Mercurial > hg > truffle
annotate src/share/vm/gc_implementation/parallelScavenge/psMarkSweepDecorator.cpp @ 269:850fdf70db2b
Merge
| author | jmasa |
|---|---|
| date | Mon, 28 Jul 2008 15:30:23 -0700 |
| parents | d1605aabd0a1 12eea04c8b06 |
| children | a4b729f5b611 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 196 | 2 * Copyright 2001-2008 Sun Microsystems, Inc. All Rights Reserved. |
| 0 | 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| 4 * | |
| 5 * This code is free software; you can redistribute it and/or modify it | |
| 6 * under the terms of the GNU General Public License version 2 only, as | |
| 7 * published by the Free Software Foundation. | |
| 8 * | |
| 9 * This code is distributed in the hope that it will be useful, but WITHOUT | |
| 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
| 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License | |
| 12 * version 2 for more details (a copy is included in the LICENSE file that | |
| 13 * accompanied this code). | |
| 14 * | |
| 15 * You should have received a copy of the GNU General Public License version | |
| 16 * 2 along with this work; if not, write to the Free Software Foundation, | |
| 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. | |
| 18 * | |
| 19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, | |
| 20 * CA 95054 USA or visit www.sun.com if you need additional information or | |
| 21 * have any questions. | |
| 22 * | |
| 23 */ | |
| 24 | |
| 25 # include "incls/_precompiled.incl" | |
| 26 # include "incls/_psMarkSweepDecorator.cpp.incl" | |
| 27 | |
| 28 PSMarkSweepDecorator* PSMarkSweepDecorator::_destination_decorator = NULL; | |
| 29 | |
| 30 | |
| 31 void PSMarkSweepDecorator::set_destination_decorator_tenured() { | |
| 32 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
| 33 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
| 34 | |
| 35 _destination_decorator = heap->old_gen()->object_mark_sweep(); | |
| 36 } | |
| 37 | |
| 38 void PSMarkSweepDecorator::set_destination_decorator_perm_gen() { | |
| 39 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
| 40 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
| 41 | |
| 42 _destination_decorator = heap->perm_gen()->object_mark_sweep(); | |
| 43 } | |
| 44 | |
| 45 void PSMarkSweepDecorator::advance_destination_decorator() { | |
| 46 ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); | |
| 47 assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); | |
| 48 | |
| 49 assert(_destination_decorator != NULL, "Sanity"); | |
| 50 guarantee(_destination_decorator != heap->perm_gen()->object_mark_sweep(), "Cannot advance perm gen decorator"); | |
| 51 | |
| 52 PSMarkSweepDecorator* first = heap->old_gen()->object_mark_sweep(); | |
| 53 PSMarkSweepDecorator* second = heap->young_gen()->eden_mark_sweep(); | |
| 54 PSMarkSweepDecorator* third = heap->young_gen()->from_mark_sweep(); | |
| 55 PSMarkSweepDecorator* fourth = heap->young_gen()->to_mark_sweep(); | |
| 56 | |
| 57 if ( _destination_decorator == first ) { | |
| 58 _destination_decorator = second; | |
| 59 } else if ( _destination_decorator == second ) { | |
| 60 _destination_decorator = third; | |
| 61 } else if ( _destination_decorator == third ) { | |
| 62 _destination_decorator = fourth; | |
| 63 } else { | |
| 64 fatal("PSMarkSweep attempting to advance past last compaction area"); | |
| 65 } | |
| 66 } | |
| 67 | |
| 68 PSMarkSweepDecorator* PSMarkSweepDecorator::destination_decorator() { | |
| 69 assert(_destination_decorator != NULL, "Sanity"); | |
| 70 | |
| 71 return _destination_decorator; | |
| 72 } | |
| 73 | |
| 74 // FIX ME FIX ME FIX ME FIX ME!!!!!!!!! | |
| 75 // The object forwarding code is duplicated. Factor this out!!!!! | |
| 76 // | |
| 77 // This method "precompacts" objects inside its space to dest. It places forwarding | |
| 78 // pointers into markOops for use by adjust_pointers. If "dest" should overflow, we | |
