Mercurial > hg > graal-compiler
annotate src/share/vm/memory/cardTableModRefBS.hpp @ 1692:d2ede61b7a12
6976186: integrate Shark HotSpot changes
Summary: Shark is a JIT compiler for Zero that uses the LLVM compiler infrastructure.
Reviewed-by: kvn, twisti
Contributed-by: Gary Benson <gbenson@redhat.com>
| author | twisti |
|---|---|
| date | Wed, 11 Aug 2010 05:51:21 -0700 |
| parents | c18cbe5936b8 |
| children | f95d63e2154a |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 1692 | 2 * Copyright (c) 2000, 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 | |
| 25 // This kind of "BarrierSet" allows a "CollectedHeap" to detect and | |
| 26 // enumerate ref fields that have been modified (since the last | |
| 27 // enumeration.) | |
| 28 | |
| 29 // As it currently stands, this barrier is *imprecise*: when a ref field in | |
| 30 // an object "o" is modified, the card table entry for the card containing | |
| 31 // the head of "o" is dirtied, not necessarily the card containing the | |
| 32 // modified field itself. For object arrays, however, the barrier *is* | |
| 33 // precise; only the card containing the modified element is dirtied. | |
| 34 // Any MemRegionClosures used to scan dirty cards should take these | |
| 35 // considerations into account. | |
| 36 | |
| 37 class Generation; | |
| 38 class OopsInGenClosure; | |
| 39 class DirtyCardToOopClosure; | |
| 40 | |
| 41 class CardTableModRefBS: public ModRefBarrierSet { | |
| 42 // Some classes get to look at some private stuff. | |
| 43 friend class BytecodeInterpreter; | |
| 44 friend class VMStructs; | |
| 45 friend class CardTableRS; | |
| 46 friend class CheckForUnmarkedOops; // Needs access to raw card bytes. | |
| 1692 | 47 friend class SharkBuilder; |
| 0 | 48 #ifndef PRODUCT |
| 49 // For debugging. | |
| 50 friend class GuaranteeNotModClosure; | |
| 51 #endif | |
| 52 protected: | |
| 53 | |
| 54 enum CardValues { | |
| 55 clean_card = -1, | |
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56 // The mask contains zeros in places for all other values. |
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57 clean_card_mask = clean_card - 31, |
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58 |
| 0 | 59 dirty_card = 0, |
| 60 precleaned_card = 1, | |
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61 claimed_card = 2, |
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62 deferred_card = 4, |
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63 last_card = 8, |
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64 CT_MR_BS_last_reserved = 16 |
| 0 | 65 }; |
| 66 | |
| 67 // dirty and precleaned are equivalent wrt younger_refs_iter. | |
| 68 static bool card_is_dirty_wrt_gen_iter(jbyte cv) { | |
| 69 return cv == dirty_card || cv == precleaned_card; | |
| 70 } | |
| 71 | |
| 72 // Returns "true" iff the value "cv" will cause the card containing it | |
| 73 // to be scanned in the current traversal. May be overridden by | |
| 74 // subtypes. | |
| 75 virtual bool card_will_be_scanned(jbyte cv) { | |
| 76 return CardTableModRefBS::card_is_dirty_wrt_gen_iter(cv); | |
| 77 } | |
| 78 | |
| 79 // Returns "true" iff the value "cv" may have represented a dirty card at | |
| 80 // some point. | |
| 81 virtual bool card_may_have_been_dirty(jbyte cv) { | |
| 82 return card_is_dirty_wrt_gen_iter(cv); | |
| 83 } | |
| 84 | |
| 85 // The declaration order of these const fields is important; see the | |
| 86 // constructor before changing. | |
| 87 const MemRegion _whole_heap; // the region covered by the card table | |
| 88 const size_t _guard_index; // index of very last element in the card | |
| 89 // table; it is set to a guard value | |
| 90 // (last_card) and should never be modified | |
| 91 const size_t _last_valid_index; // index of the last valid element | |
| 92 const size_t _page_size; // page size used when mapping _byte_map | |
| 93 const size_t _byte_map_size; // in bytes | |
| 94 jbyte* _byte_map; // the card marking array | |
| 95 | |
| 96 int _cur_covered_regions; | |
| 97 // The covered regions should be in address order. | |
| 98 MemRegion* _covered; | |
| 99 // The committed regions correspond one-to-one to the covered regions. | |
