1 /* 2 * Copyright (c) 2015, 2017, Red Hat, Inc. and/or its affiliates. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. 7 * 8 * This code is distributed in the hope that it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 11 * version 2 for more details (a copy is included in the LICENSE file that 12 * accompanied this code). 13 * 14 * You should have received a copy of the GNU General Public License version 15 * 2 along with this work; if not, write to the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * questions. 21 * 22 */ 23 24 #ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAP_INLINE_HPP 25 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAP_INLINE_HPP 26 27 #include "classfile/javaClasses.inline.hpp" 28 #include "gc/g1/suspendibleThreadSet.hpp" 29 #include "gc/shared/markBitMap.inline.hpp" 30 #include "gc/shared/threadLocalAllocBuffer.inline.hpp" 31 #include "gc/shenandoah/brooksPointer.inline.hpp" 32 #include "gc/shenandoah/shenandoahBarrierSet.inline.hpp" 33 #include "gc/shenandoah/shenandoahCollectionSet.hpp" 34 #include "gc/shenandoah/shenandoahCollectionSet.inline.hpp" 35 #include "gc/shenandoah/shenandoahConnectionMatrix.inline.hpp" 36 #include "gc/shenandoah/shenandoahHeap.hpp" 37 #include "gc/shenandoah/shenandoahHeapRegionSet.hpp" 38 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp" 39 #include "gc/shenandoah/shenandoahStringDedup.hpp" 40 #include "gc/shenandoah/shenandoahUtils.hpp" 41 #include "oops/oop.inline.hpp" 42 #include "runtime/atomic.hpp" 43 #include "runtime/interfaceSupport.hpp" 44 #include "runtime/prefetch.hpp" 45 #include "runtime/prefetch.inline.hpp" 46 #include "runtime/thread.hpp" 47 #include "utilities/copy.hpp" 48 49 template <class T> 50 void ShenandoahUpdateRefsClosure::do_oop_work(T* p) { 51 T o = oopDesc::load_heap_oop(p); 52 if (! oopDesc::is_null(o)) { 53 oop obj = oopDesc::decode_heap_oop_not_null(o); 54 _heap->update_oop_ref_not_null(p, obj); 55 } 56 } 57 58 void ShenandoahUpdateRefsClosure::do_oop(oop* p) { do_oop_work(p); } 59 void ShenandoahUpdateRefsClosure::do_oop(narrowOop* p) { do_oop_work(p); } 60 61 /* 62 * Marks the object. Returns true if the object has not been marked before and has 63 * been marked by this thread. Returns false if the object has already been marked, 64 * or if a competing thread succeeded in marking this object. 65 */ 66 inline bool ShenandoahHeap::mark(oop obj) { 67 #ifdef ASSERT 68 if (! oopDesc::unsafe_equals(obj, oopDesc::bs()->read_barrier(obj))) { 69 tty->print_cr("heap region containing obj:"); 70 ShenandoahHeapRegion* obj_region = heap_region_containing(obj); 71 obj_region->print(); 72 tty->print_cr("heap region containing forwardee:"); 73 ShenandoahHeapRegion* forward_region = heap_region_containing(oopDesc::bs()->read_barrier(obj)); 74 forward_region->print(); 75 } 76 #endif 77 78 assert(oopDesc::unsafe_equals(obj, oopDesc::bs()->read_barrier(obj)), "only mark forwarded copy of objects"); 79 return mark_no_checks(obj); 80 } 81 82 inline bool ShenandoahHeap::mark_no_checks(oop obj) { 83 HeapWord* addr = (HeapWord*) obj; 84 return !allocated_after_mark_start(addr) && _mark_bit_map.parMark(addr); 85 } 86 87 inline bool ShenandoahHeap::is_marked(oop obj) const { 88 HeapWord* addr = (HeapWord*) obj; 89 return allocated_after_mark_start(addr) || _mark_bit_map.isMarked(addr); 90 } 91 92 inline bool ShenandoahHeap::need_update_refs() const { 93 return _need_update_refs; 94 } 95 96 inline size_t ShenandoahHeap::heap_region_index_containing(const void* addr) const { 97 uintptr_t region_start = ((uintptr_t) addr); 98 uintptr_t index = (region_start - (uintptr_t) base()) >> ShenandoahHeapRegion::region_size_bytes_shift(); 99 #ifdef ASSERT 100 if (index >= num_regions()) { 101 tty->print_cr("heap region does not contain address, heap base: "PTR_FORMAT \ 102 ", real bottom of first region: "PTR_FORMAT", num_regions: "SIZE_FORMAT", region_size: "SIZE_FORMAT, 103 p2i(base()), 104 p2i(_ordered_regions->get(0)->bottom()), 105 num_regions(), 106 ShenandoahHeapRegion::region_size_bytes()); 107 } 108 #endif 109 assert(index < num_regions(), "heap region index must be in range"); 110 return index; 111 } 112 113 inline ShenandoahHeapRegion* ShenandoahHeap::heap_region_containing(const void* addr) const { 114 size_t index = heap_region_index_containing(addr); 115 ShenandoahHeapRegion* result = _ordered_regions->get(index); 116 #ifdef ASSERT 117 if (!(addr >= result->bottom() && addr < result->end())) { 118 tty->print_cr("heap region does not contain address, heap base: "PTR_FORMAT \ 119 ", real bottom of first region: "PTR_FORMAT", num_regions: "SIZE_FORMAT, 120 p2i(base()), 121 p2i(_ordered_regions->get(0)->bottom()), 122 num_regions()); 123 } 124 #endif 125 assert(addr >= result->bottom() && addr < result->end(), "address must be in found region"); 126 return result; 127 } 128 129 template <class T> 130 inline oop ShenandoahHeap::update_oop_ref_not_null(T* p, oop obj) { 131 if (in_collection_set(obj)) { 132 oop forw = ShenandoahBarrierSet::resolve_oop_static_not_null(obj); 133 assert(! oopDesc::unsafe_equals(forw, obj) || is_full_gc_in_progress() || cancelled_concgc(), "expect forwarded object"); 134 obj = forw; 135 oopDesc::encode_store_heap_oop(p, obj); 136 } 137 #ifdef ASSERT 138 else { 139 assert(oopDesc::unsafe_equals(obj, ShenandoahBarrierSet::resolve_oop_static_not_null(obj)), "expect not forwarded"); 140 } 141 #endif 142 return obj; 143 } 144 145 template <class T> 146 inline oop ShenandoahHeap::maybe_update_oop_ref(T* p) { 147 T o = oopDesc::load_heap_oop(p); 148 if (! oopDesc::is_null(o)) { 149 oop obj = oopDesc::decode_heap_oop_not_null(o); 150 return maybe_update_oop_ref_not_null(p, obj); 151 } else { 152 return NULL; 153 } 154 } 155 156 template <class T> 157 inline oop ShenandoahHeap::evac_update_oop_ref(T* p, bool& evac) { 158 evac = false; 159 T o = oopDesc::load_heap_oop(p); 160 if (! oopDesc::is_null(o)) { 161 oop heap_oop = oopDesc::decode_heap_oop_not_null(o); 162 if (in_collection_set(heap_oop)) { 163 oop forwarded_oop = ShenandoahBarrierSet::resolve_oop_static_not_null(heap_oop); // read brooks ptr 164 if (oopDesc::unsafe_equals(forwarded_oop, heap_oop)) { 165 forwarded_oop = evacuate_object(heap_oop, Thread::current(), evac); 166 } 167 oop prev = atomic_compare_exchange_oop(forwarded_oop, p, heap_oop); 168 if (prev == heap_oop) { 169 return forwarded_oop; 170 } else { 171 return NULL; 172 } 173 } 174 return heap_oop; 175 } else { 176 return NULL; 177 } 178 } 179 180 inline oop ShenandoahHeap::atomic_compare_exchange_oop(oop n, oop* addr, oop c) { 181 return (oop) Atomic::cmpxchg_ptr(n, addr, c); 182 } 183 184 inline oop ShenandoahHeap::atomic_compare_exchange_oop(oop n, narrowOop* addr, oop c) { 185 narrowOop cmp = oopDesc::encode_heap_oop(c); 186 narrowOop val = oopDesc::encode_heap_oop(n); 187 return oopDesc::decode_heap_oop((narrowOop) Atomic::cmpxchg(val, addr, cmp)); 188 } 189 190 template <class T> 191 inline oop ShenandoahHeap::maybe_update_oop_ref_not_null(T* p, oop heap_oop) { 192 193 assert((! is_in(p)) || (! in_collection_set(p)) 194 || is_full_gc_in_progress(), 195 "never update refs in from-space, unless evacuation has been cancelled"); 196 197 #ifdef ASSERT 198 if (! is_in(heap_oop)) { 199 print_heap_regions_on(tty); 200 tty->print_cr("object not in heap: "PTR_FORMAT", referenced by: "PTR_FORMAT, p2i((HeapWord*) heap_oop), p2i(p)); 201 assert(is_in(heap_oop), "object must be in heap"); 202 } 203 #endif 204 assert(is_in(heap_oop), "only ever call this on objects in the heap"); 205 if (in_collection_set(heap_oop)) { 206 oop forwarded_oop = ShenandoahBarrierSet::resolve_oop_static_not_null(heap_oop); // read brooks ptr 207 if (oopDesc::unsafe_equals(forwarded_oop, heap_oop)) { 208 // E.g. during evacuation. 209 return forwarded_oop; 210 } 211 212 assert(! oopDesc::unsafe_equals(forwarded_oop, heap_oop) || is_full_gc_in_progress(), "expect forwarded object"); 213 214 log_develop_trace(gc)("Updating old ref: "PTR_FORMAT" pointing to "PTR_FORMAT" to new ref: "PTR_FORMAT, 215 p2i(p), p2i(heap_oop), p2i(forwarded_oop)); 216 217 assert(oopDesc::is_oop(forwarded_oop), "oop required"); 218 assert(is_in(forwarded_oop), "forwardee must be in heap"); 219 assert(oopDesc::bs()->is_safe(forwarded_oop), "forwardee must not be in collection set"); 220 // If this fails, another thread wrote to p before us, it will be logged in SATB and the 221 // reference be updated later. 222 oop result = atomic_compare_exchange_oop(forwarded_oop, p, heap_oop); 223 224 if (oopDesc::unsafe_equals(result, heap_oop)) { // CAS successful. 225 return forwarded_oop; 226 } else { 227 // Note: we used to assert the following here. This doesn't work because sometimes, during 228 // marking/updating-refs, it can happen that a Java thread beats us with an arraycopy, 229 // which first copies the array, which potentially contains from-space refs, and only afterwards 230 // updates all from-space refs to to-space refs, which leaves a short window where the new array 231 // elements can be from-space. 232 // assert(oopDesc::is_null(result) || 233 // oopDesc::unsafe_equals(result, ShenandoahBarrierSet::resolve_oop_static_not_null(result)), 234 // "expect not forwarded"); 235 return NULL; 236 } 237 } else { 238 assert(oopDesc::unsafe_equals(heap_oop, ShenandoahBarrierSet::resolve_oop_static_not_null(heap_oop)), 239 "expect not forwarded"); 240 return heap_oop; 241 } 242 } 243 244 inline bool ShenandoahHeap::cancelled_concgc() const { 245 return OrderAccess::load_acquire((jbyte*) &_cancelled_concgc) == CANCELLED; 246 } 247 248 inline bool ShenandoahHeap::check_cancelled_concgc_and_yield(bool sts_active) { 249 if (! (sts_active && ShenandoahSuspendibleWorkers)) { 250 return cancelled_concgc(); 251 } 252 jbyte prev = Atomic::cmpxchg((jbyte)NOT_CANCELLED, &_cancelled_concgc, (jbyte)CANCELLABLE); 253 if (prev == CANCELLABLE || prev == NOT_CANCELLED) { 254 255 if (SuspendibleThreadSet::should_yield()) { 256 SuspendibleThreadSet::yield(); 257 } 258 259 // Back to CANCELLABLE. The thread that poked NOT_CANCELLED first gets 260 // to restore to CANCELLABLE. 