annotate src/share/vm/memory/genCollectedHeap.cpp @ 196:d1605aabd0a1

6719955: Update copyright year Summary: Update copyright year for files that have been modified in 2008 Reviewed-by: ohair, tbell
author xdono
date Wed, 02 Jul 2008 12:55:16 -0700
parents ba764ed4b6f2
children 1fdb98a17101
rev   line source
duke@0 1 /*
xdono@196 2 * Copyright 2000-2008 Sun Microsystems, Inc. All Rights Reserved.
duke@0 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
duke@0 4 *
duke@0 5 * This code is free software; you can redistribute it and/or modify it
duke@0 6 * under the terms of the GNU General Public License version 2 only, as
duke@0 7 * published by the Free Software Foundation.
duke@0 8 *
duke@0 9 * This code is distributed in the hope that it will be useful, but WITHOUT
duke@0 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
duke@0 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
duke@0 12 * version 2 for more details (a copy is included in the LICENSE file that
duke@0 13 * accompanied this code).
duke@0 14 *
duke@0 15 * You should have received a copy of the GNU General Public License version
duke@0 16 * 2 along with this work; if not, write to the Free Software Foundation,
duke@0 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
duke@0 18 *
duke@0 19 * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
duke@0 20 * CA 95054 USA or visit www.sun.com if you need additional information or
duke@0 21 * have any questions.
duke@0 22 *
duke@0 23 */
duke@0 24
duke@0 25 # include "incls/_precompiled.incl"
duke@0 26 # include "incls/_genCollectedHeap.cpp.incl"
duke@0 27
duke@0 28 GenCollectedHeap* GenCollectedHeap::_gch;
duke@0 29 NOT_PRODUCT(size_t GenCollectedHeap::_skip_header_HeapWords = 0;)
duke@0 30
duke@0 31 // The set of potentially parallel tasks in strong root scanning.
duke@0 32 enum GCH_process_strong_roots_tasks {
duke@0 33 // We probably want to parallelize both of these internally, but for now...
duke@0 34 GCH_PS_younger_gens,
duke@0 35 // Leave this one last.
duke@0 36 GCH_PS_NumElements
duke@0 37 };
duke@0 38
duke@0 39 GenCollectedHeap::GenCollectedHeap(GenCollectorPolicy *policy) :
duke@0 40 SharedHeap(policy),
duke@0 41 _gen_policy(policy),
duke@0 42 _gen_process_strong_tasks(new SubTasksDone(GCH_PS_NumElements)),
duke@0 43 _full_collections_completed(0)
duke@0 44 {
duke@0 45 if (_gen_process_strong_tasks == NULL ||
duke@0 46 !_gen_process_strong_tasks->valid()) {
duke@0 47 vm_exit_during_initialization("Failed necessary allocation.");
duke@0 48 }
duke@0 49 assert(policy != NULL, "Sanity check");
duke@0 50 _preloading_shared_classes = false;
duke@0 51 }
duke@0 52
duke@0 53 jint GenCollectedHeap::initialize() {
duke@0 54 int i;
duke@0 55 _n_gens = gen_policy()->number_of_generations();
duke@0 56
duke@0 57 // While there are no constraints in the GC code that HeapWordSize
duke@0 58 // be any particular value, there are multiple other areas in the
duke@0 59 // system which believe this to be true (e.g. oop->object_size in some
duke@0 60 // cases incorrectly returns the size in wordSize units rather than
duke@0 61 // HeapWordSize).
duke@0 62 guarantee(HeapWordSize == wordSize, "HeapWordSize must equal wordSize");
duke@0 63
duke@0 64 // The heap must be at least as aligned as generations.
duke@0 65 size_t alignment = Generation::GenGrain;
duke@0 66
duke@0 67 _gen_specs = gen_policy()->generations();
duke@0 68 PermanentGenerationSpec *perm_gen_spec =
duke@0 69 collector_policy()->permanent_generation();
duke@0 70
duke@0 71 // Make sure the sizes are all aligned.
duke@0 72 for (i = 0; i < _n_gens; i++) {
duke@0 73 _gen_specs[i]->align(alignment);
duke@0 74 }
duke@0 75 perm_gen_spec->align(alignment);
duke@0 76
duke@0 77 // If we are dumping the heap, then allocate a wasted block of address
duke@0 78 // space in order to push the heap to a lower address. This extra
duke@0 79 // address range allows for other (or larger) libraries to be loaded
duke@0 80 // without them occupying the space required for the shared spaces.
duke@0 81
duke@0 82 if (DumpSharedSpaces) {
duke@0 83 uintx reserved = 0;
duke@0 84 uintx block_size = 64*1024*1024;
duke@0 85 while (reserved < SharedDummyBlockSize) {
duke@0 86 char* dummy = os::reserve_memory(block_size);
duke@0 87 reserved += block_size;
duke@0 88 }
duke@0 89 }
duke@0 90
duke@0 91 // Allocate space for the heap.
duke@0 92
duke@0 93 char* heap_address;
duke@0 94 size_t total_reserved = 0;
duke@0 95 int n_covered_regions = 0;
duke@0 96 ReservedSpace heap_rs(0);
duke@0 97
duke@0 98 heap_address = allocate(alignment, perm_gen_spec, &total_reserved,
duke@0 99 &n_covered_regions, &heap_rs);
duke@0 100
duke@0 101 if (UseSharedSpaces) {
duke@0 102 if (!heap_rs.is_reserved() || heap_address != heap_rs.base()) {
duke@0 103 if (heap_rs.is_reserved()) {
duke@0 104 heap_rs.release();
duke@0 105 }
duke@0 106 FileMapInfo* mapinfo = FileMapInfo::current_info();
duke@0 107 mapinfo->fail_continue("Unable to reserve shared region.");
duke@0 108 allocate(alignment, perm_gen_spec, &total_reserved, &n_covered_regions,
duke@0 109 &heap_rs);
duke@0 110 }
duke@0 111 }
duke@0 112
duke@0 113 if (!heap_rs.is_reserved()) {
duke@0 114 vm_shutdown_during_initialization(
duke@0 115 "Could not reserve enough space for object heap");
duke@0 116 return JNI_ENOMEM;
duke@0 117 }
duke@0 118
duke@0 119 _reserved = MemRegion((HeapWord*)heap_rs.base(),
duke@0 120 (HeapWord*)(heap_rs.base() + heap_rs.size()));
duke@0 121
duke@0 122 // It is important to do this in a way such that concurrent readers can't
duke@0 123 // temporarily think somethings in the heap. (Seen this happen in asserts.)
duke@0 124 _reserved.set_word_size(0);
duke@0 125 _reserved.set_start((HeapWord*)heap_rs.base());
duke@0 126 size_t actual_heap_size = heap_rs.size() - perm_gen_spec->misc_data_size()
duke@0 127 - perm_gen_spec->misc_code_size();
duke@0 128 _reserved.set_end((HeapWord*)(heap_rs.base() + actual_heap_size));
duke@0 129
duke@0 130 _rem_set = collector_policy()->create_rem_set(_reserved, n_covered_regions);
duke@0 131 set_barrier_set(rem_set()->bs());
duke@0 132 _gch = this;
duke@0 133
duke@0 134 for (i = 0; i < _n_gens; i++) {
duke@0 135 ReservedSpace this_rs = heap_rs.first_part(_gen_specs[i]->max_size(),
duke@0 136 UseSharedSpaces, UseSharedSpaces);
duke@0 137 _gens[i] = _gen_specs[i]->init(this_rs, i, rem_set());
duke@0 138 heap_rs = heap_rs.last_part(_gen_specs[i]->max_size());
duke@0 139 }
duke@0 140 _perm_gen = perm_gen_spec->init(heap_rs, PermSize, rem_set());
duke@0 141
duke@0 142 clear_incremental_collection_will_fail();
duke@0 143 clear_last_incremental_collection_failed();
duke@0 144
duke@0 145 #ifndef SERIALGC
duke@0 146 // If we are running CMS, create the collector responsible
duke@0 147 // for collecting the CMS generations.
duke@0 148 if (collector_policy()->is_concurrent_mark_sweep_policy()) {
duke@0 149 bool success = create_cms_collector();
duke@0 150 if (!success) return JNI_ENOMEM;
duke@0 151 }
duke@0 152 #endif // SERIALGC
duke@0 153
duke@0 154 return JNI_OK;
duke@0 155 }
duke@0 156
duke@0 157
duke@0 158 char* GenCollectedHeap::allocate(size_t alignment,
duke@0 159 PermanentGenerationSpec* perm_gen_spec,
duke@0 160 size_t* _total_reserved,
duke@0 161 int* _n_covered_regions,
duke@0 162 ReservedSpace* heap_rs){
duke@0 163 const char overflow_msg[] = "The size of the object heap + VM data exceeds "
duke@0 164 "the maximum representable size";
duke@0 165
duke@0 166 // Now figure out the total size.
