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comparison src/share/vm/memory/referenceProcessor.hpp @ 17976:8e20ef014b08

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8043239: G1: Missing post barrier in processing of j.l.ref.Reference objects Summary: Removed all write barriers during reference processing and added explicit write barriers when iterating through the discovered list. Reviewed-by: pliden, jmasa, tschatzl
author brutisso
date Wed, 11 Jun 2014 10:46:47 +0200
parents d60ecdb2773e
children 52b4284cb496 0982ec23da03 01dcaba9b3f3
comparison
equal deleted inserted replaced
17975:bd4d69d9cb7d 17976:8e20ef014b08
97 oop _next; 97 oop _next;
98 HeapWord* _referent_addr; 98 HeapWord* _referent_addr;
99 oop _referent; 99 oop _referent;
100 OopClosure* _keep_alive; 100 OopClosure* _keep_alive;
101 BoolObjectClosure* _is_alive; 101 BoolObjectClosure* _is_alive;
102 bool _discovered_list_needs_post_barrier;
103 102
104 DEBUG_ONLY( 103 DEBUG_ONLY(
105 oop _first_seen; // cyclic linked list check 104 oop _first_seen; // cyclic linked list check
106 ) 105 )
107 106
111 ) 110 )
112 111
113 public: 112 public:
114 inline DiscoveredListIterator(DiscoveredList& refs_list, 113 inline DiscoveredListIterator(DiscoveredList& refs_list,
115 OopClosure* keep_alive, 114 OopClosure* keep_alive,
116 BoolObjectClosure* is_alive, 115 BoolObjectClosure* is_alive):
117 bool discovered_list_needs_post_barrier = false):
118 _refs_list(refs_list), 116 _refs_list(refs_list),
119 _prev_next(refs_list.adr_head()), 117 _prev_next(refs_list.adr_head()),
120 _prev(NULL), 118 _prev(NULL),
121 _ref(refs_list.head()), 119 _ref(refs_list.head()),
122 #ifdef ASSERT 120 #ifdef ASSERT
126 _processed(0), 124 _processed(0),
127 _removed(0), 125 _removed(0),
128 #endif 126 #endif
129 _next(NULL), 127 _next(NULL),
130 _keep_alive(keep_alive), 128 _keep_alive(keep_alive),
131 _is_alive(is_alive), 129 _is_alive(is_alive)
132 _discovered_list_needs_post_barrier(discovered_list_needs_post_barrier)
133 { } 130 { }
134 131
135 // End Of List. 132 // End Of List.
136 inline bool has_next() const { return _ref != NULL; } 133 inline bool has_next() const { return _ref != NULL; }
137 134
227 224
228 bool _discovering_refs; // true when discovery enabled 225 bool _discovering_refs; // true when discovery enabled
229 bool _discovery_is_atomic; // if discovery is atomic wrt 226 bool _discovery_is_atomic; // if discovery is atomic wrt
230 // other collectors in configuration 227 // other collectors in configuration
231 bool _discovery_is_mt; // true if reference discovery is MT. 228 bool _discovery_is_mt; // true if reference discovery is MT.
232
233 // If true, setting "next" field of a discovered refs list requires
234 // write post barrier. (Must be true if used in a collector in which
235 // elements of a discovered list may be moved during discovery: for
236 // example, a collector like Garbage-First that moves objects during a
237 // long-term concurrent marking phase that does weak reference
238 // discovery.)
239 bool _discovered_list_needs_post_barrier;
240 229
241 bool _enqueuing_is_done; // true if all weak references enqueued 230 bool _enqueuing_is_done; // true if all weak references enqueued
242 bool _processing_is_mt; // true during phases when 231 bool _processing_is_mt; // true during phases when
243 // reference processing is MT. 232 // reference processing is MT.
244 uint _next_id; // round-robin mod _num_q counter in 233 uint _next_id; // round-robin mod _num_q counter in
380 const char* list_name(uint i); 369 const char* list_name(uint i);
381 370
382 void enqueue_discovered_reflists(HeapWord* pending_list_addr, AbstractRefProcTaskExecutor* task_executor); 371 void enqueue_discovered_reflists(HeapWord* pending_list_addr, AbstractRefProcTaskExecutor* task_executor);
383 372
384 protected: 373 protected:
385 // Set the 'discovered' field of the given reference to
386 // the given value - emitting post barriers depending upon
387 // the value of _discovered_list_needs_post_barrier.
388 void set_discovered(oop ref, oop value);
389
390 // "Preclean" the given discovered reference list 374 // "Preclean" the given discovered reference list
391 // by removing references with strongly reachable referents. 375 // by removing references with strongly reachable referents.
392 // Currently used in support of CMS only. 376 // Currently used in support of CMS only.
393 void preclean_discovered_reflist(DiscoveredList& refs_list, 377 void preclean_discovered_reflist(DiscoveredList& refs_list,
394 BoolObjectClosure* is_alive, 378 BoolObjectClosure* is_alive,
425 // Default parameters give you a vanilla reference processor. 409 // Default parameters give you a vanilla reference processor.
426 ReferenceProcessor(MemRegion span, 410 ReferenceProcessor(MemRegion span,
427 bool mt_processing = false, uint mt_processing_degree = 1, 411 bool mt_processing = false, uint mt_processing_degree = 1,
428 bool mt_discovery = false, uint mt_discovery_degree = 1, 412 bool mt_discovery = false, uint mt_discovery_degree = 1,
429 bool atomic_discovery = true, 413 bool atomic_discovery = true,
430 BoolObjectClosure* is_alive_non_header = NULL, 414 BoolObjectClosure* is_alive_non_header = NULL);
431 bool discovered_list_needs_post_barrier = false);
432 415
433 // RefDiscoveryPolicy values 416 // RefDiscoveryPolicy values
434 enum DiscoveryPolicy { 417 enum DiscoveryPolicy {
435 ReferenceBasedDiscovery = 0, 418 ReferenceBasedDiscovery = 0,
436 ReferentBasedDiscovery = 1, 419 ReferentBasedDiscovery = 1,