAliveClosure _is_alive_closure;
75 ParScanWeakRefClosure _scan_weak_ref_closure;
76 ParKeepAliveClosure _keep_alive_closure;
79 Space* _to_space;
80 Space* to_space() { return _to_space; }
82 Generation* _old_gen;
83 Generation* old_gen() { return _old_gen; }
85 HeapWord *_young_old_boundary;
87 int _hash_seed;
88 int _thread_num;
89 ageTable _ageTable;
91 bool _to_space_full;
93 int _pushes, _pops, _steals, _steal_attempts, _term_attempts;
94 int _overflow_pushes, _overflow_refills, _overflow_refill_objs;
96 // Timing numbers.
97 double _start;
98 double _start_strong_roots;
99 double _strong_roots_time;
100 double _start_term;
101 double _term_time;
103 // Helper for trim_queues. Scans subset of an array and makes
104 // remainder available for work stealing.
105 void scan_partial_array_and_push_remainder(oop obj);
107 // In support of CMS' parallel rescan of survivor space.
108 ChunkArray* _survivor_chunk_array;
109 ChunkArray* survivor_chunk_array() { return _survivor_chunk_array; }
111 void record_survivor_plab(HeapWord* plab_start, size_t plab_word_size);
113 ParScanThreadState(Space* to_space_, ParNewGeneration* gen_,
114 Generation* old_gen_, int thread_num_,
115 ObjToScanQueueSet* work_queue_set_, size_t desired_plab_sz_,
116 ParallelTaskTerminator& term_);
118 public:
119 ageTable* age_table() {return &_ageTable;}
121 ObjToScanQueue* work_queue() { return _work_queue; }
123 ParGCAllocBuffer* to_space_alloc_buffer() {
124 return &_to_space_alloc_buffer;
125 }
127 ParEvacuateFollowersClosure& evacuate_followers_closure() { return _evacuate_followers; }
128 DefNewGeneration::IsAliveClosure& is_alive_closure() { return _is_alive_closure; }
129 ParScanWeakRefClosure& scan_weak_ref_closure() { return _scan_weak_ref_closure; }
130 ParKeepAliveClosure& keep_alive_closure() { return _keep_alive_closure; }
131 ParScanClosure& older_gen_closure() { return _older_gen_closure; }
132 ParRootScanWithoutBarrierClosure& to_space_root_closure() { return _to_space_root_closure; };
134 // Decrease queue size below "max_size".
135 void trim_queues(int max_size);
137 // Is new_obj a candidate for scan_partial_array_and_push_remainder method.
138 inline bool should_be_partially_scanned(oop new_obj, oop old_obj) const;
140 int* hash_seed() { return &_hash_seed; }
141 int thread_num() { return _thread_num; }
143 // Allocate a to-space block of size "sz", or else return NULL.
144 HeapWord* alloc_in_to_space_slow(size_t word_sz);
146 HeapWord* alloc_in_to_space(size_t word_sz) {
147 HeapWord* obj = to_space_alloc_buffer()->allocate(word_sz);
148 if (obj != NULL) return obj;
149 else return alloc_in_to_space_slow(word_sz);
150 }
152 HeapWord* young_old_boundary() { return _young_old_boundary; }
154 void set_young_old_boundary(HeapWord *boundary) {
155 _young_old_boundary = boundary;
156 }
158 // Undo the most recent allocation ("obj", of "word_sz").
