Mercurial > hg > truffle
annotate src/share/vm/memory/generation.hpp @ 4708:3c648b9ad052
7121373: Clean up CollectedHeap::is_in
Summary: Fixed G1CollectedHeap::is_in, added tests, cleaned up comments and made Space::is_in pure virtual.
Reviewed-by: brutisso, tonyp, jcoomes
| author | stefank |
|---|---|
| date | Wed, 14 Dec 2011 12:15:26 +0100 |
| parents | f95d63e2154a |
| children | e7dead7e90af |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 1972 | 2 * Copyright (c) 1997, 2010, 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 // - CompactingPermGenGen - reflective object area (klasses, methods, symbols, ...) | |
| 52 // - ConcurrentMarkSweepGeneration - Mostly Concurrent Mark Sweep Generation | |
| 53 // (Detlefs-Printezis refinement of | |
| 54 // Boehm-Demers-Schenker) | |
| 55 // | |
| 56 // The system configurations currently allowed are: | |
| 57 // | |
| 58 // DefNewGeneration + TenuredGeneration + PermGeneration | |
| 59 // DefNewGeneration + ConcurrentMarkSweepGeneration + ConcurrentMarkSweepPermGen | |
| 60 // | |
| 61 // ParNewGeneration + TenuredGeneration + PermGeneration | |
| 62 // ParNewGeneration + ConcurrentMarkSweepGeneration + ConcurrentMarkSweepPermGen | |
| 63 // | |
| 64 | |
| 65 class DefNewGeneration; | |
| 66 class GenerationSpec; | |
| 67 class CompactibleSpace; | |
| 68 class ContiguousSpace; | |
| 69 class CompactPoint; | |
| 70 class OopsInGenClosure; | |
| 71 class OopClosure; | |
| 72 class ScanClosure; | |
| 73 class FastScanClosure; | |
| 74 class GenCollectedHeap; | |
| 75 class GenRemSet; | |
| 76 class GCStats; | |
| 77 | |
| 78 // A "ScratchBlock" represents a block of memory in one generation usable by | |
| 79 // another. It represents "num_words" free words, starting at and including | |
| 80 // the address of "this". | |
| 81 struct ScratchBlock { | |
| 82 ScratchBlock* next; | |
| 83 size_t num_words; | |
| 84 HeapWord scratch_space[1]; // Actually, of size "num_words-2" (assuming | |
| 85 // first two fields are word-sized.) | |
| 86 }; | |
| 87 | |
| 88 | |
| 89 class Generation: public CHeapObj { | |
| 90 friend class VMStructs; | |
| 91 private: | |
| 92 jlong _time_of_last_gc; // time when last gc on this generation happened (ms) | |
| 93 MemRegion _prev_used_region; // for collectors that want to "remember" a value for | |
| 94 // used region at some specific point during collection. | |
| 95 | |
| 96 protected: | |
| 97 // Minimum and maximum addresses for memory reserved (not necessarily | |
| 98 // committed) for generation. | |
| 99 // Used by card marking code. Must not overlap with address ranges of | |
| 100 // other generations. | |
| 101 MemRegion _reserved; | |
| 102 | |
| 103 // Memory area reserved for generation | |
| 104 VirtualSpace _virtual_space; | |
| 105 | |
| 106 // Level in the generation hierarchy. | |
| 107 int _level; | |
| 108 | |
| 109 // ("Weak") Reference processing support | |
| 110 ReferenceProcessor* _ref_processor; | |
| 111 | |
| 112 // Performance Counters | |
| 113 CollectorCounters* _gc_counters; | |
| 114 | |
| 115 // Statistics for garbage collection | |
| 116 GCStats* _gc_stats; | |
| 117 | |
| 118 // Returns the next generation in the configuration, or else NULL if this | |
| 119 // is the highest generation. | |
| 120 Generation* next_gen() const; | |
| 121 | |
| 122 // Initialize the generation. | |
| 123 Generation(ReservedSpace rs, size_t initial_byte_size, int level); | |
| 124 | |
| 125 // Apply "cl->do_oop" to (the address of) (exactly) all the ref fields in | |
| 126 // "sp" that point into younger generations. | |
| 127 // The iteration is only over objects allocated at the start of the | |
| 128 // iterations; objects allocated as a result of applying the closure are | |
| 129 // not included. | |
| 130 void younger_refs_in_space_iterate(Space* sp, OopsInGenClosure* cl); | |
| 131 | |
| 132 public: | |
| 133 // The set of possible generation kinds. | |
| 134 enum Name { | |
| 135 ASParNew, | |
| 136 ASConcurrentMarkSweep, | |
| 137 DefNew, | |
| 138 ParNew, | |
| 139 MarkSweepCompact, | |
| 140 ConcurrentMarkSweep, | |
| 141 Other | |
| 142 }; | |
| 143 | |
| 144 enum SomePublicConstants { | |
| 145 // Generations are GenGrain-aligned and have size that are multiples of | |
| 146 // GenGrain. | |
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147 // Note: on ARM we add 1 bit for card_table_base to be properly aligned |
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148 // (we expect its low byte to be zero - see implementation of post_barrier) |
