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annotate src/share/vm/memory/space.hpp @ 832:e7d5557ad624
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author | jmasa |
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date | Thu, 02 Jul 2009 16:28:15 -0700 |
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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; } |
0 | 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 | |
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134 // Initialization. |
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135 // "initialize" should be called once on a space, before it is used for |
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136 // any purpose. The "mr" arguments gives the bounds of the space, and |
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137 // the "clear_space" argument should be true unless the memory in "mr" is |
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138 // known to be zeroed. |
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139 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); |
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140 |
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141 // The "clear" method must be called on a region that may have |
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142 // had allocation performed in it, but is now to be considered empty. |
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143 virtual void clear(bool mangle_space); |
0 | 144 |
145 // For detecting GC bugs. Should only be called at GC boundaries, since | |
146 // some unused space may be used as scratch space during GC's. | |
147 // Default implementation does nothing. We also call this when expanding | |
148 // a space to satisfy an allocation request. See bug #4668531 | |
149 virtual void mangle_unused_area() {} | |
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150 virtual void mangle_unused_area_complete() {} |
0 | 151 virtual void mangle_region(MemRegion mr) {} |
152 | |
153 // Testers | |
154 bool is_empty() const { return used() == 0; } | |
155 bool not_empty() const { return used() > 0; } | |
156 | |
157 // Returns true iff the given the space contains the | |
158 // given address as part of an allocated object. For | |
159 // ceratin kinds of spaces, this might be a potentially | |
160 // expensive operation. To prevent performance problems | |
161 // on account of its inadvertent use in product jvm's, | |
162 // we restrict its use to assertion checks only. | |
163 virtual bool is_in(const void* p) const; | |
164 | |
165 // Returns true iff the given reserved memory of the space contains the | |
166 // given address. | |
167 bool is_in_reserved(const void* p) const { return _bottom <= p && p < _end; } | |
168 | |
169 // Returns true iff the given block is not allocated. | |
170 virtual bool is_free_block(const HeapWord* p) const = 0; | |
171 | |
172 // Test whether p is double-aligned | |
173 static bool is_aligned(void* p) { | |
174 return ((intptr_t)p & (sizeof(double)-1)) == 0; | |
175 } | |
176 | |
177 // Size computations. Sizes are in bytes. | |
178 size_t capacity() const { return byte_size(bottom(), end()); } | |
179 virtual size_t used() const = 0; | |
180 virtual size_t free() const = 0; | |
181 | |
182 // Iterate over all the ref-containing fields of all objects in the | |
183 // space, calling "cl.do_oop" on each. Fields in objects allocated by | |
184 // applications of the closure are not included in the iteration. | |
185 virtual void oop_iterate(OopClosure* cl); | |
186 | |
187 // Same as above, restricted to the intersection of a memory region and | |
188 // the space. Fields in objects allocated by applications of the closure | |
189 // are not included in the iteration. | |
190 virtual void oop_iterate(MemRegion mr, OopClosure* cl) = 0; | |
191 | |
192 // Iterate over all objects in the space, calling "cl.do_object" on | |
193 // each. Objects allocated by applications of the closure are not | |
194 // included in the iteration. | |
195 virtual void object_iterate(ObjectClosure* blk) = 0; | |
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196 // Similar to object_iterate() except only iterates over |
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197 // objects whose internal references point to objects in the space. |
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198 virtual void safe_object_iterate(ObjectClosure* blk) = 0; |
0 | 199 |
200 // Iterate over all objects that intersect with mr, calling "cl->do_object" | |
201 // on each. There is an exception to this: if this closure has already | |
202 // been invoked on an object, it may skip such objects in some cases. This is | |
203 // Most likely to happen in an "upwards" (ascending address) iteration of | |
204 // MemRegions. | |
205 virtual void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl); | |
206 | |
207 // Iterate over as many initialized objects in the space as possible, | |
208 // calling "cl.do_object_careful" on each. Return NULL if all objects | |
209 // in the space (at the start of the iteration) were iterated over. | |
210 // Return an address indicating the extent of the iteration in the | |
211 // event that the iteration had to return because of finding an | |
212 // uninitialized object in the space, or if the closure "cl" | |
213 // signalled early termination. | |
214 virtual HeapWord* object_iterate_careful(ObjectClosureCareful* cl); | |
215 virtual HeapWord* object_iterate_careful_m(MemRegion mr, | |
216 ObjectClosureCareful* cl); | |
217 | |
218 // Create and return a new dirty card to oop closure. Can be | |
219 // overriden to return the appropriate type of closure | |
220 // depending on the type of space in which the closure will | |
221 // operate. ResourceArea allocated. | |
222 virtual DirtyCardToOopClosure* new_dcto_cl(OopClosure* cl, | |
223 CardTableModRefBS::PrecisionStyle precision, | |
224 HeapWord* boundary = NULL); | |
225 | |
226 // If "p" is in the space, returns the address of the start of the | |
227 // "block" that contains "p". We say "block" instead of "object" since | |
