1 /* 2 * Copyright (c) 2018, 2019, Red Hat, Inc. All rights reserved. 3 * Copyright Amazon.com Inc. or its affiliates. All Rights Reserved. 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 28 #include "gc/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp" 29 #include "gc/shenandoah/shenandoahCollectionSet.hpp" 30 #include "gc/shenandoah/shenandoahHeapRegion.inline.hpp" 31 #include "logging/log.hpp" 32 #include "logging/logTag.hpp" 33 #include "runtime/os.hpp" 34 35 ShenandoahAggressiveHeuristics::ShenandoahAggressiveHeuristics(ShenandoahSpaceInfo* space_info) : 36 ShenandoahHeuristics(space_info) { 37 // Do not shortcut evacuation 38 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahImmediateThreshold, 100); 39 40 // Aggressive evacuates everything, so it needs as much evac space as it can get 41 SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahEvacReserveOverflow); 42 } 43 44 void ShenandoahAggressiveHeuristics::choose_collection_set_from_regiondata(ShenandoahCollectionSet* cset, 45 RegionData* data, size_t size, 46 size_t free) { 47 for (size_t idx = 0; idx < size; idx++) { 48 ShenandoahHeapRegion* r = data[idx]._region; 49 if (r->garbage() > 0) { 50 cset->add_region(r); 51 } 52 } 53 } 54 55 bool ShenandoahAggressiveHeuristics::should_start_gc() { 56 log_info(gc)("Trigger: Start next cycle immediately"); 57 return true; 58 } 59 60 bool ShenandoahAggressiveHeuristics::should_unload_classes() { 61 if (!can_unload_classes()) return false; 62 if (has_metaspace_oom()) return true; 63 // Randomly unload classes with 50% chance. 64 return (os::random() & 1) == 1; 65 }