1 /*
  2  * Copyright (c) 2015, 2020, Red Hat, Inc. All rights reserved.
  3  * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
  4  *
  5  * This code is free software; you can redistribute it and/or modify it
  6  * under the terms of the GNU General Public License version 2 only, as
  7  * published by the Free Software Foundation.
  8  *
  9  * This code is distributed in the hope that it will be useful, but WITHOUT
 10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 12  * version 2 for more details (a copy is included in the LICENSE file that
 13  * accompanied this code).
 14  *
 15  * You should have received a copy of the GNU General Public License version
 16  * 2 along with this work; if not, write to the Free Software Foundation,
 17  * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 18  *
 19  * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 20  * or visit www.oracle.com if you need additional information or have any
 21  * questions.
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 24 
 25 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_INLINE_HPP
 26 #define SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_INLINE_HPP
 27 
 28 #include "gc/shenandoah/shenandoahHeap.hpp"
 29 
 30 #include "classfile/javaClasses.inline.hpp"
 31 #include "gc/shared/markBitMap.inline.hpp"
 32 #include "gc/shared/threadLocalAllocBuffer.inline.hpp"
 33 #include "gc/shared/suspendibleThreadSet.hpp"
 34 #include "gc/shared/tlab_globals.hpp"
 35 #include "gc/shenandoah/shenandoahAsserts.hpp"
 36 #include "gc/shenandoah/shenandoahBarrierSet.inline.hpp"
 37 #include "gc/shenandoah/shenandoahCollectionSet.inline.hpp"
 38 #include "gc/shenandoah/shenandoahForwarding.inline.hpp"
 39 #include "gc/shenandoah/shenandoahWorkGroup.hpp"
 40 #include "gc/shenandoah/shenandoahHeapRegionSet.inline.hpp"
 41 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp"
 42 #include "gc/shenandoah/shenandoahControlThread.hpp"
 43 #include "gc/shenandoah/shenandoahMarkingContext.inline.hpp"
 44 #include "gc/shenandoah/shenandoahThreadLocalData.hpp"
 45 #include "oops/compressedOops.inline.hpp"
 46 #include "oops/oop.inline.hpp"
 47 #include "runtime/atomic.hpp"
 48 #include "runtime/prefetch.inline.hpp"
 49 #include "runtime/thread.hpp"
 50 #include "utilities/copy.hpp"
 51 #include "utilities/globalDefinitions.hpp"
 52 
 53 inline ShenandoahHeap* ShenandoahHeap::heap() {
 54   return named_heap<ShenandoahHeap>(CollectedHeap::Shenandoah);
 55 }
 56 
 57 inline ShenandoahHeapRegion* ShenandoahRegionIterator::next() {
 58   size_t new_index = Atomic::add(&_index, (size_t) 1, memory_order_relaxed);
 59   // get_region() provides the bounds-check and returns NULL on OOB.
