Mercurial > hg > graal-jvmci-8
annotate src/share/vm/memory/space.hpp @ 3917:eca1193ca245
4965777: GC changes to support use of discovered field for pending references
Summary: If and when the reference handler thread is able to use the discovered field to link reference objects in its pending list, so will GC. In that case, GC will scan through this field once a reference object has been placed on the pending list, but not scan that field before that stage, as the field is used by the concurrent GC thread to link discovered objects. When ReferenceHandleR thread does not use the discovered field for the purpose of linking the elements in the pending list, as would be the case in older JDKs, the JVM will fall back to the old behaviour of using the next field for that purpose.
Reviewed-by: jcoomes, mchung, stefank
author | ysr |
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date | Wed, 07 Sep 2011 13:55:42 -0700 |
parents | f95d63e2154a |
children | f08d439fab8c |
rev | line source |
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0 | 1 /* |
1972 | 2 * Copyright (c) 1997, 2010, Oracle and/or its affiliates. All rights reserved. |
0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
4 * | |
5 * This code is free software; you can redistribute it and/or modify it | |
6 * under the terms of the GNU General Public License version 2 only, as | |
7 * published by the Free Software Foundation. | |
8 * | |
9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
12 * version 2 for more details (a copy is included in the LICENSE file that | |
13 * accompanied this code). | |
14 * | |
15 * You should have received a copy of the GNU General Public License version | |
16 * 2 along with this work; if not, write to the Free Software Foundation, | |
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
18 * | |
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19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
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20 * or visit www.oracle.com if you need additional information or have any |
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21 * questions. |
0 | 22 * |
23 */ | |
24 | |
1972 | 25 #ifndef SHARE_VM_MEMORY_SPACE_HPP |
26 #define SHARE_VM_MEMORY_SPACE_HPP | |
27 | |
28 #include "memory/allocation.hpp" | |
29 #include "memory/blockOffsetTable.hpp" | |
30 #include "memory/cardTableModRefBS.hpp" | |
31 #include "memory/iterator.hpp" | |
32 #include "memory/memRegion.hpp" | |
33 #include "memory/watermark.hpp" | |
34 #include "oops/markOop.hpp" | |
35 #include "runtime/mutexLocker.hpp" | |
36 #include "runtime/prefetch.hpp" | |
37 #include "utilities/workgroup.hpp" | |
38 #ifdef TARGET_OS_FAMILY_linux | |
39 # include "os_linux.inline.hpp" | |
40 #endif | |
41 #ifdef TARGET_OS_FAMILY_solaris | |
42 # include "os_solaris.inline.hpp" | |
43 #endif | |
44 #ifdef TARGET_OS_FAMILY_windows | |
45 # include "os_windows.inline.hpp" | |
46 #endif | |
47 | |
0 | 48 // A space is an abstraction for the "storage units" backing |
49 // up the generation abstraction. It includes specific | |
50 // implementations for keeping track of free and used space, | |
51 // for iterating over objects and free blocks, etc. | |
52 | |
53 // Here's the Space hierarchy: | |
54 // | |
55 // - Space -- an asbtract base class describing a heap area | |
56 // - CompactibleSpace -- a space supporting compaction | |
57 // - CompactibleFreeListSpace -- (used for CMS generation) | |
58 // - ContiguousSpace -- a compactible space in which all free space | |
59 // is contiguous | |
60 // - EdenSpace -- contiguous space used as nursery | |
61 // - ConcEdenSpace -- contiguous space with a 'soft end safe' allocation | |
62 // - OffsetTableContigSpace -- contiguous space with a block offset array | |
63 // that allows "fast" block_start calls | |
64 // - TenuredSpace -- (used for TenuredGeneration) | |
65 // - ContigPermSpace -- an offset table contiguous space for perm gen | |
66 | |
67 // Forward decls. | |
68 class Space; | |
69 class BlockOffsetArray; | |
70 class BlockOffsetArrayContigSpace; | |
71 class Generation; | |
72 class CompactibleSpace; | |
73 class BlockOffsetTable; | |
74 class GenRemSet; | |
75 class CardTableRS; | |
76 class DirtyCardToOopClosure; | |
77 | |
78 // An oop closure that is circumscribed by a filtering memory region. | |
113
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79 class SpaceMemRegionOopsIterClosure: public OopClosure { |
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80 private: |
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81 OopClosure* _cl; |
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82 MemRegion _mr; |
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83 protected: |
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84 template <class T> void do_oop_work(T* p) { |
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85 if (_mr.contains(p)) { |
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86 _cl->do_oop(p); |
0 | 87 } |
88 } | |
113
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89 public: |
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90 SpaceMemRegionOopsIterClosure(OopClosure* cl, MemRegion mr): |
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91 _cl(cl), _mr(mr) {} |
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92 virtual void do_oop(oop* p); |
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93 virtual void do_oop(narrowOop* p); |
0 | 94 }; |
95 | |
96 // A Space describes a heap area. Class Space is an abstract | |
97 // base class. | |
98 // | |
99 // Space supports allocation, size computation and GC support is provided. | |
100 // | |
101 // Invariant: bottom() and end() are on page_size boundaries and | |
102 // bottom() <= top() <= end() | |
103 // top() is inclusive and end() is exclusive. | |
104 | |
105 class Space: public CHeapObj { | |
106 friend class VMStructs; | |
107 protected: | |
108 HeapWord* _bottom; | |
109 HeapWord* _end; | |
110 | |
111 // Used in support of save_marks() | |
112 HeapWord* _saved_mark_word; | |
113 | |
114 MemRegionClosure* _preconsumptionDirtyCardClosure; | |
115 | |
116 // A sequential tasks done structure. This supports | |
117 // parallel GC, where we have threads dynamically | |
118 // claiming sub-tasks from a larger parallel task. | |
119 SequentialSubTasksDone _par_seq_tasks; | |
120 | |
121 Space(): | |
122 _bottom(NULL), _end(NULL), _preconsumptionDirtyCardClosure(NULL) { } | |
123 | |
124 public: | |
125 // Accessors | |
126 HeapWord* bottom() const { return _bottom; } | |
127 HeapWord* end() const { return _end; } | |
128 virtual void set_bottom(HeapWord* value) { _bottom = value; } | |
129 virtual void set_end(HeapWord* value) { _end = value; } | |
130 | |
342
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131 virtual HeapWord* saved_mark_word() const { return _saved_mark_word; } |
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132 |
0 | 133 void set_saved_mark_word(HeapWord* p) { _saved_mark_word = p; } |
134 | |
135 MemRegionClosure* preconsumptionDirtyCardClosure() const { | |
136 return _preconsumptionDirtyCardClosure; | |
137 } | |
