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
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:
145 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:
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:
187 bool is_empty_uncommitted() const { return _state == _empty_uncommitted; }
188 bool is_empty_committed() const { return _state == _empty_committed; }
189 bool is_regular() const { return _state == _regular; }
190 bool is_humongous_continuation() const { return _state == _humongous_cont; }
191
192 // Participation in logical groups:
193 bool is_empty() const { return is_empty_committed() || is_empty_uncommitted(); }
194 bool is_active() const { return !is_empty() && !is_trash(); }
195 bool is_trash() const { return _state == _trash; }
196 bool is_humongous_start() const { return _state == _humongous_start || _state == _pinned_humongous_start; }
197 bool is_humongous() const { return is_humongous_start() || is_humongous_continuation(); }
198 bool is_committed() const { return !is_empty_uncommitted(); }
199 bool is_cset() const { return _state == _cset || _state == _pinned_cset; }
200 bool is_pinned() const { return _state == _pinned || _state == _pinned_cset || _state == _pinned_humongous_start; }
201
202 // Macro-properties:
203 bool is_alloc_allowed() const { return is_empty() || is_regular() || _state == _pinned; }
204 bool is_stw_move_allowed() const { return is_regular() || _state == _cset || (ShenandoahHumongousMoves && _state == _humongous_start); }
205
206 RegionState state() const { return _state; }
207 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
257 double empty_time() {
258 return _empty_time;
259 }
260
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
265 inline static size_t region_count() {
266 return ShenandoahHeapRegion::RegionCount;
267 }
268
269 inline static size_t region_size_bytes() {
270 return ShenandoahHeapRegion::RegionSizeBytes;
271 }
272
273 inline static size_t region_size_words() {
274 return ShenandoahHeapRegion::RegionSizeWords;
275 }
276
277 inline static size_t region_size_bytes_shift() {
278 return ShenandoahHeapRegion::RegionSizeBytesShift;
279 }
280
281 inline static size_t region_size_words_shift() {
282 return ShenandoahHeapRegion::RegionSizeWordsShift;
283 }
284
285 inline static size_t region_size_bytes_mask() {
286 return ShenandoahHeapRegion::RegionSizeBytesMask;
287 }
288
289 inline static size_t region_size_words_mask() {
290 return ShenandoahHeapRegion::RegionSizeWordsMask;
291 }
292
293 // Convert to jint with sanity checking
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
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
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
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
317 inline static size_t humongous_threshold_bytes() {
318 return ShenandoahHeapRegion::HumongousThresholdBytes;
319 }
320
321 inline static size_t humongous_threshold_words() {
322 return ShenandoahHeapRegion::HumongousThresholdWords;
323 }
324
325 inline static size_t max_tlab_size_bytes() {
326 return ShenandoahHeapRegion::MaxTLABSizeBytes;
327 }
328
329 inline static size_t max_tlab_size_words() {
330 return ShenandoahHeapRegion::MaxTLABSizeWords;
331 }
332
333 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;
363 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
368 HeapWord* top() const { return _top; }
369 void set_top(HeapWord* v) { _top = v; }
370
371 HeapWord* new_top() const { return _new_top; }
372 void set_new_top(HeapWord* v) { _new_top = v; }
373
374 HeapWord* bottom() const { return _bottom; }
375 HeapWord* end() const { return _end; }
376
377 size_t capacity() const { return byte_size(bottom(), end()); }
378 size_t used() const { return byte_size(bottom(), top()); }
379 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