 60   return _heap->get_region(new_index - 1);
 61 }
 62 
 63 inline bool ShenandoahHeap::has_forwarded_objects() const {
 64   return _gc_state.is_set(HAS_FORWARDED);
 65 }
 66 
 67 inline WorkGang* ShenandoahHeap::workers() const {
 68   return _workers;
 69 }
 70 
 71 inline WorkGang* ShenandoahHeap::safepoint_workers() {
 72   return _safepoint_workers;
 73 }
 74 
 75 inline size_t ShenandoahHeap::heap_region_index_containing(const void* addr) const {
 76   uintptr_t region_start = ((uintptr_t) addr);
 77   uintptr_t index = (region_start - (uintptr_t) base()) >> ShenandoahHeapRegion::region_size_bytes_shift();
 78   assert(index < num_regions(), "Region index is in bounds: " PTR_FORMAT, p2i(addr));
 79   return index;
 80 }
 81 
 82 inline ShenandoahHeapRegion* const ShenandoahHeap::heap_region_containing(const void* addr) const {
 83   size_t index = heap_region_index_containing(addr);
 84   ShenandoahHeapRegion* const result = get_region(index);
 85   assert(addr >= result->bottom() && addr < result->end(), "Heap region contains the address: " PTR_FORMAT, p2i(addr));
 86   return result;
 87 }
 88 
 89 inline void ShenandoahHeap::enter_evacuation(Thread* t) {
 90   _oom_evac_handler.enter_evacuation(t);
 91 }
 92 
 93 inline void ShenandoahHeap::leave_evacuation(Thread* t) {
 94   _oom_evac_handler.leave_evacuation(t);
 95 }
 96 
 97 template <class T>
 98 inline void ShenandoahHeap::update_with_forwarded(T* p) {
 99   T o = RawAccess<>::oop_load(p);
100   if (!CompressedOops::is_null(o)) {
101     oop obj = CompressedOops::decode_not_null(o);
102     if (in_collection_set(obj)) {
103       // Corner case: when evacuation fails, there are objects in collection
104       // set that are not really forwarded. We can still go and try and update them
105       // (uselessly) to simplify the common path.
106       shenandoah_assert_forwarded_except(p, obj, cancelled_gc());
107       oop fwd = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
108       shenandoah_assert_not_in_cset_except(p, fwd, cancelled_gc());
109 
110       // Unconditionally store the update: no concurrent updates expected.
111       RawAccess<IS_NOT_NULL>::oop_store(p, fwd);
112     }
113   }
114 }
115 
116 template <class T>
117 inline void ShenandoahHeap::conc_update_with_forwarded(T* p) {
118   T o = RawAccess<>::oop_load(p);
119   if (!CompressedOops::is_null(o)) {
120     oop obj = CompressedOops::decode_not_null(o);
121     if (in_collection_set(obj)) {
122       // Corner case: when evacuation fails, there are objects in collection
123       // set that are not really forwarded. We can still go and try CAS-update them
124       // (uselessly) to simplify the common path.
125       shenandoah_assert_forwarded_except(p, obj, cancelled_gc());
126       oop fwd = ShenandoahBarrierSet::resolve_forwarded_not_null(obj);
127       shenandoah_assert_not_in_cset_except(p, fwd, cancelled_gc());
128 
129       // Sanity check: we should not be updating the cset regions themselves,
130       // unless we are recovering from the evacuation failure.
131       shenandoah_assert_not_in_cset_loc_except(p, !is_in(p) || cancelled_gc());
132 
133       // Either we succeed in updating the reference, or something else gets in our way.
134       // We don't care if that is another concurrent GC update, or another mutator update.
135       atomic_update_oop(fwd, p, obj);
136     }
137   }
138 }
139 
140 // Atomic updates of heap location. This is only expected to work with updating the same
141 // logical object with its forwardee. The reason why we need stronger-than-relaxed memory
142 // ordering has to do with coordination with GC barriers and mutator accesses.
143 //
144 // In essence, stronger CAS access is required to maintain the transitive chains that mutator
145 // accesses build by themselves. To illustrate this point, consider the following example.
146 //
147 // Suppose "o" is the object that has a field "x" and the reference to "o" is stored
148 // to field at "addr", which happens to be Java volatile field. Normally, the accesses to volatile
149 // field at "addr" would be matched with release/acquire barriers. This changes when GC moves
150 // the object under mutator feet.
151 //
152 // Thread 1 (Java)
153 //         // --- previous access starts here
154 //         ...
