Tue, 25 Sep 2012 07:05:55 -0700
7200615: NPG: optimized VM build is broken
Reviewed-by: kvn
1 /*
2 * Copyright (c) 2001, 2012, 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
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23 */
25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP
28 #include "gc_implementation/g1/sparsePRT.hpp"
30 // Remembered set for a heap region. Represent a set of "cards" that
31 // contain pointers into the owner heap region. Cards are defined somewhat
32 // abstractly, in terms of what the "BlockOffsetTable" in use can parse.
34 class G1CollectedHeap;
35 class G1BlockOffsetSharedArray;
36 class HeapRegion;
37 class HeapRegionRemSetIterator;
38 class PerRegionTable;
39 class SparsePRT;
41 // Essentially a wrapper around SparsePRTCleanupTask. See
42 // sparsePRT.hpp for more details.
43 class HRRSCleanupTask : public SparsePRTCleanupTask {
44 };
46 // The "_coarse_map" is a bitmap with one bit for each region, where set
47 // bits indicate that the corresponding region may contain some pointer
48 // into the owning region.
50 // The "_fine_grain_entries" array is an open hash table of PerRegionTables
51 // (PRTs), indicating regions for which we're keeping the RS as a set of
52 // cards. The strategy is to cap the size of the fine-grain table,
53 // deleting an entry and setting the corresponding coarse-grained bit when
54 // we would overflow this cap.
56 // We use a mixture of locking and lock-free techniques here. We allow
57 // threads to locate PRTs without locking, but threads attempting to alter
58 // a bucket list obtain a lock. This means that any failing attempt to
59 // find a PRT must be retried with the lock. It might seem dangerous that
60 // a read can find a PRT that is concurrently deleted. This is all right,
61 // because:
62 //
63 // 1) We only actually free PRT's at safe points (though we reuse them at
64 // other times).
65 // 2) We find PRT's in an attempt to add entries. If a PRT is deleted,
66 // it's _coarse_map bit is set, so the that we were attempting to add
67 // is represented. If a deleted PRT is re-used, a thread adding a bit,
68 // thinking the PRT is for a different region, does no harm.
70 class OtherRegionsTable VALUE_OBJ_CLASS_SPEC {
71 friend class HeapRegionRemSetIterator;
73 G1CollectedHeap* _g1h;
74 Mutex _m;
75 HeapRegion* _hr;
77 // These are protected by "_m".
78 BitMap _coarse_map;
79 size_t _n_coarse_entries;
80 static jint _n_coarsenings;
82 PerRegionTable** _fine_grain_regions;
83 size_t _n_fine_entries;
85 // The fine grain remembered sets are doubly linked together using
86 // their 'next' and 'prev' fields.
87 // This allows fast bulk freeing of all the fine grain remembered
88 // set entries, and fast finding of all of them without iterating
89 // over the _fine_grain_regions table.
90 PerRegionTable * _first_all_fine_prts;
91 PerRegionTable * _last_all_fine_prts;
93 // Used to sample a subset of the fine grain PRTs to determine which
94 // PRT to evict and coarsen.
95 size_t _fine_eviction_start;
96 static size_t _fine_eviction_stride;
97 static size_t _fine_eviction_sample_size;
99 SparsePRT _sparse_table;
101 // These are static after init.
102 static size_t _max_fine_entries;
103 static size_t _mod_max_fine_entries_mask;
105 // Requires "prt" to be the first element of the bucket list appropriate
106 // for "hr". If this list contains an entry for "hr", return it,
107 // otherwise return "NULL".
108 PerRegionTable* find_region_table(size_t ind, HeapRegion* hr) const;
110 // Find, delete, and return a candidate PerRegionTable, if any exists,
111 // adding the deleted region to the coarse bitmap. Requires the caller
112 // to hold _m, and the fine-grain table to be full.
113 PerRegionTable* delete_region_table();
115 // If a PRT for "hr" is in the bucket list indicated by "ind" (which must
116 // be the correct index for "hr"), delete it and return true; else return
117 // false.
118 bool del_single_region_table(size_t ind, HeapRegion* hr);
120 // Indexed by thread X heap region, to minimize thread contention.
121 static int** _from_card_cache;
122 static size_t _from_card_cache_max_regions;
123 static size_t _from_card_cache_mem_size;
125 // link/add the given fine grain remembered set into the "all" list
126 void link_to_all(PerRegionTable * prt);
127 // unlink/remove the given fine grain remembered set into the "all" list
128 void unlink_from_all(PerRegionTable * prt);
130 public:
131 OtherRegionsTable(HeapRegion* hr);
133 HeapRegion* hr() const { return _hr; }
135 // For now. Could "expand" some tables in the future, so that this made
136 // sense.
