Mercurial > hg > truffle
annotate src/share/vm/memory/genCollectedHeap.cpp @ 269:850fdf70db2b
Merge
| author | jmasa |
|---|---|
| date | Mon, 28 Jul 2008 15:30:23 -0700 |
| parents | 1fdb98a17101 12eea04c8b06 |
| children | c96030fff130 |
| rev | line source |
|---|---|
| 0 | 1 /* |
| 196 | 2 * Copyright 2000-2008 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/_genCollectedHeap.cpp.incl" | |
| 27 | |
| 28 GenCollectedHeap* GenCollectedHeap::_gch; | |
| 29 NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;) | |
| 30 | |
| 31 // The set of potentially parallel tasks in strong root scanning. | |
| 32 enum GCH_process_strong_roots_tasks { | |
| 33 // We probably want to parallelize both of these internally, but for now... | |
| 34 GCH_PS_younger_gens, | |
| 35 // Leave this one last. | |
| 36 GCH_PS_NumElements | |
| 37 }; | |
| 38 | |
| 39 GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) : | |
| 40 SharedHeap(policy), | |
| 41 _gen_policy(policy), | |
| 42 _gen_process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)), | |
| 43 _full_collections_completed(0) | |
| 44 { | |
| 45 if (_gen_process_strong_tasks == NULL || | |
| 46 !_gen_process_strong_tasks->valid()) { | |
| 47 vm_exit_during_initialization("Failed necessary allocation."); | |
| 48 } | |
| 49 assert(policy != NULL, "Sanity check"); | |
| 50 _preloading_shared_classes = false; | |
| 51 } | |
| 52 | |
| 53 jint GenCollectedHeap::initialize() { | |
| 54 int i; | |
| 55 _n_gens = gen_policy()->number_of_generations(); | |
| 56 | |
| 57 // While there are no constraints in the GC code that HeapWordSize | |
| 58 // be any particular value, there are multiple other areas in the | |
| 59 // system which believe this to be true (e.g. oop->object_size in some | |
| 60 // cases incorrectly returns the size in wordSize units rather than | |
| 61 // HeapWordSize). | |
| 62 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize"); | |
| 63 | |
| 64 // The heap must be at least as aligned as generations. | |
| 65 size_t alignment = Generation::GenGrain; | |
| 66 | |
| 67 _gen_specs = gen_policy()->generations(); | |
| 68 PermanentGenerationSpec *perm_gen_spec = | |
| 69 collector_policy()->permanent_generation(); | |
| 70 | |
| 71 // Make sure the sizes are all aligned. | |
| 72 for (i = 0; i < _n_gens; i++) { | |
| 73 _gen_specs[i]->align(alignment); | |
| 74 } | |
| 75 perm_gen_spec->align(alignment); | |
| 76 | |
| 77 // If we are dumping the heap, then allocate a wasted block of address | |
| 78 // space in order to push the heap to a lower address. This extra | |
| 79 // address range allows for other (or larger) libraries to be loaded | |
| 80 // without them occupying the space required for the shared spaces. | |
| 81 | |
| 82 if (DumpSharedSpaces) { | |
| 83 uintx reserved = 0; | |
| 84 uintx block_size = 64*1024*1024; | |
| 85 while (reserved < SharedDummyBlockSize) { | |
| 86 char* dummy = os::reserve_memory(block_size); | |
| 87 reserved += block_size; | |
| 88 } | |
| 89 } | |
| 90 | |
| 91 // Allocate space for the heap. | |
| 92 | |
| 93 char* heap_address; | |
| 94 size_t total_reserved = 0; | |
| 95 int n_covered_regions = 0; | |
| 96 ReservedSpace heap_rs(0); | |
| 97 | |
| 98 heap_address = allocate(alignment, perm_gen_spec, &total_reserved, | |
| 99 &n_covered_regions, &heap_rs); | |
| 100 | |
| 101 if (UseSharedSpaces) { | |
| 102 if (!heap_rs.is_reserved() || heap_address != heap_rs.base()) { | |
| 103 if (heap_rs.is_reserved()) { | |
| 104 heap_rs.release(); | |
| 105 } | |
| 106 FileMapInfo* mapinfo = FileMapInfo::current_info(); | |
| 107 mapinfo->fail_continue("Unable to reserve shared region."); | |
| 108 allocate(alignment, perm_gen_spec, &total_reserved, &n_covered_regions, | |
| 109 &heap_rs); | |
| 110 } | |
| 111 } | |
| 112 | |
| 113 if (!heap_rs.is_reserved()) { | |
| 114 vm_shutdown_during_initialization( | |
| 115 "Could not reserve enough space for object heap"); | |
| 116 return JNI_ENOMEM; | |
| 117 } | |
| 118 | |
| 119 _reserved = MemRegion((HeapWord*)heap_rs.base(), | |
| 120 (HeapWord*)(heap_rs.base() + heap_rs.size())); | |
| 121 | |
| 122 // It is important to do this in a way such that concurrent readers can't | |
| 123 // temporarily think somethings in the heap. (Seen this happen in asserts.) | |
| 124 _reserved.set_word_size(0); | |
| 125 _reserved.set_start((HeapWord*)heap_rs.base()); | |
| 126 size_t actual_heap_size = heap_rs.size() - perm_gen_spec->misc_data_size() | |
| 127 - perm_gen_spec->misc_code_size(); | |
| 128 _reserved.set_end((HeapWord*)(heap_rs.base() + actual_heap_size)); | |
| 129 | |
| 130 _rem_set = collector_policy()->create_rem_set(_reserved, n_covered_regions); | |
| 131 set_barrier_set(rem_set()->bs()); | |
| 132 _gch = this; | |
| 133 | |
| 134 for (i = 0; i < _n_gens; i++) { | |
| 135 ReservedSpace this_rs = heap_rs.first_part(_gen_specs[i]->max_size(), | |
| 136 UseSharedSpaces, UseSharedSpaces); | |
| 137 _gens[i] = _gen_specs[i]->init(this_rs, i, rem_set()); | |
| 138 heap_rs = heap_rs.last_part(_gen_specs[i]->max_size()); | |
| 139 } | |
| 140 _perm_gen = perm_gen_spec->init(heap_rs, PermSize, rem_set()); | |
| 141 | |
| 142 clear_incremental_collection_will_fail(); | |
| 143 clear_last_incremental_collection_failed(); | |
| 144 | |
| 145 #ifndef SERIALGC | |
| 146 // If we are running CMS, create the collector responsible | |
| 147 // for collecting the CMS generations. | |
| 148 if (collector_policy()->is_concurrent_mark_sweep_policy()) { | |
| 149 bool success = create_cms_collector(); | |
| 150 if (!success) return JNI_ENOMEM; | |
| 151 } | |
| 152 #endif // SERIALGC | |
| 153 | |
| 154 return JNI_OK; | |
| 155 } | |
| 156 | |
| 157 | |
| 158 char* GenCollectedHeap::allocate(size_t alignment, | |
| 159 PermanentGenerationSpec* perm_gen_spec, | |
| 160 size_t* _total_reserved, | |
| 161 int* _n_covered_regions, | |
| 162 ReservedSpace* heap_rs){ | |
| 163 const char overflow_msg[] = "The size of the object heap + VM data exceeds " | |
| 164 "the maximum representable size"; | |
| 165 | |
| 166 // Now figure out the total size. | |
| 167 size_t total_reserved = 0; | |
| 168 int n_covered_regions = 0; | |
| 169 const size_t pageSize = UseLargePages ? | |
| 170 os::large_page_size() : os::vm_page_size(); | |
| 171 | |
| 172 for (int i = 0; i < _n_gens; i++) { | |
| 173 total_reserved += _gen_specs[i]->max_size(); | |
| 174 if (total_reserved < _gen_specs[i]->max_size()) { | |
| 175 vm_exit_during_initialization(overflow_msg); | |
| 176 } | |
| 177 n_covered_regions += _gen_specs[i]->n_covered_regions(); | |
| 178 } | |
| 179 assert(total_reserved % pageSize == 0, "Gen size"); | |
| 180 total_reserved += perm_gen_spec->max_size(); | |
| 181 assert(total_reserved % pageSize == 0, "Perm Gen size"); | |
| 182 | |
| 183 if (total_reserved < perm_gen_spec->max_size()) { | |
| 184 vm_exit_during_initialization(overflow_msg); | |
