Mercurial > hg > truffle
annotate src/share/vm/memory/space.hpp @ 113:ba764ed4b6f2
6420645: Create a vm that uses compressed oops for up to 32gb heapsizes
Summary: Compressed oops in instances, arrays, and headers. Code contributors are coleenp, phh, never, swamyv
Reviewed-by: jmasa, kamg, acorn, tbell, kvn, rasbold
| author | coleenp |
|---|---|
| date | Sun, 13 Apr 2008 17:43:42 -0400 |
| parents | a61af66fc99e |
| children | d1605aabd0a1 12eea04c8b06 37f87013dfd8 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 2 * Copyright 1997-2007 Sun Microsystems, Inc. All Rights Reserved. | |
| 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. | |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
| 19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
| 20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
| 21 * have any questions. | |
| 22 * | |
| 23 */ | |
| 24 | |
| 25 // A space is an abstraction for the "storage units" backing | |
| 26 // up the generation abstraction. It includes specific | |
| 27 // implementations for keeping track of free and used space, | |
| 28 // for iterating over objects and free blocks, etc. | |
| 29 | |
| 30 // Here's the Space hierarchy: | |
| 31 // | |
| 32 // - Space -- an asbtract base class describing a heap area | |
| 33 // - CompactibleSpace -- a space supporting compaction | |
| 34 // - CompactibleFreeListSpace -- (used for CMS generation) | |
| 35 // - ContiguousSpace -- a compactible space in which all free space | |
| 36 // is contiguous | |
| 37 // - EdenSpace -- contiguous space used as nursery | |
| 38 // - ConcEdenSpace -- contiguous space with a 'soft end safe' allocation | |
| 39 // - OffsetTableContigSpace -- contiguous space with a block offset array | |
| 40 // that allows "fast" block_start calls | |
| 41 // - TenuredSpace -- (used for TenuredGeneration) | |
| 42 // - ContigPermSpace -- an offset table contiguous space for perm gen | |
| 43 | |
| 44 // Forward decls. | |
| 45 class Space; | |
| 46 class BlockOffsetArray; | |
| 47 class BlockOffsetArrayContigSpace; | |
| 48 class Generation; | |
| 49 class CompactibleSpace; | |
| 50 class BlockOffsetTable; | |
| 51 class GenRemSet; | |
| 52 class CardTableRS; | |
| 53 class DirtyCardToOopClosure; | |
| 54 | |
| 55 // An oop closure that is circumscribed by a filtering memory region. | |
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56 class SpaceMemRegionOopsIterClosure: public OopClosure { |
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57 private: |
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58 OopClosure* _cl; |
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59 MemRegion _mr; |
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60 protected: |
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61 template <class T> void do_oop_work(T* p) { |
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62 if (_mr.contains(p)) { |
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63 _cl->do_oop(p); |
| 0 | 64 } |
| 65 } | |
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66 public: |
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67 SpaceMemRegionOopsIterClosure(OopClosure* cl, MemRegion mr): |
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68 _cl(cl), _mr(mr) {} |
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69 virtual void do_oop(oop* p); |
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70 virtual void do_oop(narrowOop* p); |
| 0 | 71 }; |
| 72 | |
| 73 // A Space describes a heap area. Class Space is an abstract | |
| 74 // base class. | |
| 75 // | |
| 76 // Space supports allocation, size computation and GC support is provided. | |
| 77 // | |
| 78 // Invariant: bottom() and end() are on page_size boundaries and | |
| 79 // bottom() <= top() <= end() | |
| 80 // top() is inclusive and end() is exclusive. | |
| 81 | |
| 82 class Space: public CHeapObj { | |
| 83 friend class VMStructs; | |
| 84 protected: | |
| 85 HeapWord* _bottom; | |
| 86 HeapWord* _end; | |
| 87 | |
| 88 // Used in support of save_marks() | |
| 89 HeapWord* _saved_mark_word; | |
| 90 | |
| 91 MemRegionClosure* _preconsumptionDirtyCardClosure; | |
| 92 | |
| 93 // A sequential tasks done structure. This supports | |
| 94 // parallel GC, where we have threads dynamically | |
| 95 // claiming sub-tasks from a larger parallel task. | |
| 96 SequentialSubTasksDone _par_seq_tasks; | |
| 97 | |
| 98 Space(): | |
| 99 _bottom(NULL), _end(NULL), _preconsumptionDirtyCardClosure(NULL) { } | |
| 100 | |
| 101 public: | |
| 102 // Accessors | |
| 103 HeapWord* bottom() const { return _bottom; } | |
| 104 HeapWord* end() const { return _end; } | |
| 105 virtual void set_bottom(HeapWord* value) { _bottom = value; } | |
| 106 virtual void set_end(HeapWord* value) { _end = value; } | |
| 107 | |
| 108 HeapWord* saved_mark_word() const { return _saved_mark_word; } | |
| 109 void set_saved_mark_word(HeapWord* p) { _saved_mark_word = p; } | |
| 110 | |
| 111 MemRegionClosure* preconsumptionDirtyCardClosure() const { | |
| 112 return _preconsumptionDirtyCardClosure; | |
| 113 } | |
| 114 void setPreconsumptionDirtyCardClosure(MemRegionClosure* cl) { | |
| 115 _preconsumptionDirtyCardClosure = cl; | |
| 116 } | |
| 117 | |
| 118 // Returns a subregion of the space containing all the objects in | |
| 119 // the space. | |
| 120 virtual MemRegion used_region() const { return MemRegion(bottom(), end()); } | |
| 121 | |
| 122 // Returns a region that is guaranteed to contain (at least) all objects | |
| 123 // allocated at the time of the last call to "save_marks". If the space | |
| 124 // initializes its DirtyCardToOopClosure's specifying the "contig" option | |
| 125 // (that is, if the space is contiguous), then this region must contain only | |
| 126 // such objects: the memregion will be from the bottom of the region to the | |
| 127 // saved mark. Otherwise, the "obj_allocated_since_save_marks" method of | |
| 128 // the space must distiguish between objects in the region allocated before | |
| 129 // and after the call to save marks. | |
| 130 virtual MemRegion used_region_at_save_marks() const { | |
| 131 return MemRegion(bottom(), saved_mark_word()); | |
| 132 } | |
| 133 | |
| 134 // Initialization | |
| 135 virtual void initialize(MemRegion mr, bool clear_space); | |
| 136 virtual void clear(); | |
| 137 | |
| 138 // For detecting GC bugs. Should only be called at GC boundaries, since | |
| 139 // some unused space may be used as scratch space during GC's. | |
