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