61 } 62 63 CardTable::CardValue* G1HotCardCache::insert(CardValue* card_ptr) { 64 uint count = _card_counts.add_card_count(card_ptr); 65 if (!_card_counts.is_hot(count)) { 66 // The card is not hot so do not store it in the cache; 67 // return it for immediate refining. 68 return card_ptr; 69 } 70 // Otherwise, the card is hot. 71 size_t index = Atomic::add(&_hot_cache_idx, 1u) - 1; 72 size_t masked_index = index & (_hot_cache_size - 1); 73 CardValue* current_ptr = _hot_cache[masked_index]; 74 75 // Try to store the new card pointer into the cache. Compare-and-swap to guard 76 // against the unlikely event of a race resulting in another card pointer to 77 // have already been written to the cache. In this case we will return 78 // card_ptr in favor of the other option, which would be starting over. This 79 // should be OK since card_ptr will likely be the older card already when/if 80 // this ever happens. 81 CardValue* previous_ptr = Atomic::cmpxchg(card_ptr, 82 &_hot_cache[masked_index], 83 current_ptr); 84 return (previous_ptr == current_ptr) ? previous_ptr : card_ptr; 85 } 86 87 void G1HotCardCache::drain(G1CardTableEntryClosure* cl, uint worker_id) { 88 assert(default_use_cache(), "Drain only necessary if we use the hot card cache."); 89 90 assert(_hot_cache != NULL, "Logic"); 91 assert(!use_cache(), "cache should be disabled"); 92 93 while (_hot_cache_par_claimed_idx < _hot_cache_size) { 94 size_t end_idx = Atomic::add(&_hot_cache_par_claimed_idx, 95 _hot_cache_par_chunk_size); 96 size_t start_idx = end_idx - _hot_cache_par_chunk_size; 97 // The current worker has successfully claimed the chunk [start_idx..end_idx) 98 end_idx = MIN2(end_idx, _hot_cache_size); 99 for (size_t i = start_idx; i < end_idx; i++) { 100 CardValue* card_ptr = _hot_cache[i]; 101 if (card_ptr != NULL) { 102 cl->do_card_ptr(card_ptr, worker_id); 103 } else { | 61 } 62 63 CardTable::CardValue* G1HotCardCache::insert(CardValue* card_ptr) { 64 uint count = _card_counts.add_card_count(card_ptr); 65 if (!_card_counts.is_hot(count)) { 66 // The card is not hot so do not store it in the cache; 67 // return it for immediate refining. 68 return card_ptr; 69 } 70 // Otherwise, the card is hot. 71 size_t index = Atomic::add(&_hot_cache_idx, 1u) - 1; 72 size_t masked_index = index & (_hot_cache_size - 1); 73 CardValue* current_ptr = _hot_cache[masked_index]; 74 75 // Try to store the new card pointer into the cache. Compare-and-swap to guard 76 // against the unlikely event of a race resulting in another card pointer to 77 // have already been written to the cache. In this case we will return 78 // card_ptr in favor of the other option, which would be starting over. This 79 // should be OK since card_ptr will likely be the older card already when/if 80 // this ever happens. 81 CardValue* previous_ptr = Atomic::cmpxchg(&_hot_cache[masked_index], 82 current_ptr, 83 card_ptr); 84 return (previous_ptr == current_ptr) ? previous_ptr : card_ptr; 85 } 86 87 void G1HotCardCache::drain(G1CardTableEntryClosure* cl, uint worker_id) { 88 assert(default_use_cache(), "Drain only necessary if we use the hot card cache."); 89 90 assert(_hot_cache != NULL, "Logic"); 91 assert(!use_cache(), "cache should be disabled"); 92 93 while (_hot_cache_par_claimed_idx < _hot_cache_size) { 94 size_t end_idx = Atomic::add(&_hot_cache_par_claimed_idx, 95 _hot_cache_par_chunk_size); 96 size_t start_idx = end_idx - _hot_cache_par_chunk_size; 97 // The current worker has successfully claimed the chunk [start_idx..end_idx) 98 end_idx = MIN2(end_idx, _hot_cache_size); 99 for (size_t i = start_idx; i < end_idx; i++) { 100 CardValue* card_ptr = _hot_cache[i]; 101 if (card_ptr != NULL) { 102 cl->do_card_ptr(card_ptr, worker_id); 103 } else { |