| 185 } | |
| 186 n_covered_regions += perm_gen_spec->n_covered_regions(); | |
| 187 | |
| 188 // Add the size of the data area which shares the same reserved area | |
| 189 // as the heap, but which is not actually part of the heap. | |
| 190 size_t s = perm_gen_spec->misc_data_size() + perm_gen_spec->misc_code_size(); | |
| 191 | |
| 192 total_reserved += s; | |
| 193 if (total_reserved < s) { | |
| 194 vm_exit_during_initialization(overflow_msg); | |
| 195 } | |
| 196 | |
| 197 if (UseLargePages) { | |
| 198 assert(total_reserved != 0, "total_reserved cannot be 0"); | |
| 199 total_reserved = round_to(total_reserved, os::large_page_size()); | |
| 200 if (total_reserved < os::large_page_size()) { | |
| 201 vm_exit_during_initialization(overflow_msg); | |
| 202 } | |
| 203 } | |
| 204 | |
| 205 // Calculate the address at which the heap must reside in order for | |
| 206 // the shared data to be at the required address. | |
| 207 | |
| 208 char* heap_address; | |
| 209 if (UseSharedSpaces) { | |
| 210 | |
| 211 // Calculate the address of the first word beyond the heap. | |
| 212 FileMapInfo* mapinfo = FileMapInfo::current_info(); | |
| 213 int lr = CompactingPermGenGen::n_regions - 1; | |
| 214 size_t capacity = align_size_up(mapinfo->space_capacity(lr), alignment); | |
| 215 heap_address = mapinfo->region_base(lr) + capacity; | |
| 216 | |
| 217 // Calculate the address of the first word of the heap. | |
| 218 heap_address -= total_reserved; | |
| 219 } else { | |
| 220 heap_address = NULL; // any address will do. | |
| 221 } | |
| 222 | |
| 223 *_total_reserved = total_reserved; | |
| 224 *_n_covered_regions = n_covered_regions; | |
|
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225 *heap_rs = ReservedHeapSpace(total_reserved, alignment, |
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226 UseLargePages, heap_address); |
| 0 | 227 |
| 228 return heap_address; | |
| 229 } | |
| 230 | |
| 231 | |
| 232 void GenCollectedHeap::post_initialize() { | |
| 233 SharedHeap::post_initialize(); | |
| 234 TwoGenerationCollectorPolicy *policy = | |
| 235 (TwoGenerationCollectorPolicy *)collector_policy(); | |
| 236 guarantee(policy->is_two_generation_policy(), "Illegal policy type"); | |
| 237 DefNewGeneration* def_new_gen = (DefNewGeneration*) get_gen(0); | |
| 238 assert(def_new_gen->kind() == Generation::DefNew || | |
| 239 def_new_gen->kind() == Generation::ParNew || | |
| 240 def_new_gen->kind() == Generation::ASParNew, | |
| 241 "Wrong generation kind"); | |
| 242 | |
| 243 Generation* old_gen = get_gen(1); | |
| 244 assert(old_gen->kind() == Generation::ConcurrentMarkSweep || | |
| 245 old_gen->kind() == Generation::ASConcurrentMarkSweep || | |
| 246 old_gen->kind() == Generation::MarkSweepCompact, | |
| 247 "Wrong generation kind"); | |
| 248 | |
| 249 policy->initialize_size_policy(def_new_gen->eden()->capacity(), | |
| 250 old_gen->capacity(), | |
| 251 def_new_gen->from()->capacity()); | |
| 252 policy->initialize_gc_policy_counters(); | |
| 253 } | |
| 254 | |
| 255 void GenCollectedHeap::ref_processing_init() { | |
| 256 SharedHeap::ref_processing_init(); | |
| 257 for (int i = 0; i < _n_gens; i++) { | |
| 258 _gens[i]->ref_processor_init(); | |
| 259 } | |
| 260 } | |
| 261 | |
| 262 size_t GenCollectedHeap::capacity() const { | |
| 263 size_t res = 0; | |
| 264 for (int i = 0; i < _n_gens; i++) { | |
| 265 res += _gens[i]->capacity(); | |
| 266 } | |
| 267 return res; | |
| 268 } | |
| 269 | |
| 270 size_t GenCollectedHeap::used() const { | |
| 271 size_t res = 0; | |
| 272 for (int i = 0; i < _n_gens; i++) { | |
| 273 res += _gens[i]->used(); | |
| 274 } | |
| 275 return res; | |
| 276 } | |
| 277 | |
| 278 // Save the "used_region" for generations level and lower, | |
| 279 // and, if perm is true, for perm gen. | |
| 280 void GenCollectedHeap::save_used_regions(int level, bool perm) { | |
| 281 assert(level < _n_gens, "Illegal level parameter"); | |
| 282 for (int i = level; i >= 0; i--) { | |
| 283 _gens[i]->save_used_region(); | |
| 284 } | |
| 285 if (perm) { | |
| 286 perm_gen()->save_used_region(); | |
| 287 } | |
| 288 } | |
| 289 | |
| 290 size_t GenCollectedHeap::max_capacity() const { | |
| 291 size_t res = 0; | |
| 292 for (int i = 0; i < _n_gens; i++) { | |
| 293 res += _gens[i]->max_capacity(); | |
| 294 } | |
| 295 return res; | |
| 296 } | |
| 297 | |
| 298 // Update the _full_collections_completed counter | |
| 299 // at the end of a stop-world full GC. | |
| 300 unsigned int GenCollectedHeap::update_full_collections_completed() { | |
| 301 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); | |
| 302 assert(_full_collections_completed <= _total_full_collections, | |
| 303 "Can't complete more collections than were started"); | |
| 304 _full_collections_completed = _total_full_collections; | |
| 305 ml.notify_all(); | |
| 306 return _full_collections_completed; | |
| 307 } | |
| 308 | |
| 309 // Update the _full_collections_completed counter, as appropriate, | |
| 310 // at the end of a concurrent GC cycle. Note the conditional update | |
| 311 // below to allow this method to be called by a concurrent collector | |
| 312 // without synchronizing in any manner with the VM thread (which | |
| 313 // may already have initiated a STW full collection "concurrently"). | |
| 314 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) { | |
| 315 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag); | |
| 316 assert((_full_collections_completed <= _total_full_collections) && | |
| 317 (count <= _total_full_collections), | |
| 318 "Can't complete more collections than were started"); | |
| 319 if (count > _full_collections_completed) { | |
| 320 _full_collections_completed = count; | |
| 321 ml.notify_all(); | |
| 322 } | |
| 323 return _full_collections_completed; | |
| 324 } | |
| 325 | |
| 326 | |
| 327 #ifndef PRODUCT | |
| 328 // Override of memory state checking method in CollectedHeap: | |
| 329 // Some collectors (CMS for example) can't have badHeapWordVal written | |
| 330 // in the first two words of an object. (For instance , in the case of | |
| 331 // CMS these words hold state used to synchronize between certain | |
| 332 // (concurrent) GC steps and direct allocating mutators.) | |
| 333 // The skip_header_HeapWords() method below, allows us to skip | |
| 334 // over the requisite number of HeapWord's. Note that (for | |
| 335 // generational collectors) this means that those many words are | |
| 336 // skipped in each object, irrespective of the generation in which | |
| 337 // that object lives. The resultant loss of precision seems to be | |
| 338 // harmless and the pain of avoiding that imprecision appears somewhat | |
| 339 // higher than we are prepared to pay for such rudimentary debugging | |
| 340 // support. | |
| 341 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr, | |
| 342 size_t size) { | |