137 void add_reference(OopOrNarrowOopStar from, int tid);
139 // Removes any entries shown by the given bitmaps to contain only dead
140 // objects.
141 void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm);
143 // Not const because it takes a lock.
144 size_t occupied() const;
145 size_t occ_fine() const;
146 size_t occ_coarse() const;
147 size_t occ_sparse() const;
149 static jint n_coarsenings() { return _n_coarsenings; }
151 // Returns size in bytes.
152 // Not const because it takes a lock.
153 size_t mem_size() const;
154 static size_t static_mem_size();
155 static size_t fl_mem_size();
157 bool contains_reference(OopOrNarrowOopStar from) const;
158 bool contains_reference_locked(OopOrNarrowOopStar from) const;
160 void clear();
162 // Specifically clear the from_card_cache.
163 void clear_fcc();
165 // "from_hr" is being cleared; remove any entries from it.
166 void clear_incoming_entry(HeapRegion* from_hr);
168 void do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task);
170 // Declare the heap size (in # of regions) to the OtherRegionsTable.
171 // (Uses it to initialize from_card_cache).
172 static void init_from_card_cache(size_t max_regions);
174 // Declares that only regions i s.t. 0 <= i < new_n_regs are in use.
175 // Make sure any entries for higher regions are invalid.
176 static void shrink_from_card_cache(size_t new_n_regs);
178 static void print_from_card_cache();
179 };
181 class HeapRegionRemSet : public CHeapObj<mtGC> {
182 friend class VMStructs;
183 friend class HeapRegionRemSetIterator;
185 public:
186 enum Event {
187 Event_EvacStart, Event_EvacEnd, Event_RSUpdateEnd
188 };
190 private:
191 G1BlockOffsetSharedArray* _bosa;
192 G1BlockOffsetSharedArray* bosa() const { return _bosa; }
194 OtherRegionsTable _other_regions;
196 enum ParIterState { Unclaimed, Claimed, Complete };
197 volatile ParIterState _iter_state;
198 volatile jlong _iter_claimed;
200 // Unused unless G1RecordHRRSOops is true.
202 static const int MaxRecorded = 1000000;
203 static OopOrNarrowOopStar* _recorded_oops;
204 static HeapWord** _recorded_cards;
205 static HeapRegion** _recorded_regions;
206 static int _n_recorded;
208 static const int MaxRecordedEvents = 1000;
209 static Event* _recorded_events;
210 static int* _recorded_event_index;
211 static int _n_recorded_events;
213 static void print_event(outputStream* str, Event evnt);
215 public:
216 HeapRegionRemSet(G1BlockOffsetSharedArray* bosa,
217 HeapRegion* hr);
219 static int num_par_rem_sets();
220 static void setup_remset_size();
222 HeapRegion* hr() const {
223 return _other_regions.hr();
224 }
226 size_t occupied() const {
227 return _other_regions.occupied();
228 }
229 size_t occ_fine() const {
230 return _other_regions.occ_fine();
231 }
232 size_t occ_coarse() const {
233 return _other_regions.occ_coarse();
234 }
235 size_t occ_sparse() const {
236 return _other_regions.occ_sparse();
237 }
239 static jint n_coarsenings() { return OtherRegionsTable::n_coarsenings(); }
241 // Used in the sequential case.
242 void add_reference(OopOrNarrowOopStar from) {
243 _other_regions.add_reference(from, 0);
244 }
246 // Used in the parallel case.
247 void add_reference(OopOrNarrowOopStar from, int tid) {
248 _other_regions.add_reference(from, tid);
249 }
251 // Removes any entries shown by the given bitmaps to contain only dead
252 // objects.
253 void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm);
255 // The region is being reclaimed; clear its remset, and any mention of
256 // entries for this region in other remsets.
257 void clear();
259 // Attempt to claim the region. Returns true iff this call caused an
260 // atomic transition from Unclaimed to Claimed.
261 bool claim_iter();
262 // Sets the iteration state to "complete".
263 void set_iter_complete();
264 // Returns "true" iff the region's iteration is complete.
265 bool iter_is_complete();
267 // Support for claiming blocks of cards during iteration
268 size_t iter_claimed() const { return (size_t)_iter_claimed; }
269 // Claim the next block of cards
270 size_t iter_claimed_next(size_t step) {
271 size_t current, next;
272 do {
273 current = iter_claimed();
274 next = current + step;
275 } while (Atomic::cmpxchg((jlong)next, &_iter_claimed, (jlong)current) != (jlong)current);
276 return current;
277 }
278 void reset_for_par_iteration();
280 bool verify_ready_for_par_iteration() {
281 return (_iter_state == Unclaimed) && (_iter_claimed == 0);
282 }
284 // Initialize the given iterator to iterate over this rem set.