| 100 // They represent the card-table memory that has been committed to service | |
| 101 // the corresponding covered region. It may be that committed region for | |
| 102 // one covered region corresponds to a larger region because of page-size | |
| 103 // roundings. Thus, a committed region for one covered region may | |
| 104 // actually extend onto the card-table space for the next covered region. | |
| 105 MemRegion* _committed; | |
| 106 | |
| 107 // The last card is a guard card, and we commit the page for it so | |
| 108 // we can use the card for verification purposes. We make sure we never | |
| 109 // uncommit the MemRegion for that page. | |
| 110 MemRegion _guard_region; | |
| 111 | |
| 112 protected: | |
| 113 // Initialization utilities; covered_words is the size of the covered region | |
| 114 // in, um, words. | |
| 115 inline size_t cards_required(size_t covered_words); | |
| 116 inline size_t compute_byte_map_size(); | |
| 117 | |
| 118 // Finds and return the index of the region, if any, to which the given | |
| 119 // region would be contiguous. If none exists, assign a new region and | |
| 120 // returns its index. Requires that no more than the maximum number of | |
| 121 // covered regions defined in the constructor are ever in use. | |
| 122 int find_covering_region_by_base(HeapWord* base); | |
| 123 | |
| 124 // Same as above, but finds the region containing the given address | |
| 125 // instead of starting at a given base address. | |
| 126 int find_covering_region_containing(HeapWord* addr); | |
| 127 | |
| 128 // Resize one of the regions covered by the remembered set. | |
| 129 void resize_covered_region(MemRegion new_region); | |
| 130 | |
| 131 // Returns the leftmost end of a committed region corresponding to a | |
| 132 // covered region before covered region "ind", or else "NULL" if "ind" is | |
| 133 // the first covered region. | |
| 134 HeapWord* largest_prev_committed_end(int ind) const; | |
| 135 | |
| 136 // Returns the part of the region mr that doesn't intersect with | |
| 137 // any committed region other than self. Used to prevent uncommitting | |
| 138 // regions that are also committed by other regions. Also protects | |
| 139 // against uncommitting the guard region. | |
| 140 MemRegion committed_unique_to_self(int self, MemRegion mr) const; | |
| 141 | |
| 142 // Mapping from address to card marking array entry | |
| 143 jbyte* byte_for(const void* p) const { | |
| 144 assert(_whole_heap.contains(p), | |
| 145 "out of bounds access to card marking array"); | |
| 146 jbyte* result = &byte_map_base[uintptr_t(p) >> card_shift]; | |
| 147 assert(result >= _byte_map && result < _byte_map + _byte_map_size, | |
| 148 "out of bounds accessor for card marking array"); | |
| 149 return result; | |
| 150 } | |
| 151 | |
| 152 // The card table byte one after the card marking array | |
| 153 // entry for argument address. Typically used for higher bounds | |
| 154 // for loops iterating through the card table. | |
| 155 jbyte* byte_after(const void* p) const { | |
| 156 return byte_for(p) + 1; | |
| 157 } | |
| 158 | |
| 159 // Iterate over the portion of the card-table which covers the given | |
| 160 // region mr in the given space and apply cl to any dirty sub-regions | |
| 161 // of mr. cl and dcto_cl must either be the same closure or cl must | |
| 162 // wrap dcto_cl. Both are required - neither may be NULL. Also, dcto_cl | |
| 163 // may be modified. Note that this function will operate in a parallel | |
| 164 // mode if worker threads are available. | |
| 165 void non_clean_card_iterate(Space* sp, MemRegion mr, | |
| 166 DirtyCardToOopClosure* dcto_cl, | |
| 167 MemRegionClosure* cl, | |
| 168 bool clear); | |
| 169 | |
| 170 // Utility function used to implement the other versions below. | |
| 171 void non_clean_card_iterate_work(MemRegion mr, MemRegionClosure* cl, | |
| 172 bool clear); | |
| 173 | |
| 174 void par_non_clean_card_iterate_work(Space* sp, MemRegion mr, | |
| 175 DirtyCardToOopClosure* dcto_cl, | |
| 176 MemRegionClosure* cl, | |
| 177 bool clear, | |
| 178 int n_threads); | |
| 179 | |
| 180 // Dirty the bytes corresponding to "mr" (not all of which must be | |