155 //   T1.1: store(&o.x, 1, mo_relaxed)
156 //   T1.2: store(&addr, o, mo_release) // volatile store
157 //
158 //         // --- new access starts here
159 //         // LRB: copy and install the new copy to fwdptr
160 //   T1.3: var copy = copy(o)
161 //   T1.4: cas(&fwd, t, copy, mo_release) // pointer-mediated publication
162 //         <access continues>
163 //
164 // Thread 2 (GC updater)
165 //   T2.1: var f = load(&fwd, mo_{consume|acquire}) // pointer-mediated acquisition
166 //   T2.2: cas(&addr, o, f, mo_release) // this method
167 //
168 // Thread 3 (Java)
169 //   T3.1: var o = load(&addr, mo_acquire) // volatile read
170 //   T3.2: if (o != null)
171 //   T3.3:   var r = load(&o.x, mo_relaxed)
172 //
173 // r is guaranteed to contain "1".
174 //
175 // Without GC involvement, there is synchronizes-with edge from T1.2 to T3.1,
176 // which guarantees this. With GC involvement, when LRB copies the object and
177 // another thread updates the reference to it, we need to have the transitive edge
178 // from T1.4 to T2.1 (that one is guaranteed by forwarding accesses), plus the edge
179 // from T2.2 to T3.1 (which is brought by this CAS).
180 //
181 // Note that we do not need to "acquire" in these methods, because we do not read the
182 // failure witnesses contents on any path, and "release" is enough.
183 //
184 
185 inline void ShenandoahHeap::atomic_update_oop(oop update, oop* addr, oop compare) {
186   assert(is_aligned(addr, HeapWordSize), "Address should be aligned: " PTR_FORMAT, p2i(addr));
187   Atomic::cmpxchg(addr, compare, update, memory_order_release);
188 }
189 
190 inline void ShenandoahHeap::atomic_update_oop(oop update, narrowOop* addr, narrowOop compare) {
191   assert(is_aligned(addr, sizeof(narrowOop)), "Address should be aligned: " PTR_FORMAT, p2i(addr));
192   narrowOop u = CompressedOops::encode(update);
193   Atomic::cmpxchg(addr, compare, u, memory_order_release);
194 }
195 
196 inline void ShenandoahHeap::atomic_update_oop(oop update, narrowOop* addr, oop compare) {
197   assert(is_aligned(addr, sizeof(narrowOop)), "Address should be aligned: " PTR_FORMAT, p2i(addr));
198   narrowOop c = CompressedOops::encode(compare);
199   narrowOop u = CompressedOops::encode(update);
200   Atomic::cmpxchg(addr, c, u, memory_order_release);
201 }
202 
203 inline bool ShenandoahHeap::atomic_update_oop_check(oop update, oop* addr, oop compare) {
204   assert(is_aligned(addr, HeapWordSize), "Address should be aligned: " PTR_FORMAT, p2i(addr));
205   return (oop) Atomic::cmpxchg(addr, compare, update, memory_order_release) == compare;
206 }
207 
208 inline bool ShenandoahHeap::atomic_update_oop_check(oop update, narrowOop* addr, narrowOop compare) {
209   assert(is_aligned(addr, sizeof(narrowOop)), "Address should be aligned: " PTR_FORMAT, p2i(addr));
210   narrowOop u = CompressedOops::encode(update);
211   return (narrowOop) Atomic::cmpxchg(addr, compare, u, memory_order_release) == compare;
212 }
213 
214 inline bool ShenandoahHeap::atomic_update_oop_check(oop update, narrowOop* addr, oop compare) {
215   assert(is_aligned(addr, sizeof(narrowOop)), "Address should be aligned: " PTR_FORMAT, p2i(addr));
216   narrowOop c = CompressedOops::encode(compare);
217   narrowOop u = CompressedOops::encode(update);
218   return CompressedOops::decode(Atomic::cmpxchg(addr, c, u, memory_order_release)) == compare;
219 }
220 
221 // The memory ordering discussion above does not apply for methods that store NULLs:
222 // then, there is no transitive reads in mutator (as we see NULLs), and we can do
223 // relaxed memory ordering there.