| 79 // finish by compacting into our own space. | |
| 80 | |
| 81 void PSMarkSweepDecorator::precompact() { | |
| 82 // Reset our own compact top. | |
| 83 set_compaction_top(space()->bottom()); | |
| 84 | |
| 85 /* We allow some amount of garbage towards the bottom of the space, so | |
| 86 * we don't start compacting before there is a significant gain to be made. | |
| 87 * Occasionally, we want to ensure a full compaction, which is determined | |
| 88 * by the MarkSweepAlwaysCompactCount parameter. This is a significant | |
| 89 * performance improvement! | |
| 90 */ | |
| 91 bool skip_dead = ((PSMarkSweep::total_invocations() % MarkSweepAlwaysCompactCount) != 0); | |
| 92 | |
| 93 ssize_t allowed_deadspace = 0; | |
| 94 if (skip_dead) { | |
| 95 int ratio = allowed_dead_ratio(); | |
| 96 allowed_deadspace = (space()->capacity_in_bytes() * ratio / 100) / HeapWordSize; | |
| 97 } | |
| 98 | |
| 99 // Fetch the current destination decorator | |
| 100 PSMarkSweepDecorator* dest = destination_decorator(); | |
| 101 ObjectStartArray* start_array = dest->start_array(); | |
| 102 | |
| 103 HeapWord* compact_top = dest->compaction_top(); | |
| 104 HeapWord* compact_end = dest->space()->end(); | |
| 105 | |
| 106 HeapWord* q = space()->bottom(); | |
| 107 HeapWord* t = space()->top(); | |
| 108 | |
| 109 HeapWord* end_of_live= q; /* One byte beyond the last byte of the last | |
| 110 live object. */ | |
| 111 HeapWord* first_dead = space()->end(); /* The first dead object. */ | |
| 112 LiveRange* liveRange = NULL; /* The current live range, recorded in the | |
| 113 first header of preceding free area. */ | |
| 114 _first_dead = first_dead; | |
| 115 | |
| 116 const intx interval = PrefetchScanIntervalInBytes; | |
| 117 | |
| 118 while (q < t) { | |
| 119 assert(oop(q)->mark()->is_marked() || oop(q)->mark()->is_unlocked() || | |
| 120 oop(q)->mark()->has_bias_pattern(), | |
| 121 "these are the only valid states during a mark sweep"); | |
| 122 if (oop(q)->is_gc_marked()) { | |
| 123 /* prefetch beyond q */ | |
| 124 Prefetch::write(q, interval); | |
| 125 size_t size = oop(q)->size(); | |
| 126 | |
| 127 size_t compaction_max_size = pointer_delta(compact_end, compact_top); | |
| 128 | |
| 129 // This should only happen if a space in the young gen overflows the | |
| 130 // old gen. If that should happen, we null out the start_array, because | |
| 131 // the young spaces are not covered by one. | |
| 132 while(size > compaction_max_size) { | |
| 133 // First record the last compact_top | |
| 134 dest->set_compaction_top(compact_top); | |
| 135 | |
| 136 // Advance to the next compaction decorator | |
| 137 advance_destination_decorator(); | |
| 138 dest = destination_decorator(); | |
| 139 | |
| 140 // Update compaction info | |
| 141 start_array = dest->start_array(); | |
| 142 compact_top = dest->compaction_top(); | |
| 143 compact_end = dest->space()->end(); | |
| 144 assert(compact_top == dest->space()->bottom(), "Advanced to space already in use"); | |
| 145 assert(compact_end > compact_top, "Must always be space remaining"); | |
| 146 compaction_max_size = | |
| 147 pointer_delta(compact_end, compact_top); | |
| 148 } | |
| 149 | |
| 150 // store the forwarding pointer into the mark word | |
| 151 if (q != compact_top) { | |
| 152 oop(q)->forward_to(oop(compact_top)); | |
| 153 assert(oop(q)->is_gc_marked(), "encoding the pointer should preserve the mark"); | |
| 154 } else { | |
| 155 // Don't clear the mark since it's confuses parallel old | |
| 156 // verification. | |
| 157 if (!UseParallelOldGC || !VerifyParallelOldWithMarkSweep) { | |
| 158 // if the object isn't moving we can just set the mark to the default | |
| 159 // mark and handle it specially later on. | |
| 160 oop(q)->init_mark(); | |
| 161 } | |
| 162 assert(oop(q)->forwardee() == NULL, "should be forwarded to NULL"); | |
| 163 } | |
| 164 | |
| 165 // Update object start array | |
