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_ALIGNMENT_HPP 27 #define SHARE_MEMORY_METASPACE_ALIGNMENT_HPP 28 29 #include "memory/metaspace/chunklevel.hpp" 30 #include "memory/metaspace/freeBlocks.hpp" 31 #include "utilities/align.hpp" 32 #include "utilities/powerOfTwo.hpp" 33 #include "utilities/globalDefinitions.hpp" 34 35 namespace metaspace { 36 37 // The minimal alignment: good enough to store structures with 64bit wide members (also on 32-bit). 38 // Should we ever store longer values, revise. 39 static const int LogMetaspaceMinimalAlignment = LogBytesPerLong; 40 static const int MetaspaceMinAlignmentBytes = 1 << LogMetaspaceMinimalAlignment; 41 static const int MetaspaceMinAlignmentWords = MetaspaceMinAlignmentBytes / BytesPerWord; 42 43 // The maximum possible alignment is the smallest chunk size (note that the buddy allocator places 44 // chunks at chunk-size-aligned boundaries, therefore the start address is guaranteed to be aligned). 45 // We cannot guarantee allocation alignment beyond this value. 46 static const int MetaspaceMaxAlignmentWords = chunklevel::MIN_CHUNK_WORD_SIZE; 47 48 // Given a net allocation word size and an alignment value, return the raw word size we actually 49 // allocate internally. 50 inline size_t get_raw_word_size_for_requested_word_size(size_t net_word_size, 51 size_t alignment_words) { 52 53 // The alignment should be between the minimum alignment but cannot be larger than the smallest chunk size 54 assert(is_power_of_2(alignment_words), "invalid alignment"); 55 assert(alignment_words >= MetaspaceMinAlignmentWords && 56 alignment_words <= MetaspaceMaxAlignmentWords, 57 "invalid alignment (" SIZE_FORMAT ")", alignment_words); 58 59 // Deallocated metablocks are kept in a binlist which means blocks need to have 60 // a minimal size 61 size_t raw_word_size = MAX2(net_word_size, FreeBlocks::MinWordSize); 62 63 raw_word_size = align_up(raw_word_size, alignment_words); 64 65 return raw_word_size; 66 } 67 68 } // namespace metaspace 69 70 #endif // SHARE_MEMORY_METASPACE_ALIGNMENT_HPP