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149 LogOfGenGrain = 16 ARM_ONLY(+1), |
| 0 | 150 GenGrain = 1 << LogOfGenGrain |
| 151 }; | |
| 152 | |
| 153 // allocate and initialize ("weak") refs processing support | |
| 154 virtual void ref_processor_init(); | |
| 155 void set_ref_processor(ReferenceProcessor* rp) { | |
| 156 assert(_ref_processor == NULL, "clobbering existing _ref_processor"); | |
| 157 _ref_processor = rp; | |
| 158 } | |
| 159 | |
| 160 virtual Generation::Name kind() { return Generation::Other; } | |
| 161 GenerationSpec* spec(); | |
| 162 | |
| 163 // This properly belongs in the collector, but for now this | |
| 164 // will do. | |
| 165 virtual bool refs_discovery_is_atomic() const { return true; } | |
| 166 virtual bool refs_discovery_is_mt() const { return false; } | |
| 167 | |
| 168 // Space enquiries (results in bytes) | |
| 169 virtual size_t capacity() const = 0; // The maximum number of object bytes the | |
| 170 // generation can currently hold. | |
| 171 virtual size_t used() const = 0; // The number of used bytes in the gen. | |
| 172 virtual size_t free() const = 0; // The number of free bytes in the gen. | |
| 173 | |
| 174 // Support for java.lang.Runtime.maxMemory(); see CollectedHeap. | |
| 175 // Returns the total number of bytes available in a generation | |
| 176 // for the allocation of objects. | |
| 177 virtual size_t max_capacity() const; | |
| 178 | |
| 179 // If this is a young generation, the maximum number of bytes that can be | |
| 180 // allocated in this generation before a GC is triggered. | |
| 181 virtual size_t capacity_before_gc() const { return 0; } | |
| 182 | |
| 183 // The largest number of contiguous free bytes in the generation, | |
| 184 // including expansion (Assumes called at a safepoint.) | |
| 185 virtual size_t contiguous_available() const = 0; | |
| 186 // The largest number of contiguous free bytes in this or any higher generation. | |
| 187 virtual size_t max_contiguous_available() const; | |
| 188 | |
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189 // Returns true if promotions of the specified amount are |
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190 // likely to succeed without a promotion failure. |
| 0 | 191 // Promotion of the full amount is not guaranteed but |
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192 // might be attempted in the worst case. |
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193 virtual bool promotion_attempt_is_safe(size_t max_promotion_in_bytes) const; |
| 0 | 194 |
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195 // For a non-young generation, this interface can be used to inform a |
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196 // generation that a promotion attempt into that generation failed. |
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197 // Typically used to enable diagnostic output for post-mortem analysis, |
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198 // but other uses of the interface are not ruled out. |
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199 virtual void promotion_failure_occurred() { /* does nothing */ } |
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200 |
| 0 | 201 // Return an estimate of the maximum allocation that could be performed |
| 202 // in the generation without triggering any collection or expansion | |
| 203 // activity. It is "unsafe" because no locks are taken; the result | |
| 204 // should be treated as an approximation, not a guarantee, for use in | |
| 205 // heuristic resizing decisions. | |
| 206 virtual size_t unsafe_max_alloc_nogc() const = 0; | |
| 207 | |
| 208 // Returns true if this generation cannot be expanded further | |
| 209 // without a GC. Override as appropriate. | |
| 210 virtual bool is_maximal_no_gc() const { | |
| 211 return _virtual_space.uncommitted_size() == 0; | |
| 212 } | |
| 213 | |
| 214 MemRegion reserved() const { return _reserved; } | |
| 215 | |
| 216 // Returns a region guaranteed to contain all the objects in the | |
| 217 // generation. | |
| 218 virtual MemRegion used_region() const { return _reserved; } | |
| 219 | |
| 220 MemRegion prev_used_region() const { return _prev_used_region; } | |
| 221 virtual void save_used_region() { _prev_used_region = used_region(); } | |
| 222 | |
| 4708 | 223 // Returns "TRUE" iff "p" points into the committed areas in the generation. |
| 0 | 224 // For some kinds of generations, this may be an expensive operation. |
| 225 // To avoid performance problems stemming from its inadvertent use in | |