duke@0 167 size_t total_reserved = 0;
duke@0 168 int n_covered_regions = 0;
duke@0 169 const size_t pageSize = UseLargePages ?
duke@0 170 os::large_page_size() : os::vm_page_size();
duke@0 171
duke@0 172 for (int i = 0; i < _n_gens; i++) {
duke@0 173 total_reserved += _gen_specs[i]->max_size();
duke@0 174 if (total_reserved < _gen_specs[i]->max_size()) {
duke@0 175 vm_exit_during_initialization(overflow_msg);
duke@0 176 }
duke@0 177 n_covered_regions += _gen_specs[i]->n_covered_regions();
duke@0 178 }
duke@0 179 assert(total_reserved % pageSize == 0, "Gen size");
duke@0 180 total_reserved += perm_gen_spec->max_size();
duke@0 181 assert(total_reserved % pageSize == 0, "Perm Gen size");
duke@0 182
duke@0 183 if (total_reserved < perm_gen_spec->max_size()) {
duke@0 184 vm_exit_during_initialization(overflow_msg);
duke@0 185 }
duke@0 186 n_covered_regions += perm_gen_spec->n_covered_regions();
duke@0 187
duke@0 188 // Add the size of the data area which shares the same reserved area
duke@0 189 // as the heap, but which is not actually part of the heap.
duke@0 190 size_t s = perm_gen_spec->misc_data_size() + perm_gen_spec->misc_code_size();
duke@0 191
duke@0 192 total_reserved += s;
duke@0 193 if (total_reserved < s) {
duke@0 194 vm_exit_during_initialization(overflow_msg);
duke@0 195 }
duke@0 196
duke@0 197 if (UseLargePages) {
duke@0 198 assert(total_reserved != 0, "total_reserved cannot be 0");
duke@0 199 total_reserved = round_to(total_reserved, os::large_page_size());
duke@0 200 if (total_reserved < os::large_page_size()) {
duke@0 201 vm_exit_during_initialization(overflow_msg);
duke@0 202 }
duke@0 203 }
duke@0 204
duke@0 205 // Calculate the address at which the heap must reside in order for
duke@0 206 // the shared data to be at the required address.
duke@0 207
duke@0 208 char* heap_address;
duke@0 209 if (UseSharedSpaces) {
duke@0 210
duke@0 211 // Calculate the address of the first word beyond the heap.
duke@0 212 FileMapInfo* mapinfo = FileMapInfo::current_info();
duke@0 213 int lr = CompactingPermGenGen::n_regions - 1;
duke@0 214 size_t capacity = align_size_up(mapinfo->space_capacity(lr), alignment);
duke@0 215 heap_address = mapinfo->region_base(lr) + capacity;
duke@0 216
duke@0 217 // Calculate the address of the first word of the heap.
duke@0 218 heap_address -= total_reserved;
duke@0 219 } else {
duke@0 220 heap_address = NULL; // any address will do.
duke@0 221 }
duke@0 222
duke@0 223 *_total_reserved = total_reserved;
duke@0 224 *_n_covered_regions = n_covered_regions;
duke@0 225 *heap_rs = ReservedSpace(total_reserved, alignment,
duke@0 226 UseLargePages, heap_address);
duke@0 227
duke@0 228 return heap_address;
duke@0 229 }
duke@0 230
duke@0 231
duke@0 232 void GenCollectedHeap::post_initialize() {
duke@0 233 SharedHeap::post_initialize();
duke@0 234 TwoGenerationCollectorPolicy *policy =
duke@0 235 (TwoGenerationCollectorPolicy *)collector_policy();
duke@0 236 guarantee(policy->is_two_generation_policy(), "Illegal policy type");
duke@0 237 DefNewGeneration* def_new_gen = (DefNewGeneration*) get_gen(0);
duke@0 238 assert(def_new_gen->kind() == Generation::DefNew ||
duke@0 239 def_new_gen->kind() == Generation::ParNew ||
duke@0 240 def_new_gen->kind() == Generation::ASParNew,
duke@0 241 "Wrong generation kind");
duke@0 242
duke@0 243 Generation* old_gen = get_gen(1);
duke@0 244 assert(old_gen->kind() == Generation::ConcurrentMarkSweep ||
duke@0 245 old_gen->kind() == Generation::ASConcurrentMarkSweep ||
duke@0 246 old_gen->kind() == Generation::MarkSweepCompact,
duke@0 247 "Wrong generation kind");
duke@0 248
duke@0 249 policy->initialize_size_policy(def_new_gen->eden()->capacity(),
duke@0 250 old_gen->capacity(),
duke@0 251 def_new_gen->from()->capacity());
duke@0 252 policy->initialize_gc_policy_counters();
duke@0 253 }
duke@0 254
duke@0 255 void GenCollectedHeap::ref_processing_init() {
duke@0 256 SharedHeap::ref_processing_init();
duke@0 257 for (int i = 0; i < _n_gens; i++) {
duke@0 258 _gens[i]->ref_processor_init();
duke@0 259 }
duke@0 260 }
duke@0 261
duke@0 262 size_t GenCollectedHeap::capacity() const {
duke@0 263 size_t res = 0;
duke@0 264 for (int i = 0; i < _n_gens; i++) {
duke@0 265 res += _gens[i]->capacity();
duke@0 266 }
duke@0 267 return res;
duke@0 268 }
duke@0 269
duke@0 270 size_t GenCollectedHeap::used() const {
duke@0 271 size_t res = 0;
duke@0 272 for (int i = 0; i < _n_gens; i++) {
duke@0 273 res += _gens[i]->used();
duke@0 274 }
duke@0 275 return res;
duke@0 276 }
duke@0 277
duke@0 278 // Save the "used_region" for generations level and lower,
duke@0 279 // and, if perm is true, for perm gen.
duke@0 280 void GenCollectedHeap::save_used_regions(int level, bool perm) {
duke@0 281 assert(level < _n_gens, "Illegal level parameter");
duke@0 282 for (int i = level; i >= 0; i--) {
duke@0 283 _gens[i]->save_used_region();
duke@0 284 }
duke@0 285 if (perm) {
duke@0 286 perm_gen()->save_used_region();
duke@0 287 }
duke@0 288 }
duke@0 289
duke@0 290 size_t GenCollectedHeap::max_capacity() const {
duke@0 291 size_t res = 0;
duke@0 292 for (int i = 0; i < _n_gens; i++) {
duke@0 293 res += _gens[i]->max_capacity();
duke@0 294 }
duke@0 295 return res;
duke@0 296 }
duke@0 297
duke@0 298 // Update the _full_collections_completed counter
duke@0 299 // at the end of a stop-world full GC.
duke@0 300 unsigned int GenCollectedHeap::update_full_collections_completed() {
duke@0 301 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
duke@0 302 assert(_full_collections_completed <= _total_full_collections,
duke@0 303 "Can't complete more collections than were started");
duke@0 304 _full_collections_completed = _total_full_collections;
duke@0 305 ml.notify_all();
duke@0 306 return _full_collections_completed;
duke@0 307 }
duke@0 308
duke@0 309 // Update the _full_collections_completed counter, as appropriate,
duke@0 310 // at the end of a concurrent GC cycle. Note the conditional update
duke@0 311 // below to allow this method to be called by a concurrent collector
duke@0 312 // without synchronizing in any manner with the VM thread (which
duke@0 313 // may already have initiated a STW full collection "concurrently").
duke@0 314 unsigned int GenCollectedHeap::update_full_collections_completed(unsigned int count) {
duke@0 315 MonitorLockerEx ml(FullGCCount_lock, Mutex::_no_safepoint_check_flag);
duke@0 316 assert((_full_collections_completed <= _total_full_collections) &&
duke@0 317 (count <= _total_full_collections),
duke@0 318 "Can't complete more collections than were started");
duke@0 319 if (count > _full_collections_completed) {
duke@0 320 _full_collections_completed = count;
duke@0 321 ml.notify_all();
duke@0 322 }
duke@0 323 return _full_collections_completed;
duke@0 324 }
duke@0 325
duke@0 326
duke@0 327 #ifndef PRODUCT
duke@0 328 // Override of memory state checking method in CollectedHeap:
duke@0 329 // Some collectors (CMS for example) can't have badHeapWordVal written
duke@0 330 // in the first two words of an object. (For instance , in the case of
duke@0 331 // CMS these words hold state used to synchronize between certain
duke@0 332 // (concurrent) GC steps and direct allocating mutators.)
duke@0 333 // The skip_header_HeapWords() method below, allows us to skip
duke@0 334 // over the requisite number of HeapWord's. Note that (for
duke@0 335 // generational collectors) this means that those many words are
duke@0 336 // skipped in each object, irrespective of the generation in which
duke@0 337 // that object lives. The resultant loss of precision seems to be
duke@0 338 // harmless and the pain of avoiding that imprecision appears somewhat
duke@0 339 // higher than we are prepared to pay for such rudimentary debugging
duke@0 340 // support.
duke@0 341 void GenCollectedHeap::check_for_non_bad_heap_word_value(HeapWord* addr,
duke@0 342 size_t size) {
duke@0 343 if (CheckMemoryInitialization && ZapUnusedHeapArea) {
duke@0 344 // We are asked to check a size in HeapWords,
duke@0 345 // but the memory is mangled in juint words.
duke@0 346 juint* start = (juint*) (addr + skip_header_HeapWords());
duke@0 347 juint* end = (juint*) (addr + size);
duke@0 348 for (juint* slot = start; slot < end; slot += 1) {
duke@0 349 assert(*slot == badHeapWordVal,
duke@0 350 "Found non badHeapWordValue in pre-allocation check");
duke@0 351 }
duke@0 352 }
duke@0 353 }
duke@0 354 #endif
duke@0 355
duke@0 356 HeapWord* GenCollectedHeap::attempt_allocation(size_t size,
duke@0 357 bool is_tlab,
duke@0 358 bool first_only) {
duke@0 359 HeapWord* res;
duke@0 360 for (int i = 0; i < _n_gens; i++) {
duke@0 361 if (_gens[i]->should_allocate(size, is_tlab)) {
duke@0 362 res = _gens[i]->allocate(size, is_tlab);
duke@0 363 if (res != NULL) return res;
duke@0 364 else if (first_only) break;
duke@0 365 }
duke@0 366 }
duke@0 367 // Otherwise...
duke@0 368 return NULL;
duke@0 369 }
duke@0 370
duke@0 371 HeapWord* GenCollectedHeap::mem_allocate(size_t size,
duke@0 372 bool is_large_noref,
duke@0 373 bool is_tlab,
duke@0 374 bool* gc_overhead_limit_was_exceeded) {
duke@0 375 return collector_policy()->mem_allocate_work(size,
duke@0 376 is_tlab,
duke@0 377 gc_overhead_limit_was_exceeded);
duke@0 378 }
duke@0 379
duke@0 380 bool GenCollectedHeap::must_clear_all_soft_refs() {
duke@0 381 return _gc_cause == GCCause::_last_ditch_collection;
duke@0 382 }
duke@0 383
duke@0 384 bool GenCollectedHeap::should_do_concurrent_full_gc(GCCause::Cause cause) {
duke@0 385 return (cause == GCCause::_java_lang_system_gc ||
duke@0 386 cause == GCCause::_gc_locker) &&
duke@0 387 UseConcMarkSweepGC && ExplicitGCInvokesConcurrent;
duke@0 388 }
duke@0 389
duke@0 390 void GenCollectedHeap::do_collection(bool full,
duke@0 391 bool clear_all_soft_refs,
duke@0 392 size_t size,
duke@0 393 bool is_tlab,
duke@0 394 int max_level) {
duke@0 395 bool prepared_for_verification = false;
duke@0 396 ResourceMark rm;
duke@0 397 DEBUG_ONLY(Thread* my_thread = Thread::current();)
duke@0 398
duke@0 399 assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint");
duke@0 400 assert(my_thread->is_VM_thread() ||
duke@0 401 my_thread->is_ConcurrentGC_thread(),
duke@0 402 "incorrect thread type capability");
duke@0 403 assert(Heap_lock->is_locked(), "the requesting thread should have the Heap_lock");
duke@0 404 guarantee(!is_gc_active(), "collection is not reentrant");
duke@0 405 assert(max_level < n_gens(), "sanity check");
duke@0 406
duke@0 407 if (GC_locker::check_active_before_gc()) {
duke@0 408 return; // GC is disabled (e.g. JNI GetXXXCritical operation)
duke@0 409 }
duke@0 410
duke@0 411 const size_t perm_prev_used = perm_gen()->used();
duke@0 412
duke@0 413 if (PrintHeapAtGC) {
duke@0 414 Universe::print_heap_before_gc();
duke@0 415 if (Verbose) {
duke@0 416 gclog_or_tty->print_cr("GC Cause: %s", GCCause::to_string(gc_cause()));
duke@0 417 }
duke@0 418 }
duke@0 419
duke@0 420 {
duke@0 421 FlagSetting fl(_is_gc_active, true);
duke@0 422
duke@0 423 bool complete = full && (max_level == (n_gens()-1));
duke@0 424 const char* gc_cause_str = "GC ";
duke@0 425 if (complete) {
duke@0 426 GCCause::Cause cause = gc_cause();
duke@0 427 if (cause == GCCause::_java_lang_system_gc) {
duke@0 428 gc_cause_str = "Full GC (System) ";
duke@0 429 } else {
duke@0 430 gc_cause_str = "Full GC ";
duke@0 431 }
duke@0 432 }
duke@0 433 gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps);
duke@0 434 TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty);
duke@0 435 TraceTime t(gc_cause_str, PrintGCDetails, false, gclog_or_tty);
duke@0 436
duke@0 437 gc_prologue(complete);
duke@0 438 increment_total_collections(complete);
duke@0 439
duke@0 440 size_t gch_prev_used = used();
duke@0 441
duke@0 442 int starting_level = 0;
duke@0 443 if (full) {
duke@0 444 // Search for the oldest generation which will collect all younger
duke@0 445 // generations, and start collection loop there.
duke@0 446 for (int i = max_level; i >= 0; i--) {
duke@0 447 if (_gens[i]->full_collects_younger_generations()) {
duke@0 448 starting_level = i;
duke@0 449 break;
duke@0 450 }
duke@0 451 }
duke@0 452 }
duke@0 453
duke@0 454 bool must_restore_marks_for_biased_locking = false;
duke@0 455
duke@0 456 int max_level_collected = starting_level;
duke@0 457 for (int i = starting_level; i <= max_level; i++) {
duke@0 458 if (_gens[i]->should_collect(full, size, is_tlab)) {
duke@0 459 // Timer for individual generations. Last argument is false: no CR
duke@0 460 TraceTime t1(_gens[i]->short_name(), PrintGCDetails, false, gclog_or_tty);
duke@0 461 TraceCollectorStats tcs(_gens[i]->counters());
duke@0 462 TraceMemoryManagerStats tmms(_gens[i]->kind());
duke@0 463
duke@0 464 size_t prev_used = _gens[i]->used();
duke@0 465 _gens[i]->stat_record()->invocations++;
duke@0 466 _gens[i]->stat_record()->accumulated_time.start();
duke@0 467
duke@0 468 if (PrintGC && Verbose) {
duke@0 469 gclog_or_tty->print("level=%d invoke=%d size=" SIZE_FORMAT,
duke@0 470 i,
duke@0 471 _gens[i]->stat_record()->invocations,
duke@0 472 size*HeapWordSize);
duke@0 473 }
duke@0 474
duke@0 475 if (VerifyBeforeGC && i >= VerifyGCLevel &&
duke@0 476 total_collections() >= VerifyGCStartAt) {
duke@0 477 HandleMark hm; // Discard invalid handles created during verification
duke@0 478 if (!prepared_for_verification) {
duke@0 479 prepare_for_verify();
duke@0 480 prepared_for_verification = true;
duke@0 481 }
duke@0 482 gclog_or_tty->print(" VerifyBeforeGC:");
duke@0 483 Universe::verify(true);
duke@0 484 }
duke@0 485 COMPILER2_PRESENT(DerivedPointerTable::clear());
duke@0 486
duke@0 487 if (!must_restore_marks_for_biased_locking &&
duke@0 488 _gens[i]->performs_in_place_marking()) {
duke@0 489 // We perform this mark word preservation work lazily
duke@0 490 // because it's only at this point that we know whether we
duke@0 491 // absolutely have to do it; we want to avoid doing it for
duke@0 492 // scavenge-only collections where it's unnecessary
duke@0 493 must_restore_marks_for_biased_locking = true;
duke@0 494 BiasedLocking::preserve_marks();
duke@0 495 }
duke@0 496
duke@0 497 // Do collection work
duke@0 498 {
duke@0 499 // Note on ref discovery: For what appear to be historical reasons,
duke@0 500 // GCH enables and disabled (by enqueing) refs discovery.
duke@0 501 // In the future this should be moved into the generation's
duke@0 502 // collect method so that ref discovery and enqueueing concerns
duke@0 503 // are local to a generation. The collect method could return
duke@0 504 // an appropriate indication in the case that notification on
duke@0 505 // the ref lock was needed. This will make the treatment of
duke@0 506 // weak refs more uniform (and indeed remove such concerns
duke@0 507 // from GCH). XXX
duke@0 508
duke@0 509 HandleMark hm; // Discard invalid handles created during gc
duke@0 510 save_marks(); // save marks for all gens
duke@0 511 // We want to discover references, but not process them yet.