138 void setPreconsumptionDirtyCardClosure(MemRegionClosure* cl) { | |
139 _preconsumptionDirtyCardClosure = cl; | |
140 } | |
141 | |
142 // Returns a subregion of the space containing all the objects in | |
143 // the space. | |
144 virtual MemRegion used_region() const { return MemRegion(bottom(), end()); } | |
145 | |
146 // Returns a region that is guaranteed to contain (at least) all objects | |
147 // allocated at the time of the last call to "save_marks". If the space | |
148 // initializes its DirtyCardToOopClosure's specifying the "contig" option | |
149 // (that is, if the space is contiguous), then this region must contain only | |
150 // such objects: the memregion will be from the bottom of the region to the | |
151 // saved mark. Otherwise, the "obj_allocated_since_save_marks" method of | |
152 // the space must distiguish between objects in the region allocated before | |
153 // and after the call to save marks. | |
154 virtual MemRegion used_region_at_save_marks() const { | |
155 return MemRegion(bottom(), saved_mark_word()); | |
156 } | |
157 | |
342
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158 // Initialization. |
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159 // "initialize" should be called once on a space, before it is used for |
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160 // any purpose. The "mr" arguments gives the bounds of the space, and |
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161 // the "clear_space" argument should be true unless the memory in "mr" is |
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162 // known to be zeroed. |
263
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163 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); |
342
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164 |
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165 // The "clear" method must be called on a region that may have |
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166 // had allocation performed in it, but is now to be considered empty. |
263
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167 virtual void clear(bool mangle_space); |
0 | 168 |
169 // For detecting GC bugs. Should only be called at GC boundaries, since | |
170 // some unused space may be used as scratch space during GC's. | |
171 // Default implementation does nothing. We also call this when expanding | |
172 // a space to satisfy an allocation request. See bug #4668531 | |
173 virtual void mangle_unused_area() {} | |
263
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174 virtual void mangle_unused_area_complete() {} |
0 | 175 virtual void mangle_region(MemRegion mr) {} |
176 | |
177 // Testers | |
178 bool is_empty() const { return used() == 0; } | |
179 bool not_empty() const { return used() > 0; } | |
180 | |
181 // Returns true iff the given the space contains the | |
182 // given address as part of an allocated object. For | |
183 // ceratin kinds of spaces, this might be a potentially | |
184 // expensive operation. To prevent performance problems | |
185 // on account of its inadvertent use in product jvm's, | |
186 // we restrict its use to assertion checks only. | |
187 virtual bool is_in(const void* p) const; | |
188 | |
189 // Returns true iff the given reserved memory of the space contains the | |
190 // given address. | |
191 bool is_in_reserved(const void* p) const { return _bottom <= p && p < _end; } | |
192 | |
193 // Returns true iff the given block is not allocated. | |
194 virtual bool is_free_block(const HeapWord* p) const = 0; | |
195 | |
196 // Test whether p is double-aligned | |
197 static bool is_aligned(void* p) { | |
198 return ((intptr_t)p & (sizeof(double)-1)) == 0; | |
199 } | |
200 | |
201 // Size computations. Sizes are in bytes. | |
202 size_t capacity() const { return byte_size(bottom(), end()); } | |
203 virtual size_t used() const = 0; | |
204 virtual size_t free() const = 0; | |
205 | |
206 // Iterate over all the ref-containing fields of all objects in the | |
207 // space, calling "cl.do_oop" on each. Fields in objects allocated by | |
208 // applications of the closure are not included in the iteration. | |
209 virtual void oop_iterate(OopClosure* cl); | |
210 | |
211 // Same as above, restricted to the intersection of a memory region and | |
212 // the space. Fields in objects allocated by applications of the closure | |
213 // are not included in the iteration. | |
214 virtual void oop_iterate(MemRegion mr, OopClosure* cl) = 0; | |
215 | |
216 // Iterate over all objects in the space, calling "cl.do_object" on | |
217 // each. Objects allocated by applications of the closure are not | |
218 // included in the iteration. | |
219 virtual void object_iterate(ObjectClosure* blk) = 0; | |
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220 // Similar to object_iterate() except only iterates over |
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221 // objects whose internal references point to objects in the space. |
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222 virtual void safe_object_iterate(ObjectClosure* blk) = 0; |
0 | 223 |
224 // Iterate over all objects that intersect with mr, calling "cl->do_object" | |
225 // on each. There is an exception to this: if this closure has already | |
226 // been invoked on an object, it may skip such objects in some cases. This is | |
227 // Most likely to happen in an "upwards" (ascending address) iteration of | |
228 // MemRegions. | |
229 virtual void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl); | |
230 | |
231 // Iterate over as many initialized objects in the space as possible, | |
232 // calling "cl.do_object_careful" on each. Return NULL if all objects | |
233 // in the space (at the start of the iteration) were iterated over. | |
234 // Return an address indicating the extent of the iteration in the | |
235 // event that the iteration had to return because of finding an | |
236 // uninitialized object in the space, or if the closure "cl" | |
237 // signalled early termination. | |
238 virtual HeapWord* object_iterate_careful(ObjectClosureCareful* cl); | |
239 virtual HeapWord* object_iterate_careful_m(MemRegion mr, | |
240 ObjectClosureCareful* cl); | |
241 | |
242 // Create and return a new dirty card to oop closure. Can be | |
243 // overriden to return the appropriate type of closure | |
244 // depending on the type of space in which the closure will | |
245 // operate. ResourceArea allocated. | |
246 virtual DirtyCardToOopClosure* new_dcto_cl(OopClosure* cl, | |
247 CardTableModRefBS::PrecisionStyle precision, | |
248 HeapWord* boundary = NULL); | |
249 | |
250 // If "p" is in the space, returns the address of the start of the | |
251 // "block" that contains "p". We say "block" instead of "object" since | |
252 // some heaps may not pack objects densely; a chunk may either be an | |
253 // object or a non-object. If "p" is not in the space, return NULL. | |
342
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254 virtual HeapWord* block_start_const(const void* p) const = 0; |
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255 |
