Thu, 11 Dec 2008 12:05:21 -0800
6765954: par compact - stress mode for splitting young gen spaces
Reviewed-by: jmasa
duke@435 | 1 | /* |
xdono@772 | 2 | * Copyright 2001-2008 Sun Microsystems, Inc. All Rights Reserved. |
duke@435 | 3 | * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
duke@435 | 4 | * |
duke@435 | 5 | * This code is free software; you can redistribute it and/or modify it |
duke@435 | 6 | * under the terms of the GNU General Public License version 2 only, as |
duke@435 | 7 | * published by the Free Software Foundation. |
duke@435 | 8 | * |
duke@435 | 9 | * This code is distributed in the hope that it will be useful, but WITHOUT |
duke@435 | 10 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
duke@435 | 11 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
duke@435 | 12 | * version 2 for more details (a copy is included in the LICENSE file that |
duke@435 | 13 | * accompanied this code). |
duke@435 | 14 | * |
duke@435 | 15 | * You should have received a copy of the GNU General Public License version |
duke@435 | 16 | * 2 along with this work; if not, write to the Free Software Foundation, |
duke@435 | 17 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
duke@435 | 18 | * |
duke@435 | 19 | * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara, |
duke@435 | 20 | * CA 95054 USA or visit www.sun.com if you need additional information or |
duke@435 | 21 | * have any questions. |
duke@435 | 22 | * |
duke@435 | 23 | */ |
duke@435 | 24 | |
duke@435 | 25 | #include "incls/_precompiled.incl" |
duke@435 | 26 | #include "incls/_psMarkSweep.cpp.incl" |
duke@435 | 27 | |
duke@435 | 28 | elapsedTimer PSMarkSweep::_accumulated_time; |
duke@435 | 29 | unsigned int PSMarkSweep::_total_invocations = 0; |
duke@435 | 30 | jlong PSMarkSweep::_time_of_last_gc = 0; |
duke@435 | 31 | CollectorCounters* PSMarkSweep::_counters = NULL; |
duke@435 | 32 | |
duke@435 | 33 | void PSMarkSweep::initialize() { |
duke@435 | 34 | MemRegion mr = Universe::heap()->reserved_region(); |
duke@435 | 35 | _ref_processor = new ReferenceProcessor(mr, |
duke@435 | 36 | true, // atomic_discovery |
duke@435 | 37 | false); // mt_discovery |
jcoomes@809 | 38 | _counters = new CollectorCounters("PSMarkSweep", 1); |
duke@435 | 39 | } |
duke@435 | 40 | |
duke@435 | 41 | // This method contains all heap specific policy for invoking mark sweep. |
duke@435 | 42 | // PSMarkSweep::invoke_no_policy() will only attempt to mark-sweep-compact |
duke@435 | 43 | // the heap. It will do nothing further. If we need to bail out for policy |
duke@435 | 44 | // reasons, scavenge before full gc, or any other specialized behavior, it |
duke@435 | 45 | // needs to be added here. |
duke@435 | 46 | // |
duke@435 | 47 | // Note that this method should only be called from the vm_thread while |
duke@435 | 48 | // at a safepoint! |
duke@435 | 49 | void PSMarkSweep::invoke(bool maximum_heap_compaction) { |
duke@435 | 50 | assert(SafepointSynchronize::is_at_safepoint(), "should be at safepoint"); |
duke@435 | 51 | assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread"); |
duke@435 | 52 | assert(!Universe::heap()->is_gc_active(), "not reentrant"); |
duke@435 | 53 | |
duke@435 | 54 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 55 | GCCause::Cause gc_cause = heap->gc_cause(); |
duke@435 | 56 | PSAdaptiveSizePolicy* policy = heap->size_policy(); |
duke@435 | 57 | |
duke@435 | 58 | // Before each allocation/collection attempt, find out from the |
duke@435 | 59 | // policy object if GCs are, on the whole, taking too long. If so, |
duke@435 | 60 | // bail out without attempting a collection. The exceptions are |
duke@435 | 61 | // for explicitly requested GC's. |
duke@435 | 62 | if (!policy->gc_time_limit_exceeded() || |
duke@435 | 63 | GCCause::is_user_requested_gc(gc_cause) || |
duke@435 | 64 | GCCause::is_serviceability_requested_gc(gc_cause)) { |
duke@435 | 65 | IsGCActiveMark mark; |
duke@435 | 66 | |
duke@435 | 67 | if (ScavengeBeforeFullGC) { |
duke@435 | 68 | PSScavenge::invoke_no_policy(); |
duke@435 | 69 | } |
duke@435 | 70 | |
duke@435 | 71 | int count = (maximum_heap_compaction)?1:MarkSweepAlwaysCompactCount; |
duke@435 | 72 | IntFlagSetting flag_setting(MarkSweepAlwaysCompactCount, count); |
duke@435 | 73 | PSMarkSweep::invoke_no_policy(maximum_heap_compaction); |
