1 /* 2 * Copyright (c) 2018, 2025, Oracle and/or its affiliates. All rights reserved. 3 * Copyright (c) 2017, Red Hat, Inc. and/or its affiliates. 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 #include "gc/parallel/parallelArguments.hpp" 27 #include "gc/parallel/parallelScavengeHeap.hpp" 28 #include "gc/shared/adaptiveSizePolicy.hpp" 29 #include "gc/shared/gcArguments.hpp" 30 #include "gc/shared/genArguments.hpp" 31 #include "gc/shared/workerPolicy.hpp" 32 #include "logging/log.hpp" 33 #include "runtime/globals.hpp" 34 #include "runtime/globals_extension.hpp" 35 #include "runtime/java.hpp" 36 #include "utilities/defaultStream.hpp" 37 #include "utilities/powerOfTwo.hpp" 38 39 size_t ParallelArguments::conservative_max_heap_alignment() { 40 return compute_heap_alignment(); 41 } 42 43 void ParallelArguments::initialize() { 44 GCArguments::initialize(); 45 assert(UseParallelGC, "Error"); 46 47 // If no heap maximum was requested explicitly, use some reasonable fraction 48 // of the physical memory, up to a maximum of 1GB. 49 FLAG_SET_DEFAULT(ParallelGCThreads, 50 WorkerPolicy::parallel_worker_threads()); 51 if (ParallelGCThreads == 0) { 52 jio_fprintf(defaultStream::error_stream(), 53 "The Parallel GC can not be combined with -XX:ParallelGCThreads=0\n"); 54 vm_exit(1); 55 } 56 57 if (UseAdaptiveSizePolicy) { 58 // We don't want to limit adaptive heap sizing's freedom to adjust the heap 59 // unless the user actually sets these flags. 60 if (FLAG_IS_DEFAULT(MinHeapFreeRatio)) { 61 FLAG_SET_DEFAULT(MinHeapFreeRatio, 0); 62 } 63 if (FLAG_IS_DEFAULT(MaxHeapFreeRatio)) { 64 FLAG_SET_DEFAULT(MaxHeapFreeRatio, 100); 65 } 66 } 67 68 if (InitialSurvivorRatio < MinSurvivorRatio) { 69 if (FLAG_IS_CMDLINE(InitialSurvivorRatio)) { 70 if (FLAG_IS_CMDLINE(MinSurvivorRatio)) { 71 jio_fprintf(defaultStream::error_stream(), 72 "Inconsistent MinSurvivorRatio vs InitialSurvivorRatio: %d vs %d\n", MinSurvivorRatio, InitialSurvivorRatio); 73 } 74 FLAG_SET_DEFAULT(MinSurvivorRatio, InitialSurvivorRatio); 75 } else { 76 FLAG_SET_DEFAULT(InitialSurvivorRatio, MinSurvivorRatio); 77 } 78 } 79 80 // If InitialSurvivorRatio or MinSurvivorRatio were not specified, but the 81 // SurvivorRatio has been set, reset their default values to SurvivorRatio + 82 // 2. By doing this we make SurvivorRatio also work for Parallel Scavenger. 83 // See CR 6362902 for details. 84 if (!FLAG_IS_DEFAULT(SurvivorRatio)) { 85 if (FLAG_IS_DEFAULT(InitialSurvivorRatio)) { 86 FLAG_SET_DEFAULT(InitialSurvivorRatio, SurvivorRatio + 2); 87 } 88 if (FLAG_IS_DEFAULT(MinSurvivorRatio)) { 89 FLAG_SET_DEFAULT(MinSurvivorRatio, SurvivorRatio + 2); 90 } 91 } 92 93 if (FLAG_IS_DEFAULT(ParallelRefProcEnabled) && ParallelGCThreads > 1) { 94 FLAG_SET_DEFAULT(ParallelRefProcEnabled, true); 95 } 96 } 97 98 // The alignment used for boundary between young gen and old gen 99 static size_t default_gen_alignment() { 100 return 64 * K * HeapWordSize; 101 } 102 103 void ParallelArguments::initialize_alignments() { 104 // Initialize card size before initializing alignments 105 CardTable::initialize_card_size(); 106 SpaceAlignment = GenAlignment = default_gen_alignment(); 107 HeapAlignment = compute_heap_alignment(); 108 } 109 110 void ParallelArguments::initialize_heap_flags_and_sizes_one_pass() { 111 // Do basic sizing work 112 GenArguments::initialize_heap_flags_and_sizes(); 113 } 114 115 void ParallelArguments::initialize_heap_flags_and_sizes() { 116 initialize_heap_flags_and_sizes_one_pass(); 117 118 const size_t min_pages = 4; // 1 for eden + 1 for each survivor + 1 for old 119 const size_t page_sz = os::page_size_for_region_aligned(MinHeapSize, min_pages); 120 121 // Can a page size be something else than a power of two? 122 assert(is_power_of_2((intptr_t)page_sz), "must be a power of 2"); 123 size_t new_alignment = align_up(page_sz, GenAlignment); 124 if (new_alignment != GenAlignment) { 125 GenAlignment = new_alignment; 126 SpaceAlignment = new_alignment; 127 // Redo everything from the start 128 initialize_heap_flags_and_sizes_one_pass(); 129 } 130 } 131 132 size_t ParallelArguments::heap_reserved_size_bytes() { 133 return MaxHeapSize; 134 } 135 136 CollectedHeap* ParallelArguments::create_heap() { 137 return new ParallelScavengeHeap(); 138 }