159 void undo_alloc_in_to_space(HeapWord* obj, size_t word_sz);
161 int pushes() { return _pushes; }
162 int pops() { return _pops; }
163 int steals() { return _steals; }
164 int steal_attempts() { return _steal_attempts; }
165 int term_attempts() { return _term_attempts; }
166 int overflow_pushes() { return _overflow_pushes; }
167 int overflow_refills() { return _overflow_refills; }
168 int overflow_refill_objs() { return _overflow_refill_objs; }
170 void note_push() { if (PAR_STATS_ENABLED) _pushes++; }
171 void note_pop() { if (PAR_STATS_ENABLED) _pops++; }
172 void note_steal() { if (PAR_STATS_ENABLED) _steals++; }
173 void note_steal_attempt() { if (PAR_STATS_ENABLED) _steal_attempts++; }
174 void note_term_attempt() { if (PAR_STATS_ENABLED) _term_attempts++; }
175 void note_overflow_push() { if (PAR_STATS_ENABLED) _overflow_pushes++; }
176 void note_overflow_refill(int objs) {
177 if (PAR_STATS_ENABLED) {
178 _overflow_refills++;
179 _overflow_refill_objs += objs;
180 }
181 }
183 void start_strong_roots() {
184 _start_strong_roots = os::elapsedTime();
185 }
186 void end_strong_roots() {
187 _strong_roots_time += (os::elapsedTime() - _start_strong_roots);
188 }
189 double strong_roots_time() { return _strong_roots_time; }
190 void start_term_time() {
191 note_term_attempt();
192 _start_term = os::elapsedTime();
193 }
194 void end_term_time() {
195 _term_time += (os::elapsedTime() - _start_term);
196 }
197 double term_time() { return _term_time; }
199 double elapsed() {
200 return os::elapsedTime() - _start;
201 }
202 };
204 class ParNewGenTask: public AbstractGangTask {
205 private:
206 ParNewGeneration* _gen;
207 Generation* _next_gen;
208 HeapWord* _young_old_boundary;
209 class ParScanThreadStateSet* _state_set;
211 public:
212 ParNewGenTask(ParNewGeneration* gen,
213 Generation* next_gen,
214 HeapWord* young_old_boundary,
215 ParScanThreadStateSet* state_set);
217 HeapWord* young_old_boundary() { return _young_old_boundary; }
219 void work(int i);
220 };
222 class KeepAliveClosure: public DefNewGeneration::KeepAliveClosure {
223 protected:
224 template <class T> void do_oop_work(T* p);
225 public:
226 KeepAliveClosure(ScanWeakRefClosure* cl);
227 virtual void do_oop(oop* p);
228 virtual void do_oop(narrowOop* p);
229 };
231 class EvacuateFollowersClosureGeneral: public VoidClosure {
232 private:
233 GenCollectedHeap* _gch;
234 int _level;
235 OopsInGenClosure* _scan_cur_or_nonheap;
236 OopsInGenClosure* _scan_older;
237 public:
238 EvacuateFollowersClosureGeneral(GenCollectedHeap* gch, int level,
239 OopsInGenClosure* cur,
240 OopsInGenClosure* older);
241 virtual void do_void();
242 };
244 // Closure for scanning ParNewGeneration.
245 // Same as ScanClosure, except does parallel GC barrier.
246 class ScanClosureWithParBarrier: public ScanClosure {
247 protected:
248 template <class T> void do_oop_work(T* p);
249 public:
250 ScanClosureWithParBarrier(ParNewGeneration* g, bool gc_barrier);
251 virtual void do_oop(oop* p);
252 virtual void do_oop(narrowOop* p);
253 };
255 // Implements AbstractRefProcTaskExecutor for ParNew.
256 class ParNewRefProcTaskExecutor: public AbstractRefProcTaskExecutor {
257 private:
258 ParNewGeneration& _generation;
259 ParScanThreadStateSet& _state_set;
260 public:
261 ParNewRefProcTaskExecutor(ParNewGeneration& generation,
262 ParScanThreadStateSet& state_set)
263 : _generation(generation), _state_set(state_set)
264 { }
266 // Executes a task using worker threads.
267 virtual void execute(ProcessTask& task);
268 virtual void execute(EnqueueTask& task);
269 // Switch to single threaded mode.
270 virtual void set_single_threaded_mode();
271 };
274 // A Generation that does parallel young-gen collection.
276 class ParNewGeneration: public DefNewGeneration {
277 friend class ParNewGenTask;
278 friend class ParNewRefProcTask;
279 friend class ParNewRefProcTaskExecutor;
280 friend class ParScanThreadStateSet;
282 private:
283 // XXX use a global constant instead of 64!
284 struct ObjToScanQueuePadded {
285 ObjToScanQueue work_queue;
286 char pad[64 - sizeof(ObjToScanQueue)]; // prevent false sharing
287 };
289 // The per-thread work queues, available here for stealing.