| 140 // Default implementation does nothing. We also call this when expanding | |
| 141 // a space to satisfy an allocation request. See bug #4668531 | |
| 142 virtual void mangle_unused_area() {} | |
| 143 virtual void mangle_region(MemRegion mr) {} | |
| 144 | |
| 145 // Testers | |
| 146 bool is_empty() const { return used() == 0; } | |
| 147 bool not_empty() const { return used() > 0; } | |
| 148 | |
| 149 // Returns true iff the given the space contains the | |
| 150 // given address as part of an allocated object. For | |
| 151 // ceratin kinds of spaces, this might be a potentially | |
| 152 // expensive operation. To prevent performance problems | |
| 153 // on account of its inadvertent use in product jvm's, | |
| 154 // we restrict its use to assertion checks only. | |
| 155 virtual bool is_in(const void* p) const; | |
| 156 | |
| 157 // Returns true iff the given reserved memory of the space contains the | |
| 158 // given address. | |
| 159 bool is_in_reserved(const void* p) const { return _bottom <= p && p < _end; } | |
| 160 | |
| 161 // Returns true iff the given block is not allocated. | |
| 162 virtual bool is_free_block(const HeapWord* p) const = 0; | |
| 163 | |
| 164 // Test whether p is double-aligned | |
| 165 static bool is_aligned(void* p) { | |
| 166 return ((intptr_t)p & (sizeof(double)-1)) == 0; | |
| 167 } | |
| 168 | |
| 169 // Size computations. Sizes are in bytes. | |
| 170 size_t capacity() const { return byte_size(bottom(), end()); } | |
| 171 virtual size_t used() const = 0; | |
| 172 virtual size_t free() const = 0; | |
| 173 | |
| 174 // Iterate over all the ref-containing fields of all objects in the | |
| 175 // space, calling "cl.do_oop" on each. Fields in objects allocated by | |
| 176 // applications of the closure are not included in the iteration. | |
| 177 virtual void oop_iterate(OopClosure* cl); | |
| 178 | |
| 179 // Same as above, restricted to the intersection of a memory region and | |
| 180 // the space. Fields in objects allocated by applications of the closure | |
| 181 // are not included in the iteration. | |
| 182 virtual void oop_iterate(MemRegion mr, OopClosure* cl) = 0; | |
| 183 | |
| 184 // Iterate over all objects in the space, calling "cl.do_object" on | |
| 185 // each. Objects allocated by applications of the closure are not | |
| 186 // included in the iteration. | |
| 187 virtual void object_iterate(ObjectClosure* blk) = 0; | |
| 188 | |
| 189 // Iterate over all objects that intersect with mr, calling "cl->do_object" | |
| 190 // on each. There is an exception to this: if this closure has already | |
| 191 // been invoked on an object, it may skip such objects in some cases. This is | |
| 192 // Most likely to happen in an "upwards" (ascending address) iteration of | |
| 193 // MemRegions. | |
| 194 virtual void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl); | |
| 195 | |
| 196 // Iterate over as many initialized objects in the space as possible, | |
| 197 // calling "cl.do_object_careful" on each. Return NULL if all objects | |
| 198 // in the space (at the start of the iteration) were iterated over. | |
| 199 // Return an address indicating the extent of the iteration in the | |
| 200 // event that the iteration had to return because of finding an | |
| 201 // uninitialized object in the space, or if the closure "cl" | |
| 202 // signalled early termination. | |
| 203 virtual HeapWord* object_iterate_careful(ObjectClosureCareful* cl); | |
| 204 virtual HeapWord* object_iterate_careful_m(MemRegion mr, | |
| 205 ObjectClosureCareful* cl); | |
| 206 | |
| 207 // Create and return a new dirty card to oop closure. Can be | |
| 208 // overriden to return the appropriate type of closure | |
| 209 // depending on the type of space in which the closure will | |
| 210 // operate. ResourceArea allocated. | |
| 211 virtual DirtyCardToOopClosure* new_dcto_cl(OopClosure* cl, | |
| 212 CardTableModRefBS::PrecisionStyle precision, | |
| 213 HeapWord* boundary = NULL); | |
| 214 | |
| 215 // If "p" is in the space, returns the address of the start of the | |
| 216 // "block" that contains "p". We say "block" instead of "object" since | |
| 217 // some heaps may not pack objects densely; a chunk may either be an | |
| 218 // object or a non-object. If "p" is not in the space, return NULL. | |
| 219 virtual HeapWord* block_start(const void* p) const = 0; | |
| 220 | |
| 221 // Requires "addr" to be the start of a chunk, and returns its size. | |
| 222 // "addr + size" is required to be the start of a new chunk, or the end | |
| 223 // of the active area of the heap. | |
| 224 virtual size_t block_size(const HeapWord* addr) const = 0; | |
| 225 | |
| 226 // Requires "addr" to be the start of a block, and returns "TRUE" iff | |
| 227 // the block is an object. | |
| 228 virtual bool block_is_obj(const HeapWord* addr) const = 0; | |
| 229 | |
| 230 // Requires "addr" to be the start of a block, and returns "TRUE" iff | |
| 231 // the block is an object and the object is alive. | |
| 232 virtual bool obj_is_alive(const HeapWord* addr) const; | |
| 233 | |
| 234 // Allocation (return NULL if full). Assumes the caller has established | |
| 235 // mutually exclusive access to the space. | |
| 236 virtual HeapWord* allocate(size_t word_size) = 0; | |
| 237 | |
| 238 // Allocation (return NULL if full). Enforces mutual exclusion internally. | |
| 239 virtual HeapWord* par_allocate(size_t word_size) = 0; | |
| 240 | |
| 241 // Returns true if this object has been allocated since a | |
| 242 // generation's "save_marks" call. | |
| 243 virtual bool obj_allocated_since_save_marks(const oop obj) const = 0; | |
| 244 | |
| 245 // Mark-sweep-compact support: all spaces can update pointers to objects | |
| 246 // moving as a part of compaction. | |
| 247 virtual void adjust_pointers(); | |
| 248 | |
| 249 // PrintHeapAtGC support | |
| 250 virtual void print() const; | |
| 251 virtual void print_on(outputStream* st) const; | |
| 252 virtual void print_short() const; | |
| 253 virtual void print_short_on(outputStream* st) const; | |
| 254 | |
| 255 | |
| 256 // Accessor for parallel sequential tasks. | |
| 257 SequentialSubTasksDone* par_seq_tasks() { return &_par_seq_tasks; } | |
| 258 | |
| 259 // IF "this" is a ContiguousSpace, return it, else return NULL. | |
| 260 virtual ContiguousSpace* toContiguousSpace() { | |
| 261 return NULL; | |
| 262 } | |
| 263 | |
| 264 // Debugging | |
| 265 virtual void verify(bool allow_dirty) const = 0; | |
| 266 }; | |
| 267 | |
| 268 // A MemRegionClosure (ResourceObj) whose "do_MemRegion" function applies an | |
