Mercurial > hg > truffle
annotate src/share/vm/memory/generation.hpp @ 21187:f74b9f898cf2
NodeLIRBuilder: move creation of jump from moveToPhi() to visitEndNode().
author | Josef Eisl <josef.eisl@jku.at> |
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date | Mon, 20 Apr 2015 11:56:21 +0200 |
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0 | 1 /* |
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2 * Copyright (c) 1997, 2014, Oracle and/or its affiliates. All rights reserved. |
0 | 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. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #ifndef SHARE_VM_MEMORY_GENERATION_HPP |
26 #define SHARE_VM_MEMORY_GENERATION_HPP | |
27 | |
28 #include "gc_implementation/shared/collectorCounters.hpp" | |
29 #include "memory/allocation.hpp" | |
30 #include "memory/memRegion.hpp" | |
31 #include "memory/referenceProcessor.hpp" | |
32 #include "memory/universe.hpp" | |
33 #include "memory/watermark.hpp" | |
34 #include "runtime/mutex.hpp" | |
35 #include "runtime/perfData.hpp" | |
36 #include "runtime/virtualspace.hpp" | |
37 | |
0 | 38 // A Generation models a heap area for similarly-aged objects. |
39 // It will contain one ore more spaces holding the actual objects. | |
40 // | |
41 // The Generation class hierarchy: | |
42 // | |
43 // Generation - abstract base class | |
44 // - DefNewGeneration - allocation area (copy collected) | |
45 // - ParNewGeneration - a DefNewGeneration that is collected by | |
46 // several threads | |
47 // - CardGeneration - abstract class adding offset array behavior | |
48 // - OneContigSpaceCardGeneration - abstract class holding a single | |
49 // contiguous space with card marking | |
50 // - TenuredGeneration - tenured (old object) space (markSweepCompact) | |
51 // - ConcurrentMarkSweepGeneration - Mostly Concurrent Mark Sweep Generation | |
52 // (Detlefs-Printezis refinement of | |
53 // Boehm-Demers-Schenker) | |
54 // | |
55 // The system configurations currently allowed are: | |
56 // | |
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57 // DefNewGeneration + TenuredGeneration |
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58 // DefNewGeneration + ConcurrentMarkSweepGeneration |
0 | 59 // |
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60 // ParNewGeneration + TenuredGeneration |
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61 // ParNewGeneration + ConcurrentMarkSweepGeneration |
0 | 62 // |
63 | |
64 class DefNewGeneration; | |
65 class GenerationSpec; | |
66 class CompactibleSpace; | |
67 class ContiguousSpace; | |
68 class CompactPoint; | |
69 class OopsInGenClosure; | |
70 class OopClosure; | |
71 class ScanClosure; | |
72 class FastScanClosure; | |
73 class GenCollectedHeap; | |
74 class GenRemSet; | |
75 class GCStats; | |
76 | |
77 // A "ScratchBlock" represents a block of memory in one generation usable by | |
78 // another. It represents "num_words" free words, starting at and including | |
79 // the address of "this". | |
80 struct ScratchBlock { | |
81 ScratchBlock* next; | |
82 size_t num_words; | |
83 HeapWord scratch_space[1]; // Actually, of size "num_words-2" (assuming | |
84 // first two fields are word-sized.) | |
85 }; | |
86 | |
87 | |
6197 | 88 class Generation: public CHeapObj<mtGC> { |
0 | 89 friend class VMStructs; |
90 private: | |
91 jlong _time_of_last_gc; // time when last gc on this generation happened (ms) | |
92 MemRegion _prev_used_region; // for collectors that want to "remember" a value for | |
93 // used region at some specific point during collection. | |
94 | |
95 protected: | |
96 // Minimum and maximum addresses for memory reserved (not necessarily | |
97 // committed) for generation. | |
98 // Used by card marking code. Must not overlap with address ranges of | |
99 // other generations. | |
100 MemRegion _reserved; | |
101 | |
102 // Memory area reserved for generation | |
103 VirtualSpace _virtual_space; | |
104 | |
105 // Level in the generation hierarchy. | |
106 int _level; | |
107 | |
108 // ("Weak") Reference processing support | |
109 ReferenceProcessor* _ref_processor; | |
110 | |
111 // Performance Counters | |
112 CollectorCounters* _gc_counters; | |
113 | |
114 // Statistics for garbage collection | |
115 GCStats* _gc_stats; | |
116 | |
117 // Returns the next generation in the configuration, or else NULL if this | |
118 // is the highest generation. | |
119 Generation* next_gen() const; | |
120 | |
121 // Initialize the generation. | |
122 Generation(ReservedSpace rs, size_t initial_byte_size, int level); | |
123 | |
124 // Apply "cl->do_oop" to (the address of) (exactly) all the ref fields in | |
125 // "sp" that point into younger generations. | |
