1/* 2 * Copyright (c) 2013, 2016, Oracle and/or its affiliates. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25#ifndef SHARE_VM_GC_G1_G1FROMCARDCACHE_HPP 26#define SHARE_VM_GC_G1_G1FROMCARDCACHE_HPP 27 28#include "memory/allocation.hpp" 29#include "utilities/ostream.hpp" 30 31// G1FromCardCache remembers the most recently processed card on the heap on 32// a per-region and per-thread basis. 33class G1FromCardCache : public AllStatic { 34 private: 35 // Array of card indices. Indexed by heap region (rows) and thread (columns) to minimize 36 // thread contention. 37 // This order minimizes the time to clear all entries for a given region during region 38 // freeing. I.e. a single clear of a single memory area instead of multiple separate 39 // accesses with a large stride per region. 40 static int** _cache; 41 static uint _max_regions; 42 static size_t _static_mem_size; 43 44 public: 45 enum { 46 InvalidCard = -1 // Card value of an invalid card, i.e. a card index not otherwise used. 47 }; 48 49 static void clear(uint region_idx); 50 51 // Returns true if the given card is in the cache at the given location, or 52 // replaces the card at that location and returns false. 53 static bool contains_or_replace(uint worker_id, uint region_idx, int card) { 54 int card_in_cache = at(worker_id, region_idx); 55 if (card_in_cache == card) { 56 return true; 57 } else { 58 set(worker_id, region_idx, card); 59 return false; 60 } 61 } 62 63 static int at(uint worker_id, uint region_idx) { 64 return _cache[region_idx][worker_id]; 65 } 66 67 static void set(uint worker_id, uint region_idx, int val) { 68 _cache[region_idx][worker_id] = val; 69 } 70 71 static void initialize(uint num_par_rem_sets, uint max_num_regions); 72 73 static void invalidate(uint start_idx, size_t num_regions); 74 75 static void print(outputStream* out = tty) PRODUCT_RETURN; 76 77 static size_t static_mem_size() { 78 return _static_mem_size; 79 } 80}; 81 82#endif // SHARE_VM_GC_G1_G1FROMCARDCACHE_HPP 83