duke@435 | 74 | } |
duke@435 | 75 | } |
duke@435 | 76 | |
duke@435 | 77 | // This method contains no policy. You should probably |
duke@435 | 78 | // be calling invoke() instead. |
duke@435 | 79 | void PSMarkSweep::invoke_no_policy(bool clear_all_softrefs) { |
duke@435 | 80 | assert(SafepointSynchronize::is_at_safepoint(), "must be at a safepoint"); |
duke@435 | 81 | assert(ref_processor() != NULL, "Sanity"); |
duke@435 | 82 | |
duke@435 | 83 | if (GC_locker::check_active_before_gc()) { |
duke@435 | 84 | return; |
duke@435 | 85 | } |
duke@435 | 86 | |
duke@435 | 87 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 88 | GCCause::Cause gc_cause = heap->gc_cause(); |
duke@435 | 89 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 90 | PSAdaptiveSizePolicy* size_policy = heap->size_policy(); |
duke@435 | 91 | |
duke@435 | 92 | PSYoungGen* young_gen = heap->young_gen(); |
duke@435 | 93 | PSOldGen* old_gen = heap->old_gen(); |
duke@435 | 94 | PSPermGen* perm_gen = heap->perm_gen(); |
duke@435 | 95 | |
duke@435 | 96 | // Increment the invocation count |
duke@435 | 97 | heap->increment_total_collections(true /* full */); |
duke@435 | 98 | |
jmasa@698 | 99 | // Save information needed to minimize mangling |
jmasa@698 | 100 | heap->record_gen_tops_before_GC(); |
jmasa@698 | 101 | |
duke@435 | 102 | // We need to track unique mark sweep invocations as well. |
duke@435 | 103 | _total_invocations++; |
duke@435 | 104 | |
duke@435 | 105 | AdaptiveSizePolicyOutput(size_policy, heap->total_collections()); |
duke@435 | 106 | |
duke@435 | 107 | if (PrintHeapAtGC) { |
duke@435 | 108 | Universe::print_heap_before_gc(); |
duke@435 | 109 | } |
duke@435 | 110 | |
duke@435 | 111 | // Fill in TLABs |
duke@435 | 112 | heap->accumulate_statistics_all_tlabs(); |
duke@435 | 113 | heap->ensure_parsability(true); // retire TLABs |
duke@435 | 114 | |
duke@435 | 115 | if (VerifyBeforeGC && heap->total_collections() >= VerifyGCStartAt) { |
duke@435 | 116 | HandleMark hm; // Discard invalid handles created during verification |
duke@435 | 117 | gclog_or_tty->print(" VerifyBeforeGC:"); |
duke@435 | 118 | Universe::verify(true); |
duke@435 | 119 | } |
duke@435 | 120 | |
duke@435 | 121 | // Verify object start arrays |
duke@435 | 122 | if (VerifyObjectStartArray && |
duke@435 | 123 | VerifyBeforeGC) { |
duke@435 | 124 | old_gen->verify_object_start_array(); |
duke@435 | 125 | perm_gen->verify_object_start_array(); |
duke@435 | 126 | } |
duke@435 | 127 | |
duke@435 | 128 | // Filled in below to track the state of the young gen after the collection. |
duke@435 | 129 | bool eden_empty; |
duke@435 | 130 | bool survivors_empty; |
duke@435 | 131 | bool young_gen_empty; |
duke@435 | 132 | |
duke@435 | 133 | { |
duke@435 | 134 | HandleMark hm; |
duke@435 | 135 | const bool is_system_gc = gc_cause == GCCause::_java_lang_system_gc; |
duke@435 | 136 | // This is useful for debugging but don't change the output the |
duke@435 | 137 | // the customer sees. |
duke@435 | 138 | const char* gc_cause_str = "Full GC"; |
duke@435 | 139 | if (is_system_gc && PrintGCDetails) { |
duke@435 | 140 | gc_cause_str = "Full GC (System)"; |
duke@435 | 141 | } |
duke@435 | 142 | gclog_or_tty->date_stamp(PrintGC && PrintGCDateStamps); |
duke@435 | 143 | TraceCPUTime tcpu(PrintGCDetails, true, gclog_or_tty); |
duke@435 | 144 | TraceTime t1(gc_cause_str, PrintGC, !PrintGCDetails, gclog_or_tty); |
duke@435 | 145 | TraceCollectorStats tcs(counters()); |
duke@435 | 146 | TraceMemoryManagerStats tms(true /* Full GC */); |
duke@435 | 147 | |
duke@435 | 148 | if (TraceGen1Time) accumulated_time()->start(); |
duke@435 | 149 | |
duke@435 | 150 | // Let the size policy know we're starting |
duke@435 | 151 | size_policy->major_collection_begin(); |
duke@435 | 152 | |
duke@435 | 153 | // When collecting the permanent generation methodOops may be moving, |
duke@435 | 154 | // so we either have to flush all bcp data or convert it into bci. |
duke@435 | 155 | CodeCache::gc_prologue(); |
duke@435 | 156 | Threads::gc_prologue(); |
duke@435 | 157 | BiasedLocking::preserve_marks(); |
duke@435 | 158 | |
duke@435 | 159 | // Capture heap size before collection for printing. |
duke@435 | 160 | size_t prev_used = heap->used(); |
duke@435 | 161 | |
duke@435 | 162 | // Capture perm gen size before collection for sizing. |