261 if (prev == CANCELLABLE) { 262 OrderAccess::release_store_fence(&_cancelled_concgc, CANCELLABLE); 263 } 264 return false; 265 } else { 266 return true; 267 } 268 } 269 270 inline bool ShenandoahHeap::try_cancel_concgc() { 271 while (true) { 272 jbyte prev = Atomic::cmpxchg((jbyte)CANCELLED, &_cancelled_concgc, (jbyte)CANCELLABLE); 273 if (prev == CANCELLABLE) return true; 274 else if (prev == CANCELLED) return false; 275 assert(ShenandoahSuspendibleWorkers, "should not get here when not using suspendible workers"); 276 assert(prev == NOT_CANCELLED, "must be NOT_CANCELLED"); 277 { 278 // We need to provide a safepoint here, otherwise we might 279 // spin forever if a SP is pending. 280 ThreadBlockInVM sp(JavaThread::current()); 281 SpinPause(); 282 } 283 } 284 } 285 286 inline void ShenandoahHeap::clear_cancelled_concgc() { 287 OrderAccess::release_store_fence(&_cancelled_concgc, CANCELLABLE); 288 } 289 290 inline HeapWord* ShenandoahHeap::allocate_from_gclab(Thread* thread, size_t size) { 291 if (UseTLAB) { 292 if (!thread->gclab().is_initialized()) { 293 assert(!thread->is_Java_thread() && !thread->is_Worker_thread(), 294 "Performance: thread should have GCLAB: %s", thread->name()); 295 // No GCLABs in this thread, fallback to shared allocation 296 return NULL; 297 } 298 HeapWord* obj = thread->gclab().allocate(size); 299 if (obj != NULL) { 300 return obj; 301 } 302 // Otherwise... 303 return allocate_from_gclab_slow(thread, size); 304 } else { 305 return NULL; 306 } 307 } 308 309 inline oop ShenandoahHeap::evacuate_object(oop p, Thread* thread, bool& evacuated) { 310 evacuated = false; 311 312 size_t size_no_fwdptr = (size_t) p->size(); 313 size_t size_with_fwdptr = size_no_fwdptr + BrooksPointer::word_size(); 314 315 assert(!heap_region_containing(p)->is_humongous(), "never evacuate humongous objects"); 316 317 bool alloc_from_gclab = true; 318 HeapWord* filler = allocate_from_gclab(thread, size_with_fwdptr); 319 if (filler == NULL) { 320 filler = allocate_memory(size_with_fwdptr, _alloc_shared_gc); 321 alloc_from_gclab = false; 322 } 323 324 #ifdef ASSERT 325 // Checking that current Java thread does not hold Threads_lock when we get here. 326 // If that ever be the case, we'd deadlock in oom_during_evacuation. 327 if ((! Thread::current()->is_GC_task_thread()) && (! Thread::current()->is_ConcurrentGC_thread())) { 328 assert(! Threads_lock->owned_by_self() 329 || SafepointSynchronize::is_at_safepoint(), "must not hold Threads_lock here"); 330 } 331 #endif 332 333 if (filler == NULL) { 334 oom_during_evacuation(); 335 // If this is a Java thread, it should have waited 336 // until all GC threads are done, and then we 337 // return the forwardee. 338 oop resolved = ShenandoahBarrierSet::resolve_oop_static(p); 339 return resolved; 340 } 341 342 // Copy the object and initialize its forwarding ptr: 343 HeapWord* copy = filler + BrooksPointer::word_size(); 344 oop copy_val = oop(copy); 345 346 Copy::aligned_disjoint_words((HeapWord*) p, copy, size_no_fwdptr); 347 BrooksPointer::initialize(oop(copy)); 348 349 log_develop_trace(gc, compaction)("Copy object: " PTR_FORMAT " -> " PTR_FORMAT, 350 p2i(p), p2i(copy)); 351 352 // String dedup support 353 bool need_str_dedup = false; 354 if (ShenandoahStringDedup::is_enabled() 355 && java_lang_String::is_instance_inlined(copy_val)) { 356 // We need to increase age before CAS to avoid race condition. 