1 /* 2 * Copyright (c) 2018, 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 "precompiled.hpp" 27 #include "gc/shared/gcArguments.hpp" 28 #include "runtime/arguments.hpp" 29 #include "runtime/globals.hpp" 30 #include "runtime/globals_extension.hpp" 31 #include "utilities/macros.hpp" 32 33 void GCArguments::initialize() { 34 if (FullGCALot && FLAG_IS_DEFAULT(MarkSweepAlwaysCompactCount)) { 35 MarkSweepAlwaysCompactCount = 1; // Move objects every gc. 36 } 37 38 if (!(UseParallelGC || UseParallelOldGC) && FLAG_IS_DEFAULT(ScavengeBeforeFullGC)) { 39 FLAG_SET_DEFAULT(ScavengeBeforeFullGC, false); 40 } 41 42 if (GCTimeLimit == 100) { 43 // Turn off gc-overhead-limit-exceeded checks 44 FLAG_SET_DEFAULT(UseGCOverheadLimit, false); 45 } 46 47 if (MinHeapFreeRatio == 100) { 48 // Keeping the heap 100% free is hard ;-) so limit it to 99%. 49 FLAG_SET_ERGO(uintx, MinHeapFreeRatio, 99); 50 } 51 52 if (!ClassUnloading) { 53 // If class unloading is disabled, also disable concurrent class unloading. 54 FLAG_SET_CMDLINE(bool, ClassUnloadingWithConcurrentMark, false); 55 } 56 }