Mercurial > hg > truffle
annotate src/share/vm/memory/space.hpp @ 948:89e0543e1737
6884624: Update copyright year
Summary: Update copyright for files that have been modified in 2009 through Septermber
Reviewed-by: tbell, ohair
| author | xdono |
|---|---|
| date | Tue, 22 Sep 2009 14:06:10 -0700 |
| parents | df6caf649ff7 |
| children | c18cbe5936b8 |
| rev | line source |
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| 0 | 1 /* |
| 579 | 2 * Copyright 1997-2009 Sun Microsystems, Inc. All Rights Reserved. |
| 0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
| 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 | |
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108 virtual HeapWord* saved_mark_word() const { return _saved_mark_word; } |
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109 |
| 0 | 110 void set_saved_mark_word(HeapWord* p) { _saved_mark_word = p; } |
| 111 | |
| 112 MemRegionClosure* preconsumptionDirtyCardClosure() const { | |
| 113 return _preconsumptionDirtyCardClosure; | |
| 114 } | |
| 115 void setPreconsumptionDirtyCardClosure(MemRegionClosure* cl) { | |
| 116 _preconsumptionDirtyCardClosure = cl; | |
| 117 } | |
| 118 | |
| 119 // Returns a subregion of the space containing all the objects in | |
| 120 // the space. | |
| 121 virtual MemRegion used_region() const { return MemRegion(bottom(), end()); } | |
| 122 | |
| 123 // Returns a region that is guaranteed to contain (at least) all objects | |
| 124 // allocated at the time of the last call to "save_marks". If the space | |
| 125 // initializes its DirtyCardToOopClosure's specifying the "contig" option | |
| 126 // (that is, if the space is contiguous), then this region must contain only | |
| 127 // such objects: the memregion will be from the bottom of the region to the | |
| 128 // saved mark. Otherwise, the "obj_allocated_since_save_marks" method of | |
| 129 // the space must distiguish between objects in the region allocated before | |
| 130 // and after the call to save marks. | |
| 131 virtual MemRegion used_region_at_save_marks() const { | |
| 132 return MemRegion(bottom(), saved_mark_word()); | |
| 133 } | |
| 134 | |
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135 // Initialization. |
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136 // "initialize" should be called once on a space, before it is used for |
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137 // any purpose. The "mr" arguments gives the bounds of the space, and |
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138 // the "clear_space" argument should be true unless the memory in "mr" is |
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139 // known to be zeroed. |
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140 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); |
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141 |
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142 // The "clear" method must be called on a region that may have |
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143 // had allocation performed in it, but is now to be considered empty. |
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144 virtual void clear(bool mangle_space); |
| 0 | 145 |
| 146 // For detecting GC bugs. Should only be called at GC boundaries, since | |
| 147 // some unused space may be used as scratch space during GC's. | |
| 148 // Default implementation does nothing. We also call this when expanding | |
| 149 // a space to satisfy an allocation request. See bug #4668531 | |
| 150 virtual void mangle_unused_area() {} | |
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151 virtual void mangle_unused_area_complete() {} |
| 0 | 152 virtual void mangle_region(MemRegion mr) {} |
| 153 | |
| 154 // Testers | |
| 155 bool is_empty() const { return used() == 0; } | |
| 156 bool not_empty() const { return used() > 0; } | |
| 157 | |
| 158 // Returns true iff the given the space contains the | |
| 159 // given address as part of an allocated object. For | |
| 160 // ceratin kinds of spaces, this might be a potentially | |
| 161 // expensive operation. To prevent performance problems | |
| 162 // on account of its inadvertent use in product jvm's, | |
| 163 // we restrict its use to assertion checks only. | |
| 164 virtual bool is_in(const void* p) const; | |
| 165 | |
| 166 // Returns true iff the given reserved memory of the space contains the | |
| 167 // given address. | |
| 168 bool is_in_reserved(const void* p) const { return _bottom <= p && p < _end; } | |
| 169 | |
| 170 // Returns true iff the given block is not allocated. | |
| 171 virtual bool is_free_block(const HeapWord* p) const = 0; | |
| 172 | |
| 173 // Test whether p is double-aligned | |
| 174 static bool is_aligned(void* p) { | |
| 175 return ((intptr_t)p & (sizeof(double)-1)) == 0; | |
| 176 } | |
| 177 | |
| 178 // Size computations. Sizes are in bytes. | |
| 179 size_t capacity() const { return byte_size(bottom(), end()); } | |
| 180 virtual size_t used() const = 0; | |
| 181 virtual size_t free() const = 0; | |
| 182 | |
| 183 // Iterate over all the ref-containing fields of all objects in the | |
| 184 // space, calling "cl.do_oop" on each. Fields in objects allocated by | |
| 185 // applications of the closure are not included in the iteration. | |
| 186 virtual void oop_iterate(OopClosure* cl); | |
| 187 | |
| 188 // Same as above, restricted to the intersection of a memory region and | |
| 189 // the space. Fields in objects allocated by applications of the closure | |
| 190 // are not included in the iteration. | |
| 191 virtual void oop_iterate(MemRegion mr, OopClosure* cl) = 0; | |
| 192 | |
| 193 // Iterate over all objects in the space, calling "cl.do_object" on | |
| 194 // each. Objects allocated by applications of the closure are not | |
| 195 // included in the iteration. | |
| 196 virtual void object_iterate(ObjectClosure* blk) = 0; | |
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197 // Similar to object_iterate() except only iterates over |
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198 // objects whose internal references point to objects in the space. |
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199 virtual void safe_object_iterate(ObjectClosure* blk) = 0; |
| 0 | 200 |
| 201 // Iterate over all objects that intersect with mr, calling "cl->do_object" | |
| 202 // on each. There is an exception to this: if this closure has already | |
| 203 // been invoked on an object, it may skip such objects in some cases. This is | |
