1 /* 2 * Copyright (c) 2013, 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_SHENANDOAHHEAPREGION_HPP 26 #define SHARE_GC_SHENANDOAH_SHENANDOAHHEAPREGION_HPP 27 28 #include "gc/shared/gc_globals.hpp" 29 #include "gc/shared/spaceDecorator.hpp" 30 #include "gc/shenandoah/shenandoahAllocRequest.hpp" 31 #include "gc/shenandoah/shenandoahAsserts.hpp" 32 #include "gc/shenandoah/shenandoahHeap.hpp" 33 #include "gc/shenandoah/shenandoahPacer.hpp" 34 #include "gc/shenandoah/shenandoahPadding.hpp" 35 #include "utilities/sizes.hpp" 36 37 class VMStructs; 38 class ShenandoahHeapRegionStateConstant; 39 40 class ShenandoahHeapRegion { 41 friend class VMStructs; 42 friend class ShenandoahHeapRegionStateConstant; 43 private: 44 /* 45 Region state is described by a state machine. Transitions are guarded by 46 heap lock, which allows changing the state of several regions atomically. 47 Region states can be logically aggregated in groups. 48 49 "Empty": 50 ................................................................. 51 . . 52 . . 53 . Uncommitted <------- Committed <------------------------\ 54 . | | . | 55 . \---------v-----------/ . | 56 . | . | 57 .........................|....................................... | 58 | | 59 "Active": | | 60 .........................|....................................... | 61 . | . | 62 . /-----------------^-------------------\ . | 63 . | | . | 64 . v v "Humongous": . | 65 . Regular ---\-----\ ..................O................ . | 66 . | ^ | | . | . . | 67 . | | | | . *---------\ . . | 68 . v | | | . v v . . | 69 . Pinned Cset | . HStart <--> H/Start H/Cont . . | 70 . ^ / | | . Pinned v | . . | 71 . | / | | . *<--------/ . . | 72 . | v | | . | . . | 73 . CsetPinned | | ..................O................ . | 74 . | | | . | 75 . \-----\---v-------------------/ . | 76 . | . | 77 .........................|....................................... | 78 | | 79 "Trash": | | 80 .........................|....................................... | 81 . | . | 82 . v . | 83 . Trash ---------------------------------------/ 84 . . 85 . . 86 ................................................................. 87 88 Transition from "Empty" to "Active" is first allocation. It can go from {Uncommitted, Committed} 89 to {Regular, "Humongous"}. The allocation may happen in Regular regions too, but not in Humongous. 90 91 Transition from "Active" to "Trash" is reclamation. It can go from CSet during the normal cycle, 92 and from {Regular, "Humongous"} for immediate reclamation. The existence of Trash state allows 93 quick reclamation without actual cleaning up. 94 95 Transition from "Trash" to "Empty" is recycling. It cleans up the regions and corresponding metadata. 96 Can be done asynchronously and in bulk. 97 98 Note how internal transitions disallow logic bugs: 99 a) No region can go Empty, unless properly reclaimed/recycled; 100 b) No region can go Uncommitted, unless reclaimed/recycled first; 101 c) Only Regular regions can go to CSet; 102 d) Pinned cannot go Trash, thus it could never be reclaimed until unpinned; 103 e) Pinned cannot go CSet, thus it never moves; 104 f) Humongous cannot be used for regular allocations; 105 g) Humongous cannot go CSet, thus it never moves; 106 h) Humongous start can go pinned, and thus can be protected from moves (humongous continuations should 107 follow associated humongous starts, not pinnable/movable by themselves); 108 i) Empty cannot go Trash, avoiding useless work; 109 j) ... 