Mercurial > hg > truffle
annotate src/share/vm/memory/space.hpp @ 20413:91cb3b8aac2b
8048879: "unexpected yanked node" opto/postaloc.cpp:139
Summary: MemBarAcquireNode prevents deletion of dead LoadNNode. Added condition to 'has_special_unique_user' to trigger deletion.
Reviewed-by: kvn, iveresov
author | thartmann |
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date | Tue, 19 Aug 2014 07:36:11 +0200 |
parents | ee019285a52c |
children | d35872270666 |
rev | line source |
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0 | 1 /* |
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2 * Copyright (c) 1997, 2013, 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" | |
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36 #include "utilities/macros.hpp" |
1972 | 37 #include "utilities/workgroup.hpp" |
38 | |
0 | 39 // A space is an abstraction for the "storage units" backing |
40 // up the generation abstraction. It includes specific | |
41 // implementations for keeping track of free and used space, | |
42 // for iterating over objects and free blocks, etc. | |
43 | |
44 // Here's the Space hierarchy: | |
45 // | |
46 // - Space -- an asbtract base class describing a heap area | |
47 // - CompactibleSpace -- a space supporting compaction | |
48 // - CompactibleFreeListSpace -- (used for CMS generation) | |
49 // - ContiguousSpace -- a compactible space in which all free space | |
50 // is contiguous | |
51 // - EdenSpace -- contiguous space used as nursery | |
52 // - ConcEdenSpace -- contiguous space with a 'soft end safe' allocation | |
53 // - OffsetTableContigSpace -- contiguous space with a block offset array | |
54 // that allows "fast" block_start calls | |
55 // - TenuredSpace -- (used for TenuredGeneration) | |
56 | |
57 // Forward decls. | |
58 class Space; | |
59 class BlockOffsetArray; | |
60 class BlockOffsetArrayContigSpace; | |
61 class Generation; | |
62 class CompactibleSpace; | |
63 class BlockOffsetTable; | |
64 class GenRemSet; | |
65 class CardTableRS; | |
66 class DirtyCardToOopClosure; | |
67 | |
68 // A Space describes a heap area. Class Space is an abstract | |
69 // base class. | |
70 // | |
71 // Space supports allocation, size computation and GC support is provided. | |
72 // | |
73 // Invariant: bottom() and end() are on page_size boundaries and | |
74 // bottom() <= top() <= end() | |
75 // top() is inclusive and end() is exclusive. | |
76 | |
6197 | 77 class Space: public CHeapObj<mtGC> { |
0 | 78 friend class VMStructs; |
79 protected: | |
80 HeapWord* _bottom; | |
81 HeapWord* _end; | |
82 | |
83 // Used in support of save_marks() | |
84 HeapWord* _saved_mark_word; | |
85 | |
86 MemRegionClosure* _preconsumptionDirtyCardClosure; | |
87 | |
88 // A sequential tasks done structure. This supports | |
89 // parallel GC, where we have threads dynamically | |
90 // claiming sub-tasks from a larger parallel task. | |
91 SequentialSubTasksDone _par_seq_tasks; | |
92 | |
93 Space(): | |
94 _bottom(NULL), _end(NULL), _preconsumptionDirtyCardClosure(NULL) { } | |
95 | |
96 public: | |
97 // Accessors | |
98 HeapWord* bottom() const { return _bottom; } | |
99 HeapWord* end() const { return _end; } | |
100 virtual void set_bottom(HeapWord* value) { _bottom = value; } | |
101 virtual void set_end(HeapWord* value) { _end = value; } | |
102 | |
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103 virtual HeapWord* saved_mark_word() const { return _saved_mark_word; } |
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104 |
0 | 105 void set_saved_mark_word(HeapWord* p) { _saved_mark_word = p; } |
106 | |
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107 // Returns true if this object has been allocated since a |
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108 // generation's "save_marks" call. |
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109 virtual bool obj_allocated_since_save_marks(const oop obj) const { |
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110 return (HeapWord*)obj >= saved_mark_word(); |
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111 } |
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112 |
0 | 113 MemRegionClosure* preconsumptionDirtyCardClosure() const { |
114 return _preconsumptionDirtyCardClosure; | |
115 } | |
116 void setPreconsumptionDirtyCardClosure(MemRegionClosure* cl) { | |
117 _preconsumptionDirtyCardClosure = cl; | |
118 } | |
119 | |
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120 // Returns a subregion of the space containing only the allocated objects in |
0 | 121 // the space. |
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122 virtual MemRegion used_region() const = 0; |
0 | 123 |
124 // Returns a region that is guaranteed to contain (at least) all objects | |
125 // allocated at the time of the last call to "save_marks". If the space | |
126 // initializes its DirtyCardToOopClosure's specifying the "contig" option | |
127 // (that is, if the space is contiguous), then this region must contain only | |
