Mercurial > hg > graal-compiler
annotate src/share/vm/gc_implementation/g1/g1BlockOffsetTable.hpp @ 20795:ae52ee069062
8062063: Usage of UseHugeTLBFS, UseLargePagesInMetaspace and huge SurvivorAlignmentInBytes cause crashes in CMBitMapClosure::do_bit
Summary: Making sure committed memory is cleared when re-committed, even if using large pages.
Reviewed-by: jwilhelm, tschatzl
author | sjohanss |
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date | Mon, 12 Jan 2015 15:24:29 +0100 |
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342 | 1 /* |
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2 * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved. |
342 | 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. |
342 | 22 * |
23 */ | |
24 | |
1972 | 25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1BLOCKOFFSETTABLE_HPP |
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_G1BLOCKOFFSETTABLE_HPP | |
27 | |
20337 | 28 #include "gc_implementation/g1/g1RegionToSpaceMapper.hpp" |
1972 | 29 #include "memory/memRegion.hpp" |
30 #include "runtime/virtualspace.hpp" | |
31 #include "utilities/globalDefinitions.hpp" | |
32 | |
342 | 33 // The CollectedHeap type requires subtypes to implement a method |
34 // "block_start". For some subtypes, notably generational | |
35 // systems using card-table-based write barriers, the efficiency of this | |
36 // operation may be important. Implementations of the "BlockOffsetArray" | |
37 // class may be useful in providing such efficient implementations. | |
38 // | |
39 // While generally mirroring the structure of the BOT for GenCollectedHeap, | |
40 // the following types are tailored more towards G1's uses; these should, | |
41 // however, be merged back into a common BOT to avoid code duplication | |
42 // and reduce maintenance overhead. | |
43 // | |
44 // G1BlockOffsetTable (abstract) | |
45 // -- G1BlockOffsetArray (uses G1BlockOffsetSharedArray) | |
46 // -- G1BlockOffsetArrayContigSpace | |
47 // | |
48 // A main impediment to the consolidation of this code might be the | |
49 // effect of making some of the block_start*() calls non-const as | |
50 // below. Whether that might adversely affect performance optimizations | |
51 // that compilers might normally perform in the case of non-G1 | |
52 // collectors needs to be carefully investigated prior to any such | |
53 // consolidation. | |
54 | |
55 // Forward declarations | |
56 class G1BlockOffsetSharedArray; | |
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57 class G1OffsetTableContigSpace; |
342 | 58 |
59 class G1BlockOffsetTable VALUE_OBJ_CLASS_SPEC { | |
60 friend class VMStructs; | |
61 protected: | |
62 // These members describe the region covered by the table. | |
63 | |
64 // The space this table is covering. | |
65 HeapWord* _bottom; // == reserved.start | |
66 HeapWord* _end; // End of currently allocated region. | |
67 | |
68 public: | |
69 // Initialize the table to cover the given space. | |
70 // The contents of the initial table are undefined. | |
71 G1BlockOffsetTable(HeapWord* bottom, HeapWord* end) : | |
72 _bottom(bottom), _end(end) | |
73 { | |
74 assert(_bottom <= _end, "arguments out of order"); | |
75 } | |
76 | |
77 // Note that the committed size of the covered space may have changed, | |
78 // so the table size might also wish to change. | |
79 virtual void resize(size_t new_word_size) = 0; | |
80 | |
81 virtual void set_bottom(HeapWord* new_bottom) { | |
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82 assert(new_bottom <= _end, |
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83 err_msg("new_bottom (" PTR_FORMAT ") > _end (" PTR_FORMAT ")", |
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84 p2i(new_bottom), p2i(_end))); |
342 | 85 _bottom = new_bottom; |
86 resize(pointer_delta(_end, _bottom)); | |
87 } | |
88 | |
89 // Requires "addr" to be contained by a block, and returns the address of | |
90 // the start of that block. (May have side effects, namely updating of | |
91 // shared array entries that "point" too far backwards. This can occur, | |
92 // for example, when LAB allocation is used in a space covered by the | |
93 // table.) | |
94 virtual HeapWord* block_start_unsafe(const void* addr) = 0; | |
95 // Same as above, but does not have any of the possible side effects | |
96 // discussed above. | |
97 virtual HeapWord* block_start_unsafe_const(const void* addr) const = 0; | |
98 | |
99 // Returns the address of the start of the block containing "addr", or | |
100 // else "null" if it is covered by no block. (May have side effects, | |
101 // namely updating of shared array entries that "point" too far | |
102 // backwards. This can occur, for example, when lab allocation is used | |