| 226 // product jvm's, we restrict its use to assertion checking or | |
| 227 // verification only. | |
| 228 virtual bool is_in(const void* p) const; | |
| 229 | |
| 230 /* Returns "TRUE" iff "p" points into the reserved area of the generation. */ | |
| 231 bool is_in_reserved(const void* p) const { | |
| 232 return _reserved.contains(p); | |
| 233 } | |
| 234 | |
| 235 // Check that the generation kind is DefNewGeneration or a sub | |
| 236 // class of DefNewGeneration and return a DefNewGeneration* | |
| 237 DefNewGeneration* as_DefNewGeneration(); | |
| 238 | |
| 239 // If some space in the generation contains the given "addr", return a | |
| 240 // pointer to that space, else return "NULL". | |
| 241 virtual Space* space_containing(const void* addr) const; | |
| 242 | |
| 243 // Iteration - do not use for time critical operations | |
| 244 virtual void space_iterate(SpaceClosure* blk, bool usedOnly = false) = 0; | |
| 245 | |
| 246 // Returns the first space, if any, in the generation that can participate | |
| 247 // in compaction, or else "NULL". | |
| 248 virtual CompactibleSpace* first_compaction_space() const = 0; | |
| 249 | |
| 250 // Returns "true" iff this generation should be used to allocate an | |
| 251 // object of the given size. Young generations might | |
| 252 // wish to exclude very large objects, for example, since, if allocated | |
| 253 // often, they would greatly increase the frequency of young-gen | |
| 254 // collection. | |
| 255 virtual bool should_allocate(size_t word_size, bool is_tlab) { | |
| 256 bool result = false; | |
| 257 size_t overflow_limit = (size_t)1 << (BitsPerSize_t - LogHeapWordSize); | |
| 258 if (!is_tlab || supports_tlab_allocation()) { | |
| 259 result = (word_size > 0) && (word_size < overflow_limit); | |
| 260 } | |
| 261 return result; | |
| 262 } | |
| 263 | |
| 264 // Allocate and returns a block of the requested size, or returns "NULL". | |
| 265 // Assumes the caller has done any necessary locking. | |
| 266 virtual HeapWord* allocate(size_t word_size, bool is_tlab) = 0; | |
| 267 | |
| 268 // Like "allocate", but performs any necessary locking internally. | |
| 269 virtual HeapWord* par_allocate(size_t word_size, bool is_tlab) = 0; | |
| 270 | |
| 271 // A 'younger' gen has reached an allocation limit, and uses this to notify | |
| 272 // the next older gen. The return value is a new limit, or NULL if none. The | |
| 273 // caller must do the necessary locking. | |
| 274 virtual HeapWord* allocation_limit_reached(Space* space, HeapWord* top, | |
| 275 size_t word_size) { | |
| 276 return NULL; | |
| 277 } | |
| 278 | |
| 279 // Some generation may offer a region for shared, contiguous allocation, | |
| 280 // via inlined code (by exporting the address of the top and end fields | |
| 281 // defining the extent of the contiguous allocation region.) | |
| 282 | |
| 283 // This function returns "true" iff the heap supports this kind of | |
| 284 // allocation. (More precisely, this means the style of allocation that | |
| 285 // increments *top_addr()" with a CAS.) (Default is "no".) | |
| 286 // A generation that supports this allocation style must use lock-free | |
| 287 // allocation for *all* allocation, since there are times when lock free | |
| 288 // allocation will be concurrent with plain "allocate" calls. | |
| 289 virtual bool supports_inline_contig_alloc() const { return false; } | |
| 290 | |
| 291 // These functions return the addresses of the fields that define the | |
| 292 // boundaries of the contiguous allocation area. (These fields should be | |
| 293 // physicall near to one another.) | |
| 294 virtual HeapWord** top_addr() const { return NULL; } | |
| 295 virtual HeapWord** end_addr() const { return NULL; } | |
| 296 | |
| 297 // Thread-local allocation buffers | |
| 298 virtual bool supports_tlab_allocation() const { return false; } | |
| 299 virtual size_t tlab_capacity() const { | |
| 300 guarantee(false, "Generation doesn't support thread local allocation buffers"); | |
| 301 return 0; | |
| 302 } | |
| 303 virtual size_t unsafe_max_tlab_alloc() const { | |
| 304 guarantee(false, "Generation doesn't support thread local allocation buffers"); | |
| 305 return 0; | |
| 306 } | |
| 307 | |
| 308 // "obj" is the address of an object in a younger generation. Allocate space | |
| 309 // for "obj" in the current (or some higher) generation, and copy "obj" into | |
| 310 // the newly allocated space, if possible, returning the result (or NULL if | |
| 311 // the allocation failed). | |
