Wed, 26 Jun 2013 16:58:37 +0200
8013590: NPG: Add a memory pool MXBean for Metaspace
Reviewed-by: jmasa, mgerdin
duke@435 | 1 | /* |
brutisso@3711 | 2 | * Copyright (c) 1997, 2012, Oracle and/or its affiliates. All rights reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
trims@1907 | 19 | * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
trims@1907 | 20 | * or visit www.oracle.com if you need additional information or have any |
trims@1907 | 21 | * questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
stefank@2314 | 25 | #ifndef SHARE_VM_MEMORY_GENERATION_HPP |
stefank@2314 | 26 | #define SHARE_VM_MEMORY_GENERATION_HPP |
stefank@2314 | 27 | |
stefank@2314 | 28 | #include "gc_implementation/shared/collectorCounters.hpp" |
stefank@2314 | 29 | #include "memory/allocation.hpp" |
stefank@2314 | 30 | #include "memory/memRegion.hpp" |
stefank@2314 | 31 | #include "memory/referenceProcessor.hpp" |
stefank@2314 | 32 | #include "memory/universe.hpp" |
stefank@2314 | 33 | #include "memory/watermark.hpp" |
stefank@2314 | 34 | #include "runtime/mutex.hpp" |
stefank@2314 | 35 | #include "runtime/perfData.hpp" |
stefank@2314 | 36 | #include "runtime/virtualspace.hpp" |
stefank@2314 | 37 | |
duke@435 | 38 | // A Generation models a heap area for similarly-aged objects. |
duke@435 | 39 | // It will contain one ore more spaces holding the actual objects. |
duke@435 | 40 | // |
duke@435 | 41 | // The Generation class hierarchy: |
duke@435 | 42 | // |
duke@435 | 43 | // Generation - abstract base class |
duke@435 | 44 | // - DefNewGeneration - allocation area (copy collected) |
duke@435 | 45 | // - ParNewGeneration - a DefNewGeneration that is collected by |
duke@435 | 46 | // several threads |
duke@435 | 47 | // - CardGeneration - abstract class adding offset array behavior |
duke@435 | 48 | // - OneContigSpaceCardGeneration - abstract class holding a single |
duke@435 | 49 | // contiguous space with card marking |
duke@435 | 50 | // - TenuredGeneration - tenured (old object) space (markSweepCompact) |
duke@435 | 51 | // - ConcurrentMarkSweepGeneration - Mostly Concurrent Mark Sweep Generation |
duke@435 | 52 | // (Detlefs-Printezis refinement of |
duke@435 | 53 | // Boehm-Demers-Schenker) |
duke@435 | 54 | // |
duke@435 | 55 | // The system configurations currently allowed are: |
duke@435 | 56 | // |
coleenp@4037 | 57 | // DefNewGeneration + TenuredGeneration |
coleenp@4037 | 58 | // DefNewGeneration + ConcurrentMarkSweepGeneration |
duke@435 | 59 | // |
coleenp@4037 | 60 | // ParNewGeneration + TenuredGeneration |
coleenp@4037 | 61 | // ParNewGeneration + ConcurrentMarkSweepGeneration |
duke@435 | 62 | // |
duke@435 | 63 | |
duke@435 | 64 | class DefNewGeneration; |
duke@435 | 65 | class GenerationSpec; |
duke@435 | 66 | class CompactibleSpace; |
duke@435 | 67 | class ContiguousSpace; |
duke@435 | 68 | class CompactPoint; |
duke@435 | 69 | class OopsInGenClosure; |
duke@435 | 70 | class OopClosure; |
duke@435 | 71 | class ScanClosure; |
duke@435 | 72 | class FastScanClosure; |
duke@435 | 73 | class GenCollectedHeap; |
duke@435 | 74 | class GenRemSet; |
duke@435 | 75 | class GCStats; |
duke@435 | 76 | |
duke@435 | 77 | // A "ScratchBlock" represents a block of memory in one generation usable by |
duke@435 | 78 | // another. It represents "num_words" free words, starting at and including |
duke@435 | 79 | // the address of "this". |
duke@435 | 80 | struct ScratchBlock { |
duke@435 | 81 | ScratchBlock* next; |
duke@435 | 82 | size_t num_words; |
duke@435 | 83 | HeapWord scratch_space[1]; // Actually, of size "num_words-2" (assuming |
duke@435 | 84 | // first two fields are word-sized.) |
duke@435 | 85 | }; |
duke@435 | 86 | |
duke@435 | 87 | |
zgu@3900 | 88 | class Generation: public CHeapObj<mtGC> { |
duke@435 | 89 | friend class VMStructs; |
duke@435 | 90 | private: |
duke@435 | 91 | jlong _time_of_last_gc; // time when last gc on this generation happened (ms) |
duke@435 | 92 | MemRegion _prev_used_region; // for collectors that want to "remember" a value for |
duke@435 | 93 | // used region at some specific point during collection. |
duke@435 | 94 | |
duke@435 | 95 | protected: |
duke@435 | 96 | // Minimum and maximum addresses for memory reserved (not necessarily |
duke@435 | 97 | // committed) for generation. |
duke@435 | 98 | // Used by card marking code. Must not overlap with address ranges of |
duke@435 | 99 | // other generations. |
duke@435 | 100 | MemRegion _reserved; |
duke@435 | 101 | |
duke@435 | 102 | // Memory area reserved for generation |
duke@435 | 103 | VirtualSpace _virtual_space; |
duke@435 | 104 | |
duke@435 | 105 | // Level in the generation hierarchy. |
duke@435 | 106 | int _level; |
duke@435 | 107 | |
duke@435 | 108 | // ("Weak") Reference processing support |
duke@435 | 109 | ReferenceProcessor* _ref_processor; |
duke@435 | 110 | |
duke@435 | 111 | // Performance Counters |
duke@435 | 112 | CollectorCounters* _gc_counters; |
duke@435 | 113 | |
duke@435 | 114 | // Statistics for garbage collection |
duke@435 | 115 | GCStats* _gc_stats; |
duke@435 | 116 | |
duke@435 | 117 | // Returns the next generation in the configuration, or else NULL if this |
duke@435 | 118 | // is the highest generation. |
duke@435 | 119 | Generation* next_gen() const; |
duke@435 | 120 | |
duke@435 | 121 | // Initialize the generation. |
duke@435 | 122 | Generation(ReservedSpace rs, size_t initial_byte_size, int level); |
duke@435 | 123 | |
duke@435 | 124 | // Apply "cl->do_oop" to (the address of) (exactly) all the ref fields in |
duke@435 | 125 | // "sp" that point into younger generations. |
duke@435 | 126 | // The iteration is only over objects allocated at the start of the |
duke@435 | 127 | // iterations; objects allocated as a result of applying the closure are |
duke@435 | 128 | // not included. |
duke@435 | 129 | void younger_refs_in_space_iterate(Space* sp, OopsInGenClosure* cl); |
duke@435 | 130 | |
duke@435 | 131 | public: |
duke@435 | 132 | // The set of possible generation kinds. |
duke@435 | 133 | enum Name { |
duke@435 | 134 | ASParNew, |
duke@435 | 135 | ASConcurrentMarkSweep, |
duke@435 | 136 | DefNew, |
duke@435 | 137 | ParNew, |
duke@435 | 138 | MarkSweepCompact, |
duke@435 | 139 | ConcurrentMarkSweep, |
duke@435 | 140 | Other |
duke@435 | 141 | }; |
duke@435 | 142 | |
duke@435 | 143 | enum SomePublicConstants { |
duke@435 | 144 | // Generations are GenGrain-aligned and have size that are multiples of |
duke@435 | 145 | // GenGrain. |
bobv@2036 | 146 | // Note: on ARM we add 1 bit for card_table_base to be properly aligned |
bobv@2036 | 147 | // (we expect its low byte to be zero - see implementation of post_barrier) |
bobv@2036 | 148 | LogOfGenGrain = 16 ARM_ONLY(+1), |
duke@435 | 149 | GenGrain = 1 << LogOfGenGrain |
duke@435 | 150 | }; |
duke@435 | 151 | |
duke@435 | 152 | // allocate and initialize ("weak") refs processing support |
duke@435 | 153 | virtual void ref_processor_init(); |
duke@435 | 154 | void set_ref_processor(ReferenceProcessor* rp) { |
duke@435 | 155 | assert(_ref_processor == NULL, "clobbering existing _ref_processor"); |
duke@435 | 156 | _ref_processor = rp; |
duke@435 | 157 | } |
duke@435 | 158 | |
duke@435 | 159 | virtual Generation::Name kind() { return Generation::Other; } |
duke@435 | 160 | GenerationSpec* spec(); |
duke@435 | 161 | |
duke@435 | 162 | // This properly belongs in the collector, but for now this |
duke@435 | 163 | // will do. |
duke@435 | 164 | virtual bool refs_discovery_is_atomic() const { return true; } |
duke@435 | 165 | virtual bool refs_discovery_is_mt() const { return false; } |
duke@435 | 166 | |
duke@435 | 167 | // Space enquiries (results in bytes) |
duke@435 | 168 | virtual size_t capacity() const = 0; // The maximum number of object bytes the |
duke@435 | 169 | // generation can currently hold. |
duke@435 | 170 | virtual size_t used() const = 0; // The number of used bytes in the gen. |
duke@435 | 171 | virtual size_t free() const = 0; // The number of free bytes in the gen. |
duke@435 | 172 | |
duke@435 | 173 | // Support for java.lang.Runtime.maxMemory(); see CollectedHeap. |
duke@435 | 174 | // Returns the total number of bytes available in a generation |
duke@435 | 175 | // for the allocation of objects. |
duke@435 | 176 | virtual size_t max_capacity() const; |
duke@435 | 177 | |
duke@435 | 178 | // If this is a young generation, the maximum number of bytes that can be |
duke@435 | 179 | // allocated in this generation before a GC is triggered. |
duke@435 | 180 | virtual size_t capacity_before_gc() const { return 0; } |
duke@435 | 181 | |
duke@435 | 182 | // The largest number of contiguous free bytes in the generation, |
duke@435 | 183 | // including expansion (Assumes called at a safepoint.) |
duke@435 | 184 | virtual size_t contiguous_available() const = 0; |
duke@435 | 185 | // The largest number of contiguous free bytes in this or any higher generation. |
duke@435 | 186 | virtual size_t max_contiguous_available() const; |
duke@435 | 187 | |
ysr@2243 | 188 | // Returns true if promotions of the specified amount are |
ysr@2243 | 189 | // likely to succeed without a promotion failure. |
duke@435 | 190 | // Promotion of the full amount is not guaranteed but |
ysr@2243 | 191 | // might be attempted in the worst case. |
ysr@2243 | 192 | virtual bool promotion_attempt_is_safe(size_t max_promotion_in_bytes) const; |
duke@435 | 193 | |
ysr@1580 | 194 | // For a non-young generation, this interface can be used to inform a |
ysr@1580 | 195 | // generation that a promotion attempt into that generation failed. |
ysr@1580 | 196 | // Typically used to enable diagnostic output for post-mortem analysis, |
ysr@1580 | 197 | // but other uses of the interface are not ruled out. |
ysr@1580 | 198 | virtual void promotion_failure_occurred() { /* does nothing */ } |
ysr@1580 | 199 | |
duke@435 | 200 | // Return an estimate of the maximum allocation that could be performed |
duke@435 | 201 | // in the generation without triggering any collection or expansion |
duke@435 | 202 | // activity. It is "unsafe" because no locks are taken; the result |
duke@435 | 203 | // should be treated as an approximation, not a guarantee, for use in |
duke@435 | 204 | // heuristic resizing decisions. |
duke@435 | 205 | virtual size_t unsafe_max_alloc_nogc() const = 0; |
duke@435 | 206 | |
duke@435 | 207 | // Returns true if this generation cannot be expanded further |
duke@435 | 208 | // without a GC. Override as appropriate. |
duke@435 | 209 | virtual bool is_maximal_no_gc() const { |
duke@435 | 210 | return _virtual_space.uncommitted_size() == 0; |
duke@435 | 211 | } |
duke@435 | 212 | |
