1.1 --- a/src/share/vm/gc_implementation/g1/g1HotCardCache.hpp Thu Sep 18 11:27:59 2014 +0200
1.2 +++ b/src/share/vm/gc_implementation/g1/g1HotCardCache.hpp Thu Jan 29 15:05:25 2015 +0100
1.3 @@ -1,5 +1,5 @@
1.4 /*
1.5 - * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
1.6 + * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved.
1.7 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.8 *
1.9 * This code is free software; you can redistribute it and/or modify it
1.10 @@ -54,21 +54,30 @@
1.11 // code, increasing throughput.
1.12
1.13 class G1HotCardCache: public CHeapObj<mtGC> {
1.14 - G1CollectedHeap* _g1h;
1.15 +
1.16 + G1CollectedHeap* _g1h;
1.17 +
1.18 + bool _use_cache;
1.19 +
1.20 + G1CardCounts _card_counts;
1.21
1.22 // The card cache table
1.23 - jbyte** _hot_cache;
1.24 + jbyte** _hot_cache;
1.25
1.26 - int _hot_cache_size;
1.27 - int _n_hot;
1.28 - int _hot_cache_idx;
1.29 + size_t _hot_cache_size;
1.30
1.31 - int _hot_cache_par_chunk_size;
1.32 - volatile int _hot_cache_par_claimed_idx;
1.33 + int _hot_cache_par_chunk_size;
1.34
1.35 - bool _use_cache;
1.36 + // Avoids false sharing when concurrently updating _hot_cache_idx or
1.37 + // _hot_cache_par_claimed_idx. These are never updated at the same time
1.38 + // thus it's not necessary to separate them as well
1.39 + char _pad_before[DEFAULT_CACHE_LINE_SIZE];
1.40
1.41 - G1CardCounts _card_counts;
1.42 + volatile size_t _hot_cache_idx;
1.43 +
1.44 + volatile size_t _hot_cache_par_claimed_idx;
1.45 +
1.46 + char _pad_after[DEFAULT_CACHE_LINE_SIZE];
1.47
1.48 // The number of cached cards a thread claims when flushing the cache
1.49 static const int ClaimChunkSize = 32;
1.50 @@ -113,16 +122,25 @@
1.51 void reset_hot_cache() {
1.52 assert(SafepointSynchronize::is_at_safepoint(), "Should be at a safepoint");
1.53 assert(Thread::current()->is_VM_thread(), "Current thread should be the VMthread");
1.54 - _hot_cache_idx = 0; _n_hot = 0;
1.55 + if (default_use_cache()) {
1.56 + reset_hot_cache_internal();
1.57 + }
1.58 }
1.59
1.60 - bool hot_cache_is_empty() { return _n_hot == 0; }
1.61 -
1.62 // Zeros the values in the card counts table for entire committed heap
1.63 void reset_card_counts();
1.64
1.65 // Zeros the values in the card counts table for the given region
1.66 void reset_card_counts(HeapRegion* hr);
1.67 +
1.68 + private:
1.69 + void reset_hot_cache_internal() {
1.70 + assert(_hot_cache != NULL, "Logic");
1.71 + _hot_cache_idx = 0;
1.72 + for (size_t i = 0; i < _hot_cache_size; i++) {
1.73 + _hot_cache[i] = NULL;
1.74 + }
1.75 + }
1.76 };
1.77
1.78 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP
