1 /* 2 * Copyright (c) 2018, 2019, Red Hat, Inc. All rights reserved. 3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. 4 * 5 * This code is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2 only, as 7 * published by the Free Software Foundation. 8 * 9 * This code is distributed in the hope that it will be useful, but WITHOUT 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or 11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License 12 * version 2 for more details (a copy is included in the LICENSE file that 13 * accompanied this code). 14 * 15 * You should have received a copy of the GNU General Public License version 16 * 2 along with this work; if not, write to the Free Software Foundation, 17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. 18 * 19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA 20 * or visit www.oracle.com if you need additional information or have any 21 * questions. 22 * 23 */ 24 25 #include "precompiled.hpp" 26 27 #include "gc/shenandoah/shenandoahCollectionSet.hpp" 28 #include "gc/shenandoah/heuristics/shenandoahCompactHeuristics.hpp" 29 #include "gc/shenandoah/shenandoahFreeSet.hpp" 30 #include "gc/shenandoah/shenandoahHeapRegion.hpp" 31 #include "logging/log.hpp" 32 #include "logging/logTag.hpp" 33 34 ShenandoahCompactHeuristics::ShenandoahCompactHeuristics() : ShenandoahHeuristics() { 35 SHENANDOAH_ERGO_ENABLE_FLAG(ExplicitGCInvokesConcurrent); 36 SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahImplicitGCInvokesConcurrent); 37 SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahUncommit); 38 SHENANDOAH_ERGO_ENABLE_FLAG(ShenandoahAlwaysClearSoftRefs); 39 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahAllocationThreshold, 10); 40 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahImmediateThreshold, 100); 41 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahUncommitDelay, 1000); 42 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahGuaranteedGCInterval, 30000); 43 SHENANDOAH_ERGO_OVERRIDE_DEFAULT(ShenandoahGarbageThreshold, 10); 44 } 45 46 bool ShenandoahCompactHeuristics::should_start_gc() const { 47 ShenandoahHeap* heap = ShenandoahHeap::heap(); 48 49 size_t capacity = heap->max_capacity(); 50 size_t available = heap->free_set()->available(); 51 52 size_t threshold_bytes_allocated = capacity / 100 * ShenandoahAllocationThreshold; 53 size_t min_threshold = capacity / 100 * ShenandoahMinFreeThreshold; 54 55 if (available < min_threshold) { 56 log_info(gc)("Trigger: Free (" SIZE_FORMAT "%s) is below minimum threshold (" SIZE_FORMAT "%s)", 57 byte_size_in_proper_unit(available), proper_unit_for_byte_size(available), 58 byte_size_in_proper_unit(min_threshold), proper_unit_for_byte_size(min_threshold)); 59 return true; 60 } 61 62 size_t bytes_allocated = heap->bytes_allocated_since_gc_start(); 63 if (bytes_allocated > threshold_bytes_allocated) { 64 log_info(gc)("Trigger: Allocated since last cycle (" SIZE_FORMAT "%s) is larger than allocation threshold (" SIZE_FORMAT "%s)", 65 byte_size_in_proper_unit(bytes_allocated), proper_unit_for_byte_size(bytes_allocated), 66 byte_size_in_proper_unit(threshold_bytes_allocated), proper_unit_for_byte_size(threshold_bytes_allocated)); 67 return true; 68 } 69 70 return ShenandoahHeuristics::should_start_gc(); 71 } 72 73 void ShenandoahCompactHeuristics::choose_collection_set_from_regiondata(ShenandoahCollectionSet* cset, 74 RegionData* data, size_t size, 75 size_t actual_free) { 76 // Do not select too large CSet that would overflow the available free space 77 size_t max_cset = actual_free * 3 / 4; 78 79 log_info(gc, ergo)("CSet Selection. Actual Free: " SIZE_FORMAT "%s, Max CSet: " SIZE_FORMAT "%s", 80 byte_size_in_proper_unit(actual_free), proper_unit_for_byte_size(actual_free), 81 byte_size_in_proper_unit(max_cset), proper_unit_for_byte_size(max_cset)); 82 83 size_t threshold = ShenandoahHeapRegion::region_size_bytes() * ShenandoahGarbageThreshold / 100; 84 85 size_t live_cset = 0; 86 for (size_t idx = 0; idx < size; idx++) { 87 ShenandoahHeapRegion* r = data[idx]._region; 88 size_t new_cset = live_cset + r->get_live_data_bytes(); 89 if (new_cset < max_cset && r->garbage() > threshold) { 90 live_cset = new_cset; 91 cset->add_region(r); 92 } 93 } 94 } 95 96 const char* ShenandoahCompactHeuristics::name() { 97 return "compact"; 98 } 99 100 bool ShenandoahCompactHeuristics::is_diagnostic() { 101 return false; 102 } 103 104 bool ShenandoahCompactHeuristics::is_experimental() { 105 return false; 106 }