285 void init_iterator(HeapRegionRemSetIterator* iter) const;
287 // The actual # of bytes this hr_remset takes up.
288 size_t mem_size() {
289 return _other_regions.mem_size()
290 // This correction is necessary because the above includes the second
291 // part.
292 + sizeof(this) - sizeof(OtherRegionsTable);
293 }
295 // Returns the memory occupancy of all static data structures associated
296 // with remembered sets.
297 static size_t static_mem_size() {
298 return OtherRegionsTable::static_mem_size();
299 }
301 // Returns the memory occupancy of all free_list data structures associated
302 // with remembered sets.
303 static size_t fl_mem_size() {
304 return OtherRegionsTable::fl_mem_size();
305 }
307 bool contains_reference(OopOrNarrowOopStar from) const {
308 return _other_regions.contains_reference(from);
309 }
310 void print() const;
312 // Called during a stop-world phase to perform any deferred cleanups.
313 static void cleanup();
315 // Declare the heap size (in # of regions) to the HeapRegionRemSet(s).
316 // (Uses it to initialize from_card_cache).
317 static void init_heap(uint max_regions) {
318 OtherRegionsTable::init_from_card_cache((size_t) max_regions);
319 }
321 // Declares that only regions i s.t. 0 <= i < new_n_regs are in use.
322 static void shrink_heap(uint new_n_regs) {
323 OtherRegionsTable::shrink_from_card_cache((size_t) new_n_regs);
324 }
326 #ifndef PRODUCT
327 static void print_from_card_cache() {
328 OtherRegionsTable::print_from_card_cache();
329 }
330 #endif
332 static void record(HeapRegion* hr, OopOrNarrowOopStar f);
333 static void print_recorded();
334 static void record_event(Event evnt);
336 // These are wrappers for the similarly-named methods on
337 // SparsePRT. Look at sparsePRT.hpp for more details.
338 static void reset_for_cleanup_tasks();
339 void do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task);
340 static void finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task);
342 // Run unit tests.
343 #ifndef PRODUCT
344 static void test();
345 #endif
346 };
348 class HeapRegionRemSetIterator : public CHeapObj<mtGC> {
350 // The region over which we're iterating.
351 const HeapRegionRemSet* _hrrs;
353 // Local caching of HRRS fields.
354 const BitMap* _coarse_map;
355 PerRegionTable** _fine_grain_regions;
357 G1BlockOffsetSharedArray* _bosa;
358 G1CollectedHeap* _g1h;
360 // The number yielded since initialization.
361 size_t _n_yielded_fine;
362 size_t _n_yielded_coarse;
363 size_t _n_yielded_sparse;
365 // If true we're iterating over the coarse table; if false the fine
366 // table.
367 enum IterState {
368 Sparse,
369 Fine,
370 Coarse
371 };
372 IterState _is;
374 // In both kinds of iteration, heap offset of first card of current
375 // region.
376 size_t _cur_region_card_offset;
377 // Card offset within cur region.
378 size_t _cur_region_cur_card;
380 // Coarse table iteration fields:
382 // Current region index;
383 int _coarse_cur_region_index;
384 size_t _coarse_cur_region_cur_card;
386 bool coarse_has_next(size_t& card_index);
388 // Fine table iteration fields:
390 // Index of bucket-list we're working on.
391 int _fine_array_index;
393 // Per Region Table we're doing within current bucket list.
394 PerRegionTable* _fine_cur_prt;
396 /* SparsePRT::*/ SparsePRTIter _sparse_iter;
398 void fine_find_next_non_null_prt();
400 bool fine_has_next();
401 bool fine_has_next(size_t& card_index);
403 public:
404 // We require an iterator to be initialized before use, so the
405 // constructor does little.
406 HeapRegionRemSetIterator();
408 void initialize(const HeapRegionRemSet* hrrs);
410 // If there remains one or more cards to be yielded, returns true and
411 // sets "card_index" to one of those cards (which is then considered
412 // yielded.) Otherwise, returns false (and leaves "card_index"
413 // undefined.)
414 bool has_next(size_t& card_index);
416 size_t n_yielded_fine() { return _n_yielded_fine; }
417 size_t n_yielded_coarse() { return _n_yielded_coarse; }
418 size_t n_yielded_sparse() { return _n_yielded_sparse; }
419 size_t n_yielded() {
420 return n_yielded_fine() + n_yielded_coarse() + n_yielded_sparse();
421 }
422 };
424 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP