Mercurial > hg > graal-jvmci-8
view src/share/vm/gc_implementation/g1/g1HotCardCache.hpp @ 23287:bd88fd590f4e
Restore G1 changes from e13c65f874e5 after merge
author | Gilles Duboscq <gilles.m.duboscq@oracle.com> |
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date | Fri, 08 Jan 2016 15:46:55 +0100 |
parents | b6a1bf5222c5 |
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/* * Copyright (c) 2013, 2015, Oracle and/or its affiliates. All rights reserved. * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. * * This code is free software; you can redistribute it and/or modify it * under the terms of the GNU General Public License version 2 only, as * published by the Free Software Foundation. * * This code is distributed in the hope that it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License * version 2 for more details (a copy is included in the LICENSE file that * accompanied this code). * * You should have received a copy of the GNU General Public License version * 2 along with this work; if not, write to the Free Software Foundation, * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. * * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA * or visit www.oracle.com if you need additional information or have any * questions. * */ #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP #define SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP #include "gc_implementation/g1/g1_globals.hpp" #include "gc_implementation/g1/g1CardCounts.hpp" #include "memory/allocation.hpp" #include "runtime/safepoint.hpp" #include "runtime/thread.inline.hpp" #include "utilities/globalDefinitions.hpp" class DirtyCardQueue; class G1CollectedHeap; class G1RemSet; class HeapRegion; // An evicting cache of cards that have been logged by the G1 post // write barrier. Placing a card in the cache delays the refinement // of the card until the card is evicted, or the cache is drained // during the next evacuation pause. // // The first thing the G1 post write barrier does is to check whether // the card containing the updated pointer is already dirty and, if // so, skips the remaining code in the barrier. // // Delaying the refinement of a card will make the card fail the // first is_dirty check in the write barrier, skipping the remainder // of the write barrier. // // This can significantly reduce the overhead of the write barrier // code, increasing throughput. class G1HotCardCache: public CHeapObj<mtGC> { G1CollectedHeap* _g1h; bool _use_cache; G1CardCounts _card_counts; // The card cache table jbyte** _hot_cache; size_t _hot_cache_size; int _hot_cache_par_chunk_size; // Avoids false sharing when concurrently updating _hot_cache_idx or // _hot_cache_par_claimed_idx. These are never updated at the same time // thus it's not necessary to separate them as well char _pad_before[DEFAULT_CACHE_LINE_SIZE]; volatile size_t _hot_cache_idx; volatile size_t _hot_cache_par_claimed_idx; char _pad_after[DEFAULT_CACHE_LINE_SIZE]; // The number of cached cards a thread claims when flushing the cache static const int ClaimChunkSize = 32; bool default_use_cache() const { return (G1ConcRSLogCacheSize > 0); } public: G1HotCardCache(G1CollectedHeap* g1h); ~G1HotCardCache(); void initialize(G1RegionToSpaceMapper* card_counts_storage); bool use_cache() { return _use_cache; } void set_use_cache(bool b) { _use_cache = (b ? default_use_cache() : false); } // Returns the card to be refined or NULL. // // Increments the count for given the card. if the card is not 'hot', // it is returned for immediate refining. Otherwise the card is // added to the hot card cache. // If there is enough room in the hot card cache for the card we're // adding, NULL is returned and no further action in needed. // If we evict a card from the cache to make room for the new card, // the evicted card is then returned for refinement. jbyte* insert(jbyte* card_ptr); // Refine the cards that have delayed as a result of // being in the cache. void drain(uint worker_i, G1RemSet* g1rs, DirtyCardQueue* into_cset_dcq); // Set up for parallel processing of the cards in the hot cache void reset_hot_cache_claimed_index() { _hot_cache_par_claimed_idx = 0; } // Resets the hot card cache and discards the entries. void reset_hot_cache() { assert(SafepointSynchronize::is_at_safepoint(), "Should be at a safepoint"); assert(Thread::current()->is_VM_thread(), "Current thread should be the VMthread"); if (default_use_cache()) { reset_hot_cache_internal(); } } // Zeros the values in the card counts table for entire committed heap void reset_card_counts(); // Zeros the values in the card counts table for the given region void reset_card_counts(HeapRegion* hr); private: void reset_hot_cache_internal() { assert(_hot_cache != NULL, "Logic"); _hot_cache_idx = 0; for (size_t i = 0; i < _hot_cache_size; i++) { _hot_cache[i] = NULL; } } }; #endif // SHARE_VM_GC_IMPLEMENTATION_G1_G1HOTCARDCACHE_HPP