duke@435 | 163 | size_t perm_gen_prev_used = perm_gen->used_in_bytes(); |
duke@435 | 164 | |
duke@435 | 165 | // For PrintGCDetails |
duke@435 | 166 | size_t old_gen_prev_used = old_gen->used_in_bytes(); |
duke@435 | 167 | size_t young_gen_prev_used = young_gen->used_in_bytes(); |
duke@435 | 168 | |
duke@435 | 169 | allocate_stacks(); |
duke@435 | 170 | |
duke@435 | 171 | NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); |
duke@435 | 172 | COMPILER2_PRESENT(DerivedPointerTable::clear()); |
duke@435 | 173 | |
duke@435 | 174 | ref_processor()->enable_discovery(); |
ysr@892 | 175 | ref_processor()->setup_policy(clear_all_softrefs); |
duke@435 | 176 | |
duke@435 | 177 | mark_sweep_phase1(clear_all_softrefs); |
duke@435 | 178 | |
duke@435 | 179 | mark_sweep_phase2(); |
duke@435 | 180 | |
duke@435 | 181 | // Don't add any more derived pointers during phase3 |
duke@435 | 182 | COMPILER2_PRESENT(assert(DerivedPointerTable::is_active(), "Sanity")); |
duke@435 | 183 | COMPILER2_PRESENT(DerivedPointerTable::set_active(false)); |
duke@435 | 184 | |
duke@435 | 185 | mark_sweep_phase3(); |
duke@435 | 186 | |
duke@435 | 187 | mark_sweep_phase4(); |
duke@435 | 188 | |
duke@435 | 189 | restore_marks(); |
duke@435 | 190 | |
duke@435 | 191 | deallocate_stacks(); |
duke@435 | 192 | |
jmasa@698 | 193 | if (ZapUnusedHeapArea) { |
jmasa@698 | 194 | // Do a complete mangle (top to end) because the usage for |
jmasa@698 | 195 | // scratch does not maintain a top pointer. |
jmasa@698 | 196 | young_gen->to_space()->mangle_unused_area_complete(); |
jmasa@698 | 197 | } |
jmasa@698 | 198 | |
duke@435 | 199 | eden_empty = young_gen->eden_space()->is_empty(); |
duke@435 | 200 | if (!eden_empty) { |
duke@435 | 201 | eden_empty = absorb_live_data_from_eden(size_policy, young_gen, old_gen); |
duke@435 | 202 | } |
duke@435 | 203 | |
duke@435 | 204 | // Update heap occupancy information which is used as |
duke@435 | 205 | // input to soft ref clearing policy at the next gc. |
duke@435 | 206 | Universe::update_heap_info_at_gc(); |
duke@435 | 207 | |
duke@435 | 208 | survivors_empty = young_gen->from_space()->is_empty() && |
jmasa@698 | 209 | young_gen->to_space()->is_empty(); |
duke@435 | 210 | young_gen_empty = eden_empty && survivors_empty; |
duke@435 | 211 | |
duke@435 | 212 | BarrierSet* bs = heap->barrier_set(); |
duke@435 | 213 | if (bs->is_a(BarrierSet::ModRef)) { |
duke@435 | 214 | ModRefBarrierSet* modBS = (ModRefBarrierSet*)bs; |
duke@435 | 215 | MemRegion old_mr = heap->old_gen()->reserved(); |
duke@435 | 216 | MemRegion perm_mr = heap->perm_gen()->reserved(); |
duke@435 | 217 | assert(perm_mr.end() <= old_mr.start(), "Generations out of order"); |
duke@435 | 218 | |
duke@435 | 219 | if (young_gen_empty) { |
duke@435 | 220 | modBS->clear(MemRegion(perm_mr.start(), old_mr.end())); |
duke@435 | 221 | } else { |
duke@435 | 222 | modBS->invalidate(MemRegion(perm_mr.start(), old_mr.end())); |
duke@435 | 223 | } |
duke@435 | 224 | } |
duke@435 | 225 | |
duke@435 | 226 | BiasedLocking::restore_marks(); |
duke@435 | 227 | Threads::gc_epilogue(); |
duke@435 | 228 | CodeCache::gc_epilogue(); |
duke@435 | 229 | |
duke@435 | 230 | COMPILER2_PRESENT(DerivedPointerTable::update_pointers()); |
duke@435 | 231 | |
duke@435 | 232 | ref_processor()->enqueue_discovered_references(NULL); |
duke@435 | 233 | |
duke@435 | 234 | // Update time of last GC |
duke@435 | 235 | reset_millis_since_last_gc(); |
duke@435 | 236 | |
duke@435 | 237 | // Let the size policy know we're done |
duke@435 | 238 | size_policy->major_collection_end(old_gen->used_in_bytes(), gc_cause); |
duke@435 | 239 | |
duke@435 | 240 | if (UseAdaptiveSizePolicy) { |
duke@435 | 241 | |
duke@435 | 242 | if (PrintAdaptiveSizePolicy) { |
duke@435 | 243 | gclog_or_tty->print("AdaptiveSizeStart: "); |
duke@435 | 244 | gclog_or_tty->stamp(); |
duke@435 | 245 | gclog_or_tty->print_cr(" collection: %d ", |
duke@435 | 246 | heap->total_collections()); |
duke@435 | 247 | if (Verbose) { |
duke@435 | 248 | gclog_or_tty->print("old_gen_capacity: %d young_gen_capacity: %d" |
duke@435 | 249 | " perm_gen_capacity: %d ", |
duke@435 | 250 | old_gen->capacity_in_bytes(), young_gen->capacity_in_bytes(), |
duke@435 | 251 | perm_gen->capacity_in_bytes()); |
duke@435 | 252 | } |
duke@435 | 253 | } |
duke@435 | 254 | |
duke@435 | 255 | // Don't check if the size_policy is ready here. Let |