110 */ 111 112 enum RegionState { 113 _empty_uncommitted, // region is empty and has memory uncommitted 114 _empty_committed, // region is empty and has memory committed 115 _regular, // region is for regular allocations 116 _humongous_start, // region is the humongous start 117 _humongous_cont, // region is the humongous continuation 118 _pinned_humongous_start, // region is both humongous start and pinned 119 _cset, // region is in collection set 120 _pinned, // region is pinned 121 _pinned_cset, // region is pinned and in cset (evac failure path) 122 _trash, // region contains only trash 123 _REGION_STATES_NUM // last 124 }; 125 region_state_to_string(RegionState s)126 static const char* region_state_to_string(RegionState s) { 127 switch (s) { 128 case _empty_uncommitted: return "Empty Uncommitted"; 129 case _empty_committed: return "Empty Committed"; 130 case _regular: return "Regular"; 131 case _humongous_start: return "Humongous Start"; 132 case _humongous_cont: return "Humongous Continuation"; 133 case _pinned_humongous_start: return "Humongous Start, Pinned"; 134 case _cset: return "Collection Set"; 135 case _pinned: return "Pinned"; 136 case _pinned_cset: return "Collection Set, Pinned"; 137 case _trash: return "Trash"; 138 default: 139 ShouldNotReachHere(); 140 return ""; 141 } 142 } 143 144 // This method protects from accidental changes in enum order: region_state_to_ordinal(RegionState s) const145 int region_state_to_ordinal(RegionState s) const { 146 switch (s) { 147 case _empty_uncommitted: return 0; 148 case _empty_committed: return 1; 149 case _regular: return 2; 150 case _humongous_start: return 3; 151 case _humongous_cont: return 4; 152 case _cset: return 5; 153 case _pinned: return 6; 154 case _trash: return 7; 155 case _pinned_cset: return 8; 156 case _pinned_humongous_start: return 9; 157 default: 158 ShouldNotReachHere(); 159 return -1; 160 } 161 } 162 163 void report_illegal_transition(const char* method); 164 165 public: region_states_num()166 static const int region_states_num() { 167 return _REGION_STATES_NUM; 168 } 169 170 // Allowed transitions from the outside code: 171 void make_regular_allocation(); 172 void make_regular_bypass(); 173 void make_humongous_start(); 174 void make_humongous_cont(); 175 void make_humongous_start_bypass(); 176 void make_humongous_cont_bypass(); 177 void make_pinned(); 178 void make_unpinned(); 179 void make_cset(); 180 void make_trash(); 181 void make_trash_immediate(); 182 void make_empty(); 183 void make_uncommitted(); 184 void make_committed_bypass(); 185 186 // Individual states: is_empty_uncommitted() const187 bool is_empty_uncommitted() const { return _state == _empty_uncommitted; } is_empty_committed() const188 bool is_empty_committed() const { return _state == _empty_committed; } is_regular() const189 bool is_regular() const { return _state == _regular; } is_humongous_continuation() const190 bool is_humongous_continuation() const { return _state == _humongous_cont; } 191 192 // Participation in logical groups: is_empty() const193 bool is_empty() const { return is_empty_committed() || is_empty_uncommitted(); } is_active() const194 bool is_active() const { return !is_empty() && !is_trash(); } is_trash() const195 bool is_trash() const { return _state == _trash; } is_humongous_start() const196 bool is_humongous_start() const { return _state == _humongous_start || _state == _pinned_humongous_start; } is_humongous() const197 bool is_humongous() const { return is_humongous_start() || is_humongous_continuation(); } is_committed() const198 bool is_committed() const { return !is_empty_uncommitted(); } is_cset() const199 bool is_cset() const { return _state == _cset || _state == _pinned_cset; } is_pinned() const200 