126 // The iteration is only over objects allocated at the start of the | |
127 // iterations; objects allocated as a result of applying the closure are | |
128 // not included. | |
129 void younger_refs_in_space_iterate(Space* sp, OopsInGenClosure* cl); | |
130 | |
131 public: | |
132 // The set of possible generation kinds. | |
133 enum Name { | |
134 ASParNew, | |
135 ASConcurrentMarkSweep, | |
136 DefNew, | |
137 ParNew, | |
138 MarkSweepCompact, | |
139 ConcurrentMarkSweep, | |
140 Other | |
141 }; | |
142 | |
143 enum SomePublicConstants { | |
144 // Generations are GenGrain-aligned and have size that are multiples of | |
145 // GenGrain. | |
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146 // Note: on ARM we add 1 bit for card_table_base to be properly aligned |
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147 // (we expect its low byte to be zero - see implementation of post_barrier) |
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148 LogOfGenGrain = 16 ARM_ONLY(+1), |
0 | 149 GenGrain = 1 << LogOfGenGrain |
150 }; | |
151 | |
152 // allocate and initialize ("weak") refs processing support | |
153 virtual void ref_processor_init(); | |
154 void set_ref_processor(ReferenceProcessor* rp) { | |
155 assert(_ref_processor == NULL, "clobbering existing _ref_processor"); | |
156 _ref_processor = rp; | |
157 } | |
158 | |
159 virtual Generation::Name kind() { return Generation::Other; } | |
160 GenerationSpec* spec(); | |
161 | |
162 // This properly belongs in the collector, but for now this | |
163 // will do. | |
164 virtual bool refs_discovery_is_atomic() const { return true; } | |
165 virtual bool refs_discovery_is_mt() const { return false; } | |
166 | |
167 // Space enquiries (results in bytes) | |
168 virtual size_t capacity() const = 0; // The maximum number of object bytes the | |
169 // generation can currently hold. | |
170 virtual size_t used() const = 0; // The number of used bytes in the gen. | |
171 virtual size_t free() const = 0; // The number of free bytes in the gen. | |
172 | |
173 // Support for java.lang.Runtime.maxMemory(); see CollectedHeap. | |
174 // Returns the total number of bytes available in a generation | |
175 // for the allocation of objects. | |
176 virtual size_t max_capacity() const; | |
177 | |
178 // If this is a young generation, the maximum number of bytes that can be | |
179 // allocated in this generation before a GC is triggered. | |
180 virtual size_t capacity_before_gc() const { return 0; } | |
181 | |
182 // The largest number of contiguous free bytes in the generation, | |
183 // including expansion (Assumes called at a safepoint.) | |
184 virtual size_t contiguous_available() const = 0; | |
185 // The largest number of contiguous free bytes in this or any higher generation. | |
186 virtual size_t max_contiguous_available() const; | |
187 | |
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188 // Returns true if promotions of the specified amount are |
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189 // likely to succeed without a promotion failure. |
0 | 190 // Promotion of the full amount is not guaranteed but |
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191 // might be attempted in the worst case. |
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192 virtual bool promotion_attempt_is_safe(size_t max_promotion_in_bytes) const; |
0 | 193 |
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194 // For a non-young generation, this interface can be used to inform a |
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195 // generation that a promotion attempt into that generation failed. |
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196 // Typically used to enable diagnostic output for post-mortem analysis, |
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197 // but other uses of the interface are not ruled out. |
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198 virtual void promotion_failure_occurred() { /* does nothing */ } |
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199 |
0 | 200 // Return an estimate of the maximum allocation that could be performed |
201 // in the generation without triggering any collection or expansion | |
202 // activity. It is "unsafe" because no locks are taken; the result | |
203 // should be treated as an approximation, not a guarantee, for use in | |
204 // heuristic resizing decisions. | |
205 virtual size_t unsafe_max_alloc_nogc() const = 0; | |
206 | |
207 // Returns true if this generation cannot be expanded further | |
208 // without a GC. Override as appropriate. | |
209 virtual bool is_maximal_no_gc() const { | |
210 return _virtual_space.uncommitted_size() == 0; | |
211 } | |
212 | |
213 MemRegion reserved() const { return _reserved; } | |