duke@435 | 256 | // the size_policy check that internally. |
duke@435 | 257 | if (UseAdaptiveGenerationSizePolicyAtMajorCollection && |
duke@435 | 258 | ((gc_cause != GCCause::_java_lang_system_gc) || |
duke@435 | 259 | UseAdaptiveSizePolicyWithSystemGC)) { |
duke@435 | 260 | // Calculate optimal free space amounts |
duke@435 | 261 | assert(young_gen->max_size() > |
duke@435 | 262 | young_gen->from_space()->capacity_in_bytes() + |
duke@435 | 263 | young_gen->to_space()->capacity_in_bytes(), |
duke@435 | 264 | "Sizes of space in young gen are out-of-bounds"); |
duke@435 | 265 | size_t max_eden_size = young_gen->max_size() - |
duke@435 | 266 | young_gen->from_space()->capacity_in_bytes() - |
duke@435 | 267 | young_gen->to_space()->capacity_in_bytes(); |
duke@435 | 268 | size_policy->compute_generation_free_space(young_gen->used_in_bytes(), |
duke@435 | 269 | young_gen->eden_space()->used_in_bytes(), |
duke@435 | 270 | old_gen->used_in_bytes(), |
duke@435 | 271 | perm_gen->used_in_bytes(), |
duke@435 | 272 | young_gen->eden_space()->capacity_in_bytes(), |
duke@435 | 273 | old_gen->max_gen_size(), |
duke@435 | 274 | max_eden_size, |
duke@435 | 275 | true /* full gc*/, |
duke@435 | 276 | gc_cause); |
duke@435 | 277 | |
duke@435 | 278 | heap->resize_old_gen(size_policy->calculated_old_free_size_in_bytes()); |
duke@435 | 279 | |
duke@435 | 280 | // Don't resize the young generation at an major collection. A |
duke@435 | 281 | // desired young generation size may have been calculated but |
duke@435 | 282 | // resizing the young generation complicates the code because the |
duke@435 | 283 | // resizing of the old generation may have moved the boundary |
duke@435 | 284 | // between the young generation and the old generation. Let the |
duke@435 | 285 | // young generation resizing happen at the minor collections. |
duke@435 | 286 | } |
duke@435 | 287 | if (PrintAdaptiveSizePolicy) { |
duke@435 | 288 | gclog_or_tty->print_cr("AdaptiveSizeStop: collection: %d ", |
duke@435 | 289 | heap->total_collections()); |
duke@435 | 290 | } |
duke@435 | 291 | } |
duke@435 | 292 | |
duke@435 | 293 | if (UsePerfData) { |
duke@435 | 294 | heap->gc_policy_counters()->update_counters(); |
duke@435 | 295 | heap->gc_policy_counters()->update_old_capacity( |
duke@435 | 296 | old_gen->capacity_in_bytes()); |
duke@435 | 297 | heap->gc_policy_counters()->update_young_capacity( |
duke@435 | 298 | young_gen->capacity_in_bytes()); |
duke@435 | 299 | } |
duke@435 | 300 | |
duke@435 | 301 | heap->resize_all_tlabs(); |
duke@435 | 302 | |
duke@435 | 303 | // We collected the perm gen, so we'll resize it here. |
duke@435 | 304 | perm_gen->compute_new_size(perm_gen_prev_used); |
duke@435 | 305 | |
duke@435 | 306 | if (TraceGen1Time) accumulated_time()->stop(); |
duke@435 | 307 | |
duke@435 | 308 | if (PrintGC) { |
duke@435 | 309 | if (PrintGCDetails) { |
duke@435 | 310 | // Don't print a GC timestamp here. This is after the GC so |
duke@435 | 311 | // would be confusing. |
duke@435 | 312 | young_gen->print_used_change(young_gen_prev_used); |
duke@435 | 313 | old_gen->print_used_change(old_gen_prev_used); |
duke@435 | 314 | } |
duke@435 | 315 | heap->print_heap_change(prev_used); |
duke@435 | 316 | // Do perm gen after heap becase prev_used does |
duke@435 | 317 | // not include the perm gen (done this way in the other |
duke@435 | 318 | // collectors). |
duke@435 | 319 | if (PrintGCDetails) { |
duke@435 | 320 | perm_gen->print_used_change(perm_gen_prev_used); |
duke@435 | 321 | } |
duke@435 | 322 | } |
duke@435 | 323 | |
duke@435 | 324 | // Track memory usage and detect low memory |
duke@435 | 325 | MemoryService::track_memory_usage(); |
duke@435 | 326 | heap->update_counters(); |
duke@435 | 327 | |
duke@435 | 328 | if (PrintGCDetails) { |
duke@435 | 329 | if (size_policy->print_gc_time_limit_would_be_exceeded()) { |
duke@435 | 330 | if (size_policy->gc_time_limit_exceeded()) { |
duke@435 | 331 | gclog_or_tty->print_cr(" GC time is exceeding GCTimeLimit " |
duke@435 | 332 | "of %d%%", GCTimeLimit); |
duke@435 | 333 | } else { |
duke@435 | 334 | gclog_or_tty->print_cr(" GC time would exceed GCTimeLimit " |
duke@435 | 335 | "of %d%%", GCTimeLimit); |
duke@435 | 336 | } |
duke@435 | 337 | } |
duke@435 | 338 | size_policy->set_print_gc_time_limit_would_be_exceeded(false); |