228 // some heaps may not pack objects densely; a chunk may either be an | |
229 // object or a non-object. If "p" is not in the space, return NULL. | |
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230 virtual HeapWord* block_start_const(const void* p) const = 0; |
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231 |
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232 // The non-const version may have benevolent side effects on the data |
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233 // structure supporting these calls, possibly speeding up future calls. |
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234 // The default implementation, however, is simply to call the const |
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235 // version. |
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236 inline virtual HeapWord* block_start(const void* p); |
0 | 237 |
238 // Requires "addr" to be the start of a chunk, and returns its size. | |
239 // "addr + size" is required to be the start of a new chunk, or the end | |
240 // of the active area of the heap. | |
241 virtual size_t block_size(const HeapWord* addr) const = 0; | |
242 | |
243 // Requires "addr" to be the start of a block, and returns "TRUE" iff | |
244 // the block is an object. | |
245 virtual bool block_is_obj(const HeapWord* addr) const = 0; | |
246 | |
247 // Requires "addr" to be the start of a block, and returns "TRUE" iff | |
248 // the block is an object and the object is alive. | |
249 virtual bool obj_is_alive(const HeapWord* addr) const; | |
250 | |
251 // Allocation (return NULL if full). Assumes the caller has established | |
252 // mutually exclusive access to the space. | |
253 virtual HeapWord* allocate(size_t word_size) = 0; | |
254 | |
255 // Allocation (return NULL if full). Enforces mutual exclusion internally. | |
256 virtual HeapWord* par_allocate(size_t word_size) = 0; | |
257 | |
258 // Returns true if this object has been allocated since a | |
259 // generation's "save_marks" call. | |
260 virtual bool obj_allocated_since_save_marks(const oop obj) const = 0; | |
261 | |
262 // Mark-sweep-compact support: all spaces can update pointers to objects | |
263 // moving as a part of compaction. | |
264 virtual void adjust_pointers(); | |
265 | |
266 // PrintHeapAtGC support | |
267 virtual void print() const; | |
268 virtual void print_on(outputStream* st) const; | |
269 virtual void print_short() const; | |
270 virtual void print_short_on(outputStream* st) const; | |
271 | |
272 | |
273 // Accessor for parallel sequential tasks. | |
274 SequentialSubTasksDone* par_seq_tasks() { return &_par_seq_tasks; } | |
275 | |
276 // IF "this" is a ContiguousSpace, return it, else return NULL. | |
277 virtual ContiguousSpace* toContiguousSpace() { | |
278 return NULL; | |
279 } | |
280 | |
281 // Debugging | |
282 virtual void verify(bool allow_dirty) const = 0; | |
283 }; | |
284 | |
285 // A MemRegionClosure (ResourceObj) whose "do_MemRegion" function applies an | |
286 // OopClosure to (the addresses of) all the ref-containing fields that could | |
287 // be modified by virtue of the given MemRegion being dirty. (Note that | |
288 // because of the imprecise nature of the write barrier, this may iterate | |
289 // over oops beyond the region.) | |
290 // This base type for dirty card to oop closures handles memory regions | |
291 // in non-contiguous spaces with no boundaries, and should be sub-classed | |
292 // to support other space types. See ContiguousDCTOC for a sub-class | |
293 // that works with ContiguousSpaces. | |
294 | |
295 class DirtyCardToOopClosure: public MemRegionClosureRO { | |
296 protected: | |
297 OopClosure* _cl; | |
298 Space* _sp; | |
299 CardTableModRefBS::PrecisionStyle _precision; | |
300 HeapWord* _boundary; // If non-NULL, process only non-NULL oops | |
301 // pointing below boundary. | |
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302 HeapWord* _min_done; // ObjHeadPreciseArray precision requires |
0 | 303 // a downwards traversal; this is the |
304 // lowest location already done (or, | |
305 // alternatively, the lowest address that | |
306 // shouldn't be done again. NULL means infinity.) | |
307 NOT_PRODUCT(HeapWord* _last_bottom;) | |
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308 NOT_PRODUCT(HeapWord* _last_explicit_min_done;) |
0 | 309 |
310 // Get the actual top of the area on which the closure will | |
311 // operate, given where the top is assumed to be (the end of the | |
312 // memory region passed to do_MemRegion) and where the object | |
313 // at the top is assumed to start. For example, an object may | |
314 // start at the top but actually extend past the assumed top, | |
315 // in which case the top becomes the end of the object. | |
316 virtual HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj); | |
317 | |
318 // Walk the given memory region from bottom to (actual) top | |
319 // looking for objects and applying the oop closure (_cl) to | |
320 // them. The base implementation of this treats the area as | |
321 // blocks, where a block may or may not be an object. Sub- | |
322 // classes should override this to provide more accurate | |
323 // or possibly more efficient walking. | |
324 virtual void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top); | |
325 | |
326 public: | |
327 DirtyCardToOopClosure(Space* sp, OopClosure* cl, | |
328 CardTableModRefBS::PrecisionStyle precision, | |
329 HeapWord* boundary) : | |
330 _sp(sp), _cl(cl), _precision(precision), _boundary(boundary), | |
331 _min_done(NULL) { | |
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332 NOT_PRODUCT(_last_bottom = NULL); |
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333 NOT_PRODUCT(_last_explicit_min_done = NULL); |
0 | 334 } |
335 | |
336 void do_MemRegion(MemRegion mr); | |
337 | |
338 void set_min_done(HeapWord* min_done) { | |
339 _min_done = min_done; | |
342
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340 NOT_PRODUCT(_last_explicit_min_done = _min_done); |
0 | 341 } |
342 #ifndef PRODUCT | |
343 void set_last_bottom(HeapWord* last_bottom) { | |
344 _last_bottom = last_bottom; | |
345 } | |
346 #endif | |
