Tue, 19 May 2015 15:49:27 +0200
8061715: gc/g1/TestShrinkAuxiliaryData15.java fails with java.lang.RuntimeException: heap decommit failed - after > before
Summary: added WhiteBox methods to count regions and exact aux data sizes
Reviewed-by: jwilhelm, brutisso
1 /*
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3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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25 #ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP
26 #define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP
28 #include "gc_implementation/g1/g1CodeCacheRemSet.hpp"
29 #include "gc_implementation/g1/sparsePRT.hpp"
31 // Remembered set for a heap region. Represent a set of "cards" that
32 // contain pointers into the owner heap region. Cards are defined somewhat
33 // abstractly, in terms of what the "BlockOffsetTable" in use can parse.
35 class G1CollectedHeap;
36 class G1BlockOffsetSharedArray;
37 class HeapRegion;
38 class HeapRegionRemSetIterator;
39 class PerRegionTable;
40 class SparsePRT;
41 class nmethod;
43 // Essentially a wrapper around SparsePRTCleanupTask. See
44 // sparsePRT.hpp for more details.
45 class HRRSCleanupTask : public SparsePRTCleanupTask {
46 };
48 // The FromCardCache remembers the most recently processed card on the heap on
49 // a per-region and per-thread basis.
50 class FromCardCache : public AllStatic {
51 private:
52 // Array of card indices. Indexed by thread X and heap region to minimize
53 // thread contention.
54 static int** _cache;
55 static uint _max_regions;
56 static size_t _static_mem_size;
58 public:
59 enum {
60 InvalidCard = -1 // Card value of an invalid card, i.e. a card index not otherwise used.
61 };
63 static void clear(uint region_idx);
65 // Returns true if the given card is in the cache at the given location, or
66 // replaces the card at that location and returns false.
67 static bool contains_or_replace(uint worker_id, uint region_idx, int card) {
68 int card_in_cache = at(worker_id, region_idx);
69 if (card_in_cache == card) {
70 return true;
71 } else {
72 set(worker_id, region_idx, card);
73 return false;
74 }
75 }
77 static int at(uint worker_id, uint region_idx) {
78 return _cache[worker_id][region_idx];
79 }
81 static void set(uint worker_id, uint region_idx, int val) {
82 _cache[worker_id][region_idx] = val;
83 }
85 static void initialize(uint n_par_rs, uint max_num_regions);
87 static void invalidate(uint start_idx, size_t num_regions);
89 static void print(outputStream* out = gclog_or_tty) PRODUCT_RETURN;
91 static size_t static_mem_size() {
92 return _static_mem_size;
93 }
94 };
96 // The "_coarse_map" is a bitmap with one bit for each region, where set
97 // bits indicate that the corresponding region may contain some pointer
98 // into the owning region.
100 // The "_fine_grain_entries" array is an open hash table of PerRegionTables
101 // (PRTs), indicating regions for which we're keeping the RS as a set of
102 // cards. The strategy is to cap the size of the fine-grain table,
103 // deleting an entry and setting the corresponding coarse-grained bit when
104 // we would overflow this cap.
106 // We use a mixture of locking and lock-free techniques here. We allow
107 // threads to locate PRTs without locking, but threads attempting to alter
108 // a bucket list obtain a lock. This means that any failing attempt to
109 // find a PRT must be retried with the lock. It might seem dangerous that
110 // a read can find a PRT that is concurrently deleted. This is all right,
111 // because:
112 //
113 // 1) We only actually free PRT's at safe points (though we reuse them at
114 // other times).
115 // 2) We find PRT's in an attempt to add entries. If a PRT is deleted,
116 // it's _coarse_map bit is set, so the that we were attempting to add
117 // is represented. If a deleted PRT is re-used, a thread adding a bit,
118 // thinking the PRT is for a different region, does no harm.
120 class OtherRegionsTable VALUE_OBJ_CLASS_SPEC {
121 friend class HeapRegionRemSetIterator;
123 G1CollectedHeap* _g1h;
124 Mutex* _m;
125 HeapRegion* _hr;
127 // These are protected by "_m".
128 BitMap _coarse_map;
129 size_t _n_coarse_entries;
130 static jint _n_coarsenings;
132 PerRegionTable** _fine_grain_regions;
133 size_t _n_fine_entries;
135 // The fine grain remembered sets are doubly linked together using
136 // their 'next' and 'prev' fields.