duke@435 | 339 | } |
duke@435 | 340 | } |
duke@435 | 341 | |
duke@435 | 342 | if (VerifyAfterGC && heap->total_collections() >= VerifyGCStartAt) { |
duke@435 | 343 | HandleMark hm; // Discard invalid handles created during verification |
duke@435 | 344 | gclog_or_tty->print(" VerifyAfterGC:"); |
duke@435 | 345 | Universe::verify(false); |
duke@435 | 346 | } |
duke@435 | 347 | |
duke@435 | 348 | // Re-verify object start arrays |
duke@435 | 349 | if (VerifyObjectStartArray && |
duke@435 | 350 | VerifyAfterGC) { |
duke@435 | 351 | old_gen->verify_object_start_array(); |
duke@435 | 352 | perm_gen->verify_object_start_array(); |
duke@435 | 353 | } |
duke@435 | 354 | |
jmasa@698 | 355 | if (ZapUnusedHeapArea) { |
jmasa@698 | 356 | old_gen->object_space()->check_mangled_unused_area_complete(); |
jmasa@698 | 357 | perm_gen->object_space()->check_mangled_unused_area_complete(); |
jmasa@698 | 358 | } |
jmasa@698 | 359 | |
duke@435 | 360 | NOT_PRODUCT(ref_processor()->verify_no_references_recorded()); |
duke@435 | 361 | |
duke@435 | 362 | if (PrintHeapAtGC) { |
duke@435 | 363 | Universe::print_heap_after_gc(); |
duke@435 | 364 | } |
duke@435 | 365 | } |
duke@435 | 366 | |
duke@435 | 367 | bool PSMarkSweep::absorb_live_data_from_eden(PSAdaptiveSizePolicy* size_policy, |
duke@435 | 368 | PSYoungGen* young_gen, |
duke@435 | 369 | PSOldGen* old_gen) { |
duke@435 | 370 | MutableSpace* const eden_space = young_gen->eden_space(); |
duke@435 | 371 | assert(!eden_space->is_empty(), "eden must be non-empty"); |
duke@435 | 372 | assert(young_gen->virtual_space()->alignment() == |
duke@435 | 373 | old_gen->virtual_space()->alignment(), "alignments do not match"); |
duke@435 | 374 | |
duke@435 | 375 | if (!(UseAdaptiveSizePolicy && UseAdaptiveGCBoundary)) { |
duke@435 | 376 | return false; |
duke@435 | 377 | } |
duke@435 | 378 | |
duke@435 | 379 | // Both generations must be completely committed. |
duke@435 | 380 | if (young_gen->virtual_space()->uncommitted_size() != 0) { |
duke@435 | 381 | return false; |
duke@435 | 382 | } |
duke@435 | 383 | if (old_gen->virtual_space()->uncommitted_size() != 0) { |
duke@435 | 384 | return false; |
duke@435 | 385 | } |
duke@435 | 386 | |
duke@435 | 387 | // Figure out how much to take from eden. Include the average amount promoted |
duke@435 | 388 | // in the total; otherwise the next young gen GC will simply bail out to a |
duke@435 | 389 | // full GC. |
duke@435 | 390 | const size_t alignment = old_gen->virtual_space()->alignment(); |
duke@435 | 391 | const size_t eden_used = eden_space->used_in_bytes(); |
jcoomes@916 | 392 | const size_t promoted = (size_t)size_policy->avg_promoted()->padded_average(); |
duke@435 | 393 | const size_t absorb_size = align_size_up(eden_used + promoted, alignment); |
duke@435 | 394 | const size_t eden_capacity = eden_space->capacity_in_bytes(); |
duke@435 | 395 | |
duke@435 | 396 | if (absorb_size >= eden_capacity) { |
duke@435 | 397 | return false; // Must leave some space in eden. |
duke@435 | 398 | } |
duke@435 | 399 | |
duke@435 | 400 | const size_t new_young_size = young_gen->capacity_in_bytes() - absorb_size; |
duke@435 | 401 | if (new_young_size < young_gen->min_gen_size()) { |
duke@435 | 402 | return false; // Respect young gen minimum size. |
duke@435 | 403 | } |
duke@435 | 404 | |
duke@435 | 405 | if (TraceAdaptiveGCBoundary && Verbose) { |
duke@435 | 406 | gclog_or_tty->print(" absorbing " SIZE_FORMAT "K: " |
duke@435 | 407 | "eden " SIZE_FORMAT "K->" SIZE_FORMAT "K " |
duke@435 | 408 | "from " SIZE_FORMAT "K, to " SIZE_FORMAT "K " |
duke@435 | 409 | "young_gen " SIZE_FORMAT "K->" SIZE_FORMAT "K ", |
duke@435 | 410 | absorb_size / K, |
duke@435 | 411 | eden_capacity / K, (eden_capacity - absorb_size) / K, |
duke@435 | 412 | young_gen->from_space()->used_in_bytes() / K, |
duke@435 | 413 | young_gen->to_space()->used_in_bytes() / K, |
duke@435 | 414 | young_gen->capacity_in_bytes() / K, new_young_size / K); |
duke@435 | 415 | } |
duke@435 | 416 | |
duke@435 | 417 | // Fill the unused part of the old gen. |
duke@435 | 418 | MutableSpace* const old_space = old_gen->object_space(); |
jcoomes@916 | 419 | HeapWord* const unused_start = old_space->top(); |
jcoomes@916 | 420 | size_t const unused_words = pointer_delta(old_space->end(), unused_start); |
duke@435 | 421 | |