duke@0 512 // This mode is disabled in process_discovered_references if the
duke@0 513 // generation does some collection work, or in
duke@0 514 // enqueue_discovered_references if the generation returns
duke@0 515 // without doing any work.
duke@0 516 ReferenceProcessor* rp = _gens[i]->ref_processor();
duke@0 517 // If the discovery of ("weak") refs in this generation is
duke@0 518 // atomic wrt other collectors in this configuration, we
duke@0 519 // are guaranteed to have empty discovered ref lists.
duke@0 520 if (rp->discovery_is_atomic()) {
duke@0 521 rp->verify_no_references_recorded();
duke@0 522 rp->enable_discovery();
duke@0 523 } else {
duke@0 524 // collect() will enable discovery as appropriate
duke@0 525 }
duke@0 526 _gens[i]->collect(full, clear_all_soft_refs, size, is_tlab);
duke@0 527 if (!rp->enqueuing_is_done()) {
duke@0 528 rp->enqueue_discovered_references();
duke@0 529 } else {
duke@0 530 rp->set_enqueuing_is_done(false);
duke@0 531 }
duke@0 532 rp->verify_no_references_recorded();
duke@0 533 }
duke@0 534 max_level_collected = i;
duke@0 535
duke@0 536 // Determine if allocation request was met.
duke@0 537 if (size > 0) {
duke@0 538 if (!is_tlab || _gens[i]->supports_tlab_allocation()) {
duke@0 539 if (size*HeapWordSize <= _gens[i]->unsafe_max_alloc_nogc()) {
duke@0 540 size = 0;
duke@0 541 }
duke@0 542 }
duke@0 543 }
duke@0 544
duke@0 545 COMPILER2_PRESENT(DerivedPointerTable::update_pointers());
duke@0 546
duke@0 547 _gens[i]->stat_record()->accumulated_time.stop();
duke@0 548
duke@0 549 update_gc_stats(i, full);
duke@0 550
duke@0 551 if (VerifyAfterGC && i >= VerifyGCLevel &&
duke@0 552 total_collections() >= VerifyGCStartAt) {
duke@0 553 HandleMark hm; // Discard invalid handles created during verification
duke@0 554 gclog_or_tty->print(" VerifyAfterGC:");
duke@0 555 Universe::verify(false);
duke@0 556 }
duke@0 557
duke@0 558 if (PrintGCDetails) {
duke@0 559 gclog_or_tty->print(":");
duke@0 560 _gens[i]->print_heap_change(prev_used);
duke@0 561 }
duke@0 562 }
duke@0 563 }
duke@0 564
duke@0 565 // Update "complete" boolean wrt what actually transpired --
duke@0 566 // for instance, a promotion failure could have led to
duke@0 567 // a whole heap collection.
duke@0 568 complete = complete || (max_level_collected == n_gens() - 1);
duke@0 569
duke@0 570 if (PrintGCDetails) {
duke@0 571 print_heap_change(gch_prev_used);
duke@0 572
duke@0 573 // Print perm gen info for full GC with PrintGCDetails flag.
duke@0 574 if (complete) {
duke@0 575 print_perm_heap_change(perm_prev_used);
duke@0 576 }
duke@0 577 }
duke@0 578
duke@0 579 for (int j = max_level_collected; j >= 0; j -= 1) {
duke@0 580 // Adjust generation sizes.
duke@0 581 _gens[j]->compute_new_size();
duke@0 582 }
duke@0 583
duke@0 584 if (complete) {
duke@0 585 // Ask the permanent generation to adjust size for full collections
duke@0 586 perm()->compute_new_size();
duke@0 587 update_full_collections_completed();
duke@0 588 }
duke@0 589
duke@0 590 // Track memory usage and detect low memory after GC finishes
duke@0 591 MemoryService::track_memory_usage();
duke@0 592
duke@0 593 gc_epilogue(complete);
duke@0 594
duke@0 595 if (must_restore_marks_for_biased_locking) {
duke@0 596 BiasedLocking::restore_marks();
duke@0 597 }
duke@0 598 }
duke@0 599
duke@0 600 AdaptiveSizePolicy* sp = gen_policy()->size_policy();
duke@0 601 AdaptiveSizePolicyOutput(sp, total_collections());
duke@0 602
duke@0 603 if (PrintHeapAtGC) {
duke@0 604 Universe::print_heap_after_gc();
duke@0 605 }
duke@0 606
duke@0 607 if (ExitAfterGCNum > 0 && total_collections() == ExitAfterGCNum) {
duke@0 608 tty->print_cr("Stopping after GC #%d", ExitAfterGCNum);
duke@0 609 vm_exit(-1);
duke@0 610 }
duke@0 611 }
duke@0 612
duke@0 613 HeapWord* GenCollectedHeap::satisfy_failed_allocation(size_t size, bool is_tlab) {
duke@0 614 return collector_policy()->satisfy_failed_allocation(size, is_tlab);
duke@0 615 }
duke@0 616
duke@0 617 void GenCollectedHeap::set_par_threads(int t) {
duke@0 618 SharedHeap::set_par_threads(t);
duke@0 619 _gen_process_strong_tasks->set_par_threads(t);
duke@0 620 }
duke@0 621
duke@0 622 class AssertIsPermClosure: public OopClosure {
duke@0 623 public:
duke@0 624 void do_oop(oop* p) {
duke@0 625 assert((*p) == NULL || (*p)->is_perm(), "Referent should be perm.");
duke@0 626 }
coleenp@113 627 void do_oop(narrowOop* p) { ShouldNotReachHere(); }
duke@0 628 };
duke@0 629 static AssertIsPermClosure assert_is_perm_closure;
duke@0 630
duke@0 631 void GenCollectedHeap::
duke@0 632 gen_process_strong_roots(int level,
duke@0 633 bool younger_gens_as_roots,
duke@0 634 bool collecting_perm_gen,
duke@0 635 SharedHeap::ScanningOption so,
duke@0 636 OopsInGenClosure* older_gens,
duke@0 637 OopsInGenClosure* not_older_gens) {
duke@0 638 // General strong roots.
duke@0 639 SharedHeap::process_strong_roots(collecting_perm_gen, so,
duke@0 640 not_older_gens, older_gens);
duke@0 641
duke@0 642 if (younger_gens_as_roots) {
duke@0 643 if (!_gen_process_strong_tasks->is_task_claimed(GCH_PS_younger_gens)) {
duke@0 644 for (int i = 0; i < level; i++) {
duke@0 645 not_older_gens->set_generation(_gens[i]);
duke@0 646 _gens[i]->oop_iterate(not_older_gens);
duke@0 647 }
duke@0 648 not_older_gens->reset_generation();
duke@0 649 }
duke@0 650 }
duke@0 651 // When collection is parallel, all threads get to cooperate to do
duke@0 652 // older-gen scanning.