347 }; | |
348 | |
349 // A structure to represent a point at which objects are being copied | |
350 // during compaction. | |
351 class CompactPoint : public StackObj { | |
352 public: | |
353 Generation* gen; | |
354 CompactibleSpace* space; | |
355 HeapWord* threshold; | |
356 CompactPoint(Generation* _gen, CompactibleSpace* _space, | |
357 HeapWord* _threshold) : | |
358 gen(_gen), space(_space), threshold(_threshold) {} | |
359 }; | |
360 | |
361 | |
362 // A space that supports compaction operations. This is usually, but not | |
363 // necessarily, a space that is normally contiguous. But, for example, a | |
364 // free-list-based space whose normal collection is a mark-sweep without | |
365 // compaction could still support compaction in full GC's. | |
366 | |
367 class CompactibleSpace: public Space { | |
368 friend class VMStructs; | |
369 friend class CompactibleFreeListSpace; | |
370 friend class CompactingPermGenGen; | |
371 friend class CMSPermGenGen; | |
372 private: | |
373 HeapWord* _compaction_top; | |
374 CompactibleSpace* _next_compaction_space; | |
375 | |
376 public: | |
347
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377 CompactibleSpace() : |
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378 _compaction_top(NULL), _next_compaction_space(NULL) {} |
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379 |
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380 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); |
356 | 381 virtual void clear(bool mangle_space); |
0 | 382 |
383 // Used temporarily during a compaction phase to hold the value | |
384 // top should have when compaction is complete. | |
385 HeapWord* compaction_top() const { return _compaction_top; } | |
386 | |
387 void set_compaction_top(HeapWord* value) { | |
388 assert(value == NULL || (value >= bottom() && value <= end()), | |
389 "should point inside space"); | |
390 _compaction_top = value; | |
391 } | |
392 | |
393 // Perform operations on the space needed after a compaction | |
394 // has been performed. | |
395 virtual void reset_after_compaction() {} | |
396 | |
397 // Returns the next space (in the current generation) to be compacted in | |
398 // the global compaction order. Also is used to select the next | |
399 // space into which to compact. | |
400 | |
401 virtual CompactibleSpace* next_compaction_space() const { | |
402 return _next_compaction_space; | |
403 } | |
404 | |
405 void set_next_compaction_space(CompactibleSpace* csp) { | |
406 _next_compaction_space = csp; | |
407 } | |
408 | |
409 // MarkSweep support phase2 | |
410 | |
411 // Start the process of compaction of the current space: compute | |
412 // post-compaction addresses, and insert forwarding pointers. The fields | |
413 // "cp->gen" and "cp->compaction_space" are the generation and space into | |
414 // which we are currently compacting. This call updates "cp" as necessary, | |
415 // and leaves the "compaction_top" of the final value of | |
416 // "cp->compaction_space" up-to-date. Offset tables may be updated in | |
417 // this phase as if the final copy had occurred; if so, "cp->threshold" | |
418 // indicates when the next such action should be taken. | |
419 virtual void prepare_for_compaction(CompactPoint* cp); | |
420 // MarkSweep support phase3 | |
421 virtual void adjust_pointers(); | |
422 // MarkSweep support phase4 | |
423 virtual void compact(); | |
424 | |
425 // The maximum percentage of objects that can be dead in the compacted | |
426 // live part of a compacted space ("deadwood" support.) | |
438 | 427 virtual size_t allowed_dead_ratio() const { return 0; }; |
0 | 428 |
429 // Some contiguous spaces may maintain some data structures that should | |
430 // be updated whenever an allocation crosses a boundary. This function | |
431 // returns the first such boundary. | |
432 // (The default implementation returns the end of the space, so the | |
433 // boundary is never crossed.) | |
434 virtual HeapWord* initialize_threshold() { return end(); } | |
435 | |
436 // "q" is an object of the given "size" that should be forwarded; | |
437 // "cp" names the generation ("gen") and containing "this" (which must | |
438 // also equal "cp->space"). "compact_top" is where in "this" the | |
439 // next object should be forwarded to. If there is room in "this" for | |
440 // the object, insert an appropriate forwarding pointer in "q". | |
441 // If not, go to the next compaction space (there must | |
442 // be one, since compaction must succeed -- we go to the first space of | |
443 // the previous generation if necessary, updating "cp"), reset compact_top | |
444 // and then forward. In either case, returns the new value of "compact_top". | |
445 // If the forwarding crosses "cp->threshold", invokes the "cross_threhold" | |
446 // function of the then-current compaction space, and updates "cp->threshold | |
447 // accordingly". | |
448 virtual HeapWord* forward(oop q, size_t size, CompactPoint* cp, | |
449 HeapWord* compact_top); | |
450 | |
451 // Return a size with adjusments as required of the space. | |
452 virtual size_t adjust_object_size_v(size_t size) const { return size; } | |
453 | |
454 protected: | |
455 // Used during compaction. | |
456 HeapWord* _first_dead; | |
457 HeapWord* _end_of_live; | |
458 | |
459 // Minimum size of a free block. | |
460 virtual size_t minimum_free_block_size() const = 0; | |
461 | |
462 // This the function is invoked when an allocation of an object covering | |
463 // "start" to "end occurs crosses the threshold; returns the next | |
464 // threshold. (The default implementation does nothing.) | |
465 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* the_end) { | |
466 return end(); | |
467 } | |
468 | |
469 // Requires "allowed_deadspace_words > 0", that "q" is the start of a | |
470 // free block of the given "word_len", and that "q", were it an object, | |
471 // would not move if forwared. If the size allows, fill the free | |
472 // block with an object, to prevent excessive compaction. Returns "true" | |
473 // iff the free region was made deadspace, and modifies | |
474 // "allowed_deadspace_words" to reflect the number of available deadspace | |