| 204 // Most likely to happen in an "upwards" (ascending address) iteration of | |
| 205 // MemRegions. | |
| 206 virtual void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl); | |
| 207 | |
| 208 // Iterate over as many initialized objects in the space as possible, | |
| 209 // calling "cl.do_object_careful" on each. Return NULL if all objects | |
| 210 // in the space (at the start of the iteration) were iterated over. | |
| 211 // Return an address indicating the extent of the iteration in the | |
| 212 // event that the iteration had to return because of finding an | |
| 213 // uninitialized object in the space, or if the closure "cl" | |
| 214 // signalled early termination. | |
| 215 virtual HeapWord* object_iterate_careful(ObjectClosureCareful* cl); | |
| 216 virtual HeapWord* object_iterate_careful_m(MemRegion mr, | |
| 217 ObjectClosureCareful* cl); | |
| 218 | |
| 219 // Create and return a new dirty card to oop closure. Can be | |
| 220 // overriden to return the appropriate type of closure | |
| 221 // depending on the type of space in which the closure will | |
| 222 // operate. ResourceArea allocated. | |
| 223 virtual DirtyCardToOopClosure* new_dcto_cl(OopClosure* cl, | |
| 224 CardTableModRefBS::PrecisionStyle precision, | |
| 225 HeapWord* boundary = NULL); | |
| 226 | |
| 227 // If "p" is in the space, returns the address of the start of the | |
| 228 // "block" that contains "p". We say "block" instead of "object" since | |
| 229 // some heaps may not pack objects densely; a chunk may either be an | |
| 230 // object or a non-object. If "p" is not in the space, return NULL. | |
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231 virtual HeapWord* block_start_const(const void* p) const = 0; |
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232 |
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233 // The non-const version may have benevolent side effects on the data |
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234 // structure supporting these calls, possibly speeding up future calls. |
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235 // The default implementation, however, is simply to call the const |
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236 // version. |
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237 inline virtual HeapWord* block_start(const void* p); |
| 0 | 238 |
| 239 // Requires "addr" to be the start of a chunk, and returns its size. | |
| 240 // "addr + size" is required to be the start of a new chunk, or the end | |
| 241 // of the active area of the heap. | |
| 242 virtual size_t block_size(const HeapWord* addr) const = 0; | |
| 243 | |
| 244 // Requires "addr" to be the start of a block, and returns "TRUE" iff | |
| 245 // the block is an object. | |
| 246 virtual bool block_is_obj(const HeapWord* addr) const = 0; | |
| 247 | |
| 248 // Requires "addr" to be the start of a block, and returns "TRUE" iff | |
| 249 // the block is an object and the object is alive. | |
| 250 virtual bool obj_is_alive(const HeapWord* addr) const; | |
| 251 | |
| 252 // Allocation (return NULL if full). Assumes the caller has established | |
| 253 // mutually exclusive access to the space. | |
| 254 virtual HeapWord* allocate(size_t word_size) = 0; | |
| 255 | |
| 256 // Allocation (return NULL if full). Enforces mutual exclusion internally. | |
| 257 virtual HeapWord* par_allocate(size_t word_size) = 0; | |
| 258 | |
| 259 // Returns true if this object has been allocated since a | |
| 260 // generation's "save_marks" call. | |
| 261 virtual bool obj_allocated_since_save_marks(const oop obj) const = 0; | |
| 262 | |
| 263 // Mark-sweep-compact support: all spaces can update pointers to objects | |
| 264 // moving as a part of compaction. | |
| 265 virtual void adjust_pointers(); | |
| 266 | |
| 267 // PrintHeapAtGC support | |
| 268 virtual void print() const; | |
| 269 virtual void print_on(outputStream* st) const; | |
| 270 virtual void print_short() const; | |
| 271 virtual void print_short_on(outputStream* st) const; | |
| 272 | |
| 273 | |
| 274 // Accessor for parallel sequential tasks. | |
| 275 SequentialSubTasksDone* par_seq_tasks() { return &_par_seq_tasks; } | |
| 276 | |
| 277 // IF "this" is a ContiguousSpace, return it, else return NULL. | |
| 278 virtual ContiguousSpace* toContiguousSpace() { | |
| 279 return NULL; | |
| 280 } | |
| 281 | |
| 282 // Debugging | |
| 283 virtual void verify(bool allow_dirty) const = 0; | |
| 284 }; | |
| 285 | |
| 286 // A MemRegionClosure (ResourceObj) whose "do_MemRegion" function applies an | |
| 287 // OopClosure to (the addresses of) all the ref-containing fields that could | |
| 288 // be modified by virtue of the given MemRegion being dirty. (Note that | |
| 289 // because of the imprecise nature of the write barrier, this may iterate | |
| 290 // over oops beyond the region.) | |
| 291 // This base type for dirty card to oop closures handles memory regions | |
| 292 // in non-contiguous spaces with no boundaries, and should be sub-classed | |
| 293 // to support other space types. See ContiguousDCTOC for a sub-class | |
| 294 // that works with ContiguousSpaces. | |
| 295 | |
| 296 class DirtyCardToOopClosure: public MemRegionClosureRO { | |
| 297 protected: | |
| 298 OopClosure* _cl; | |
| 299 Space* _sp; | |
| 300 CardTableModRefBS::PrecisionStyle _precision; | |
| 301 HeapWord* _boundary; // If non-NULL, process only non-NULL oops | |
| 302 // pointing below boundary. | |
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303 HeapWord* _min_done; // ObjHeadPreciseArray precision requires |
| 0 | 304 // a downwards traversal; this is the |
| 305 // lowest location already done (or, | |
| 306 // alternatively, the lowest address that | |
| 307 // shouldn't be done again. NULL means infinity.) | |
| 308 NOT_PRODUCT(HeapWord* _last_bottom;) | |
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309 NOT_PRODUCT(HeapWord* _last_explicit_min_done;) |
| 0 | 310 |
| 311 // Get the actual top of the area on which the closure will | |
| 312 // operate, given where the top is assumed to be (the end of the | |
| 313 // memory region passed to do_MemRegion) and where the object | |
| 314 // at the top is assumed to start. For example, an object may | |
| 315 // start at the top but actually extend past the assumed top, | |
| 316 // in which case the top becomes the end of the object. | |
| 317 virtual HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj); | |
| 318 | |
| 319 // Walk the given memory region from bottom to (actual) top | |
| 320 // looking for objects and applying the oop closure (_cl) to | |