214 | |
215 // Returns a region guaranteed to contain all the objects in the | |
216 // generation. | |
217 virtual MemRegion used_region() const { return _reserved; } | |
218 | |
219 MemRegion prev_used_region() const { return _prev_used_region; } | |
220 virtual void save_used_region() { _prev_used_region = used_region(); } | |
221 | |
4708 | 222 // Returns "TRUE" iff "p" points into the committed areas in the generation. |
0 | 223 // For some kinds of generations, this may be an expensive operation. |
224 // To avoid performance problems stemming from its inadvertent use in | |
225 // product jvm's, we restrict its use to assertion checking or | |
226 // verification only. | |
227 virtual bool is_in(const void* p) const; | |
228 | |
229 /* Returns "TRUE" iff "p" points into the reserved area of the generation. */ | |
230 bool is_in_reserved(const void* p) const { | |
231 return _reserved.contains(p); | |
232 } | |
233 | |
234 // Check that the generation kind is DefNewGeneration or a sub | |
235 // class of DefNewGeneration and return a DefNewGeneration* | |
236 DefNewGeneration* as_DefNewGeneration(); | |
237 | |
238 // If some space in the generation contains the given "addr", return a | |
239 // pointer to that space, else return "NULL". | |
240 virtual Space* space_containing(const void* addr) const; | |
241 | |
242 // Iteration - do not use for time critical operations | |
243 virtual void space_iterate(SpaceClosure* blk, bool usedOnly = false) = 0; | |
244 | |
245 // Returns the first space, if any, in the generation that can participate | |
246 // in compaction, or else "NULL". | |
247 virtual CompactibleSpace* first_compaction_space() const = 0; | |
248 | |
249 // Returns "true" iff this generation should be used to allocate an | |
250 // object of the given size. Young generations might | |
251 // wish to exclude very large objects, for example, since, if allocated | |
252 // often, they would greatly increase the frequency of young-gen | |
253 // collection. | |
254 virtual bool should_allocate(size_t word_size, bool is_tlab) { | |
255 bool result = false; | |
256 size_t overflow_limit = (size_t)1 << (BitsPerSize_t - LogHeapWordSize); | |
257 if (!is_tlab || supports_tlab_allocation()) { | |
258 result = (word_size > 0) && (word_size < overflow_limit); | |
259 } | |
260 return result; | |
261 } | |
262 | |
263 // Allocate and returns a block of the requested size, or returns "NULL". | |
264 // Assumes the caller has done any necessary locking. | |
265 virtual HeapWord* allocate(size_t word_size, bool is_tlab) = 0; | |
266 | |
267 // Like "allocate", but performs any necessary locking internally. | |
268 virtual HeapWord* par_allocate(size_t word_size, bool is_tlab) = 0; | |
269 | |
270 // A 'younger' gen has reached an allocation limit, and uses this to notify | |
271 // the next older gen. The return value is a new limit, or NULL if none. The | |
272 // caller must do the necessary locking. | |
273 virtual HeapWord* allocation_limit_reached(Space* space, HeapWord* top, | |
274 size_t word_size) { | |
275 return NULL; | |
276 } | |
277 | |
278 // Some generation may offer a region for shared, contiguous allocation, | |
279 // via inlined code (by exporting the address of the top and end fields | |
280 // defining the extent of the contiguous allocation region.) | |
281 | |
282 // This function returns "true" iff the heap supports this kind of | |
283 // allocation. (More precisely, this means the style of allocation that | |
284 // increments *top_addr()" with a CAS.) (Default is "no".) | |
285 // A generation that supports this allocation style must use lock-free | |
286 // allocation for *all* allocation, since there are times when lock free | |
287 // allocation will be concurrent with plain "allocate" calls. | |
288 virtual bool supports_inline_contig_alloc() const { return false; } | |
289 | |
290 // These functions return the addresses of the fields that define the | |
291 // boundaries of the contiguous allocation area. (These fields should be | |
292 // physicall near to one another.) | |
293 virtual HeapWord** top_addr() const { return NULL; } | |
294 virtual HeapWord** end_addr() const { return NULL; } | |
295 | |
296 // Thread-local allocation buffers | |
297 virtual bool supports_tlab_allocation() const { return false; } | |
298 virtual size_t tlab_capacity() const { | |
299 guarantee(false, "Generation doesn't support thread local allocation buffers"); | |
300 return 0; | |
301 } | |
17727 | 302 virtual size_t tlab_used() const { |
303 guarantee(false, "Generation doesn't support thread local allocation buffers"); | |
304 return 0; | |
305 } | |
0 | 306 virtual size_t unsafe_max_tlab_alloc() const { |