| 269 // OopClosure to (the addresses of) all the ref-containing fields that could | |
| 270 // be modified by virtue of the given MemRegion being dirty. (Note that | |
| 271 // because of the imprecise nature of the write barrier, this may iterate | |
| 272 // over oops beyond the region.) | |
| 273 // This base type for dirty card to oop closures handles memory regions | |
| 274 // in non-contiguous spaces with no boundaries, and should be sub-classed | |
| 275 // to support other space types. See ContiguousDCTOC for a sub-class | |
| 276 // that works with ContiguousSpaces. | |
| 277 | |
| 278 class DirtyCardToOopClosure: public MemRegionClosureRO { | |
| 279 protected: | |
| 280 OopClosure* _cl; | |
| 281 Space* _sp; | |
| 282 CardTableModRefBS::PrecisionStyle _precision; | |
| 283 HeapWord* _boundary; // If non-NULL, process only non-NULL oops | |
| 284 // pointing below boundary. | |
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285 HeapWord* _min_done; // ObjHeadPreciseArray precision requires |
| 0 | 286 // a downwards traversal; this is the |
| 287 // lowest location already done (or, | |
| 288 // alternatively, the lowest address that | |
| 289 // shouldn't be done again. NULL means infinity.) | |
| 290 NOT_PRODUCT(HeapWord* _last_bottom;) | |
| 291 | |
| 292 // Get the actual top of the area on which the closure will | |
| 293 // operate, given where the top is assumed to be (the end of the | |
| 294 // memory region passed to do_MemRegion) and where the object | |
| 295 // at the top is assumed to start. For example, an object may | |
| 296 // start at the top but actually extend past the assumed top, | |
| 297 // in which case the top becomes the end of the object. | |
| 298 virtual HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj); | |
| 299 | |
| 300 // Walk the given memory region from bottom to (actual) top | |
| 301 // looking for objects and applying the oop closure (_cl) to | |
| 302 // them. The base implementation of this treats the area as | |
| 303 // blocks, where a block may or may not be an object. Sub- | |
| 304 // classes should override this to provide more accurate | |
| 305 // or possibly more efficient walking. | |
| 306 virtual void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top); | |
| 307 | |
| 308 public: | |
| 309 DirtyCardToOopClosure(Space* sp, OopClosure* cl, | |
| 310 CardTableModRefBS::PrecisionStyle precision, | |
| 311 HeapWord* boundary) : | |
| 312 _sp(sp), _cl(cl), _precision(precision), _boundary(boundary), | |
| 313 _min_done(NULL) { | |
| 314 NOT_PRODUCT(_last_bottom = NULL;) | |
| 315 } | |
| 316 | |
| 317 void do_MemRegion(MemRegion mr); | |
| 318 | |
| 319 void set_min_done(HeapWord* min_done) { | |
| 320 _min_done = min_done; | |
| 321 } | |
| 322 #ifndef PRODUCT | |
| 323 void set_last_bottom(HeapWord* last_bottom) { | |
| 324 _last_bottom = last_bottom; | |
| 325 } | |
| 326 #endif | |
| 327 }; | |
| 328 | |
| 329 // A structure to represent a point at which objects are being copied | |
| 330 // during compaction. | |
| 331 class CompactPoint : public StackObj { | |
| 332 public: | |
| 333 Generation* gen; | |
| 334 CompactibleSpace* space; | |
| 335 HeapWord* threshold; | |
| 336 CompactPoint(Generation* _gen, CompactibleSpace* _space, | |
| 337 HeapWord* _threshold) : | |
| 338 gen(_gen), space(_space), threshold(_threshold) {} | |
| 339 }; | |
| 340 | |
| 341 | |
| 342 // A space that supports compaction operations. This is usually, but not | |
| 343 // necessarily, a space that is normally contiguous. But, for example, a | |
| 344 // free-list-based space whose normal collection is a mark-sweep without | |
| 345 // compaction could still support compaction in full GC's. | |
| 346 | |
| 347 class CompactibleSpace: public Space { | |
| 348 friend class VMStructs; | |
| 349 friend class CompactibleFreeListSpace; | |
| 350 friend class CompactingPermGenGen; | |
| 351 friend class CMSPermGenGen; | |
| 352 private: | |
| 353 HeapWord* _compaction_top; | |
| 354 CompactibleSpace* _next_compaction_space; | |
| 355 | |
| 356 public: | |
| 357 virtual void initialize(MemRegion mr, bool clear_space); | |
| 358 | |
| 359 // Used temporarily during a compaction phase to hold the value | |
| 360 // top should have when compaction is complete. | |
| 361 HeapWord* compaction_top() const { return _compaction_top; } | |
| 362 | |
| 363 void set_compaction_top(HeapWord* value) { | |
| 364 assert(value == NULL || (value >= bottom() && value <= end()), | |
| 365 "should point inside space"); | |
| 366 _compaction_top = value; | |
| 367 } | |
| 368 | |
| 369 // Perform operations on the space needed after a compaction | |
| 370 // has been performed. | |
| 371 virtual void reset_after_compaction() {} | |
| 372 | |
| 373 // Returns the next space (in the current generation) to be compacted in | |
| 374 // the global compaction order. Also is used to select the next | |
| 375 // space into which to compact. | |
| 376 | |
| 377 virtual CompactibleSpace* next_compaction_space() const { | |
| 378 return _next_compaction_space; | |
| 379 } | |
| 380 | |
| 381 void set_next_compaction_space(CompactibleSpace* csp) { | |
| 382 _next_compaction_space = csp; | |
| 383 } | |
| 384 | |
| 385 // MarkSweep support phase2 | |
| 386 | |
| 387 // Start the process of compaction of the current space: compute | |
| 388 // post-compaction addresses, and insert forwarding pointers. The fields | |
| 389 // "cp->gen" and "cp->compaction_space" are the generation and space into | |
| 390 // which we are currently compacting. This call updates "cp" as necessary, | |
| 391 // and leaves the "compaction_top" of the final value of | |
| 392 // "cp->compaction_space" up-to-date. Offset tables may be updated in | |
| 393 // this phase as if the final copy had occurred; if so, "cp->threshold" | |
| 394 // indicates when the next such action should be taken. | |
| 395 virtual void prepare_for_compaction(CompactPoint* cp); | |
| 396 // MarkSweep support phase3 | |
| 397 virtual void adjust_pointers(); | |
| 398 // MarkSweep support phase4 | |
| 399 virtual void compact(); | |
| 400 | |
| 401 // The maximum percentage of objects that can be dead in the compacted | |
| 402 // live part of a compacted space ("deadwood" support.) | |
| 403 virtual int allowed_dead_ratio() const { return 0; }; | |
| 404 | |
| 405 // Some contiguous spaces may maintain some data structures that should | |
| 406 // be updated whenever an allocation crosses a boundary. This function | |