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256 // The non-const version may have benevolent side effects on the data |
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257 // structure supporting these calls, possibly speeding up future calls. |
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258 // The default implementation, however, is simply to call the const |
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259 // version. |
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260 inline virtual HeapWord* block_start(const void* p); |
0 | 261 |
262 // Requires "addr" to be the start of a chunk, and returns its size. | |
263 // "addr + size" is required to be the start of a new chunk, or the end | |
264 // of the active area of the heap. | |
265 virtual size_t block_size(const HeapWord* addr) const = 0; | |
266 | |
267 // Requires "addr" to be the start of a block, and returns "TRUE" iff | |
268 // the block is an object. | |
269 virtual bool block_is_obj(const HeapWord* addr) const = 0; | |
270 | |
271 // Requires "addr" to be the start of a block, and returns "TRUE" iff | |
272 // the block is an object and the object is alive. | |
273 virtual bool obj_is_alive(const HeapWord* addr) const; | |
274 | |
275 // Allocation (return NULL if full). Assumes the caller has established | |
276 // mutually exclusive access to the space. | |
277 virtual HeapWord* allocate(size_t word_size) = 0; | |
278 | |
279 // Allocation (return NULL if full). Enforces mutual exclusion internally. | |
280 virtual HeapWord* par_allocate(size_t word_size) = 0; | |
281 | |
282 // Returns true if this object has been allocated since a | |
283 // generation's "save_marks" call. | |
284 virtual bool obj_allocated_since_save_marks(const oop obj) const = 0; | |
285 | |
286 // Mark-sweep-compact support: all spaces can update pointers to objects | |
287 // moving as a part of compaction. | |
288 virtual void adjust_pointers(); | |
289 | |
290 // PrintHeapAtGC support | |
291 virtual void print() const; | |
292 virtual void print_on(outputStream* st) const; | |
293 virtual void print_short() const; | |
294 virtual void print_short_on(outputStream* st) const; | |
295 | |
296 | |
297 // Accessor for parallel sequential tasks. | |
298 SequentialSubTasksDone* par_seq_tasks() { return &_par_seq_tasks; } | |
299 | |
300 // IF "this" is a ContiguousSpace, return it, else return NULL. | |
301 virtual ContiguousSpace* toContiguousSpace() { | |
302 return NULL; | |
303 } | |
304 | |
305 // Debugging | |
306 virtual void verify(bool allow_dirty) const = 0; | |
307 }; | |
308 | |
309 // A MemRegionClosure (ResourceObj) whose "do_MemRegion" function applies an | |
310 // OopClosure to (the addresses of) all the ref-containing fields that could | |
311 // be modified by virtue of the given MemRegion being dirty. (Note that | |
312 // because of the imprecise nature of the write barrier, this may iterate | |
313 // over oops beyond the region.) | |
314 // This base type for dirty card to oop closures handles memory regions | |
315 // in non-contiguous spaces with no boundaries, and should be sub-classed | |
316 // to support other space types. See ContiguousDCTOC for a sub-class | |
317 // that works with ContiguousSpaces. | |
318 | |
319 class DirtyCardToOopClosure: public MemRegionClosureRO { | |
320 protected: | |
321 OopClosure* _cl; | |
322 Space* _sp; | |
323 CardTableModRefBS::PrecisionStyle _precision; | |
324 HeapWord* _boundary; // If non-NULL, process only non-NULL oops | |
325 // pointing below boundary. | |
342
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326 HeapWord* _min_done; // ObjHeadPreciseArray precision requires |
0 | 327 // a downwards traversal; this is the |
328 // lowest location already done (or, | |
329 // alternatively, the lowest address that | |
330 // shouldn't be done again. NULL means infinity.) | |
331 NOT_PRODUCT(HeapWord* _last_bottom;) | |
342
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332 NOT_PRODUCT(HeapWord* _last_explicit_min_done;) |
0 | 333 |
334 // Get the actual top of the area on which the closure will | |
335 // operate, given where the top is assumed to be (the end of the | |
336 // memory region passed to do_MemRegion) and where the object | |
337 // at the top is assumed to start. For example, an object may | |
338 // start at the top but actually extend past the assumed top, | |
339 // in which case the top becomes the end of the object. | |
340 virtual HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj); | |
341 | |
342 // Walk the given memory region from bottom to (actual) top | |
343 // looking for objects and applying the oop closure (_cl) to | |
344 // them. The base implementation of this treats the area as | |
345 // blocks, where a block may or may not be an object. Sub- | |
346 // classes should override this to provide more accurate | |
347 // or possibly more efficient walking. | |
348 virtual void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top); | |
349 | |
350 public: | |
351 DirtyCardToOopClosure(Space* sp, OopClosure* cl, | |
352 CardTableModRefBS::PrecisionStyle precision, | |
353 HeapWord* boundary) : | |
354 _sp(sp), _cl(cl), _precision(precision), _boundary(boundary), | |
355 _min_done(NULL) { | |
342
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356 NOT_PRODUCT(_last_bottom = NULL); |
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357 NOT_PRODUCT(_last_explicit_min_done = NULL); |
0 | 358 } |
359 | |
360 void do_MemRegion(MemRegion mr); | |
361 | |
362 void set_min_done(HeapWord* min_done) { | |
363 _min_done = min_done; | |
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364 NOT_PRODUCT(_last_explicit_min_done = _min_done); |
0 | 365 } |
366 #ifndef PRODUCT | |
367 void set_last_bottom(HeapWord* last_bottom) { | |
368 _last_bottom = last_bottom; | |
369 } | |
370 #endif | |
371 }; | |
372 | |
373 // A structure to represent a point at which objects are being copied | |
374 // during compaction. | |
375 class CompactPoint : public StackObj { | |
376 public: | |
377 Generation* gen; | |
378 CompactibleSpace* space; | |
379 HeapWord* threshold; | |
380 CompactPoint(Generation* _gen, CompactibleSpace* _space, | |
381 HeapWord* _threshold) : | |
382 gen(_gen), space(_space), threshold(_threshold) {} | |
383 }; | |
384 | |
385 | |
386 // A space that supports compaction operations. This is usually, but not | |
387 // necessarily, a space that is normally contiguous. But, for example, a | |
388 // free-list-based space whose normal collection is a mark-sweep without | |
389 // compaction could still support compaction in full GC's. | |
390 | |
391 class CompactibleSpace: public Space { | |
392 friend class VMStructs; | |
393 friend class CompactibleFreeListSpace; | |
394 friend class CompactingPermGenGen; | |
395 friend class CMSPermGenGen; | |
396 private: | |
397 HeapWord* _compaction_top; | |
398 CompactibleSpace* _next_compaction_space; | |
399 | |
400 public: | |
347
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401 CompactibleSpace() : |
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402 _compaction_top(NULL), _next_compaction_space(NULL) {} |