128 // such objects: the memregion will be from the bottom of the region to the | |
129 // saved mark. Otherwise, the "obj_allocated_since_save_marks" method of | |
130 // the space must distiguish between objects in the region allocated before | |
131 // and after the call to save marks. | |
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132 MemRegion used_region_at_save_marks() const { |
0 | 133 return MemRegion(bottom(), saved_mark_word()); |
134 } | |
135 | |
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136 // Initialization. |
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137 // "initialize" should be called once on a space, before it is used for |
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138 // any purpose. The "mr" arguments gives the bounds of the space, and |
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139 // the "clear_space" argument should be true unless the memory in "mr" is |
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140 // known to be zeroed. |
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141 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); |
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142 |
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143 // The "clear" method must be called on a region that may have |
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144 // had allocation performed in it, but is now to be considered empty. |
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145 virtual void clear(bool mangle_space); |
0 | 146 |
147 // For detecting GC bugs. Should only be called at GC boundaries, since | |
148 // some unused space may be used as scratch space during GC's. | |
149 // Default implementation does nothing. We also call this when expanding | |
150 // a space to satisfy an allocation request. See bug #4668531 | |
151 virtual void mangle_unused_area() {} | |
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152 virtual void mangle_unused_area_complete() {} |
0 | 153 virtual void mangle_region(MemRegion mr) {} |
154 | |
155 // Testers | |
156 bool is_empty() const { return used() == 0; } | |
157 bool not_empty() const { return used() > 0; } | |
158 | |
159 // Returns true iff the given the space contains the | |
160 // given address as part of an allocated object. For | |
161 // ceratin kinds of spaces, this might be a potentially | |
162 // expensive operation. To prevent performance problems | |
163 // on account of its inadvertent use in product jvm's, | |
164 // we restrict its use to assertion checks only. | |
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165 bool is_in(const void* p) const { |
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166 return used_region().contains(p); |
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167 } |
0 | 168 |
169 // Returns true iff the given reserved memory of the space contains the | |
170 // given address. | |
171 bool is_in_reserved(const void* p) const { return _bottom <= p && p < _end; } | |
172 | |
173 // Returns true iff the given block is not allocated. | |
174 virtual bool is_free_block(const HeapWord* p) const = 0; | |
175 | |
176 // Test whether p is double-aligned | |
177 static bool is_aligned(void* p) { | |
178 return ((intptr_t)p & (sizeof(double)-1)) == 0; | |
179 } | |
180 | |
181 // Size computations. Sizes are in bytes. | |
182 size_t capacity() const { return byte_size(bottom(), end()); } | |
183 virtual size_t used() const = 0; | |
184 virtual size_t free() const = 0; | |
185 | |
186 // Iterate over all the ref-containing fields of all objects in the | |
187 // space, calling "cl.do_oop" on each. Fields in objects allocated by | |
188 // applications of the closure are not included in the iteration. | |
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189 virtual void oop_iterate(ExtendedOopClosure* cl); |
0 | 190 |
191 // Iterate over all objects in the space, calling "cl.do_object" on | |
192 // each. Objects allocated by applications of the closure are not | |
193 // included in the iteration. | |
194 virtual void object_iterate(ObjectClosure* blk) = 0; | |
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195 // Similar to object_iterate() except only iterates over |
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196 // objects whose internal references point to objects in the space. |
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197 virtual void safe_object_iterate(ObjectClosure* blk) = 0; |
0 | 198 |
199 // Create and return a new dirty card to oop closure. Can be | |
200 // overriden to return the appropriate type of closure | |
201 // depending on the type of space in which the closure will | |
202 // operate. ResourceArea allocated. | |
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203 virtual DirtyCardToOopClosure* new_dcto_cl(ExtendedOopClosure* cl, |
0 | 204 CardTableModRefBS::PrecisionStyle precision, |
205 HeapWord* boundary = NULL); | |
206 | |
207 // If "p" is in the space, returns the address of the start of the | |
208 // "block" that contains "p". We say "block" instead of "object" since | |
209 // some heaps may not pack objects densely; a chunk may either be an | |
210 // object or a non-object. If "p" is not in the space, return NULL. | |
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211 virtual HeapWord* block_start_const(const void* p) const = 0; |
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212 |
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213 // The non-const version may have benevolent side effects on the data |
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214 // structure supporting these calls, possibly speeding up future calls. |
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215 // The default implementation, however, is simply to call the const |
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216 // version. |
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217 inline virtual HeapWord* block_start(const void* p); |
0 | 218 |
219 // Requires "addr" to be the start of a chunk, and returns its size. | |
220 // "addr + size" is required to be the start of a new chunk, or the end | |
221 // of the active area of the heap. | |
222 virtual size_t block_size(const HeapWord* addr) const = 0; | |
223 | |
224 // Requires "addr" to be the start of a block, and returns "TRUE" iff | |
225 // the block is an object. | |
226 virtual bool block_is_obj(const HeapWord* addr) const = 0; | |
227 | |
228 // Requires "addr" to be the start of a block, and returns "TRUE" iff | |
229 // the block is an object and the object is alive. | |
230 virtual bool obj_is_alive(const HeapWord* addr) const; | |
231 | |
232 // Allocation (return NULL if full). Assumes the caller has established | |
233 // mutually exclusive access to the space. | |
234 virtual HeapWord* allocate(size_t word_size) = 0; | |
235 | |
236 // Allocation (return NULL if full). Enforces mutual exclusion internally. | |
237 virtual HeapWord* par_allocate(size_t word_size) = 0; | |
238 | |
239 // Mark-sweep-compact support: all spaces can update pointers to objects | |
240 // moving as a part of compaction. | |
241 virtual void adjust_pointers(); | |
242 | |
243 // PrintHeapAtGC support | |
244 virtual void print() const; | |
245 virtual void print_on(outputStream* st) const; | |
246 virtual void print_short() const; | |
247 virtual void print_short_on(outputStream* st) const; | |
248 | |
249 | |
250 // Accessor for parallel sequential tasks. | |
251 SequentialSubTasksDone* par_seq_tasks() { return &_par_seq_tasks; } | |
252 | |
253 // IF "this" is a ContiguousSpace, return it, else return NULL. | |
254 virtual ContiguousSpace* toContiguousSpace() { | |
255 return NULL; | |
256 } | |
257 | |
258 // Debugging | |
6008 | 259 virtual void verify() const = 0; |
0 | 260 }; |
261 | |
262 // A MemRegionClosure (ResourceObj) whose "do_MemRegion" function applies an | |
263 // OopClosure to (the addresses of) all the ref-containing fields that could | |
264 // be modified by virtue of the given MemRegion being dirty. (Note that | |
265 // because of the imprecise nature of the write barrier, this may iterate | |
266 // over oops beyond the region.) | |
267 // This base type for dirty card to oop closures handles memory regions | |
268 // in non-contiguous spaces with no boundaries, and should be sub-classed | |
269 // to support other space types. See ContiguousDCTOC for a sub-class | |
270 // that works with ContiguousSpaces. | |
271 | |
272 class DirtyCardToOopClosure: public MemRegionClosureRO { | |
273 protected: | |
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274 ExtendedOopClosure* _cl; |
0 | 275 Space* _sp; |
276 CardTableModRefBS::PrecisionStyle _precision; | |
277 HeapWord* _boundary; // If non-NULL, process only non-NULL oops | |
278 // pointing below boundary. | |
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279 HeapWord* _min_done; // ObjHeadPreciseArray precision requires |
0 | 280 // a downwards traversal; this is the |
281 // lowest location already done (or, | |
282 // alternatively, the lowest address that | |
283 // shouldn't be done again. NULL means infinity.) | |
284 NOT_PRODUCT(HeapWord* _last_bottom;) | |
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285 NOT_PRODUCT(HeapWord* _last_explicit_min_done;) |
0 | 286 |
287 // Get the actual top of the area on which the closure will | |
288 // operate, given where the top is assumed to be (the end of the | |
289 // memory region passed to do_MemRegion) and where the object | |
290 // at the top is assumed to start. For example, an object may | |
291 // start at the top but actually extend past the assumed top, | |
292 // in which case the top becomes the end of the object. | |
293 virtual HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj); | |
294 | |
295 // Walk the given memory region from bottom to (actual) top | |
296 // looking for objects and applying the oop closure (_cl) to | |
297 // them. The base implementation of this treats the area as | |
298 // blocks, where a block may or may not be an object. Sub- | |
299 // classes should override this to provide more accurate | |
300 // or possibly more efficient walking. | |
301 virtual void walk_mem_region(MemRegion mr, HeapWord* bottom, HeapWord* top); | |
302 | |
303 public: | |
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304 DirtyCardToOopClosure(Space* sp, ExtendedOopClosure* cl, |
0 | 305 CardTableModRefBS::PrecisionStyle precision, |
306 HeapWord* boundary) : | |
307 _sp(sp), _cl(cl), _precision(precision), _boundary(boundary), | |
308 _min_done(NULL) { | |
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309 NOT_PRODUCT(_last_bottom = NULL); |
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310 NOT_PRODUCT(_last_explicit_min_done = NULL); |
0 | 311 } |
312 | |
313 void do_MemRegion(MemRegion mr); | |
314 | |
315 void set_min_done(HeapWord* min_done) { | |
316 _min_done = min_done; | |
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317 NOT_PRODUCT(_last_explicit_min_done = _min_done); |
0 | 318 } |
319 #ifndef PRODUCT | |
320 void set_last_bottom(HeapWord* last_bottom) { | |
321 _last_bottom = last_bottom; | |
322 } | |
323 #endif | |
324 }; | |
325 | |
326 // A structure to represent a point at which objects are being copied | |
327 // during compaction. | |
328 class CompactPoint : public StackObj { | |
329 public: | |
330 Generation* gen; | |
331 CompactibleSpace* space; | |
332 HeapWord* threshold; | |
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333 |
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334 CompactPoint(Generation* _gen) : |
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335 gen(_gen), space(NULL), threshold(0) {} |
0 | 336 }; |
337 | |
338 | |
339 // A space that supports compaction operations. This is usually, but not | |
340 // necessarily, a space that is normally contiguous. But, for example, a | |
341 // free-list-based space whose normal collection is a mark-sweep without | |
342 // compaction could still support compaction in full GC's. | |
343 | |
344 class CompactibleSpace: public Space { | |
345 friend class VMStructs; | |
346 friend class CompactibleFreeListSpace; | |
347 private: | |
348 HeapWord* _compaction_top; | |
349 CompactibleSpace* _next_compaction_space; | |
350 | |
351 public: | |
347
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352 CompactibleSpace() : |
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353 _compaction_top(NULL), _next_compaction_space(NULL) {} |
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354 |
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355 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); |
356 | 356 virtual void clear(bool mangle_space); |
0 | 357 |
358 // Used temporarily during a compaction phase to hold the value | |
359 // top should have when compaction is complete. | |
360 HeapWord* compaction_top() const { return _compaction_top; } | |
361 | |
362 void set_compaction_top(HeapWord* value) { | |
363 assert(value == NULL || (value >= bottom() && value <= end()), | |
364 "should point inside space"); | |
365 _compaction_top = value; | |
366 } | |
367 | |
368 // Perform operations on the space needed after a compaction | |
369 // has been performed. | |
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370 virtual void reset_after_compaction() = 0; |
0 | 371 |
372 // Returns the next space (in the current generation) to be compacted in | |
373 // the global compaction order. Also is used to select the next | |
374 // space into which to compact. | |
375 | |
376 virtual CompactibleSpace* next_compaction_space() const { | |
377 return _next_compaction_space; | |
378 } | |
379 | |
380 void set_next_compaction_space(CompactibleSpace* csp) { | |
381 _next_compaction_space = csp; | |
382 } | |
383 | |
384 // MarkSweep support phase2 | |
385 | |
386 // Start the process of compaction of the current space: compute | |
387 // post-compaction addresses, and insert forwarding pointers. The fields | |
388 // "cp->gen" and "cp->compaction_space" are the generation and space into | |
389 // which we are currently compacting. This call updates "cp" as necessary, | |
390 // and leaves the "compaction_top" of the final value of | |
391 // "cp->compaction_space" up-to-date. Offset tables may be updated in | |
392 // this phase as if the final copy had occurred; if so, "cp->threshold" | |
393 // indicates when the next such action should be taken. | |
394 virtual void prepare_for_compaction(CompactPoint* cp); | |
395 // MarkSweep support phase3 | |
396 virtual void adjust_pointers(); | |
397 // MarkSweep support phase4 | |
398 virtual void compact(); | |
399 | |
400 // The maximum percentage of objects that can be dead in the compacted | |
401 // live part of a compacted space ("deadwood" support.) | |
438 | 402 virtual size_t allowed_dead_ratio() const { return 0; }; |
0 | 403 |
404 // Some contiguous spaces may maintain some data structures that should | |
405 // be updated whenever an allocation crosses a boundary. This function | |
406 // returns the first such boundary. | |
407 // (The default implementation returns the end of the space, so the | |
408 // boundary is never crossed.) | |
409 virtual HeapWord* initialize_threshold() { return end(); } | |
410 | |
411 // "q" is an object of the given "size" that should be forwarded; | |
412 // "cp" names the generation ("gen") and containing "this" (which must | |
413 // also equal "cp->space"). "compact_top" is where in "this" the | |
414 // next object should be forwarded to. If there is room in "this" for | |
415 // the object, insert an appropriate forwarding pointer in "q". | |
416 // If not, go to the next compaction space (there must | |
417 // be one, since compaction must succeed -- we go to the first space of | |
418 // the previous generation if necessary, updating "cp"), reset compact_top | |
419 // and then forward. In either case, returns the new value of "compact_top". | |
420 // If the forwarding crosses "cp->threshold", invokes the "cross_threhold" | |
421 // function of the then-current compaction space, and updates "cp->threshold | |
422 // accordingly". | |
423 virtual HeapWord* forward(oop q, size_t size, CompactPoint* cp, | |
424 HeapWord* compact_top); | |
425 | |
426 // Return a size with adjusments as required of the space. | |
427 virtual size_t adjust_object_size_v(size_t size) const { return size; } | |
428 | |
429 protected: | |
430 // Used during compaction. | |
431 HeapWord* _first_dead; | |
432 HeapWord* _end_of_live; | |
433 | |
434 // Minimum size of a free block. | |
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435 virtual size_t minimum_free_block_size() const { return 0; } |
0 | 436 |
437 // This the function is invoked when an allocation of an object covering | |
438 // "start" to "end occurs crosses the threshold; returns the next | |
439 // threshold. (The default implementation does nothing.) | |
440 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* the_end) { | |
441 return end(); | |
442 } | |
443 | |
444 // Requires "allowed_deadspace_words > 0", that "q" is the start of a | |
445 // free block of the given "word_len", and that "q", were it an object, | |
446 // would not move if forwared. If the size allows, fill the free | |
447 // block with an object, to prevent excessive compaction. Returns "true" | |
448 // iff the free region was made deadspace, and modifies | |
449 // "allowed_deadspace_words" to reflect the number of available deadspace | |
450 // words remaining after this operation. | |
451 bool insert_deadspace(size_t& allowed_deadspace_words, HeapWord* q, | |
452 size_t word_len); | |
453 }; | |
454 | |
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455 class GenSpaceMangler; |
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456 |
0 | 457 // A space in which the free area is contiguous. It therefore supports |
458 // faster allocation, and compaction. | |
459 class ContiguousSpace: public CompactibleSpace { | |
460 friend class OneContigSpaceCardGeneration; | |
461 friend class VMStructs; | |
462 protected: | |
463 HeapWord* _top; | |
464 HeapWord* _concurrent_iteration_safe_limit; | |
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465 // A helper for mangling the unused area of the space in debug builds. |
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466 GenSpaceMangler* _mangler; |
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467 |
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468 GenSpaceMangler* mangler() { return _mangler; } |
0 | 469 |
470 // Allocation helpers (return NULL if full). | |
471 inline HeapWord* allocate_impl(size_t word_size, HeapWord* end_value); | |
472 inline HeapWord* par_allocate_impl(size_t word_size, HeapWord* end_value); | |
473 | |
474 public: | |
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475 ContiguousSpace(); |
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476 ~ContiguousSpace(); |
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477 |
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478 virtual void initialize(MemRegion mr, bool clear_space, bool mangle_space); |
356 | 479 virtual void clear(bool mangle_space); |
0 | 480 |
481 // Accessors | |
482 HeapWord* top() const { return _top; } | |
483 void set_top(HeapWord* value) { _top = value; } | |
484 | |
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485 void set_saved_mark() { _saved_mark_word = top(); } |
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486 void reset_saved_mark() { _saved_mark_word = bottom(); } |
0 | 487 |
488 WaterMark bottom_mark() { return WaterMark(this, bottom()); } | |
489 WaterMark top_mark() { return WaterMark(this, top()); } | |
490 WaterMark saved_mark() { return WaterMark(this, saved_mark_word()); } | |
491 bool saved_mark_at_top() const { return saved_mark_word() == top(); } | |
492 | |
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493 // In debug mode mangle (write it with a particular bit |
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494 // pattern) the unused part of a space. |