| 321 // them. The base implementation of this treats the area as | |
| 322 // blocks, where a block may or may not be an object. Sub- | |
| 323 // classes should override this to provide more accurate | |
| 324 // or possibly more efficient walking. | |
| 325 virtual void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top); | |
| 326 | |
| 327 public: | |
| 328 DirtyCardToOopClosure(Space* sp, OopClosure* cl, | |
| 329 CardTableModRefBS::PrecisionStyle precision, | |
| 330 HeapWord* boundary) : | |
| 331 _sp(sp), _cl(cl), _precision(precision), _boundary(boundary), | |
| 332 _min_done(NULL) { | |
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333 NOT_PRODUCT(_last_bottom = NULL); |
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334 NOT_PRODUCT(_last_explicit_min_done = NULL); |
| 0 | 335 } |
| 336 | |
| 337 void do_MemRegion(MemRegion mr); | |
| 338 | |
| 339 void set_min_done(HeapWord* min_done) { | |
| 340 _min_done = min_done; | |
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341 NOT_PRODUCT(_last_explicit_min_done = _min_done); |
| 0 | 342 } |
| 343 #ifndef PRODUCT | |
| 344 void set_last_bottom(HeapWord* last_bottom) { | |
| 345 _last_bottom = last_bottom; | |
| 346 } | |
| 347 #endif | |
| 348 }; | |
| 349 | |
| 350 // A structure to represent a point at which objects are being copied | |
| 351 // during compaction. | |
| 352 class CompactPoint : public StackObj { | |
| 353 public: | |
| 354 Generation* gen; | |
| 355 CompactibleSpace* space; | |
| 356 HeapWord* threshold; | |
| 357 CompactPoint(Generation* _gen, CompactibleSpace* _space, | |
| 358 HeapWord* _threshold) : | |
| 359 gen(_gen), space(_space), threshold(_threshold) {} | |
| 360 }; | |
| 361 | |
| 362 | |
| 363 // A space that supports compaction operations. This is usually, but not | |
| 364 // necessarily, a space that is normally contiguous. But, for example, a | |
| 365 // free-list-based space whose normal collection is a mark-sweep without | |
| 366 // compaction could still support compaction in full GC's. | |
| 367 | |
| 368 class CompactibleSpace: public Space { | |
| 369 friend class VMStructs; | |
| 370 friend class CompactibleFreeListSpace; | |
| 371 friend class CompactingPermGenGen; | |
| 372 friend class CMSPermGenGen; | |
| 373 private: | |
| 374 HeapWord* _compaction_top; | |
| 375 CompactibleSpace* _next_compaction_space; | |
| 376 | |
| 377 public: | |
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378 CompactibleSpace() : |
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379 _compaction_top(NULL), _next_compaction_space(NULL) {} |
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380 |
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381 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); |
| 356 | 382 virtual void clear(bool mangle_space); |
| 0 | 383 |
| 384 // Used temporarily during a compaction phase to hold the value | |
| 385 // top should have when compaction is complete. | |
| 386 HeapWord* compaction_top() const { return _compaction_top; } | |
| 387 | |
| 388 void set_compaction_top(HeapWord* value) { | |
| 389 assert(value == NULL || (value >= bottom() && value <= end()), | |
| 390 "should point inside space"); | |
| 391 _compaction_top = value; | |
| 392 } | |
| 393 | |
| 394 // Perform operations on the space needed after a compaction | |
| 395 // has been performed. | |
| 396 virtual void reset_after_compaction() {} | |
| 397 | |
| 398 // Returns the next space (in the current generation) to be compacted in | |
| 399 // the global compaction order. Also is used to select the next | |
| 400 // space into which to compact. | |
| 401 | |
| 402 virtual CompactibleSpace* next_compaction_space() const { | |
| 403 return _next_compaction_space; | |
| 404 } | |
| 405 | |
| 406 void set_next_compaction_space(CompactibleSpace* csp) { | |
| 407 _next_compaction_space = csp; | |
| 408 } | |
| 409 | |
| 410 // MarkSweep support phase2 | |
| 411 | |
| 412 // Start the process of compaction of the current space: compute | |
| 413 // post-compaction addresses, and insert forwarding pointers. The fields | |
| 414 // "cp->gen" and "cp->compaction_space" are the generation and space into | |
| 415 // which we are currently compacting. This call updates "cp" as necessary, | |
| 416 // and leaves the "compaction_top" of the final value of | |
| 417 // "cp->compaction_space" up-to-date. Offset tables may be updated in | |
| 418 // this phase as if the final copy had occurred; if so, "cp->threshold" | |
| 419 // indicates when the next such action should be taken. | |
| 420 virtual void prepare_for_compaction(CompactPoint* cp); | |
| 421 // MarkSweep support phase3 | |
| 422 virtual void adjust_pointers(); | |
| 423 // MarkSweep support phase4 | |
| 424 virtual void compact(); | |
| 425 | |
| 426 // The maximum percentage of objects that can be dead in the compacted | |
| 427 // live part of a compacted space ("deadwood" support.) | |
| 438 | 428 virtual size_t allowed_dead_ratio() const { return 0; }; |
| 0 | 429 |
| 430 // Some contiguous spaces may maintain some data structures that should | |
| 431 // be updated whenever an allocation crosses a boundary. This function | |
| 432 // returns the first such boundary. | |
| 433 // (The default implementation returns the end of the space, so the | |
| 434 // boundary is never crossed.) | |
| 435 virtual HeapWord* initialize_threshold() { return end(); } | |
| 436 | |
| 437 // "q" is an object of the given "size" that should be forwarded; | |
| 438 // "cp" names the generation ("gen") and containing "this" (which must | |
| 439 // also equal "cp->space"). "compact_top" is where in "this" the | |
| 440 // next object should be forwarded to. If there is room in "this" for | |
| 441 // the object, insert an appropriate forwarding pointer in "q". | |
| 442 // If not, go to the next compaction space (there must | |
| 443 // be one, since compaction must succeed -- we go to the first space of | |
| 444 // the previous generation if necessary, updating "cp"), reset compact_top | |
| 445 // and then forward. In either case, returns the new value of "compact_top". | |
| 446 // If the forwarding crosses "cp->threshold", invokes the "cross_threhold" | |
| 447 // function of the then-current compaction space, and updates "cp->threshold | |
| 448 // accordingly". | |
| 449 virtual HeapWord* forward(oop q, size_t size, CompactPoint* cp, | |
| 450 HeapWord* compact_top); | |
| 451 | |
| 452 // Return a size with adjusments as required of the space. | |
| 453 virtual size_t adjust_object_size_v(size_t size) const { return size; } | |
| 454 | |