290 ObjToScanQueueSet* _task_queues;
292 // Desired size of survivor space plab's
293 PLABStats _plab_stats;
295 // A list of from-space images of to-be-scanned objects, threaded through
296 // klass-pointers (klass information already copied to the forwarded
297 // image.) Manipulated with CAS.
298 oop _overflow_list;
300 // If true, older generation does not support promotion undo, so avoid.
301 static bool _avoid_promotion_undo;
303 // This closure is used by the reference processor to filter out
304 // references to live referent.
305 DefNewGeneration::IsAliveClosure _is_alive_closure;
307 static oop real_forwardee_slow(oop obj);
308 static void waste_some_time();
310 // Preserve the mark of "obj", if necessary, in preparation for its mark
311 // word being overwritten with a self-forwarding-pointer.
312 void preserve_mark_if_necessary(oop obj, markOop m);
314 protected:
316 bool _survivor_overflow;
318 bool avoid_promotion_undo() { return _avoid_promotion_undo; }
319 void set_avoid_promotion_undo(bool v) { _avoid_promotion_undo = v; }
321 bool survivor_overflow() { return _survivor_overflow; }
322 void set_survivor_overflow(bool v) { _survivor_overflow = v; }
324 // Adjust the tenuring threshold. See the implementation for
325 // the details of the policy.
326 virtual void adjust_desired_tenuring_threshold();
328 public:
329 ParNewGeneration(ReservedSpace rs, size_t initial_byte_size, int level);
331 ~ParNewGeneration() {
332 for (uint i = 0; i < ParallelGCThreads; i++)
333 delete _task_queues->queue(i);
335 delete _task_queues;
336 }
338 virtual void ref_processor_init();
339 virtual Generation::Name kind() { return Generation::ParNew; }
340 virtual const char* name() const;
341 virtual const char* short_name() const { return "ParNew"; }
343 // override
344 virtual bool refs_discovery_is_mt() const {
345 assert(UseParNewGC, "ParNewGeneration only when UseParNewGC");
346 return ParallelGCThreads > 1;
347 }
349 // Make the collection virtual.
350 virtual void collect(bool full,
351 bool clear_all_soft_refs,
352 size_t size,
353 bool is_tlab);
355 // This needs to be visible to the closure function.
356 // "obj" is the object to be copied, "m" is a recent value of its mark
357 // that must not contain a forwarding pointer (though one might be
358 // inserted in "obj"s mark word by a parallel thread).
359 inline oop copy_to_survivor_space(ParScanThreadState* par_scan_state,
360 oop obj, size_t obj_sz, markOop m) {
361 if (_avoid_promotion_undo) {
362 return copy_to_survivor_space_avoiding_promotion_undo(par_scan_state,
363 obj, obj_sz, m);
364 }
366 return copy_to_survivor_space_with_undo(par_scan_state, obj, obj_sz, m);
367 }
369 oop copy_to_survivor_space_avoiding_promotion_undo(ParScanThreadState* par_scan_state,
370 oop obj, size_t obj_sz, markOop m);
372 oop copy_to_survivor_space_with_undo(ParScanThreadState* par_scan_state,
373 oop obj, size_t obj_sz, markOop m);
375 // Push the given (from-space) object on the global overflow list.
376 void push_on_overflow_list(oop from_space_obj);
378 // If the global overflow list is non-empty, move some tasks from it
379 // onto "work_q" (which must be empty). No more than 1/4 of the
380 // max_elems of "work_q" are moved.
381 bool take_from_overflow_list(ParScanThreadState* par_scan_state);
383 // The task queues to be used by parallel GC threads.
384 ObjToScanQueueSet* task_queues() {
385 return _task_queues;
386 }
388 PLABStats* plab_stats() {
389 return &_plab_stats;
390 }
392 size_t desired_plab_sz() {
393 return _plab_stats.desired_plab_sz();
394 }
396 static oop real_forwardee(oop obj);
398 DEBUG_ONLY(static bool is_legal_forward_ptr(oop p);)
399 };