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403 |
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404 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); |
356 | 405 virtual void clear(bool mangle_space); |
0 | 406 |
407 // Used temporarily during a compaction phase to hold the value | |
408 // top should have when compaction is complete. | |
409 HeapWord* compaction_top() const { return _compaction_top; } | |
410 | |
411 void set_compaction_top(HeapWord* value) { | |
412 assert(value == NULL || (value >= bottom() && value <= end()), | |
413 "should point inside space"); | |
414 _compaction_top = value; | |
415 } | |
416 | |
417 // Perform operations on the space needed after a compaction | |
418 // has been performed. | |
419 virtual void reset_after_compaction() {} | |
420 | |
421 // Returns the next space (in the current generation) to be compacted in | |
422 // the global compaction order. Also is used to select the next | |
423 // space into which to compact. | |
424 | |
425 virtual CompactibleSpace* next_compaction_space() const { | |
426 return _next_compaction_space; | |
427 } | |
428 | |
429 void set_next_compaction_space(CompactibleSpace* csp) { | |
430 _next_compaction_space = csp; | |
431 } | |
432 | |
433 // MarkSweep support phase2 | |
434 | |
435 // Start the process of compaction of the current space: compute | |
436 // post-compaction addresses, and insert forwarding pointers. The fields | |
437 // "cp->gen" and "cp->compaction_space" are the generation and space into | |
438 // which we are currently compacting. This call updates "cp" as necessary, | |
439 // and leaves the "compaction_top" of the final value of | |
440 // "cp->compaction_space" up-to-date. Offset tables may be updated in | |
441 // this phase as if the final copy had occurred; if so, "cp->threshold" | |
442 // indicates when the next such action should be taken. | |
443 virtual void prepare_for_compaction(CompactPoint* cp); | |
444 // MarkSweep support phase3 | |
445 virtual void adjust_pointers(); | |
446 // MarkSweep support phase4 | |
447 virtual void compact(); | |
448 | |
449 // The maximum percentage of objects that can be dead in the compacted | |
450 // live part of a compacted space ("deadwood" support.) | |
438 | 451 virtual size_t allowed_dead_ratio() const { return 0; }; |
0 | 452 |
453 // Some contiguous spaces may maintain some data structures that should | |
454 // be updated whenever an allocation crosses a boundary. This function | |
455 // returns the first such boundary. | |
456 // (The default implementation returns the end of the space, so the | |
457 // boundary is never crossed.) | |
458 virtual HeapWord* initialize_threshold() { return end(); } | |
459 | |
460 // "q" is an object of the given "size" that should be forwarded; | |
461 // "cp" names the generation ("gen") and containing "this" (which must | |
462 // also equal "cp->space"). "compact_top" is where in "this" the | |
463 // next object should be forwarded to. If there is room in "this" for | |
464 // the object, insert an appropriate forwarding pointer in "q". | |
465 // If not, go to the next compaction space (there must | |
466 // be one, since compaction must succeed -- we go to the first space of | |
467 // the previous generation if necessary, updating "cp"), reset compact_top | |
468 // and then forward. In either case, returns the new value of "compact_top". | |
469 // If the forwarding crosses "cp->threshold", invokes the "cross_threhold" | |
470 // function of the then-current compaction space, and updates "cp->threshold | |
471 // accordingly". | |
472 virtual HeapWord* forward(oop q, size_t size, CompactPoint* cp, | |
473 HeapWord* compact_top); | |
474 | |
475 // Return a size with adjusments as required of the space. | |
476 virtual size_t adjust_object_size_v(size_t size) const { return size; } | |
477 | |
478 protected: | |
479 // Used during compaction. | |
480 HeapWord* _first_dead; | |
481 HeapWord* _end_of_live; | |
482 | |
483 // Minimum size of a free block. | |
484 virtual size_t minimum_free_block_size() const = 0; | |
485 | |
486 // This the function is invoked when an allocation of an object covering | |
487 // "start" to "end occurs crosses the threshold; returns the next | |
488 // threshold. (The default implementation does nothing.) | |
489 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* the_end) { | |
490 return end(); | |
491 } | |
492 | |
493 // Requires "allowed_deadspace_words > 0", that "q" is the start of a | |
494 // free block of the given "word_len", and that "q", were it an object, | |
495 // would not move if forwared. If the size allows, fill the free | |
496 // block with an object, to prevent excessive compaction. Returns "true" | |
497 // iff the free region was made deadspace, and modifies | |
498 // "allowed_deadspace_words" to reflect the number of available deadspace | |
499 // words remaining after this operation. | |
500 bool insert_deadspace(size_t& allowed_deadspace_words, HeapWord* q, | |
501 size_t word_len); | |
502 }; | |
503 | |
504 #define SCAN_AND_FORWARD(cp,scan_limit,block_is_obj,block_size) { \ | |
505 /* Compute the new addresses for the live objects and store it in the mark \ | |
506 * Used by universe::mark_sweep_phase2() \ | |
507 */ \ | |
508 HeapWord* compact_top; /* This is where we are currently compacting to. */ \ | |
509 \ | |
510 /* We're sure to be here before any objects are compacted into this \ | |
511 * space, so this is a good time to initialize this: \ | |
512 */ \ | |
513 set_compaction_top(bottom()); \ | |
514 \ | |
515 if (cp->space == NULL) { \ | |
516 assert(cp->gen != NULL, "need a generation"); \ | |
517 assert(cp->threshold == NULL, "just checking"); \ | |
518 assert(cp->gen->first_compaction_space() == this, "just checking"); \ | |
519 cp->space = cp->gen->first_compaction_space(); \ | |
520 compact_top = cp->space->bottom(); \ | |
521 cp->space->set_compaction_top(compact_top); \ | |
522 cp->threshold = cp->space->initialize_threshold(); \ | |
523 } else { \ | |
524 compact_top = cp->space->compaction_top(); \ | |
525 } \ | |
526 \ | |
527 /* We allow some amount of garbage towards the bottom of the space, so \ | |
528 * we don't start compacting before there is a significant gain to be made.\ | |
529 * Occasionally, we want to ensure a full compaction, which is determined \ | |
530 * by the MarkSweepAlwaysCompactCount parameter. \ | |
531 */ \ | |
532 int invocations = SharedHeap::heap()->perm_gen()->stat_record()->invocations;\ | |
533 bool skip_dead = ((invocations % MarkSweepAlwaysCompactCount) != 0); \ | |
534 \ | |
535 size_t allowed_deadspace = 0; \ | |
536 if (skip_dead) { \ | |
438 | 537 const size_t ratio = allowed_dead_ratio(); \ |
0 | 538 allowed_deadspace = (capacity() * ratio / 100) / HeapWordSize; \ |
539 } \ | |
540 \ | |
541 HeapWord* q = bottom(); \ | |
542 HeapWord* t = scan_limit(); \ | |
543 \ | |
544 HeapWord* end_of_live= q; /* One byte beyond the last byte of the last \ | |
545 live object. */ \ | |
546 HeapWord* first_dead = end();/* The first dead object. */ \ | |
547 LiveRange* liveRange = NULL; /* The current live range, recorded in the \ | |
548 first header of preceding free area. */ \ | |
549 _first_dead = first_dead; \ | |
550 \ | |
551 const intx interval = PrefetchScanIntervalInBytes; \ | |
552 \ | |
553 while (q < t) { \ | |
554 assert(!block_is_obj(q) || \ | |
555 oop(q)->mark()->is_marked() || oop(q)->mark()->is_unlocked() || \ | |
556 oop(q)->mark()->has_bias_pattern(), \ | |
557 "these are the only valid states during a mark sweep"); \ | |
558 if (block_is_obj(q) && oop(q)->is_gc_marked()) { \ | |
559 /* prefetch beyond q */ \ | |
560 Prefetch::write(q, interval); \ | |
561 /* size_t size = oop(q)->size(); changing this for cms for perm gen */\ | |
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562 size_t size = block_size(q); \ |
0 | 563 compact_top = cp->space->forward(oop(q), size, cp, compact_top); \ |
564 q += size; \ | |
565 end_of_live = q; \ | |
566 } else { \ | |
567 /* run over all the contiguous dead objects */ \ | |
568 HeapWord* end = q; \ | |
569 do { \ | |
570 /* prefetch beyond end */ \ | |
571 Prefetch::write(end, interval); \ | |
572 end += block_size(end); \ | |
573 } while (end < t && (!block_is_obj(end) || !oop(end)->is_gc_marked()));\ | |
574 \ | |
575 /* see if we might want to pretend this object is alive so that \ | |
576 * we don't have to compact quite as often. \ | |
577 */ \ | |
578 if (allowed_deadspace > 0 && q == compact_top) { \ | |
579 size_t sz = pointer_delta(end, q); \ | |
580 if (insert_deadspace(allowed_deadspace, q, sz)) { \ | |
581 compact_top = cp->space->forward(oop(q), sz, cp, compact_top); \ | |
582 q = end; \ | |
583 end_of_live = end; \ | |
584 continue; \ | |
585 } \ | |
586 } \ | |
587 \ | |
588 /* otherwise, it really is a free region. */ \ | |
589 \ | |
590 /* for the previous LiveRange, record the end of the live objects. */ \ | |
591 if (liveRange) { \ | |
592 liveRange->set_end(q); \ | |
593 } \ | |
594 \ | |
595 /* record the current LiveRange object. \ | |
596 * liveRange->start() is overlaid on the mark word. \ | |
597 */ \ | |
598 liveRange = (LiveRange*)q; \ | |
599 liveRange->set_start(end); \ | |
600 liveRange->set_end(end); \ | |
601 \ | |
602 /* see if this is the first dead region. */ \ | |
603 if (q < first_dead) { \ | |
604 first_dead = q; \ | |
605 } \ | |
606 \ | |
607 /* move on to the next object */ \ | |
608 q = end; \ | |
609 } \ | |
610 } \ | |
611 \ | |
612 assert(q == t, "just checking"); \ | |
613 if (liveRange != NULL) { \ | |
614 liveRange->set_end(q); \ | |
615 } \ | |
616 _end_of_live = end_of_live; \ | |
617 if (end_of_live < first_dead) { \ | |
618 first_dead = end_of_live; \ | |
619 } \ | |
620 _first_dead = first_dead; \ | |
621 \ | |
622 /* save the compaction_top of the compaction space. */ \ | |
623 cp->space->set_compaction_top(compact_top); \ | |
624 } | |
625 | |
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626 #define SCAN_AND_ADJUST_POINTERS(adjust_obj_size) { \ |
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627 /* adjust all the interior pointers to point at the new locations of objects \ |
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628 * Used by MarkSweep::mark_sweep_phase3() */ \ |
0 | 629 \ |
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630 HeapWord* q = bottom(); \ |
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631 HeapWord* t = _end_of_live; /* Established by "prepare_for_compaction". */ \ |
0 | 632 \ |
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633 assert(_first_dead <= _end_of_live, "Stands to reason, no?"); \ |
0 | 634 \ |
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635 if (q < t && _first_dead > q && \ |
0 | 636 !oop(q)->is_gc_marked()) { \ |
637 /* we have a chunk of the space which hasn't moved and we've \ | |
638 * reinitialized the mark word during the previous pass, so we can't \ | |
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639 * use is_gc_marked for the traversal. */ \ |
0 | 640 HeapWord* end = _first_dead; \ |
641 \ | |
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642 while (q < end) { \ |
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643 /* I originally tried to conjoin "block_start(q) == q" to the \ |
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644 * assertion below, but that doesn't work, because you can't \ |
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645 * accurately traverse previous objects to get to the current one \ |
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646 * after their pointers (including pointers into permGen) have been \ |
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647 * updated, until the actual compaction is done. dld, 4/00 */ \ |
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648 assert(block_is_obj(q), \ |
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649 "should be at block boundaries, and should be looking at objs"); \ |
0 | 650 \ |
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651 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::track_interior_pointers(oop(q))); \ |
0 | 652 \ |
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653 /* point all the oops to the new location */ \ |
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654 size_t size = oop(q)->adjust_pointers(); \ |
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655 size = adjust_obj_size(size); \ |
0 | 656 \ |
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657 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::check_interior_pointers()); \ |
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658 \ |
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659 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::validate_live_oop(oop(q), size)); \ |
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660 \ |
0 | 661 q += size; \ |
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662 } \ |
0 | 663 \ |
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664 if (_first_dead == t) { \ |
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665 q = t; \ |
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666 } else { \ |
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667 /* $$$ This is funky. Using this to read the previously written \ |
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668 * LiveRange. See also use below. */ \ |
0 | 669 q = (HeapWord*)oop(_first_dead)->mark()->decode_pointer(); \ |
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670 } \ |
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671 } \ |
0 | 672 \ |
673 const intx interval = PrefetchScanIntervalInBytes; \ | |
674 \ | |
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675 debug_only(HeapWord* prev_q = NULL); \ |
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676 while (q < t) { \ |
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677 /* prefetch beyond q */ \ |
0 | 678 Prefetch::write(q, interval); \ |
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679 if (oop(q)->is_gc_marked()) { \ |
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680 /* q is alive */ \ |
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681 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::track_interior_pointers(oop(q))); \ |
