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 #ifndef SHARE_GC_SHENANDOAH_SHENANDOAHHEURISTICS_HPP 26 #define SHARE_GC_SHENANDOAH_SHENANDOAHHEURISTICS_HPP 27 28 #include "gc/shenandoah/shenandoahHeap.hpp" 29 #include "gc/shenandoah/shenandoahPhaseTimings.hpp" 30 #include "gc/shenandoah/shenandoahSharedVariables.hpp" 31 #include "memory/allocation.hpp" 32 #include "runtime/globals_extension.hpp" 33 34 #define SHENANDOAH_ERGO_DISABLE_FLAG(name) \ 35 do { \ 36 if (FLAG_IS_DEFAULT(name) && (name)) { \ 37 log_info(gc)("Heuristics ergonomically sets -XX:-" #name); \ 38 FLAG_SET_DEFAULT(name, false); \ 39 } \ 40 } while (0) 41 42 #define SHENANDOAH_ERGO_ENABLE_FLAG(name) \ 43 do { \ 44 if (FLAG_IS_DEFAULT(name) && !(name)) { \ 45 log_info(gc)("Heuristics ergonomically sets -XX:+" #name); \ 46 FLAG_SET_DEFAULT(name, true); \ 47 } \ 48 } while (0) 49 50 #define SHENANDOAH_ERGO_OVERRIDE_DEFAULT(name, value) \ 51 do { \ 52 if (FLAG_IS_DEFAULT(name)) { \ 53 log_info(gc)("Heuristics ergonomically sets -XX:" #name "=" #value); \ 54 FLAG_SET_DEFAULT(name, value); \ 55 } \ 56 } while (0) 57 58 #define SHENANDOAH_CHECK_FLAG_SET(name) \ 59 do { \ 60 if (!(name)) { \ 61 err_msg message("Heuristics needs -XX:+" #name " to work correctly"); \ 62 vm_exit_during_initialization("Error", message); \ 63 } \ 64 } while (0) 65 66 class ShenandoahCollectionSet; 67 class ShenandoahHeapRegion; 68 69 class ShenandoahHeuristics : public CHeapObj<mtGC> { 70 static const intx Concurrent_Adjust = -1; // recover from penalties 71 static const intx Degenerated_Penalty = 10; // how much to penalize average GC duration history on Degenerated GC 72 static const intx Full_Penalty = 20; // how much to penalize average GC duration history on Full GC 73 74 protected: 75 typedef struct { 76 ShenandoahHeapRegion* _region; 77 size_t _garbage; 78 uint64_t _seqnum_last_alloc; 79 } RegionData; 80 81 RegionData* _region_data; 82 size_t _region_data_size; 83 84 uint _degenerated_cycles_in_a_row; 85 uint _successful_cycles_in_a_row; 86 87 size_t _bytes_in_cset; 88 89 double _cycle_start; 90 double _last_cycle_end; 91 92 size_t _gc_times_learned; 93 intx _gc_time_penalties; 94 TruncatedSeq* _gc_time_history; 95 96 // There may be many threads that contend to set this flag 97 ShenandoahSharedFlag _metaspace_oom; 98 99 static int compare_by_garbage(RegionData a, RegionData b); 100 static int compare_by_garbage_then_alloc_seq_ascending(RegionData a, RegionData b); 101 static int compare_by_alloc_seq_ascending(RegionData a, RegionData b); 102 static int compare_by_alloc_seq_descending(RegionData a, RegionData b); 103 104 RegionData* get_region_data_cache(size_t num); 105 106 virtual void choose_collection_set_from_regiondata(ShenandoahCollectionSet* set, 107 RegionData* data, size_t data_size, 108 size_t free) = 0; 109 110 void adjust_penalty(intx step); 111 112 public: 113 ShenandoahHeuristics(); 114 virtual ~ShenandoahHeuristics(); 115 116 void record_gc_start(); 117 118 void record_gc_end(); 119 120 void record_metaspace_oom() { _metaspace_oom.set(); } 121 void clear_metaspace_oom() { _metaspace_oom.unset(); } 122 bool has_metaspace_oom() const { return _metaspace_oom.is_set(); } 123 124 virtual void record_cycle_start(); 125 126 virtual void record_cycle_end(); 127 128 virtual bool should_start_gc() const; 129 130 virtual bool should_degenerate_cycle(); 131 132 virtual void record_success_concurrent(); 133 134 virtual void record_success_degenerated(); 135 136 virtual void record_success_full(); 137 138 virtual void record_allocation_failure_gc(); 139 140 virtual void record_requested_gc(); 141 142 virtual void choose_collection_set(ShenandoahCollectionSet* collection_set); 143 144 virtual bool can_process_references(); 145 virtual bool should_process_references(); 146 147 virtual bool can_unload_classes(); 148 virtual bool can_unload_classes_normal(); 149 virtual bool should_unload_classes(); 150 151 virtual const char* name() = 0; 152 virtual bool is_diagnostic() = 0; 153 virtual bool is_experimental() = 0; 154 virtual void initialize(); 155 156 double time_since_last_gc() const; 157 }; 158 159 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHHEURISTICS_HPP