| 455 protected: | |
| 456 // Used during compaction. | |
| 457 HeapWord* _first_dead; | |
| 458 HeapWord* _end_of_live; | |
| 459 | |
| 460 // Minimum size of a free block. | |
| 461 virtual size_t minimum_free_block_size() const = 0; | |
| 462 | |
| 463 // This the function is invoked when an allocation of an object covering | |
| 464 // "start" to "end occurs crosses the threshold; returns the next | |
| 465 // threshold. (The default implementation does nothing.) | |
| 466 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* the_end) { | |
| 467 return end(); | |
| 468 } | |
| 469 | |
| 470 // Requires "allowed_deadspace_words > 0", that "q" is the start of a | |
| 471 // free block of the given "word_len", and that "q", were it an object, | |
| 472 // would not move if forwared. If the size allows, fill the free | |
| 473 // block with an object, to prevent excessive compaction. Returns "true" | |
| 474 // iff the free region was made deadspace, and modifies | |
| 475 // "allowed_deadspace_words" to reflect the number of available deadspace | |
| 476 // words remaining after this operation. | |
| 477 bool insert_deadspace(size_t& allowed_deadspace_words, HeapWord* q, | |
| 478 size_t word_len); | |
| 479 }; | |
| 480 | |
| 481 #define SCAN_AND_FORWARD(cp,scan_limit,block_is_obj,block_size) { \ | |
| 482 /* Compute the new addresses for the live objects and store it in the mark \ | |
| 483 * Used by universe::mark_sweep_phase2() \ | |
| 484 */ \ | |
| 485 HeapWord* compact_top; /* This is where we are currently compacting to. */ \ | |
| 486 \ | |
| 487 /* We're sure to be here before any objects are compacted into this \ | |
| 488 * space, so this is a good time to initialize this: \ | |
| 489 */ \ | |
| 490 set_compaction_top(bottom()); \ | |
| 491 \ | |
| 492 if (cp->space == NULL) { \ | |
| 493 assert(cp->gen != NULL, "need a generation"); \ | |
| 494 assert(cp->threshold == NULL, "just checking"); \ | |
| 495 assert(cp->gen->first_compaction_space() == this, "just checking"); \ | |
| 496 cp->space = cp->gen->first_compaction_space(); \ | |
| 497 compact_top = cp->space->bottom(); \ | |
| 498 cp->space->set_compaction_top(compact_top); \ | |
| 499 cp->threshold = cp->space->initialize_threshold(); \ | |
| 500 } else { \ | |
| 501 compact_top = cp->space->compaction_top(); \ | |
| 502 } \ | |
| 503 \ | |
| 504 /* We allow some amount of garbage towards the bottom of the space, so \ | |
| 505 * we don't start compacting before there is a significant gain to be made.\ | |
| 506 * Occasionally, we want to ensure a full compaction, which is determined \ | |
| 507 * by the MarkSweepAlwaysCompactCount parameter. \ | |
| 508 */ \ | |
| 509 int invocations = SharedHeap::heap()->perm_gen()->stat_record()->invocations;\ | |
| 510 bool skip_dead = ((invocations % MarkSweepAlwaysCompactCount) != 0); \ | |
| 511 \ | |
| 512 size_t allowed_deadspace = 0; \ | |
| 513 if (skip_dead) { \ | |
| 438 | 514 const size_t ratio = allowed_dead_ratio(); \ |
| 0 | 515 allowed_deadspace = (capacity() * ratio / 100) / HeapWordSize; \ |
| 516 } \ | |
| 517 \ | |
| 518 HeapWord* q = bottom(); \ | |
| 519 HeapWord* t = scan_limit(); \ | |
| 520 \ | |
| 521 HeapWord* end_of_live= q; /* One byte beyond the last byte of the last \ | |
| 522 live object. */ \ | |
| 523 HeapWord* first_dead = end();/* The first dead object. */ \ | |
| 524 LiveRange* liveRange = NULL; /* The current live range, recorded in the \ | |
| 525 first header of preceding free area. */ \ | |
| 526 _first_dead = first_dead; \ | |
| 527 \ | |
| 528 const intx interval = PrefetchScanIntervalInBytes; \ | |
| 529 \ | |
| 530 while (q < t) { \ | |
| 531 assert(!block_is_obj(q) || \ | |
| 532 oop(q)->mark()->is_marked() || oop(q)->mark()->is_unlocked() || \ | |
| 533 oop(q)->mark()->has_bias_pattern(), \ | |
| 534 "these are the only valid states during a mark sweep"); \ | |
| 535 if (block_is_obj(q) && oop(q)->is_gc_marked()) { \ | |
| 536 /* prefetch beyond q */ \ | |
| 537 Prefetch::write(q, interval); \ | |
| 538 /* size_t size = oop(q)->size(); changing this for cms for perm gen */\ | |
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539 size_t size = block_size(q); \ |
| 0 | 540 compact_top = cp->space->forward(oop(q), size, cp, compact_top); \ |
| 541 q += size; \ | |
| 542 end_of_live = q; \ | |
| 543 } else { \ | |
| 544 /* run over all the contiguous dead objects */ \ | |
| 545 HeapWord* end = q; \ | |
| 546 do { \ | |
| 547 /* prefetch beyond end */ \ | |
| 548 Prefetch::write(end, interval); \ | |
| 549 end += block_size(end); \ | |
| 550 } while (end < t && (!block_is_obj(end) || !oop(end)->is_gc_marked()));\ | |
| 551 \ | |
| 552 /* see if we might want to pretend this object is alive so that \ | |
| 553 * we don't have to compact quite as often. \ | |
| 554 */ \ | |
| 555 if (allowed_deadspace > 0 && q == compact_top) { \ | |
| 556 size_t sz = pointer_delta(end, q); \ | |
| 557 if (insert_deadspace(allowed_deadspace, q, sz)) { \ | |
| 558 compact_top = cp->space->forward(oop(q), sz, cp, compact_top); \ | |
| 559 q = end; \ | |
| 560 end_of_live = end; \ | |
| 561 continue; \ | |
| 562 } \ | |
| 563 } \ | |
| 564 \ | |
| 565 /* otherwise, it really is a free region. */ \ | |
| 566 \ | |
| 567 /* for the previous LiveRange, record the end of the live objects. */ \ | |
| 568 if (liveRange) { \ | |
| 569 liveRange->set_end(q); \ | |
| 570 } \ | |
| 571 \ | |
| 572 /* record the current LiveRange object. \ | |
| 573 * liveRange->start() is overlaid on the mark word. \ | |
| 574 */ \ | |
| 575 liveRange = (LiveRange*)q; \ | |
| 576 liveRange->set_start(end); \ | |
| 577 liveRange->set_end(end); \ | |
| 578 \ | |
| 579 /* see if this is the first dead region. */ \ | |
| 580 if (q < first_dead) { \ | |
| 581 first_dead = q; \ | |
| 582 } \ | |
| 583 \ | |
| 584 /* move on to the next object */ \ | |
| 585 q = end; \ | |
| 586 } \ | |
| 587 } \ | |
| 588 \ | |
| 589 assert(q == t, "just checking"); \ | |
| 590 if (liveRange != NULL) { \ | |
| 591 liveRange->set_end(q); \ | |
| 592 } \ | |
| 593 _end_of_live = end_of_live; \ | |
| 594 if (end_of_live < first_dead) { \ | |
| 595 first_dead = end_of_live; \ | |
| 596 } \ | |
| 597 _first_dead = first_dead; \ | |
| 598 \ | |
| 599 /* save the compaction_top of the compaction space. */ \ | |
| 600 cp->space->set_compaction_top(compact_top); \ | |
| 601 } | |
| 602 | |
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603 #define SCAN_AND_ADJUST_POINTERS(adjust_obj_size) { \ |
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604 /* adjust all the interior pointers to point at the new locations of objects \ |