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682 /* point all the oops to the new location */ \ |
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683 size_t size = oop(q)->adjust_pointers(); \ |
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684 size = adjust_obj_size(size); \ |
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685 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::check_interior_pointers()); \ |
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686 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::validate_live_oop(oop(q), size)); \ |
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687 debug_only(prev_q = q); \ |
0 | 688 q += size; \ |
356 | 689 } else { \ |
690 /* q is not a live object, so its mark should point at the next \ | |
691 * live object */ \ | |
692 debug_only(prev_q = q); \ | |
693 q = (HeapWord*) oop(q)->mark()->decode_pointer(); \ | |
694 assert(q > prev_q, "we should be moving forward through memory"); \ | |
695 } \ | |
696 } \ | |
0 | 697 \ |
356 | 698 assert(q == t, "just checking"); \ |
0 | 699 } |
700 | |
356 | 701 #define SCAN_AND_COMPACT(obj_size) { \ |
0 | 702 /* Copy all live objects to their new location \ |
356 | 703 * Used by MarkSweep::mark_sweep_phase4() */ \ |
0 | 704 \ |
356 | 705 HeapWord* q = bottom(); \ |
706 HeapWord* const t = _end_of_live; \ | |
707 debug_only(HeapWord* prev_q = NULL); \ | |
0 | 708 \ |
356 | 709 if (q < t && _first_dead > q && \ |
0 | 710 !oop(q)->is_gc_marked()) { \ |
356 | 711 debug_only( \ |
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712 /* we have a chunk of the space which hasn't moved and we've reinitialized \ |
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713 * the mark word during the previous pass, so we can't use is_gc_marked for \ |
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714 * the traversal. */ \ |
356 | 715 HeapWord* const end = _first_dead; \ |
716 \ | |
717 while (q < end) { \ | |
0 | 718 size_t size = obj_size(q); \ |
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719 assert(!oop(q)->is_gc_marked(), \ |
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720 "should be unmarked (special dense prefix handling)"); \ |
356 | 721 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::live_oop_moved_to(q, size, q)); \ |
722 debug_only(prev_q = q); \ | |
0 | 723 q += size; \ |
356 | 724 } \ |
725 ) /* debug_only */ \ | |
726 \ | |
727 if (_first_dead == t) { \ | |
728 q = t; \ | |
729 } else { \ | |
730 /* $$$ Funky */ \ | |
731 q = (HeapWord*) oop(_first_dead)->mark()->decode_pointer(); \ | |
732 } \ | |
733 } \ | |
0 | 734 \ |
356 | 735 const intx scan_interval = PrefetchScanIntervalInBytes; \ |
736 const intx copy_interval = PrefetchCopyIntervalInBytes; \ | |
737 while (q < t) { \ | |
738 if (!oop(q)->is_gc_marked()) { \ | |
739 /* mark is pointer to next marked oop */ \ | |
740 debug_only(prev_q = q); \ | |
741 q = (HeapWord*) oop(q)->mark()->decode_pointer(); \ | |
742 assert(q > prev_q, "we should be moving forward through memory"); \ | |
743 } else { \ | |
744 /* prefetch beyond q */ \ | |
0 | 745 Prefetch::read(q, scan_interval); \ |
746 \ | |
747 /* size and destination */ \ | |
748 size_t size = obj_size(q); \ | |
749 HeapWord* compaction_top = (HeapWord*)oop(q)->forwardee(); \ | |
750 \ | |
356 | 751 /* prefetch beyond compaction_top */ \ |
0 | 752 Prefetch::write(compaction_top, copy_interval); \ |
753 \ | |
356 | 754 /* copy object and reinit its mark */ \ |
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755 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::live_oop_moved_to(q, size, \ |
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756 compaction_top)); \ |
356 | 757 assert(q != compaction_top, "everything in this pass should be moving"); \ |
758 Copy::aligned_conjoint_words(q, compaction_top, size); \ | |
759 oop(compaction_top)->init_mark(); \ | |
760 assert(oop(compaction_top)->klass() != NULL, "should have a class"); \ | |
0 | 761 \ |
356 | 762 debug_only(prev_q = q); \ |
0 | 763 q += size; \ |
356 | 764 } \ |
765 } \ | |
0 | 766 \ |
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767 /* Let's remember if we were empty before we did the compaction. */ \ |
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768 bool was_empty = used_region().is_empty(); \ |
0 | 769 /* Reset space after compaction is complete */ \ |
356 | 770 reset_after_compaction(); \ |
0 | 771 /* We do this clear, below, since it has overloaded meanings for some */ \ |
772 /* space subtypes. For example, OffsetTableContigSpace's that were */ \ | |
773 /* compacted into will have had their offset table thresholds updated */ \ | |
774 /* continuously, but those that weren't need to have their thresholds */ \ | |
775 /* re-initialized. Also mangles unused area for debugging. */ \ | |
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776 if (used_region().is_empty()) { \ |
356 | 777 if (!was_empty) clear(SpaceDecorator::Mangle); \ |
0 | 778 } else { \ |
779 if (ZapUnusedHeapArea) mangle_unused_area(); \ | |
780 } \ | |
781 } | |
782 | |
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783 class GenSpaceMangler; |
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784 |
0 | 785 // A space in which the free area is contiguous. It therefore supports |
786 // faster allocation, and compaction. | |
787 class ContiguousSpace: public CompactibleSpace { | |
788 friend class OneContigSpaceCardGeneration; | |
789 friend class VMStructs; | |
790 protected: | |
791 HeapWord* _top; | |
792 HeapWord* _concurrent_iteration_safe_limit; | |
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793 // A helper for mangling the unused area of the space in debug builds. |
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794 GenSpaceMangler* _mangler; |
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795 |
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796 GenSpaceMangler* mangler() { return _mangler; } |
0 | 797 |
798 // Allocation helpers (return NULL if full). | |
799 inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value); | |
800 inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value); | |
801 | |
802 public: | |
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803 ContiguousSpace(); |
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804 ~ContiguousSpace(); |
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805 |
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806 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); |
356 | 807 virtual void clear(bool mangle_space); |
0 | 808 |
809 // Accessors | |
810 HeapWord* top() const { return _top; } | |
811 void set_top(HeapWord* value) { _top = value; } | |
812 | |
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813 virtual void set_saved_mark() { _saved_mark_word = top(); } |
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814 void reset_saved_mark() { _saved_mark_word = bottom(); } |
0 | 815 |
816 WaterMark bottom_mark() { return WaterMark(this, bottom()); } | |
817 WaterMark top_mark() { return WaterMark(this, top()); } | |
818 WaterMark saved_mark() { return WaterMark(this, saved_mark_word()); } | |