| 312 // | |
| 313 // The "obj_size" argument is just obj->size(), passed along so the caller can | |
| 314 // avoid repeating the virtual call to retrieve it. | |
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315 virtual oop promote(oop obj, size_t obj_size); |
| 0 | 316 |
| 317 // Thread "thread_num" (0 <= i < ParalleGCThreads) wants to promote | |
| 318 // object "obj", whose original mark word was "m", and whose size is | |
| 319 // "word_sz". If possible, allocate space for "obj", copy obj into it | |
| 320 // (taking care to copy "m" into the mark word when done, since the mark | |
| 321 // word of "obj" may have been overwritten with a forwarding pointer, and | |
| 322 // also taking care to copy the klass pointer *last*. Returns the new | |
| 323 // object if successful, or else NULL. | |
| 324 virtual oop par_promote(int thread_num, | |
| 325 oop obj, markOop m, size_t word_sz); | |
| 326 | |
| 327 // Undo, if possible, the most recent par_promote_alloc allocation by | |
| 328 // "thread_num" ("obj", of "word_sz"). | |
| 329 virtual void par_promote_alloc_undo(int thread_num, | |
| 330 HeapWord* obj, size_t word_sz); | |
| 331 | |
| 332 // Informs the current generation that all par_promote_alloc's in the | |
| 333 // collection have been completed; any supporting data structures can be | |
| 334 // reset. Default is to do nothing. | |
| 335 virtual void par_promote_alloc_done(int thread_num) {} | |
| 336 | |
| 337 // Informs the current generation that all oop_since_save_marks_iterates | |
| 338 // performed by "thread_num" in the current collection, if any, have been | |
| 339 // completed; any supporting data structures can be reset. Default is to | |
| 340 // do nothing. | |
| 341 virtual void par_oop_since_save_marks_iterate_done(int thread_num) {} | |
| 342 | |
| 343 // This generation will collect all younger generations | |
| 344 // during a full collection. | |
| 345 virtual bool full_collects_younger_generations() const { return false; } | |
| 346 | |
| 347 // This generation does in-place marking, meaning that mark words | |
| 348 // are mutated during the marking phase and presumably reinitialized | |
| 349 // to a canonical value after the GC. This is currently used by the | |
| 350 // biased locking implementation to determine whether additional | |
| 351 // work is required during the GC prologue and epilogue. | |
| 352 virtual bool performs_in_place_marking() const { return true; } | |
| 353 | |
| 354 // Returns "true" iff collect() should subsequently be called on this | |
| 355 // this generation. See comment below. | |
| 356 // This is a generic implementation which can be overridden. | |
| 357 // | |
| 358 // Note: in the current (1.4) implementation, when genCollectedHeap's | |
| 359 // incremental_collection_will_fail flag is set, all allocations are | |
| 360 // slow path (the only fast-path place to allocate is DefNew, which | |
| 361 // will be full if the flag is set). | |
| 362 // Thus, older generations which collect younger generations should | |
| 363 // test this flag and collect if it is set. | |
| 364 virtual bool should_collect(bool full, | |
| 365 size_t word_size, | |
| 366 bool is_tlab) { | |
| 367 return (full || should_allocate(word_size, is_tlab)); | |
| 368 } | |
| 369 | |
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370 // Returns true if the collection is likely to be safely |
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371 // completed. Even if this method returns true, a collection |
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372 // may not be guaranteed to succeed, and the system should be |
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373 // able to safely unwind and recover from that failure, albeit |
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374 // at some additional cost. |
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375 virtual bool collection_attempt_is_safe() { |
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376 guarantee(false, "Are you sure you want to call this method?"); |
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377 return true; |
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378 } |
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379 |
| 0 | 380 // Perform a garbage collection. |
| 381 // If full is true attempt a full garbage collection of this generation. | |
| 382 // Otherwise, attempting to (at least) free enough space to support an | |
| 383 // allocation of the given "word_size". | |
| 384 virtual void collect(bool full, | |
