1 /* 2 * Copyright (c) 2018, Red Hat, Inc. and/or its affiliates. 3 * 4 * This code is free software; you can redistribute it and/or modify it 5 * under the terms of the GNU General Public License version 2 only, as 6 * published by the Free Software Foundation. 7 * 8 * This code is distributed in the hope that it will be useful, but WITHOUT 9 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 10 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 11 * version 2 for more details (a copy is included in the LICENSE file that 12 * accompanied this code). 13 * 14 * You should have received a copy of the GNU General Public License version 15 * 2 along with this work; if not, write to the Free Software Foundation, 16 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 17 * 18 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 19 * or visit www.oracle.com if you need additional information or have any 20 * questions. 21 * 22 */ 23 24 #include "precompiled.hpp" 25 #include "gc_implementation/shenandoah/heuristics/shenandoahAggressiveHeuristics.hpp" 26 #include "gc_implementation/shenandoah/shenandoahCollectionSet.hpp" 27 #include "gc_implementation/shenandoah/shenandoahHeapRegion.hpp" 28 #include "gc_implementation/shenandoah/shenandoahLogging.hpp" 29 30 ShenandoahAggressiveHeuristics::ShenandoahAggressiveHeuristics() : ShenandoahHeuristics() { 31 // Do not shortcut evacuation 32 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahImmediateThreshold, 100); 33 34 // Aggressive runs with max speed for allocation, to capture races against mutator 35 SHENANDOAH_ERGO_DISABLE_FLAG(ShenandoahPacing); 36 37 // Aggressive evacuates everything, so it needs as much evac space as it can get 38 SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahEvacReserveOverflow); 39 40 // If class unloading is globally enabled, aggressive does unloading even with 41 // concurrent cycles. 42 if (ClassUnloading) { 43 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahUnloadClassesFrequency, 1); 44 } 45 } 46 47 void ShenandoahAggressiveHeuristics::choose_collection_set_from_regiondata(ShenandoahCollectionSet* cset, 48 RegionData* data, size_t size, 49 size_t free) { 50 for (size_t idx = 0; idx < size; idx++) { 51 ShenandoahHeapRegion* r = data[idx]._region; 52 if (r->garbage() > 0) { 53 cset->add_region(r); 54 } 55 } 56 } 57 58 bool ShenandoahAggressiveHeuristics::should_start_normal_gc() const { 59 log_info(gc)("Trigger: Start next cycle immediately"); 60 return true; 61 } 62 63 bool ShenandoahAggressiveHeuristics::should_process_references() { 64 if (ShenandoahRefProcFrequency == 0) return false; 65 // Randomly process refs with 50% chance. 66 return (os::random() & 1) == 1; 67 } 68 69 bool ShenandoahAggressiveHeuristics::should_unload_classes() { 70 if (ShenandoahUnloadClassesFrequency == 0) return false; 71 // Randomly unload classes with 50% chance. 72 return (os::random() & 1) == 1; 73 } 74 75 const char* ShenandoahAggressiveHeuristics::name() { 76 return "aggressive"; 77 } 78 79 bool ShenandoahAggressiveHeuristics::is_diagnostic() { 80 return true; 81 } 82 83 bool ShenandoahAggressiveHeuristics::is_experimental() { 84 return false; 85 }