| 181 // covered.) | |
| 182 void dirty_MemRegion(MemRegion mr); | |
| 183 | |
| 184 // Clear (to clean_card) the bytes entirely contained within "mr" (not | |
| 185 // all of which must be covered.) | |
| 186 void clear_MemRegion(MemRegion mr); | |
| 187 | |
| 188 // *** Support for parallel card scanning. | |
| 189 | |
| 190 enum SomeConstantsForParallelism { | |
| 191 StridesPerThread = 2, | |
| 192 CardsPerStrideChunk = 256 | |
| 193 }; | |
| 194 | |
| 195 // This is an array, one element per covered region of the card table. | |
| 196 // Each entry is itself an array, with one element per chunk in the | |
| 197 // covered region. Each entry of these arrays is the lowest non-clean | |
| 198 // card of the corresponding chunk containing part of an object from the | |
| 199 // previous chunk, or else NULL. | |
| 200 typedef jbyte* CardPtr; | |
| 201 typedef CardPtr* CardArr; | |
| 202 CardArr* _lowest_non_clean; | |
| 203 size_t* _lowest_non_clean_chunk_size; | |
| 204 uintptr_t* _lowest_non_clean_base_chunk_index; | |
| 205 int* _last_LNC_resizing_collection; | |
| 206 | |
| 207 // Initializes "lowest_non_clean" to point to the array for the region | |
| 208 // covering "sp", and "lowest_non_clean_base_chunk_index" to the chunk | |
| 209 // index of the corresponding to the first element of that array. | |
| 210 // Ensures that these arrays are of sufficient size, allocating if necessary. | |
| 211 // May be called by several threads concurrently. | |
| 212 void get_LNC_array_for_space(Space* sp, | |
| 213 jbyte**& lowest_non_clean, | |
| 214 uintptr_t& lowest_non_clean_base_chunk_index, | |
| 215 size_t& lowest_non_clean_chunk_size); | |
| 216 | |
| 217 // Returns the number of chunks necessary to cover "mr". | |
| 218 size_t chunks_to_cover(MemRegion mr) { | |
| 219 return (size_t)(addr_to_chunk_index(mr.last()) - | |
| 220 addr_to_chunk_index(mr.start()) + 1); | |
| 221 } | |
| 222 | |
| 223 // Returns the index of the chunk in a stride which | |
| 224 // covers the given address. | |
| 225 uintptr_t addr_to_chunk_index(const void* addr) { | |
| 226 uintptr_t card = (uintptr_t) byte_for(addr); | |
| 227 return card / CardsPerStrideChunk; | |
| 228 } | |
| 229 | |
| 230 // Apply cl, which must either itself apply dcto_cl or be dcto_cl, | |
| 231 // to the cards in the stride (of n_strides) within the given space. | |
| 232 void process_stride(Space* sp, | |
| 233 MemRegion used, | |
| 234 jint stride, int n_strides, | |
| 235 DirtyCardToOopClosure* dcto_cl, | |
| 236 MemRegionClosure* cl, | |
| 237 bool clear, | |
| 238 jbyte** lowest_non_clean, | |
| 239 uintptr_t lowest_non_clean_base_chunk_index, | |
| 240 size_t lowest_non_clean_chunk_size); | |
| 241 | |
| 242 // Makes sure that chunk boundaries are handled appropriately, by | |
| 243 // adjusting the min_done of dcto_cl, and by using a special card-table | |
| 244 // value to indicate how min_done should be set. | |
| 245 void process_chunk_boundaries(Space* sp, | |
| 246 DirtyCardToOopClosure* dcto_cl, | |
| 247 MemRegion chunk_mr, | |
| 248 MemRegion used, | |
| 249 jbyte** lowest_non_clean, | |
| 250 uintptr_t lowest_non_clean_base_chunk_index, | |
| 251 size_t lowest_non_clean_chunk_size); | |
| 252 | |
| 253 public: | |
| 254 // Constants | |
| 255 enum SomePublicConstants { | |
| 256 card_shift = 9, | |
| 257 card_size = 1 << card_shift, | |
| 258 card_size_in_words = card_size / sizeof(HeapWord) | |
| 259 }; | |
| 260 | |
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261 static int clean_card_val() { return clean_card; } |
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262 static int clean_card_mask_val() { return clean_card_mask; } |
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263 static int dirty_card_val() { return dirty_card; } |
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264 static int claimed_card_val() { return claimed_card; } |
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265 static int precleaned_card_val() { return precleaned_card; } |
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266 static int deferred_card_val() { return deferred_card; } |
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267 |
