1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/gc_implementation/g1/g1HotCardCache.hpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,128 @@
1.4 +/*
1.5 + * Copyright (c) 2013, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP
1.29 +#define SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP
1.30 +
1.31 +#include "gc_implementation/g1/g1_globals.hpp"
1.32 +#include "gc_implementation/g1/g1CardCounts.hpp"
1.33 +#include "memory/allocation.hpp"
1.34 +#include "runtime/safepoint.hpp"
1.35 +#include "runtime/thread.inline.hpp"
1.36 +#include "utilities/globalDefinitions.hpp"
1.37 +
1.38 +class DirtyCardQueue;
1.39 +class G1CollectedHeap;
1.40 +class G1RemSet;
1.41 +class HeapRegion;
1.42 +
1.43 +// An evicting cache of cards that have been logged by the G1 post
1.44 +// write barrier. Placing a card in the cache delays the refinement
1.45 +// of the card until the card is evicted, or the cache is drained
1.46 +// during the next evacuation pause.
1.47 +//
1.48 +// The first thing the G1 post write barrier does is to check whether
1.49 +// the card containing the updated pointer is already dirty and, if
1.50 +// so, skips the remaining code in the barrier.
1.51 +//
1.52 +// Delaying the refinement of a card will make the card fail the
1.53 +// first is_dirty check in the write barrier, skipping the remainder
1.54 +// of the write barrier.
1.55 +//
1.56 +// This can significantly reduce the overhead of the write barrier
1.57 +// code, increasing throughput.
1.58 +
1.59 +class G1HotCardCache: public CHeapObj<mtGC> {
1.60 + G1CollectedHeap* _g1h;
1.61 +
1.62 + // The card cache table
1.63 + jbyte** _hot_cache;
1.64 +
1.65 + int _hot_cache_size;
1.66 + int _n_hot;
1.67 + int _hot_cache_idx;
1.68 +
1.69 + int _hot_cache_par_chunk_size;
1.70 + volatile int _hot_cache_par_claimed_idx;
1.71 +
1.72 + bool _use_cache;
1.73 +
1.74 + G1CardCounts _card_counts;
1.75 +
1.76 + bool default_use_cache() const {
1.77 + return (G1ConcRSLogCacheSize > 0);
1.78 + }
1.79 +
1.80 + public:
1.81 + G1HotCardCache(G1CollectedHeap* g1h);
1.82 + ~G1HotCardCache();
1.83 +
1.84 + void initialize();
1.85 +
1.86 + bool use_cache() { return _use_cache; }
1.87 +
1.88 + void set_use_cache(bool b) {
1.89 + _use_cache = (b ? default_use_cache() : false);
1.90 + }
1.91 +
1.92 + // Returns the card to be refined or NULL.
1.93 + //
1.94 + // Increments the count for given the card. if the card is not 'hot',
1.95 + // it is returned for immediate refining. Otherwise the card is
1.96 + // added to the hot card cache.
1.97 + // If there is enough room in the hot card cache for the card we're
1.98 + // adding, NULL is returned and no further action in needed.
1.99 + // If we evict a card from the cache to make room for the new card,
1.100 + // the evicted card is then returned for refinement.
1.101 + jbyte* insert(jbyte* card_ptr);
1.102 +
1.103 + // Refine the cards that have delayed as a result of
1.104 + // being in the cache.
1.105 + void drain(uint worker_i, G1RemSet* g1rs, DirtyCardQueue* into_cset_dcq);
1.106 +
1.107 + // Set up for parallel processing of the cards in the hot cache
1.108 + void reset_hot_cache_claimed_index() {
1.109 + _hot_cache_par_claimed_idx = 0;
1.110 + }
1.111 +
1.112 + // Resets the hot card cache and discards the entries.
1.113 + void reset_hot_cache() {
1.114 + assert(SafepointSynchronize::is_at_safepoint(), "Should be at a safepoint");
1.115 + assert(Thread::current()->is_VM_thread(), "Current thread should be the VMthread");
1.116 + _hot_cache_idx = 0; _n_hot = 0;
1.117 + }
1.118 +
1.119 + bool hot_cache_is_empty() { return _n_hot == 0; }
1.120 +
1.121 + // Resizes the card counts table to match the given capacity
1.122 + void resize_card_counts(size_t heap_capacity);
1.123 +
1.124 + // Zeros the values in the card counts table for entire committed heap
1.125 + void reset_card_counts();
1.126 +
1.127 + // Zeros the values in the card counts table for the given region
1.128 + void reset_card_counts(HeapRegion* hr);
1.129 +};
1.130 +
1.131 +#endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP
