1 /* 2 * Copyright (c) 2020, Oracle and/or its affiliates. All rights reserved. 3 * Copyright (c) 2020 SAP SE. All rights reserved. 4 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 5 * 6 * This code is free software; you can redistribute it and/or modify it 7 * under the terms of the GNU General Public License version 2 only, as 8 * published by the Free Software Foundation. 9 * 10 * This code is distributed in the hope that it will be useful, but WITHOUT 11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 13 * version 2 for more details (a copy is included in the LICENSE file that 14 * accompanied this code). 15 * 16 * You should have received a copy of the GNU General Public License version 17 * 2 along with this work; if not, write to the Free Software Foundation, 18 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 19 * 20 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 21 * or visit www.oracle.com if you need additional information or have any 22 * questions. 23 * 24 */ 25 26 #ifndef SHARE_MEMORY_METASPACE_CHUNKALLOCSEQUENCE_HPP 27 #define SHARE_MEMORY_METASPACE_CHUNKALLOCSEQUENCE_HPP 28 29 #include "memory/metaspace.hpp" // For Metaspace::MetaspaceType 30 #include "memory/metaspace/chunkLevel.hpp" 31 #include "utilities/debug.hpp" 32 33 namespace metaspace { 34 35 36 // ArenaGrowthPolicy encodes the growth policy of a MetaspaceArena. 37 // 38 // These arenas grow in steps (by allocating new chunks). The coarseness of growth 39 // (chunk size, level) depends on what the arena is used for. Used for a class loader 40 // which is expected to load only one or very few classes should grow in tiny steps. 41 // For normal classloaders, it can grow in coarser steps, and arenas used by 42 // the boot loader will grow in even larger steps since we expect it to load a lot of 43 // classes. 44 // Note that when growing in large steps (in steps larger than a commit granule, 45 // by default 64K), costs diminish somewhat since we do not commit the whole space 46 // immediately. 47 48 class ArenaGrowthPolicy { 49 50 // const array specifying chunk level allocation progression (growth steps). Last 51 // chunk is to be an endlessly repeated allocation. 52 const chunklevel_t* const _entries; 53 const int _num_entries; 54 55 ArenaGrowthPolicy(const chunklevel_t* array, int num_entries) 56 : _entries(array), _num_entries(num_entries) { 57 assert(_num_entries > 0, "must not be empty."); 58 } 59 60 public: 61 62 chunklevel_t get_level_at_step(int num_allocated) const { 63 if (num_allocated >= _num_entries) { 64 // Caller shall repeat last allocation 65 return _entries[_num_entries - 1]; 66 } 67 return _entries[num_allocated]; 68 } 69 70 // Given a space type, return the correct policy to use. 71 // The returned object is static and read only. 72 static const ArenaGrowthPolicy* policy_for_space_type(Metaspace::MetaspaceType space_type, bool is_class); 73 74 }; 75 76 77 } // namespace metaspace 78 79 #endif // SHARE_MEMORY_METASPACE_CHUNKALLOCSEQUENCE_HPP