duke@435 | 213 | MemRegion reserved() const { return _reserved; } |
duke@435 | 214 | |
duke@435 | 215 | // Returns a region guaranteed to contain all the objects in the |
duke@435 | 216 | // generation. |
duke@435 | 217 | virtual MemRegion used_region() const { return _reserved; } |
duke@435 | 218 | |
duke@435 | 219 | MemRegion prev_used_region() const { return _prev_used_region; } |
duke@435 | 220 | virtual void save_used_region() { _prev_used_region = used_region(); } |
duke@435 | 221 | |
stefank@3335 | 222 | // Returns "TRUE" iff "p" points into the committed areas in the generation. |
duke@435 | 223 | // For some kinds of generations, this may be an expensive operation. |
duke@435 | 224 | // To avoid performance problems stemming from its inadvertent use in |
duke@435 | 225 | // product jvm's, we restrict its use to assertion checking or |
duke@435 | 226 | // verification only. |
duke@435 | 227 | virtual bool is_in(const void* p) const; |
duke@435 | 228 | |
duke@435 | 229 | /* Returns "TRUE" iff "p" points into the reserved area of the generation. */ |
duke@435 | 230 | bool is_in_reserved(const void* p) const { |
duke@435 | 231 | return _reserved.contains(p); |
duke@435 | 232 | } |
duke@435 | 233 | |
duke@435 | 234 | // Check that the generation kind is DefNewGeneration or a sub |
duke@435 | 235 | // class of DefNewGeneration and return a DefNewGeneration* |
duke@435 | 236 | DefNewGeneration* as_DefNewGeneration(); |
duke@435 | 237 | |
duke@435 | 238 | // If some space in the generation contains the given "addr", return a |
duke@435 | 239 | // pointer to that space, else return "NULL". |
duke@435 | 240 | virtual Space* space_containing(const void* addr) const; |
duke@435 | 241 | |
duke@435 | 242 | // Iteration - do not use for time critical operations |
duke@435 | 243 | virtual void space_iterate(SpaceClosure* blk, bool usedOnly = false) = 0; |
duke@435 | 244 | |
duke@435 | 245 | // Returns the first space, if any, in the generation that can participate |
duke@435 | 246 | // in compaction, or else "NULL". |
duke@435 | 247 | virtual CompactibleSpace* first_compaction_space() const = 0; |
duke@435 | 248 | |
duke@435 | 249 | // Returns "true" iff this generation should be used to allocate an |
duke@435 | 250 | // object of the given size. Young generations might |
duke@435 | 251 | // wish to exclude very large objects, for example, since, if allocated |
duke@435 | 252 | // often, they would greatly increase the frequency of young-gen |
duke@435 | 253 | // collection. |
duke@435 | 254 | virtual bool should_allocate(size_t word_size, bool is_tlab) { |
duke@435 | 255 | bool result = false; |
duke@435 | 256 | size_t overflow_limit = (size_t)1 << (BitsPerSize_t - LogHeapWordSize); |
duke@435 | 257 | if (!is_tlab || supports_tlab_allocation()) { |
duke@435 | 258 | result = (word_size > 0) && (word_size < overflow_limit); |
duke@435 | 259 | } |
duke@435 | 260 | return result; |
duke@435 | 261 | } |
duke@435 | 262 | |
duke@435 | 263 | // Allocate and returns a block of the requested size, or returns "NULL". |
duke@435 | 264 | // Assumes the caller has done any necessary locking. |
duke@435 | 265 | virtual HeapWord* allocate(size_t word_size, bool is_tlab) = 0; |
duke@435 | 266 | |
duke@435 | 267 | // Like "allocate", but performs any necessary locking internally. |
duke@435 | 268 | virtual HeapWord* par_allocate(size_t word_size, bool is_tlab) = 0; |
duke@435 | 269 | |
duke@435 | 270 | // A 'younger' gen has reached an allocation limit, and uses this to notify |
duke@435 | 271 | // the next older gen. The return value is a new limit, or NULL if none. The |
duke@435 | 272 | // caller must do the necessary locking. |
duke@435 | 273 | virtual HeapWord* allocation_limit_reached(Space* space, HeapWord* top, |
duke@435 | 274 | size_t word_size) { |
duke@435 | 275 | return NULL; |
duke@435 | 276 | } |
duke@435 | 277 | |
duke@435 | 278 | // Some generation may offer a region for shared, contiguous allocation, |
duke@435 | 279 | // via inlined code (by exporting the address of the top and end fields |
duke@435 | 280 | // defining the extent of the contiguous allocation region.) |
duke@435 | 281 | |
duke@435 | 282 | // This function returns "true" iff the heap supports this kind of |
duke@435 | 283 | // allocation. (More precisely, this means the style of allocation that |
duke@435 | 284 | // increments *top_addr()" with a CAS.) (Default is "no".) |
duke@435 | 285 | // A generation that supports this allocation style must use lock-free |
duke@435 | 286 | // allocation for *all* allocation, since there are times when lock free |
duke@435 | 287 | // allocation will be concurrent with plain "allocate" calls. |
duke@435 | 288 | virtual bool supports_inline_contig_alloc() const { return false; } |
duke@435 | 289 | |
duke@435 | 290 | // These functions return the addresses of the fields that define the |
duke@435 | 291 | // boundaries of the contiguous allocation area. (These fields should be |
duke@435 | 292 | // physicall near to one another.) |
duke@435 | 293 | virtual HeapWord** top_addr() const { return NULL; } |
duke@435 | 294 | virtual HeapWord** end_addr() const { return NULL; } |
duke@435 | 295 | |
duke@435 | 296 | // Thread-local allocation buffers |
duke@435 | 297 | virtual bool supports_tlab_allocation() const { return false; } |