307 guarantee(false, "Generation doesn't support thread local allocation buffers"); | |
308 return 0; | |
309 } | |
310 | |
311 // "obj" is the address of an object in a younger generation. Allocate space | |
312 // for "obj" in the current (or some higher) generation, and copy "obj" into | |
313 // the newly allocated space, if possible, returning the result (or NULL if | |
314 // the allocation failed). | |
315 // | |
316 // The "obj_size" argument is just obj->size(), passed along so the caller can | |
317 // avoid repeating the virtual call to retrieve it. | |
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318 virtual oop promote(oop obj, size_t obj_size); |
0 | 319 |
320 // Thread "thread_num" (0 <= i < ParalleGCThreads) wants to promote | |
321 // object "obj", whose original mark word was "m", and whose size is | |
322 // "word_sz". If possible, allocate space for "obj", copy obj into it | |
323 // (taking care to copy "m" into the mark word when done, since the mark | |
324 // word of "obj" may have been overwritten with a forwarding pointer, and | |
325 // also taking care to copy the klass pointer *last*. Returns the new | |
326 // object if successful, or else NULL. | |
327 virtual oop par_promote(int thread_num, | |
328 oop obj, markOop m, size_t word_sz); | |
329 | |
330 // Undo, if possible, the most recent par_promote_alloc allocation by | |
331 // "thread_num" ("obj", of "word_sz"). | |
332 virtual void par_promote_alloc_undo(int thread_num, | |
333 HeapWord* obj, size_t word_sz); | |
334 | |
335 // Informs the current generation that all par_promote_alloc's in the | |
336 // collection have been completed; any supporting data structures can be | |
337 // reset. Default is to do nothing. | |
338 virtual void par_promote_alloc_done(int thread_num) {} | |
339 | |
340 // Informs the current generation that all oop_since_save_marks_iterates | |
341 // performed by "thread_num" in the current collection, if any, have been | |
342 // completed; any supporting data structures can be reset. Default is to | |
343 // do nothing. | |
344 virtual void par_oop_since_save_marks_iterate_done(int thread_num) {} | |
345 | |
346 // This generation will collect all younger generations | |
347 // during a full collection. | |
348 virtual bool full_collects_younger_generations() const { return false; } | |
349 | |
350 // This generation does in-place marking, meaning that mark words | |
351 // are mutated during the marking phase and presumably reinitialized | |
352 // to a canonical value after the GC. This is currently used by the | |
353 // biased locking implementation to determine whether additional | |
354 // work is required during the GC prologue and epilogue. | |
355 virtual bool performs_in_place_marking() const { return true; } | |
356 | |
357 // Returns "true" iff collect() should subsequently be called on this | |
358 // this generation. See comment below. | |
359 // This is a generic implementation which can be overridden. | |
360 // | |
361 // Note: in the current (1.4) implementation, when genCollectedHeap's | |
362 // incremental_collection_will_fail flag is set, all allocations are | |
363 // slow path (the only fast-path place to allocate is DefNew, which | |
364 // will be full if the flag is set). | |
365 // Thus, older generations which collect younger generations should | |
366 // test this flag and collect if it is set. | |
367 virtual bool should_collect(bool full, | |
368 size_t word_size, | |
369 bool is_tlab) { | |
370 return (full || should_allocate(word_size, is_tlab)); | |
371 } | |
372 | |
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373 // Returns true if the collection is likely to be safely |
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374 // completed. Even if this method returns true, a collection |
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375 // may not be guaranteed to succeed, and the system should be |
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376 // able to safely unwind and recover from that failure, albeit |
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377 // at some additional cost. |
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378 virtual bool collection_attempt_is_safe() { |
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379 guarantee(false, "Are you sure you want to call this method?"); |
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380 return true; |
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381 } |
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382 |
0 | 383 // Perform a garbage collection. |
384 // If full is true attempt a full garbage collection of this generation. | |
385 // Otherwise, attempting to (at least) free enough space to support an | |