| 407 // returns the first such boundary. | |
| 408 // (The default implementation returns the end of the space, so the | |
| 409 // boundary is never crossed.) | |
| 410 virtual HeapWord* initialize_threshold() { return end(); } | |
| 411 | |
| 412 // "q" is an object of the given "size" that should be forwarded; | |
| 413 // "cp" names the generation ("gen") and containing "this" (which must | |
| 414 // also equal "cp->space"). "compact_top" is where in "this" the | |
| 415 // next object should be forwarded to. If there is room in "this" for | |
| 416 // the object, insert an appropriate forwarding pointer in "q". | |
| 417 // If not, go to the next compaction space (there must | |
| 418 // be one, since compaction must succeed -- we go to the first space of | |
| 419 // the previous generation if necessary, updating "cp"), reset compact_top | |
| 420 // and then forward. In either case, returns the new value of "compact_top". | |
| 421 // If the forwarding crosses "cp->threshold", invokes the "cross_threhold" | |
| 422 // function of the then-current compaction space, and updates "cp->threshold | |
| 423 // accordingly". | |
| 424 virtual HeapWord* forward(oop q, size_t size, CompactPoint* cp, | |
| 425 HeapWord* compact_top); | |
| 426 | |
| 427 // Return a size with adjusments as required of the space. | |
| 428 virtual size_t adjust_object_size_v(size_t size) const { return size; } | |
| 429 | |
| 430 protected: | |
| 431 // Used during compaction. | |
| 432 HeapWord* _first_dead; | |
| 433 HeapWord* _end_of_live; | |
| 434 | |
| 435 // Minimum size of a free block. | |
| 436 virtual size_t minimum_free_block_size() const = 0; | |
| 437 | |
| 438 // This the function is invoked when an allocation of an object covering | |
| 439 // "start" to "end occurs crosses the threshold; returns the next | |
| 440 // threshold. (The default implementation does nothing.) | |
| 441 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* the_end) { | |
| 442 return end(); | |
| 443 } | |
| 444 | |
| 445 // Requires "allowed_deadspace_words > 0", that "q" is the start of a | |
| 446 // free block of the given "word_len", and that "q", were it an object, | |
| 447 // would not move if forwared. If the size allows, fill the free | |
| 448 // block with an object, to prevent excessive compaction. Returns "true" | |
| 449 // iff the free region was made deadspace, and modifies | |
| 450 // "allowed_deadspace_words" to reflect the number of available deadspace | |
| 451 // words remaining after this operation. | |
| 452 bool insert_deadspace(size_t& allowed_deadspace_words, HeapWord* q, | |
| 453 size_t word_len); | |
| 454 }; | |
| 455 | |
| 456 #define SCAN_AND_FORWARD(cp,scan_limit,block_is_obj,block_size) { \ | |
| 457 /* Compute the new addresses for the live objects and store it in the mark \ | |
| 458 * Used by universe::mark_sweep_phase2() \ | |
| 459 */ \ | |
| 460 HeapWord* compact_top; /* This is where we are currently compacting to. */ \ | |
| 461 \ | |
| 462 /* We're sure to be here before any objects are compacted into this \ | |
| 463 * space, so this is a good time to initialize this: \ | |
| 464 */ \ | |
| 465 set_compaction_top(bottom()); \ | |
| 466 \ | |
| 467 if (cp->space == NULL) { \ | |
| 468 assert(cp->gen != NULL, "need a generation"); \ | |
| 469 assert(cp->threshold == NULL, "just checking"); \ | |
| 470 assert(cp->gen->first_compaction_space() == this, "just checking"); \ | |
| 471 cp->space = cp->gen->first_compaction_space(); \ | |
| 472 compact_top = cp->space->bottom(); \ | |
| 473 cp->space->set_compaction_top(compact_top); \ | |
| 474 cp->threshold = cp->space->initialize_threshold(); \ | |
| 475 } else { \ | |
| 476 compact_top = cp->space->compaction_top(); \ | |
| 477 } \ | |
| 478 \ | |
| 479 /* We allow some amount of garbage towards the bottom of the space, so \ | |
| 480 * we don't start compacting before there is a significant gain to be made.\ | |
| 481 * Occasionally, we want to ensure a full compaction, which is determined \ | |
| 482 * by the MarkSweepAlwaysCompactCount parameter. \ | |
| 483 */ \ | |
| 484 int invocations = SharedHeap::heap()->perm_gen()->stat_record()->invocations;\ | |
| 485 bool skip_dead = ((invocations % MarkSweepAlwaysCompactCount) != 0); \ | |
| 486 \ | |
| 487 size_t allowed_deadspace = 0; \ | |
| 488 if (skip_dead) { \ | |
| 489 int ratio = allowed_dead_ratio(); \ | |
| 490 allowed_deadspace = (capacity() * ratio / 100) / HeapWordSize; \ | |
| 491 } \ | |
| 492 \ | |
| 493 HeapWord* q = bottom(); \ | |
| 494 HeapWord* t = scan_limit(); \ | |
| 495 \ | |
| 496 HeapWord* end_of_live= q; /* One byte beyond the last byte of the last \ | |
| 497 live object. */ \ | |
| 498 HeapWord* first_dead = end();/* The first dead object. */ \ | |
| 499 LiveRange* liveRange = NULL; /* The current live range, recorded in the \ | |
| 500 first header of preceding free area. */ \ | |
| 501 _first_dead = first_dead; \ | |
| 502 \ | |
| 503 const intx interval = PrefetchScanIntervalInBytes; \ | |
| 504 \ | |
| 505 while (q < t) { \ | |
| 506 assert(!block_is_obj(q) || \ | |
| 507 oop(q)->mark()->is_marked() || oop(q)->mark()->is_unlocked() || \ | |
| 508 oop(q)->mark()->has_bias_pattern(), \ | |
| 509 "these are the only valid states during a mark sweep"); \ | |
| 510 if (block_is_obj(q) && oop(q)->is_gc_marked()) { \ | |
| 511 /* prefetch beyond q */ \ | |
| 512 Prefetch::write(q, interval); \ | |
| 513 /* size_t size = oop(q)->size(); changing this for cms for perm gen */\ | |
|
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514 size_t size = block_size(q); \ |
| 0 | 515 compact_top = cp->space->forward(oop(q), size, cp, compact_top); \ |
| 516 q += size; \ | |
| 517 end_of_live = q; \ | |
| 518 } else { \ | |
| 519 /* run over all the contiguous dead objects */ \ | |
| 520 HeapWord* end = q; \ | |
| 521 do { \ | |
| 522 /* prefetch beyond end */ \ | |
| 523 Prefetch::write(end, interval); \ | |
| 524 end += block_size(end); \ | |
| 525 } while (end < t && (!block_is_obj(end) || !oop(end)->is_gc_marked()));\ | |
| 526 \ | |
| 527 /* see if we might want to pretend this object is alive so that \ | |
| 528 * we don't have to compact quite as often. \ | |
| 529 */ \ | |
| 530 if (allowed_deadspace > 0 && q == compact_top) { \ | |
| 531 size_t sz = pointer_delta(end, q); \ | |
| 532 if (insert_deadspace(allowed_deadspace, q, sz)) { \ | |
| 533 compact_top = cp->space->forward(oop(q), sz, cp, compact_top); \ | |
| 534 q = end; \ | |
| 535 end_of_live = end; \ | |
| 536 continue; \ | |
| 537 } \ | |
