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src/hotspot/share/gc/parallel/psPromotionManager.cpp

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264   }
265 }
266 
267 template <class T> void PSPromotionManager::process_array_chunk_work(
268                                                  oop obj,
269                                                  int start, int end) {
270   assert(start <= end, "invariant");
271   T* const base      = (T*)objArrayOop(obj)->base();
272   T* p               = base + start;
273   T* const chunk_end = base + end;
274   while (p < chunk_end) {
275     claim_or_forward_depth(p);
276     ++p;
277   }
278 }
279 
280 void PSPromotionManager::process_array_chunk(PartialArrayScanTask task) {
281   assert(PSChunkLargeArrays, "invariant");
282 
283   oop old = task.to_source_array();
284   assert(old->is_objArray(), "invariant");
285   assert(old->is_forwarded(), "invariant");
286 
287   TASKQUEUE_STATS_ONLY(++_array_chunks_processed);
288 
289   oop const obj = old->forwardee();
290 
291   int start;
292   int const end = arrayOop(old)->length();
293   if (end > (int) _min_array_size_for_chunking) {
294     // we'll chunk more
295     start = end - _array_chunk_size;
296     assert(start > 0, "invariant");
297     arrayOop(old)->set_length(start);
298     push_depth(ScannerTask(PartialArrayScanTask(old)));
299     TASKQUEUE_STATS_ONLY(++_array_chunk_pushes);
300   } else {
301     // this is the final chunk for this array
302     start = 0;
303     int const actual_length = arrayOop(obj)->length();
304     arrayOop(old)->set_length(actual_length);
305   }
306 
307   if (UseCompressedOops) {
308     process_array_chunk_work<narrowOop>(obj, start, end);
309   } else {
310     process_array_chunk_work<oop>(obj, start, end);
311   }
312 }
313 
314 oop PSPromotionManager::oop_promotion_failed(oop obj, markWord obj_mark) {
315   assert(_old_gen_is_full || PromotionFailureALot, "Sanity");
316 
317   // Attempt to CAS in the header.
318   // This tests if the header is still the same as when
319   // this started.  If it is the same (i.e., no forwarding
320   // pointer has been installed), then this thread owns
321   // it.
322   if (obj->forward_to_atomic(obj, obj_mark) == nullptr) {
323     // We won any races, we "own" this object.
324     assert(obj == obj->forwardee(), "Sanity");
325 
326     _promotion_failed_info.register_copy_failure(obj->size());
327 
328     ContinuationGCSupport::transform_stack_chunk(obj);
329 
330     push_contents(obj);
331 
332     // Save the markWord of promotion-failed objs in _preserved_marks for later
333     // restoration. This way we don't have to walk the young-gen to locate
334     // these promotion-failed objs.
335     _preserved_marks->push_always(obj, obj_mark);
336   }  else {
337     // We lost, someone else "owns" this object
338     guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed.");
339 
340     // No unallocation to worry about.
341     obj = obj->forwardee();
342   }

264   }
265 }
266 
267 template <class T> void PSPromotionManager::process_array_chunk_work(
268                                                  oop obj,
269                                                  int start, int end) {
270   assert(start <= end, "invariant");
271   T* const base      = (T*)objArrayOop(obj)->base();
272   T* p               = base + start;
273   T* const chunk_end = base + end;
274   while (p < chunk_end) {
275     claim_or_forward_depth(p);
276     ++p;
277   }
278 }
279 
280 void PSPromotionManager::process_array_chunk(PartialArrayScanTask task) {
281   assert(PSChunkLargeArrays, "invariant");
282 
283   oop old = task.to_source_array();
284   assert(old->forward_safe_klass()->is_objArray_klass(), "invariant");
285   assert(old->is_forwarded(), "invariant");
286 
287   TASKQUEUE_STATS_ONLY(++_array_chunks_processed);
288 
289   oop const obj = old->forwardee();
290 
291   int start;
292   int const end = arrayOop(old)->length();
293   if (end > (int) _min_array_size_for_chunking) {
294     // we'll chunk more
295     start = end - _array_chunk_size;
296     assert(start > 0, "invariant");
297     arrayOop(old)->set_length(start);
298     push_depth(ScannerTask(PartialArrayScanTask(old)));
299     TASKQUEUE_STATS_ONLY(++_array_chunk_pushes);
300   } else {
301     // this is the final chunk for this array
302     start = 0;
303     int const actual_length = arrayOop(obj)->length();
304     arrayOop(old)->set_length(actual_length);
305   }
306 
307   if (UseCompressedOops) {
308     process_array_chunk_work<narrowOop>(obj, start, end);
309   } else {
310     process_array_chunk_work<oop>(obj, start, end);
311   }
312 }
313 
314 oop PSPromotionManager::oop_promotion_failed(oop obj, markWord obj_mark) {
315   assert(_old_gen_is_full || PromotionFailureALot, "Sanity");
316 
317   // Attempt to CAS in the header.
318   // This tests if the header is still the same as when
319   // this started.  If it is the same (i.e., no forwarding
320   // pointer has been installed), then this thread owns
321   // it.
322   if (obj->forward_to_self_atomic(obj_mark) == nullptr) {
323     // We won any races, we "own" this object.
324     assert(obj == obj->forwardee(), "Sanity");
325 
326     _promotion_failed_info.register_copy_failure(obj->size());
327 
328     ContinuationGCSupport::transform_stack_chunk(obj);
329 
330     push_contents(obj);
331 
332     // Save the markWord of promotion-failed objs in _preserved_marks for later
333     // restoration. This way we don't have to walk the young-gen to locate
334     // these promotion-failed objs.
335     _preserved_marks->push_always(obj, obj_mark);
336   }  else {
337     // We lost, someone else "owns" this object
338     guarantee(obj->is_forwarded(), "Object must be forwarded if the cas failed.");
339 
340     // No unallocation to worry about.
341     obj = obj->forwardee();
342   }
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