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495 |
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496 // Used to save the an address in a space for later use during mangling. |
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497 void set_top_for_allocations(HeapWord* v) PRODUCT_RETURN; |
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498 // Used to save the space's current top for later use during mangling. |
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499 void set_top_for_allocations() PRODUCT_RETURN; |
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500 |
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501 // Mangle regions in the space from the current top up to the |
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502 // previously mangled part of the space. |
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503 void mangle_unused_area() PRODUCT_RETURN; |
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504 // Mangle [top, end) |
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505 void mangle_unused_area_complete() PRODUCT_RETURN; |
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506 // Mangle the given MemRegion. |
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507 void mangle_region(MemRegion mr) PRODUCT_RETURN; |
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508 |
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509 // Do some sparse checking on the area that should have been mangled. |
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510 void check_mangled_unused_area(HeapWord* limit) PRODUCT_RETURN; |
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511 // Check the complete area that should have been mangled. |
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512 // This code may be NULL depending on the macro DEBUG_MANGLING. |
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513 void check_mangled_unused_area_complete() PRODUCT_RETURN; |
0 | 514 |
515 // Size computations: sizes in bytes. | |
516 size_t capacity() const { return byte_size(bottom(), end()); } | |
517 size_t used() const { return byte_size(bottom(), top()); } | |
518 size_t free() const { return byte_size(top(), end()); } | |
519 | |
520 virtual bool is_free_block(const HeapWord* p) const; | |
521 | |
522 // In a contiguous space we have a more obvious bound on what parts | |
523 // contain objects. | |
524 MemRegion used_region() const { return MemRegion(bottom(), top()); } | |
525 | |
526 // Allocation (return NULL if full) | |
527 virtual HeapWord* allocate(size_t word_size); | |
528 virtual HeapWord* par_allocate(size_t word_size); | |
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529 HeapWord* allocate_aligned(size_t word_size); |
0 | 530 |
531 // Iteration | |
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532 void oop_iterate(ExtendedOopClosure* cl); |
0 | 533 void object_iterate(ObjectClosure* blk); |
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534 // For contiguous spaces this method will iterate safely over objects |
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535 // in the space (i.e., between bottom and top) when at a safepoint. |
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536 void safe_object_iterate(ObjectClosure* blk); |
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537 |
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538 // Iterate over as many initialized objects in the space as possible, |
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539 // calling "cl.do_object_careful" on each. Return NULL if all objects |
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540 // in the space (at the start of the iteration) were iterated over. |
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541 // Return an address indicating the extent of the iteration in the |
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542 // event that the iteration had to return because of finding an |
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543 // uninitialized object in the space, or if the closure "cl" |
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544 // signaled early termination. |
0 | 545 HeapWord* object_iterate_careful(ObjectClosureCareful* cl); |
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546 HeapWord* concurrent_iteration_safe_limit() { |
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547 assert(_concurrent_iteration_safe_limit <= top(), |
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548 "_concurrent_iteration_safe_limit update missed"); |
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549 return _concurrent_iteration_safe_limit; |
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550 } |
0 | 551 // changes the safe limit, all objects from bottom() to the new |
552 // limit should be properly initialized | |
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553 void set_concurrent_iteration_safe_limit(HeapWord* new_limit) { |