| 538 } \ | |
| 539 \ | |
| 540 /* otherwise, it really is a free region. */ \ | |
| 541 \ | |
| 542 /* for the previous LiveRange, record the end of the live objects. */ \ | |
| 543 if (liveRange) { \ | |
| 544 liveRange->set_end(q); \ | |
| 545 } \ | |
| 546 \ | |
| 547 /* record the current LiveRange object. \ | |
| 548 * liveRange->start() is overlaid on the mark word. \ | |
| 549 */ \ | |
| 550 liveRange = (LiveRange*)q; \ | |
| 551 liveRange->set_start(end); \ | |
| 552 liveRange->set_end(end); \ | |
| 553 \ | |
| 554 /* see if this is the first dead region. */ \ | |
| 555 if (q < first_dead) { \ | |
| 556 first_dead = q; \ | |
| 557 } \ | |
| 558 \ | |
| 559 /* move on to the next object */ \ | |
| 560 q = end; \ | |
| 561 } \ | |
| 562 } \ | |
| 563 \ | |
| 564 assert(q == t, "just checking"); \ | |
| 565 if (liveRange != NULL) { \ | |
| 566 liveRange->set_end(q); \ | |
| 567 } \ | |
| 568 _end_of_live = end_of_live; \ | |
| 569 if (end_of_live < first_dead) { \ | |
| 570 first_dead = end_of_live; \ | |
| 571 } \ | |
| 572 _first_dead = first_dead; \ | |
| 573 \ | |
| 574 /* save the compaction_top of the compaction space. */ \ | |
| 575 cp->space->set_compaction_top(compact_top); \ | |
| 576 } | |
| 577 | |
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578 #define SCAN_AND_ADJUST_POINTERS(adjust_obj_size) { \ |
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579 /* adjust all the interior pointers to point at the new locations of objects \ |
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580 * Used by MarkSweep::mark_sweep_phase3() */ \ |
| 0 | 581 \ |
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582 HeapWord* q = bottom(); \ |
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583 HeapWord* t = _end_of_live; /* Established by "prepare_for_compaction". */ \ |
| 0 | 584 \ |
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585 assert(_first_dead <= _end_of_live, "Stands to reason, no?"); \ |
| 0 | 586 \ |
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587 if (q < t && _first_dead > q && \ |
| 0 | 588 !oop(q)->is_gc_marked()) { \ |
| 589 /* we have a chunk of the space which hasn't moved and we've \ | |
| 590 * reinitialized the mark word during the previous pass, so we can't \ | |
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591 * use is_gc_marked for the traversal. */ \ |
| 0 | 592 HeapWord* end = _first_dead; \ |
| 593 \ | |
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594 while (q < end) { \ |
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595 /* I originally tried to conjoin "block_start(q) == q" to the \ |
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596 * assertion below, but that doesn't work, because you can't \ |
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597 * accurately traverse previous objects to get to the current one \ |
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598 * after their pointers (including pointers into permGen) have been \ |
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599 * updated, until the actual compaction is done. dld, 4/00 */ \ |
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600 assert(block_is_obj(q), \ |
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601 "should be at block boundaries, and should be looking at objs"); \ |
| 0 | 602 \ |
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603 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::track_interior_pointers(oop(q))); \ |
| 0 | 604 \ |
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605 /* point all the oops to the new location */ \ |
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606 size_t size = oop(q)->adjust_pointers(); \ |
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607 size = adjust_obj_size(size); \ |
| 0 | 608 \ |
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609 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::check_interior_pointers()); \ |
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610 \ |
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611 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::validate_live_oop(oop(q), size)); \ |
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612 \ |
| 0 | 613 q += size; \ |
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614 } \ |
| 0 | 615 \ |
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616 if (_first_dead == t) { \ |
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617 q = t; \ |
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618 } else { \ |
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619 /* $$$ This is funky. Using this to read the previously written \ |
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620 * LiveRange. See also use below. */ \ |
| 0 | 621 q = (HeapWord*)oop(_first_dead)->mark()->decode_pointer(); \ |
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622 } \ |
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623 } \ |
| 0 | 624 \ |
| 625 const intx interval = PrefetchScanIntervalInBytes; \ | |
| 626 \ | |
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627 debug_only(HeapWord* prev_q = NULL); \ |
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628 while (q < t) { \ |
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629 /* prefetch beyond q */ \ |
| 0 | 630 Prefetch::write(q, interval); \ |
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631 if (oop(q)->is_gc_marked()) { \ |
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632 /* q is alive */ \ |
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633 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::track_interior_pointers(oop(q))); \ |
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634 /* point all the oops to the new location */ \ |
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635 size_t size = oop(q)->adjust_pointers(); \ |
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636 size = adjust_obj_size(size); \ |
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637 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::check_interior_pointers()); \ |
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638 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::validate_live_oop(oop(q), size)); \ |
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639 debug_only(prev_q = q); \ |
| 0 | 640 q += size; \ |
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641 } else { \ |
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642 /* q is not a live object, so its mark should point at the next \ |