357 // Once new copy is published, other threads may set hash code, 358 // or perform locking, etc. which will race age bits manipulation. 359 copy_val->incr_age(); 360 361 need_str_dedup = ShenandoahStringDedup::is_candidate(copy_val); 362 } 363 364 // Try to install the new forwarding pointer. 365 oop result = BrooksPointer::try_update_forwardee(p, copy_val); 366 367 if (oopDesc::unsafe_equals(result, p)) { 368 // Successfully evacuated. Our copy is now the public one! 369 evacuated = true; 370 log_develop_trace(gc, compaction)("Copy object: " PTR_FORMAT " -> " PTR_FORMAT " succeeded", 371 p2i(p), p2i(copy)); 372 373 // Only dedup evacuated string 374 if (need_str_dedup) { 375 // Shenandoah evacuates objects inside and outside of safepoints. 376 // But string dedup protocol requires deduplication outside of safepoints, 377 // so we need to queue candidates during safepoints. 378 if (SafepointSynchronize::is_at_safepoint()) { 379 assert(thread->is_Worker_thread(), "Must be a worker thread during a safepoint"); 380 // Use worker thread id instead of worker_id to avoid passing down worker_id. 381 // This may cause imbalance among the queues, but it is okay, since deduplication is 382 // single threaded. 383 ShenandoahStringDedup::enqueue_from_safepoint(copy_val, thread->as_Worker_thread()->id()); 384 } else { 385 ShenandoahStringDedup::deduplicate(copy_val); 386 } 387 } 388 389 #ifdef ASSERT 390 assert(oopDesc::is_oop(copy_val), "expect oop"); 391 assert(p->klass() == copy_val->klass(), "Should have the same class p: "PTR_FORMAT", copy: "PTR_FORMAT, 392 p2i(p), p2i(copy)); 393 #endif 394 return copy_val; 395 } else { 396 // Failed to evacuate. We need to deal with the object that is left behind. Since this 397 // new allocation is certainly after TAMS, it will be considered live in the next cycle. 398 // But if it happens to contain references to evacuated regions, those references would 399 // not get updated for this stale copy during this cycle, and we will crash while scanning 400 // it the next cycle. 401 // 402 // For GCLAB allocations, it is enough to rollback the allocation ptr. Either the next 403 // object will overwrite this stale copy, or the filler object on LAB retirement will 404 // do this. For non-GCLAB allocations, we have no way to retract the allocation, and 405 // have to explicitly overwrite the copy with the filler object. With that overwrite, 406 // we have to keep the fwdptr initialized and pointing to our (stale) copy. 407 if (alloc_from_gclab) { 408 thread->gclab().rollback(size_with_fwdptr); 409 } else { 410 fill_with_object(copy, size_no_fwdptr); 411 } 412 log_develop_trace(gc, compaction)("Copy object: " PTR_FORMAT " -> " PTR_FORMAT " failed, use other: " PTR_FORMAT, 413 p2i(p), p2i(copy), p2i(result)); 414 return result; 415 } 416 } 417 418 inline bool ShenandoahHeap::requires_marking(const void* entry) const { 419 // TODO: Make this faster! It's used in a hot path. 420 // TODO: it's not strictly matrix-related, but used only in partial (i.e. matrix) GCs. 421 if (is_concurrent_partial_in_progress()) { 422 assert(! in_collection_set((oop) entry), "must not get cset objects here"); 423 // assert(free_regions()->contains(heap_region_containing(entry)), "expect to-space object"); 424 return true; 425 } else if (concurrent_mark_in_progress()) { 426 return ! is_marked(oop(entry)); 427 } else { 428 return false; 429 } 430 } 431 432 bool