1 /* 2 * Copyright (c) 2001, 2013, Oracle and/or its affiliates. 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_VM_MEMORY_COLLECTORPOLICY_HPP 26 #define SHARE_VM_MEMORY_COLLECTORPOLICY_HPP 27 28 #include "memory/allocation.hpp" 29 #include "memory/barrierSet.hpp" 30 #include "memory/generationSpec.hpp" 31 #include "memory/genRemSet.hpp" 32 #include "utilities/macros.hpp" 33 34 // This class (or more correctly, subtypes of this class) 35 // are used to define global garbage collector attributes. 36 // This includes initialization of generations and any other 37 // shared resources they may need. 38 // 39 // In general, all flag adjustment and validation should be 40 // done in initialize_flags(), which is called prior to 41 // initialize_size_info(). 42 // 43 // This class is not fully developed yet. As more collector(s) 44 // are added, it is expected that we will come across further 45 // behavior that requires global attention. The correct place 46 // to deal with those issues is this class. 47 48 // Forward declarations. 49 class GenCollectorPolicy; 50 class AdaptiveSizePolicy; 51 #if INCLUDE_ALL_GCS 52 class ConcurrentMarkSweepPolicy; 53 class G1CollectorPolicy; 54 #endif // INCLUDE_ALL_GCS 55 56 class GCPolicyCounters; 57 class MarkSweepPolicy; 58 59 class CollectorPolicy : public CHeapObj<mtGC> { 60 protected: 61 GCPolicyCounters* _gc_policy_counters; 62 63 virtual void initialize_alignments() = 0; 64 virtual void initialize_flags(); 65 virtual void initialize_size_info(); 66 67 DEBUG_ONLY(virtual void assert_flags();) 68 DEBUG_ONLY(virtual void assert_size_info();) 69 70 size_t _initial_heap_byte_size; 71 size_t _max_heap_byte_size; 72 size_t _min_heap_byte_size; 73 74 size_t _space_alignment; 75 size_t _heap_alignment; 76 77 // Needed to keep information if MaxHeapSize was set on the command line 78 // when the flag value is aligned etc by ergonomics. 79 bool _max_heap_size_cmdline; 80 81 // The sizing of the heap is controlled by a sizing policy. 82 AdaptiveSizePolicy* _size_policy; 83 84 // Set to true when policy wants soft refs cleared. 85 // Reset to false by gc after it clears all soft refs. 86 bool _should_clear_all_soft_refs; 87 88 // Set to true by the GC if the just-completed gc cleared all 89 // softrefs. This is set to true whenever a gc clears all softrefs, and 90 // set to false each time gc returns to the mutator. For example, in the 91 // ParallelScavengeHeap case the latter would be done toward the end of 92 // mem_allocate() where it returns op.result() 93 bool _all_soft_refs_clear; 94 95 CollectorPolicy(); 96 97 public: 98 virtual void initialize_all() { 99 initialize_alignments(); 100 initialize_flags(); 101 initialize_size_info(); 102 } 103 104 // Return maximum heap alignment that may be imposed by the policy. 105 static size_t compute_heap_alignment(); 106 107 size_t space_alignment() { return _space_alignment; } 108 size_t heap_alignment() { return _heap_alignment; } 109 110 size_t initial_heap_byte_size() { return _initial_heap_byte_size; } 111 size_t max_heap_byte_size() { return _max_heap_byte_size; } 112 size_t min_heap_byte_size() { return _min_heap_byte_size; } 113 114 enum Name { 115 CollectorPolicyKind, 116 GenCollectorPolicyKind, 117 ConcurrentMarkSweepPolicyKind, 118 ASConcurrentMarkSweepPolicyKind, 119 G1CollectorPolicyKind 120 }; 121 122 AdaptiveSizePolicy* size_policy() { return _size_policy; } 123 bool should_clear_all_soft_refs() { return _should_clear_all_soft_refs; } 124 void set_should_clear_all_soft_refs(bool v) { _should_clear_all_soft_refs = v; } 125 // Returns the current value of _should_clear_all_soft_refs. 126 // _should_clear_all_soft_refs is set to false as a side effect. 