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/shenandoahStaticHeuristics.hpp" 26 #include "gc_implementation/shenandoah/shenandoahCollectionSet.hpp" 27 #include "gc_implementation/shenandoah/shenandoahFreeSet.hpp" 28 #include "gc_implementation/shenandoah/shenandoahHeapRegion.hpp" 29 #include "gc_implementation/shenandoah/shenandoahLogging.hpp" 30 31 ShenandoahStaticHeuristics::ShenandoahStaticHeuristics() : ShenandoahHeuristics() { 32 // Static heuristics may degrade to continuous if live data is larger 33 // than free threshold. ShenandoahAllocationThreshold is supposed to break this, 34 // but it only works if it is non-zero. 35 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahImmediateThreshold, 1); 36 } 37 38 ShenandoahStaticHeuristics::~ShenandoahStaticHeuristics() {} 39 40 bool ShenandoahStaticHeuristics::should_start_normal_gc() const { 41 ShenandoahHeap* heap = ShenandoahHeap::heap(); 42 43 size_t capacity = heap->capacity(); 44 size_t available = heap->free_set()->available(); 45 size_t threshold_available = (capacity * ShenandoahFreeThreshold) / 100; 46 47 if (available < threshold_available) { 48 log_info(gc)("Trigger: Free (" SIZE_FORMAT "M) is below free threshold (" SIZE_FORMAT "M)", 49 available / M, threshold_available / M); 50 return true; 51 } 52 return ShenandoahHeuristics::should_start_normal_gc(); 53 } 54 55 void ShenandoahStaticHeuristics::choose_collection_set_from_regiondata(ShenandoahCollectionSet* cset, 56 RegionData* data, size_t size, 57 size_t free) { 58 size_t threshold = ShenandoahHeapRegion::region_size_bytes() * ShenandoahGarbageThreshold / 100; 59 60 for (size_t idx = 0; idx < size; idx++) { 61 ShenandoahHeapRegion* r = data[idx]._region; 62 if (r->garbage() > threshold) { 63 cset->add_region(r); 64 } 65 } 66 } 67 68 const char* ShenandoahStaticHeuristics::name() { 69 return "static"; 70 } 71 72 bool ShenandoahStaticHeuristics::is_diagnostic() { 73 return false; 74 } 75 76 bool ShenandoahStaticHeuristics::is_experimental() { 77 return false; 78 }