224 
225 inline void ShenandoahHeap::atomic_clear_oop(oop* addr, oop compare) {
226   assert(is_aligned(addr, HeapWordSize), "Address should be aligned: " PTR_FORMAT, p2i(addr));
227   Atomic::cmpxchg(addr, compare, oop(), memory_order_relaxed);
228 }
229 
230 inline void ShenandoahHeap::atomic_clear_oop(narrowOop* addr, oop compare) {
231   assert(is_aligned(addr, sizeof(narrowOop)), "Address should be aligned: " PTR_FORMAT, p2i(addr));
232   narrowOop cmp = CompressedOops::encode(compare);
233   Atomic::cmpxchg(addr, cmp, narrowOop(), memory_order_relaxed);
234 }
235 
236 inline void ShenandoahHeap::atomic_clear_oop(narrowOop* addr, narrowOop compare) {
237   assert(is_aligned(addr, sizeof(narrowOop)), "Address should be aligned: " PTR_FORMAT, p2i(addr));
238   Atomic::cmpxchg(addr, compare, narrowOop(), memory_order_relaxed);
239 }
240 
241 inline bool ShenandoahHeap::cancelled_gc() const {
242   return _cancelled_gc.get() == CANCELLED;
243 }
244 
245 inline bool ShenandoahHeap::check_cancelled_gc_and_yield(bool sts_active) {
246   if (! (sts_active && ShenandoahSuspendibleWorkers)) {
247     return cancelled_gc();
248   }
249 
250   jbyte prev = _cancelled_gc.cmpxchg(NOT_CANCELLED, CANCELLABLE);
251   if (prev == CANCELLABLE || prev == NOT_CANCELLED) {
252     if (SuspendibleThreadSet::should_yield()) {
253       SuspendibleThreadSet::yield();
254     }
255 
256     // Back to CANCELLABLE. The thread that poked NOT_CANCELLED first gets
257     // to restore to CANCELLABLE.
258     if (prev == CANCELLABLE) {
259       _cancelled_gc.set(CANCELLABLE);
260     }
261     return false;
262   } else {
263     return true;
264   }
265 }
266 
267 inline void ShenandoahHeap::clear_cancelled_gc() {
268   _cancelled_gc.set(CANCELLABLE);
269   _oom_evac_handler.clear();
270 }
271 
272 inline HeapWord* ShenandoahHeap::allocate_from_gclab(Thread* thread, size_t size) {
273   assert(UseTLAB, "TLABs should be enabled");
274 
275   PLAB* gclab = ShenandoahThreadLocalData::gclab(thread);
276   if (gclab == NULL) {
277     assert(!thread->is_Java_thread() && !thread->is_Worker_thread(),
278            "Performance: thread should have GCLAB: %s", thread->name());
279     // No GCLABs in this thread, fallback to shared allocation
280     return NULL;
281   }
282   HeapWord* obj = gclab->allocate(size);
283   if (obj != NULL) {
284     return obj;
285   }
286   // Otherwise...
287   return allocate_from_gclab_slow(thread, size);
288 }
289 
290 inline oop ShenandoahHeap::evacuate_object(oop p, Thread* thread) {
291   if (ShenandoahThreadLocalData::is_oom_during_evac(Thread::current())) {
292     // This thread went through the OOM during evac protocol and it is safe to return
293     // the forward pointer. It must not attempt to evacuate any more.