| 166 if (!UseParallelOldGC || !VerifyParallelOldWithMarkSweep) { | |
| 167 if (start_array) | |
| 168 start_array->allocate_block(compact_top); | |
| 169 } | |
| 170 | |
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171 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::register_live_oop(oop(q), size)); |
| 0 | 172 compact_top += size; |
| 173 assert(compact_top <= dest->space()->end(), | |
| 174 "Exceeding space in destination"); | |
| 175 | |
| 176 q += size; | |
| 177 end_of_live = q; | |
| 178 } else { | |
| 179 /* run over all the contiguous dead objects */ | |
| 180 HeapWord* end = q; | |
| 181 do { | |
| 182 /* prefetch beyond end */ | |
| 183 Prefetch::write(end, interval); | |
| 184 end += oop(end)->size(); | |
| 185 } while (end < t && (!oop(end)->is_gc_marked())); | |
| 186 | |
| 187 /* see if we might want to pretend this object is alive so that | |
| 188 * we don't have to compact quite as often. | |
| 189 */ | |
| 190 if (allowed_deadspace > 0 && q == compact_top) { | |
| 191 size_t sz = pointer_delta(end, q); | |
| 192 if (insert_deadspace(allowed_deadspace, q, sz)) { | |
| 193 size_t compaction_max_size = pointer_delta(compact_end, compact_top); | |
| 194 | |
| 195 // This should only happen if a space in the young gen overflows the | |
| 196 // old gen. If that should happen, we null out the start_array, because | |
| 197 // the young spaces are not covered by one. | |
| 198 while (sz > compaction_max_size) { | |
| 199 // First record the last compact_top | |
| 200 dest->set_compaction_top(compact_top); | |
| 201 | |
| 202 // Advance to the next compaction decorator | |
| 203 advance_destination_decorator(); | |
| 204 dest = destination_decorator(); | |
| 205 | |
| 206 // Update compaction info | |
| 207 start_array = dest->start_array(); | |
| 208 compact_top = dest->compaction_top(); | |
| 209 compact_end = dest->space()->end(); | |
| 210 assert(compact_top == dest->space()->bottom(), "Advanced to space already in use"); | |
| 211 assert(compact_end > compact_top, "Must always be space remaining"); | |
| 212 compaction_max_size = | |
| 213 pointer_delta(compact_end, compact_top); | |
| 214 } | |
| 215 | |
| 216 // store the forwarding pointer into the mark word | |
| 217 if (q != compact_top) { | |
| 218 oop(q)->forward_to(oop(compact_top)); | |
| 219 assert(oop(q)->is_gc_marked(), "encoding the pointer should preserve the mark"); | |
| 220 } else { | |
| 221 // if the object isn't moving we can just set the mark to the default | |
| 222 // Don't clear the mark since it's confuses parallel old | |
| 223 // verification. | |
| 224 if (!UseParallelOldGC || !VerifyParallelOldWithMarkSweep) { | |
| 225 // mark and handle it specially later on. | |
| 226 oop(q)->init_mark(); | |
| 227 } | |
| 228 assert(oop(q)->forwardee() == NULL, "should be forwarded to NULL"); | |
| 229 } | |
| 230 | |
| 231 if (!UseParallelOldGC || !VerifyParallelOldWithMarkSweep) { | |
| 232 // Update object start array | |
| 233 if (start_array) | |
| 234 start_array->allocate_block(compact_top); | |
| 235 } | |
| 236 | |
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237 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::register_live_oop(oop(q), sz)); |
| 0 | 238 compact_top += sz; |
| 239 assert(compact_top <= dest->space()->end(), | |
| 240 "Exceeding space in destination"); | |
| 241 | |
| 242 q = end; | |
| 243 end_of_live = end; | |
| 244 continue; | |
| 245 } | |
| 246 } | |
| 247 | |
| 248 /* for the previous LiveRange, record the end of the live objects. */ | |
| 249 if (liveRange) { | |
| 250 liveRange->set_end(q); | |
| 251 } | |
| 252 | |
| 253 /* record the current LiveRange object. | |
| 254 * liveRange->start() is overlaid on the mark word. | |
| 255 */ | |
| 256 liveRange = (LiveRange*)q; | |
| 257 liveRange->set_start(end); | |
| 258 liveRange->set_end(end); | |
| 259 | |
| 260 /* see if this is the first dead region. */ | |
| 261 if (q < first_dead) { | |