| 343 if (CheckMemoryInitialization && ZapUnusedHeapArea) { | |
| 344 // We are asked to check a size in HeapWords, | |
| 345 // but the memory is mangled in juint words. | |
| 346 juint* start = (juint*) (addr + skip_header_HeapWords()); | |
| 347 juint* end = (juint*) (addr + size); | |
| 348 for (juint* slot = start; slot < end; slot += 1) { | |
| 349 assert(*slot == badHeapWordVal, | |
| 350 "Found non badHeapWordValue in pre-allocation check"); | |
| 351 } | |
| 352 } | |
| 353 } | |
| 354 #endif | |
| 355 | |
| 356 HeapWord* GenCollectedHeap::attempt_allocation(size_t size, | |
| 357 bool is_tlab, | |
| 358 bool first_only) { | |
| 359 HeapWord* res; | |
| 360 for (int i = 0; i < _n_gens; i++) { | |
| 361 if (_gens[i]->should_allocate(size, is_tlab)) { | |
| 362 res = _gens[i]->allocate(size, is_tlab); | |
| 363 if (res != NULL) return res; | |
| 364 else if (first_only) break; | |
| 365 } | |
| 366 } | |
| 367 // Otherwise... | |
| 368 return NULL; | |
| 369 } | |
| 370 | |
| 371 HeapWord* GenCollectedHeap::mem_allocate(size_t size, | |
| 372 bool is_large_noref, | |
| 373 bool is_tlab, | |
| 374 bool* gc_overhead_limit_was_exceeded) { | |
| 375 return collector_policy()->mem_allocate_work(size, | |
| 376 is_tlab, | |
| 377 gc_overhead_limit_was_exceeded); | |
| 378 } | |
| 379 | |
| 380 bool GenCollectedHeap::must_clear_all_soft_refs() { | |
| 381 return _gc_cause == GCCause::_last_ditch_collection; | |
| 382 } | |
| 383 | |
| 384 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) { | |
| 385 return (cause == GCCause::_java_lang_system_gc || | |
| 386 cause == GCCause::_gc_locker) && | |
| 387 UseConcMarkSweepGC && ExplicitGCInvokesConcurrent; | |
| 388 } | |
| 389 | |
| 390 void GenCollectedHeap::do_collection(bool full, | |
| 391 bool clear_all_soft_refs, | |
| 392 size_t size, | |
| 393 bool is_tlab, | |
| 394 int max_level) { | |
| 395 bool prepared_for_verification = false; | |
| 396 ResourceMark rm; | |
| 397 DEBUG_ONLY(Thread* my_thread = Thread::current();) | |
| 398 | |
| 399 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); | |
| 400 assert(my_thread->is_VM_thread() || | |
| 401 my_thread->is_ConcurrentGC_thread(), | |
| 402 "incorrect thread type capability"); | |
| 403 assert(Heap_lock->is_locked(), "the requesting thread should have the Heap_lock"); | |
| 404 guarantee(!is_gc_active(), "collection is not reentrant"); | |
| 405 assert(max_level < n_gens(), "sanity check"); | |
| 406 | |
| 407 if (GC_locker::check_active_before_gc()) { | |
| 408 return; // GC is disabled (e.g. JNI GetXXXCritical operation) | |
| 409 } | |
| 410 | |
| 411 const size_t perm_prev_used = perm_gen()->used(); | |
| 412 | |
| 413 if (PrintHeapAtGC) { | |
| 414 Universe::print_heap_before_gc(); | |
| 415 if (Verbose) { | |
| 416 gclog_or_tty->print_cr("GC Cause: %s", GCCause::to_string(gc_cause())); | |
| 417 } | |
| 418 } | |
| 419 | |
| 420 { | |
| 421 FlagSetting fl(_is_gc_active, true); | |
| 422 | |
| 423 bool complete = full && (max_level == (n_gens()-1)); | |
| 424 const char* gc_cause_str = "GC "; | |
| 425 if (complete) { | |
| 426 GCCause::Cause cause = gc_cause(); | |
| 427 if (cause == GCCause::_java_lang_system_gc) { | |
| 428 gc_cause_str = "Full GC (System) "; | |
| 429 } else { | |
| 430 gc_cause_str = "Full GC "; | |
| 431 } | |
| 432 } | |
| 433 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); | |
| 434 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); | |
| 435 TraceTime t(gc_cause_str, PrintGCDetails, false, gclog_or_tty); | |
| 436 | |
| 437 gc_prologue(complete); | |
| 438 increment_total_collections(complete); | |
| 439 | |
| 440 size_t gch_prev_used = used(); | |
| 441 | |
| 442 int starting_level = 0; | |
| 443 if (full) { | |
| 444 // Search for the oldest generation which will collect all younger | |
| 445 // generations, and start collection loop there. | |
| 446 for (int i = max_level; i >= 0; i--) { | |
| 447 if (_gens[i]->full_collects_younger_generations()) { | |
| 448 starting_level = i; | |
| 449 break; | |
| 450 } | |
| 451 } | |
| 452 } | |
| 453 | |
| 454 bool must_restore_marks_for_biased_locking = false; | |
| 455 | |
| 456 int max_level_collected = starting_level; | |
| 457 for (int i = starting_level; i <= max_level; i++) { | |
| 458 if (_gens[i]->should_collect(full, size, is_tlab)) { | |
| 459 // Timer for individual generations. Last argument is false: no CR | |
| 460 TraceTime t1(_gens[i]->short_name(), PrintGCDetails, false, gclog_or_tty); | |
| 461 TraceCollectorStats tcs(_gens[i]->counters()); | |
| 462 TraceMemoryManagerStats tmms(_gens[i]->kind()); | |
| 463 | |
| 464 size_t prev_used = _gens[i]->used(); | |
| 465 _gens[i]->stat_record()->invocations++; | |
| 466 _gens[i]->stat_record()->accumulated_time.start(); | |
| 467 | |
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468 // Must be done anew before each collection because |
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469 // a previous collection will do mangling and will |
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470 // change top of some spaces. |
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471 record_gen_tops_before_GC(); |
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472 |
| 0 | 473 if (PrintGC && Verbose) { |
| 474 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT, | |
| 475 i, | |
| 476 _gens[i]->stat_record()->invocations, | |
| 477 size*HeapWordSize); | |
| 478 } | |
| 479 | |
| 480 if (VerifyBeforeGC && i >= VerifyGCLevel && | |
| 481 total_collections() >= VerifyGCStartAt) { | |
| 482 HandleMark hm; // Discard invalid handles created during verification | |
| 483 if (!prepared_for_verification) { | |
| 484 prepare_for_verify(); | |
| 485 prepared_for_verification = true; | |
| 486 } | |
| 487 gclog_or_tty->print(" VerifyBeforeGC:"); | |
| 488 Universe::verify(true); | |
| 489 } | |
| 490 COMPILER2_PRESENT(DerivedPointerTable::clear()); | |
| 491 | |
| 492 if (!must_restore_marks_for_biased_locking && | |
| 493 _gens[i]->performs_in_place_marking()) { | |
| 494 // We perform this mark word preservation work lazily | |
| 495 // because it's only at this point that we know whether we | |
| 496 // absolutely have to do it; we want to avoid doing it for | |
| 497 // scavenge-only collections where it's unnecessary | |
| 498 must_restore_marks_for_biased_locking = true; | |
| 499 BiasedLocking::preserve_marks(); | |
| 500 } | |
| 501 | |
| 502 // Do collection work | |
| 503 { | |
| 504 // Note on ref discovery: For what appear to be historical reasons, | |
| 505 // GCH enables and disabled (by enqueing) refs discovery. | |
| 506 // In the future this should be moved into the generation's | |
| 507 // collect method so that ref discovery and enqueueing concerns | |
| 508 // are local to a generation. The collect method could return | |
| 509 // an appropriate indication in the case that notification on | |
