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 38 void ShenandoahAggressiveHeuristics::choose_collection_set_from_regiondata(ShenandoahCollectionSet* cset, 39 RegionData* data, size_t size, 40 size_t free) { 41 for (size_t idx = 0; idx < size; idx++) { 42 ShenandoahHeapRegion* r = data[idx]._region; 43 if (r->garbage() > 0) { 44 cset->add_region(r); 45 } 46 } 47 } 48 49 bool ShenandoahAggressiveHeuristics::should_start_normal_gc() const { 50 return true; 51 } 52 53 bool ShenandoahAggressiveHeuristics::should_process_references() { 54 if (ShenandoahRefProcFrequency == 0) return false; 55 // Randomly process refs with 50% chance. 56 return (os::random() & 1) == 1; 57 } 58 59 bool ShenandoahAggressiveHeuristics::should_unload_classes() { 60 if (ShenandoahUnloadClassesFrequency == 0) return false; 61 // Randomly unload classes with 50% chance. 62 return (os::random() & 1) == 1; 63 } 64 65 const char* ShenandoahAggressiveHeuristics::name() { 66 return "aggressive"; 67 } 68 69 bool ShenandoahAggressiveHeuristics::is_diagnostic() { 70 return true; 71 } 72 73 bool ShenandoahAggressiveHeuristics::is_experimental() { 74 return false; 75 }