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605 * Used by MarkSweep::mark_sweep_phase3() */ \ |
| 0 | 606 \ |
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607 HeapWord* q = bottom(); \ |
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608 HeapWord* t = _end_of_live; /* Established by "prepare_for_compaction". */ \ |
| 0 | 609 \ |
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610 assert(_first_dead <= _end_of_live, "Stands to reason, no?"); \ |
| 0 | 611 \ |
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612 if (q < t && _first_dead > q && \ |
| 0 | 613 !oop(q)->is_gc_marked()) { \ |
| 614 /* we have a chunk of the space which hasn't moved and we've \ | |
| 615 * reinitialized the mark word during the previous pass, so we can't \ | |
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616 * use is_gc_marked for the traversal. */ \ |
| 0 | 617 HeapWord* end = _first_dead; \ |
| 618 \ | |
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619 while (q < end) { \ |
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620 /* I originally tried to conjoin "block_start(q) == q" to the \ |
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621 * assertion below, but that doesn't work, because you can't \ |
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622 * accurately traverse previous objects to get to the current one \ |
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623 * after their pointers (including pointers into permGen) have been \ |
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624 * updated, until the actual compaction is done. dld, 4/00 */ \ |
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625 assert(block_is_obj(q), \ |
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626 "should be at block boundaries, and should be looking at objs"); \ |
| 0 | 627 \ |
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628 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::track_interior_pointers(oop(q))); \ |
| 0 | 629 \ |
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630 /* point all the oops to the new location */ \ |
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631 size_t size = oop(q)->adjust_pointers(); \ |
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632 size = adjust_obj_size(size); \ |
| 0 | 633 \ |
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634 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::check_interior_pointers()); \ |
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635 \ |
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636 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::validate_live_oop(oop(q), size)); \ |
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637 \ |
| 0 | 638 q += size; \ |
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639 } \ |
| 0 | 640 \ |
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641 if (_first_dead == t) { \ |
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642 q = t; \ |
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643 } else { \ |
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644 /* $$$ This is funky. Using this to read the previously written \ |
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645 * LiveRange. See also use below. */ \ |
| 0 | 646 q = (HeapWord*)oop(_first_dead)->mark()->decode_pointer(); \ |
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647 } \ |
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648 } \ |
| 0 | 649 \ |
| 650 const intx interval = PrefetchScanIntervalInBytes; \ | |
| 651 \ | |
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652 debug_only(HeapWord* prev_q = NULL); \ |
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653 while (q < t) { \ |
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654 /* prefetch beyond q */ \ |
| 0 | 655 Prefetch::write(q, interval); \ |
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656 if (oop(q)->is_gc_marked()) { \ |
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657 /* q is alive */ \ |
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658 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::track_interior_pointers(oop(q))); \ |
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659 /* point all the oops to the new location */ \ |
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660 size_t size = oop(q)->adjust_pointers(); \ |
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661 size = adjust_obj_size(size); \ |
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662 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::check_interior_pointers()); \ |
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663 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::validate_live_oop(oop(q), size)); \ |
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664 debug_only(prev_q = q); \ |
| 0 | 665 q += size; \ |
| 356 | 666 } else { \ |
| 667 /* q is not a live object, so its mark should point at the next \ | |
| 668 * live object */ \ | |
| 669 debug_only(prev_q = q); \ | |
| 670 q = (HeapWord*) oop(q)->mark()->decode_pointer(); \ | |
| 671 assert(q > prev_q, "we should be moving forward through memory"); \ | |
| 672 } \ | |
| 673 } \ | |
| 0 | 674 \ |
| 356 | 675 assert(q == t, "just checking"); \ |
| 0 | 676 } |
| 677 | |
| 356 | 678 #define SCAN_AND_COMPACT(obj_size) { \ |
| 0 | 679 /* Copy all live objects to their new location \ |
| 356 | 680 * Used by MarkSweep::mark_sweep_phase4() */ \ |
| 0 | 681 \ |
| 356 | 682 HeapWord* q = bottom(); \ |
| 683 HeapWord* const t = _end_of_live; \ | |
| 684 debug_only(HeapWord* prev_q = NULL); \ | |
| 0 | 685 \ |
| 356 | 686 if (q < t && _first_dead > q && \ |
| 0 | 687 !oop(q)->is_gc_marked()) { \ |
| 356 | 688 debug_only( \ |
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689 /* we have a chunk of the space which hasn't moved and we've reinitialized \ |
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690 * the mark word during the previous pass, so we can't use is_gc_marked for \ |
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691 * the traversal. */ \ |
| 356 | 692 HeapWord* const end = _first_dead; \ |
| 693 \ | |
| 694 while (q < end) { \ | |
| 0 | 695 size_t size = obj_size(q); \ |
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696 assert(!oop(q)->is_gc_marked(), \ |
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697 "should be unmarked (special dense prefix handling)"); \ |
| 356 | 698 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::live_oop_moved_to(q, size, q)); \ |
| 699 debug_only(prev_q = q); \ | |