jcoomes@916 | 422 | if (unused_words > 0) { |
jcoomes@916 | 423 | if (unused_words < CollectedHeap::min_fill_size()) { |
jcoomes@916 | 424 | return false; // If the old gen cannot be filled, must give up. |
jcoomes@916 | 425 | } |
jcoomes@916 | 426 | CollectedHeap::fill_with_objects(unused_start, unused_words); |
duke@435 | 427 | } |
duke@435 | 428 | |
duke@435 | 429 | // Take the live data from eden and set both top and end in the old gen to |
duke@435 | 430 | // eden top. (Need to set end because reset_after_change() mangles the region |
duke@435 | 431 | // from end to virtual_space->high() in debug builds). |
duke@435 | 432 | HeapWord* const new_top = eden_space->top(); |
duke@435 | 433 | old_gen->virtual_space()->expand_into(young_gen->virtual_space(), |
duke@435 | 434 | absorb_size); |
duke@435 | 435 | young_gen->reset_after_change(); |
duke@435 | 436 | old_space->set_top(new_top); |
duke@435 | 437 | old_space->set_end(new_top); |
duke@435 | 438 | old_gen->reset_after_change(); |
duke@435 | 439 | |
duke@435 | 440 | // Update the object start array for the filler object and the data from eden. |
duke@435 | 441 | ObjectStartArray* const start_array = old_gen->start_array(); |
jcoomes@916 | 442 | for (HeapWord* p = unused_start; p < new_top; p += oop(p)->size()) { |
jcoomes@916 | 443 | start_array->allocate_block(p); |
duke@435 | 444 | } |
duke@435 | 445 | |
duke@435 | 446 | // Could update the promoted average here, but it is not typically updated at |
duke@435 | 447 | // full GCs and the value to use is unclear. Something like |
duke@435 | 448 | // |
duke@435 | 449 | // cur_promoted_avg + absorb_size / number_of_scavenges_since_last_full_gc. |
duke@435 | 450 | |
duke@435 | 451 | size_policy->set_bytes_absorbed_from_eden(absorb_size); |
duke@435 | 452 | return true; |
duke@435 | 453 | } |
duke@435 | 454 | |
duke@435 | 455 | void PSMarkSweep::allocate_stacks() { |
duke@435 | 456 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 457 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 458 | |
duke@435 | 459 | PSYoungGen* young_gen = heap->young_gen(); |
duke@435 | 460 | |
duke@435 | 461 | MutableSpace* to_space = young_gen->to_space(); |
duke@435 | 462 | _preserved_marks = (PreservedMark*)to_space->top(); |
duke@435 | 463 | _preserved_count = 0; |
duke@435 | 464 | |
duke@435 | 465 | // We want to calculate the size in bytes first. |
duke@435 | 466 | _preserved_count_max = pointer_delta(to_space->end(), to_space->top(), sizeof(jbyte)); |
duke@435 | 467 | // Now divide by the size of a PreservedMark |
duke@435 | 468 | _preserved_count_max /= sizeof(PreservedMark); |
duke@435 | 469 | |
duke@435 | 470 | _preserved_mark_stack = NULL; |
duke@435 | 471 | _preserved_oop_stack = NULL; |
duke@435 | 472 | |
duke@435 | 473 | _marking_stack = new (ResourceObj::C_HEAP) GrowableArray<oop>(4000, true); |
duke@435 | 474 | |
duke@435 | 475 | int size = SystemDictionary::number_of_classes() * 2; |
duke@435 | 476 | _revisit_klass_stack = new (ResourceObj::C_HEAP) GrowableArray<Klass*>(size, true); |
duke@435 | 477 | } |
duke@435 | 478 | |
duke@435 | 479 | |
duke@435 | 480 | void PSMarkSweep::deallocate_stacks() { |
duke@435 | 481 | if (_preserved_oop_stack) { |
duke@435 | 482 | delete _preserved_mark_stack; |
duke@435 | 483 | _preserved_mark_stack = NULL; |
duke@435 | 484 | delete _preserved_oop_stack; |
duke@435 | 485 | _preserved_oop_stack = NULL; |
duke@435 | 486 | } |
duke@435 | 487 | |
duke@435 | 488 | delete _marking_stack; |
duke@435 | 489 | delete _revisit_klass_stack; |
duke@435 | 490 | } |
duke@435 | 491 | |
duke@435 | 492 | void PSMarkSweep::mark_sweep_phase1(bool clear_all_softrefs) { |
duke@435 | 493 | // Recursively traverse all live objects and mark them |
duke@435 | 494 | EventMark m("1 mark object"); |
duke@435 | 495 | TraceTime tm("phase 1", PrintGCDetails && Verbose, true, gclog_or_tty); |
duke@435 | 496 | trace(" 1"); |
duke@435 | 497 | |
duke@435 | 498 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 499 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 500 | |
duke@435 | 501 | // General strong roots. |
duke@435 | 502 | Universe::oops_do(mark_and_push_closure()); |
duke@435 | 503 | ReferenceProcessor::oops_do(mark_and_push_closure()); |
duke@435 | 504 | JNIHandles::oops_do(mark_and_push_closure()); // Global (strong) JNI handles |