475 // words remaining after this operation. | |
476 bool insert_deadspace(size_t& allowed_deadspace_words, HeapWord* q, | |
477 size_t word_len); | |
478 }; | |
479 | |
480 #define SCAN_AND_FORWARD(cp,scan_limit,block_is_obj,block_size) { \ | |
481 /* Compute the new addresses for the live objects and store it in the mark \ | |
482 * Used by universe::mark_sweep_phase2() \ | |
483 */ \ | |
484 HeapWord* compact_top; /* This is where we are currently compacting to. */ \ | |
485 \ | |
486 /* We're sure to be here before any objects are compacted into this \ | |
487 * space, so this is a good time to initialize this: \ | |
488 */ \ | |
489 set_compaction_top(bottom()); \ | |
490 \ | |
491 if (cp->space == NULL) { \ | |
492 assert(cp->gen != NULL, "need a generation"); \ | |
493 assert(cp->threshold == NULL, "just checking"); \ | |
494 assert(cp->gen->first_compaction_space() == this, "just checking"); \ | |
495 cp->space = cp->gen->first_compaction_space(); \ | |
496 compact_top = cp->space->bottom(); \ | |
497 cp->space->set_compaction_top(compact_top); \ | |
498 cp->threshold = cp->space->initialize_threshold(); \ | |
499 } else { \ | |
500 compact_top = cp->space->compaction_top(); \ | |
501 } \ | |
502 \ | |
503 /* We allow some amount of garbage towards the bottom of the space, so \ | |
504 * we don't start compacting before there is a significant gain to be made.\ | |
505 * Occasionally, we want to ensure a full compaction, which is determined \ | |
506 * by the MarkSweepAlwaysCompactCount parameter. \ | |
507 */ \ | |
508 int invocations = SharedHeap::heap()->perm_gen()->stat_record()->invocations;\ | |
509 bool skip_dead = ((invocations % MarkSweepAlwaysCompactCount) != 0); \ | |
510 \ | |
511 size_t allowed_deadspace = 0; \ | |
512 if (skip_dead) { \ | |
438 | 513 const size_t ratio = allowed_dead_ratio(); \ |
0 | 514 allowed_deadspace = (capacity() * ratio / 100) / HeapWordSize; \ |
515 } \ | |
516 \ | |
517 HeapWord* q = bottom(); \ | |
518 HeapWord* t = scan_limit(); \ | |
519 \ | |
520 HeapWord* end_of_live= q; /* One byte beyond the last byte of the last \ | |
521 live object. */ \ | |
522 HeapWord* first_dead = end();/* The first dead object. */ \ | |
523 LiveRange* liveRange = NULL; /* The current live range, recorded in the \ | |
524 first header of preceding free area. */ \ | |
525 _first_dead = first_dead; \ | |
526 \ | |
527 const intx interval = PrefetchScanIntervalInBytes; \ | |
528 \ | |
529 while (q < t) { \ | |
530 assert(!block_is_obj(q) || \ | |
531 oop(q)->mark()->is_marked() || oop(q)->mark()->is_unlocked() || \ | |
532 oop(q)->mark()->has_bias_pattern(), \ | |
533 "these are the only valid states during a mark sweep"); \ | |
534 if (block_is_obj(q) && oop(q)->is_gc_marked()) { \ | |
535 /* prefetch beyond q */ \ | |
536 Prefetch::write(q, interval); \ | |
537 /* size_t size = oop(q)->size(); changing this for cms for perm gen */\ | |
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538 size_t size = block_size(q); \ |
0 | 539 compact_top = cp->space->forward(oop(q), size, cp, compact_top); \ |
540 q += size; \ | |
541 end_of_live = q; \ | |
542 } else { \ | |
543 /* run over all the contiguous dead objects */ \ | |
544 HeapWord* end = q; \ | |
545 do { \ | |
546 /* prefetch beyond end */ \ | |
547 Prefetch::write(end, interval); \ | |
548 end += block_size(end); \ | |
549 } while (end < t && (!block_is_obj(end) || !oop(end)->is_gc_marked()));\ | |
550 \ | |
551 /* see if we might want to pretend this object is alive so that \ | |
552 * we don't have to compact quite as often. \ | |
553 */ \ | |
554 if (allowed_deadspace > 0 && q == compact_top) { \ | |
555 size_t sz = pointer_delta(end, q); \ | |
556 if (insert_deadspace(allowed_deadspace, q, sz)) { \ | |
557 compact_top = cp->space->forward(oop(q), sz, cp, compact_top); \ | |
558 q = end; \ | |
559 end_of_live = end; \ | |
560 continue; \ | |
561 } \ | |
562 } \ | |
563 \ | |
564 /* otherwise, it really is a free region. */ \ | |
565 \ | |
566 /* for the previous LiveRange, record the end of the live objects. */ \ | |
567 if (liveRange) { \ | |
568 liveRange->set_end(q); \ | |
569 } \ | |
570 \ | |
571 /* record the current LiveRange object. \ | |
572 * liveRange->start() is overlaid on the mark word. \ | |
573 */ \ | |
574 liveRange = (LiveRange*)q; \ | |
575 liveRange->set_start(end); \ | |
576 liveRange->set_end(end); \ | |
577 \ | |
578 /* see if this is the first dead region. */ \ | |
579 if (q < first_dead) { \ | |
580 first_dead = q; \ | |
581 } \ | |
582 \ | |
583 /* move on to the next object */ \ | |
584 q = end; \ | |
585 } \ | |
586 } \ | |
587 \ | |
588 assert(q == t, "just checking"); \ | |
589 if (liveRange != NULL) { \ | |
590 liveRange->set_end(q); \ | |
591 } \ | |
592 _end_of_live = end_of_live; \ | |
593 if (end_of_live < first_dead) { \ | |
594 first_dead = end_of_live; \ | |
595 } \ | |
596 _first_dead = first_dead; \ | |
597 \ | |
598 /* save the compaction_top of the compaction space. */ \ | |
599 cp->space->set_compaction_top(compact_top); \ | |
600 } | |
601 | |
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602 #define SCAN_AND_ADJUST_POINTERS(adjust_obj_size) { \ |
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603 /* adjust all the interior pointers to point at the new locations of objects \ |
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604 * Used by MarkSweep::mark_sweep_phase3() */ \ |
0 | 605 \ |
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606 HeapWord* q = bottom(); \ |
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607 HeapWord* t = _end_of_live; /* Established by "prepare_for_compaction". */ \ |
0 | 608 \ |
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609 assert(_first_dead <= _end_of_live, "Stands to reason, no?"); \ |
0 | 610 \ |
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611 if (q < t && _first_dead > q && \ |
0 | 612 !oop(q)->is_gc_marked()) { \ |
613 /* we have a chunk of the space which hasn't moved and we've \ | |
614 * reinitialized the mark word during the previous pass, so we can't \ | |
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615 * use is_gc_marked for the traversal. */ \ |
0 | 616 HeapWord* end = _first_dead; \ |
617 \ | |
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618 while (q < end) { \ |
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619 /* I originally tried to conjoin "block_start(q) == q" to the \ |
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620 * assertion below, but that doesn't work, because you can't \ |
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621 * accurately traverse previous objects to get to the current one \ |
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622 * after their pointers (including pointers into permGen) have been \ |
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623 * updated, until the actual compaction is done. dld, 4/00 */ \ |
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624 assert(block_is_obj(q), \ |
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625 "should be at block boundaries, and should be looking at objs"); \ |
0 | 626 \ |
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627 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::track_interior_pointers(oop(q))); \ |
0 | 628 \ |
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629 /* point all the oops to the new location */ \ |
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630 size_t size = oop(q)->adjust_pointers(); \ |
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631 size = adjust_obj_size(size); \ |
0 | 632 \ |
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633 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::check_interior_pointers()); \ |
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634 \ |
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635 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::validate_live_oop(oop(q), size)); \ |
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636 \ |
0 | 637 q += size; \ |
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638 } \ |
0 | 639 \ |
342
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640 if (_first_dead == t) { \ |
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641 q = t; \ |
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642 } else { \ |
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643 /* $$$ This is funky. Using this to read the previously written \ |
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644 * LiveRange. See also use below. */ \ |
0 | 645 q = (HeapWord*)oop(_first_dead)->mark()->decode_pointer(); \ |
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646 } \ |
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647 } \ |
0 | 648 \ |
649 const intx interval = PrefetchScanIntervalInBytes; \ | |
650 \ | |
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651 debug_only(HeapWord* prev_q = NULL); \ |
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652 while (q < t) { \ |
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653 /* prefetch beyond q */ \ |
0 | 654 Prefetch::write(q, interval); \ |
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655 if (oop(q)->is_gc_marked()) { \ |
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656 /* q is alive */ \ |
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657 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::track_interior_pointers(oop(q))); \ |
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658 /* point all the oops to the new location */ \ |
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659 size_t size = oop(q)->adjust_pointers(); \ |
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660 size = adjust_obj_size(size); \ |
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661 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::check_interior_pointers()); \ |
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662 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::validate_live_oop(oop(q), size)); \ |
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663 debug_only(prev_q = q); \ |
0 | 664 q += size; \ |
356 | 665 } else { \ |
666 /* q is not a live object, so its mark should point at the next \ | |
667 * live object */ \ | |
668 debug_only(prev_q = q); \ | |
669 q = (HeapWord*) oop(q)->mark()->decode_pointer(); \ | |
670 assert(q > prev_q, "we should be moving forward through memory"); \ | |
671 } \ | |
672 } \ | |
0 | 673 \ |
356 | 674 assert(q == t, "just checking"); \ |
0 | 675 } |
676 | |
356 | 677 #define SCAN_AND_COMPACT(obj_size) { \ |
0 | 678 /* Copy all live objects to their new location \ |
356 | 679 * Used by MarkSweep::mark_sweep_phase4() */ \ |
0 | 680 \ |
356 | 681 HeapWord* q = bottom(); \ |
682 HeapWord* const t = _end_of_live; \ | |
683 debug_only(HeapWord* prev_q = NULL); \ | |
0 | 684 \ |
356 | 685 if (q < t && _first_dead > q && \ |
0 | 686 !oop(q)->is_gc_marked()) { \ |
356 | 687 debug_only( \ |
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688 /* we have a chunk of the space which hasn't moved and we've reinitialized \ |
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689 * the mark word during the previous pass, so we can't use is_gc_marked for \ |
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690 * the traversal. */ \ |
356 | 691 HeapWord* const end = _first_dead; \ |
692 \ | |
693 while (q < end) { \ | |
0 | 694 size_t size = obj_size(q); \ |
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695 assert(!oop(q)->is_gc_marked(), \ |
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696 "should be unmarked (special dense prefix handling)"); \ |
356 | 697 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::live_oop_moved_to(q, size, q)); \ |
698 debug_only(prev_q = q); \ | |
0 | 699 q += size; \ |
356 | 700 } \ |
701 ) /* debug_only */ \ | |
702 \ | |
703 if (_first_dead == t) { \ | |
704 q = t; \ | |
705 } else { \ | |
706 /* $$$ Funky */ \ | |
707 q = (HeapWord*) oop(_first_dead)->mark()->decode_pointer(); \ | |
708 } \ | |
709 } \ | |
0 | 710 \ |
356 | 711 const intx scan_interval = PrefetchScanIntervalInBytes; \ |
712 const intx copy_interval = PrefetchCopyIntervalInBytes; \ | |
713 while (q < t) { \ | |
714 if (!oop(q)->is_gc_marked()) { \ | |
715 /* mark is pointer to next marked oop */ \ | |