294     return ShenandoahBarrierSet::resolve_forwarded(p);
295   }
296 
297   assert(ShenandoahThreadLocalData::is_evac_allowed(thread), "must be enclosed in oom-evac scope");
298 
299   size_t size = p->size();
300 
301   assert(!heap_region_containing(p)->is_humongous(), "never evacuate humongous objects");
302 
303   bool alloc_from_gclab = true;
304   HeapWord* copy = NULL;
305 
306 #ifdef ASSERT
307   if (ShenandoahOOMDuringEvacALot &&
308       (os::random() & 1) == 0) { // Simulate OOM every ~2nd slow-path call
309         copy = NULL;
310   } else {
311 #endif
312     if (UseTLAB) {
313       copy = allocate_from_gclab(thread, size);
314     }
315     if (copy == NULL) {
316       ShenandoahAllocRequest req = ShenandoahAllocRequest::for_shared_gc(size);
317       copy = allocate_memory(req);
318       alloc_from_gclab = false;
319     }
320 #ifdef ASSERT
321   }
322 #endif
323 
324   if (copy == NULL) {
325     control_thread()->handle_alloc_failure_evac(size);
326 
327     _oom_evac_handler.handle_out_of_memory_during_evacuation();
328 
329     return ShenandoahBarrierSet::resolve_forwarded(p);
330   }
331 
332   // Copy the object:
333   p->copy_disjoint(copy, size);
334 
335   // Try to install the new forwarding pointer.
336   oop copy_val = cast_to_oop(copy);
337   oop result = ShenandoahForwarding::try_update_forwardee(p, copy_val);
338   if (result == copy_val) {
339     // Successfully evacuated. Our copy is now the public one!
340     shenandoah_assert_correct(NULL, copy_val);
341     return copy_val;
342   }  else {
343     // Failed to evacuate. We need to deal with the object that is left behind. Since this
344     // new allocation is certainly after TAMS, it will be considered live in the next cycle.
345     // But if it happens to contain references to evacuated regions, those references would
346     // not get updated for this stale copy during this cycle, and we will crash while scanning
347     // it the next cycle.
348     //
349     // For GCLAB allocations, it is enough to rollback the allocation ptr. Either the next
350     // object will overwrite this stale copy, or the filler object on LAB retirement will
351     // do this. For non-GCLAB allocations, we have no way to retract the allocation, and
352     // have to explicitly overwrite the copy with the filler object. With that overwrite,
353     // we have to keep the fwdptr initialized and pointing to our (stale) copy.
354     if (alloc_from_gclab) {
355       ShenandoahThreadLocalData::gclab(thread)->undo_allocation(copy, size);
356     } else {
357       fill_with_object(copy, size);
358       shenandoah_assert_correct(NULL, copy_val);
359     }
360     shenandoah_assert_correct(NULL, result);
361     return result;
362   }
363 }
364 
365 inline bool ShenandoahHeap::requires_marking(const void* entry) const {
366   oop obj = cast_to_oop(entry);
367   return !_marking_context->is_marked_strong(obj);
368 }
369 
370 inline bool ShenandoahHeap::in_collection_set(oop p) const {
371   assert(collection_set() != NULL, "Sanity");
372   return collection_set()->is_in(p);
373 }
374 
375 inline bool ShenandoahHeap::in_collection_set_loc(void* p) const {
376   assert(collection_set() != NULL, "Sanity");
377   return collection_set()->is_in_loc(p);
378 }
379 
380 inline bool ShenandoahHeap::is_stable() const {
381   return _gc_state.is_clear();
382 }
383 
384 inline bool ShenandoahHeap::is_idle() const {
385   return _gc_state.is_unset(MARKING | EVACUATION | UPDATEREFS);
386 }
387 
388 inline bool ShenandoahHeap::is_concurrent_mark_in_progress() const {
389   return _gc_state.is_set(MARKING);
390 }
391 
392 inline bool ShenandoahHeap::is_evacuation_in_progress() const {
393   return _gc_state.is_set(EVACUATION);
394 }
395 
396 inline bool ShenandoahHeap::is_gc_in_progress_mask(uint mask) const {
397   return _gc_state.is_set(mask);
398 }
399 
400 inline bool ShenandoahHeap::is_degenerated_gc_in_progress() const {
401   return _degenerated_gc_in_progress.is_set();
402 }
403 
404 inline bool ShenandoahHeap::is_full_gc_in_progress() const {
405   return _full_gc_in_progress.is_set();
406 }
407 
408 inline bool ShenandoahHeap::is_full_gc_move_in_progress() const {
409   return _full_gc_move_in_progress.is_set();