duke@435 | 505 | Threads::oops_do(mark_and_push_closure()); |
duke@435 | 506 | ObjectSynchronizer::oops_do(mark_and_push_closure()); |
duke@435 | 507 | FlatProfiler::oops_do(mark_and_push_closure()); |
duke@435 | 508 | Management::oops_do(mark_and_push_closure()); |
duke@435 | 509 | JvmtiExport::oops_do(mark_and_push_closure()); |
duke@435 | 510 | SystemDictionary::always_strong_oops_do(mark_and_push_closure()); |
duke@435 | 511 | vmSymbols::oops_do(mark_and_push_closure()); |
duke@435 | 512 | |
duke@435 | 513 | // Flush marking stack. |
duke@435 | 514 | follow_stack(); |
duke@435 | 515 | |
duke@435 | 516 | // Process reference objects found during marking |
duke@435 | 517 | { |
ysr@892 | 518 | ref_processor()->setup_policy(clear_all_softrefs); |
duke@435 | 519 | ref_processor()->process_discovered_references( |
ysr@888 | 520 | is_alive_closure(), mark_and_push_closure(), follow_stack_closure(), NULL); |
duke@435 | 521 | } |
duke@435 | 522 | |
duke@435 | 523 | // Follow system dictionary roots and unload classes |
duke@435 | 524 | bool purged_class = SystemDictionary::do_unloading(is_alive_closure()); |
duke@435 | 525 | |
duke@435 | 526 | // Follow code cache roots |
duke@435 | 527 | CodeCache::do_unloading(is_alive_closure(), mark_and_push_closure(), |
duke@435 | 528 | purged_class); |
duke@435 | 529 | follow_stack(); // Flush marking stack |
duke@435 | 530 | |
duke@435 | 531 | // Update subklass/sibling/implementor links of live klasses |
duke@435 | 532 | follow_weak_klass_links(); |
duke@435 | 533 | assert(_marking_stack->is_empty(), "just drained"); |
duke@435 | 534 | |
duke@435 | 535 | // Visit symbol and interned string tables and delete unmarked oops |
duke@435 | 536 | SymbolTable::unlink(is_alive_closure()); |
duke@435 | 537 | StringTable::unlink(is_alive_closure()); |
duke@435 | 538 | |
duke@435 | 539 | assert(_marking_stack->is_empty(), "stack should be empty by now"); |
duke@435 | 540 | } |
duke@435 | 541 | |
duke@435 | 542 | |
duke@435 | 543 | void PSMarkSweep::mark_sweep_phase2() { |
duke@435 | 544 | EventMark m("2 compute new addresses"); |
duke@435 | 545 | TraceTime tm("phase 2", PrintGCDetails && Verbose, true, gclog_or_tty); |
duke@435 | 546 | trace("2"); |
duke@435 | 547 | |
duke@435 | 548 | // Now all live objects are marked, compute the new object addresses. |
duke@435 | 549 | |
duke@435 | 550 | // It is imperative that we traverse perm_gen LAST. If dead space is |
duke@435 | 551 | // allowed a range of dead object may get overwritten by a dead int |
duke@435 | 552 | // array. If perm_gen is not traversed last a klassOop may get |
duke@435 | 553 | // overwritten. This is fine since it is dead, but if the class has dead |
duke@435 | 554 | // instances we have to skip them, and in order to find their size we |
duke@435 | 555 | // need the klassOop! |
duke@435 | 556 | // |
duke@435 | 557 | // It is not required that we traverse spaces in the same order in |
duke@435 | 558 | // phase2, phase3 and phase4, but the ValidateMarkSweep live oops |
duke@435 | 559 | // tracking expects us to do so. See comment under phase4. |
duke@435 | 560 | |
duke@435 | 561 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 562 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 563 | |
duke@435 | 564 | PSOldGen* old_gen = heap->old_gen(); |
duke@435 | 565 | PSPermGen* perm_gen = heap->perm_gen(); |
duke@435 | 566 | |
duke@435 | 567 | // Begin compacting into the old gen |
duke@435 | 568 | PSMarkSweepDecorator::set_destination_decorator_tenured(); |
duke@435 | 569 | |
duke@435 | 570 | // This will also compact the young gen spaces. |
duke@435 | 571 | old_gen->precompact(); |
duke@435 | 572 | |
duke@435 | 573 | // Compact the perm gen into the perm gen |
duke@435 | 574 | PSMarkSweepDecorator::set_destination_decorator_perm_gen(); |
duke@435 | 575 | |
duke@435 | 576 | perm_gen->precompact(); |
duke@435 | 577 | } |
duke@435 | 578 | |
duke@435 | 579 | // This should be moved to the shared markSweep code! |
duke@435 | 580 | class PSAlwaysTrueClosure: public BoolObjectClosure { |
duke@435 | 581 | public: |
duke@435 | 582 | void do_object(oop p) { ShouldNotReachHere(); } |
duke@435 | 583 | bool do_object_b(oop p) { return true; } |
duke@435 | 584 | }; |
duke@435 | 585 | static PSAlwaysTrueClosure always_true; |
duke@435 | 586 | |