137 // This allows fast bulk freeing of all the fine grain remembered
138 // set entries, and fast finding of all of them without iterating
139 // over the _fine_grain_regions table.
140 PerRegionTable * _first_all_fine_prts;
141 PerRegionTable * _last_all_fine_prts;
143 // Used to sample a subset of the fine grain PRTs to determine which
144 // PRT to evict and coarsen.
145 size_t _fine_eviction_start;
146 static size_t _fine_eviction_stride;
147 static size_t _fine_eviction_sample_size;
149 SparsePRT _sparse_table;
151 // These are static after init.
152 static size_t _max_fine_entries;
153 static size_t _mod_max_fine_entries_mask;
155 // Requires "prt" to be the first element of the bucket list appropriate
156 // for "hr". If this list contains an entry for "hr", return it,
157 // otherwise return "NULL".
158 PerRegionTable* find_region_table(size_t ind, HeapRegion* hr) const;
160 // Find, delete, and return a candidate PerRegionTable, if any exists,
161 // adding the deleted region to the coarse bitmap. Requires the caller
162 // to hold _m, and the fine-grain table to be full.
163 PerRegionTable* delete_region_table();
165 // If a PRT for "hr" is in the bucket list indicated by "ind" (which must
166 // be the correct index for "hr"), delete it and return true; else return
167 // false.
168 bool del_single_region_table(size_t ind, HeapRegion* hr);
170 // link/add the given fine grain remembered set into the "all" list
171 void link_to_all(PerRegionTable * prt);
172 // unlink/remove the given fine grain remembered set into the "all" list
173 void unlink_from_all(PerRegionTable * prt);
175 public:
176 OtherRegionsTable(HeapRegion* hr, Mutex* m);
178 HeapRegion* hr() const { return _hr; }
180 // For now. Could "expand" some tables in the future, so that this made
181 // sense.
182 void add_reference(OopOrNarrowOopStar from, int tid);
184 // Returns whether this remembered set (and all sub-sets) have an occupancy
185 // that is less or equal than the given occupancy.
186 bool occupancy_less_or_equal_than(size_t limit) const;
188 // Removes any entries shown by the given bitmaps to contain only dead
189 // objects.
190 void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm);
192 // Returns whether this remembered set (and all sub-sets) contain no entries.
193 bool is_empty() const;
195 size_t occupied() const;
196 size_t occ_fine() const;
197 size_t occ_coarse() const;
198 size_t occ_sparse() const;
200 static jint n_coarsenings() { return _n_coarsenings; }
202 // Returns size in bytes.
203 // Not const because it takes a lock.
204 size_t mem_size() const;
205 static size_t static_mem_size();
206 static size_t fl_mem_size();
208 bool contains_reference(OopOrNarrowOopStar from) const;
209 bool contains_reference_locked(OopOrNarrowOopStar from) const;
211 void clear();
213 // Specifically clear the from_card_cache.
214 void clear_fcc();
216 void do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task);
218 // Declare the heap size (in # of regions) to the OtherRegionsTable.
219 // (Uses it to initialize from_card_cache).
220 static void initialize(uint max_regions);
222 // Declares that regions between start_idx <= i < start_idx + num_regions are
223 // not in use. Make sure that any entries for these regions are invalid.
224 static void invalidate(uint start_idx, size_t num_regions);
226 static void print_from_card_cache();
227 };
229 class HeapRegionRemSet : public CHeapObj<mtGC> {
230 friend class VMStructs;
231 friend class HeapRegionRemSetIterator;
233 public:
234 enum Event {
235 Event_EvacStart, Event_EvacEnd, Event_RSUpdateEnd
236 };
238 private:
239 G1BlockOffsetSharedArray* _bosa;
240 G1BlockOffsetSharedArray* bosa() const { return _bosa; }
242 // A set of code blobs (nmethods) whose code contains pointers into
243 // the region that owns this RSet.
244 G1CodeRootSet _code_roots;
246 Mutex _m;
248 OtherRegionsTable _other_regions;
250 enum ParIterState { Unclaimed, Claimed, Complete };
251 volatile ParIterState _iter_state;
252 volatile jlong _iter_claimed;
254 // Unused unless G1RecordHRRSOops is true.