386 // allocation of the given "word_size". | |
387 virtual void collect(bool full, | |
388 bool clear_all_soft_refs, | |
389 size_t word_size, | |
390 bool is_tlab) = 0; | |
391 | |
392 // Perform a heap collection, attempting to create (at least) enough | |
393 // space to support an allocation of the given "word_size". If | |
394 // successful, perform the allocation and return the resulting | |
395 // "oop" (initializing the allocated block). If the allocation is | |
396 // still unsuccessful, return "NULL". | |
397 virtual HeapWord* expand_and_allocate(size_t word_size, | |
398 bool is_tlab, | |
399 bool parallel = false) = 0; | |
400 | |
401 // Some generations may require some cleanup or preparation actions before | |
402 // allowing a collection. The default is to do nothing. | |
403 virtual void gc_prologue(bool full) {}; | |
404 | |
405 // Some generations may require some cleanup actions after a collection. | |
406 // The default is to do nothing. | |
407 virtual void gc_epilogue(bool full) {}; | |
408 | |
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409 // Save the high water marks for the used space in a generation. |
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410 virtual void record_spaces_top() {}; |
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411 |
0 | 412 // Some generations may need to be "fixed-up" after some allocation |
413 // activity to make them parsable again. The default is to do nothing. | |
414 virtual void ensure_parsability() {}; | |
415 | |
416 // Time (in ms) when we were last collected or now if a collection is | |
417 // in progress. | |
418 virtual jlong time_of_last_gc(jlong now) { | |
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419 // Both _time_of_last_gc and now are set using a time source |
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420 // that guarantees monotonically non-decreasing values provided |
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421 // the underlying platform provides such a source. So we still |
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422 // have to guard against non-monotonicity. |
0 | 423 NOT_PRODUCT( |
424 if (now < _time_of_last_gc) { | |
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425 warning("time warp: "INT64_FORMAT" to "INT64_FORMAT, (int64_t)_time_of_last_gc, (int64_t)now); |
0 | 426 } |
427 ) | |
428 return _time_of_last_gc; | |
429 } | |
430 | |
431 virtual void update_time_of_last_gc(jlong now) { | |
432 _time_of_last_gc = now; | |
433 } | |
434 | |
435 // Generations may keep statistics about collection. This | |
436 // method updates those statistics. current_level is | |
437 // the level of the collection that has most recently | |
438 // occurred. This allows the generation to decide what | |
439 // statistics are valid to collect. For example, the | |
440 // generation can decide to gather the amount of promoted data | |
441 // if the collection of the younger generations has completed. | |
442 GCStats* gc_stats() const { return _gc_stats; } | |
443 virtual void update_gc_stats(int current_level, bool full) {} | |
444 | |
445 // Mark sweep support phase2 | |
446 virtual void prepare_for_compaction(CompactPoint* cp); | |
447 // Mark sweep support phase3 | |
448 virtual void adjust_pointers(); | |
449 // Mark sweep support phase4 | |
450 virtual void compact(); | |
451 virtual void post_compact() {ShouldNotReachHere();} | |
452 | |
453 // Support for CMS's rescan. In this general form we return a pointer | |
454 // to an abstract object that can be used, based on specific previously | |
455 // decided protocols, to exchange information between generations, | |
456 // information that may be useful for speeding up certain types of | |
457 // garbage collectors. A NULL value indicates to the client that | |
458 // no data recording is expected by the provider. The data-recorder is | |
459 // expected to be GC worker thread-local, with the worker index | |
460 // indicated by "thr_num". | |
461 virtual void* get_data_recorder(int thr_num) { return NULL; } | |
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462 virtual void sample_eden_chunk() {} |
0 | 463 |
464 // Some generations may require some cleanup actions before allowing | |
465 // a verification. | |
466 virtual void prepare_for_verify() {}; | |
467 | |
468 // Accessing "marks". | |
469 | |
470 // This function gives a generation a chance to note a point between | |
471 // collections. For example, a contiguous generation might note the | |
472 // beginning allocation point post-collection, which might allow some later | |
473 // operations to be optimized. | |
474 virtual void save_marks() {} | |
475 | |