103 // in a space covered by the table.) | |
104 inline HeapWord* block_start(const void* addr); | |
105 // Same as above, but does not have any of the possible side effects | |
106 // discussed above. | |
107 inline HeapWord* block_start_const(const void* addr) const; | |
108 }; | |
109 | |
20337 | 110 class G1BlockOffsetSharedArrayMappingChangedListener : public G1MappingChangedListener { |
111 public: | |
20543 | 112 virtual void on_commit(uint start_idx, size_t num_regions, bool zero_filled) { |
20542 | 113 // Nothing to do. The BOT is hard-wired to be part of the HeapRegion, and we cannot |
114 // retrieve it here since this would cause firing of several asserts. The code | |
115 // executed after commit of a region already needs to do some re-initialization of | |
116 // the HeapRegion, so we combine that. | |
117 } | |
20337 | 118 }; |
119 | |
342 | 120 // This implementation of "G1BlockOffsetTable" divides the covered region |
121 // into "N"-word subregions (where "N" = 2^"LogN". An array with an entry | |
122 // for each such subregion indicates how far back one must go to find the | |
123 // start of the chunk that includes the first word of the subregion. | |
124 // | |
125 // Each BlockOffsetArray is owned by a Space. However, the actual array | |
126 // may be shared by several BlockOffsetArrays; this is useful | |
127 // when a single resizable area (such as a generation) is divided up into | |
128 // several spaces in which contiguous allocation takes place, | |
129 // such as, for example, in G1 or in the train generation.) | |
130 | |
131 // Here is the shared array type. | |
132 | |
6197 | 133 class G1BlockOffsetSharedArray: public CHeapObj<mtGC> { |
342 | 134 friend class G1BlockOffsetArray; |
135 friend class G1BlockOffsetArrayContigSpace; | |
136 friend class VMStructs; | |
137 | |
138 private: | |
20337 | 139 G1BlockOffsetSharedArrayMappingChangedListener _listener; |
342 | 140 // The reserved region covered by the shared array. |
141 MemRegion _reserved; | |
142 | |
143 // End of the current committed region. | |
144 HeapWord* _end; | |
145 | |
146 // Array for keeping offsets for retrieving object start fast given an | |
147 // address. | |
148 u_char* _offset_array; // byte array keeping backwards offsets | |
149 | |
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150 void check_offset(size_t offset, const char* msg) const { |
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151 assert(offset <= N_words, |
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152 err_msg("%s - " |
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153 "offset: " SIZE_FORMAT ", N_words: " UINT32_FORMAT, |
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154 msg, offset, N_words)); |
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155 } |
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156 |
342 | 157 // Bounds checking accessors: |
158 // For performance these have to devolve to array accesses in product builds. | |
20337 | 159 inline u_char offset_array(size_t index) const; |
342 | 160 |
20337 | 161 void set_offset_array_raw(size_t index, u_char offset) { |
342 | 162 _offset_array[index] = offset; |
163 } | |
164 | |
20337 | 165 inline void set_offset_array(size_t index, u_char offset); |
166 | |
167 inline void set_offset_array(size_t index, HeapWord* high, HeapWord* low); | |
342 | 168 |
20337 | 169 inline void set_offset_array(size_t left, size_t right, u_char offset); |
342 | 170 |
171 bool is_card_boundary(HeapWord* p) const; | |
172 | |
20337 | 173 public: |
174 | |
342 | 175 // Return the number of slots needed for an offset array |
176 // that covers mem_region_words words. | |
20337 | 177 static size_t compute_size(size_t mem_region_words) { |
178 size_t number_of_slots = (mem_region_words / N_words); | |
179 return ReservedSpace::allocation_align_size_up(number_of_slots); | |
342 | 180 } |
181 | |
182 enum SomePublicConstants { | |
183 LogN = 9, | |
184 LogN_words = LogN - LogHeapWordSize, | |
185 N_bytes = 1 << LogN, | |
186 N_words = 1 << LogN_words | |
187 }; | |
188 | |
189 // Initialize the table to cover from "base" to (at least) | |
190 // "base + init_word_size". In the future, the table may be expanded | |
191 // (see "resize" below) up to the size of "_reserved" (which must be at | |
192 // least "init_word_size".) The contents of the initial table are | |
193 // undefined; it is the responsibility of the constituent | |
194 // G1BlockOffsetTable(s) to initialize cards. | |
20337 | 195 G1BlockOffsetSharedArray(MemRegion heap, G1RegionToSpaceMapper* storage); |
342 | 196 |
197 // Return the appropriate index into "_offset_array" for "p". | |