256 static const int MaxRecorded = 1000000;
257 static OopOrNarrowOopStar* _recorded_oops;
258 static HeapWord** _recorded_cards;
259 static HeapRegion** _recorded_regions;
260 static int _n_recorded;
262 static const int MaxRecordedEvents = 1000;
263 static Event* _recorded_events;
264 static int* _recorded_event_index;
265 static int _n_recorded_events;
267 static void print_event(outputStream* str, Event evnt);
269 public:
270 HeapRegionRemSet(G1BlockOffsetSharedArray* bosa, HeapRegion* hr);
272 static uint num_par_rem_sets();
273 static void setup_remset_size();
275 HeapRegion* hr() const {
276 return _other_regions.hr();
277 }
279 bool is_empty() const {
280 return (strong_code_roots_list_length() == 0) && _other_regions.is_empty();
281 }
283 bool occupancy_less_or_equal_than(size_t occ) const {
284 return (strong_code_roots_list_length() == 0) && _other_regions.occupancy_less_or_equal_than(occ);
285 }
287 size_t occupied() {
288 MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
289 return occupied_locked();
290 }
291 size_t occupied_locked() {
292 return _other_regions.occupied();
293 }
294 size_t occ_fine() const {
295 return _other_regions.occ_fine();
296 }
297 size_t occ_coarse() const {
298 return _other_regions.occ_coarse();
299 }
300 size_t occ_sparse() const {
301 return _other_regions.occ_sparse();
302 }
304 static jint n_coarsenings() { return OtherRegionsTable::n_coarsenings(); }
306 // Used in the sequential case.
307 void add_reference(OopOrNarrowOopStar from) {
308 _other_regions.add_reference(from, 0);
309 }
311 // Used in the parallel case.
312 void add_reference(OopOrNarrowOopStar from, int tid) {
313 _other_regions.add_reference(from, tid);
314 }
316 // Removes any entries shown by the given bitmaps to contain only dead
317 // objects.
318 void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm);
320 // The region is being reclaimed; clear its remset, and any mention of
321 // entries for this region in other remsets.
322 void clear();
323 void clear_locked();
325 // Attempt to claim the region. Returns true iff this call caused an
326 // atomic transition from Unclaimed to Claimed.
327 bool claim_iter();
328 // Sets the iteration state to "complete".
329 void set_iter_complete();
330 // Returns "true" iff the region's iteration is complete.
331 bool iter_is_complete();
333 // Support for claiming blocks of cards during iteration
334 size_t iter_claimed() const { return (size_t)_iter_claimed; }
335 // Claim the next block of cards
336 size_t iter_claimed_next(size_t step) {
337 size_t current, next;
338 do {
339 current = iter_claimed();
340 next = current + step;
341 } while (Atomic::cmpxchg((jlong)next, &_iter_claimed, (jlong)current) != (jlong)current);
342 return current;
343 }
344 void reset_for_par_iteration();
346 bool verify_ready_for_par_iteration() {
347 return (_iter_state == Unclaimed) && (_iter_claimed == 0);
348 }
350 // The actual # of bytes this hr_remset takes up.
351 // Note also includes the strong code root set.
352 size_t mem_size() {
353 MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
354 return _other_regions.mem_size()
355 // This correction is necessary because the above includes the second
356 // part.
357 + (sizeof(HeapRegionRemSet) - sizeof(OtherRegionsTable))
358 + strong_code_roots_mem_size();
359 }
361 // Returns the memory occupancy of all static data structures associated
362 // with remembered sets.
363 static size_t static_mem_size() {
364 return OtherRegionsTable::static_mem_size() + G1CodeRootSet::static_mem_size();
365 }
367 // Returns the memory occupancy of all free_list data structures associated
368 // with remembered sets.
369 static size_t fl_mem_size() {
370 return OtherRegionsTable::fl_mem_size();
371 }
373 bool contains_reference(OopOrNarrowOopStar from) const {
374 return _other_regions.contains_reference(from);
375 }
377 // Routines for managing the list of code roots that point into
378 // the heap region that owns this RSet.
