1 /* 2 * Copyright (c) 2018, 2019, Red Hat, Inc. All rights reserved. 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 27 #include "gc/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp" 28 #include "gc/shenandoah/shenandoahCollectionSet.hpp" 29 #include "gc/shenandoah/shenandoahHeapRegion.hpp" 30 #include "logging/log.hpp" 31 #include "logging/logTag.hpp" 32 #include "runtime/os.hpp" 33 34 ShenandoahAggressiveHeuristics::ShenandoahAggressiveHeuristics() : ShenandoahHeuristics() { 35 // Do not shortcut evacuation 36 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahImmediateThreshold, 100); 37 38 // Aggressive evacuates everything, so it needs as much evac space as it can get 39 SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahEvacReserveOverflow); 40 41 // If class unloading is globally enabled, aggressive does unloading even with 42 // concurrent cycles. 43 if (ClassUnloading) { 44 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahUnloadClassesFrequency, 1); 45 } 46 47 // Final configuration checks 48 SHENANDOAH_CHECK_FLAG_SET(ShenandoahLoadRefBarrier); 49 SHENANDOAH_CHECK_FLAG_SET(ShenandoahSATBBarrier); 50 SHENANDOAH_CHECK_FLAG_SET(ShenandoahCASBarrier); 51 SHENANDOAH_CHECK_FLAG_SET(ShenandoahCloneBarrier); 52 } 53 54 void ShenandoahAggressiveHeuristics::choose_collection_set_from_regiondata(ShenandoahCollectionSet* cset, 55 RegionData* data, size_t size, 56 size_t free) { 57 for (size_t idx = 0; idx < size; idx++) { 58 ShenandoahHeapRegion* r = data[idx]._region; 59 if (r->garbage() > 0) { 60 cset->add_region(r); 61 } 62 } 63 } 64 65 bool ShenandoahAggressiveHeuristics::should_start_gc() const { 66 log_info(gc)("Trigger: Start next cycle immediately"); 67 return true; 68 } 69 70 bool ShenandoahAggressiveHeuristics::should_process_references() { 71 if (!can_process_references()) return false; 72 // Randomly process refs with 50% chance. 73 return (os::random() & 1) == 1; 74 } 75 76 bool ShenandoahAggressiveHeuristics::should_unload_classes() { 77 if (!can_unload_classes_normal()) return false; 78 if (has_metaspace_oom()) return true; 79 // Randomly unload classes with 50% chance. 80 return (os::random() & 1) == 1; 81 } 82 83 const char* ShenandoahAggressiveHeuristics::name() { 84 return "aggressive"; 85 } 86 87 bool ShenandoahAggressiveHeuristics::is_diagnostic() { 88 return true; 89 } 90 91 bool ShenandoahAggressiveHeuristics::is_experimental() { 92 return false; 93 }