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643 * live object */ \ |
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644 debug_only(prev_q = q); \ |
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645 q = (HeapWord*) oop(q)->mark()->decode_pointer(); \ |
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646 assert(q > prev_q, "we should be moving forward through memory"); \ |
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647 } \ |
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648 } \ |
| 0 | 649 \ |
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650 assert(q == t, "just checking"); \ |
| 0 | 651 } |
| 652 | |
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653 #define SCAN_AND_COMPACT(obj_size) { \ |
| 0 | 654 /* Copy all live objects to their new location \ |
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655 * Used by MarkSweep::mark_sweep_phase4() */ \ |
| 0 | 656 \ |
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657 HeapWord* q = bottom(); \ |
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658 HeapWord* const t = _end_of_live; \ |
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659 debug_only(HeapWord* prev_q = NULL); \ |
| 0 | 660 \ |
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661 if (q < t && _first_dead > q && \ |
| 0 | 662 !oop(q)->is_gc_marked()) { \ |
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663 debug_only( \ |
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664 /* we have a chunk of the space which hasn't moved and we've reinitialized \ |
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665 * the mark word during the previous pass, so we can't use is_gc_marked for \ |
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666 * the traversal. */ \ |
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667 HeapWord* const end = _first_dead; \ |
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668 \ |
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669 while (q < end) { \ |
| 0 | 670 size_t size = obj_size(q); \ |
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671 assert(!oop(q)->is_gc_marked(), \ |
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672 "should be unmarked (special dense prefix handling)"); \ |
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673 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::live_oop_moved_to(q, size, q)); \ |
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674 debug_only(prev_q = q); \ |
| 0 | 675 q += size; \ |
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676 } \ |
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677 ) /* debug_only */ \ |
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678 \ |
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679 if (_first_dead == t) { \ |
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680 q = t; \ |
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681 } else { \ |
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682 /* $$$ Funky */ \ |
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683 q = (HeapWord*) oop(_first_dead)->mark()->decode_pointer(); \ |
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684 } \ |
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685 } \ |
| 0 | 686 \ |
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687 const intx scan_interval = PrefetchScanIntervalInBytes; \ |
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688 const intx copy_interval = PrefetchCopyIntervalInBytes; \ |
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689 while (q < t) { \ |
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690 if (!oop(q)->is_gc_marked()) { \ |
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691 /* mark is pointer to next marked oop */ \ |
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692 debug_only(prev_q = q); \ |
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693 q = (HeapWord*) oop(q)->mark()->decode_pointer(); \ |
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694 assert(q > prev_q, "we should be moving forward through memory"); \ |
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695 } else { \ |
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696 /* prefetch beyond q */ \ |
| 0 | 697 Prefetch::read(q, scan_interval); \ |
| 698 \ | |
| 699 /* size and destination */ \ | |
| 700 size_t size = obj_size(q); \ | |
| 701 HeapWord* compaction_top = (HeapWord*)oop(q)->forwardee(); \ | |
| 702 \ | |
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703 /* prefetch beyond compaction_top */ \ |
| 0 | 704 Prefetch::write(compaction_top, copy_interval); \ |
| 705 \ | |
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706 /* copy object and reinit its mark */ \ |
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707 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::live_oop_moved_to(q, size, \ |
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708 compaction_top)); \ |
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709 assert(q != compaction_top, "everything in this pass should be moving"); \ |
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710 Copy::aligned_conjoint_words(q, compaction_top, size); \ |
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711 oop(compaction_top)->init_mark(); \ |
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712 assert(oop(compaction_top)->klass() != NULL, "should have a class"); \ |
| 0 | 713 \ |
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714 debug_only(prev_q = q); \ |
| 0 | 715 q += size; \ |
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716 } \ |
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717 } \ |
| 0 | 718 \ |
| 719 /* Reset space after compaction is complete */ \ | |
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720 reset_after_compaction(); \ |
| 0 | 721 /* We do this clear, below, since it has overloaded meanings for some */ \ |
| 722 /* space subtypes. For example, OffsetTableContigSpace's that were */ \ | |
| 723 /* compacted into will have had their offset table thresholds updated */ \ | |
| 724 /* continuously, but those that weren't need to have their thresholds */ \ | |
| 725 /* re-initialized. Also mangles unused area for debugging. */ \ | |
| 726 if (is_empty()) { \ | |
| 727 clear(); \ | |
| 728 } else { \ | |
| 729 if (ZapUnusedHeapArea) mangle_unused_area(); \ | |
| 730 } \ | |
| 731 } | |
| 732 | |
| 733 // A space in which the free area is contiguous. It therefore supports | |
| 734 // faster allocation, and compaction. | |
| 735 class ContiguousSpace: public CompactibleSpace { | |
| 736 friend class OneContigSpaceCardGeneration; | |
| 737 friend class VMStructs; | |
| 738 protected: | |
| 739 HeapWord* _top; | |
| 740 HeapWord* _concurrent_iteration_safe_limit; | |
| 741 | |
| 742 // Allocation helpers (return NULL if full). | |
| 743 inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value); | |
| 744 inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value); | |
| 745 | |
| 746 public: | |
| 747 virtual void initialize(MemRegion mr, bool clear_space); | |
| 748 | |
| 749 // Accessors | |
| 750 HeapWord* top() const { return _top; } | |
| 751 void set_top(HeapWord* value) { _top = value; } | |
| 752 | |
| 753 void set_saved_mark() { _saved_mark_word = top(); } | |
| 754 void reset_saved_mark() { _saved_mark_word = bottom(); } | |
| 755 | |
| 756 virtual void clear(); | |
| 757 | |
| 758 WaterMark bottom_mark() { return WaterMark(this, bottom()); } | |
| 759 WaterMark top_mark() { return WaterMark(this, top()); } | |
| 760 WaterMark saved_mark() { return WaterMark(this, saved_mark_word()); } | |
| 761 bool saved_mark_at_top() const { return saved_mark_word() == top(); } | |
| 762 | |
| 763 void mangle_unused_area(); | |
| 764 void mangle_region(MemRegion mr); | |
| 765 | |
| 766 // Size computations: sizes in bytes. | |
| 767 size_t capacity() const { return byte_size(bottom(), end()); } | |
| 768 size_t used() const { return byte_size(bottom(), top()); } | |
| 769 size_t free() const { return byte_size(top(), end()); } | |
| 770 | |
| 771 // Override from space. | |
| 772 bool is_in(const void* p) const; | |
| 773 | |
| 774 virtual bool is_free_block(const HeapWord* p) const; | |
| 775 | |
| 776 // In a contiguous space we have a more obvious bound on what parts | |
| 777 // contain objects. | |
| 778 MemRegion used_region() const { return MemRegion(bottom(), top()); } | |
| 779 | |
| 780 MemRegion used_region_at_save_marks() const { | |
| 781 return MemRegion(bottom(), saved_mark_word()); | |
| 782 } | |
| 783 | |
| 784 // Allocation (return NULL if full) | |
| 785 virtual HeapWord* allocate(size_t word_size); | |
| 786 virtual HeapWord* par_allocate(size_t word_size); | |
| 787 | |
| 788 virtual bool obj_allocated_since_save_marks(const oop obj) const { | |
| 789 return (HeapWord*)obj >= saved_mark_word(); | |
| 790 } | |
| 791 | |
| 792 // Iteration | |
| 793 void oop_iterate(OopClosure* cl); | |
| 794 void oop_iterate(MemRegion mr, OopClosure* cl); | |
| 795 void object_iterate(ObjectClosure* blk); | |
| 796 void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl); | |
| 797 // iterates on objects up to the safe limit | |
| 798 HeapWord* object_iterate_careful(ObjectClosureCareful* cl); | |
| 799 inline HeapWord* concurrent_iteration_safe_limit(); | |
| 800 // changes the safe limit, all objects from bottom() to the new | |
| 801 // limit should be properly initialized | |
| 802 inline void set_concurrent_iteration_safe_limit(HeapWord* new_limit); | |
| 803 | |
| 804 #ifndef SERIALGC | |
| 805 // In support of parallel oop_iterate. | |
| 806 #define ContigSpace_PAR_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ | |
| 807 void par_oop_iterate(MemRegion mr, OopClosureType* blk); | |
| 808 | |
| 809 ALL_PAR_OOP_ITERATE_CLOSURES(ContigSpace_PAR_OOP_ITERATE_DECL) | |
| 810 #undef ContigSpace_PAR_OOP_ITERATE_DECL | |
| 811 #endif // SERIALGC | |
| 812 | |
| 813 // Compaction support | |
| 814 virtual void reset_after_compaction() { | |
| 815 assert(compaction_top() >= bottom() && compaction_top() <= end(), "should point inside space"); | |
| 816 set_top(compaction_top()); | |
| 817 // set new iteration safe limit | |
| 818 set_concurrent_iteration_safe_limit(compaction_top()); | |
| 819 } | |
| 820 virtual size_t minimum_free_block_size() const { return 0; } | |
| 821 | |
| 822 // Override. | |
| 823 DirtyCardToOopClosure* new_dcto_cl(OopClosure* cl, | |
| 824 CardTableModRefBS::PrecisionStyle precision, | |
| 825 HeapWord* boundary = NULL); | |
| 826 | |
| 827 // Apply "blk->do_oop" to the addresses of all reference fields in objects | |
| 828 // starting with the _saved_mark_word, which was noted during a generation's | |
| 829 // save_marks and is required to denote the head of an object. | |
| 830 // Fields in objects allocated by applications of the closure | |
| 831 // *are* included in the iteration. | |
| 832 // Updates _saved_mark_word to point to just after the last object | |
| 833 // iterated over. | |
| 834 #define ContigSpace_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ | |
| 835 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk); | |
| 836 | |
| 837 ALL_SINCE_SAVE_MARKS_CLOSURES(ContigSpace_OOP_SINCE_SAVE_MARKS_DECL) | |
| 838 #undef ContigSpace_OOP_SINCE_SAVE_MARKS_DECL | |
| 839 | |
| 840 // Same as object_iterate, but starting from "mark", which is required | |
| 841 // to denote the start of an object. Objects allocated by | |
| 842 // applications of the closure *are* included in the iteration. | |
| 843 virtual void object_iterate_from(WaterMark mark, ObjectClosure* blk); | |
| 844 | |
| 845 // Very inefficient implementation. | |
| 846 virtual HeapWord* block_start(const void* p) const; | |
| 847 size_t block_size(const HeapWord* p) const; | |
| 848 // If a block is in the allocated area, it is an object. | |
| 849 bool block_is_obj(const HeapWord* p) const { return p < top(); } | |
| 850 | |
| 851 // Addresses for inlined allocation | |
| 852 HeapWord** top_addr() { return &_top; } | |
| 853 HeapWord** end_addr() { return &_end; } | |
| 854 | |
| 855 // Overrides for more efficient compaction support. | |
| 856 void prepare_for_compaction(CompactPoint* cp); | |
| 857 | |
| 858 // PrintHeapAtGC support. | |
| 859 virtual void print_on(outputStream* st) const; | |
| 860 | |
| 861 // Checked dynamic downcasts. | |
| 862 virtual ContiguousSpace* toContiguousSpace() { | |
| 863 return this; | |
| 864 } | |
| 865 | |
| 866 // Debugging | |
| 867 virtual void verify(bool allow_dirty) const; | |
| 868 | |
| 869 // Used to increase collection frequency. "factor" of 0 means entire | |
| 870 // space. | |
| 871 void allocate_temporary_filler(int factor); | |
| 872 | |
| 873 }; | |
| 874 | |
| 875 | |
| 876 // A dirty card to oop closure that does filtering. | |
| 877 // It knows how to filter out objects that are outside of the _boundary. | |
| 878 class Filtering_DCTOC : public DirtyCardToOopClosure { | |
| 879 protected: | |