| 510 // the ref lock was needed. This will make the treatment of | |
| 511 // weak refs more uniform (and indeed remove such concerns | |
| 512 // from GCH). XXX | |
| 513 | |
| 514 HandleMark hm; // Discard invalid handles created during gc | |
| 515 save_marks(); // save marks for all gens | |
| 516 // We want to discover references, but not process them yet. | |
| 517 // This mode is disabled in process_discovered_references if the | |
| 518 // generation does some collection work, or in | |
| 519 // enqueue_discovered_references if the generation returns | |
| 520 // without doing any work. | |
| 521 ReferenceProcessor* rp = _gens[i]->ref_processor(); | |
| 522 // If the discovery of ("weak") refs in this generation is | |
| 523 // atomic wrt other collectors in this configuration, we | |
| 524 // are guaranteed to have empty discovered ref lists. | |
| 525 if (rp->discovery_is_atomic()) { | |
| 526 rp->verify_no_references_recorded(); | |
| 527 rp->enable_discovery(); | |
| 528 } else { | |
| 529 // collect() will enable discovery as appropriate | |
| 530 } | |
| 531 _gens[i]->collect(full, clear_all_soft_refs, size, is_tlab); | |
| 532 if (!rp->enqueuing_is_done()) { | |
| 533 rp->enqueue_discovered_references(); | |
| 534 } else { | |
| 535 rp->set_enqueuing_is_done(false); | |
| 536 } | |
| 537 rp->verify_no_references_recorded(); | |
| 538 } | |
| 539 max_level_collected = i; | |
| 540 | |
| 541 // Determine if allocation request was met. | |
| 542 if (size > 0) { | |
| 543 if (!is_tlab || _gens[i]->supports_tlab_allocation()) { | |
| 544 if (size*HeapWordSize <= _gens[i]->unsafe_max_alloc_nogc()) { | |
| 545 size = 0; | |
| 546 } | |
| 547 } | |
| 548 } | |
| 549 | |
| 550 COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); | |
| 551 | |
| 552 _gens[i]->stat_record()->accumulated_time.stop(); | |
| 553 | |
| 554 update_gc_stats(i, full); | |
| 555 | |
| 556 if (VerifyAfterGC && i >= VerifyGCLevel && | |
| 557 total_collections() >= VerifyGCStartAt) { | |
| 558 HandleMark hm; // Discard invalid handles created during verification | |
| 559 gclog_or_tty->print(" VerifyAfterGC:"); | |
| 560 Universe::verify(false); | |
| 561 } | |
| 562 | |
| 563 if (PrintGCDetails) { | |
| 564 gclog_or_tty->print(":"); | |
| 565 _gens[i]->print_heap_change(prev_used); | |
| 566 } | |
| 567 } | |
| 568 } | |
| 569 | |
| 570 // Update "complete" boolean wrt what actually transpired -- | |
| 571 // for instance, a promotion failure could have led to | |
| 572 // a whole heap collection. | |
| 573 complete = complete || (max_level_collected == n_gens() - 1); | |
| 574 | |
| 575 if (PrintGCDetails) { | |
| 576 print_heap_change(gch_prev_used); | |
| 577 | |
| 578 // Print perm gen info for full GC with PrintGCDetails flag. | |
| 579 if (complete) { | |
| 580 print_perm_heap_change(perm_prev_used); | |
| 581 } | |
| 582 } | |
| 583 | |
| 584 for (int j = max_level_collected; j >= 0; j -= 1) { | |
| 585 // Adjust generation sizes. | |
| 586 _gens[j]->compute_new_size(); | |
| 587 } | |
| 588 | |
| 589 if (complete) { | |
| 590 // Ask the permanent generation to adjust size for full collections | |
| 591 perm()->compute_new_size(); | |
| 592 update_full_collections_completed(); | |
| 593 } | |
| 594 | |
| 595 // Track memory usage and detect low memory after GC finishes | |
| 596 MemoryService::track_memory_usage(); | |
| 597 | |
| 598 gc_epilogue(complete); | |
| 599 | |
| 600 if (must_restore_marks_for_biased_locking) { | |
| 601 BiasedLocking::restore_marks(); | |
| 602 } | |
| 603 } | |
| 604 | |
| 605 AdaptiveSizePolicy* sp = gen_policy()->size_policy(); | |
| 606 AdaptiveSizePolicyOutput(sp, total_collections()); | |
| 607 | |
| 608 if (PrintHeapAtGC) { | |
| 609 Universe::print_heap_after_gc(); | |
| 610 } | |
| 611 | |
| 612 if (ExitAfterGCNum > 0 && total_collections() == ExitAfterGCNum) { | |
| 613 tty->print_cr("Stopping after GC #%d", ExitAfterGCNum); | |
| 614 vm_exit(-1); | |
| 615 } | |
| 616 } | |
| 617 | |
| 618 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) { | |
| 619 return collector_policy()->satisfy_failed_allocation(size, is_tlab); | |
| 620 } | |
| 621 | |
| 622 void GenCollectedHeap::set_par_threads(int t) { | |
| 623 SharedHeap::set_par_threads(t); | |
| 624 _gen_process_strong_tasks->set_par_threads(t); | |
| 625 } | |
| 626 | |
| 627 class AssertIsPermClosure: public OopClosure { | |
| 628 public: | |
| 629 void do_oop(oop* p) { | |
| 630 assert((*p) == NULL || (*p)->is_perm(), "Referent should be perm."); | |
| 631 } | |
|
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632 void do_oop(narrowOop* p) { ShouldNotReachHere(); } |
| 0 | 633 }; |
| 634 static AssertIsPermClosure assert_is_perm_closure; | |
| 635 | |
| 636 void GenCollectedHeap:: | |
| 637 gen_process_strong_roots(int level, | |
| 638 bool younger_gens_as_roots, | |
| 639 bool collecting_perm_gen, | |
| 640 SharedHeap::ScanningOption so, | |
| 641 OopsInGenClosure* older_gens, | |
| 642 OopsInGenClosure* not_older_gens) { | |
| 643 // General strong roots. | |
| 644 SharedHeap::process_strong_roots(collecting_perm_gen, so, | |
| 645 not_older_gens, older_gens); | |
| 646 | |
| 647 if (younger_gens_as_roots) { | |
| 648 if (!_gen_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) { | |
| 649 for (int i = 0; i < level; i++) { | |
| 650 not_older_gens->set_generation(_gens[i]); | |
| 651 _gens[i]->oop_iterate(not_older_gens); | |
| 652 } | |
| 653 not_older_gens->reset_generation(); | |
| 654 } | |
| 655 } | |
| 656 // When collection is parallel, all threads get to cooperate to do | |
| 657 // older-gen scanning. | |
| 658 for (int i = level+1; i < _n_gens; i++) { | |
| 659 older_gens->set_generation(_gens[i]); | |
| 660 rem_set()->younger_refs_iterate(_gens[i], older_gens); | |
| 661 older_gens->reset_generation(); | |
| 662 } | |
| 663 | |
| 664 _gen_process_strong_tasks->all_tasks_completed(); | |
| 665 } | |
| 666 | |
| 667 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure, | |
| 668 OopClosure* non_root_closure) { | |
| 669 SharedHeap::process_weak_roots(root_closure, non_root_closure); | |
| 670 // "Local" "weak" refs | |
| 671 for (int i = 0; i < _n_gens; i++) { | |
| 672 _gens[i]->ref_processor()->weak_oops_do(root_closure); | |
| 673 } | |
| 674 } | |
| 675 | |
| 676 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \ | |
| 677 void GenCollectedHeap:: \ | |
| 678 oop_since_save_marks_iterate(int level, \ | |
| 679 OopClosureType* cur, \ | |
| 680 OopClosureType* older) { \ | |
| 681 _gens[level]->oop_since_save_marks_iterate##nv_suffix(cur); \ | |
| 682 for (int i = level+1; i < n_gens(); i++) { \ | |
| 683 _gens[i]->oop_since_save_marks_iterate##nv_suffix(older); \ | |
| 684 } \ | |
| 685 perm_gen()->oop_since_save_marks_iterate##nv_suffix(older); \ | |
| 686 } | |
| 687 | |
| 688 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN) | |
| 689 | |