duke@435 | 587 | void PSMarkSweep::mark_sweep_phase3() { |
duke@435 | 588 | // Adjust the pointers to reflect the new locations |
duke@435 | 589 | EventMark m("3 adjust pointers"); |
duke@435 | 590 | TraceTime tm("phase 3", PrintGCDetails && Verbose, true, gclog_or_tty); |
duke@435 | 591 | trace("3"); |
duke@435 | 592 | |
duke@435 | 593 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 594 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 595 | |
duke@435 | 596 | PSYoungGen* young_gen = heap->young_gen(); |
duke@435 | 597 | PSOldGen* old_gen = heap->old_gen(); |
duke@435 | 598 | PSPermGen* perm_gen = heap->perm_gen(); |
duke@435 | 599 | |
duke@435 | 600 | // General strong roots. |
duke@435 | 601 | Universe::oops_do(adjust_root_pointer_closure()); |
duke@435 | 602 | ReferenceProcessor::oops_do(adjust_root_pointer_closure()); |
duke@435 | 603 | JNIHandles::oops_do(adjust_root_pointer_closure()); // Global (strong) JNI handles |
duke@435 | 604 | Threads::oops_do(adjust_root_pointer_closure()); |
duke@435 | 605 | ObjectSynchronizer::oops_do(adjust_root_pointer_closure()); |
duke@435 | 606 | FlatProfiler::oops_do(adjust_root_pointer_closure()); |
duke@435 | 607 | Management::oops_do(adjust_root_pointer_closure()); |
duke@435 | 608 | JvmtiExport::oops_do(adjust_root_pointer_closure()); |
duke@435 | 609 | // SO_AllClasses |
duke@435 | 610 | SystemDictionary::oops_do(adjust_root_pointer_closure()); |
duke@435 | 611 | vmSymbols::oops_do(adjust_root_pointer_closure()); |
duke@435 | 612 | |
duke@435 | 613 | // Now adjust pointers in remaining weak roots. (All of which should |
duke@435 | 614 | // have been cleared if they pointed to non-surviving objects.) |
duke@435 | 615 | // Global (weak) JNI handles |
duke@435 | 616 | JNIHandles::weak_oops_do(&always_true, adjust_root_pointer_closure()); |
duke@435 | 617 | |
duke@435 | 618 | CodeCache::oops_do(adjust_pointer_closure()); |
duke@435 | 619 | SymbolTable::oops_do(adjust_root_pointer_closure()); |
duke@435 | 620 | StringTable::oops_do(adjust_root_pointer_closure()); |
duke@435 | 621 | ref_processor()->weak_oops_do(adjust_root_pointer_closure()); |
duke@435 | 622 | PSScavenge::reference_processor()->weak_oops_do(adjust_root_pointer_closure()); |
duke@435 | 623 | |
duke@435 | 624 | adjust_marks(); |
duke@435 | 625 | |
duke@435 | 626 | young_gen->adjust_pointers(); |
duke@435 | 627 | old_gen->adjust_pointers(); |
duke@435 | 628 | perm_gen->adjust_pointers(); |
duke@435 | 629 | } |
duke@435 | 630 | |
duke@435 | 631 | void PSMarkSweep::mark_sweep_phase4() { |
duke@435 | 632 | EventMark m("4 compact heap"); |
duke@435 | 633 | TraceTime tm("phase 4", PrintGCDetails && Verbose, true, gclog_or_tty); |
duke@435 | 634 | trace("4"); |
duke@435 | 635 | |
duke@435 | 636 | // All pointers are now adjusted, move objects accordingly |
duke@435 | 637 | |
duke@435 | 638 | // It is imperative that we traverse perm_gen first in phase4. All |
duke@435 | 639 | // classes must be allocated earlier than their instances, and traversing |
duke@435 | 640 | // perm_gen first makes sure that all klassOops have moved to their new |
duke@435 | 641 | // location before any instance does a dispatch through it's klass! |
duke@435 | 642 | ParallelScavengeHeap* heap = (ParallelScavengeHeap*)Universe::heap(); |
duke@435 | 643 | assert(heap->kind() == CollectedHeap::ParallelScavengeHeap, "Sanity"); |
duke@435 | 644 | |
duke@435 | 645 | PSYoungGen* young_gen = heap->young_gen(); |
duke@435 | 646 | PSOldGen* old_gen = heap->old_gen(); |
duke@435 | 647 | PSPermGen* perm_gen = heap->perm_gen(); |
duke@435 | 648 | |
duke@435 | 649 | perm_gen->compact(); |
duke@435 | 650 | old_gen->compact(); |
duke@435 | 651 | young_gen->compact(); |
duke@435 | 652 | } |
duke@435 | 653 | |
duke@435 | 654 | jlong PSMarkSweep::millis_since_last_gc() { |
duke@435 | 655 | jlong ret_val = os::javaTimeMillis() - _time_of_last_gc; |
duke@435 | 656 | // XXX See note in genCollectedHeap::millis_since_last_gc(). |
duke@435 | 657 | if (ret_val < 0) { |
duke@435 | 658 | NOT_PRODUCT(warning("time warp: %d", ret_val);) |
duke@435 | 659 | return 0; |
duke@435 | 660 | } |
duke@435 | 661 | return ret_val; |
duke@435 | 662 | } |
duke@435 | 663 | |
duke@435 | 664 | void PSMarkSweep::reset_millis_since_last_gc() { |
duke@435 | 665 | _time_of_last_gc = os::javaTimeMillis(); |
duke@435 | 666 | } |