| 385 bool clear_all_soft_refs, | |
| 386 size_t word_size, | |
| 387 bool is_tlab) = 0; | |
| 388 | |
| 389 // Perform a heap collection, attempting to create (at least) enough | |
| 390 // space to support an allocation of the given "word_size". If | |
| 391 // successful, perform the allocation and return the resulting | |
| 392 // "oop" (initializing the allocated block). If the allocation is | |
| 393 // still unsuccessful, return "NULL". | |
| 394 virtual HeapWord* expand_and_allocate(size_t word_size, | |
| 395 bool is_tlab, | |
| 396 bool parallel = false) = 0; | |
| 397 | |
| 398 // Some generations may require some cleanup or preparation actions before | |
| 399 // allowing a collection. The default is to do nothing. | |
| 400 virtual void gc_prologue(bool full) {}; | |
| 401 | |
| 402 // Some generations may require some cleanup actions after a collection. | |
| 403 // The default is to do nothing. | |
| 404 virtual void gc_epilogue(bool full) {}; | |
| 405 | |
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406 // Save the high water marks for the used space in a generation. |
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407 virtual void record_spaces_top() {}; |
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408 |
| 0 | 409 // Some generations may need to be "fixed-up" after some allocation |
| 410 // activity to make them parsable again. The default is to do nothing. | |
| 411 virtual void ensure_parsability() {}; | |
| 412 | |
| 413 // Time (in ms) when we were last collected or now if a collection is | |
| 414 // in progress. | |
| 415 virtual jlong time_of_last_gc(jlong now) { | |
| 416 // XXX See note in genCollectedHeap::millis_since_last_gc() | |
| 417 NOT_PRODUCT( | |
| 418 if (now < _time_of_last_gc) { | |
| 419 warning("time warp: %d to %d", _time_of_last_gc, now); | |
| 420 } | |
| 421 ) | |
| 422 return _time_of_last_gc; | |
| 423 } | |
| 424 | |
| 425 virtual void update_time_of_last_gc(jlong now) { | |
| 426 _time_of_last_gc = now; | |
| 427 } | |
| 428 | |
| 429 // Generations may keep statistics about collection. This | |
| 430 // method updates those statistics. current_level is | |
| 431 // the level of the collection that has most recently | |
| 432 // occurred. This allows the generation to decide what | |
| 433 // statistics are valid to collect. For example, the | |
| 434 // generation can decide to gather the amount of promoted data | |
| 435 // if the collection of the younger generations has completed. | |
| 436 GCStats* gc_stats() const { return _gc_stats; } | |
| 437 virtual void update_gc_stats(int current_level, bool full) {} | |
| 438 | |
| 439 // Mark sweep support phase2 | |
| 440 virtual void prepare_for_compaction(CompactPoint* cp); | |
| 441 // Mark sweep support phase3 | |
| 442 virtual void pre_adjust_pointers() {ShouldNotReachHere();} | |
| 443 virtual void adjust_pointers(); | |
| 444 // Mark sweep support phase4 | |
| 445 virtual void compact(); | |
| 446 virtual void post_compact() {ShouldNotReachHere();} | |
| 447 | |
| 448 // Support for CMS's rescan. In this general form we return a pointer | |
| 449 // to an abstract object that can be used, based on specific previously | |
| 450 // decided protocols, to exchange information between generations, | |
| 451 // information that may be useful for speeding up certain types of | |
| 452 // garbage collectors. A NULL value indicates to the client that | |
| 453 // no data recording is expected by the provider. The data-recorder is | |
| 454 // expected to be GC worker thread-local, with the worker index | |
| 455 // indicated by "thr_num". | |
| 456 virtual void* get_data_recorder(int thr_num) { return NULL; } | |
| 457 | |
| 458 // Some generations may require some cleanup actions before allowing | |
| 459 // a verification. | |
| 460 virtual void prepare_for_verify() {}; | |
| 461 | |
| 462 // Accessing "marks". | |
| 463 | |
| 464 // This function gives a generation a chance to note a point between | |
| 465 // collections. For example, a contiguous generation might note the | |
| 466 // beginning allocation point post-collection, which might allow some later | |
| 467 // operations to be optimized. | |
| 468 virtual void save_marks() {} | |
| 469 | |
| 470 // This function allows generations to initialize any "saved marks". That | |
| 471 // is, should only be called when the generation is empty. | |
| 472 virtual void reset_saved_marks() {} | |
| 473 | |
| 474 // This function is "true" iff any no allocations have occurred in the | |
| 475 // generation since the last call to "save_marks". | |
| 476 virtual bool no_allocs_since_save_marks() = 0; | |
| 477 | |
| 478 // Apply "cl->apply" to (the addresses of) all reference fields in objects | |
| 479 // allocated in the current generation since the last call to "save_marks". | |
| 480 // If more objects are allocated in this generation as a result of applying | |
| 481 // the closure, iterates over reference fields in those objects as well. | |
| 482 // Calls "save_marks" at the end of the iteration. | |
| 483 // General signature... | |
| 484 virtual void oop_since_save_marks_iterate_v(OopsInGenClosure* cl) = 0; | |
| 485 // ...and specializations for de-virtualization. (The general | |
| 486 // implemention of the _nv versions call the virtual version. | |
| 487 // Note that the _nv suffix is not really semantically necessary, | |
| 488 // but it avoids some not-so-useful warnings on Solaris.) | |
| 489 #define Generation_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ | |
| 490 virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \ | |
| 491 oop_since_save_marks_iterate_v((OopsInGenClosure*)cl); \ | |
| 492 } | |
| 493 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(Generation_SINCE_SAVE_MARKS_DECL) | |
| 494 | |
| 495 #undef Generation_SINCE_SAVE_MARKS_DECL | |
| 496 | |
| 497 // The "requestor" generation is performing some garbage collection | |
| 498 // action for which it would be useful to have scratch space. If | |
| 499 // the target is not the requestor, no gc actions will be required | |
| 500 // of the target. The requestor promises to allocate no more than | |
| 501 // "max_alloc_words" in the target generation (via promotion say, | |
| 502 // if the requestor is a young generation and the target is older). | |
| 503 // If the target generation can provide any scratch space, it adds | |
| 504 // it to "list", leaving "list" pointing to the head of the | |
| 505 // augmented list. The default is to offer no space. | |
| 506 virtual void contribute_scratch(ScratchBlock*& list, Generation* requestor, | |
| 507 size_t max_alloc_words) {} | |
| 508 | |
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509 // Give each generation an opportunity to do clean up for any |
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510 // contributed scratch. |
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511 virtual void reset_scratch() {}; |
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512 |
| 0 | 513 // When an older generation has been collected, and perhaps resized, |
| 514 // this method will be invoked on all younger generations (from older to | |
| 515 // younger), allowing them to resize themselves as appropriate. | |
| 516 virtual void compute_new_size() = 0; | |
| 517 | |
| 518 // Printing | |
| 519 virtual const char* name() const = 0; | |
| 520 virtual const char* short_name() const = 0; | |
| 521 | |
| 522 int level() const { return _level; } | |
| 523 | |
| 524 // Attributes | |
| 525 | |
| 526 // True iff the given generation may only be the youngest generation. | |
| 527 virtual bool must_be_youngest() const = 0; | |
| 528 // True iff the given generation may only be the oldest generation. | |
| 529 virtual bool must_be_oldest() const = 0; | |
| 530 | |
| 531 // Reference Processing accessor | |
| 532 ReferenceProcessor* const ref_processor() { return _ref_processor; } | |
| 533 | |
| 534 // Iteration. | |
| 535 | |
| 536 // Iterate over all the ref-containing fields of all objects in the | |
| 537 // generation, calling "cl.do_oop" on each. | |
| 538 virtual void oop_iterate(OopClosure* cl); | |
| 539 | |
| 540 // Same as above, restricted to the intersection of a memory region and | |
| 541 // the generation. | |
| 542 virtual void oop_iterate(MemRegion mr, OopClosure* cl); | |
| 543 | |
| 544 // Iterate over all objects in the generation, calling "cl.do_object" on | |
| 545 // each. | |
| 546 virtual void object_iterate(ObjectClosure* cl); | |
| 547 | |
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548 // Iterate over all safe objects in the generation, calling "cl.do_object" on |
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549 // each. An object is safe if its references point to other objects in |
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550 // the heap. This defaults to object_iterate() unless overridden. |
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551 virtual void safe_object_iterate(ObjectClosure* cl); |
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552 |