duke@0 653 for (int i = level+1; i < _n_gens; i++) {
duke@0 654 older_gens->set_generation(_gens[i]);
duke@0 655 rem_set()->younger_refs_iterate(_gens[i], older_gens);
duke@0 656 older_gens->reset_generation();
duke@0 657 }
duke@0 658
duke@0 659 _gen_process_strong_tasks->all_tasks_completed();
duke@0 660 }
duke@0 661
duke@0 662 void GenCollectedHeap::gen_process_weak_roots(OopClosure* root_closure,
duke@0 663 OopClosure* non_root_closure) {
duke@0 664 SharedHeap::process_weak_roots(root_closure, non_root_closure);
duke@0 665 // "Local" "weak" refs
duke@0 666 for (int i = 0; i < _n_gens; i++) {
duke@0 667 _gens[i]->ref_processor()->weak_oops_do(root_closure);
duke@0 668 }
duke@0 669 }
duke@0 670
duke@0 671 #define GCH_SINCE_SAVE_MARKS_ITERATE_DEFN(OopClosureType, nv_suffix) \
duke@0 672 void GenCollectedHeap:: \
duke@0 673 oop_since_save_marks_iterate(int level, \
duke@0 674 OopClosureType* cur, \
duke@0 675 OopClosureType* older) { \
duke@0 676 _gens[level]->oop_since_save_marks_iterate##nv_suffix(cur); \
duke@0 677 for (int i = level+1; i < n_gens(); i++) { \
duke@0 678 _gens[i]->oop_since_save_marks_iterate##nv_suffix(older); \
duke@0 679 } \
duke@0 680 perm_gen()->oop_since_save_marks_iterate##nv_suffix(older); \
duke@0 681 }
duke@0 682
duke@0 683 ALL_SINCE_SAVE_MARKS_CLOSURES(GCH_SINCE_SAVE_MARKS_ITERATE_DEFN)
duke@0 684
duke@0 685 #undef GCH_SINCE_SAVE_MARKS_ITERATE_DEFN
duke@0 686
duke@0 687 bool GenCollectedHeap::no_allocs_since_save_marks(int level) {
duke@0 688 for (int i = level; i < _n_gens; i++) {
duke@0 689 if (!_gens[i]->no_allocs_since_save_marks()) return false;
duke@0 690 }
duke@0 691 return perm_gen()->no_allocs_since_save_marks();
duke@0 692 }
duke@0 693
duke@0 694 bool GenCollectedHeap::supports_inline_contig_alloc() const {
duke@0 695 return _gens[0]->supports_inline_contig_alloc();
duke@0 696 }
duke@0 697
duke@0 698 HeapWord** GenCollectedHeap::top_addr() const {
duke@0 699 return _gens[0]->top_addr();
duke@0 700 }
duke@0 701
duke@0 702 HeapWord** GenCollectedHeap::end_addr() const {
duke@0 703 return _gens[0]->end_addr();
duke@0 704 }
duke@0 705
duke@0 706 size_t GenCollectedHeap::unsafe_max_alloc() {
duke@0 707 return _gens[0]->unsafe_max_alloc_nogc();
duke@0 708 }
duke@0 709
duke@0 710 // public collection interfaces
duke@0 711
duke@0 712 void GenCollectedHeap::collect(GCCause::Cause cause) {
duke@0 713 if (should_do_concurrent_full_gc(cause)) {
duke@0 714 #ifndef SERIALGC
duke@0 715 // mostly concurrent full collection
duke@0 716 collect_mostly_concurrent(cause);
duke@0 717 #else // SERIALGC
duke@0 718 ShouldNotReachHere();
duke@0 719 #endif // SERIALGC
duke@0 720 } else {
duke@0 721 #ifdef ASSERT
duke@0 722 if (cause == GCCause::_scavenge_alot) {
duke@0 723 // minor collection only
duke@0 724 collect(cause, 0);
duke@0 725 } else {
duke@0 726 // Stop-the-world full collection
duke@0 727 collect(cause, n_gens() - 1);
duke@0 728 }
duke@0 729 #else
duke@0 730 // Stop-the-world full collection
duke@0 731 collect(cause, n_gens() - 1);
duke@0 732 #endif
duke@0 733 }
duke@0 734 }
duke@0 735
duke@0 736 void GenCollectedHeap::collect(GCCause::Cause cause, int max_level) {
duke@0 737 // The caller doesn't have the Heap_lock
duke@0 738 assert(!Heap_lock->owned_by_self(), "this thread should not own the Heap_lock");
duke@0 739 MutexLocker ml(Heap_lock);
duke@0 740 collect_locked(cause, max_level);
duke@0 741 }
duke@0 742
duke@0 743 // This interface assumes that it's being called by the
duke@0 744 // vm thread. It collects the heap assuming that the
duke@0 745 // heap lock is already held and that we are executing in
duke@0 746 // the context of the vm thread.
duke@0 747 void GenCollectedHeap::collect_as_vm_thread(GCCause::Cause cause) {
duke@0 748 assert(Thread::current()->is_VM_thread(), "Precondition#1");
duke@0 749 assert(Heap_lock->is_locked(), "Precondition#2");
duke@0 750 GCCauseSetter gcs(this, cause);
duke@0 751 switch (cause) {
duke@0 752 case GCCause::_heap_inspection:
duke@0 753 case GCCause::_heap_dump: {
duke@0 754 HandleMark hm;
duke@0 755 do_full_collection(false, // don't clear all soft refs
duke@0 756 n_gens() - 1);
duke@0 757 break;
duke@0 758 }
duke@0 759 default: // XXX FIX ME
duke@0 760 ShouldNotReachHere(); // Unexpected use of this function
duke@0 761 }
duke@0 762 }
duke@0 763
duke@0 764 void GenCollectedHeap::collect_locked(GCCause::Cause cause) {
duke@0 765 // The caller has the Heap_lock
duke@0 766 assert(Heap_lock->owned_by_self(), "this thread should own the Heap_lock");
duke@0 767 collect_locked(cause, n_gens() - 1);
duke@0 768 }
duke@0 769
duke@0 770 // this is the private collection interface
duke@0 771 // The Heap_lock is expected to be held on entry.
duke@0 772
duke@0 773 void GenCollectedHeap::collect_locked(GCCause::Cause cause, int max_level) {
duke@0 774 if (_preloading_shared_classes) {
duke@0 775 warning("\nThe permanent generation is not large enough to preload "
duke@0 776 "requested classes.\nUse -XX:PermSize= to increase the initial "
duke@0 777 "size of the permanent generation.\n");
duke@0 778 vm_exit(2);
duke@0 779 }
duke@0 780 // Read the GC count while holding the Heap_lock
duke@0 781 unsigned int gc_count_before = total_collections();
duke@0 782 unsigned int full_gc_count_before = total_full_collections();
duke@0 783 {
duke@0 784 MutexUnlocker mu(Heap_lock); // give up heap lock, execute gets it back
duke@0 785 VM_GenCollectFull op(gc_count_before, full_gc_count_before,
duke@0 786 cause, max_level);
duke@0 787 VMThread::execute(&op);
duke@0 788 }
duke@0 789 }
duke@0 790
duke@0 791 #ifndef SERIALGC
duke@0 792 bool GenCollectedHeap::create_cms_collector() {
duke@0 793
duke@0 794 assert(((_gens[1]->kind() == Generation::ConcurrentMarkSweep) ||
duke@0 795 (_gens[1]->kind() == Generation::ASConcurrentMarkSweep)) &&
duke@0 796 _perm_gen->as_gen()->kind() == Generation::ConcurrentMarkSweep,
duke@0 797 "Unexpected generation kinds");
duke@0 798 // Skip two header words in the block content verification
duke@0 799 NOT_PRODUCT(_skip_header_HeapWords = CMSCollector::skip_header_HeapWords();)
duke@0 800 CMSCollector* collector = new CMSCollector(
duke@0 801 (ConcurrentMarkSweepGeneration*)_gens[1],
duke@0 802 (ConcurrentMarkSweepGeneration*)_perm_gen->as_gen(),
duke@0 803 _rem_set->as_CardTableRS(),
duke@0 804 (ConcurrentMarkSweepPolicy*) collector_policy());
duke@0 805
duke@0 806 if (collector == NULL || !collector->completed_initialization()) {
duke@0 807 if (collector) {
duke@0 808 delete collector; // Be nice in embedded situation
duke@0 809 }
duke@0 810 vm_shutdown_during_initialization("Could not create CMS collector");
duke@0 811 return false;
duke@0 812 }
duke@0 813 return true; // success
duke@0 814 }
duke@0 815
duke@0 816 void GenCollectedHeap::collect_mostly_concurrent(GCCause::Cause cause) {
duke@0 817 assert(!Heap_lock->owned_by_self(), "Should not own Heap_lock");
duke@0 818
duke@0 819 MutexLocker ml(Heap_lock);
duke@0 820 // Read the GC counts while holding the Heap_lock
duke@0 821 unsigned int full_gc_count_before = total_full_collections();
duke@0 822 unsigned int gc_count_before = total_collections();
duke@0 823 {
duke@0 824 MutexUnlocker mu(Heap_lock);
duke@0 825 VM_GenCollectFullConcurrent op(gc_count_before, full_gc_count_before, cause);
duke@0 826 VMThread::execute(&op);
duke@0 827 }
duke@0 828 }
duke@0 829 #endif // SERIALGC
duke@0 830
duke@0 831
duke@0 832 void GenCollectedHeap::do_full_collection(bool clear_all_soft_refs,
duke@0 833 int max_level) {
duke@0 834 int local_max_level;
duke@0 835 if (!incremental_collection_will_fail() &&
duke@0 836 gc_cause() == GCCause::_gc_locker) {
duke@0 837 local_max_level = 0;
duke@0 838 } else {
duke@0 839 local_max_level = max_level;
duke@0 840 }
duke@0 841
duke@0 842 do_collection(true /* full */,
duke@0 843 clear_all_soft_refs /* clear_all_soft_refs */,
duke@0 844 0 /* size */,
duke@0 845 false /* is_tlab */,
duke@0 846 local_max_level /* max_level */);
duke@0 847 // Hack XXX FIX ME !!!