| 262 first_dead = q; | |
| 263 } | |
| 264 | |
| 265 /* move on to the next object */ | |
| 266 q = end; | |
| 267 } | |
| 268 } | |
| 269 | |
| 270 assert(q == t, "just checking"); | |
| 271 if (liveRange != NULL) { | |
| 272 liveRange->set_end(q); | |
| 273 } | |
| 274 _end_of_live = end_of_live; | |
| 275 if (end_of_live < first_dead) { | |
| 276 first_dead = end_of_live; | |
| 277 } | |
| 278 _first_dead = first_dead; | |
| 279 | |
| 280 // Update compaction top | |
| 281 dest->set_compaction_top(compact_top); | |
| 282 } | |
| 283 | |
| 284 bool PSMarkSweepDecorator::insert_deadspace(ssize_t& allowed_deadspace_words, | |
| 285 HeapWord* q, size_t deadlength) { | |
| 286 allowed_deadspace_words -= deadlength; | |
| 287 if (allowed_deadspace_words >= 0) { | |
| 288 oop(q)->set_mark(markOopDesc::prototype()->set_marked()); | |
| 289 const size_t aligned_min_int_array_size = | |
| 290 align_object_size(typeArrayOopDesc::header_size(T_INT)); | |
| 291 if (deadlength >= aligned_min_int_array_size) { | |
| 292 oop(q)->set_klass(Universe::intArrayKlassObj()); | |
| 293 assert(((deadlength - aligned_min_int_array_size) * (HeapWordSize/sizeof(jint))) < (size_t)max_jint, | |
| 294 "deadspace too big for Arrayoop"); | |
| 295 typeArrayOop(q)->set_length((int)((deadlength - aligned_min_int_array_size) | |
| 296 * (HeapWordSize/sizeof(jint)))); | |
| 297 } else { | |
| 298 assert((int) deadlength == instanceOopDesc::header_size(), | |
| 299 "size for smallest fake dead object doesn't match"); | |
| 300 oop(q)->set_klass(SystemDictionary::object_klass()); | |
| 301 } | |
| 302 assert((int) deadlength == oop(q)->size(), | |
| 303 "make sure size for fake dead object match"); | |
| 304 // Recall that we required "q == compaction_top". | |
| 305 return true; | |
| 306 } else { | |
| 307 allowed_deadspace_words = 0; | |
| 308 return false; | |
| 309 } | |
| 310 } | |
| 311 | |
| 312 void PSMarkSweepDecorator::adjust_pointers() { | |
| 313 // adjust all the interior pointers to point at the new locations of objects | |
| 314 // Used by MarkSweep::mark_sweep_phase3() | |
| 315 | |
| 316 HeapWord* q = space()->bottom(); | |
| 317 HeapWord* t = _end_of_live; // Established by "prepare_for_compaction". | |
| 318 | |
| 319 assert(_first_dead <= _end_of_live, "Stands to reason, no?"); | |
| 320 | |
| 321 if (q < t && _first_dead > q && | |
| 322 !oop(q)->is_gc_marked()) { | |
| 323 // we have a chunk of the space which hasn't moved and we've | |
| 324 // reinitialized the mark word during the previous pass, so we can't | |
| 325 // use is_gc_marked for the traversal. | |
| 326 HeapWord* end = _first_dead; | |
| 327 | |
| 328 while (q < end) { | |
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329 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::track_interior_pointers(oop(q))); |
| 0 | 330 // point all the oops to the new location |
| 331 size_t size = oop(q)->adjust_pointers(); | |
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332 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::check_interior_pointers()); |
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333 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::validate_live_oop(oop(q), size)); |
| 0 | 334 q += size; |
| 335 } | |
| 336 | |
| 337 if (_first_dead == t) { | |
| 338 q = t; | |
| 339 } else { | |
| 340 // $$$ This is funky. Using this to read the previously written | |
| 341 // LiveRange. See also use below. | |
| 342 q = (HeapWord*)oop(_first_dead)->mark()->decode_pointer(); | |
| 343 } | |
| 344 } | |
| 345 const intx interval = PrefetchScanIntervalInBytes; | |
| 346 | |
| 347 debug_only(HeapWord* prev_q = NULL); | |
| 348 while (q < t) { | |
| 349 // prefetch beyond q | |
| 350 Prefetch::write(q, interval); | |
| 351 if (oop(q)->is_gc_marked()) { | |
| 352 // q is alive | |
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353 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::track_interior_pointers(oop(q))); |