| 880 // Override. | |
| 881 void walk_mem_region(MemRegion mr, | |
| 882 HeapWord* bottom, HeapWord* top); | |
| 883 | |
| 884 // Walk the given memory region, from bottom to top, applying | |
| 885 // the given oop closure to (possibly) all objects found. The | |
| 886 // given oop closure may or may not be the same as the oop | |
| 887 // closure with which this closure was created, as it may | |
| 888 // be a filtering closure which makes use of the _boundary. | |
| 889 // We offer two signatures, so the FilteringClosure static type is | |
| 890 // apparent. | |
| 891 virtual void walk_mem_region_with_cl(MemRegion mr, | |
| 892 HeapWord* bottom, HeapWord* top, | |
| 893 OopClosure* cl) = 0; | |
| 894 virtual void walk_mem_region_with_cl(MemRegion mr, | |
| 895 HeapWord* bottom, HeapWord* top, | |
| 896 FilteringClosure* cl) = 0; | |
| 897 | |
| 898 public: | |
| 899 Filtering_DCTOC(Space* sp, OopClosure* cl, | |
| 900 CardTableModRefBS::PrecisionStyle precision, | |
| 901 HeapWord* boundary) : | |
| 902 DirtyCardToOopClosure(sp, cl, precision, boundary) {} | |
| 903 }; | |
| 904 | |
| 905 // A dirty card to oop closure for contiguous spaces | |
| 906 // (ContiguousSpace and sub-classes). | |
| 907 // It is a FilteringClosure, as defined above, and it knows: | |
| 908 // | |
| 909 // 1. That the actual top of any area in a memory region | |
| 910 // contained by the space is bounded by the end of the contiguous | |
| 911 // region of the space. | |
| 912 // 2. That the space is really made up of objects and not just | |
| 913 // blocks. | |
| 914 | |
| 915 class ContiguousSpaceDCTOC : public Filtering_DCTOC { | |
| 916 protected: | |
| 917 // Overrides. | |
| 918 HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj); | |
| 919 | |
| 920 virtual void walk_mem_region_with_cl(MemRegion mr, | |
| 921 HeapWord* bottom, HeapWord* top, | |
| 922 OopClosure* cl); | |
| 923 virtual void walk_mem_region_with_cl(MemRegion mr, | |
| 924 HeapWord* bottom, HeapWord* top, | |
| 925 FilteringClosure* cl); | |
| 926 | |
| 927 public: | |
| 928 ContiguousSpaceDCTOC(ContiguousSpace* sp, OopClosure* cl, | |
| 929 CardTableModRefBS::PrecisionStyle precision, | |
| 930 HeapWord* boundary) : | |
| 931 Filtering_DCTOC(sp, cl, precision, boundary) | |
| 932 {} | |
| 933 }; | |
| 934 | |
| 935 | |
| 936 // Class EdenSpace describes eden-space in new generation. | |
| 937 | |
| 938 class DefNewGeneration; | |
| 939 | |
| 940 class EdenSpace : public ContiguousSpace { | |
| 941 friend class VMStructs; | |
| 942 private: | |
| 943 DefNewGeneration* _gen; | |
| 944 | |
| 945 // _soft_end is used as a soft limit on allocation. As soft limits are | |
| 946 // reached, the slow-path allocation code can invoke other actions and then | |
| 947 // adjust _soft_end up to a new soft limit or to end(). | |
| 948 HeapWord* _soft_end; | |
| 949 | |
| 950 public: | |
| 951 EdenSpace(DefNewGeneration* gen) : _gen(gen) { _soft_end = NULL; } | |
| 952 | |
| 953 // Get/set just the 'soft' limit. | |
| 954 HeapWord* soft_end() { return _soft_end; } | |
| 955 HeapWord** soft_end_addr() { return &_soft_end; } | |
| 956 void set_soft_end(HeapWord* value) { _soft_end = value; } | |
| 957 | |
| 958 // Override. | |
| 959 void clear(); | |
| 960 | |
| 961 // Set both the 'hard' and 'soft' limits (_end and _soft_end). | |
| 962 void set_end(HeapWord* value) { | |
| 963 set_soft_end(value); | |
| 964 ContiguousSpace::set_end(value); | |
| 965 } | |
| 966 | |
| 967 // Allocation (return NULL if full) | |
| 968 HeapWord* allocate(size_t word_size); | |
| 969 HeapWord* par_allocate(size_t word_size); | |
| 970 }; | |
| 971 | |
| 972 // Class ConcEdenSpace extends EdenSpace for the sake of safe | |
| 973 // allocation while soft-end is being modified concurrently | |
| 974 | |
| 975 class ConcEdenSpace : public EdenSpace { | |
| 976 public: | |
| 977 ConcEdenSpace(DefNewGeneration* gen) : EdenSpace(gen) { } | |
| 978 | |
| 979 // Allocation (return NULL if full) | |
| 980 HeapWord* par_allocate(size_t word_size); | |
| 981 }; | |
| 982 | |
| 983 | |
| 984 // A ContigSpace that Supports an efficient "block_start" operation via | |
| 985 // a BlockOffsetArray (whose BlockOffsetSharedArray may be shared with | |
| 986 // other spaces.) This is the abstract base class for old generation | |
| 987 // (tenured, perm) spaces. | |
| 988 | |
| 989 class OffsetTableContigSpace: public ContiguousSpace { | |
| 990 friend class VMStructs; | |
| 991 protected: | |
| 992 BlockOffsetArrayContigSpace _offsets; | |
| 993 Mutex _par_alloc_lock; | |
| 994 | |
| 995 public: | |
| 996 // Constructor | |
| 997 OffsetTableContigSpace(BlockOffsetSharedArray* sharedOffsetArray, | |
| 998 MemRegion mr); | |
| 999 | |
| 1000 void set_bottom(HeapWord* value); | |
| 1001 void set_end(HeapWord* value); | |
| 1002 | |
| 1003 void clear(); | |
| 1004 | |
| 1005 inline HeapWord* block_start(const void* p) const; | |
| 1006 | |
| 1007 // Add offset table update. | |
| 1008 virtual inline HeapWord* allocate(size_t word_size); | |
| 1009 inline HeapWord* par_allocate(size_t word_size); | |
| 1010 | |
| 1011 // MarkSweep support phase3 | |
| 1012 virtual HeapWord* initialize_threshold(); | |
| 1013 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); | |
| 1014 | |
| 1015 virtual void print_on(outputStream* st) const; | |
| 1016 | |
| 1017 // Debugging | |
| 1018 void verify(bool allow_dirty) const; | |
| 1019 | |
| 1020 // Shared space support | |
| 1021 void serialize_block_offset_array_offsets(SerializeOopClosure* soc); | |
| 1022 }; | |
| 1023 | |
| 1024 | |
| 1025 // Class TenuredSpace is used by TenuredGeneration | |
| 1026 | |
| 1027 class TenuredSpace: public OffsetTableContigSpace { | |
| 1028 friend class VMStructs; | |
| 1029 protected: | |
| 1030 // Mark sweep support | |
| 1031 int allowed_dead_ratio() const; | |
| 1032 public: | |
| 1033 // Constructor | |
| 1034 TenuredSpace(BlockOffsetSharedArray* sharedOffsetArray, | |
| 1035 MemRegion mr) : | |
| 1036 OffsetTableContigSpace(sharedOffsetArray, mr) {} | |
| 1037 }; | |
| 1038 | |
| 1039 | |
| 1040 // Class ContigPermSpace is used by CompactingPermGen | |
| 1041 | |
| 1042 class ContigPermSpace: public OffsetTableContigSpace { | |
| 1043 friend class VMStructs; | |
| 1044 protected: | |
| 1045 // Mark sweep support | |
| 1046 int allowed_dead_ratio() const; | |
| 1047 public: | |
| 1048 // Constructor | |
| 1049 ContigPermSpace(BlockOffsetSharedArray* sharedOffsetArray, MemRegion mr) : | |
| 1050 OffsetTableContigSpace(sharedOffsetArray, mr) {} | |
| 1051 }; |