ShenandoahHeap::region_in_collection_set(size_t region_index) const { 433 assert(collection_set() != NULL, "Sanity"); 434 return collection_set()->is_in(region_index); 435 } 436 437 bool ShenandoahHeap::in_collection_set(ShenandoahHeapRegion* r) const { 438 return region_in_collection_set(r->region_number()); 439 } 440 441 template <class T> 442 inline bool ShenandoahHeap::in_collection_set(T p) const { 443 HeapWord* obj = (HeapWord*) p; 444 assert(collection_set() != NULL, "Sanity"); 445 assert(is_in(obj), "should be in heap"); 446 447 return collection_set()->is_in(obj); 448 } 449 450 inline bool ShenandoahHeap::concurrent_mark_in_progress() const { 451 return _concurrent_mark_in_progress != 0; 452 } 453 454 inline bool ShenandoahHeap::is_concurrent_partial_in_progress() const { 455 return _concurrent_partial_in_progress; 456 } 457 458 inline address ShenandoahHeap::update_refs_in_progress_addr() { 459 return (address) &(ShenandoahHeap::heap()->_update_refs_in_progress); 460 } 461 462 inline bool ShenandoahHeap::is_evacuation_in_progress() const { 463 return _evacuation_in_progress != 0; 464 } 465 466 inline address ShenandoahHeap::evacuation_in_progress_addr() { 467 return (address) &(ShenandoahHeap::heap()->_evacuation_in_progress); 468 } 469 470 inline bool ShenandoahHeap::allocated_after_mark_start(HeapWord* addr) const { 471 uintx index = ((uintx) addr) >> ShenandoahHeapRegion::region_size_bytes_shift(); 472 HeapWord* top_at_mark_start = _top_at_mark_starts[index]; 473 bool alloc_after_mark_start = addr >= top_at_mark_start; 474 return alloc_after_mark_start; 475 } 476 477 template<class T> 478 inline void ShenandoahHeap::marked_object_iterate(ShenandoahHeapRegion* region, T* cl) { 479 marked_object_iterate(region, cl, region->top()); 480 } 481 482 template<class T> 483 inline void ShenandoahHeap::marked_object_safe_iterate(ShenandoahHeapRegion* region, T* cl) { 484 marked_object_iterate(region, cl, region->concurrent_iteration_safe_limit()); 485 } 486 487 template<class T> 488 inline void ShenandoahHeap::marked_object_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit) { 489 assert(BrooksPointer::word_offset() < 0, "skip_delta calculation below assumes the forwarding ptr is before obj"); 490 491 assert(! region->is_humongous_continuation(), "no humongous continuation regions here"); 492 assert(is_bitmap_valid(), "only try this with complete marking bitmap"); 493 494 MarkBitMap mark_bit_map = _mark_bit_map; 495 HeapWord* tams = top_at_mark_start(region->bottom()); 496 497 size_t skip_bitmap_delta = BrooksPointer::word_size() + 1; 498 size_t skip_objsize_delta = BrooksPointer::word_size() /* + actual obj.size() below */; 499 HeapWord* start = region->bottom() + BrooksPointer::word_size(); 500 501 HeapWord* end = MIN2(tams + BrooksPointer::word_size(), region->end()); 502 HeapWord* addr = mark_bit_map.getNextMarkedWordAddress(start, end); 503 504 intx dist = ShenandoahMarkScanPrefetch; 505 if (dist > 0) { 506 // Batched scan that prefetches the oop data, anticipating the access to 507 // either header, oop field, or forwarding pointer. Not that we cannot 508 // touch anything in oop, while it still being prefetched to get enough 509 // time for prefetch to work. This is why we try to scan the bitmap linearly, 510 // disregarding the object size. However, since we know forwarding pointer 511 // preceeds the object, we can skip over it. Once we cannot trust the bitmap, 512 // there is no point for prefetching the oop contents, as oop->size() will 513 // touch it prematurely. 