duke@435 | 298 | virtual size_t tlab_capacity() const { |
duke@435 | 299 | guarantee(false, "Generation doesn't support thread local allocation buffers"); |
duke@435 | 300 | return 0; |
duke@435 | 301 | } |
duke@435 | 302 | virtual size_t unsafe_max_tlab_alloc() const { |
duke@435 | 303 | guarantee(false, "Generation doesn't support thread local allocation buffers"); |
duke@435 | 304 | return 0; |
duke@435 | 305 | } |
duke@435 | 306 | |
duke@435 | 307 | // "obj" is the address of an object in a younger generation. Allocate space |
duke@435 | 308 | // for "obj" in the current (or some higher) generation, and copy "obj" into |
duke@435 | 309 | // the newly allocated space, if possible, returning the result (or NULL if |
duke@435 | 310 | // the allocation failed). |
duke@435 | 311 | // |
duke@435 | 312 | // The "obj_size" argument is just obj->size(), passed along so the caller can |
duke@435 | 313 | // avoid repeating the virtual call to retrieve it. |
coleenp@548 | 314 | virtual oop promote(oop obj, size_t obj_size); |
duke@435 | 315 | |
duke@435 | 316 | // Thread "thread_num" (0 <= i < ParalleGCThreads) wants to promote |
duke@435 | 317 | // object "obj", whose original mark word was "m", and whose size is |
duke@435 | 318 | // "word_sz". If possible, allocate space for "obj", copy obj into it |
duke@435 | 319 | // (taking care to copy "m" into the mark word when done, since the mark |
duke@435 | 320 | // word of "obj" may have been overwritten with a forwarding pointer, and |
duke@435 | 321 | // also taking care to copy the klass pointer *last*. Returns the new |
duke@435 | 322 | // object if successful, or else NULL. |
duke@435 | 323 | virtual oop par_promote(int thread_num, |
duke@435 | 324 | oop obj, markOop m, size_t word_sz); |
duke@435 | 325 | |
duke@435 | 326 | // Undo, if possible, the most recent par_promote_alloc allocation by |
duke@435 | 327 | // "thread_num" ("obj", of "word_sz"). |
duke@435 | 328 | virtual void par_promote_alloc_undo(int thread_num, |
duke@435 | 329 | HeapWord* obj, size_t word_sz); |
duke@435 | 330 | |
duke@435 | 331 | // Informs the current generation that all par_promote_alloc's in the |
duke@435 | 332 | // collection have been completed; any supporting data structures can be |
duke@435 | 333 | // reset. Default is to do nothing. |
duke@435 | 334 | virtual void par_promote_alloc_done(int thread_num) {} |
duke@435 | 335 | |
duke@435 | 336 | // Informs the current generation that all oop_since_save_marks_iterates |
duke@435 | 337 | // performed by "thread_num" in the current collection, if any, have been |
duke@435 | 338 | // completed; any supporting data structures can be reset. Default is to |
duke@435 | 339 | // do nothing. |
duke@435 | 340 | virtual void par_oop_since_save_marks_iterate_done(int thread_num) {} |
duke@435 | 341 | |
duke@435 | 342 | // This generation will collect all younger generations |
duke@435 | 343 | // during a full collection. |
duke@435 | 344 | virtual bool full_collects_younger_generations() const { return false; } |
duke@435 | 345 | |
duke@435 | 346 | // This generation does in-place marking, meaning that mark words |
duke@435 | 347 | // are mutated during the marking phase and presumably reinitialized |
duke@435 | 348 | // to a canonical value after the GC. This is currently used by the |
duke@435 | 349 | // biased locking implementation to determine whether additional |
duke@435 | 350 | // work is required during the GC prologue and epilogue. |
duke@435 | 351 | virtual bool performs_in_place_marking() const { return true; } |
duke@435 | 352 | |
duke@435 | 353 | // Returns "true" iff collect() should subsequently be called on this |
duke@435 | 354 | // this generation. See comment below. |
duke@435 | 355 | // This is a generic implementation which can be overridden. |
duke@435 | 356 | // |
duke@435 | 357 | // Note: in the current (1.4) implementation, when genCollectedHeap's |
duke@435 | 358 | // incremental_collection_will_fail flag is set, all allocations are |
duke@435 | 359 | // slow path (the only fast-path place to allocate is DefNew, which |
duke@435 | 360 | // will be full if the flag is set). |
duke@435 | 361 | // Thus, older generations which collect younger generations should |
duke@435 | 362 | // test this flag and collect if it is set. |
duke@435 | 363 | virtual bool should_collect(bool full, |
duke@435 | 364 | size_t word_size, |
duke@435 | 365 | bool is_tlab) { |
duke@435 | 366 | return (full || should_allocate(word_size, is_tlab)); |
duke@435 | 367 | } |
duke@435 | 368 | |
ysr@2243 | 369 | // Returns true if the collection is likely to be safely |
ysr@2243 | 370 | // completed. Even if this method returns true, a collection |
ysr@2243 | 371 | // may not be guaranteed to succeed, and the system should be |
ysr@2243 | 372 | // able to safely unwind and recover from that failure, albeit |
ysr@2243 | 373 | // at some additional cost. |
ysr@2243 | 374 | virtual bool collection_attempt_is_safe() { |
ysr@2243 | 375 | guarantee(false, "Are you sure you want to call this method?"); |
ysr@2243 | 376 | return true; |
ysr@2243 | 377 | } |
ysr@2243 | 378 | |
duke@435 | 379 | // Perform a garbage collection. |
duke@435 | 380 | // If full is true attempt a full garbage collection of this generation. |
duke@435 | 381 | // Otherwise, attempting to (at least) free enough space to support an |
duke@435 | 382 | // allocation of the given "word_size". |
duke@435 | 383 | virtual void collect(bool full, |
duke@435 | 384 | bool clear_all_soft_refs, |
duke@435 | 385 | size_t word_size, |
duke@435 | 386 | bool is_tlab) = 0; |
duke@435 | 387 | |
duke@435 | 388 | // Perform a heap collection, attempting to create (at least) enough |
duke@435 | 389 | // space to support an allocation of the given "word_size". If |
duke@435 | 390 | // successful, perform the allocation and return the resulting |
duke@435 | 391 | // "oop" (initializing the allocated block). If the allocation is |
duke@435 | 392 | // still unsuccessful, return "NULL". |
duke@435 | 393 | virtual HeapWord* expand_and_allocate(size_t word_size, |
duke@435 | 394 | bool is_tlab, |
duke@435 | 395 | bool parallel = false) = 0; |
duke@435 | 396 | |
duke@435 | 397 | // Some generations may require some cleanup or preparation actions before |
duke@435 | 398 | // allowing a collection. The default is to do nothing. |
duke@435 | 399 | virtual void gc_prologue(bool full) {}; |
duke@435 | 400 | |
duke@435 | 401 | // Some generations may require some cleanup actions after a collection. |
duke@435 | 402 | // The default is to do nothing. |
duke@435 | 403 | virtual void gc_epilogue(bool full) {}; |
duke@435 | 404 | |
jmasa@698 | 405 | // Save the high water marks for the used space in a generation. |
jmasa@698 | 406 | virtual void record_spaces_top() {}; |
jmasa@698 | 407 | |
duke@435 | 408 | // Some generations may need to be "fixed-up" after some allocation |
duke@435 | 409 | // activity to make them parsable again. The default is to do nothing. |
duke@435 | 410 | virtual void ensure_parsability() {}; |
duke@435 | 411 | |
duke@435 | 412 | // Time (in ms) when we were last collected or now if a collection is |
duke@435 | 413 | // in progress. |
duke@435 | 414 | virtual jlong time_of_last_gc(jlong now) { |
johnc@3339 | 415 | // Both _time_of_last_gc and now are set using a time source |
johnc@3339 | 416 | // that guarantees monotonically non-decreasing values provided |
johnc@3339 | 417 | // the underlying platform provides such a source. So we still |
johnc@3339 | 418 | // have to guard against non-monotonicity. |
duke@435 | 419 | NOT_PRODUCT( |
duke@435 | 420 | if (now < _time_of_last_gc) { |
johnc@3339 | 421 | warning("time warp: "INT64_FORMAT" to "INT64_FORMAT, _time_of_last_gc, now); |
duke@435 | 422 | } |
duke@435 | 423 | ) |
duke@435 | 424 | return _time_of_last_gc; |
duke@435 | 425 | } |
duke@435 | 426 | |
duke@435 | 427 | virtual void update_time_of_last_gc(jlong now) { |
duke@435 | 428 | _time_of_last_gc = now; |
duke@435 | 429 | } |
duke@435 | 430 | |
duke@435 | 431 | // Generations may keep statistics about collection. This |
duke@435 | 432 | // method updates those statistics. current_level is |
duke@435 | 433 | // the level of the collection that has most recently |
duke@435 | 434 | // occurred. This allows the generation to decide what |
duke@435 | 435 | // statistics are valid to collect. For example, the |
duke@435 | 436 | // generation can decide to gather the amount of promoted data |
duke@435 | 437 | // if the collection of the younger generations has completed. |
duke@435 | 438 | GCStats* gc_stats() const { return _gc_stats; } |
duke@435 | 439 | virtual void update_gc_stats(int current_level, bool full) {} |
duke@435 | 440 | |
duke@435 | 441 | // Mark sweep support phase2 |
duke@435 | 442 | virtual void prepare_for_compaction(CompactPoint* cp); |
duke@435 | 443 | // Mark sweep support phase3 |
duke@435 | 444 | virtual void adjust_pointers(); |
duke@435 | 445 | // Mark sweep support phase4 |
duke@435 | 446 | virtual void compact(); |
duke@435 | 447 | virtual void post_compact() {ShouldNotReachHere();} |
duke@435 | 448 | |
duke@435 | 449 | // Support for CMS's rescan. In this general form we return a pointer |
duke@435 | 450 | // to an abstract object that can be used, based on specific previously |
duke@435 | 451 | // decided protocols, to exchange information between generations, |
duke@435 | 452 | // information that may be useful for speeding up certain types of |
duke@435 | 453 | // garbage collectors. A NULL value indicates to the client that |
duke@435 | 454 | // no data recording is expected by the provider. The data-recorder is |
duke@435 | 455 | // expected to be GC worker thread-local, with the worker index |
duke@435 | 456 | // indicated by "thr_num". |
duke@435 | 457 | virtual void* get_data_recorder(int thr_num) { return NULL; } |
duke@435 | 458 | |
duke@435 | 459 | // Some generations may require some cleanup actions before allowing |
duke@435 | 460 | // a verification. |
duke@435 | 461 | virtual void prepare_for_verify() {}; |
duke@435 | 462 | |
duke@435 | 463 | // Accessing "marks". |
duke@435 | 464 | |
duke@435 | 465 | // This function gives a generation a chance to note a point between |
duke@435 | 466 | // collections. For example, a contiguous generation might note the |
duke@435 | 467 | // beginning allocation point post-collection, which might allow some later |
duke@435 | 468 | // operations to be optimized. |
duke@435 | 469 | virtual void save_marks() {} |
duke@435 | 470 | |
duke@435 | 471 | // This function allows generations to initialize any "saved marks". That |
duke@435 | 472 | // is, should only be called when the generation is empty. |