| 0 | 553 // Iterate over all objects allocated in the generation since the last |
| 554 // collection, calling "cl.do_object" on each. The generation must have | |
| 555 // been initialized properly to support this function, or else this call | |
| 556 // will fail. | |
| 557 virtual void object_iterate_since_last_GC(ObjectClosure* cl) = 0; | |
| 558 | |
| 559 // Apply "cl->do_oop" to (the address of) all and only all the ref fields | |
| 560 // in the current generation that contain pointers to objects in younger | |
| 561 // generations. Objects allocated since the last "save_marks" call are | |
| 562 // excluded. | |
| 563 virtual void younger_refs_iterate(OopsInGenClosure* cl) = 0; | |
| 564 | |
| 565 // Inform a generation that it longer contains references to objects | |
| 566 // in any younger generation. [e.g. Because younger gens are empty, | |
| 567 // clear the card table.] | |
| 568 virtual void clear_remembered_set() { } | |
| 569 | |
| 570 // Inform a generation that some of its objects have moved. [e.g. The | |
| 571 // generation's spaces were compacted, invalidating the card table.] | |
| 572 virtual void invalidate_remembered_set() { } | |
| 573 | |
| 574 // Block abstraction. | |
| 575 | |
| 576 // Returns the address of the start of the "block" that contains the | |
| 577 // address "addr". We say "blocks" instead of "object" since some heaps | |
| 578 // may not pack objects densely; a chunk may either be an object or a | |
| 579 // non-object. | |
| 580 virtual HeapWord* block_start(const void* addr) const; | |
| 581 | |
| 582 // Requires "addr" to be the start of a chunk, and returns its size. | |
| 583 // "addr + size" is required to be the start of a new chunk, or the end | |
| 584 // of the active area of the heap. | |
| 585 virtual size_t block_size(const HeapWord* addr) const ; | |
| 586 | |
| 587 // Requires "addr" to be the start of a block, and returns "TRUE" iff | |
| 588 // the block is an object. | |
| 589 virtual bool block_is_obj(const HeapWord* addr) const; | |
| 590 | |
| 591 | |
| 592 // PrintGC, PrintGCDetails support | |
| 593 void print_heap_change(size_t prev_used) const; | |
| 594 | |
| 595 // PrintHeapAtGC support | |
| 596 virtual void print() const; | |
| 597 virtual void print_on(outputStream* st) const; | |
| 598 | |
| 599 virtual void verify(bool allow_dirty) = 0; | |
| 600 | |
| 601 struct StatRecord { | |
| 602 int invocations; | |
| 603 elapsedTimer accumulated_time; | |
| 604 StatRecord() : | |
| 605 invocations(0), | |
| 606 accumulated_time(elapsedTimer()) {} | |
| 607 }; | |
| 608 private: | |
| 609 StatRecord _stat_record; | |
| 610 public: | |
| 611 StatRecord* stat_record() { return &_stat_record; } | |
| 612 | |
| 613 virtual void print_summary_info(); | |
| 614 virtual void print_summary_info_on(outputStream* st); | |
| 615 | |
| 616 // Performance Counter support | |
| 617 virtual void update_counters() = 0; | |
| 618 virtual CollectorCounters* counters() { return _gc_counters; } | |
| 619 }; | |
| 620 | |
| 621 // Class CardGeneration is a generation that is covered by a card table, | |
| 622 // and uses a card-size block-offset array to implement block_start. | |
| 623 | |
| 624 // class BlockOffsetArray; | |
| 625 // class BlockOffsetArrayContigSpace; | |
| 626 class BlockOffsetSharedArray; | |
| 627 | |
| 628 class CardGeneration: public Generation { | |
| 629 friend class VMStructs; | |
| 630 protected: | |
| 631 // This is shared with other generations. | |
| 632 GenRemSet* _rs; | |
| 633 // This is local to this generation. | |
| 634 BlockOffsetSharedArray* _bts; | |
| 635 | |
| 636 CardGeneration(ReservedSpace rs, size_t initial_byte_size, int level, | |
| 637 GenRemSet* remset); | |
| 638 | |
| 639 public: | |
| 640 | |
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641 // Attempt to expand the generation by "bytes". Expand by at a |
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642 // minimum "expand_bytes". Return true if some amount (not |
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643 // necessarily the full "bytes") was done. |
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644 virtual bool expand(size_t bytes, size_t expand_bytes); |
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645 |
| 0 | 646 virtual void clear_remembered_set(); |
| 647 | |
| 648 virtual void invalidate_remembered_set(); | |
| 649 | |
| 650 virtual void prepare_for_verify(); | |
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651 |
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652 // Grow generation with specified size (returns false if unable to grow) |