| 0 | 700 q += size; \ |
| 356 | 701 } \ |
| 702 ) /* debug_only */ \ | |
| 703 \ | |
| 704 if (_first_dead == t) { \ | |
| 705 q = t; \ | |
| 706 } else { \ | |
| 707 /* $$$ Funky */ \ | |
| 708 q = (HeapWord*) oop(_first_dead)->mark()->decode_pointer(); \ | |
| 709 } \ | |
| 710 } \ | |
| 0 | 711 \ |
| 356 | 712 const intx scan_interval = PrefetchScanIntervalInBytes; \ |
| 713 const intx copy_interval = PrefetchCopyIntervalInBytes; \ | |
| 714 while (q < t) { \ | |
| 715 if (!oop(q)->is_gc_marked()) { \ | |
| 716 /* mark is pointer to next marked oop */ \ | |
| 717 debug_only(prev_q = q); \ | |
| 718 q = (HeapWord*) oop(q)->mark()->decode_pointer(); \ | |
| 719 assert(q > prev_q, "we should be moving forward through memory"); \ | |
| 720 } else { \ | |
| 721 /* prefetch beyond q */ \ | |
| 0 | 722 Prefetch::read(q, scan_interval); \ |
| 723 \ | |
| 724 /* size and destination */ \ | |
| 725 size_t size = obj_size(q); \ | |
| 726 HeapWord* compaction_top = (HeapWord*)oop(q)->forwardee(); \ | |
| 727 \ | |
| 356 | 728 /* prefetch beyond compaction_top */ \ |
| 0 | 729 Prefetch::write(compaction_top, copy_interval); \ |
| 730 \ | |
| 356 | 731 /* copy object and reinit its mark */ \ |
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732 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::live_oop_moved_to(q, size, \ |
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733 compaction_top)); \ |
| 356 | 734 assert(q != compaction_top, "everything in this pass should be moving"); \ |
| 735 Copy::aligned_conjoint_words(q, compaction_top, size); \ | |
| 736 oop(compaction_top)->init_mark(); \ | |
| 737 assert(oop(compaction_top)->klass() != NULL, "should have a class"); \ | |
| 0 | 738 \ |
| 356 | 739 debug_only(prev_q = q); \ |
| 0 | 740 q += size; \ |
| 356 | 741 } \ |
| 742 } \ | |
| 0 | 743 \ |
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744 /* Let's remember if we were empty before we did the compaction. */ \ |
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745 bool was_empty = used_region().is_empty(); \ |
| 0 | 746 /* Reset space after compaction is complete */ \ |
| 356 | 747 reset_after_compaction(); \ |
| 0 | 748 /* We do this clear, below, since it has overloaded meanings for some */ \ |
| 749 /* space subtypes. For example, OffsetTableContigSpace's that were */ \ | |
| 750 /* compacted into will have had their offset table thresholds updated */ \ | |
| 751 /* continuously, but those that weren't need to have their thresholds */ \ | |
| 752 /* re-initialized. Also mangles unused area for debugging. */ \ | |
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753 if (used_region().is_empty()) { \ |
| 356 | 754 if (!was_empty) clear(SpaceDecorator::Mangle); \ |
| 0 | 755 } else { \ |
| 756 if (ZapUnusedHeapArea) mangle_unused_area(); \ | |
| 757 } \ | |
| 758 } | |
| 759 | |
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760 class GenSpaceMangler; |
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761 |
| 0 | 762 // A space in which the free area is contiguous. It therefore supports |
| 763 // faster allocation, and compaction. | |
| 764 class ContiguousSpace: public CompactibleSpace { | |
| 765 friend class OneContigSpaceCardGeneration; | |
| 766 friend class VMStructs; | |
| 767 protected: | |
| 768 HeapWord* _top; | |
| 769 HeapWord* _concurrent_iteration_safe_limit; | |
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770 // A helper for mangling the unused area of the space in debug builds. |
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771 GenSpaceMangler* _mangler; |
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772 |
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773 GenSpaceMangler* mangler() { return _mangler; } |
| 0 | 774 |
| 775 // Allocation helpers (return NULL if full). | |
| 776 inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value); | |
| 777 inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value); | |
| 778 | |
| 779 public: | |
|
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780 ContiguousSpace(); |
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781 ~ContiguousSpace(); |
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782 |
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783 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); |
| 356 | 784 virtual void clear(bool mangle_space); |
| 0 | 785 |
| 786 // Accessors | |
| 787 HeapWord* top() const { return _top; } | |
| 788 void set_top(HeapWord* value) { _top = value; } | |
| 789 | |
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790 virtual void set_saved_mark() { _saved_mark_word = top(); } |
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791 void reset_saved_mark() { _saved_mark_word = bottom(); } |
| 0 | 792 |
| 793 WaterMark bottom_mark() { return WaterMark(this, bottom()); } | |
| 794 WaterMark top_mark() { return WaterMark(this, top()); } | |
| 795 WaterMark saved_mark() { return WaterMark(this, saved_mark_word()); } | |
| 796 bool saved_mark_at_top() const { return saved_mark_word() == top(); } | |
| 797 | |
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798 // In debug mode mangle (write it with a particular bit |
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799 // pattern) the unused part of a space. |
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800 |
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801 // Used to save the an address in a space for later use during mangling. |
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802 void set_top_for_allocations(HeapWord* v) PRODUCT_RETURN; |
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803 // Used to save the space's current top for later use during mangling. |
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804 void set_top_for_allocations() PRODUCT_RETURN; |
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805 |
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806 // Mangle regions in the space from the current top up to the |
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807 // previously mangled part of the space. |
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808 void mangle_unused_area() PRODUCT_RETURN; |
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809 // Mangle [top, end) |
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810 void mangle_unused_area_complete() PRODUCT_RETURN; |
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811 // Mangle the given MemRegion. |
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812 void mangle_region(MemRegion mr) PRODUCT_RETURN; |