duke@435 | 473 | virtual void reset_saved_marks() {} |
duke@435 | 474 | |
duke@435 | 475 | // This function is "true" iff any no allocations have occurred in the |
duke@435 | 476 | // generation since the last call to "save_marks". |
duke@435 | 477 | virtual bool no_allocs_since_save_marks() = 0; |
duke@435 | 478 | |
duke@435 | 479 | // Apply "cl->apply" to (the addresses of) all reference fields in objects |
duke@435 | 480 | // allocated in the current generation since the last call to "save_marks". |
duke@435 | 481 | // If more objects are allocated in this generation as a result of applying |
duke@435 | 482 | // the closure, iterates over reference fields in those objects as well. |
duke@435 | 483 | // Calls "save_marks" at the end of the iteration. |
duke@435 | 484 | // General signature... |
duke@435 | 485 | virtual void oop_since_save_marks_iterate_v(OopsInGenClosure* cl) = 0; |
duke@435 | 486 | // ...and specializations for de-virtualization. (The general |
duke@435 | 487 | // implemention of the _nv versions call the virtual version. |
duke@435 | 488 | // Note that the _nv suffix is not really semantically necessary, |
duke@435 | 489 | // but it avoids some not-so-useful warnings on Solaris.) |
duke@435 | 490 | #define Generation_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ |
duke@435 | 491 | virtual void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl) { \ |
duke@435 | 492 | oop_since_save_marks_iterate_v((OopsInGenClosure*)cl); \ |
duke@435 | 493 | } |
duke@435 | 494 | SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(Generation_SINCE_SAVE_MARKS_DECL) |
duke@435 | 495 | |
duke@435 | 496 | #undef Generation_SINCE_SAVE_MARKS_DECL |
duke@435 | 497 | |
duke@435 | 498 | // The "requestor" generation is performing some garbage collection |
duke@435 | 499 | // action for which it would be useful to have scratch space. If |
duke@435 | 500 | // the target is not the requestor, no gc actions will be required |
duke@435 | 501 | // of the target. The requestor promises to allocate no more than |
duke@435 | 502 | // "max_alloc_words" in the target generation (via promotion say, |
duke@435 | 503 | // if the requestor is a young generation and the target is older). |
duke@435 | 504 | // If the target generation can provide any scratch space, it adds |
duke@435 | 505 | // it to "list", leaving "list" pointing to the head of the |
duke@435 | 506 | // augmented list. The default is to offer no space. |
duke@435 | 507 | virtual void contribute_scratch(ScratchBlock*& list, Generation* requestor, |
duke@435 | 508 | size_t max_alloc_words) {} |
duke@435 | 509 | |
jmasa@698 | 510 | // Give each generation an opportunity to do clean up for any |
jmasa@698 | 511 | // contributed scratch. |
jmasa@698 | 512 | virtual void reset_scratch() {}; |
jmasa@698 | 513 | |
duke@435 | 514 | // When an older generation has been collected, and perhaps resized, |
duke@435 | 515 | // this method will be invoked on all younger generations (from older to |
duke@435 | 516 | // younger), allowing them to resize themselves as appropriate. |
duke@435 | 517 | virtual void compute_new_size() = 0; |
duke@435 | 518 | |
duke@435 | 519 | // Printing |
duke@435 | 520 | virtual const char* name() const = 0; |
duke@435 | 521 | virtual const char* short_name() const = 0; |
duke@435 | 522 | |
duke@435 | 523 | int level() const { return _level; } |
duke@435 | 524 | |
duke@435 | 525 | // Attributes |
duke@435 | 526 | |
duke@435 | 527 | // True iff the given generation may only be the youngest generation. |
duke@435 | 528 | virtual bool must_be_youngest() const = 0; |
duke@435 | 529 | // True iff the given generation may only be the oldest generation. |
duke@435 | 530 | virtual bool must_be_oldest() const = 0; |
duke@435 | 531 | |
duke@435 | 532 | // Reference Processing accessor |
duke@435 | 533 | ReferenceProcessor* const ref_processor() { return _ref_processor; } |
duke@435 | 534 | |
duke@435 | 535 | // Iteration. |
duke@435 | 536 | |
duke@435 | 537 | // Iterate over all the ref-containing fields of all objects in the |
duke@435 | 538 | // generation, calling "cl.do_oop" on each. |
coleenp@4037 | 539 | virtual void oop_iterate(ExtendedOopClosure* cl); |
duke@435 | 540 | |
duke@435 | 541 | // Same as above, restricted to the intersection of a memory region and |
duke@435 | 542 | // the generation. |
coleenp@4037 | 543 | virtual void oop_iterate(MemRegion mr, ExtendedOopClosure* cl); |
duke@435 | 544 | |
duke@435 | 545 | // Iterate over all objects in the generation, calling "cl.do_object" on |
duke@435 | 546 | // each. |
duke@435 | 547 | virtual void object_iterate(ObjectClosure* cl); |
duke@435 | 548 | |
jmasa@952 | 549 | // Iterate over all safe objects in the generation, calling "cl.do_object" on |
jmasa@952 | 550 | // each. An object is safe if its references point to other objects in |
jmasa@952 | 551 | // the heap. This defaults to object_iterate() unless overridden. |
jmasa@952 | 552 | virtual void safe_object_iterate(ObjectClosure* cl); |
jmasa@952 | 553 | |
duke@435 | 554 | // Iterate over all objects allocated in the generation since the last |
duke@435 | 555 | // collection, calling "cl.do_object" on each. The generation must have |
duke@435 | 556 | // been initialized properly to support this function, or else this call |