379 void add_strong_code_root(nmethod* nm);
380 void add_strong_code_root_locked(nmethod* nm);
381 void remove_strong_code_root(nmethod* nm);
383 // Applies blk->do_code_blob() to each of the entries in
384 // the strong code roots list
385 void strong_code_roots_do(CodeBlobClosure* blk) const;
387 void clean_strong_code_roots(HeapRegion* hr);
389 // Returns the number of elements in the strong code roots list
390 size_t strong_code_roots_list_length() const {
391 return _code_roots.length();
392 }
394 // Returns true if the strong code roots contains the given
395 // nmethod.
396 bool strong_code_roots_list_contains(nmethod* nm) {
397 return _code_roots.contains(nm);
398 }
400 // Returns the amount of memory, in bytes, currently
401 // consumed by the strong code roots.
402 size_t strong_code_roots_mem_size();
404 void print() PRODUCT_RETURN;
406 // Called during a stop-world phase to perform any deferred cleanups.
407 static void cleanup();
409 // Declare the heap size (in # of regions) to the HeapRegionRemSet(s).
410 // (Uses it to initialize from_card_cache).
411 static void init_heap(uint max_regions) {
412 OtherRegionsTable::initialize(max_regions);
413 }
415 static void invalidate(uint start_idx, uint num_regions) {
416 OtherRegionsTable::invalidate(start_idx, num_regions);
417 }
419 #ifndef PRODUCT
420 static void print_from_card_cache() {
421 OtherRegionsTable::print_from_card_cache();
422 }
423 #endif
425 static void record(HeapRegion* hr, OopOrNarrowOopStar f);
426 static void print_recorded();
427 static void record_event(Event evnt);
429 // These are wrappers for the similarly-named methods on
430 // SparsePRT. Look at sparsePRT.hpp for more details.
431 static void reset_for_cleanup_tasks();
432 void do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task);
433 static void finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task);
435 // Run unit tests.
436 #ifndef PRODUCT
437 static void test_prt();
438 static void test();
439 #endif
440 };
442 class HeapRegionRemSetIterator : public StackObj {
443 private:
444 // The region RSet over which we are iterating.
445 HeapRegionRemSet* _hrrs;
447 // Local caching of HRRS fields.
448 const BitMap* _coarse_map;
450 G1BlockOffsetSharedArray* _bosa;
451 G1CollectedHeap* _g1h;
453 // The number of cards yielded since initialization.
454 size_t _n_yielded_fine;
455 size_t _n_yielded_coarse;
456 size_t _n_yielded_sparse;
458 // Indicates what granularity of table that we are currently iterating over.
459 // We start iterating over the sparse table, progress to the fine grain
460 // table, and then finish with the coarse table.
461 enum IterState {
462 Sparse,
463 Fine,
464 Coarse
465 };
466 IterState _is;
468 // For both Coarse and Fine remembered set iteration this contains the
469 // first card number of the heap region we currently iterate over.
470 size_t _cur_region_card_offset;
472 // Current region index for the Coarse remembered set iteration.
473 int _coarse_cur_region_index;
474 size_t _coarse_cur_region_cur_card;
476 bool coarse_has_next(size_t& card_index);
478 // The PRT we are currently iterating over.
479 PerRegionTable* _fine_cur_prt;
480 // Card offset within the current PRT.
481 size_t _cur_card_in_prt;
483 // Update internal variables when switching to the given PRT.
484 void switch_to_prt(PerRegionTable* prt);
485 bool fine_has_next();
486 bool fine_has_next(size_t& card_index);
488 // The Sparse remembered set iterator.
489 SparsePRTIter _sparse_iter;
491 public:
492 HeapRegionRemSetIterator(HeapRegionRemSet* hrrs);
494 // If there remains one or more cards to be yielded, returns true and
495 // sets "card_index" to one of those cards (which is then considered
496 // yielded.) Otherwise, returns false (and leaves "card_index"
497 // undefined.)
498 bool has_next(size_t& card_index);
500 size_t n_yielded_fine() { return _n_yielded_fine; }
501 size_t n_yielded_coarse() { return _n_yielded_coarse; }
502 size_t n_yielded_sparse() { return _n_yielded_sparse; }
503 size_t n_yielded() {
504 return n_yielded_fine() + n_yielded_coarse() + n_yielded_sparse();
505 }
506 };
508 #endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP