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 #ifndef SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEURISTICS_HPP 25 #define SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEURISTICS_HPP 26 27 #include "gc/shenandoah/shenandoahHeap.hpp" 28 #include "gc/shenandoah/shenandoahPhaseTimings.hpp" 29 #include "gc/shenandoah/shenandoahSharedVariables.hpp" 30 #include "memory/allocation.hpp" 31 #include "runtime/globals_extension.hpp" 32 33 #define SHENANDOAH_ERGO_DISABLE_FLAG(name) \ 34 do { \ 35 if (FLAG_IS_DEFAULT(name) && (name)) { \ 36 log_info(gc)("Heuristics ergonomically sets -XX:-" #name); \ 37 FLAG_SET_DEFAULT(name, false); \ 38 } \ 39 } while (0) 40 41 #define SHENANDOAH_ERGO_ENABLE_FLAG(name) \ 42 do { \ 43 if (FLAG_IS_DEFAULT(name) && !(name)) { \ 44 log_info(gc)("Heuristics ergonomically sets -XX:+" #name); \ 45 FLAG_SET_DEFAULT(name, true); \ 46 } \ 47 } while (0) 48 49 #define SHENANDOAH_ERGO_OVERRIDE_DEFAULT(name, value) \ 50 do { \ 51 if (FLAG_IS_DEFAULT(name)) { \ 52 log_info(gc)("Heuristics ergonomically sets -XX:" #name "=" #value); \ 53 FLAG_SET_DEFAULT(name, value); \ 54 } \ 55 } while (0) 56 57 #define SHENANDOAH_CHECK_FLAG_SET(name) \ 58 do { \ 59 if (!name) { \ 60 err_msg message("Heuristics needs -XX:+" #name " to work correctly"); \ 61 vm_exit_during_initialization("Error", message); \ 62 } \ 63 } while (0) 64 65 class ShenandoahCollectionSet; 66 class ShenandoahHeapRegion; 67 68 class ShenandoahHeuristics : public CHeapObj<mtGC> { 69 static const intx Concurrent_Adjust = 1; // recover from penalties 70 static const intx Degenerated_Penalty = 10; // how much to penalize average GC duration history on Degenerated GC 71 static const intx Full_Penalty = 20; // how much to penalize average GC duration history on Full GC 72 73 protected: 74 typedef struct { 75 ShenandoahHeapRegion* _region; 76 size_t _garbage; 77 uint64_t _seqnum_last_alloc; 78 } RegionData; 79 80 bool _update_refs_early; 81 bool _update_refs_adaptive; 82 83 RegionData* _region_data; 84 size_t _region_data_size; 85 86 uint _degenerated_cycles_in_a_row; 87 uint _successful_cycles_in_a_row; 88 89 size_t _bytes_in_cset; 90 91 double _cycle_start; 92 double _last_cycle_end; 93 94 size_t _gc_times_learned; 95 size_t _gc_time_penalties; 96 TruncatedSeq* _gc_time_history; 97 98 // There may be many threads that contend to set this flag 99 ShenandoahSharedFlag _metaspace_oom; 100 101 static int compare_by_garbage(RegionData a, RegionData b); 102 static int compare_by_garbage_then_alloc_seq_ascending(RegionData a, RegionData b); 103 static int compare_by_alloc_seq_ascending(RegionData a, RegionData b); 104 static int compare_by_alloc_seq_descending(RegionData a, RegionData b); 105 106 RegionData* get_region_data_cache(size_t num); 107 108 virtual void choose_collection_set_from_regiondata(ShenandoahCollectionSet* set, 109 RegionData* data, size_t data_size, 110 size_t free) = 0; 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 void record_phase_time(ShenandoahPhaseTimings::Phase phase, double secs); 129 130 virtual bool should_start_normal_gc() const; 131 132 virtual bool should_start_update_refs(); 133 134 virtual bool should_start_traversal_gc(); 135 136 virtual bool can_do_traversal_gc(); 137 138 virtual bool should_degenerate_cycle(); 139 140 virtual void record_success_concurrent(); 141 142 virtual void record_success_degenerated(); 143 144 virtual void record_success_full(); 145 146 virtual void record_allocation_failure_gc(); 147 148 virtual void record_requested_gc(); 149 150 virtual void choose_collection_set(ShenandoahCollectionSet* collection_set); 151 152 virtual bool can_process_references(); 153 virtual bool should_process_references(); 154 155 virtual bool can_unload_classes(); 156 virtual bool can_unload_classes_normal(); 157 virtual bool should_unload_classes(); 158 159 virtual const char* name() = 0; 160 virtual bool is_diagnostic() = 0; 161 virtual bool is_experimental() = 0; 162 virtual void initialize(); 163 164 double time_since_last_gc() const; 165 }; 166 167 #endif // SHARE_VM_GC_SHENANDOAH_SHENANDOAHHEURISTICS_HPP