819 bool saved_mark_at_top() const { return saved_mark_word() == top(); } | |
820 | |
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821 // In debug mode mangle (write it with a particular bit |
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822 // pattern) the unused part of a space. |
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823 |
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824 // Used to save the an address in a space for later use during mangling. |
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825 void set_top_for_allocations(HeapWord* v) PRODUCT_RETURN; |
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826 // Used to save the space's current top for later use during mangling. |
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827 void set_top_for_allocations() PRODUCT_RETURN; |
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828 |
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829 // Mangle regions in the space from the current top up to the |
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830 // previously mangled part of the space. |
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831 void mangle_unused_area() PRODUCT_RETURN; |
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832 // Mangle [top, end) |
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833 void mangle_unused_area_complete() PRODUCT_RETURN; |
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834 // Mangle the given MemRegion. |
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835 void mangle_region(MemRegion mr) PRODUCT_RETURN; |
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836 |
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837 // Do some sparse checking on the area that should have been mangled. |
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838 void check_mangled_unused_area(HeapWord* limit) PRODUCT_RETURN; |
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839 // Check the complete area that should have been mangled. |
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840 // This code may be NULL depending on the macro DEBUG_MANGLING. |
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841 void check_mangled_unused_area_complete() PRODUCT_RETURN; |
0 | 842 |
843 // Size computations: sizes in bytes. | |
844 size_t capacity() const { return byte_size(bottom(), end()); } | |
845 size_t used() const { return byte_size(bottom(), top()); } | |
846 size_t free() const { return byte_size(top(), end()); } | |
847 | |
848 // Override from space. | |
849 bool is_in(const void* p) const; | |
850 | |
851 virtual bool is_free_block(const HeapWord* p) const; | |
852 | |
853 // In a contiguous space we have a more obvious bound on what parts | |
854 // contain objects. | |
855 MemRegion used_region() const { return MemRegion(bottom(), top()); } | |
856 | |
857 MemRegion used_region_at_save_marks() const { | |
858 return MemRegion(bottom(), saved_mark_word()); | |
859 } | |
860 | |
861 // Allocation (return NULL if full) | |
862 virtual HeapWord* allocate(size_t word_size); | |
863 virtual HeapWord* par_allocate(size_t word_size); | |
864 | |
865 virtual bool obj_allocated_since_save_marks(const oop obj) const { | |
866 return (HeapWord*)obj >= saved_mark_word(); | |
867 } | |
868 | |
869 // Iteration | |
870 void oop_iterate(OopClosure* cl); | |
871 void oop_iterate(MemRegion mr, OopClosure* cl); | |
872 void object_iterate(ObjectClosure* blk); | |
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873 // For contiguous spaces this method will iterate safely over objects |
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874 // in the space (i.e., between bottom and top) when at a safepoint. |
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875 void safe_object_iterate(ObjectClosure* blk); |
0 | 876 void object_iterate_mem(MemRegion mr, UpwardsObjectClosure* cl); |
877 // iterates on objects up to the safe limit | |
878 HeapWord* object_iterate_careful(ObjectClosureCareful* cl); | |
879 inline HeapWord* concurrent_iteration_safe_limit(); | |
880 // changes the safe limit, all objects from bottom() to the new | |
881 // limit should be properly initialized | |
882 inline void set_concurrent_iteration_safe_limit(HeapWord* new_limit); | |
883 | |
884 #ifndef SERIALGC | |
885 // In support of parallel oop_iterate. | |
886 #define ContigSpace_PAR_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ | |
887 void par_oop_iterate(MemRegion mr, OopClosureType* blk); | |
888 | |
889 ALL_PAR_OOP_ITERATE_CLOSURES(ContigSpace_PAR_OOP_ITERATE_DECL) | |
890 #undef ContigSpace_PAR_OOP_ITERATE_DECL | |
891 #endif // SERIALGC | |
892 | |
893 // Compaction support | |
894 virtual void reset_after_compaction() { | |
895 assert(compaction_top() >= bottom() && compaction_top() <= end(), "should point inside space"); | |
896 set_top(compaction_top()); | |
897 // set new iteration safe limit | |
898 set_concurrent_iteration_safe_limit(compaction_top()); | |
899 } | |
900 virtual size_t minimum_free_block_size() const { return 0; } | |
901 | |
902 // Override. | |
903 DirtyCardToOopClosure* new_dcto_cl(OopClosure* cl, | |
904 CardTableModRefBS::PrecisionStyle precision, | |
905 HeapWord* boundary = NULL); | |
906 | |
907 // Apply "blk->do_oop" to the addresses of all reference fields in objects | |
908 // starting with the _saved_mark_word, which was noted during a generation's | |
909 // save_marks and is required to denote the head of an object. | |
910 // Fields in objects allocated by applications of the closure | |
911 // *are* included in the iteration. | |
912 // Updates _saved_mark_word to point to just after the last object | |
913 // iterated over. | |
914 #define ContigSpace_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ | |
915 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk); | |
916 | |
917 ALL_SINCE_SAVE_MARKS_CLOSURES(ContigSpace_OOP_SINCE_SAVE_MARKS_DECL) | |
918 #undef ContigSpace_OOP_SINCE_SAVE_MARKS_DECL | |
919 | |
920 // Same as object_iterate, but starting from "mark", which is required | |
921 // to denote the start of an object. Objects allocated by | |
922 // applications of the closure *are* included in the iteration. | |
923 virtual void object_iterate_from(WaterMark mark, ObjectClosure* blk); | |
924 | |
925 // Very inefficient implementation. | |
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926 virtual HeapWord* block_start_const(const void* p) const; |
0 | 927 size_t block_size(const HeapWord* p) const; |
928 // If a block is in the allocated area, it is an object. | |
929 bool block_is_obj(const HeapWord* p) const { return p < top(); } | |
930 | |
931 // Addresses for inlined allocation | |
932 HeapWord** top_addr() { return &_top; } | |
933 HeapWord** end_addr() { return &_end; } | |
934 | |
935 // Overrides for more efficient compaction support. | |
936 void prepare_for_compaction(CompactPoint* cp); | |
937 | |
938 // PrintHeapAtGC support. | |
939 virtual void print_on(outputStream* st) const; | |
940 | |
941 // Checked dynamic downcasts. | |
942 virtual ContiguousSpace* toContiguousSpace() { | |
943 return this; | |