476 // This function allows generations to initialize any "saved marks". That | |
477 // is, should only be called when the generation is empty. | |
478 virtual void reset_saved_marks() {} | |
479 | |
480 // This function is "true" iff any no allocations have occurred in the | |
481 // generation since the last call to "save_marks". | |
482 virtual bool no_allocs_since_save_marks() = 0; | |
483 | |
484 // Apply "cl->apply" to (the addresses of) all reference fields in objects | |
485 // allocated in the current generation since the last call to "save_marks". | |
486 // If more objects are allocated in this generation as a result of applying | |
487 // the closure, iterates over reference fields in those objects as well. | |
488 // Calls "save_marks" at the end of the iteration. | |
489 // General signature... | |
490 virtual void oop_since_save_marks_iterate_v(OopsInGenClosure* cl) = 0; | |
491 // ...and specializations for de-virtualization. (The general | |
492 // implemention of the _nv versions call the virtual version. | |
493 // Note that the _nv suffix is not really semantically necessary, | |
494 // but it avoids some not-so-useful warnings on Solaris.) | |
495 #define Generation_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ | |
496 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \ | |
497 oop_since_save_marks_iterate_v((OopsInGenClosure*)cl); \ | |
498 } | |
499 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(Generation_SINCE_SAVE_MARKS_DECL) | |
500 | |
501 #undef Generation_SINCE_SAVE_MARKS_DECL | |
502 | |
503 // The "requestor" generation is performing some garbage collection | |
504 // action for which it would be useful to have scratch space. If | |
505 // the target is not the requestor, no gc actions will be required | |
506 // of the target. The requestor promises to allocate no more than | |
507 // "max_alloc_words" in the target generation (via promotion say, | |
508 // if the requestor is a young generation and the target is older). | |
509 // If the target generation can provide any scratch space, it adds | |
510 // it to "list", leaving "list" pointing to the head of the | |
511 // augmented list. The default is to offer no space. | |
512 virtual void contribute_scratch(ScratchBlock*& list, Generation* requestor, | |
513 size_t max_alloc_words) {} | |
514 | |
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515 // Give each generation an opportunity to do clean up for any |
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516 // contributed scratch. |
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517 virtual void reset_scratch() {}; |
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518 |
0 | 519 // When an older generation has been collected, and perhaps resized, |
520 // this method will be invoked on all younger generations (from older to | |
521 // younger), allowing them to resize themselves as appropriate. | |
522 virtual void compute_new_size() = 0; | |
523 | |
524 // Printing | |
525 virtual const char* name() const = 0; | |
526 virtual const char* short_name() const = 0; | |
527 | |
528 int level() const { return _level; } | |
529 | |
530 // Attributes | |
531 | |
532 // True iff the given generation may only be the youngest generation. | |
533 virtual bool must_be_youngest() const = 0; | |
534 // True iff the given generation may only be the oldest generation. | |
535 virtual bool must_be_oldest() const = 0; | |
536 | |
537 // Reference Processing accessor | |
538 ReferenceProcessor* const ref_processor() { return _ref_processor; } | |
539 | |
540 // Iteration. | |
541 | |
542 // Iterate over all the ref-containing fields of all objects in the | |
543 // generation, calling "cl.do_oop" on each. | |
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544 virtual void oop_iterate(ExtendedOopClosure* cl); |
0 | 545 |
546 // Iterate over all objects in the generation, calling "cl.do_object" on | |
547 // each. | |
548 virtual void object_iterate(ObjectClosure* cl); | |
549 | |
517
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550 // Iterate over all safe objects in the generation, calling "cl.do_object" on |
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551 // each. An object is safe if its references point to other objects in |
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552 // the heap. This defaults to object_iterate() unless overridden. |
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553 virtual void safe_object_iterate(ObjectClosure* cl); |
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554 |
0 | 555 // Apply "cl->do_oop" to (the address of) all and only all the ref fields |
556 // in the current generation that contain pointers to objects in younger | |