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554 assert(new_limit <= top(), "uninitialized objects in the safe range"); |
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555 _concurrent_iteration_safe_limit = new_limit; |
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556 } |
0 | 557 |
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558 |
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559 #if INCLUDE_ALL_GCS |
0 | 560 // In support of parallel oop_iterate. |
561 #define ContigSpace_PAR_OOP_ITERATE_DECL(OopClosureType, nv_suffix) \ | |
562 void par_oop_iterate(MemRegion mr, OopClosureType* blk); | |
563 | |
564 ALL_PAR_OOP_ITERATE_CLOSURES(ContigSpace_PAR_OOP_ITERATE_DECL) | |
565 #undef ContigSpace_PAR_OOP_ITERATE_DECL | |
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566 #endif // INCLUDE_ALL_GCS |
0 | 567 |
568 // Compaction support | |
569 virtual void reset_after_compaction() { | |
570 assert(compaction_top() >= bottom() && compaction_top() <= end(), "should point inside space"); | |
571 set_top(compaction_top()); | |
572 // set new iteration safe limit | |
573 set_concurrent_iteration_safe_limit(compaction_top()); | |
574 } | |
575 | |
576 // Override. | |
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577 DirtyCardToOopClosure* new_dcto_cl(ExtendedOopClosure* cl, |
0 | 578 CardTableModRefBS::PrecisionStyle precision, |
579 HeapWord* boundary = NULL); | |
580 | |
581 // Apply "blk->do_oop" to the addresses of all reference fields in objects | |
582 // starting with the _saved_mark_word, which was noted during a generation's | |
583 // save_marks and is required to denote the head of an object. | |
584 // Fields in objects allocated by applications of the closure | |
585 // *are* included in the iteration. | |
586 // Updates _saved_mark_word to point to just after the last object | |
587 // iterated over. | |
588 #define ContigSpace_OOP_SINCE_SAVE_MARKS_DECL(OopClosureType, nv_suffix) \ | |
589 void oop_since_save_marks_iterate##nv_suffix(OopClosureType* blk); | |
590 | |
591 ALL_SINCE_SAVE_MARKS_CLOSURES(ContigSpace_OOP_SINCE_SAVE_MARKS_DECL) | |
592 #undef ContigSpace_OOP_SINCE_SAVE_MARKS_DECL | |
593 | |
594 // Same as object_iterate, but starting from "mark", which is required | |
595 // to denote the start of an object. Objects allocated by | |
596 // applications of the closure *are* included in the iteration. | |
597 virtual void object_iterate_from(WaterMark mark, ObjectClosure* blk); | |
598 | |
599 // Very inefficient implementation. | |
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600 virtual HeapWord* block_start_const(const void* p) const; |
0 | 601 size_t block_size(const HeapWord* p) const; |
602 // If a block is in the allocated area, it is an object. | |
603 bool block_is_obj(const HeapWord* p) const { return p < top(); } | |
604 | |
605 // Addresses for inlined allocation | |
606 HeapWord** top_addr() { return &_top; } | |
607 HeapWord** end_addr() { return &_end; } | |
608 | |
609 // Overrides for more efficient compaction support. | |
610 void prepare_for_compaction(CompactPoint* cp); | |
611 | |
612 // PrintHeapAtGC support. | |
613 virtual void print_on(outputStream* st) const; | |
614 | |
615 // Checked dynamic downcasts. | |
616 virtual ContiguousSpace* toContiguousSpace() { | |
617 return this; | |
618 } | |
619 | |
620 // Debugging | |
6008 | 621 virtual void verify() const; |
0 | 622 |
623 // Used to increase collection frequency. "factor" of 0 means entire | |
624 // space. | |
625 void allocate_temporary_filler(int factor); | |
626 | |
627 }; | |
628 | |
629 | |
630 // A dirty card to oop closure that does filtering. | |
631 // It knows how to filter out objects that are outside of the _boundary. | |
632 class Filtering_DCTOC : public DirtyCardToOopClosure { | |
633 protected: | |
634 // Override. | |
635 void walk_mem_region(MemRegion mr, | |
636 HeapWord* bottom, HeapWord* top); | |
637 | |
638 // Walk the given memory region, from bottom to top, applying | |
639 // the given oop closure to (possibly) all objects found. The | |
640 // given oop closure may or may not be the same as the oop | |
641 // closure with which this closure was created, as it may | |
642 // be a filtering closure which makes use of the _boundary. | |
643 // We offer two signatures, so the FilteringClosure static type is | |
644 // apparent. | |
645 virtual void walk_mem_region_with_cl(MemRegion mr, | |
646 HeapWord* bottom, HeapWord* top, | |
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647 ExtendedOopClosure* cl) = 0; |
0 | 648 virtual void walk_mem_region_with_cl(MemRegion mr, |
649 HeapWord* bottom, HeapWord* top, | |
650 FilteringClosure* cl) = 0; | |
651 | |
652 public: | |
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653 Filtering_DCTOC(Space* sp, ExtendedOopClosure* cl, |
0 | 654 CardTableModRefBS::PrecisionStyle precision, |
655 HeapWord* boundary) : | |
656 DirtyCardToOopClosure(sp, cl, precision, boundary) {} | |
657 }; | |
658 | |
659 // A dirty card to oop closure for contiguous spaces | |
660 // (ContiguousSpace and sub-classes). | |
661 // It is a FilteringClosure, as defined above, and it knows: | |
662 // | |
663 // 1. That the actual top of any area in a memory region | |
664 // contained by the space is bounded by the end of the contiguous | |
665 // region of the space. | |
666 // 2. That the space is really made up of objects and not just | |
667 // blocks. | |
668 | |
669 class ContiguousSpaceDCTOC : public Filtering_DCTOC { | |
670 protected: | |
671 // Overrides. | |
672 HeapWord* get_actual_top(HeapWord* top, HeapWord* top_obj); | |
673 | |
674 virtual void walk_mem_region_with_cl(MemRegion mr, | |
675 HeapWord* bottom, HeapWord* top, | |
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676 ExtendedOopClosure* cl); |
0 | 677 virtual void walk_mem_region_with_cl(MemRegion mr, |
678 HeapWord* bottom, HeapWord* top, | |
679 FilteringClosure* cl); | |
680 | |
681 public: | |
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682 ContiguousSpaceDCTOC(ContiguousSpace* sp, ExtendedOopClosure* cl, |
0 | 683 CardTableModRefBS::PrecisionStyle precision, |
684 HeapWord* boundary) : | |
685 Filtering_DCTOC(sp, cl, precision, boundary) | |
686 {} | |
687 }; | |
688 | |
689 | |
690 // Class EdenSpace describes eden-space in new generation. | |
691 | |
692 class DefNewGeneration; | |
693 | |
694 class EdenSpace : public ContiguousSpace { | |
695 friend class VMStructs; | |
696 private: | |
697 DefNewGeneration* _gen; | |
698 | |
699 // _soft_end is used as a soft limit on allocation. As soft limits are | |
700 // reached, the slow-path allocation code can invoke other actions and then | |
701 // adjust _soft_end up to a new soft limit or to end(). | |
702 HeapWord* _soft_end; | |
703 | |
704 public: | |
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705 EdenSpace(DefNewGeneration* gen) : |
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706 _gen(gen), _soft_end(NULL) {} |
0 | 707 |
708 // Get/set just the 'soft' limit. | |
709 HeapWord* soft_end() { return _soft_end; } | |
710 HeapWord** soft_end_addr() { return &_soft_end; } | |
711 void set_soft_end(HeapWord* value) { _soft_end = value; } | |
712 | |
713 // Override. | |
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714 void clear(bool mangle_space); |
0 | 715 |
716 // Set both the 'hard' and 'soft' limits (_end and _soft_end). | |
717 void set_end(HeapWord* value) { | |
718 set_soft_end(value); | |
719 ContiguousSpace::set_end(value); | |
720 } | |
721 | |
722 // Allocation (return NULL if full) | |
723 HeapWord* allocate(size_t word_size); | |
724 HeapWord* par_allocate(size_t word_size); | |
725 }; | |
726 | |
727 // Class ConcEdenSpace extends EdenSpace for the sake of safe | |
728 // allocation while soft-end is being modified concurrently | |
729 | |
730 class ConcEdenSpace : public EdenSpace { | |
731 public: | |
732 ConcEdenSpace(DefNewGeneration* gen) : EdenSpace(gen) { } | |
733 | |
734 // Allocation (return NULL if full) | |
735 HeapWord* par_allocate(size_t word_size); | |
736 }; | |
737 | |
738 | |
739 // A ContigSpace that Supports an efficient "block_start" operation via | |
740 // a BlockOffsetArray (whose BlockOffsetSharedArray may be shared with | |
741 // other spaces.) This is the abstract base class for old generation | |
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742 // (tenured) spaces. |
0 | 743 |
744 class OffsetTableContigSpace: public ContiguousSpace { | |
745 friend class VMStructs; | |
746 protected: | |
747 BlockOffsetArrayContigSpace _offsets; | |
748 Mutex _par_alloc_lock; | |
749 | |
750 public: | |
751 // Constructor | |
752 OffsetTableContigSpace(BlockOffsetSharedArray* sharedOffsetArray, | |
753 MemRegion mr); | |
754 | |
755 void set_bottom(HeapWord* value); | |
756 void set_end(HeapWord* value); | |
757 | |
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758 void clear(bool mangle_space); |
0 | 759 |
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760 inline HeapWord* block_start_const(const void* p) const; |
0 | 761 |
762 // Add offset table update. | |
763 virtual inline HeapWord* allocate(size_t word_size); | |
764 inline HeapWord* par_allocate(size_t word_size); | |
765 | |
766 // MarkSweep support phase3 | |
767 virtual HeapWord* initialize_threshold(); | |
768 virtual HeapWord* cross_threshold(HeapWord* start, HeapWord* end); | |
769 | |
770 virtual void print_on(outputStream* st) const; | |
771 | |
772 // Debugging | |
6008 | 773 void verify() const; |
0 | 774 }; |
775 | |
776 | |
777 // Class TenuredSpace is used by TenuredGeneration | |
778 | |
779 class TenuredSpace: public OffsetTableContigSpace { | |
780 friend class VMStructs; | |
781 protected: | |
782 // Mark sweep support | |
438 | 783 size_t allowed_dead_ratio() const; |
0 | 784 public: |
785 // Constructor | |
786 TenuredSpace(BlockOffsetSharedArray* sharedOffsetArray, | |
787 MemRegion mr) : | |
788 OffsetTableContigSpace(sharedOffsetArray, mr) {} | |
789 }; | |
1972 | 790 #endif // SHARE_VM_MEMORY_SPACE_HPP |