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813 |
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814 // Do some sparse checking on the area that should have been mangled. |
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815 void check_mangled_unused_area(HeapWord* limit) PRODUCT_RETURN; |
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816 // Check the complete area that should have been mangled. |
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817 // This code may be NULL depending on the macro DEBUG_MANGLING. |
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818 void check_mangled_unused_area_complete() PRODUCT_RETURN; |
| 0 | 819 |
| 820 // Size computations: sizes in bytes. | |
| 821 size_t capacity() const { return byte_size(bottom(), end()); } | |
| 822 size_t used() const { return byte_size(bottom(), top()); } | |
| 823 size_t free() const { return byte_size(top(), end()); } | |
| 824 | |
| 825 // Override from space. | |
| 826 bool is_in(const void* p) const; | |
| 827 | |
| 828 virtual bool is_free_block(const HeapWord* p) const; | |
| 829 | |
| 830 // In a contiguous space we have a more obvious bound on what parts | |
| 831 // contain objects. | |
| 832 MemRegion used_region() const { return MemRegion(bottom(), top()); } | |
| 833 | |
| 834 MemRegion used_region_at_save_marks() const { | |
| 835 return MemRegion(bottom(), saved_mark_word()); | |
| 836 } | |
| 837 | |
| 838 // Allocation (return NULL if full) | |
| 839 virtual HeapWord* allocate(size_t word_size); | |
| 840 virtual HeapWord* par_allocate(size_t word_size); | |
| 841 | |
| 842 virtual bool obj_allocated_since_save_marks(const oop obj) const { | |
| 843 return (HeapWord*)obj >= saved_mark_word(); | |
| 844 } | |
| 845 | |
| 846 // Iteration | |
| 847 void oop_iterate(OopClosure* cl); | |
| 848 void oop_iterate(MemRegion mr, OopClosure* cl); | |
| 849 void object_iterate(ObjectClosure* blk); | |
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850 // For contiguous spaces this method will iterate safely over objects |
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851 // in the space (i.e., between bottom and top) when at a safepoint. |
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852 void safe_object_iterate(ObjectClosure* blk); |
| 0 | 853 void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl); |
| 854 // iterates on objects up to the safe limit | |
| 855 HeapWord* object_iterate_careful(ObjectClosureCareful* cl); | |
| 856 inline HeapWord* concurrent_iteration_safe_limit(); | |
| 857 // changes the safe limit, all objects from bottom() to the new | |
| 858 // limit should be properly initialized | |
| 859 inline void set_concurrent_iteration_safe_limit(HeapWord* new_limit); | |
| 860 | |
| 861 #ifndef SERIALGC | |
| 862 // In support of parallel oop_iterate. | |
| 863 #define ContigSpace_PAR_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ | |
| 864 void par_oop_iterate(MemRegion mr, OopClosureType* blk); | |
| 865 | |
| 866 ALL_PAR_OOP_ITERATE_CLOSURES(ContigSpace_PAR_OOP_ITERATE_DECL) | |
| 867 #undef ContigSpace_PAR_OOP_ITERATE_DECL | |
| 868 #endif // SERIALGC | |
| 869 | |
| 870 // Compaction support | |
| 871 virtual void reset_after_compaction() { | |
| 872 assert(compaction_top() >= bottom() && compaction_top() <= end(), "should point inside space"); | |
| 873 set_top(compaction_top()); | |
| 874 // set new iteration safe limit | |
| 875 set_concurrent_iteration_safe_limit(compaction_top()); | |
| 876 } | |
| 877 virtual size_t minimum_free_block_size() const { return 0; } | |
| 878 | |
| 879 // Override. | |
| 880 DirtyCardToOopClosure* new_dcto_cl(OopClosure* cl, | |
| 881 CardTableModRefBS::PrecisionStyle precision, | |
| 882 HeapWord* boundary = NULL); | |
| 883 | |
| 884 // Apply "blk->do_oop" to the addresses of all reference fields in objects | |
| 885 // starting with the _saved_mark_word, which was noted during a generation's | |
| 886 // save_marks and is required to denote the head of an object. | |
| 887 // Fields in objects allocated by applications of the closure | |
| 888 // *are* included in the iteration. | |
| 889 // Updates _saved_mark_word to point to just after the last object | |
| 890 // iterated over. | |
| 891 #define ContigSpace_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ | |
| 892 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk); | |
| 893 | |
| 894 ALL_SINCE_SAVE_MARKS_CLOSURES(ContigSpace_OOP_SINCE_SAVE_MARKS_DECL) | |
| 895 #undef ContigSpace_OOP_SINCE_SAVE_MARKS_DECL | |
| 896 | |
| 897 // Same as object_iterate, but starting from "mark", which is required | |
| 898 // to denote the start of an object. Objects allocated by | |
| 899 // applications of the closure *are* included in the iteration. | |
| 900 virtual void object_iterate_from(WaterMark mark, ObjectClosure* blk); | |
| 901 | |
| 902 // Very inefficient implementation. | |
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903 virtual HeapWord* block_start_const(const void* p) const; |
| 0 | 904 size_t block_size(const HeapWord* p) const; |
| 905 // If a block is in the allocated area, it is an object. | |
| 906 bool block_is_obj(const HeapWord* p) const { return p < top(); } | |
| 907 | |
| 908 // Addresses for inlined allocation | |
| 909 HeapWord** top_addr() { return &_top; } | |
| 910 HeapWord** end_addr() { return &_end; } | |
| 911 | |
| 912 // Overrides for more efficient compaction support. | |
| 913 void prepare_for_compaction(CompactPoint* cp); | |
| 914 | |
| 915 // PrintHeapAtGC support. | |
| 916 virtual void print_on(outputStream* st) const; | |
| 917 | |
| 918 // Checked dynamic downcasts. | |
| 919 virtual ContiguousSpace* toContiguousSpace() { | |
| 920 return this; | |
| 921 } | |
| 922 | |
| 923 // Debugging | |
| 924 virtual void verify(bool allow_dirty) const; | |
| 925 | |
| 926 // Used to increase collection frequency. "factor" of 0 means entire | |
| 927 // space. | |
| 928 void allocate_temporary_filler(int factor); | |
| 929 | |
| 930 }; | |
| 931 | |
| 932 | |
| 933 // A dirty card to oop closure that does filtering. | |
| 934 // It knows how to filter out objects that are outside of the _boundary. | |
| 935 class Filtering_DCTOC : public DirtyCardToOopClosure { | |
| 936 protected: | |
| 937 // Override. | |
| 938 void walk_mem_region(MemRegion mr, | |
| 939 HeapWord* bottom, HeapWord* top); | |
| 940 | |
| 941 // Walk the given memory region, from bottom to top, applying | |
| 942 // the given oop closure to (possibly) all objects found. The | |
| 943 // given oop closure may or may not be the same as the oop | |