557 // generations. Objects allocated since the last "save_marks" call are | |
558 // excluded. | |
559 virtual void younger_refs_iterate(OopsInGenClosure* cl) = 0; | |
560 | |
561 // Inform a generation that it longer contains references to objects | |
562 // in any younger generation. [e.g. Because younger gens are empty, | |
563 // clear the card table.] | |
564 virtual void clear_remembered_set() { } | |
565 | |
566 // Inform a generation that some of its objects have moved. [e.g. The | |
567 // generation's spaces were compacted, invalidating the card table.] | |
568 virtual void invalidate_remembered_set() { } | |
569 | |
570 // Block abstraction. | |
571 | |
572 // Returns the address of the start of the "block" that contains the | |
573 // address "addr". We say "blocks" instead of "object" since some heaps | |
574 // may not pack objects densely; a chunk may either be an object or a | |
575 // non-object. | |
576 virtual HeapWord* block_start(const void* addr) const; | |
577 | |
578 // Requires "addr" to be the start of a chunk, and returns its size. | |
579 // "addr + size" is required to be the start of a new chunk, or the end | |
580 // of the active area of the heap. | |
581 virtual size_t block_size(const HeapWord* addr) const ; | |
582 | |
583 // Requires "addr" to be the start of a block, and returns "TRUE" iff | |
584 // the block is an object. | |
585 virtual bool block_is_obj(const HeapWord* addr) const; | |
586 | |
587 | |
588 // PrintGC, PrintGCDetails support | |
589 void print_heap_change(size_t prev_used) const; | |
590 | |
591 // PrintHeapAtGC support | |
592 virtual void print() const; | |
593 virtual void print_on(outputStream* st) const; | |
594 | |
6008 | 595 virtual void verify() = 0; |
0 | 596 |
597 struct StatRecord { | |
598 int invocations; | |
599 elapsedTimer accumulated_time; | |
600 StatRecord() : | |
601 invocations(0), | |
602 accumulated_time(elapsedTimer()) {} | |
603 }; | |
604 private: | |
605 StatRecord _stat_record; | |
606 public: | |
607 StatRecord* stat_record() { return &_stat_record; } | |
608 | |
609 virtual void print_summary_info(); | |
610 virtual void print_summary_info_on(outputStream* st); | |
611 | |
612 // Performance Counter support | |
613 virtual void update_counters() = 0; | |
614 virtual CollectorCounters* counters() { return _gc_counters; } | |
615 }; | |
616 | |
617 // Class CardGeneration is a generation that is covered by a card table, | |
618 // and uses a card-size block-offset array to implement block_start. | |
619 | |
620 // class BlockOffsetArray; | |
621 // class BlockOffsetArrayContigSpace; | |
622 class BlockOffsetSharedArray; | |
623 | |
624 class CardGeneration: public Generation { | |
625 friend class VMStructs; | |
626 protected: | |
627 // This is shared with other generations. | |
628 GenRemSet* _rs; | |
629 // This is local to this generation. | |
630 BlockOffsetSharedArray* _bts; | |
631 | |
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632 // current shrinking effect: this damps shrinking when the heap gets empty. |
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633 size_t _shrink_factor; |
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634 |
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635 size_t _min_heap_delta_bytes; // Minimum amount to expand. |
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636 |
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637 // Some statistics from before gc started. |
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638 // These are gathered in the gc_prologue (and should_collect) |
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639 // to control growing/shrinking policy in spite of promotions. |
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640 size_t _capacity_at_prologue; |
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641 size_t _used_at_prologue; |
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642 |
0 | 643 CardGeneration(ReservedSpace rs, size_t initial_byte_size, int level, |
644 GenRemSet* remset); | |
645 | |
646 public: | |
647 | |
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648 // Attempt to expand the generation by "bytes". Expand by at a |
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649 // minimum "expand_bytes". Return true if some amount (not |
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650 // necessarily the full "bytes") was done. |
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651 virtual bool expand(size_t bytes, size_t expand_bytes); |
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652 |
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653 // Shrink generation with specified size (returns false if unable to shrink) |