198 inline size_t index_for(const void* p) const; | |
20337 | 199 inline size_t index_for_raw(const void* p) const; |
342 | 200 |
201 // Return the address indicating the start of the region corresponding to | |
202 // "index" in "_offset_array". | |
203 inline HeapWord* address_for_index(size_t index) const; | |
20337 | 204 // Variant of address_for_index that does not check the index for validity. |
205 inline HeapWord* address_for_index_raw(size_t index) const { | |
206 return _reserved.start() + (index << LogN_words); | |
207 } | |
342 | 208 }; |
209 | |
210 // And here is the G1BlockOffsetTable subtype that uses the array. | |
211 | |
212 class G1BlockOffsetArray: public G1BlockOffsetTable { | |
213 friend class G1BlockOffsetSharedArray; | |
214 friend class G1BlockOffsetArrayContigSpace; | |
215 friend class VMStructs; | |
216 private: | |
217 enum SomePrivateConstants { | |
218 N_words = G1BlockOffsetSharedArray::N_words, | |
219 LogN = G1BlockOffsetSharedArray::LogN | |
220 }; | |
221 | |
222 // This is the array, which can be shared by several BlockOffsetArray's | |
223 // servicing different | |
224 G1BlockOffsetSharedArray* _array; | |
225 | |
226 // The space that owns this subregion. | |
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227 G1OffsetTableContigSpace* _gsp; |
342 | 228 |
229 // The portion [_unallocated_block, _sp.end()) of the space that | |
230 // is a single block known not to contain any objects. | |
231 // NOTE: See BlockOffsetArrayUseUnallocatedBlock flag. | |
232 HeapWord* _unallocated_block; | |
233 | |
234 // Sets the entries | |
235 // corresponding to the cards starting at "start" and ending at "end" | |
236 // to point back to the card before "start": the interval [start, end) | |
237 // is right-open. | |
238 void set_remainder_to_point_to_start(HeapWord* start, HeapWord* end); | |
239 // Same as above, except that the args here are a card _index_ interval | |
240 // that is closed: [start_index, end_index] | |
241 void set_remainder_to_point_to_start_incl(size_t start, size_t end); | |
242 | |
243 protected: | |
244 | |
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245 G1OffsetTableContigSpace* gsp() const { return _gsp; } |
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246 |
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247 inline size_t block_size(const HeapWord* p) const; |
342 | 248 |
249 // Returns the address of a block whose start is at most "addr". | |
250 // If "has_max_index" is true, "assumes "max_index" is the last valid one | |
251 // in the array. | |
252 inline HeapWord* block_at_or_preceding(const void* addr, | |
253 bool has_max_index, | |
254 size_t max_index) const; | |
255 | |
256 // "q" is a block boundary that is <= "addr"; "n" is the address of the | |
257 // next block (or the end of the space.) Return the address of the | |
258 // beginning of the block that contains "addr". Does so without side | |
259 // effects (see, e.g., spec of block_start.) | |
260 inline HeapWord* | |
261 forward_to_block_containing_addr_const(HeapWord* q, HeapWord* n, | |
262 const void* addr) const; | |
263 | |
264 // "q" is a block boundary that is <= "addr"; return the address of the | |
265 // beginning of the block that contains "addr". May have side effects | |
266 // on "this", by updating imprecise entries. | |
267 inline HeapWord* forward_to_block_containing_addr(HeapWord* q, | |
268 const void* addr); | |
269 | |
270 // "q" is a block boundary that is <= "addr"; "n" is the address of the | |
271 // next block (or the end of the space.) Return the address of the | |
272 // beginning of the block that contains "addr". May have side effects | |
273 // on "this", by updating imprecise entries. | |
274 HeapWord* forward_to_block_containing_addr_slow(HeapWord* q, | |
275 HeapWord* n, | |
276 const void* addr); | |
277 | |
278 // Requires that "*threshold_" be the first array entry boundary at or | |
279 // above "blk_start", and that "*index_" be the corresponding array | |
280 // index. If the block starts at or crosses "*threshold_", records | |
281 // "blk_start" as the appropriate block start for the array index | |
282 // starting at "*threshold_", and for any other indices crossed by the | |
283 // block. Updates "*threshold_" and "*index_" to correspond to the first | |
284 // index after the block end. | |
285 void alloc_block_work2(HeapWord** threshold_, size_t* index_, | |
286 HeapWord* blk_start, HeapWord* blk_end); | |
287 | |
288 public: | |
289 // The space may not have it's bottom and top set yet, which is why the | |
20542 | 290 // region is passed as a parameter. The elements of the array are |
291 // initialized to zero. | |
292 G1BlockOffsetArray(G1BlockOffsetSharedArray* array, MemRegion mr); | |
342 | 293 |
294 // Note: this ought to be part of the constructor, but that would require | |
295 // "this" to be passed as a parameter to a member constructor for | |
296 // the containing concrete subtype of Space. | |
297 // This would be legal C++, but MS VC++ doesn't allow it. | |
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298 void set_space(G1OffsetTableContigSpace* sp); |
342 | 299 |
300 // Resets the covered region to one with the same _bottom as before but | |
301 // the "new_word_size". | |
302 void resize(size_t new_word_size); | |
303 | |
304 virtual HeapWord* block_start_unsafe(const void* addr); | |
305 virtual HeapWord* block_start_unsafe_const(const void* addr) const; | |
306 | |
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307 // Used by region verification. Checks that the contents of the |
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308 // BOT reflect that there's a single object that spans the address |
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309 // range [obj_start, obj_start + word_size); returns true if this is |
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310 // the case, returns false if it's not. |
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311 bool verify_for_object(HeapWord* obj_start, size_t word_size) const; |
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312 |
342 | 313 void check_all_cards(size_t left_card, size_t right_card) const; |
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314 |
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315 virtual void print_on(outputStream* out) PRODUCT_RETURN; |
342 | 316 }; |
317 | |
318 // A subtype of BlockOffsetArray that takes advantage of the fact | |
319 // that its underlying space is a ContiguousSpace, so that its "active" | |
320 // region can be more efficiently tracked (than for a non-contiguous space). | |
321 class G1BlockOffsetArrayContigSpace: public G1BlockOffsetArray { | |
322 friend class VMStructs; | |
323 | |
324 // allocation boundary at which offset array must be updated | |
325 HeapWord* _next_offset_threshold; | |
326 size_t _next_offset_index; // index corresponding to that boundary | |
327 | |
328 // Work function to be called when allocation start crosses the next | |
329 // threshold in the contig space. | |
330 void alloc_block_work1(HeapWord* blk_start, HeapWord* blk_end) { | |
331 alloc_block_work2(&_next_offset_threshold, &_next_offset_index, | |
332 blk_start, blk_end); | |
333 } | |
334 | |
20542 | 335 // Zero out the entry for _bottom (offset will be zero). Does not check for availability of the |
20337 | 336 // memory first. |
337 void zero_bottom_entry_raw(); | |
338 // Variant of initialize_threshold that does not check for availability of the | |
339 // memory first. | |
340 HeapWord* initialize_threshold_raw(); | |
342 | 341 public: |
342 G1BlockOffsetArrayContigSpace(G1BlockOffsetSharedArray* array, MemRegion mr); | |
343 | |
344 // Initialize the threshold to reflect the first boundary after the | |
345 // bottom of the covered region. | |
346 HeapWord* initialize_threshold(); | |
347 | |
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348 void reset_bot() { |
20337 | 349 zero_bottom_entry_raw(); |
350 initialize_threshold_raw(); | |
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351 } |
342 | 352 |
353 // Return the next threshold, the point at which the table should be | |
354 // updated. | |
355 HeapWord* threshold() const { return _next_offset_threshold; } | |
356 | |
357 // These must be guaranteed to work properly (i.e., do nothing) | |
358 // when "blk_start" ("blk" for second version) is "NULL". In this | |
359 // implementation, that's true because NULL is represented as 0, and thus | |
360 // never exceeds the "_next_offset_threshold". | |
361 void alloc_block(HeapWord* blk_start, HeapWord* blk_end) { | |
362 if (blk_end > _next_offset_threshold) | |
363 alloc_block_work1(blk_start, blk_end); | |
364 } | |
365 void alloc_block(HeapWord* blk, size_t size) { | |
366 alloc_block(blk, blk+size); | |
367 } | |
368 | |
369 HeapWord* block_start_unsafe(const void* addr); | |
370 HeapWord* block_start_unsafe_const(const void* addr) const; | |
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371 |
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372 void set_for_starts_humongous(HeapWord* new_top); |
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373 |
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374 virtual void print_on(outputStream* out) PRODUCT_RETURN; |
342 | 375 }; |
1972 | 376 |
377 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1BLOCKOFFSETTABLE_HPP |