944 } | |
945 | |
946 // Debugging | |
947 virtual void verify(bool allow_dirty) const; | |
948 | |
949 // Used to increase collection frequency. "factor" of 0 means entire | |
950 // space. | |
951 void allocate_temporary_filler(int factor); | |
952 | |
953 }; | |
954 | |
955 | |
956 // A dirty card to oop closure that does filtering. | |
957 // It knows how to filter out objects that are outside of the _boundary. | |
958 class Filtering_DCTOC : public DirtyCardToOopClosure { | |
959 protected: | |
960 // Override. | |
961 void walk_mem_region(MemRegion mr, | |
962 HeapWord* bottom, HeapWord* top); | |
963 | |
964 // Walk the given memory region, from bottom to top, applying | |
965 // the given oop closure to (possibly) all objects found. The | |
966 // given oop closure may or may not be the same as the oop | |
967 // closure with which this closure was created, as it may | |
968 // be a filtering closure which makes use of the _boundary. | |
969 // We offer two signatures, so the FilteringClosure static type is | |
970 // apparent. | |
971 virtual void walk_mem_region_with_cl(MemRegion mr, | |
972 HeapWord* bottom, HeapWord* top, | |
973 OopClosure* cl) = 0; | |
974 virtual void walk_mem_region_with_cl(MemRegion mr, | |
975 HeapWord* bottom, HeapWord* top, | |
976 FilteringClosure* cl) = 0; | |
977 | |
978 public: | |
979 Filtering_DCTOC(Space* sp, OopClosure* cl, | |
980 CardTableModRefBS::PrecisionStyle precision, | |
981 HeapWord* boundary) : | |
982 DirtyCardToOopClosure(sp, cl, precision, boundary) {} | |
983 }; | |
984 | |
985 // A dirty card to oop closure for contiguous spaces | |
986 // (ContiguousSpace and sub-classes). | |
987 // It is a FilteringClosure, as defined above, and it knows: | |
988 // | |
989 // 1. That the actual top of any area in a memory region | |
990 // contained by the space is bounded by the end of the contiguous | |
991 // region of the space. | |
992 // 2. That the space is really made up of objects and not just | |
993 // blocks. | |
994 | |
995 class ContiguousSpaceDCTOC : public Filtering_DCTOC { | |
996 protected: | |
997 // Overrides. | |
998 HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj); | |
999 | |
1000 virtual void walk_mem_region_with_cl(MemRegion mr, | |
1001 HeapWord* bottom, HeapWord* top, | |
1002 OopClosure* cl); | |
1003 virtual void walk_mem_region_with_cl(MemRegion mr, | |
1004 HeapWord* bottom, HeapWord* top, | |
1005 FilteringClosure* cl); | |
1006 | |
1007 public: | |
1008 ContiguousSpaceDCTOC(ContiguousSpace* sp, OopClosure* cl, | |
1009 CardTableModRefBS::PrecisionStyle precision, | |
1010 HeapWord* boundary) : | |
1011 Filtering_DCTOC(sp, cl, precision, boundary) | |
1012 {} | |
1013 }; | |
1014 | |
1015 | |
1016 // Class EdenSpace describes eden-space in new generation. | |
1017 | |
1018 class DefNewGeneration; | |
1019 | |
1020 class EdenSpace : public ContiguousSpace { | |
1021 friend class VMStructs; | |
1022 private: | |
1023 DefNewGeneration* _gen; | |
1024 | |
1025 // _soft_end is used as a soft limit on allocation. As soft limits are | |
1026 // reached, the slow-path allocation code can invoke other actions and then | |
1027 // adjust _soft_end up to a new soft limit or to end(). | |
1028 HeapWord* _soft_end; | |
1029 | |
1030 public: | |
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1031 EdenSpace(DefNewGeneration* gen) : |
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1032 _gen(gen), _soft_end(NULL) {} |
0 | 1033 |
1034 // Get/set just the 'soft' limit. | |
1035 HeapWord* soft_end() { return _soft_end; } | |
1036 HeapWord** soft_end_addr() { return &_soft_end; } | |
1037 void set_soft_end(HeapWord* value) { _soft_end = value; } | |
1038 | |
1039 // Override. | |
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1040 void clear(bool mangle_space); |
0 | 1041 |
1042 // Set both the 'hard' and 'soft' limits (_end and _soft_end). | |
1043 void set_end(HeapWord* value) { | |
1044 set_soft_end(value); | |
1045 ContiguousSpace::set_end(value); | |
1046 } | |
1047 | |
1048 // Allocation (return NULL if full) | |
1049 HeapWord* allocate(size_t word_size); | |
1050 HeapWord* par_allocate(size_t word_size); | |
1051 }; | |
1052 | |
1053 // Class ConcEdenSpace extends EdenSpace for the sake of safe | |
1054 // allocation while soft-end is being modified concurrently | |
1055 | |
1056 class ConcEdenSpace : public EdenSpace { | |
1057 public: | |
1058 ConcEdenSpace(DefNewGeneration* gen) : EdenSpace(gen) { } | |
1059 | |
1060 // Allocation (return NULL if full) | |
1061 HeapWord* par_allocate(size_t word_size); | |
1062 }; | |
1063 | |
1064 | |
1065 // A ContigSpace that Supports an efficient "block_start" operation via | |
1066 // a BlockOffsetArray (whose BlockOffsetSharedArray may be shared with | |
1067 // other spaces.) This is the abstract base class for old generation | |
1068 // (tenured, perm) spaces. | |
1069 | |
1070 class OffsetTableContigSpace: public ContiguousSpace { | |
1071 friend class VMStructs; | |
1072 protected: | |
1073 BlockOffsetArrayContigSpace _offsets; | |
1074 Mutex _par_alloc_lock; | |
1075 | |
1076 public: | |
1077 // Constructor | |
1078 OffsetTableContigSpace(BlockOffsetSharedArray* sharedOffsetArray, | |
1079 MemRegion mr); | |
1080 | |
1081 void set_bottom(HeapWord* value); | |
1082 void set_end(HeapWord* value); | |
1083 | |
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1084 void clear(bool mangle_space); |
0 | 1085 |
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1086 inline HeapWord* block_start_const(const void* p) const; |
0 | 1087 |
1088 // Add offset table update. | |
1089 virtual inline HeapWord* allocate(size_t word_size); | |
1090 inline HeapWord* par_allocate(size_t word_size); | |
1091 | |
1092 // MarkSweep support phase3 | |
1093 virtual HeapWord* initialize_threshold(); | |
1094 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); | |
1095 | |
1096 virtual void print_on(outputStream* st) const; | |
1097 | |
1098 // Debugging | |
1099 void verify(bool allow_dirty) const; | |
1100 | |
1101 // Shared space support | |
1102 void serialize_block_offset_array_offsets(SerializeOopClosure* soc); | |
1103 }; | |
1104 | |
1105 | |
1106 // Class TenuredSpace is used by TenuredGeneration | |
1107 | |
1108 class TenuredSpace: public OffsetTableContigSpace { | |
1109 friend class VMStructs; | |
1110 protected: | |
1111 // Mark sweep support | |
438 | 1112 size_t allowed_dead_ratio() const; |
0 | 1113 public: |
1114 // Constructor | |
1115 TenuredSpace(BlockOffsetSharedArray* sharedOffsetArray, | |
1116 MemRegion mr) : | |
1117 OffsetTableContigSpace(sharedOffsetArray, mr) {} | |
1118 }; | |
1119 | |
1120 | |
1121 // Class ContigPermSpace is used by CompactingPermGen | |
1122 | |
1123 class ContigPermSpace: public OffsetTableContigSpace { | |
1124 friend class VMStructs; | |
1125 protected: | |
1126 // Mark sweep support | |
438 | 1127 size_t allowed_dead_ratio() const; |
0 | 1128 public: |
1129 // Constructor | |
1130 ContigPermSpace(BlockOffsetSharedArray* sharedOffsetArray, MemRegion mr) : | |
1131 OffsetTableContigSpace(sharedOffsetArray, mr) {} | |
1132 }; | |
1972 | 1133 |
1134 #endif // SHARE_VM_MEMORY_SPACE_HPP |