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/fullGCForwarding.hpp" 30 #include "gc/shared/gcArguments.hpp" 31 #include "gc/shared/genArguments.hpp" 32 #include "gc/shared/workerPolicy.hpp" 33 #include "logging/log.hpp" 34 #include "runtime/globals.hpp" 35 #include "runtime/globals_extension.hpp" 36 #include "runtime/java.hpp" 37 #include "utilities/defaultStream.hpp" 38 #include "utilities/powerOfTwo.hpp" 39 40 size_t ParallelArguments::conservative_max_heap_alignment() { 41 return compute_heap_alignment(); 42 } 43 44 void ParallelArguments::initialize() { 45 GCArguments::initialize(); 46 assert(UseParallelGC, "Error"); 47 48 // If no heap maximum was requested explicitly, use some reasonable fraction 49 // of the physical memory, up to a maximum of 1GB. 50 FLAG_SET_DEFAULT(ParallelGCThreads, 51 WorkerPolicy::parallel_worker_threads()); 52 if (ParallelGCThreads == 0) { 53 jio_fprintf(defaultStream::error_stream(), 54 "The Parallel GC can not be combined with -XX:ParallelGCThreads=0\n"); 55 vm_exit(1); 56 } 57 58 if (UseAdaptiveSizePolicy) { 59 // We don't want to limit adaptive heap sizing's freedom to adjust the heap 60 // unless the user actually sets these flags. 61 if (FLAG_IS_DEFAULT(MinHeapFreeRatio)) { 62 FLAG_SET_DEFAULT(MinHeapFreeRatio, 0); 63 } 64 if (FLAG_IS_DEFAULT(MaxHeapFreeRatio)) { 65 FLAG_SET_DEFAULT(MaxHeapFreeRatio, 100); 66 } 67 } 68 69 // If InitialSurvivorRatio or MinSurvivorRatio were not specified, but the 70 // SurvivorRatio has been set, reset their default values to SurvivorRatio + 71 // 2. By doing this we make SurvivorRatio also work for Parallel Scavenger. 72 // See CR 6362902 for details. 73 if (!FLAG_IS_DEFAULT(SurvivorRatio)) { 74 if (FLAG_IS_DEFAULT(InitialSurvivorRatio)) { 75 FLAG_SET_DEFAULT(InitialSurvivorRatio, SurvivorRatio + 2); 76 } 77 if (FLAG_IS_DEFAULT(MinSurvivorRatio)) { 78 FLAG_SET_DEFAULT(MinSurvivorRatio, SurvivorRatio + 2); 79 } 80 } 81 82 if (FLAG_IS_DEFAULT(ParallelRefProcEnabled) && ParallelGCThreads > 1) { 83 FLAG_SET_DEFAULT(ParallelRefProcEnabled, true); 84 } 85 86 FullGCForwarding::initialize_flags(heap_reserved_size_bytes()); 87 } 88 89 // The alignment used for boundary between young gen and old gen 90 static size_t default_gen_alignment() { 91 return 64 * K * HeapWordSize; 92 } 93 94 void ParallelArguments::initialize_alignments() { 95 // Initialize card size before initializing alignments 96 CardTable::initialize_card_size(); 97 SpaceAlignment = GenAlignment = default_gen_alignment(); 98 HeapAlignment = compute_heap_alignment(); 99 } 100 101 void ParallelArguments::initialize_heap_flags_and_sizes_one_pass() { 102 // Do basic sizing work 103 GenArguments::initialize_heap_flags_and_sizes(); 104 105 // The survivor ratio's are calculated "raw", unlike the 106 // default gc, which adds 2 to the ratio value. We need to 107 // make sure the values are valid before using them. 108 if (MinSurvivorRatio < 3) { 109 FLAG_SET_ERGO(MinSurvivorRatio, 3); 110 } 111 112 if (InitialSurvivorRatio < 3) { 113 FLAG_SET_ERGO(InitialSurvivorRatio, 3); 114 } 115 } 116 117 void ParallelArguments::initialize_heap_flags_and_sizes() { 118 initialize_heap_flags_and_sizes_one_pass(); 119 120 const size_t min_pages = 4; // 1 for eden + 1 for each survivor + 1 for old 121 const size_t page_sz = os::page_size_for_region_aligned(MinHeapSize, min_pages); 122 123 // Can a page size be something else than a power of two? 124 assert(is_power_of_2((intptr_t)page_sz), "must be a power of 2"); 125 size_t new_alignment = align_up(page_sz, GenAlignment); 126 if (new_alignment != GenAlignment) { 127 GenAlignment = new_alignment; 128 SpaceAlignment = new_alignment; 129 // Redo everything from the start 130 initialize_heap_flags_and_sizes_one_pass(); 131 } 132 } 133 134 size_t ParallelArguments::heap_reserved_size_bytes() { 135 return MaxHeapSize; 136 } 137 138 CollectedHeap* ParallelArguments::create_heap() { 139 return new ParallelScavengeHeap(); 140 }