| 690 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN | |
| 691 | |
| 692 bool GenCollectedHeap::no_allocs_since_save_marks(int level) { | |
| 693 for (int i = level; i < _n_gens; i++) { | |
| 694 if (!_gens[i]->no_allocs_since_save_marks()) return false; | |
| 695 } | |
| 696 return perm_gen()->no_allocs_since_save_marks(); | |
| 697 } | |
| 698 | |
| 699 bool GenCollectedHeap::supports_inline_contig_alloc() const { | |
| 700 return _gens[0]->supports_inline_contig_alloc(); | |
| 701 } | |
| 702 | |
| 703 HeapWord** GenCollectedHeap::top_addr() const { | |
| 704 return _gens[0]->top_addr(); | |
| 705 } | |
| 706 | |
| 707 HeapWord** GenCollectedHeap::end_addr() const { | |
| 708 return _gens[0]->end_addr(); | |
| 709 } | |
| 710 | |
| 711 size_t GenCollectedHeap::unsafe_max_alloc() { | |
| 712 return _gens[0]->unsafe_max_alloc_nogc(); | |
| 713 } | |
| 714 | |
| 715 // public collection interfaces | |
| 716 | |
| 717 void GenCollectedHeap::collect(GCCause::Cause cause) { | |
| 718 if (should_do_concurrent_full_gc(cause)) { | |
| 719 #ifndef SERIALGC | |
| 720 // mostly concurrent full collection | |
| 721 collect_mostly_concurrent(cause); | |
| 722 #else // SERIALGC | |
| 723 ShouldNotReachHere(); | |
| 724 #endif // SERIALGC | |
| 725 } else { | |
| 726 #ifdef ASSERT | |
| 727 if (cause == GCCause::_scavenge_alot) { | |
| 728 // minor collection only | |
| 729 collect(cause, 0); | |
| 730 } else { | |
| 731 // Stop-the-world full collection | |
| 732 collect(cause, n_gens() - 1); | |
| 733 } | |
| 734 #else | |
| 735 // Stop-the-world full collection | |
| 736 collect(cause, n_gens() - 1); | |
| 737 #endif | |
| 738 } | |
| 739 } | |
| 740 | |
| 741 void GenCollectedHeap::collect(GCCause::Cause cause, int max_level) { | |
| 742 // The caller doesn't have the Heap_lock | |
| 743 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock"); | |
| 744 MutexLocker ml(Heap_lock); | |
| 745 collect_locked(cause, max_level); | |
| 746 } | |
| 747 | |
| 748 // This interface assumes that it's being called by the | |
| 749 // vm thread. It collects the heap assuming that the | |
| 750 // heap lock is already held and that we are executing in | |
| 751 // the context of the vm thread. | |
| 752 void GenCollectedHeap::collect_as_vm_thread(GCCause::Cause cause) { | |
| 753 assert(Thread::current()->is_VM_thread(), "Precondition#1"); | |
| 754 assert(Heap_lock->is_locked(), "Precondition#2"); | |
| 755 GCCauseSetter gcs(this, cause); | |
| 756 switch (cause) { | |
| 757 case GCCause::_heap_inspection: | |
| 758 case GCCause::_heap_dump: { | |
| 759 HandleMark hm; | |
| 760 do_full_collection(false, // don't clear all soft refs | |
| 761 n_gens() - 1); | |
| 762 break; | |
| 763 } | |
| 764 default: // XXX FIX ME | |
| 765 ShouldNotReachHere(); // Unexpected use of this function | |
| 766 } | |
| 767 } | |
| 768 | |
| 769 void GenCollectedHeap::collect_locked(GCCause::Cause cause) { | |
| 770 // The caller has the Heap_lock | |
| 771 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock"); | |
| 772 collect_locked(cause, n_gens() - 1); | |
| 773 } | |
| 774 | |
| 775 // this is the private collection interface | |
| 776 // The Heap_lock is expected to be held on entry. | |
| 777 | |
| 778 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) { | |
| 779 if (_preloading_shared_classes) { | |
| 780 warning("\nThe permanent generation is not large enough to preload " | |
| 781 "requested classes.\nUse -XX:PermSize= to increase the initial " | |
| 782 "size of the permanent generation.\n"); | |
| 783 vm_exit(2); | |
| 784 } | |
| 785 // Read the GC count while holding the Heap_lock | |
| 786 unsigned int gc_count_before = total_collections(); | |
| 787 unsigned int full_gc_count_before = total_full_collections(); | |
| 788 { | |
| 789 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back | |
| 790 VM_GenCollectFull op(gc_count_before, full_gc_count_before, | |
| 791 cause, max_level); | |
| 792 VMThread::execute(&op); | |
| 793 } | |
| 794 } | |
| 795 | |
| 796 #ifndef SERIALGC | |
| 797 bool GenCollectedHeap::create_cms_collector() { | |
| 798 | |
| 799 assert(((_gens[1]->kind() == Generation::ConcurrentMarkSweep) || | |
| 800 (_gens[1]->kind() == Generation::ASConcurrentMarkSweep)) && | |
| 801 _perm_gen->as_gen()->kind() == Generation::ConcurrentMarkSweep, | |
| 802 "Unexpected generation kinds"); | |
| 803 // Skip two header words in the block content verification | |
| 804 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();) | |
| 805 CMSCollector* collector = new CMSCollector( | |
| 806 (ConcurrentMarkSweepGeneration*)_gens[1], | |
| 807 (ConcurrentMarkSweepGeneration*)_perm_gen->as_gen(), | |
| 808 _rem_set->as_CardTableRS(), | |
| 809 (ConcurrentMarkSweepPolicy*) collector_policy()); | |
| 810 | |
| 811 if (collector == NULL || !collector->completed_initialization()) { | |
| 812 if (collector) { | |
| 813 delete collector; // Be nice in embedded situation | |
| 814 } | |
| 815 vm_shutdown_during_initialization("Could not create CMS collector"); | |
| 816 return false; | |
| 817 } | |
| 818 return true; // success | |
| 819 } | |
| 820 | |
| 821 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) { | |
| 822 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock"); | |
| 823 | |
| 824 MutexLocker ml(Heap_lock); | |
| 825 // Read the GC counts while holding the Heap_lock | |
| 826 unsigned int full_gc_count_before = total_full_collections(); | |
| 827 unsigned int gc_count_before = total_collections(); | |
| 828 { | |
| 829 MutexUnlocker mu(Heap_lock); | |
| 830 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause); | |
| 831 VMThread::execute(&op); | |
| 832 } | |
| 833 } | |
| 834 #endif // SERIALGC | |
| 835 | |
| 836 | |
| 837 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs, | |
| 838 int max_level) { | |
| 839 int local_max_level; | |
| 840 if (!incremental_collection_will_fail() && | |
| 841 gc_cause() == GCCause::_gc_locker) { | |
| 842 local_max_level = 0; | |
| 843 } else { | |
| 844 local_max_level = max_level; | |
| 845 } | |
| 846 | |
| 847 do_collection(true /* full */, | |
| 848 clear_all_soft_refs /* clear_all_soft_refs */, | |
| 849 0 /* size */, | |
| 850 false /* is_tlab */, | |
| 851 local_max_level /* max_level */); | |
| 852 // Hack XXX FIX ME !!! | |
| 853 // A scavenge may not have been attempted, or may have | |
| 854 // been attempted and failed, because the old gen was too full | |
| 855 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker && | |
| 856 incremental_collection_will_fail()) { | |
| 857 if (PrintGCDetails) { | |
| 858 gclog_or_tty->print_cr("GC locker: Trying a full collection " | |
| 859 "because scavenge failed"); | |
| 860 } | |
| 861 // This time allow the old gen to be collected as well | |
| 862 do_collection(true /* full */, | |
| 863 clear_all_soft_refs /* clear_all_soft_refs */, | |
| 864 0 /* size */, | |
| 865 false /* is_tlab */, | |
| 866 n_gens() - 1 /* max_level */); | |
| 867 } | |
| 868 } | |
| 869 | |
| 870 // Returns "TRUE" iff "p" points into the allocated area of the heap. | |
| 871 bool GenCollectedHeap::is_in(const void* p) const { | |
| 872 #ifndef ASSERT | |
| 873 guarantee(VerifyBeforeGC || | |
| 874 VerifyDuringGC || | |
| 875 VerifyBeforeExit || | |
| 876 VerifyAfterGC, "too expensive"); | |
| 877 #endif | |
| 878 // This might be sped up with a cache of the last generation that | |
| 879 // answered yes. | |
| 880 for (int i = 0; i < _n_gens; i++) { | |
| 881 if (_gens[i]->is_in(p)) return true; | |
| 882 } | |
| 883 if (_perm_gen->as_gen()->is_in(p)) return true; | |
| 884 // Otherwise... | |
| 885 return false; | |
| 886 } | |
| 887 | |
| 888 // Returns "TRUE" iff "p" points into the allocated area of the heap. | |
| 889 bool GenCollectedHeap::is_in_youngest(void* p) { | |
| 890 return _gens[0]->is_in(p); | |
| 891 } | |
| 892 | |
| 893 void GenCollectedHeap::oop_iterate(OopClosure* cl) { | |
| 894 for (int i = 0; i < _n_gens; i++) { | |
| 895 _gens[i]->oop_iterate(cl); | |
| 896 } | |
| 897 } | |
| 898 | |
| 899 void GenCollectedHeap::oop_iterate(MemRegion mr, OopClosure* cl) { | |
| 900 for (int i = 0; i < _n_gens; i++) { | |
| 901 _gens[i]->oop_iterate(mr, cl); | |
| 902 } | |
| 903 } | |
| 904 | |
| 905 void GenCollectedHeap::object_iterate(ObjectClosure* cl) { | |
| 906 for (int i = 0; i < _n_gens; i++) { | |
| 907 _gens[i]->object_iterate(cl); | |
| 908 } | |
| 909 perm_gen()->object_iterate(cl); | |
| 910 } | |
| 911 | |
| 912 void GenCollectedHeap::object_iterate_since_last_GC(ObjectClosure* cl) { | |
| 913 for (int i = 0; i < _n_gens; i++) { | |
| 914 _gens[i]->object_iterate_since_last_GC(cl); | |
| 915 } | |
| 916 } | |
| 917 | |
| 918 Space* GenCollectedHeap::space_containing(const void* addr) const { | |
| 919 for (int i = 0; i < _n_gens; i++) { | |
| 920 Space* res = _gens[i]->space_containing(addr); | |
| 921 if (res != NULL) return res; | |
| 922 } | |
| 923 Space* res = perm_gen()->space_containing(addr); | |
| 924 if (res != NULL) return res; | |
| 925 // Otherwise... | |
| 926 assert(false, "Could not find containing space"); | |
| 927 return NULL; | |
| 928 } | |
| 929 | |
| 930 | |
| 931 HeapWord* GenCollectedHeap::block_start(const void* addr) const { | |
| 932 assert(is_in_reserved(addr), "block_start of address outside of heap"); | |
| 933 for (int i = 0; i < _n_gens; i++) { | |
| 934 if (_gens[i]->is_in_reserved(addr)) { | |
| 935 assert(_gens[i]->is_in(addr), | |
| 936 "addr should be in allocated part of generation"); | |
| 937 return _gens[i]->block_start(addr); | |
| 938 } | |
| 939 } | |
| 940 if (perm_gen()->is_in_reserved(addr)) { | |
| 941 assert(perm_gen()->is_in(addr), | |
| 942 "addr should be in allocated part of perm gen"); | |
| 943 return perm_gen()->block_start(addr); | |
| 944 } | |
| 945 assert(false, "Some generation should contain the address"); | |
| 946 return NULL; | |
| 947 } | |
| 948 | |
| 949 size_t GenCollectedHeap::block_size(const HeapWord* addr) const { | |
| 950 assert(is_in_reserved(addr), "block_size of address outside of heap"); | |
| 951 for (int i = 0; i < _n_gens; i++) { | |
| 952 if (_gens[i]->is_in_reserved(addr)) { | |
| 953 assert(_gens[i]->is_in(addr), | |
| 954 "addr should be in allocated part of generation"); | |
| 955 return _gens[i]->block_size(addr); | |
| 956 } | |
| 957 } | |
| 958 if (perm_gen()->is_in_reserved(addr)) { | |
| 959 assert(perm_gen()->is_in(addr), | |
| 960 "addr should be in allocated part of perm gen"); | |
| 961 return perm_gen()->block_size(addr); | |
| 962 } | |
| 963 assert(false, "Some generation should contain the address"); | |
| 964 return 0; | |
| 965 } | |
| 966 | |
| 967 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const { | |
| 968 assert(is_in_reserved(addr), "block_is_obj of address outside of heap"); | |
| 969 assert(block_start(addr) == addr, "addr must be a block start"); | |
| 970 for (int i = 0; i < _n_gens; i++) { | |
| 971 if (_gens[i]->is_in_reserved(addr)) { | |
| 972 return _gens[i]->block_is_obj(addr); | |
| 973 } | |
| 974 } | |
| 975 if (perm_gen()->is_in_reserved(addr)) { | |
| 976 return perm_gen()->block_is_obj(addr); | |
| 977 } | |
| 978 assert(false, "Some generation should contain the address"); | |
| 979 return false; | |
| 980 } | |
| 981 | |
| 982 bool GenCollectedHeap::supports_tlab_allocation() const { | |
| 983 for (int i = 0; i < _n_gens; i += 1) { | |
| 984 if (_gens[i]->supports_tlab_allocation()) { | |
| 985 return true; | |
| 986 } | |
| 987 } | |
| 988 return false; | |
| 989 } | |
| 990 | |
| 991 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const { | |
| 992 size_t result = 0; | |
| 993 for (int i = 0; i < _n_gens; i += 1) { | |
| 994 if (_gens[i]->supports_tlab_allocation()) { | |
| 995 result += _gens[i]->tlab_capacity(); | |
| 996 } | |
| 997 } | |
| 998 return result; | |
| 999 } | |
| 1000 | |
| 1001 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const { | |
| 1002 size_t result = 0; | |
| 1003 for (int i = 0; i < _n_gens; i += 1) { | |
| 1004 if (_gens[i]->supports_tlab_allocation()) { | |
| 1005 result += _gens[i]->unsafe_max_tlab_alloc(); | |
| 1006 } | |
| 1007 } | |
| 1008 return result; | |
| 1009 } | |
| 1010 | |
| 1011 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) { | |
| 1012 bool gc_overhead_limit_was_exceeded; | |
| 1013 HeapWord* result = mem_allocate(size /* size */, | |
| 1014 false /* is_large_noref */, | |
| 1015 true /* is_tlab */, | |
| 1016 &gc_overhead_limit_was_exceeded); | |
| 1017 return result; | |
| 1018 } | |
| 1019 | |
| 1020 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size | |
| 1021 // from the list headed by "*prev_ptr". | |
| 1022 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) { | |
| 1023 bool first = true; | |
| 1024 size_t min_size = 0; // "first" makes this conceptually infinite. | |
| 1025 ScratchBlock **smallest_ptr, *smallest; | |
| 1026 ScratchBlock *cur = *prev_ptr; | |
| 1027 while (cur) { | |
| 1028 assert(*prev_ptr == cur, "just checking"); | |
| 1029 if (first || cur->num_words < min_size) { | |
| 1030 smallest_ptr = prev_ptr; | |
| 1031 smallest = cur; | |
| 1032 min_size = smallest->num_words; | |
| 1033 first = false; | |
| 1034 } | |
| 1035 prev_ptr = &cur->next; | |
| 1036 cur = cur->next; | |
| 1037 } | |
| 1038 smallest = *smallest_ptr; | |
| 1039 *smallest_ptr = smallest->next; | |
| 1040 return smallest; | |
| 1041 } | |
| 1042 | |
| 1043 // Sort the scratch block list headed by res into decreasing size order, | |
| 1044 // and set "res" to the result. | |
| 1045 static void sort_scratch_list(ScratchBlock*& list) { | |
| 1046 ScratchBlock* sorted = NULL; | |
| 1047 ScratchBlock* unsorted = list; | |
| 1048 while (unsorted) { | |
| 1049 ScratchBlock *smallest = removeSmallestScratch(&unsorted); | |