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653 virtual bool grow_by(size_t bytes) = 0; |
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654 // Grow generation to reserved size. |
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655 virtual bool grow_to_reserved() = 0; |
| 0 | 656 }; |
| 657 | |
| 658 // OneContigSpaceCardGeneration models a heap of old objects contained in a single | |
| 659 // contiguous space. | |
| 660 // | |
| 661 // Garbage collection is performed using mark-compact. | |
| 662 | |
| 663 class OneContigSpaceCardGeneration: public CardGeneration { | |
| 664 friend class VMStructs; | |
| 665 // Abstractly, this is a subtype that gets access to protected fields. | |
| 666 friend class CompactingPermGen; | |
| 667 friend class VM_PopulateDumpSharedSpace; | |
| 668 | |
| 669 protected: | |
| 670 size_t _min_heap_delta_bytes; // Minimum amount to expand. | |
| 671 ContiguousSpace* _the_space; // actual space holding objects | |
| 672 WaterMark _last_gc; // watermark between objects allocated before | |
| 673 // and after last GC. | |
| 674 | |
| 675 // Grow generation with specified size (returns false if unable to grow) | |
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676 virtual bool grow_by(size_t bytes); |
| 0 | 677 // Grow generation to reserved size. |
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678 virtual bool grow_to_reserved(); |
| 0 | 679 // Shrink generation with specified size (returns false if unable to shrink) |
| 680 void shrink_by(size_t bytes); | |
| 681 | |
| 682 // Allocation failure | |
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683 virtual bool expand(size_t bytes, size_t expand_bytes); |
| 0 | 684 void shrink(size_t bytes); |
| 685 | |
| 686 // Accessing spaces | |
| 687 ContiguousSpace* the_space() const { return _the_space; } | |
| 688 | |
| 689 public: | |
| 690 OneContigSpaceCardGeneration(ReservedSpace rs, size_t initial_byte_size, | |
| 691 size_t min_heap_delta_bytes, | |
| 692 int level, GenRemSet* remset, | |
| 693 ContiguousSpace* space) : | |
| 694 CardGeneration(rs, initial_byte_size, level, remset), | |
| 695 _the_space(space), _min_heap_delta_bytes(min_heap_delta_bytes) | |
| 696 {} | |
| 697 | |
| 698 inline bool is_in(const void* p) const; | |
| 699 | |
| 700 // Space enquiries | |
| 701 size_t capacity() const; | |
| 702 size_t used() const; | |
| 703 size_t free() const; | |
| 704 | |
| 705 MemRegion used_region() const; | |
| 706 | |
| 707 size_t unsafe_max_alloc_nogc() const; | |
| 708 size_t contiguous_available() const; | |
| 709 | |
| 710 // Iteration | |
| 711 void object_iterate(ObjectClosure* blk); | |
| 712 void space_iterate(SpaceClosure* blk, bool usedOnly = false); | |
| 713 void object_iterate_since_last_GC(ObjectClosure* cl); | |
| 714 | |
| 715 void younger_refs_iterate(OopsInGenClosure* blk); | |
| 716 | |
| 717 inline CompactibleSpace* first_compaction_space() const; | |
| 718 | |
| 719 virtual inline HeapWord* allocate(size_t word_size, bool is_tlab); | |
| 720 virtual inline HeapWord* par_allocate(size_t word_size, bool is_tlab); | |
| 721 | |
| 722 // Accessing marks | |
| 723 inline WaterMark top_mark(); | |
| 724 inline WaterMark bottom_mark(); | |
| 725 | |
| 726 #define OneContig_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ | |
| 727 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl); | |
| 728 OneContig_SINCE_SAVE_MARKS_DECL(OopsInGenClosure,_v) | |
| 729 SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(OneContig_SINCE_SAVE_MARKS_DECL) | |
| 730 | |
| 731 void save_marks(); | |
| 732 void reset_saved_marks(); | |
| 733 bool no_allocs_since_save_marks(); | |
| 734 | |
| 735 inline size_t block_size(const HeapWord* addr) const; | |
| 736 | |
| 737 inline bool block_is_obj(const HeapWord* addr) const; | |
| 738 | |
| 739 virtual void collect(bool full, | |
| 740 bool clear_all_soft_refs, | |
| 741 size_t size, | |
| 742 bool is_tlab); | |
| 743 HeapWord* expand_and_allocate(size_t size, | |
| 744 bool is_tlab, | |
| 745 bool parallel = false); | |
| 746 | |
| 747 virtual void prepare_for_verify(); | |
| 748 | |
| 749 virtual void gc_epilogue(bool full); | |
| 750 | |
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751 virtual void record_spaces_top(); |
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752 |
| 0 | 753 virtual void verify(bool allow_dirty); |
| 754 virtual void print_on(outputStream* st) const; | |
| 755 }; | |
| 1972 | 756 |
| 757 #endif // SHARE_VM_MEMORY_GENERATION_HPP |