1 /* 2 * Copyright (c) 2018, Red Hat, Inc. All rights reserved. 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 26 #include "gc/shenandoah/heuristics/shenandoahStaticHeuristics.hpp" 27 #include "gc/shenandoah/shenandoahCollectionSet.hpp" 28 #include "gc/shenandoah/shenandoahFreeSet.hpp" 29 #include "gc/shenandoah/shenandoahHeapRegion.hpp" 30 #include "logging/log.hpp" 31 #include "logging/logTag.hpp" 32 33 ShenandoahStaticHeuristics::ShenandoahStaticHeuristics() : ShenandoahHeuristics() { 34 // Static heuristics may degrade to continuous if live data is larger 35 // than free threshold. ShenandoahAllocationThreshold is supposed to break this, 36 // but it only works if it is non-zero. 37 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahAllocationThreshold, 1); 38 39 SHENANDOAH_ERGO_ENABLE_FLAG(ExplicitGCInvokesConcurrent); 40 SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahImplicitGCInvokesConcurrent); 41 42 // Final configuration checks 43 SHENANDOAH_CHECK_FLAG_SET(ShenandoahLoadRefBarrier); 44 SHENANDOAH_CHECK_FLAG_SET(ShenandoahSATBBarrier); 45 SHENANDOAH_CHECK_FLAG_SET(ShenandoahKeepAliveBarrier); 46 SHENANDOAH_CHECK_FLAG_SET(ShenandoahCASBarrier); 47 SHENANDOAH_CHECK_FLAG_SET(ShenandoahCloneBarrier); 48 } 49 50 ShenandoahStaticHeuristics::~ShenandoahStaticHeuristics() {} 51 52 bool ShenandoahStaticHeuristics::should_start_normal_gc() const { 53 ShenandoahHeap* heap = ShenandoahHeap::heap(); 54 55 size_t capacity = heap->capacity(); 56 size_t available = heap->free_set()->available(); 57 size_t threshold_available = (capacity * ShenandoahFreeThreshold) / 100; 58 59 if (available < threshold_available) { 60 log_info(gc)("Trigger: Free (" SIZE_FORMAT "M) is below free threshold (" SIZE_FORMAT "M)", 61 available / M, threshold_available / M); 62 return true; 63 } 64 return ShenandoahHeuristics::should_start_normal_gc(); 65 } 66 67 void ShenandoahStaticHeuristics::choose_collection_set_from_regiondata(ShenandoahCollectionSet* cset, 68 RegionData* data, size_t size, 69 size_t free) { 70 size_t threshold = ShenandoahHeapRegion::region_size_bytes() * ShenandoahGarbageThreshold / 100; 71 72 for (size_t idx = 0; idx < size; idx++) { 73 ShenandoahHeapRegion* r = data[idx]._region; 74 if (r->garbage() > threshold) { 75 cset->add_region(r); 76 } 77 } 78 } 79 80 const char* ShenandoahStaticHeuristics::name() { 81 return "static"; 82 } 83 84 bool ShenandoahStaticHeuristics::is_diagnostic() { 85 return false; 86 } 87 88 bool ShenandoahStaticHeuristics::is_experimental() { 89 return false; 90 }