| 1050 smallest->next = sorted; | |
| 1051 sorted = smallest; | |
| 1052 } | |
| 1053 list = sorted; | |
| 1054 } | |
| 1055 | |
| 1056 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor, | |
| 1057 size_t max_alloc_words) { | |
| 1058 ScratchBlock* res = NULL; | |
| 1059 for (int i = 0; i < _n_gens; i++) { | |
| 1060 _gens[i]->contribute_scratch(res, requestor, max_alloc_words); | |
| 1061 } | |
| 1062 sort_scratch_list(res); | |
| 1063 return res; | |
| 1064 } | |
| 1065 | |
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1066 void GenCollectedHeap::release_scratch() { |
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1067 for (int i = 0; i < _n_gens; i++) { |
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1068 _gens[i]->reset_scratch(); |
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1069 } |
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1070 } |
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1071 |
| 0 | 1072 size_t GenCollectedHeap::large_typearray_limit() { |
| 1073 return gen_policy()->large_typearray_limit(); | |
| 1074 } | |
| 1075 | |
| 1076 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure { | |
| 1077 void do_generation(Generation* gen) { | |
| 1078 gen->prepare_for_verify(); | |
| 1079 } | |
| 1080 }; | |
| 1081 | |
| 1082 void GenCollectedHeap::prepare_for_verify() { | |
| 1083 ensure_parsability(false); // no need to retire TLABs | |
| 1084 GenPrepareForVerifyClosure blk; | |
| 1085 generation_iterate(&blk, false); | |
| 1086 perm_gen()->prepare_for_verify(); | |
| 1087 } | |
| 1088 | |
| 1089 | |
| 1090 void GenCollectedHeap::generation_iterate(GenClosure* cl, | |
| 1091 bool old_to_young) { | |
| 1092 if (old_to_young) { | |
| 1093 for (int i = _n_gens-1; i >= 0; i--) { | |
| 1094 cl->do_generation(_gens[i]); | |
| 1095 } | |
| 1096 } else { | |
| 1097 for (int i = 0; i < _n_gens; i++) { | |
| 1098 cl->do_generation(_gens[i]); | |
| 1099 } | |
| 1100 } | |
| 1101 } | |
| 1102 | |
| 1103 void GenCollectedHeap::space_iterate(SpaceClosure* cl) { | |
| 1104 for (int i = 0; i < _n_gens; i++) { | |
| 1105 _gens[i]->space_iterate(cl, true); | |
| 1106 } | |
| 1107 perm_gen()->space_iterate(cl, true); | |
| 1108 } | |
| 1109 | |
| 1110 bool GenCollectedHeap::is_maximal_no_gc() const { | |
| 1111 for (int i = 0; i < _n_gens; i++) { // skip perm gen | |
| 1112 if (!_gens[i]->is_maximal_no_gc()) { | |
| 1113 return false; | |
| 1114 } | |
| 1115 } | |
| 1116 return true; | |
| 1117 } | |
| 1118 | |
| 1119 void GenCollectedHeap::save_marks() { | |
| 1120 for (int i = 0; i < _n_gens; i++) { | |
| 1121 _gens[i]->save_marks(); | |
| 1122 } | |
| 1123 perm_gen()->save_marks(); | |
| 1124 } | |
| 1125 | |
| 1126 void GenCollectedHeap::compute_new_generation_sizes(int collectedGen) { | |
| 1127 for (int i = 0; i <= collectedGen; i++) { | |
| 1128 _gens[i]->compute_new_size(); | |
| 1129 } | |
| 1130 } | |
| 1131 | |
| 1132 GenCollectedHeap* GenCollectedHeap::heap() { | |
| 1133 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()"); | |
| 1134 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap"); | |
| 1135 return _gch; | |
| 1136 } | |
| 1137 | |
| 1138 | |
| 1139 void GenCollectedHeap::prepare_for_compaction() { | |
| 1140 Generation* scanning_gen = _gens[_n_gens-1]; | |
| 1141 // Start by compacting into same gen. | |
| 1142 CompactPoint cp(scanning_gen, NULL, NULL); | |
| 1143 while (scanning_gen != NULL) { | |
| 1144 scanning_gen->prepare_for_compaction(&cp); | |
| 1145 scanning_gen = prev_gen(scanning_gen); | |
| 1146 } | |
| 1147 } | |
| 1148 | |
| 1149 GCStats* GenCollectedHeap::gc_stats(int level) const { | |
| 1150 return _gens[level]->gc_stats(); | |
| 1151 } | |
| 1152 | |
| 1153 void GenCollectedHeap::verify(bool allow_dirty, bool silent) { | |
| 1154 if (!silent) { | |
| 1155 gclog_or_tty->print("permgen "); | |
| 1156 } | |
| 1157 perm_gen()->verify(allow_dirty); | |
| 1158 for (int i = _n_gens-1; i >= 0; i--) { | |
| 1159 Generation* g = _gens[i]; | |
| 1160 if (!silent) { | |
| 1161 gclog_or_tty->print(g->name()); | |
| 1162 gclog_or_tty->print(" "); | |
| 1163 } | |
| 1164 g->verify(allow_dirty); | |
| 1165 } | |
| 1166 if (!silent) { | |
| 1167 gclog_or_tty->print("remset "); | |
| 1168 } | |
| 1169 rem_set()->verify(); | |
| 1170 if (!silent) { | |
| 1171 gclog_or_tty->print("ref_proc "); | |
| 1172 } | |
| 1173 ReferenceProcessor::verify(); | |
| 1174 } | |
| 1175 | |
| 1176 void GenCollectedHeap::print() const { print_on(tty); } | |
| 1177 void GenCollectedHeap::print_on(outputStream* st) const { | |
| 1178 for (int i = 0; i < _n_gens; i++) { | |
| 1179 _gens[i]->print_on(st); | |
| 1180 } | |
| 1181 perm_gen()->print_on(st); | |
| 1182 } | |
| 1183 | |
| 1184 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const { | |
| 1185 if (workers() != NULL) { | |
| 1186 workers()->threads_do(tc); | |
| 1187 } | |
| 1188 #ifndef SERIALGC | |
| 1189 if (UseConcMarkSweepGC) { | |
| 1190 ConcurrentMarkSweepThread::threads_do(tc); | |
| 1191 } | |
| 1192 #endif // SERIALGC | |
| 1193 } | |
| 1194 | |
| 1195 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const { | |
| 1196 #ifndef SERIALGC | |
| 1197 if (UseParNewGC) { | |
| 1198 workers()->print_worker_threads_on(st); | |
| 1199 } | |
| 1200 if (UseConcMarkSweepGC) { | |
| 1201 ConcurrentMarkSweepThread::print_all_on(st); | |
| 1202 } | |
| 1203 #endif // SERIALGC | |
| 1204 } | |
| 1205 | |
| 1206 void GenCollectedHeap::print_tracing_info() const { | |
| 1207 if (TraceGen0Time) { | |
| 1208 get_gen(0)->print_summary_info(); | |
| 1209 } | |
| 1210 if (TraceGen1Time) { | |
| 1211 get_gen(1)->print_summary_info(); | |
| 1212 } | |
| 1213 } | |
| 1214 | |
| 1215 void GenCollectedHeap::print_heap_change(size_t prev_used) const { | |
| 1216 if (PrintGCDetails && Verbose) { | |
| 1217 gclog_or_tty->print(" " SIZE_FORMAT | |
| 1218 "->" SIZE_FORMAT | |
| 1219 "(" SIZE_FORMAT ")", | |
| 1220 prev_used, used(), capacity()); | |
| 1221 } else { | |
| 1222 gclog_or_tty->print(" " SIZE_FORMAT "K" | |
| 1223 "->" SIZE_FORMAT "K" | |
| 1224 "(" SIZE_FORMAT "K)", | |
| 1225 prev_used / K, used() / K, capacity() / K); | |
| 1226 } | |
| 1227 } | |
| 1228 | |
| 1229 //New method to print perm gen info with PrintGCDetails flag | |
| 1230 void GenCollectedHeap::print_perm_heap_change(size_t perm_prev_used) const { | |
| 1231 gclog_or_tty->print(", [%s :", perm_gen()->short_name()); | |
| 1232 perm_gen()->print_heap_change(perm_prev_used); | |
| 1233 gclog_or_tty->print("]"); | |
| 1234 } | |
| 1235 | |
| 1236 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure { | |
| 1237 private: | |
| 1238 bool _full; | |
| 1239 public: | |
| 1240 void do_generation(Generation* gen) { | |
| 1241 gen->gc_prologue(_full); | |
| 1242 } | |
| 1243 GenGCPrologueClosure(bool full) : _full(full) {}; | |
| 1244 }; | |
| 1245 | |
| 1246 void GenCollectedHeap::gc_prologue(bool full) { | |
| 1247 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer"); | |
| 1248 | |
| 1249 always_do_update_barrier = false; | |
| 1250 // Fill TLAB's and such | |
| 1251 CollectedHeap::accumulate_statistics_all_tlabs(); | |
| 1252 ensure_parsability(true); // retire TLABs | |
| 1253 | |
| 1254 // Call allocation profiler | |
| 1255 AllocationProfiler::iterate_since_last_gc(); | |
| 1256 // Walk generations | |
| 1257 GenGCPrologueClosure blk(full); | |
| 1258 generation_iterate(&blk, false); // not old-to-young. | |
| 1259 perm_gen()->gc_prologue(full); | |
| 1260 }; | |
| 1261 | |
| 1262 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure { | |
| 1263 private: | |
| 1264 bool _full; | |
| 1265 public: | |
| 1266 void do_generation(Generation* gen) { | |
| 1267 gen->gc_epilogue(_full); | |
| 1268 } | |
| 1269 GenGCEpilogueClosure(bool full) : _full(full) {}; | |
| 1270 }; | |
| 1271 | |
| 1272 void GenCollectedHeap::gc_epilogue(bool full) { | |
| 1273 // Remember if a partial collection of the heap failed, and | |
| 1274 // we did a complete collection. | |
| 1275 if (full && incremental_collection_will_fail()) { | |
| 1276 set_last_incremental_collection_failed(); | |
| 1277 } else { | |
| 1278 clear_last_incremental_collection_failed(); | |
| 1279 } | |
| 1280 // Clear the flag, if set; the generation gc_epilogues will set the | |
| 1281 // flag again if the condition persists despite the collection. | |
| 1282 clear_incremental_collection_will_fail(); | |
| 1283 | |
| 1284 #ifdef COMPILER2 | |
| 1285 assert(DerivedPointerTable::is_empty(), "derived pointer present"); | |
| 1286 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr())); | |
| 1287 guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps"); | |
| 1288 #endif /* COMPILER2 */ | |
| 1289 | |
| 1290 resize_all_tlabs(); | |
| 1291 | |
| 1292 GenGCEpilogueClosure blk(full); | |
| 1293 generation_iterate(&blk, false); // not old-to-young. | |
| 1294 perm_gen()->gc_epilogue(full); | |
| 1295 | |
| 1296 always_do_update_barrier = UseConcMarkSweepGC; | |
| 1297 }; | |
| 1298 | |
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1299 #ifndef PRODUCT |
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1300 class GenGCSaveTopsBeforeGCClosure: public GenCollectedHeap::GenClosure { |
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1301 private: |
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1302 public: |
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1303 void do_generation(Generation* gen) { |
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1304 gen->record_spaces_top(); |
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1305 } |
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1306 }; |
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1307 |
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1308 void GenCollectedHeap::record_gen_tops_before_GC() { |
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1309 if (ZapUnusedHeapArea) { |
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1310 GenGCSaveTopsBeforeGCClosure blk; |
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1311 generation_iterate(&blk, false); // not old-to-young. |
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1312 perm_gen()->record_spaces_top(); |
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1313 } |
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1314 } |
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1315 #endif // not PRODUCT |
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1316 |
| 0 | 1317 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure { |
| 1318 public: | |
| 1319 void do_generation(Generation* gen) { | |
| 1320 gen->ensure_parsability(); | |
| 1321 } | |
| 1322 }; | |
| 1323 | |
| 1324 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) { | |
| 1325 CollectedHeap::ensure_parsability(retire_tlabs); | |
| 1326 GenEnsureParsabilityClosure ep_cl; | |
| 1327 generation_iterate(&ep_cl, false); | |
| 1328 perm_gen()->ensure_parsability(); | |
| 1329 } | |
| 1330 | |
| 1331 oop GenCollectedHeap::handle_failed_promotion(Generation* gen, | |
| 1332 oop obj, | |
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1333 size_t obj_size) { |
| 0 | 1334 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in"); |
| 1335 HeapWord* result = NULL; | |
| 1336 | |
| 1337 // First give each higher generation a chance to allocate the promoted object. | |
| 1338 Generation* allocator = next_gen(gen); | |
| 1339 if (allocator != NULL) { | |
| 1340 do { | |
| 1341 result = allocator->allocate(obj_size, false); | |
| 1342 } while (result == NULL && (allocator = next_gen(allocator)) != NULL); | |
| 1343 } | |
| 1344 | |
| 1345 if (result == NULL) { | |
| 1346 // Then give gen and higher generations a chance to expand and allocate the | |
| 1347 // object. | |
| 1348 do { | |
| 1349 result = gen->expand_and_allocate(obj_size, false); | |
| 1350 } while (result == NULL && (gen = next_gen(gen)) != NULL); | |
| 1351 } | |
| 1352 | |
| 1353 if (result != NULL) { | |
| 1354 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size); | |
| 1355 } | |
| 1356 return oop(result); | |
| 1357 } | |
| 1358 | |
| 1359 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure { | |
| 1360 jlong _time; // in ms | |
| 1361 jlong _now; // in ms | |
| 1362 | |
| 1363 public: | |
| 1364 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { } | |
| 1365 | |
| 1366 jlong time() { return _time; } | |
| 1367 | |
| 1368 void do_generation(Generation* gen) { | |
| 1369 _time = MIN2(_time, gen->time_of_last_gc(_now)); | |
| 1370 } | |
| 1371 }; | |
| 1372 | |
| 1373 jlong GenCollectedHeap::millis_since_last_gc() { | |
| 1374 jlong now = os::javaTimeMillis(); | |
| 1375 GenTimeOfLastGCClosure tolgc_cl(now); | |
| 1376 // iterate over generations getting the oldest | |
| 1377 // time that a generation was collected | |
| 1378 generation_iterate(&tolgc_cl, false); | |
| 1379 tolgc_cl.do_generation(perm_gen()); | |
| 1380 // XXX Despite the assert above, since javaTimeMillis() | |
| 1381 // doesnot guarantee monotonically increasing return | |
| 1382 // values (note, i didn't say "strictly monotonic"), | |
| 1383 // we need to guard against getting back a time | |
| 1384 // later than now. This should be fixed by basing | |
| 1385 // on someting like gethrtime() which guarantees | |
| 1386 // monotonicity. Note that cond_wait() is susceptible | |
| 1387 // to a similar problem, because its interface is | |
| 1388 // based on absolute time in the form of the | |
| 1389 // system time's notion of UCT. See also 4506635 | |
| 1390 // for yet another problem of similar nature. XXX | |
| 1391 jlong retVal = now - tolgc_cl.time(); | |
| 1392 if (retVal < 0) { | |
| 1393 NOT_PRODUCT(warning("time warp: %d", retVal);) | |
| 1394 return 0; | |
| 1395 } | |
| 1396 return retVal; | |
| 1397 } |