410 }
411 
412 inline bool ShenandoahHeap::is_update_refs_in_progress() const {
413   return _gc_state.is_set(UPDATEREFS);
414 }
415 
416 inline bool ShenandoahHeap::is_stw_gc_in_progress() const {
417   return is_full_gc_in_progress() || is_degenerated_gc_in_progress();
418 }
419 
420 inline bool ShenandoahHeap::is_concurrent_strong_root_in_progress() const {
421   return _concurrent_strong_root_in_progress.is_set();
422 }
423 
424 inline bool ShenandoahHeap::is_concurrent_weak_root_in_progress() const {
425   return _gc_state.is_set(WEAK_ROOTS);
426 }
427 
428 template<class T>
429 inline void ShenandoahHeap::marked_object_iterate(ShenandoahHeapRegion* region, T* cl) {
430   marked_object_iterate(region, cl, region->top());
431 }
432 
433 template<class T>
434 inline void ShenandoahHeap::marked_object_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* limit) {
435   assert(! region->is_humongous_continuation(), "no humongous continuation regions here");
436 
437   ShenandoahMarkingContext* const ctx = complete_marking_context();
438   assert(ctx->is_complete(), "sanity");
439 
440   HeapWord* tams = ctx->top_at_mark_start(region);
441 
442   size_t skip_bitmap_delta = 1;
443   HeapWord* start = region->bottom();
444   HeapWord* end = MIN2(tams, region->end());
445 
446   // Step 1. Scan below the TAMS based on bitmap data.
447   HeapWord* limit_bitmap = MIN2(limit, tams);
448 
449   // Try to scan the initial candidate. If the candidate is above the TAMS, it would
450   // fail the subsequent "< limit_bitmap" checks, and fall through to Step 2.
451   HeapWord* cb = ctx->get_next_marked_addr(start, end);
452 
453   intx dist = ShenandoahMarkScanPrefetch;
454   if (dist > 0) {
455     // Batched scan that prefetches the oop data, anticipating the access to
456     // either header, oop field, or forwarding pointer. Not that we cannot
457     // touch anything in oop, while it still being prefetched to get enough
458     // time for prefetch to work. This is why we try to scan the bitmap linearly,
459     // disregarding the object size. However, since we know forwarding pointer
460     // preceeds the object, we can skip over it. Once we cannot trust the bitmap,
461     // there is no point for prefetching the oop contents, as oop->size() will
462     // touch it prematurely.
463 
464     // No variable-length arrays in standard C++, have enough slots to fit
465     // the prefetch distance.
466     static const int SLOT_COUNT = 256;
467     guarantee(dist <= SLOT_COUNT, "adjust slot count");
468     HeapWord* slots[SLOT_COUNT];
469 
470     int avail;
471     do {
472       avail = 0;
473       for (int c = 0; (c < dist) && (cb < limit_bitmap); c++) {
474         Prefetch::read(cb, oopDesc::mark_offset_in_bytes());
475         slots[avail++] = cb;
476         cb += skip_bitmap_delta;
477         if (cb < limit_bitmap) {
478           cb = ctx->get_next_marked_addr(cb, limit_bitmap);
479         }
480       }
481 
482       for (int c = 0; c < avail; c++) {
483         assert (slots[c] < tams,  "only objects below TAMS here: "  PTR_FORMAT " (" PTR_FORMAT ")", p2i(slots[c]), p2i(tams));
484         assert (slots[c] < limit, "only objects below limit here: " PTR_FORMAT " (" PTR_FORMAT ")", p2i(slots[c]), p2i(limit));
485         oop obj = cast_to_oop(slots[c]);
486         assert(oopDesc::is_oop(obj), "sanity");
487         assert(ctx->is_marked(obj), "object expected to be marked");
488         cl->do_object(obj);
489       }
490     } while (avail > 0);
491   } else {
492     while (cb < limit_bitmap) {
493       assert (cb < tams,  "only objects below TAMS here: "  PTR_FORMAT " (" PTR_FORMAT ")", p2i(cb), p2i(tams));
494       assert (cb < limit, "only objects below limit here: " PTR_FORMAT " (" PTR_FORMAT ")", p2i(cb), p2i(limit));
495       oop obj = cast_to_oop(cb);
496       assert(oopDesc::is_oop(obj), "sanity");
497       assert(ctx->is_marked(obj), "object expected to be marked");
498       cl->do_object(obj);
499       cb += skip_bitmap_delta;
500       if (cb < limit_bitmap) {
501         cb = ctx->get_next_marked_addr(cb, limit_bitmap);
502       }
503     }
504   }
505 
506   // Step 2. Accurate size-based traversal, happens past the TAMS.