duke@0 848 // A scavenge may not have been attempted, or may have
duke@0 849 // been attempted and failed, because the old gen was too full
duke@0 850 if (local_max_level == 0 && gc_cause() == GCCause::_gc_locker &&
duke@0 851 incremental_collection_will_fail()) {
duke@0 852 if (PrintGCDetails) {
duke@0 853 gclog_or_tty->print_cr("GC locker: Trying a full collection "
duke@0 854 "because scavenge failed");
duke@0 855 }
duke@0 856 // This time allow the old gen to be collected as well
duke@0 857 do_collection(true /* full */,
duke@0 858 clear_all_soft_refs /* clear_all_soft_refs */,
duke@0 859 0 /* size */,
duke@0 860 false /* is_tlab */,
duke@0 861 n_gens() - 1 /* max_level */);
duke@0 862 }
duke@0 863 }
duke@0 864
duke@0 865 // Returns "TRUE" iff "p" points into the allocated area of the heap.
duke@0 866 bool GenCollectedHeap::is_in(const void* p) const {
duke@0 867 #ifndef ASSERT
duke@0 868 guarantee(VerifyBeforeGC ||
duke@0 869 VerifyDuringGC ||
duke@0 870 VerifyBeforeExit ||
duke@0 871 VerifyAfterGC, "too expensive");
duke@0 872 #endif
duke@0 873 // This might be sped up with a cache of the last generation that
duke@0 874 // answered yes.
duke@0 875 for (int i = 0; i < _n_gens; i++) {
duke@0 876 if (_gens[i]->is_in(p)) return true;
duke@0 877 }
duke@0 878 if (_perm_gen->as_gen()->is_in(p)) return true;
duke@0 879 // Otherwise...
duke@0 880 return false;
duke@0 881 }
duke@0 882
duke@0 883 // Returns "TRUE" iff "p" points into the allocated area of the heap.
duke@0 884 bool GenCollectedHeap::is_in_youngest(void* p) {
duke@0 885 return _gens[0]->is_in(p);
duke@0 886 }
duke@0 887
duke@0 888 void GenCollectedHeap::oop_iterate(OopClosure* cl) {
duke@0 889 for (int i = 0; i < _n_gens; i++) {
duke@0 890 _gens[i]->oop_iterate(cl);
duke@0 891 }
duke@0 892 }
duke@0 893
duke@0 894 void GenCollectedHeap::oop_iterate(MemRegion mr, OopClosure* cl) {
duke@0 895 for (int i = 0; i < _n_gens; i++) {
duke@0 896 _gens[i]->oop_iterate(mr, cl);
duke@0 897 }
duke@0 898 }
duke@0 899
duke@0 900 void GenCollectedHeap::object_iterate(ObjectClosure* cl) {
duke@0 901 for (int i = 0; i < _n_gens; i++) {
duke@0 902 _gens[i]->object_iterate(cl);
duke@0 903 }
duke@0 904 perm_gen()->object_iterate(cl);
duke@0 905 }
duke@0 906
duke@0 907 void GenCollectedHeap::object_iterate_since_last_GC(ObjectClosure* cl) {
duke@0 908 for (int i = 0; i < _n_gens; i++) {
duke@0 909 _gens[i]->object_iterate_since_last_GC(cl);
duke@0 910 }
duke@0 911 }
duke@0 912
duke@0 913 Space* GenCollectedHeap::space_containing(const void* addr) const {
duke@0 914 for (int i = 0; i < _n_gens; i++) {
duke@0 915 Space* res = _gens[i]->space_containing(addr);
duke@0 916 if (res != NULL) return res;
duke@0 917 }
duke@0 918 Space* res = perm_gen()->space_containing(addr);
duke@0 919 if (res != NULL) return res;
duke@0 920 // Otherwise...
duke@0 921 assert(false, "Could not find containing space");
duke@0 922 return NULL;
duke@0 923 }
duke@0 924
duke@0 925
duke@0 926 HeapWord* GenCollectedHeap::block_start(const void* addr) const {
duke@0 927 assert(is_in_reserved(addr), "block_start of address outside of heap");
duke@0 928 for (int i = 0; i < _n_gens; i++) {
duke@0 929 if (_gens[i]->is_in_reserved(addr)) {
duke@0 930 assert(_gens[i]->is_in(addr),
duke@0 931 "addr should be in allocated part of generation");
duke@0 932 return _gens[i]->block_start(addr);
duke@0 933 }
duke@0 934 }
duke@0 935 if (perm_gen()->is_in_reserved(addr)) {
duke@0 936 assert(perm_gen()->is_in(addr),
duke@0 937 "addr should be in allocated part of perm gen");
duke@0 938 return perm_gen()->block_start(addr);
duke@0 939 }
duke@0 940 assert(false, "Some generation should contain the address");
duke@0 941 return NULL;
duke@0 942 }
duke@0 943
duke@0 944 size_t GenCollectedHeap::block_size(const HeapWord* addr) const {
duke@0 945 assert(is_in_reserved(addr), "block_size of address outside of heap");
duke@0 946 for (int i = 0; i < _n_gens; i++) {
duke@0 947 if (_gens[i]->is_in_reserved(addr)) {
duke@0 948 assert(_gens[i]->is_in(addr),
duke@0 949 "addr should be in allocated part of generation");
duke@0 950 return _gens[i]->block_size(addr);
duke@0 951 }
duke@0 952 }
duke@0 953 if (perm_gen()->is_in_reserved(addr)) {
duke@0 954 assert(perm_gen()->is_in(addr),
duke@0 955 "addr should be in allocated part of perm gen");
duke@0 956 return perm_gen()->block_size(addr);
duke@0 957 }
duke@0 958 assert(false, "Some generation should contain the address");
duke@0 959 return 0;
duke@0 960 }
duke@0 961
duke@0 962 bool GenCollectedHeap::block_is_obj(const HeapWord* addr) const {
duke@0 963 assert(is_in_reserved(addr), "block_is_obj of address outside of heap");
duke@0 964 assert(block_start(addr) == addr, "addr must be a block start");
duke@0 965 for (int i = 0; i < _n_gens; i++) {
duke@0 966 if (_gens[i]->is_in_reserved(addr)) {
duke@0 967 return _gens[i]->block_is_obj(addr);
duke@0 968 }
duke@0 969 }
duke@0 970 if (perm_gen()->is_in_reserved(addr)) {
duke@0 971 return perm_gen()->block_is_obj(addr);
duke@0 972 }
duke@0 973 assert(false, "Some generation should contain the address");
duke@0 974 return false;
duke@0 975 }
duke@0 976
duke@0 977 bool GenCollectedHeap::supports_tlab_allocation() const {
duke@0 978 for (int i = 0; i < _n_gens; i += 1) {
duke@0 979 if (_gens[i]->supports_tlab_allocation()) {
duke@0 980 return true;
duke@0 981 }
duke@0 982 }
duke@0 983 return false;
duke@0 984 }
duke@0 985
duke@0 986 size_t GenCollectedHeap::tlab_capacity(Thread* thr) const {
duke@0 987 size_t result = 0;
duke@0 988 for (int i = 0; i < _n_gens; i += 1) {
duke@0 989 if (_gens[i]->supports_tlab_allocation()) {
duke@0 990 result += _gens[i]->tlab_capacity();
duke@0 991 }
duke@0 992 }
duke@0 993 return result;
duke@0 994 }
duke@0 995
duke@0 996 size_t GenCollectedHeap::unsafe_max_tlab_alloc(Thread* thr) const {
duke@0 997 size_t result = 0;
duke@0 998 for (int i = 0; i < _n_gens; i += 1) {
duke@0 999 if (_gens[i]->supports_tlab_allocation()) {
duke@0 1000 result += _gens[i]->unsafe_max_tlab_alloc();
duke@0 1001 }
duke@0 1002 }
duke@0 1003 return result;
duke@0 1004 }
duke@0 1005
duke@0 1006 HeapWord* GenCollectedHeap::allocate_new_tlab(size_t size) {
duke@0 1007 bool gc_overhead_limit_was_exceeded;
duke@0 1008 HeapWord* result = mem_allocate(size /* size */,
duke@0 1009 false /* is_large_noref */,
duke@0 1010 true /* is_tlab */,
duke@0 1011 &gc_overhead_limit_was_exceeded);
duke@0 1012 return result;
duke@0 1013 }
duke@0 1014
duke@0 1015 // Requires "*prev_ptr" to be non-NULL. Deletes and a block of minimal size
duke@0 1016 // from the list headed by "*prev_ptr".
duke@0 1017 static ScratchBlock *removeSmallestScratch(ScratchBlock **prev_ptr) {
duke@0 1018 bool first = true;
duke@0 1019 size_t min_size = 0; // "first" makes this conceptually infinite.