716 debug_only(prev_q = q); \ | |
717 q = (HeapWord*) oop(q)->mark()->decode_pointer(); \ | |
718 assert(q > prev_q, "we should be moving forward through memory"); \ | |
719 } else { \ | |
720 /* prefetch beyond q */ \ | |
0 | 721 Prefetch::read(q, scan_interval); \ |
722 \ | |
723 /* size and destination */ \ | |
724 size_t size = obj_size(q); \ | |
725 HeapWord* compaction_top = (HeapWord*)oop(q)->forwardee(); \ | |
726 \ | |
356 | 727 /* prefetch beyond compaction_top */ \ |
0 | 728 Prefetch::write(compaction_top, copy_interval); \ |
729 \ | |
356 | 730 /* copy object and reinit its mark */ \ |
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731 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::live_oop_moved_to(q, size, \ |
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732 compaction_top)); \ |
356 | 733 assert(q != compaction_top, "everything in this pass should be moving"); \ |
734 Copy::aligned_conjoint_words(q, compaction_top, size); \ | |
735 oop(compaction_top)->init_mark(); \ | |
736 assert(oop(compaction_top)->klass() != NULL, "should have a class"); \ | |
0 | 737 \ |
356 | 738 debug_only(prev_q = q); \ |
0 | 739 q += size; \ |
356 | 740 } \ |
741 } \ | |
0 | 742 \ |
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743 /* Let's remember if we were empty before we did the compaction. */ \ |
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744 bool was_empty = used_region().is_empty(); \ |
0 | 745 /* Reset space after compaction is complete */ \ |
356 | 746 reset_after_compaction(); \ |
0 | 747 /* We do this clear, below, since it has overloaded meanings for some */ \ |
748 /* space subtypes. For example, OffsetTableContigSpace's that were */ \ | |
749 /* compacted into will have had their offset table thresholds updated */ \ | |
750 /* continuously, but those that weren't need to have their thresholds */ \ | |
751 /* re-initialized. Also mangles unused area for debugging. */ \ | |
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752 if (used_region().is_empty()) { \ |
356 | 753 if (!was_empty) clear(SpaceDecorator::Mangle); \ |
0 | 754 } else { \ |
755 if (ZapUnusedHeapArea) mangle_unused_area(); \ | |
756 } \ | |
757 } | |
758 | |
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759 class GenSpaceMangler; |
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760 |
0 | 761 // A space in which the free area is contiguous. It therefore supports |
762 // faster allocation, and compaction. | |
763 class ContiguousSpace: public CompactibleSpace { | |
764 friend class OneContigSpaceCardGeneration; | |
765 friend class VMStructs; | |
766 protected: | |
767 HeapWord* _top; | |
768 HeapWord* _concurrent_iteration_safe_limit; | |
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769 // A helper for mangling the unused area of the space in debug builds. |
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770 GenSpaceMangler* _mangler; |
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771 |
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772 GenSpaceMangler* mangler() { return _mangler; } |
0 | 773 |
774 // Allocation helpers (return NULL if full). | |
775 inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value); | |
776 inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value); | |
777 | |
778 public: | |
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779 ContiguousSpace(); |
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780 ~ContiguousSpace(); |
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781 |
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782 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); |
356 | 783 virtual void clear(bool mangle_space); |
0 | 784 |
785 // Accessors | |
786 HeapWord* top() const { return _top; } | |
787 void set_top(HeapWord* value) { _top = value; } | |
788 | |
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789 virtual void set_saved_mark() { _saved_mark_word = top(); } |
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790 void reset_saved_mark() { _saved_mark_word = bottom(); } |
0 | 791 |
792 WaterMark bottom_mark() { return WaterMark(this, bottom()); } | |
793 WaterMark top_mark() { return WaterMark(this, top()); } | |
794 WaterMark saved_mark() { return WaterMark(this, saved_mark_word()); } | |
795 bool saved_mark_at_top() const { return saved_mark_word() == top(); } | |
796 | |
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797 // In debug mode mangle (write it with a particular bit |
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798 // pattern) the unused part of a space. |
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799 |
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800 // Used to save the an address in a space for later use during mangling. |
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801 void set_top_for_allocations(HeapWord* v) PRODUCT_RETURN; |
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802 // Used to save the space's current top for later use during mangling. |
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803 void set_top_for_allocations() PRODUCT_RETURN; |
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804 |
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805 // Mangle regions in the space from the current top up to the |
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806 // previously mangled part of the space. |
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807 void mangle_unused_area() PRODUCT_RETURN; |
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808 // Mangle [top, end) |
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809 void mangle_unused_area_complete() PRODUCT_RETURN; |
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810 // Mangle the given MemRegion. |
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811 void mangle_region(MemRegion mr) PRODUCT_RETURN; |
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812 |
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813 // Do some sparse checking on the area that should have been mangled. |
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814 void check_mangled_unused_area(HeapWord* limit) PRODUCT_RETURN; |
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815 // Check the complete area that should have been mangled. |
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816 // This code may be NULL depending on the macro DEBUG_MANGLING. |
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817 void check_mangled_unused_area_complete() PRODUCT_RETURN; |
0 | 818 |
819 // Size computations: sizes in bytes. | |
820 size_t capacity() const { return byte_size(bottom(), end()); } | |
821 size_t used() const { return byte_size(bottom(), top()); } | |
822 size_t free() const { return byte_size(top(), end()); } | |
823 | |
824 // Override from space. | |
825 bool is_in(const void* p) const; | |
826 | |
827 virtual bool is_free_block(const HeapWord* p) const; | |
828 | |
829 // In a contiguous space we have a more obvious bound on what parts | |
830 // contain objects. | |
831 MemRegion used_region() const { return MemRegion(bottom(), top()); } | |
832 | |
833 MemRegion used_region_at_save_marks() const { | |
834 return MemRegion(bottom(), saved_mark_word()); | |
835 } | |
836 | |
837 // Allocation (return NULL if full) | |
838 virtual HeapWord* allocate(size_t word_size); | |
839 virtual HeapWord* par_allocate(size_t word_size); | |
840 | |
841 virtual bool obj_allocated_since_save_marks(const oop obj) const { | |
842 return (HeapWord*)obj >= saved_mark_word(); | |
843 } | |
844 | |
845 // Iteration | |
846 void oop_iterate(OopClosure* cl); | |
847 void oop_iterate(MemRegion mr, OopClosure* cl); | |
848 void object_iterate(ObjectClosure* blk); | |
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849 // For contiguous spaces this method will iterate safely over objects |
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850 // in the space (i.e., between bottom and top) when at a safepoint. |
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851 void safe_object_iterate(ObjectClosure* blk); |
0 | 852 void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl); |
853 // iterates on objects up to the safe limit | |
854 HeapWord* object_iterate_careful(ObjectClosureCareful* cl); | |
855 inline HeapWord* concurrent_iteration_safe_limit(); | |
856 // changes the safe limit, all objects from bottom() to the new | |
857 // limit should be properly initialized | |
858 inline void set_concurrent_iteration_safe_limit(HeapWord* new_limit); | |
859 | |
860 #ifndef SERIALGC | |
861 // In support of parallel oop_iterate. | |
862 #define ContigSpace_PAR_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ | |
863 void par_oop_iterate(MemRegion mr, OopClosureType* blk); | |
864 | |
865 ALL_PAR_OOP_ITERATE_CLOSURES(ContigSpace_PAR_OOP_ITERATE_DECL) | |
866 #undef ContigSpace_PAR_OOP_ITERATE_DECL | |
867 #endif // SERIALGC | |
868 | |
869 // Compaction support | |
870 virtual void reset_after_compaction() { | |
871 assert(compaction_top() >= bottom() && compaction_top() <= end(), "should point inside space"); | |
872 set_top(compaction_top()); | |
873 // set new iteration safe limit | |
874 set_concurrent_iteration_safe_limit(compaction_top()); | |
875 } | |
876 virtual size_t minimum_free_block_size() const { return 0; } | |
877 | |
878 // Override. | |
879 DirtyCardToOopClosure* new_dcto_cl(OopClosure* cl, | |
880 CardTableModRefBS::PrecisionStyle precision, | |
881 HeapWord* boundary = NULL); | |
882 | |
883 // Apply "blk->do_oop" to the addresses of all reference fields in objects | |
884 // starting with the _saved_mark_word, which was noted during a generation's | |
885 // save_marks and is required to denote the head of an object. | |
886 // Fields in objects allocated by applications of the closure | |
887 // *are* included in the iteration. | |
888 // Updates _saved_mark_word to point to just after the last object | |
889 // iterated over. | |
890 #define ContigSpace_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ | |
891 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk); | |
892 | |
893 ALL_SINCE_SAVE_MARKS_CLOSURES(ContigSpace_OOP_SINCE_SAVE_MARKS_DECL) | |
894 #undef ContigSpace_OOP_SINCE_SAVE_MARKS_DECL | |
895 | |
896 // Same as object_iterate, but starting from "mark", which is required | |
897 // to denote the start of an object. Objects allocated by | |
898 // applications of the closure *are* included in the iteration. | |
899 virtual void object_iterate_from(WaterMark mark, ObjectClosure* blk); | |
900 | |
901 // Very inefficient implementation. | |
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902 virtual HeapWord* block_start_const(const void* p) const; |
0 | 903 size_t block_size(const HeapWord* p) const; |
904 // If a block is in the allocated area, it is an object. | |
905 bool block_is_obj(const HeapWord* p) const { return p < top(); } | |
906 | |
907 // Addresses for inlined allocation | |
908 HeapWord** top_addr() { return &_top; } | |
909 HeapWord** end_addr() { return &_end; } | |
910 | |
911 // Overrides for more efficient compaction support. | |
912 void prepare_for_compaction(CompactPoint* cp); | |
913 | |
914 // PrintHeapAtGC support. | |
915 virtual void print_on(outputStream* st) const; | |
916 | |
917 // Checked dynamic downcasts. | |
918 virtual ContiguousSpace* toContiguousSpace() { | |
919 return this; | |
920 } | |
921 | |
922 // Debugging | |
923 virtual void verify(bool allow_dirty) const; | |
924 | |
925 // Used to increase collection frequency. "factor" of 0 means entire | |
926 // space. | |
927 void allocate_temporary_filler(int factor); | |
928 | |
929 }; | |
930 | |
931 | |
932 // A dirty card to oop closure that does filtering. | |
933 // It knows how to filter out objects that are outside of the _boundary. | |
934 class Filtering_DCTOC : public DirtyCardToOopClosure { | |
935 protected: | |
936 // Override. | |
937 void walk_mem_region(MemRegion mr, | |
938 HeapWord* bottom, HeapWord* top); | |
939 | |
940 // Walk the given memory region, from bottom to top, applying | |
941 // the given oop closure to (possibly) all objects found. The | |
942 // given oop closure may or may not be the same as the oop | |
943 // closure with which this closure was created, as it may | |
944 // be a filtering closure which makes use of the _boundary. | |
945 // We offer two signatures, so the FilteringClosure static type is | |
946 // apparent. | |
947 virtual void walk_mem_region_with_cl(MemRegion mr, | |
948 HeapWord* bottom, HeapWord* top, | |
949 OopClosure* cl) = 0; | |
950 virtual void walk_mem_region_with_cl(MemRegion mr, | |
951 HeapWord* bottom, HeapWord* top, | |
952 FilteringClosure* cl) = 0; | |
953 | |
954 public: | |
955 Filtering_DCTOC(Space* sp, OopClosure* cl, | |
956 CardTableModRefBS::PrecisionStyle precision, | |
957 HeapWord* boundary) : | |
958 DirtyCardToOopClosure(sp, cl, precision, boundary) {} | |
959 }; | |
960 | |
961 // A dirty card to oop closure for contiguous spaces | |
962 // (ContiguousSpace and sub-classes). | |
963 // It is a FilteringClosure, as defined above, and it knows: | |
964 // | |
965 // 1. That the actual top of any area in a memory region | |
966 // contained by the space is bounded by the end of the contiguous | |
967 // region of the space. | |
968 // 2. That the space is really made up of objects and not just | |
969 // blocks. | |
970 | |
971 class ContiguousSpaceDCTOC : public Filtering_DCTOC { | |
972 protected: | |
973 // Overrides. | |
974 HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj); | |
975 | |
976 virtual void walk_mem_region_with_cl(MemRegion mr, | |
977 HeapWord* bottom, HeapWord* top, | |
978 OopClosure* cl); | |
979 virtual void walk_mem_region_with_cl(MemRegion mr, | |
980 HeapWord* bottom, HeapWord* top, | |
981 FilteringClosure* cl); | |
982 | |
983 public: | |
984 ContiguousSpaceDCTOC(ContiguousSpace* sp, OopClosure* cl, | |
985 CardTableModRefBS::PrecisionStyle precision, | |
986 HeapWord* boundary) : | |
987 Filtering_DCTOC(sp, cl, precision, boundary) | |
988 {} | |
989 }; | |
990 | |
991 | |
992 // Class EdenSpace describes eden-space in new generation. | |
993 | |
994 class DefNewGeneration; | |
995 | |
996 class EdenSpace : public ContiguousSpace { | |
997 friend class VMStructs; | |
998 private: | |
999 DefNewGeneration* _gen; | |
1000 | |
1001 // _soft_end is used as a soft limit on allocation. As soft limits are | |
1002 // reached, the slow-path allocation code can invoke other actions and then | |
1003 // adjust _soft_end up to a new soft limit or to end(). | |
1004 HeapWord* _soft_end; | |
1005 | |
1006 public: | |
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1007 EdenSpace(DefNewGeneration* gen) : |
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1008 _gen(gen), _soft_end(NULL) {} |
0 | 1009 |
1010 // Get/set just the 'soft' limit. | |
1011 HeapWord* soft_end() { return _soft_end; } | |
1012 HeapWord** soft_end_addr() { return &_soft_end; } | |
1013 void set_soft_end(HeapWord* value) { _soft_end = value; } | |
1014 | |
1015 // Override. | |
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1016 void clear(bool mangle_space); |
0 | 1017 |
1018 // Set both the 'hard' and 'soft' limits (_end and _soft_end). | |
1019 void set_end(HeapWord* value) { | |
1020 set_soft_end(value); | |
1021 ContiguousSpace::set_end(value); | |
1022 } | |
1023 | |
1024 // Allocation (return NULL if full) | |
1025 HeapWord* allocate(size_t word_size); | |
1026 HeapWord* par_allocate(size_t word_size); | |
1027 }; | |
1028 | |
1029 // Class ConcEdenSpace extends EdenSpace for the sake of safe | |
1030 // allocation while soft-end is being modified concurrently | |
1031 | |
1032 class ConcEdenSpace : public EdenSpace { | |
1033 public: | |
1034 ConcEdenSpace(DefNewGeneration* gen) : EdenSpace(gen) { } | |
1035 | |
1036 // Allocation (return NULL if full) | |
1037 HeapWord* par_allocate(size_t word_size); | |
1038 }; | |
1039 | |
1040 | |
1041 // A ContigSpace that Supports an efficient "block_start" operation via | |
1042 // a BlockOffsetArray (whose BlockOffsetSharedArray may be shared with | |
1043 // other spaces.) This is the abstract base class for old generation | |
1044 // (tenured, perm) spaces. | |
1045 | |
1046 class OffsetTableContigSpace: public ContiguousSpace { | |
1047 friend class VMStructs; | |
1048 protected: | |
1049 BlockOffsetArrayContigSpace _offsets; | |
1050 Mutex _par_alloc_lock; | |
1051 | |
1052 public: | |
1053 // Constructor | |
1054 OffsetTableContigSpace(BlockOffsetSharedArray* sharedOffsetArray, | |
1055 MemRegion mr); | |
1056 | |
1057 void set_bottom(HeapWord* value); | |
1058 void set_end(HeapWord* value); | |
1059 | |
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1060 void clear(bool mangle_space); |
0 | 1061 |
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1062 inline HeapWord* block_start_const(const void* p) const; |
0 | 1063 |
1064 // Add offset table update. | |
1065 virtual inline HeapWord* allocate(size_t word_size); | |
1066 inline HeapWord* par_allocate(size_t word_size); | |
1067 | |
1068 // MarkSweep support phase3 | |
1069 virtual HeapWord* initialize_threshold(); | |
1070 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); | |
1071 | |
1072 virtual void print_on(outputStream* st) const; | |
1073 | |
1074 // Debugging | |
1075 void verify(bool allow_dirty) const; | |
1076 | |
1077 // Shared space support | |
1078 void serialize_block_offset_array_offsets(SerializeOopClosure* soc); | |
1079 }; | |
1080 | |
1081 | |
1082 // Class TenuredSpace is used by TenuredGeneration | |
1083 | |
1084 class TenuredSpace: public OffsetTableContigSpace { | |
1085 friend class VMStructs; | |
1086 protected: | |
1087 // Mark sweep support | |
438 | 1088 size_t allowed_dead_ratio() const; |
0 | 1089 public: |
1090 // Constructor | |
1091 TenuredSpace(BlockOffsetSharedArray* sharedOffsetArray, | |
1092 MemRegion mr) : | |
1093 OffsetTableContigSpace(sharedOffsetArray, mr) {} | |
1094 }; | |
1095 | |
1096 | |
1097 // Class ContigPermSpace is used by CompactingPermGen | |
1098 | |
1099 class ContigPermSpace: public OffsetTableContigSpace { | |
1100 friend class VMStructs; | |
1101 protected: | |
1102 // Mark sweep support | |
438 | 1103 size_t allowed_dead_ratio() const; |
0 | 1104 public: |
1105 // Constructor | |
1106 ContigPermSpace(BlockOffsetSharedArray* sharedOffsetArray, MemRegion mr) : | |
1107 OffsetTableContigSpace(sharedOffsetArray, mr) {} | |
1108 }; |