507   // This restarts the scan at TAMS, which makes sure we traverse all objects,
508   // regardless of what happened at Step 1.
509   HeapWord* cs = tams;
510   while (cs < limit) {
511     assert (cs >= tams, "only objects past TAMS here: "   PTR_FORMAT " (" PTR_FORMAT ")", p2i(cs), p2i(tams));
512     assert (cs < limit, "only objects below limit here: " PTR_FORMAT " (" PTR_FORMAT ")", p2i(cs), p2i(limit));
513     oop obj = cast_to_oop(cs);
514     assert(oopDesc::is_oop(obj), "sanity");
515     assert(ctx->is_marked(obj), "object expected to be marked");
516     int size = obj->size();
517     cl->do_object(obj);
518     cs += size;
519   }
520 }
521 
522 template <class T>
523 class ShenandoahObjectToOopClosure : public ObjectClosure {
524   T* _cl;
525 public:
526   ShenandoahObjectToOopClosure(T* cl) : _cl(cl) {}
527 
528   void do_object(oop obj) {
529     obj->oop_iterate(_cl);
530   }
531 };
532 
533 template <class T>
534 class ShenandoahObjectToOopBoundedClosure : public ObjectClosure {
535   T* _cl;
536   MemRegion _bounds;
537 public:
538   ShenandoahObjectToOopBoundedClosure(T* cl, HeapWord* bottom, HeapWord* top) :
539     _cl(cl), _bounds(bottom, top) {}
540 
541   void do_object(oop obj) {
542     obj->oop_iterate(_cl, _bounds);
543   }
544 };
545 
546 template<class T>
547 inline void ShenandoahHeap::marked_object_oop_iterate(ShenandoahHeapRegion* region, T* cl, HeapWord* top) {
548   if (region->is_humongous()) {
549     HeapWord* bottom = region->bottom();
550     if (top > bottom) {
551       region = region->humongous_start_region();
552       ShenandoahObjectToOopBoundedClosure<T> objs(cl, bottom, top);
553       marked_object_iterate(region, &objs);
554     }
555   } else {
556     ShenandoahObjectToOopClosure<T> objs(cl);
557     marked_object_iterate(region, &objs, top);
558   }
559 }
560 
561 inline ShenandoahHeapRegion* const ShenandoahHeap::get_region(size_t region_idx) const {
562   if (region_idx < _num_regions) {
563     return _regions[region_idx];
564   } else {
565     return NULL;
566   }
567 }
568 
569 inline void ShenandoahHeap::mark_complete_marking_context() {
570   _marking_context->mark_complete();
571 }
572 
573 inline void ShenandoahHeap::mark_incomplete_marking_context() {
574   _marking_context->mark_incomplete();
575 }
576 
577 inline ShenandoahMarkingContext* ShenandoahHeap::complete_marking_context() const {
578   assert (_marking_context->is_complete()," sanity");
579   return _marking_context;
580 }
581 
582 inline ShenandoahMarkingContext* ShenandoahHeap::marking_context() const {
583   return _marking_context;
584 }
585 
586 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHHEAP_INLINE_HPP