| 0 | 268 // For RTTI simulation. |
| 269 bool is_a(BarrierSet::Name bsn) { | |
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270 return bsn == BarrierSet::CardTableModRef || ModRefBarrierSet::is_a(bsn); |
| 0 | 271 } |
| 272 | |
| 273 CardTableModRefBS(MemRegion whole_heap, int max_covered_regions); | |
| 274 | |
| 275 // *** Barrier set functions. | |
| 276 | |
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277 bool has_write_ref_pre_barrier() { return false; } |
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278 |
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279 inline bool write_ref_needs_barrier(void* field, oop new_val) { |
| 0 | 280 // Note that this assumes the perm gen is the highest generation |
| 281 // in the address space | |
| 282 return new_val != NULL && !new_val->is_perm(); | |
| 283 } | |
| 284 | |
| 285 // Record a reference update. Note that these versions are precise! | |
| 286 // The scanning code has to handle the fact that the write barrier may be | |
| 287 // either precise or imprecise. We make non-virtual inline variants of | |
| 288 // these functions here for performance. | |
| 289 protected: | |
| 290 void write_ref_field_work(oop obj, size_t offset, oop newVal); | |
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291 virtual void write_ref_field_work(void* field, oop newVal); |
| 0 | 292 public: |
| 293 | |
| 294 bool has_write_ref_array_opt() { return true; } | |
| 295 bool has_write_region_opt() { return true; } | |
| 296 | |
| 297 inline void inline_write_region(MemRegion mr) { | |
| 298 dirty_MemRegion(mr); | |
| 299 } | |
| 300 protected: | |
| 301 void write_region_work(MemRegion mr) { | |
| 302 inline_write_region(mr); | |
| 303 } | |
| 304 public: | |
| 305 | |
| 306 inline void inline_write_ref_array(MemRegion mr) { | |
| 307 dirty_MemRegion(mr); | |
| 308 } | |
| 309 protected: | |
| 310 void write_ref_array_work(MemRegion mr) { | |
| 311 inline_write_ref_array(mr); | |
| 312 } | |
| 313 public: | |
| 314 | |
| 315 bool is_aligned(HeapWord* addr) { | |
| 316 return is_card_aligned(addr); | |
| 317 } | |
| 318 | |
| 319 // *** Card-table-barrier-specific things. | |
| 320 | |
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321 template <class T> inline void inline_write_ref_field_pre(T* field, oop newVal) {} |
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322 |
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323 template <class T> inline void inline_write_ref_field(T* field, oop newVal) { |
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324 jbyte* byte = byte_for((void*)field); |
| 0 | 325 *byte = dirty_card; |
| 326 } | |
| 327 | |
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328 // These are used by G1, when it uses the card table as a temporary data |
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329 // structure for card claiming. |
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330 bool is_card_dirty(size_t card_index) { |
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331 return _byte_map[card_index] == dirty_card_val(); |
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332 } |
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333 |
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334 void mark_card_dirty(size_t card_index) { |
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335 _byte_map[card_index] = dirty_card_val(); |
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336 } |
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337 |
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338 bool is_card_claimed(size_t card_index) { |
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339 jbyte val = _byte_map[card_index]; |
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340 return (val & (clean_card_mask_val() | claimed_card_val())) == claimed_card_val(); |
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341 } |
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342 |
| 1261 | 343 void set_card_claimed(size_t card_index) { |
| 344 jbyte val = _byte_map[card_index]; | |
| 345 if (val == clean_card_val()) { | |
| 346 val = (jbyte)claimed_card_val(); | |