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654 virtual void shrink(size_t bytes) = 0; |
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655 |
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656 virtual void compute_new_size(); |
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657 |
0 | 658 virtual void clear_remembered_set(); |
659 | |
660 virtual void invalidate_remembered_set(); | |
661 | |
662 virtual void prepare_for_verify(); | |
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663 |
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664 // Grow generation with specified size (returns false if unable to grow) |
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665 virtual bool grow_by(size_t bytes) = 0; |
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666 // Grow generation to reserved size. |
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667 virtual bool grow_to_reserved() = 0; |
0 | 668 }; |
669 | |
670 // OneContigSpaceCardGeneration models a heap of old objects contained in a single | |
671 // contiguous space. | |
672 // | |
673 // Garbage collection is performed using mark-compact. | |
674 | |
675 class OneContigSpaceCardGeneration: public CardGeneration { | |
676 friend class VMStructs; | |
677 // Abstractly, this is a subtype that gets access to protected fields. | |
678 friend class VM_PopulateDumpSharedSpace; | |
679 | |
680 protected: | |
681 ContiguousSpace* _the_space; // actual space holding objects | |
682 WaterMark _last_gc; // watermark between objects allocated before | |
683 // and after last GC. | |
684 | |
685 // Grow generation with specified size (returns false if unable to grow) | |
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686 virtual bool grow_by(size_t bytes); |
0 | 687 // Grow generation to reserved size. |
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688 virtual bool grow_to_reserved(); |
0 | 689 // Shrink generation with specified size (returns false if unable to shrink) |
690 void shrink_by(size_t bytes); | |
691 | |
692 // Allocation failure | |
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693 virtual bool expand(size_t bytes, size_t expand_bytes); |
0 | 694 void shrink(size_t bytes); |
695 | |
696 // Accessing spaces | |
697 ContiguousSpace* the_space() const { return _the_space; } | |
698 | |
699 public: | |
700 OneContigSpaceCardGeneration(ReservedSpace rs, size_t initial_byte_size, | |
701 int level, GenRemSet* remset, | |
702 ContiguousSpace* space) : | |
703 CardGeneration(rs, initial_byte_size, level, remset), | |
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704 _the_space(space) |
0 | 705 {} |
706 | |
707 inline bool is_in(const void* p) const; | |
708 | |
709 // Space enquiries | |
710 size_t capacity() const; | |
711 size_t used() const; | |
712 size_t free() const; | |
713 | |
714 MemRegion used_region() const; | |
715 | |
716 size_t unsafe_max_alloc_nogc() const; | |
717 size_t contiguous_available() const; | |
718 | |
719 // Iteration | |
720 void object_iterate(ObjectClosure* blk); | |
721 void space_iterate(SpaceClosure* blk, bool usedOnly = false); | |
722 | |
723 void younger_refs_iterate(OopsInGenClosure* blk); | |
724 | |
725 inline CompactibleSpace* first_compaction_space() const; | |
726 | |
727 virtual inline HeapWord* allocate(size_t word_size, bool is_tlab); | |
728 virtual inline HeapWord* par_allocate(size_t word_size, bool is_tlab); | |
729 | |
730 // Accessing marks | |
731 inline WaterMark top_mark(); | |
732 inline WaterMark bottom_mark(); | |
733 | |
734 #define OneContig_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ | |
735 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl); | |
736 OneContig_SINCE_SAVE_MARKS_DECL(OopsInGenClosure,_v) | |
737 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(OneContig_SINCE_SAVE_MARKS_DECL) | |
738 | |
739 void save_marks(); | |
740 void reset_saved_marks(); | |
741 bool no_allocs_since_save_marks(); | |
742 | |
743 inline size_t block_size(const HeapWord* addr) const; | |
744 | |
745 inline bool block_is_obj(const HeapWord* addr) const; | |
746 | |
747 virtual void collect(bool full, | |
748 bool clear_all_soft_refs, | |
749 size_t size, | |
750 bool is_tlab); | |
751 HeapWord* expand_and_allocate(size_t size, | |
752 bool is_tlab, | |
753 bool parallel = false); | |
754 | |
755 virtual void prepare_for_verify(); | |
756 | |
757 virtual void gc_epilogue(bool full); | |
758 | |
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759 virtual void record_spaces_top(); |
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760 |
6008 | 761 virtual void verify(); |
0 | 762 virtual void print_on(outputStream* st) const; |
763 }; | |
1972 | 764 |
765 #endif // SHARE_VM_MEMORY_GENERATION_HPP |