duke@435 | 557 | // will fail. |
duke@435 | 558 | virtual void object_iterate_since_last_GC(ObjectClosure* cl) = 0; |
duke@435 | 559 | |
duke@435 | 560 | // Apply "cl->do_oop" to (the address of) all and only all the ref fields |
duke@435 | 561 | // in the current generation that contain pointers to objects in younger |
duke@435 | 562 | // generations. Objects allocated since the last "save_marks" call are |
duke@435 | 563 | // excluded. |
duke@435 | 564 | virtual void younger_refs_iterate(OopsInGenClosure* cl) = 0; |
duke@435 | 565 | |
duke@435 | 566 | // Inform a generation that it longer contains references to objects |
duke@435 | 567 | // in any younger generation. [e.g. Because younger gens are empty, |
duke@435 | 568 | // clear the card table.] |
duke@435 | 569 | virtual void clear_remembered_set() { } |
duke@435 | 570 | |
duke@435 | 571 | // Inform a generation that some of its objects have moved. [e.g. The |
duke@435 | 572 | // generation's spaces were compacted, invalidating the card table.] |
duke@435 | 573 | virtual void invalidate_remembered_set() { } |
duke@435 | 574 | |
duke@435 | 575 | // Block abstraction. |
duke@435 | 576 | |
duke@435 | 577 | // Returns the address of the start of the "block" that contains the |
duke@435 | 578 | // address "addr". We say "blocks" instead of "object" since some heaps |
duke@435 | 579 | // may not pack objects densely; a chunk may either be an object or a |
duke@435 | 580 | // non-object. |
duke@435 | 581 | virtual HeapWord* block_start(const void* addr) const; |
duke@435 | 582 | |
duke@435 | 583 | // Requires "addr" to be the start of a chunk, and returns its size. |
duke@435 | 584 | // "addr + size" is required to be the start of a new chunk, or the end |
duke@435 | 585 | // of the active area of the heap. |
duke@435 | 586 | virtual size_t block_size(const HeapWord* addr) const ; |
duke@435 | 587 | |
duke@435 | 588 | // Requires "addr" to be the start of a block, and returns "TRUE" iff |
duke@435 | 589 | // the block is an object. |
duke@435 | 590 | virtual bool block_is_obj(const HeapWord* addr) const; |
duke@435 | 591 | |
duke@435 | 592 | |
duke@435 | 593 | // PrintGC, PrintGCDetails support |
duke@435 | 594 | void print_heap_change(size_t prev_used) const; |
duke@435 | 595 | |
duke@435 | 596 | // PrintHeapAtGC support |
duke@435 | 597 | virtual void print() const; |
duke@435 | 598 | virtual void print_on(outputStream* st) const; |
duke@435 | 599 | |
brutisso@3711 | 600 | virtual void verify() = 0; |
duke@435 | 601 | |
duke@435 | 602 | struct StatRecord { |
duke@435 | 603 | int invocations; |
duke@435 | 604 | elapsedTimer accumulated_time; |
duke@435 | 605 | StatRecord() : |
duke@435 | 606 | invocations(0), |
duke@435 | 607 | accumulated_time(elapsedTimer()) {} |
duke@435 | 608 | }; |
duke@435 | 609 | private: |
duke@435 | 610 | StatRecord _stat_record; |
duke@435 | 611 | public: |
duke@435 | 612 | StatRecord* stat_record() { return &_stat_record; } |
duke@435 | 613 | |
duke@435 | 614 | virtual void print_summary_info(); |
duke@435 | 615 | virtual void print_summary_info_on(outputStream* st); |
duke@435 | 616 | |
duke@435 | 617 | // Performance Counter support |
duke@435 | 618 | virtual void update_counters() = 0; |
duke@435 | 619 | virtual CollectorCounters* counters() { return _gc_counters; } |
duke@435 | 620 | }; |
duke@435 | 621 | |
duke@435 | 622 | // Class CardGeneration is a generation that is covered by a card table, |
duke@435 | 623 | // and uses a card-size block-offset array to implement block_start. |
duke@435 | 624 | |
duke@435 | 625 | // class BlockOffsetArray; |
duke@435 | 626 | // class BlockOffsetArrayContigSpace; |
duke@435 | 627 | class BlockOffsetSharedArray; |
duke@435 | 628 | |
duke@435 | 629 | class CardGeneration: public Generation { |
duke@435 | 630 | friend class VMStructs; |
duke@435 | 631 | protected: |
duke@435 | 632 | // This is shared with other generations. |
duke@435 | 633 | GenRemSet* _rs; |
duke@435 | 634 | // This is local to this generation. |
duke@435 | 635 | BlockOffsetSharedArray* _bts; |
duke@435 | 636 | |
jmasa@4900 | 637 | // current shrinking effect: this damps shrinking when the heap gets empty. |
jmasa@4900 | 638 | size_t _shrink_factor; |
jmasa@4900 | 639 | |
jmasa@4900 | 640 | size_t _min_heap_delta_bytes; // Minimum amount to expand. |
jmasa@4900 | 641 | |
jmasa@4900 | 642 | // Some statistics from before gc started. |
jmasa@4900 | 643 | // These are gathered in the gc_prologue (and should_collect) |
jmasa@4900 | 644 | // to control growing/shrinking policy in spite of promotions. |
jmasa@4900 | 645 | size_t _capacity_at_prologue; |
jmasa@4900 | 646 | size_t _used_at_prologue; |
jmasa@4900 | 647 | |
duke@435 | 648 | CardGeneration(ReservedSpace rs, size_t initial_byte_size, int level, |
duke@435 | 649 | GenRemSet* remset); |
duke@435 | 650 | |
duke@435 | 651 | public: |
duke@435 | 652 | |
jmasa@706 | 653 | // Attempt to expand the generation by "bytes". Expand by at a |
jmasa@706 | 654 | // minimum "expand_bytes". Return true if some amount (not |
jmasa@706 | 655 | // necessarily the full "bytes") was done. |
jmasa@706 | 656 | virtual bool expand(size_t bytes, size_t expand_bytes); |
jmasa@706 | 657 | |
jmasa@4900 | 658 | // Shrink generation with specified size (returns false if unable to shrink) |