duke@0 1020 ScratchBlock **smallest_ptr, *smallest;
duke@0 1021 ScratchBlock *cur = *prev_ptr;
duke@0 1022 while (cur) {
duke@0 1023 assert(*prev_ptr == cur, "just checking");
duke@0 1024 if (first || cur->num_words < min_size) {
duke@0 1025 smallest_ptr = prev_ptr;
duke@0 1026 smallest = cur;
duke@0 1027 min_size = smallest->num_words;
duke@0 1028 first = false;
duke@0 1029 }
duke@0 1030 prev_ptr = &cur->next;
duke@0 1031 cur = cur->next;
duke@0 1032 }
duke@0 1033 smallest = *smallest_ptr;
duke@0 1034 *smallest_ptr = smallest->next;
duke@0 1035 return smallest;
duke@0 1036 }
duke@0 1037
duke@0 1038 // Sort the scratch block list headed by res into decreasing size order,
duke@0 1039 // and set "res" to the result.
duke@0 1040 static void sort_scratch_list(ScratchBlock*& list) {
duke@0 1041 ScratchBlock* sorted = NULL;
duke@0 1042 ScratchBlock* unsorted = list;
duke@0 1043 while (unsorted) {
duke@0 1044 ScratchBlock *smallest = removeSmallestScratch(&unsorted);
duke@0 1045 smallest->next = sorted;
duke@0 1046 sorted = smallest;
duke@0 1047 }
duke@0 1048 list = sorted;
duke@0 1049 }
duke@0 1050
duke@0 1051 ScratchBlock* GenCollectedHeap::gather_scratch(Generation* requestor,
duke@0 1052 size_t max_alloc_words) {
duke@0 1053 ScratchBlock* res = NULL;
duke@0 1054 for (int i = 0; i < _n_gens; i++) {
duke@0 1055 _gens[i]->contribute_scratch(res, requestor, max_alloc_words);
duke@0 1056 }
duke@0 1057 sort_scratch_list(res);
duke@0 1058 return res;
duke@0 1059 }
duke@0 1060
duke@0 1061 size_t GenCollectedHeap::large_typearray_limit() {
duke@0 1062 return gen_policy()->large_typearray_limit();
duke@0 1063 }
duke@0 1064
duke@0 1065 class GenPrepareForVerifyClosure: public GenCollectedHeap::GenClosure {
duke@0 1066 void do_generation(Generation* gen) {
duke@0 1067 gen->prepare_for_verify();
duke@0 1068 }
duke@0 1069 };
duke@0 1070
duke@0 1071 void GenCollectedHeap::prepare_for_verify() {
duke@0 1072 ensure_parsability(false); // no need to retire TLABs
duke@0 1073 GenPrepareForVerifyClosure blk;
duke@0 1074 generation_iterate(&blk, false);
duke@0 1075 perm_gen()->prepare_for_verify();
duke@0 1076 }
duke@0 1077
duke@0 1078
duke@0 1079 void GenCollectedHeap::generation_iterate(GenClosure* cl,
duke@0 1080 bool old_to_young) {
duke@0 1081 if (old_to_young) {
duke@0 1082 for (int i = _n_gens-1; i >= 0; i--) {
duke@0 1083 cl->do_generation(_gens[i]);
duke@0 1084 }
duke@0 1085 } else {
duke@0 1086 for (int i = 0; i < _n_gens; i++) {
duke@0 1087 cl->do_generation(_gens[i]);
duke@0 1088 }
duke@0 1089 }
duke@0 1090 }
duke@0 1091
duke@0 1092 void GenCollectedHeap::space_iterate(SpaceClosure* cl) {
duke@0 1093 for (int i = 0; i < _n_gens; i++) {
duke@0 1094 _gens[i]->space_iterate(cl, true);
duke@0 1095 }
duke@0 1096 perm_gen()->space_iterate(cl, true);
duke@0 1097 }
duke@0 1098
duke@0 1099 bool GenCollectedHeap::is_maximal_no_gc() const {
duke@0 1100 for (int i = 0; i < _n_gens; i++) { // skip perm gen
duke@0 1101 if (!_gens[i]->is_maximal_no_gc()) {
duke@0 1102 return false;
duke@0 1103 }
duke@0 1104 }
duke@0 1105 return true;
duke@0 1106 }
duke@0 1107
duke@0 1108 void GenCollectedHeap::save_marks() {
duke@0 1109 for (int i = 0; i < _n_gens; i++) {
duke@0 1110 _gens[i]->save_marks();
duke@0 1111 }
duke@0 1112 perm_gen()->save_marks();
duke@0 1113 }
duke@0 1114
duke@0 1115 void GenCollectedHeap::compute_new_generation_sizes(int collectedGen) {
duke@0 1116 for (int i = 0; i <= collectedGen; i++) {
duke@0 1117 _gens[i]->compute_new_size();
duke@0 1118 }
duke@0 1119 }
duke@0 1120
duke@0 1121 GenCollectedHeap* GenCollectedHeap::heap() {
duke@0 1122 assert(_gch != NULL, "Uninitialized access to GenCollectedHeap::heap()");
duke@0 1123 assert(_gch->kind() == CollectedHeap::GenCollectedHeap, "not a generational heap");
duke@0 1124 return _gch;
duke@0 1125 }
duke@0 1126
duke@0 1127
duke@0 1128 void GenCollectedHeap::prepare_for_compaction() {
duke@0 1129 Generation* scanning_gen = _gens[_n_gens-1];
duke@0 1130 // Start by compacting into same gen.
duke@0 1131 CompactPoint cp(scanning_gen, NULL, NULL);
duke@0 1132 while (scanning_gen != NULL) {
duke@0 1133 scanning_gen->prepare_for_compaction(&cp);
duke@0 1134 scanning_gen = prev_gen(scanning_gen);
duke@0 1135 }
duke@0 1136 }
duke@0 1137
duke@0 1138 GCStats* GenCollectedHeap::gc_stats(int level) const {
duke@0 1139 return _gens[level]->gc_stats();
duke@0 1140 }
duke@0 1141
duke@0 1142 void GenCollectedHeap::verify(bool allow_dirty, bool silent) {
duke@0 1143 if (!silent) {
duke@0 1144 gclog_or_tty->print("permgen ");
duke@0 1145 }
duke@0 1146 perm_gen()->verify(allow_dirty);
duke@0 1147 for (int i = _n_gens-1; i >= 0; i--) {
duke@0 1148 Generation* g = _gens[i];
duke@0 1149 if (!silent) {
duke@0 1150 gclog_or_tty->print(g->name());
duke@0 1151 gclog_or_tty->print(" ");
duke@0 1152 }
duke@0 1153 g->verify(allow_dirty);
duke@0 1154 }
duke@0 1155 if (!silent) {
duke@0 1156 gclog_or_tty->print("remset ");
duke@0 1157 }
duke@0 1158 rem_set()->verify();
duke@0 1159 if (!silent) {
duke@0 1160 gclog_or_tty->print("ref_proc ");
duke@0 1161 }
duke@0 1162 ReferenceProcessor::verify();
duke@0 1163 }
duke@0 1164
duke@0 1165 void GenCollectedHeap::print() const { print_on(tty); }
duke@0 1166 void GenCollectedHeap::print_on(outputStream* st) const {
duke@0 1167 for (int i = 0; i < _n_gens; i++) {
duke@0 1168 _gens[i]->print_on(st);
duke@0 1169 }
duke@0 1170 perm_gen()->print_on(st);
duke@0 1171 }
duke@0 1172
duke@0 1173 void GenCollectedHeap::gc_threads_do(ThreadClosure* tc) const {
duke@0 1174 if (workers() != NULL) {
duke@0 1175 workers()->threads_do(tc);
duke@0 1176 }
duke@0 1177 #ifndef SERIALGC
duke@0 1178 if (UseConcMarkSweepGC) {
duke@0 1179 ConcurrentMarkSweepThread::threads_do(tc);
duke@0 1180 }
duke@0 1181 #endif // SERIALGC
duke@0 1182 }
duke@0 1183
duke@0 1184 void GenCollectedHeap::print_gc_threads_on(outputStream* st) const {
duke@0 1185 #ifndef SERIALGC
duke@0 1186 if (UseParNewGC) {
duke@0 1187 workers()->print_worker_threads_on(st);
duke@0 1188 }
duke@0 1189 if (UseConcMarkSweepGC) {
duke@0 1190 ConcurrentMarkSweepThread::print_all_on(st);
duke@0 1191 }
duke@0 1192 #endif // SERIALGC
duke@0 1193 }
duke@0 1194
duke@0 1195 void GenCollectedHeap::print_tracing_info() const {
duke@0 1196 if (TraceGen0Time) {
duke@0 1197 get_gen(0)->print_summary_info();
duke@0 1198 }
duke@0 1199 if (TraceGen1Time) {
duke@0 1200 get_gen(1)->print_summary_info();
duke@0 1201 }
duke@0 1202 }
duke@0 1203
duke@0 1204 void GenCollectedHeap::print_heap_change(size_t prev_used) const {
duke@0 1205 if (PrintGCDetails && Verbose) {
duke@0 1206 gclog_or_tty->print(" " SIZE_FORMAT
duke@0 1207 "->" SIZE_FORMAT
duke@0 1208 "(" SIZE_FORMAT ")",
duke@0 1209 prev_used, used(), capacity());
duke@0 1210 } else {
duke@0 1211 gclog_or_tty->print(" " SIZE_FORMAT "K"
duke@0 1212 "->" SIZE_FORMAT "K"
duke@0 1213 "(" SIZE_FORMAT "K)",
duke@0 1214 prev_used / K, used() / K, capacity() / K);
duke@0 1215 }
duke@0 1216 }
duke@0 1217
duke@0 1218 //New method to print perm gen info with PrintGCDetails flag
duke@0 1219 void GenCollectedHeap::print_perm_heap_change(size_t perm_prev_used) const {
duke@0 1220 gclog_or_tty->print(", [%s :", perm_gen()->short_name());
duke@0 1221 perm_gen()->print_heap_change(perm_prev_used);
duke@0 1222 gclog_or_tty->print("]");
duke@0 1223 }
duke@0 1224
duke@0 1225 class GenGCPrologueClosure: public GenCollectedHeap::GenClosure {
duke@0 1226 private:
duke@0 1227 bool _full;
duke@0 1228 public:
duke@0 1229 void do_generation(Generation* gen) {
duke@0 1230 gen->gc_prologue(_full);
duke@0 1231 }
duke@0 1232 GenGCPrologueClosure(bool full) : _full(full) {};
duke@0 1233 };
duke@0 1234
duke@0 1235 void GenCollectedHeap::gc_prologue(bool full) {
duke@0 1236 assert(InlineCacheBuffer::is_empty(), "should have cleaned up ICBuffer");
duke@0 1237
duke@0 1238 always_do_update_barrier = false;
duke@0 1239 // Fill TLAB's and such
duke@0 1240 CollectedHeap::accumulate_statistics_all_tlabs();
duke@0 1241 ensure_parsability(true); // retire TLABs
duke@0 1242
duke@0 1243 // Call allocation profiler
duke@0 1244 AllocationProfiler::iterate_since_last_gc();
duke@0 1245 // Walk generations
duke@0 1246 GenGCPrologueClosure blk(full);
duke@0 1247 generation_iterate(&blk, false); // not old-to-young.