bool is_pinned() const { return _state == _pinned || _state == _pinned_cset || _state == _pinned_humongous_start; } 201 202 // Macro-properties: is_alloc_allowed() const203 bool is_alloc_allowed() const { return is_empty() || is_regular() || _state == _pinned; } is_stw_move_allowed() const204 bool is_stw_move_allowed() const { return is_regular() || _state == _cset || (ShenandoahHumongousMoves && _state == _humongous_start); } 205 state() const206 RegionState state() const { return _state; } state_ordinal() const207 int state_ordinal() const { return region_state_to_ordinal(_state); } 208 209 void record_pin(); 210 void record_unpin(); 211 size_t pin_count() const; 212 213 private: 214 static size_t RegionCount; 215 static size_t RegionSizeBytes; 216 static size_t RegionSizeWords; 217 static size_t RegionSizeBytesShift; 218 static size_t RegionSizeWordsShift; 219 static size_t RegionSizeBytesMask; 220 static size_t RegionSizeWordsMask; 221 static size_t HumongousThresholdBytes; 222 static size_t HumongousThresholdWords; 223 static size_t MaxTLABSizeBytes; 224 static size_t MaxTLABSizeWords; 225 226 // Never updated fields 227 size_t const _index; 228 HeapWord* const _bottom; 229 HeapWord* const _end; 230 231 // Rarely updated fields 232 HeapWord* _new_top; 233 double _empty_time; 234 235 // Seldom updated fields 236 RegionState _state; 237 238 // Frequently updated fields 239 HeapWord* _top; 240 241 size_t _tlab_allocs; 242 size_t _gclab_allocs; 243 244 volatile size_t _live_data; 245 volatile size_t _critical_pins; 246 247 HeapWord* volatile _update_watermark; 248 249 public: 250 ShenandoahHeapRegion(HeapWord* start, size_t index, bool committed); 251 252 static const size_t MIN_NUM_REGIONS = 10; 253 254 // Return adjusted max heap size 255 static size_t setup_sizes(size_t max_heap_size); 256 empty_time()257 double empty_time() { 258 return _empty_time; 259 } 260 required_regions(size_t bytes)261 inline static size_t required_regions(size_t bytes) { 262 return (bytes + ShenandoahHeapRegion::region_size_bytes() - 1) >> ShenandoahHeapRegion::region_size_bytes_shift(); 263 } 264 region_count()265 inline static size_t region_count() { 266 return ShenandoahHeapRegion::RegionCount; 267 } 268 region_size_bytes()269 inline static size_t region_size_bytes() { 270 return ShenandoahHeapRegion::RegionSizeBytes; 271 } 272 region_size_words()273 inline static size_t region_size_words() { 274 return ShenandoahHeapRegion::RegionSizeWords; 275 } 276 region_size_bytes_shift()277 inline static size_t region_size_bytes_shift() { 278 return ShenandoahHeapRegion::RegionSizeBytesShift; 279 } 280 region_size_words_shift()281 inline static size_t region_size_words_shift() { 282 return ShenandoahHeapRegion::RegionSizeWordsShift; 283 } 284 region_size_bytes_mask()285 inline static size_t region_size_bytes_mask() { 286 return ShenandoahHeapRegion::RegionSizeBytesMask; 287 } 288 region_size_words_mask()289 inline static size_t region_size_words_mask() { 290 return ShenandoahHeapRegion::RegionSizeWordsMask; 291 } 292 293 // Convert to jint with sanity checking region_size_bytes_jint()294 inline static jint region_size_bytes_jint() { 295 assert (ShenandoahHeapRegion::RegionSizeBytes <= (size_t)max_jint, "sanity"); 296 return (jint)ShenandoahHeapRegion::RegionSizeBytes; 297 } 298 299 // Convert to jint with sanity checking region_size_words_jint()300 inline static jint region_size_words_jint() { 301 assert (ShenandoahHeapRegion::RegionSizeWords <= (size_t)max_jint, "sanity"); 302 return (jint)ShenandoahHeapRegion::RegionSizeWords; 303 } 304 305 // Convert to jint