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. 33 class 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 uintptr_t** _cache; 41 static uint _max_regions; 42 static size_t _static_mem_size; 43 #ifdef ASSERT 44 static uint _max_workers; 45 46 static void check_bounds(uint worker_id, uint region_idx) { 47 assert(worker_id < _max_workers, "Worker_id %u is larger than maximum %u", worker_id, _max_workers); 48 assert(region_idx < _max_regions, "Region_idx %u is larger than maximum %u", region_idx, _max_regions); 49 } 50 #endif 51 52 public: 53 static const uintptr_t InvalidCard = UINTPTR_MAX; 54 55 static void clear(uint region_idx); 56 57 // Returns true if the given card is in the cache at the given location, or 58 // replaces the card at that location and returns false. 59 static bool contains_or_replace(uint worker_id, uint region_idx, uintptr_t card) { 60 uintptr_t card_in_cache = at(worker_id, region_idx); 61 if (card_in_cache == card) { 62 return true; 63 } else { 64 set(worker_id, region_idx, card); 65 return false; 66 } 67 } 68 69 static uintptr_t at(uint worker_id, uint region_idx) { 70 DEBUG_ONLY(check_bounds(worker_id, region_idx);) 71 return _cache[region_idx][worker_id]; 72 } 73 74 static void set(uint worker_id, uint region_idx, uintptr_t val) { 75 DEBUG_ONLY(check_bounds(worker_id, region_idx);) 76 _cache[region_idx][worker_id] = val; 77 } 78 79 static void initialize(uint num_par_rem_sets, uint max_num_regions); 80 81 static void invalidate(uint start_idx, size_t num_regions); 82 83 static void print(outputStream* out = tty) PRODUCT_RETURN; 84 85 static size_t static_mem_size() { 86 return _static_mem_size; 87 } 88 }; 89 90 #endif // SHARE_VM_GC_G1_G1FROMCARDCACHE_HPP