duke@0 1248 perm_gen()->gc_prologue(full);
duke@0 1249 };
duke@0 1250
duke@0 1251 class GenGCEpilogueClosure: public GenCollectedHeap::GenClosure {
duke@0 1252 private:
duke@0 1253 bool _full;
duke@0 1254 public:
duke@0 1255 void do_generation(Generation* gen) {
duke@0 1256 gen->gc_epilogue(_full);
duke@0 1257 }
duke@0 1258 GenGCEpilogueClosure(bool full) : _full(full) {};
duke@0 1259 };
duke@0 1260
duke@0 1261 void GenCollectedHeap::gc_epilogue(bool full) {
duke@0 1262 // Remember if a partial collection of the heap failed, and
duke@0 1263 // we did a complete collection.
duke@0 1264 if (full && incremental_collection_will_fail()) {
duke@0 1265 set_last_incremental_collection_failed();
duke@0 1266 } else {
duke@0 1267 clear_last_incremental_collection_failed();
duke@0 1268 }
duke@0 1269 // Clear the flag, if set; the generation gc_epilogues will set the
duke@0 1270 // flag again if the condition persists despite the collection.
duke@0 1271 clear_incremental_collection_will_fail();
duke@0 1272
duke@0 1273 #ifdef COMPILER2
duke@0 1274 assert(DerivedPointerTable::is_empty(), "derived pointer present");
duke@0 1275 size_t actual_gap = pointer_delta((HeapWord*) (max_uintx-3), *(end_addr()));
duke@0 1276 guarantee(actual_gap > (size_t)FastAllocateSizeLimit, "inline allocation wraps");
duke@0 1277 #endif /* COMPILER2 */
duke@0 1278
duke@0 1279 resize_all_tlabs();
duke@0 1280
duke@0 1281 GenGCEpilogueClosure blk(full);
duke@0 1282 generation_iterate(&blk, false); // not old-to-young.
duke@0 1283 perm_gen()->gc_epilogue(full);
duke@0 1284
duke@0 1285 always_do_update_barrier = UseConcMarkSweepGC;
duke@0 1286 };
duke@0 1287
duke@0 1288 class GenEnsureParsabilityClosure: public GenCollectedHeap::GenClosure {
duke@0 1289 public:
duke@0 1290 void do_generation(Generation* gen) {
duke@0 1291 gen->ensure_parsability();
duke@0 1292 }
duke@0 1293 };
duke@0 1294
duke@0 1295 void GenCollectedHeap::ensure_parsability(bool retire_tlabs) {
duke@0 1296 CollectedHeap::ensure_parsability(retire_tlabs);
duke@0 1297 GenEnsureParsabilityClosure ep_cl;
duke@0 1298 generation_iterate(&ep_cl, false);
duke@0 1299 perm_gen()->ensure_parsability();
duke@0 1300 }
duke@0 1301
duke@0 1302 oop GenCollectedHeap::handle_failed_promotion(Generation* gen,
duke@0 1303 oop obj,
coleenp@113 1304 size_t obj_size) {
duke@0 1305 assert(obj_size == (size_t)obj->size(), "bad obj_size passed in");
duke@0 1306 HeapWord* result = NULL;
duke@0 1307
duke@0 1308 // First give each higher generation a chance to allocate the promoted object.
duke@0 1309 Generation* allocator = next_gen(gen);
duke@0 1310 if (allocator != NULL) {
duke@0 1311 do {
duke@0 1312 result = allocator->allocate(obj_size, false);
duke@0 1313 } while (result == NULL && (allocator = next_gen(allocator)) != NULL);
duke@0 1314 }
duke@0 1315
duke@0 1316 if (result == NULL) {
duke@0 1317 // Then give gen and higher generations a chance to expand and allocate the
duke@0 1318 // object.
duke@0 1319 do {
duke@0 1320 result = gen->expand_and_allocate(obj_size, false);
duke@0 1321 } while (result == NULL && (gen = next_gen(gen)) != NULL);
duke@0 1322 }
duke@0 1323
duke@0 1324 if (result != NULL) {
duke@0 1325 Copy::aligned_disjoint_words((HeapWord*)obj, result, obj_size);
duke@0 1326 }
duke@0 1327 return oop(result);
duke@0 1328 }
duke@0 1329
duke@0 1330 class GenTimeOfLastGCClosure: public GenCollectedHeap::GenClosure {
duke@0 1331 jlong _time; // in ms
duke@0 1332 jlong _now; // in ms
duke@0 1333
duke@0 1334 public:
duke@0 1335 GenTimeOfLastGCClosure(jlong now) : _time(now), _now(now) { }
duke@0 1336
duke@0 1337 jlong time() { return _time; }
duke@0 1338
duke@0 1339 void do_generation(Generation* gen) {
duke@0 1340 _time = MIN2(_time, gen->time_of_last_gc(_now));
duke@0 1341 }
duke@0 1342 };
duke@0 1343
duke@0 1344 jlong GenCollectedHeap::millis_since_last_gc() {
duke@0 1345 jlong now = os::javaTimeMillis();
duke@0 1346 GenTimeOfLastGCClosure tolgc_cl(now);
duke@0 1347 // iterate over generations getting the oldest
duke@0 1348 // time that a generation was collected
duke@0 1349 generation_iterate(&tolgc_cl, false);
duke@0 1350 tolgc_cl.do_generation(perm_gen());
duke@0 1351 // XXX Despite the assert above, since javaTimeMillis()
duke@0 1352 // doesnot guarantee monotonically increasing return
duke@0 1353 // values (note, i didn't say "strictly monotonic"),
duke@0 1354 // we need to guard against getting back a time
duke@0 1355 // later than now. This should be fixed by basing
duke@0 1356 // on someting like gethrtime() which guarantees
duke@0 1357 // monotonicity. Note that cond_wait() is susceptible
duke@0 1358 // to a similar problem, because its interface is
duke@0 1359 // based on absolute time in the form of the
duke@0 1360 // system time's notion of UCT. See also 4506635
duke@0 1361 // for yet another problem of similar nature. XXX
duke@0 1362 jlong retVal = now - tolgc_cl.time();
duke@0 1363 if (retVal < 0) {
duke@0 1364 NOT_PRODUCT(warning("time warp: %d", retVal);)
duke@0 1365 return 0;
duke@0 1366 }
duke@0 1367 return retVal;
duke@0 1368 }