with sanity checking region_size_bytes_shift_jint()306 inline static jint region_size_bytes_shift_jint() { 307 assert (ShenandoahHeapRegion::RegionSizeBytesShift <= (size_t)max_jint, "sanity"); 308 return (jint)ShenandoahHeapRegion::RegionSizeBytesShift; 309 } 310 311 // Convert to jint with sanity checking region_size_words_shift_jint()312 inline static jint region_size_words_shift_jint() { 313 assert (ShenandoahHeapRegion::RegionSizeWordsShift <= (size_t)max_jint, "sanity"); 314 return (jint)ShenandoahHeapRegion::RegionSizeWordsShift; 315 } 316 humongous_threshold_bytes()317 inline static size_t humongous_threshold_bytes() { 318 return ShenandoahHeapRegion::HumongousThresholdBytes; 319 } 320 humongous_threshold_words()321 inline static size_t humongous_threshold_words() { 322 return ShenandoahHeapRegion::HumongousThresholdWords; 323 } 324 max_tlab_size_bytes()325 inline static size_t max_tlab_size_bytes() { 326 return ShenandoahHeapRegion::MaxTLABSizeBytes; 327 } 328 max_tlab_size_words()329 inline static size_t max_tlab_size_words() { 330 return ShenandoahHeapRegion::MaxTLABSizeWords; 331 } 332 index() const333 inline size_t index() const { 334 return _index; 335 } 336 337 // Allocation (return NULL if full) 338 inline HeapWord* allocate(size_t word_size, ShenandoahAllocRequest::Type type); 339 340 inline void clear_live_data(); 341 void set_live_data(size_t s); 342 343 // Increase live data for newly allocated region 344 inline void increase_live_data_alloc_words(size_t s); 345 346 // Increase live data for region scanned with GC 347 inline void increase_live_data_gc_words(size_t s); 348 349 inline bool has_live() const; 350 inline size_t get_live_data_bytes() const; 351 inline size_t get_live_data_words() const; 352 353 inline size_t garbage() const; 354 355 void print_on(outputStream* st) const; 356 357 void recycle(); 358 359 void oop_iterate(OopIterateClosure* cl); 360 361 HeapWord* block_start(const void* p) const; 362 size_t block_size(const HeapWord* p) const; block_is_obj(const HeapWord * p) const363 bool block_is_obj(const HeapWord* p) const { return p < top(); } 364 365 // Find humongous start region that this region belongs to 366 ShenandoahHeapRegion* humongous_start_region() const; 367 top() const368 HeapWord* top() const { return _top; } set_top(HeapWord * v)369 void set_top(HeapWord* v) { _top = v; } 370 new_top() const371 HeapWord* new_top() const { return _new_top; } set_new_top(HeapWord * v)372 void set_new_top(HeapWord* v) { _new_top = v; } 373 bottom() const374 HeapWord* bottom() const { return _bottom; } end() const375 HeapWord* end() const { return _end; } 376 capacity() const377 size_t capacity() const { return byte_size(bottom(), end()); } used() const378 size_t used() const { return byte_size(bottom(), top()); } free() const379 size_t free() const { return byte_size(top(), end()); } 380 381 inline void adjust_alloc_metadata(ShenandoahAllocRequest::Type type, size_t); 382 void reset_alloc_metadata(); 383 size_t get_shared_allocs() const; 384 size_t get_tlab_allocs() const; 385 size_t get_gclab_allocs() const; 386 387 inline HeapWord* get_update_watermark() const; 388 inline void set_update_watermark(HeapWord* w); 389 inline void set_update_watermark_at_safepoint(HeapWord* w); 390 391 private: 392 void do_commit(); 393 void do_uncommit(); 394 395 void oop_iterate_objects(OopIterateClosure* cl); 396 void oop_iterate_humongous(OopIterateClosure* cl); 397 398 inline void internal_increase_live_data(size_t s); 399 400 void set_state(RegionState to); 401 }; 402 403 #endif // SHARE_GC_SHENANDOAH_SHENANDOAHHEAPREGION_HPP 404