jmasa@4900 | 659 | virtual void shrink(size_t bytes) = 0; |
jmasa@4900 | 660 | |
jmasa@4900 | 661 | virtual void compute_new_size(); |
jmasa@4900 | 662 | |
duke@435 | 663 | virtual void clear_remembered_set(); |
duke@435 | 664 | |
duke@435 | 665 | virtual void invalidate_remembered_set(); |
duke@435 | 666 | |
duke@435 | 667 | virtual void prepare_for_verify(); |
jmasa@706 | 668 | |
jmasa@706 | 669 | // Grow generation with specified size (returns false if unable to grow) |
jmasa@706 | 670 | virtual bool grow_by(size_t bytes) = 0; |
jmasa@706 | 671 | // Grow generation to reserved size. |
jmasa@706 | 672 | virtual bool grow_to_reserved() = 0; |
duke@435 | 673 | }; |
duke@435 | 674 | |
duke@435 | 675 | // OneContigSpaceCardGeneration models a heap of old objects contained in a single |
duke@435 | 676 | // contiguous space. |
duke@435 | 677 | // |
duke@435 | 678 | // Garbage collection is performed using mark-compact. |
duke@435 | 679 | |
duke@435 | 680 | class OneContigSpaceCardGeneration: public CardGeneration { |
duke@435 | 681 | friend class VMStructs; |
duke@435 | 682 | // Abstractly, this is a subtype that gets access to protected fields. |
duke@435 | 683 | friend class VM_PopulateDumpSharedSpace; |
duke@435 | 684 | |
duke@435 | 685 | protected: |
duke@435 | 686 | ContiguousSpace* _the_space; // actual space holding objects |
duke@435 | 687 | WaterMark _last_gc; // watermark between objects allocated before |
duke@435 | 688 | // and after last GC. |
duke@435 | 689 | |
duke@435 | 690 | // Grow generation with specified size (returns false if unable to grow) |
jmasa@706 | 691 | virtual bool grow_by(size_t bytes); |
duke@435 | 692 | // Grow generation to reserved size. |
jmasa@706 | 693 | virtual bool grow_to_reserved(); |
duke@435 | 694 | // Shrink generation with specified size (returns false if unable to shrink) |
duke@435 | 695 | void shrink_by(size_t bytes); |
duke@435 | 696 | |
duke@435 | 697 | // Allocation failure |
jmasa@706 | 698 | virtual bool expand(size_t bytes, size_t expand_bytes); |
duke@435 | 699 | void shrink(size_t bytes); |
duke@435 | 700 | |
duke@435 | 701 | // Accessing spaces |
duke@435 | 702 | ContiguousSpace* the_space() const { return _the_space; } |
duke@435 | 703 | |
duke@435 | 704 | public: |
duke@435 | 705 | OneContigSpaceCardGeneration(ReservedSpace rs, size_t initial_byte_size, |
duke@435 | 706 | int level, GenRemSet* remset, |
duke@435 | 707 | ContiguousSpace* space) : |
duke@435 | 708 | CardGeneration(rs, initial_byte_size, level, remset), |
jmasa@4900 | 709 | _the_space(space) |
duke@435 | 710 | {} |
duke@435 | 711 | |
duke@435 | 712 | inline bool is_in(const void* p) const; |
duke@435 | 713 | |
duke@435 | 714 | // Space enquiries |
duke@435 | 715 | size_t capacity() const; |
duke@435 | 716 | size_t used() const; |
duke@435 | 717 | size_t free() const; |
duke@435 | 718 | |
duke@435 | 719 | MemRegion used_region() const; |
duke@435 | 720 | |
duke@435 | 721 | size_t unsafe_max_alloc_nogc() const; |
duke@435 | 722 | size_t contiguous_available() const; |
duke@435 | 723 | |
duke@435 | 724 | // Iteration |
duke@435 | 725 | void object_iterate(ObjectClosure* blk); |
duke@435 | 726 | void space_iterate(SpaceClosure* blk, bool usedOnly = false); |
duke@435 | 727 | void object_iterate_since_last_GC(ObjectClosure* cl); |
duke@435 | 728 | |
duke@435 | 729 | void younger_refs_iterate(OopsInGenClosure* blk); |
duke@435 | 730 | |
duke@435 | 731 | inline CompactibleSpace* first_compaction_space() const; |
duke@435 | 732 | |
duke@435 | 733 | virtual inline HeapWord* allocate(size_t word_size, bool is_tlab); |
duke@435 | 734 | virtual inline HeapWord* par_allocate(size_t word_size, bool is_tlab); |
duke@435 | 735 | |
duke@435 | 736 | // Accessing marks |
duke@435 | 737 | inline WaterMark top_mark(); |
duke@435 | 738 | inline WaterMark bottom_mark(); |
duke@435 | 739 | |
duke@435 | 740 | #define OneContig_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ |
duke@435 | 741 | void oop_since_save_marks_iterate##nv_suffix(OopClosureType* cl); |
duke@435 | 742 | OneContig_SINCE_SAVE_MARKS_DECL(OopsInGenClosure,_v) |
duke@435 | 743 | SPECIALIZED_SINCE_SAVE_MARKS_CLOSURES(OneContig_SINCE_SAVE_MARKS_DECL) |
duke@435 | 744 | |
duke@435 | 745 | void save_marks(); |
duke@435 | 746 | void reset_saved_marks(); |
duke@435 | 747 | bool no_allocs_since_save_marks(); |
duke@435 | 748 | |
duke@435 | 749 | inline size_t block_size(const HeapWord* addr) const; |
duke@435 | 750 | |
duke@435 | 751 | inline bool block_is_obj(const HeapWord* addr) const; |
duke@435 | 752 | |
duke@435 | 753 | virtual void collect(bool full, |
duke@435 | 754 | bool clear_all_soft_refs, |
duke@435 | 755 | size_t size, |
duke@435 | 756 | bool is_tlab); |
duke@435 | 757 | HeapWord* expand_and_allocate(size_t size, |
duke@435 | 758 | bool is_tlab, |
duke@435 | 759 | bool parallel = false); |
duke@435 | 760 | |
duke@435 | 761 | virtual void prepare_for_verify(); |
duke@435 | 762 | |
duke@435 | 763 | virtual void gc_epilogue(bool full); |
duke@435 | 764 | |
jmasa@698 | 765 | virtual void record_spaces_top(); |
jmasa@698 | 766 | |
brutisso@3711 | 767 | virtual void verify(); |
duke@435 | 768 | virtual void print_on(outputStream* st) const; |
duke@435 | 769 | }; |
stefank@2314 | 770 | |
stefank@2314 | 771 | #endif // SHARE_VM_MEMORY_GENERATION_HPP |