127 bool use_should_clear_all_soft_refs(bool v); 128 bool all_soft_refs_clear() { return _all_soft_refs_clear; } 129 void set_all_soft_refs_clear(bool v) { _all_soft_refs_clear = v; } 130 131 // Called by the GC after Soft Refs have been cleared to indicate 132 // that the request in _should_clear_all_soft_refs has been fulfilled. 133 void cleared_all_soft_refs(); 134 135 // Identification methods. 136 virtual GenCollectorPolicy* as_generation_policy() { return NULL; } 137 virtual MarkSweepPolicy* as_mark_sweep_policy() { return NULL; } 138 #if INCLUDE_ALL_GCS 139 virtual ConcurrentMarkSweepPolicy* as_concurrent_mark_sweep_policy() { return NULL; } 140 virtual G1CollectorPolicy* as_g1_policy() { return NULL; } 141 #endif // INCLUDE_ALL_GCS 142 // Note that these are not virtual. 143 bool is_generation_policy() { return as_generation_policy() != NULL; } 144 bool is_mark_sweep_policy() { return as_mark_sweep_policy() != NULL; } 145 #if INCLUDE_ALL_GCS 146 bool is_concurrent_mark_sweep_policy() { return as_concurrent_mark_sweep_policy() != NULL; } 147 bool is_g1_policy() { return as_g1_policy() != NULL; } 148 #else // INCLUDE_ALL_GCS 149 bool is_concurrent_mark_sweep_policy() { return false; } 150 bool is_g1_policy() { return false; } 151 #endif // INCLUDE_ALL_GCS 152 153 154 virtual BarrierSet::Name barrier_set_name() = 0; 155 156 // Create the remembered set (to cover the given reserved region, 157 // allowing breaking up into at most "max_covered_regions"). 158 virtual GenRemSet* create_rem_set(MemRegion reserved, 159 int max_covered_regions); 160 161 // This method controls how a collector satisfies a request 162 // for a block of memory. "gc_time_limit_was_exceeded" will 163 // be set to true if the adaptive size policy determine that 164 // an excessive amount of time is being spent doing collections 165 // and caused a NULL to be returned. If a NULL is not returned, 166 // "gc_time_limit_was_exceeded" has an undefined meaning. 167 virtual HeapWord* mem_allocate_work(size_t size, 168 bool is_tlab, 169 bool* gc_overhead_limit_was_exceeded) = 0; 170 171 // This method controls how a collector handles one or more 172 // of its generations being fully allocated. 173 virtual HeapWord *satisfy_failed_allocation(size_t size, bool is_tlab) = 0; 174 // This method controls how a collector handles a metadata allocation 175 // failure. 176 virtual MetaWord* satisfy_failed_metadata_allocation(ClassLoaderData* loader_data, 177 size_t size, 178 Metaspace::MetadataType mdtype); 179 180 // Performance Counter support 181 GCPolicyCounters* counters() { return _gc_policy_counters; } 182 183 // Create the jstat counters for the GC policy. By default, policy's 184 // don't have associated counters, and we complain if this is invoked. 185 virtual void initialize_gc_policy_counters() { 186 ShouldNotReachHere(); 187 } 188 189 virtual CollectorPolicy::Name kind() { 190 return CollectorPolicy::CollectorPolicyKind; 191 } 192 193 // Returns true if a collector has eden space with soft end. 194 virtual bool has_soft_ended_eden() { 195 return false; 196 } 197 198 // Do any updates required to global flags that are due to heap initialization 199 // changes 200 virtual void post_heap_initialize() = 0; 201 }; 202 203 class ClearedAllSoftRefs : public StackObj { 204 bool _clear_all_soft_refs; 205 CollectorPolicy* _collector_policy; 206 public: 207 ClearedAllSoftRefs(bool clear_all_soft_refs, 208 CollectorPolicy* collector_policy) : 209 _clear_all_soft_refs(clear_all_soft_refs), 210 _collector_policy(collector_policy) {} 211 212 ~ClearedAllSoftRefs() { 213 if (_clear_all_soft_refs) { 214 _collector_policy->cleared_all_soft_refs(); 215 } 216 } 217 }; 218 219 class GenCollectorPolicy : public CollectorPolicy { 220 friend class TestGenCollectorPolicy; 221 protected: 222 size_t _min_gen0_size; 223 size_t _initial_gen0_size; 224 size_t _max_gen0_size; 225 size_t _min_gen1_size; 226 size_t _initial_gen1_size; 227 size_t _max_gen1_size; 228 229 // _gen_alignment and _space_alignment will have the same value most of the 230 // time. When using large pages they can differ. 231 size_t _gen_alignment; 232 233 GenerationSpec **_generations; 234 235 // Return true if an allocation should be attempted in the older generation 236 // if it fails in the younger generation. Return false, otherwise. 237 virtual bool should_try_older_generation_allocation(size_t word_size) const; 238 239 void initialize_flags(); 240 void initialize_size_info(); 241 242 DEBUG_ONLY(void assert_flags();) 243 DEBUG_ONLY(void assert_size_info();) 244 245 // Try to allocate space by expanding the heap. 246 virtual HeapWord* expand_heap_and_allocate(size_t size, bool is_tlab); 247 248 // Compute max heap alignment. 249 size_t compute_max_alignment(); 250 251 // Scale the base_size by NewRatio according to 252 // result = base_size / (NewRatio + 1) 253 // and align by min_alignment() 254 size_t scale_by_NewRatio_aligned(size_t base_size); 255 256 // Bound the value by the given maximum minus the min_alignment. 257 size_t bound_minus_alignment(size_t desired_size, size_t maximum_size); 258 259 public: 260 GenCollectorPolicy(); 261 262 // Accessors 263 size_t min_gen0_size() { return _min_gen0_size; } 264 size_t initial_gen0_size() { return _initial_gen0_size; } 265 size_t max_gen0_size() { return _max_gen0_size; } 266 size_t gen_alignment() { return _gen_alignment; } 267 size_t min_gen1_size() { return _min_gen1_size; } 268 size_t initial_gen1_size() { return _initial_gen1_size; } 269 size_t max_gen1_size() { return _max_gen1_size; } 270 271 int number_of_generations() { return 2; } 272 273 virtual GenerationSpec **generations() { 274 assert(_generations != NULL, "Sanity check"); 275 return _generations; 276 } 277 278 virtual GenCollectorPolicy* as_generation_policy() { return this; } 279 280 virtual void initialize_generations() { }; 281 282 virtual void initialize_all() { 283 CollectorPolicy::initialize_all(); 284 initialize_generations(); 285 } 286 287 size_t young_gen_size_lower_bound(); 288 289 HeapWord* mem_allocate_work(size_t size, 290 bool is_tlab, 291 bool* gc_overhead_limit_was_exceeded); 292 293 HeapWord *satisfy_failed_allocation(size_t size, bool is_tlab); 294 295 // Adaptive size policy 296 virtual void initialize_size_policy(size_t init_eden_size, 297 size_t init_promo_size, 298 size_t init_survivor_size); 299 300 virtual void post_heap_initialize() { 301 assert(_max_gen0_size == MaxNewSize, "Should be taken care of by initialize_size_info"); 302 } 303 304 BarrierSet::Name barrier_set_name() { return BarrierSet::CardTableModRef; } 305 306 virtual CollectorPolicy::Name kind() { 307 return CollectorPolicy::GenCollectorPolicyKind; 308 } 309 }; 310 311 class MarkSweepPolicy : public GenCollectorPolicy { 312 protected: 313 void initialize_alignments(); 314 void initialize_generations(); 315 316 public: 317 MarkSweepPolicy() {} 318 319 MarkSweepPolicy* as_mark_sweep_policy() { return this; } 320 321 void initialize_gc_policy_counters(); 322 }; 323 324 #endif // SHARE_VM_MEMORY_COLLECTORPOLICY_HPP