514 515 // No variable-length arrays in standard C++, have enough slots to fit 516 // the prefetch distance. 517 static const int SLOT_COUNT = 256; 518 guarantee(dist <= SLOT_COUNT, "adjust slot count"); 519 oop slots[SLOT_COUNT]; 520 521 bool aborting = false; 522 int avail; 523 do { 524 avail = 0; 525 for (int c = 0; (c < dist) && (addr < limit); c++) { 526 Prefetch::read(addr, BrooksPointer::byte_offset()); 527 oop obj = oop(addr); 528 slots[avail++] = obj; 529 if (addr < tams) { 530 addr += skip_bitmap_delta; 531 addr = mark_bit_map.getNextMarkedWordAddress(addr, end); 532 } else { 533 // cannot trust mark bitmap anymore, finish the current stride, 534 // and switch to accurate traversal 535 addr += obj->size() + skip_objsize_delta; 536 aborting = true; 537 } 538 } 539 540 for (int c = 0; c < avail; c++) { 541 do_marked_object(cl, slots[c]); 542 } 543 } while (avail > 0 && !aborting); 544 545 // accurate traversal 546 while (addr < limit) { 547 oop obj = oop(addr); 548 int size = obj->size(); 549 do_marked_object(cl, obj); 550 addr += size + skip_objsize_delta; 551 } 552 } else { 553 while (addr < limit) { 554 oop obj = oop(addr); 555 int size = obj->size(); 556 do_marked_object(cl, obj); 557 addr += size + skip_objsize_delta; 558 if (addr < tams) { 559 addr = mark_bit_map.getNextMarkedWordAddress(addr, end); 560 } 561 } 562 } 563 } 564 565 template<class T> 566 inline void ShenandoahHeap::do_marked_object(T* cl, oop obj) { 567 assert(!oopDesc::is_null(obj), "sanity"); 568 assert(oopDesc::is_oop(obj), "sanity"); 569 assert(is_in(obj), "sanity"); 570 assert(is_marked(obj), "object expected to be marked"); 571 cl->do_object(obj); 572 } 573 574 template <class T> 575 class ShenandoahObjectToOopClosure : public ObjectClosure { 576 T* _cl; 577 public: 578 ShenandoahObjectToOopClosure(T* cl) : _cl(cl) {} 579 580 void do_object(oop obj) { 581 obj->oop_iterate(_cl); 582 } 583 }; 584 585 template <class T> 586 class ShenandoahObjectToOopBoundedClosure : public ObjectClosure { 587 T* _cl; 588 MemRegion _bounds; 589 public: 590 ShenandoahObjectToOopBoundedClosure(T* cl, HeapWord* bottom, HeapWord* top) : 591 _cl(cl), _bounds(bottom, top) {} 592 593 void do_object(oop obj) { 594 obj->oop_iterate(_cl, _bounds); 595 } 596 }; 597 598 template<class T> 599 inline void ShenandoahHeap::marked_object_oop_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* top) { 600 if (region->is_humongous()) { 601 HeapWord* bottom = region->bottom(); 602 if (top > bottom) { 603 region = region->humongous_start_region(); 604 ShenandoahObjectToOopBoundedClosure<T> objs(cl, bottom, top); 605 marked_object_iterate(region, &objs); 606 } 607 } else { 608 ShenandoahObjectToOopClosure<T> objs(cl); 609 marked_object_iterate(region, &objs, top); 610 } 611 } 612 613 template<class T> 614 inline void ShenandoahHeap::marked_object_oop_iterate(ShenandoahHeapRegion* region, T* cl) { 615 marked_object_oop_iterate(region, cl, region->top()); 616 } 617 618 template<class T> 619 inline void ShenandoahHeap::marked_object_oop_safe_iterate(ShenandoahHeapRegion* region, T* cl) { 620 marked_object_oop_iterate(region, cl, region->concurrent_iteration_safe_limit()); 621 } 622 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEAP_INLINE_HPP