| 0 | 354 // point all the oops to the new location |
| 355 size_t size = oop(q)->adjust_pointers(); | |
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356 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::check_interior_pointers()); |
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357 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::validate_live_oop(oop(q), size)); |
| 0 | 358 debug_only(prev_q = q); |
| 359 q += size; | |
| 360 } else { | |
| 361 // q is not a live object, so its mark should point at the next | |
| 362 // live object | |
| 363 debug_only(prev_q = q); | |
| 364 q = (HeapWord*) oop(q)->mark()->decode_pointer(); | |
| 365 assert(q > prev_q, "we should be moving forward through memory"); | |
| 366 } | |
| 367 } | |
| 368 | |
| 369 assert(q == t, "just checking"); | |
| 370 } | |
| 371 | |
| 372 void PSMarkSweepDecorator::compact(bool mangle_free_space ) { | |
| 373 // Copy all live objects to their new location | |
| 374 // Used by MarkSweep::mark_sweep_phase4() | |
| 375 | |
| 376 HeapWord* q = space()->bottom(); | |
| 377 HeapWord* const t = _end_of_live; | |
| 378 debug_only(HeapWord* prev_q = NULL); | |
| 379 | |
| 380 if (q < t && _first_dead > q && | |
| 381 !oop(q)->is_gc_marked()) { | |
| 382 #ifdef ASSERT | |
| 383 // we have a chunk of the space which hasn't moved and we've reinitialized the | |
| 384 // mark word during the previous pass, so we can't use is_gc_marked for the | |
| 385 // traversal. | |
| 386 HeapWord* const end = _first_dead; | |
| 387 | |
| 388 while (q < end) { | |
| 389 size_t size = oop(q)->size(); | |
| 390 assert(!oop(q)->is_gc_marked(), "should be unmarked (special dense prefix handling)"); | |
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391 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::live_oop_moved_to(q, size, q)); |
| 0 | 392 debug_only(prev_q = q); |
| 393 q += size; | |
| 394 } | |
| 395 #endif | |
| 396 | |
| 397 if (_first_dead == t) { | |
| 398 q = t; | |
| 399 } else { | |
| 400 // $$$ Funky | |
| 401 q = (HeapWord*) oop(_first_dead)->mark()->decode_pointer(); | |
| 402 } | |
| 403 } | |
| 404 | |
| 405 const intx scan_interval = PrefetchScanIntervalInBytes; | |
| 406 const intx copy_interval = PrefetchCopyIntervalInBytes; | |
| 407 | |
| 408 while (q < t) { | |
| 409 if (!oop(q)->is_gc_marked()) { | |
| 410 // mark is pointer to next marked oop | |
| 411 debug_only(prev_q = q); | |
| 412 q = (HeapWord*) oop(q)->mark()->decode_pointer(); | |
| 413 assert(q > prev_q, "we should be moving forward through memory"); | |
| 414 } else { | |
| 415 // prefetch beyond q | |
| 416 Prefetch::read(q, scan_interval); | |
| 417 | |
| 418 // size and destination | |
| 419 size_t size = oop(q)->size(); | |
| 420 HeapWord* compaction_top = (HeapWord*)oop(q)->forwardee(); | |
| 421 | |
| 422 // prefetch beyond compaction_top | |
| 423 Prefetch::write(compaction_top, copy_interval); | |
| 424 | |
| 425 // copy object and reinit its mark | |
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426 VALIDATE_MARK_SWEEP_ONLY(MarkSweep::live_oop_moved_to(q, size, compaction_top)); |
| 0 | 427 assert(q != compaction_top, "everything in this pass should be moving"); |
| 428 Copy::aligned_conjoint_words(q, compaction_top, size); | |
| 429 oop(compaction_top)->init_mark(); | |
| 430 assert(oop(compaction_top)->klass() != NULL, "should have a class"); | |
| 431 | |
| 432 debug_only(prev_q = q); | |
| 433 q += size; | |
| 434 } | |
| 435 } | |
| 436 | |
| 437 assert(compaction_top() >= space()->bottom() && compaction_top() <= space()->end(), | |
| 438 "should point inside space"); | |
| 439 space()->set_top(compaction_top()); | |
| 440 | |
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441 if (mangle_free_space) { |
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442 space()->mangle_unused_area(); |
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443 } |
| 0 | 444 } |