1 /* 2 * Copyright (c) 2017, Red Hat, Inc. and/or its affiliates. 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 #include "precompiled.hpp" 26 #include "gc/parallel/parallelArguments.hpp" 27 #include "gc/shared/collectorPolicy.hpp" 28 #include "runtime/globals.hpp" 29 #include "runtime/globals_extension.hpp" 30 #include "runtime/java.hpp" 31 #include "runtime/vm_version.hpp" 32 #include "utilities/defaultStream.hpp" 33 34 size_t ParallelArguments::conservative_max_heap_alignment() { 35 return CollectorPolicy::compute_heap_alignment(); 36 } 37 38 void ParallelArguments::initialize_flags() { 39 GCArguments::initialize_flags(); 40 assert(UseParallelGC || UseParallelOldGC, "Error"); 41 // Enable ParallelOld unless it was explicitly disabled (cmd line or rc file). 42 if (FLAG_IS_DEFAULT(UseParallelOldGC)) { 43 FLAG_SET_DEFAULT(UseParallelOldGC, true); 44 } 45 FLAG_SET_DEFAULT(UseParallelGC, true); 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 Abstract_VM_Version::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 or MinSurvivorRatio were not specified, but the 69 // SurvivorRatio has been set, reset their default values to SurvivorRatio + 70 // 2. By doing this we make SurvivorRatio also work for Parallel Scavenger. 71 // See CR 6362902 for details. 72 if (!FLAG_IS_DEFAULT(SurvivorRatio)) { 73 if (FLAG_IS_DEFAULT(InitialSurvivorRatio)) { 74 FLAG_SET_DEFAULT(InitialSurvivorRatio, SurvivorRatio + 2); 75 } 76 if (FLAG_IS_DEFAULT(MinSurvivorRatio)) { 77 FLAG_SET_DEFAULT(MinSurvivorRatio, SurvivorRatio + 2); 78 } 79 } 80 81 if (UseParallelOldGC) { 82 // Par compact uses lower default values since they are treated as 83 // minimums. These are different defaults because of the different 84 // interpretation and are not ergonomically set. 85 if (FLAG_IS_DEFAULT(MarkSweepDeadRatio)) { 86 FLAG_SET_DEFAULT(MarkSweepDeadRatio, 1); 87 } 88 } 89 }