| 347 } else { | |
| 348 val |= (jbyte)claimed_card_val(); | |
| 349 } | |
| 350 _byte_map[card_index] = val; | |
| 351 } | |
| 352 | |
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353 bool claim_card(size_t card_index); |
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354 |
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355 bool is_card_clean(size_t card_index) { |
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356 return _byte_map[card_index] == clean_card_val(); |
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357 } |
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358 |
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359 bool is_card_deferred(size_t card_index) { |
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360 jbyte val = _byte_map[card_index]; |
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361 return (val & (clean_card_mask_val() | deferred_card_val())) == deferred_card_val(); |
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362 } |
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363 |
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364 bool mark_card_deferred(size_t card_index); |
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365 |
| 0 | 366 // Card marking array base (adjusted for heap low boundary) |
| 367 // This would be the 0th element of _byte_map, if the heap started at 0x0. | |
| 368 // But since the heap starts at some higher address, this points to somewhere | |
| 369 // before the beginning of the actual _byte_map. | |
| 370 jbyte* byte_map_base; | |
| 371 | |
| 372 // Return true if "p" is at the start of a card. | |
| 373 bool is_card_aligned(HeapWord* p) { | |
| 374 jbyte* pcard = byte_for(p); | |
| 375 return (addr_for(pcard) == p); | |
| 376 } | |
| 377 | |
| 378 // The kinds of precision a CardTableModRefBS may offer. | |
| 379 enum PrecisionStyle { | |
| 380 Precise, | |
| 381 ObjHeadPreciseArray | |
| 382 }; | |
| 383 | |
| 384 // Tells what style of precision this card table offers. | |
| 385 PrecisionStyle precision() { | |
| 386 return ObjHeadPreciseArray; // Only one supported for now. | |
| 387 } | |
| 388 | |
| 389 // ModRefBS functions. | |
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390 virtual void invalidate(MemRegion mr, bool whole_heap = false); |
| 0 | 391 void clear(MemRegion mr); |
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392 void dirty(MemRegion mr); |
| 0 | 393 void mod_oop_in_space_iterate(Space* sp, OopClosure* cl, |
| 394 bool clear = false, | |
| 395 bool before_save_marks = false); | |
| 396 | |
| 397 // *** Card-table-RemSet-specific things. | |
| 398 | |
| 399 // Invoke "cl.do_MemRegion" on a set of MemRegions that collectively | |
| 400 // includes all the modified cards (expressing each card as a | |
| 401 // MemRegion). Thus, several modified cards may be lumped into one | |
| 402 // region. The regions are non-overlapping, and are visited in | |
| 403 // *decreasing* address order. (This order aids with imprecise card | |
| 404 // marking, where a dirty card may cause scanning, and summarization | |
| 405 // marking, of objects that extend onto subsequent cards.) | |
| 406 // If "clear" is true, the card is (conceptually) marked unmodified before | |
| 407 // applying the closure. | |
| 408 void mod_card_iterate(MemRegionClosure* cl, bool clear = false) { | |
| 409 non_clean_card_iterate_work(_whole_heap, cl, clear); | |
| 410 } | |
| 411 | |
| 412 // Like the "mod_cards_iterate" above, except only invokes the closure | |
| 413 // for cards within the MemRegion "mr" (which is required to be | |
| 414 // card-aligned and sized.) | |
| 415 void mod_card_iterate(MemRegion mr, MemRegionClosure* cl, | |
| 416 bool clear = false) { | |
| 417 non_clean_card_iterate_work(mr, cl, clear); | |
| 418 } | |
| 419 | |
| 420 static uintx ct_max_alignment_constraint(); | |
| 421 | |
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422 // Apply closure "cl" to the dirty cards containing some part of |
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423 // MemRegion "mr". |
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424 void dirty_card_iterate(MemRegion mr, MemRegionClosure* cl); |
| 0 | 425 |
| 426 // Return the MemRegion corresponding to the first maximal run | |
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427 // of dirty cards lying completely within MemRegion mr. |
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428 // If reset is "true", then sets those card table entries to the given |
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429 // value. |
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430 MemRegion dirty_card_range_after_reset(MemRegion mr, bool reset, |
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431 int reset_val); |
| 0 | 432 |
| 433 // Set all the dirty cards in the given region to precleaned state. | |
| 434 void preclean_dirty_cards(MemRegion mr); | |
| 435 | |
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436 // Provide read-only access to the card table array. |
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437 const jbyte* byte_for_const(const void* p) const { |
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438 return byte_for(p); |
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439 } |
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440 const jbyte* byte_after_const(const void* p) const { |
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441 return byte_after(p); |
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442 } |
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443 |
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444 // Mapping from card marking array entry to address of first word |
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445 HeapWord* addr_for(const jbyte* p) const { |
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446 assert(p >= _byte_map && p < _byte_map + _byte_map_size, |
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447 "out of bounds access to card marking array"); |
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448 size_t delta = pointer_delta(p, byte_map_base, sizeof(jbyte)); |
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449 HeapWord* result = (HeapWord*) (delta << card_shift); |
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450 assert(_whole_heap.contains(result), |
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451 "out of bounds accessor from card marking array"); |
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452 return result; |
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453 } |
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454 |
| 0 | 455 // Mapping from address to card marking array index. |
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456 size_t index_for(void* p) { |
| 0 | 457 assert(_whole_heap.contains(p), |
| 458 "out of bounds access to card marking array"); | |
| 459 return byte_for(p) - _byte_map; | |
| 460 } | |
| 461 | |
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462 const jbyte* byte_for_index(const size_t card_index) const { |
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463 return _byte_map + card_index; |
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464 } |
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465 |
| 0 | 466 void verify(); |
| 467 void verify_guard(); | |
| 468 | |
| 469 void verify_clean_region(MemRegion mr) PRODUCT_RETURN; | |
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470 void verify_dirty_region(MemRegion mr) PRODUCT_RETURN; |
| 0 | 471 |
| 472 static size_t par_chunk_heapword_alignment() { | |
| 473 return CardsPerStrideChunk * card_size_in_words; | |
| 474 } | |
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475 |
| 0 | 476 }; |
| 477 | |
| 478 class CardTableRS; | |
| 479 | |
| 480 // A specialization for the CardTableRS gen rem set. | |
| 481 class CardTableModRefBSForCTRS: public CardTableModRefBS { | |
| 482 CardTableRS* _rs; | |
| 483 protected: | |
| 484 bool card_will_be_scanned(jbyte cv); | |
| 485 bool card_may_have_been_dirty(jbyte cv); | |
| 486 public: | |
| 487 CardTableModRefBSForCTRS(MemRegion whole_heap, | |
| 488 int max_covered_regions) : | |
| 489 CardTableModRefBS(whole_heap, max_covered_regions) {} | |
| 490 | |
| 491 void set_CTRS(CardTableRS* rs) { _rs = rs; } | |
| 492 }; |