| 944 // closure with which this closure was created, as it may | |
| 945 // be a filtering closure which makes use of the _boundary. | |
| 946 // We offer two signatures, so the FilteringClosure static type is | |
| 947 // apparent. | |
| 948 virtual void walk_mem_region_with_cl(MemRegion mr, | |
| 949 HeapWord* bottom, HeapWord* top, | |
| 950 OopClosure* cl) = 0; | |
| 951 virtual void walk_mem_region_with_cl(MemRegion mr, | |
| 952 HeapWord* bottom, HeapWord* top, | |
| 953 FilteringClosure* cl) = 0; | |
| 954 | |
| 955 public: | |
| 956 Filtering_DCTOC(Space* sp, OopClosure* cl, | |
| 957 CardTableModRefBS::PrecisionStyle precision, | |
| 958 HeapWord* boundary) : | |
| 959 DirtyCardToOopClosure(sp, cl, precision, boundary) {} | |
| 960 }; | |
| 961 | |
| 962 // A dirty card to oop closure for contiguous spaces | |
| 963 // (ContiguousSpace and sub-classes). | |
| 964 // It is a FilteringClosure, as defined above, and it knows: | |
| 965 // | |
| 966 // 1. That the actual top of any area in a memory region | |
| 967 // contained by the space is bounded by the end of the contiguous | |
| 968 // region of the space. | |
| 969 // 2. That the space is really made up of objects and not just | |
| 970 // blocks. | |
| 971 | |
| 972 class ContiguousSpaceDCTOC : public Filtering_DCTOC { | |
| 973 protected: | |
| 974 // Overrides. | |
| 975 HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj); | |
| 976 | |
| 977 virtual void walk_mem_region_with_cl(MemRegion mr, | |
| 978 HeapWord* bottom, HeapWord* top, | |
| 979 OopClosure* cl); | |
| 980 virtual void walk_mem_region_with_cl(MemRegion mr, | |
| 981 HeapWord* bottom, HeapWord* top, | |
| 982 FilteringClosure* cl); | |
| 983 | |
| 984 public: | |
| 985 ContiguousSpaceDCTOC(ContiguousSpace* sp, OopClosure* cl, | |
| 986 CardTableModRefBS::PrecisionStyle precision, | |
| 987 HeapWord* boundary) : | |
| 988 Filtering_DCTOC(sp, cl, precision, boundary) | |
| 989 {} | |
| 990 }; | |
| 991 | |
| 992 | |
| 993 // Class EdenSpace describes eden-space in new generation. | |
| 994 | |
| 995 class DefNewGeneration; | |
| 996 | |
| 997 class EdenSpace : public ContiguousSpace { | |
| 998 friend class VMStructs; | |
| 999 private: | |
| 1000 DefNewGeneration* _gen; | |
| 1001 | |
| 1002 // _soft_end is used as a soft limit on allocation. As soft limits are | |
| 1003 // reached, the slow-path allocation code can invoke other actions and then | |
| 1004 // adjust _soft_end up to a new soft limit or to end(). | |
| 1005 HeapWord* _soft_end; | |
| 1006 | |
| 1007 public: | |
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1008 EdenSpace(DefNewGeneration* gen) : |
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1009 _gen(gen), _soft_end(NULL) {} |
| 0 | 1010 |
| 1011 // Get/set just the 'soft' limit. | |
| 1012 HeapWord* soft_end() { return _soft_end; } | |
| 1013 HeapWord** soft_end_addr() { return &_soft_end; } | |
| 1014 void set_soft_end(HeapWord* value) { _soft_end = value; } | |
| 1015 | |
| 1016 // Override. | |
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1017 void clear(bool mangle_space); |
| 0 | 1018 |
| 1019 // Set both the 'hard' and 'soft' limits (_end and _soft_end). | |
| 1020 void set_end(HeapWord* value) { | |
| 1021 set_soft_end(value); | |
| 1022 ContiguousSpace::set_end(value); | |
| 1023 } | |
| 1024 | |
| 1025 // Allocation (return NULL if full) | |
| 1026 HeapWord* allocate(size_t word_size); | |
| 1027 HeapWord* par_allocate(size_t word_size); | |
| 1028 }; | |
| 1029 | |
| 1030 // Class ConcEdenSpace extends EdenSpace for the sake of safe | |
| 1031 // allocation while soft-end is being modified concurrently | |
| 1032 | |
| 1033 class ConcEdenSpace : public EdenSpace { | |
| 1034 public: | |
| 1035 ConcEdenSpace(DefNewGeneration* gen) : EdenSpace(gen) { } | |
| 1036 | |
| 1037 // Allocation (return NULL if full) | |
| 1038 HeapWord* par_allocate(size_t word_size); | |
| 1039 }; | |
| 1040 | |
| 1041 | |
| 1042 // A ContigSpace that Supports an efficient "block_start" operation via | |
| 1043 // a BlockOffsetArray (whose BlockOffsetSharedArray may be shared with | |
| 1044 // other spaces.) This is the abstract base class for old generation | |
| 1045 // (tenured, perm) spaces. | |
| 1046 | |
| 1047 class OffsetTableContigSpace: public ContiguousSpace { | |
| 1048 friend class VMStructs; | |
| 1049 protected: | |
| 1050 BlockOffsetArrayContigSpace _offsets; | |
| 1051 Mutex _par_alloc_lock; | |
| 1052 | |
| 1053 public: | |
| 1054 // Constructor | |
| 1055 OffsetTableContigSpace(BlockOffsetSharedArray* sharedOffsetArray, | |
| 1056 MemRegion mr); | |
| 1057 | |
| 1058 void set_bottom(HeapWord* value); | |
| 1059 void set_end(HeapWord* value); | |
| 1060 | |
|
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1061 void clear(bool mangle_space); |
| 0 | 1062 |
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1063 inline HeapWord* block_start_const(const void* p) const; |
| 0 | 1064 |
| 1065 // Add offset table update. | |
| 1066 virtual inline HeapWord* allocate(size_t word_size); | |
| 1067 inline HeapWord* par_allocate(size_t word_size); | |
| 1068 | |
| 1069 // MarkSweep support phase3 | |
| 1070 virtual HeapWord* initialize_threshold(); | |
| 1071 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); | |
| 1072 | |
| 1073 virtual void print_on(outputStream* st) const; | |
| 1074 | |
| 1075 // Debugging | |
| 1076 void verify(bool allow_dirty) const; | |
| 1077 | |
| 1078 // Shared space support | |
| 1079 void serialize_block_offset_array_offsets(SerializeOopClosure* soc); | |
| 1080 }; | |
| 1081 | |
| 1082 | |
| 1083 // Class TenuredSpace is used by TenuredGeneration | |
| 1084 | |
| 1085 class TenuredSpace: public OffsetTableContigSpace { | |
| 1086 friend class VMStructs; | |
| 1087 protected: | |
| 1088 // Mark sweep support | |
| 438 | 1089 size_t allowed_dead_ratio() const; |
| 0 | 1090 public: |
| 1091 // Constructor | |
| 1092 TenuredSpace(BlockOffsetSharedArray* sharedOffsetArray, | |
| 1093 MemRegion mr) : | |
| 1094 OffsetTableContigSpace(sharedOffsetArray, mr) {} | |
| 1095 }; | |
| 1096 | |
| 1097 | |
| 1098 // Class ContigPermSpace is used by CompactingPermGen | |
| 1099 | |
| 1100 class ContigPermSpace: public OffsetTableContigSpace { | |
| 1101 friend class VMStructs; | |
| 1102 protected: | |
| 1103 // Mark sweep support | |
| 438 | 1104 size_t allowed_dead_ratio() const; |
| 0 | 1105 public: |
| 1106 // Constructor | |
| 1107 ContigPermSpace(BlockOffsetSharedArray* sharedOffsetArray, MemRegion mr) : | |
| 1108 OffsetTableContigSpace(sharedOffsetArray, mr) {} | |
| 1109 }; |