1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/src/share/vm/gc_implementation/g1/heapRegionRemSet.hpp Wed Apr 27 01:25:04 2016 +0800
1.3 @@ -0,0 +1,511 @@
1.4 +/*
1.5 + * Copyright (c) 2001, 2014, Oracle and/or its affiliates. All rights reserved.
1.6 + * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
1.7 + *
1.8 + * This code is free software; you can redistribute it and/or modify it
1.9 + * under the terms of the GNU General Public License version 2 only, as
1.10 + * published by the Free Software Foundation.
1.11 + *
1.12 + * This code is distributed in the hope that it will be useful, but WITHOUT
1.13 + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
1.14 + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
1.15 + * version 2 for more details (a copy is included in the LICENSE file that
1.16 + * accompanied this code).
1.17 + *
1.18 + * You should have received a copy of the GNU General Public License version
1.19 + * 2 along with this work; if not, write to the Free Software Foundation,
1.20 + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
1.21 + *
1.22 + * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
1.23 + * or visit www.oracle.com if you need additional information or have any
1.24 + * questions.
1.25 + *
1.26 + */
1.27 +
1.28 +#ifndef SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP
1.29 +#define SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP
1.30 +
1.31 +#include "gc_implementation/g1/g1CodeCacheRemSet.hpp"
1.32 +#include "gc_implementation/g1/sparsePRT.hpp"
1.33 +
1.34 +// Remembered set for a heap region. Represent a set of "cards" that
1.35 +// contain pointers into the owner heap region. Cards are defined somewhat
1.36 +// abstractly, in terms of what the "BlockOffsetTable" in use can parse.
1.37 +
1.38 +class G1CollectedHeap;
1.39 +class G1BlockOffsetSharedArray;
1.40 +class HeapRegion;
1.41 +class HeapRegionRemSetIterator;
1.42 +class PerRegionTable;
1.43 +class SparsePRT;
1.44 +class nmethod;
1.45 +
1.46 +// Essentially a wrapper around SparsePRTCleanupTask. See
1.47 +// sparsePRT.hpp for more details.
1.48 +class HRRSCleanupTask : public SparsePRTCleanupTask {
1.49 +};
1.50 +
1.51 +// The FromCardCache remembers the most recently processed card on the heap on
1.52 +// a per-region and per-thread basis.
1.53 +class FromCardCache : public AllStatic {
1.54 + private:
1.55 + // Array of card indices. Indexed by thread X and heap region to minimize
1.56 + // thread contention.
1.57 + static int** _cache;
1.58 + static uint _max_regions;
1.59 + static size_t _static_mem_size;
1.60 +
1.61 + public:
1.62 + enum {
1.63 + InvalidCard = -1 // Card value of an invalid card, i.e. a card index not otherwise used.
1.64 + };
1.65 +
1.66 + static void clear(uint region_idx);
1.67 +
1.68 + // Returns true if the given card is in the cache at the given location, or
1.69 + // replaces the card at that location and returns false.
1.70 + static bool contains_or_replace(uint worker_id, uint region_idx, int card) {
1.71 + int card_in_cache = at(worker_id, region_idx);
1.72 + if (card_in_cache == card) {
1.73 + return true;
1.74 + } else {
1.75 + set(worker_id, region_idx, card);
1.76 + return false;
1.77 + }
1.78 + }
1.79 +
1.80 + static int at(uint worker_id, uint region_idx) {
1.81 + return _cache[worker_id][region_idx];
1.82 + }
1.83 +
1.84 + static void set(uint worker_id, uint region_idx, int val) {
1.85 + _cache[worker_id][region_idx] = val;
1.86 + }
1.87 +
1.88 + static void initialize(uint n_par_rs, uint max_num_regions);
1.89 +
1.90 + static void shrink(uint new_num_regions);
1.91 +
1.92 + static void print(outputStream* out = gclog_or_tty) PRODUCT_RETURN;
1.93 +
1.94 + static size_t static_mem_size() {
1.95 + return _static_mem_size;
1.96 + }
1.97 +};
1.98 +
1.99 +// The "_coarse_map" is a bitmap with one bit for each region, where set
1.100 +// bits indicate that the corresponding region may contain some pointer
1.101 +// into the owning region.
1.102 +
1.103 +// The "_fine_grain_entries" array is an open hash table of PerRegionTables
1.104 +// (PRTs), indicating regions for which we're keeping the RS as a set of
1.105 +// cards. The strategy is to cap the size of the fine-grain table,
1.106 +// deleting an entry and setting the corresponding coarse-grained bit when
1.107 +// we would overflow this cap.
1.108 +
1.109 +// We use a mixture of locking and lock-free techniques here. We allow
1.110 +// threads to locate PRTs without locking, but threads attempting to alter
1.111 +// a bucket list obtain a lock. This means that any failing attempt to
1.112 +// find a PRT must be retried with the lock. It might seem dangerous that
1.113 +// a read can find a PRT that is concurrently deleted. This is all right,
1.114 +// because:
1.115 +//
1.116 +// 1) We only actually free PRT's at safe points (though we reuse them at
1.117 +// other times).
1.118 +// 2) We find PRT's in an attempt to add entries. If a PRT is deleted,
1.119 +// it's _coarse_map bit is set, so the that we were attempting to add
1.120 +// is represented. If a deleted PRT is re-used, a thread adding a bit,
1.121 +// thinking the PRT is for a different region, does no harm.
1.122 +
1.123 +class OtherRegionsTable VALUE_OBJ_CLASS_SPEC {
1.124 + friend class HeapRegionRemSetIterator;
1.125 +
1.126 + G1CollectedHeap* _g1h;
1.127 + Mutex* _m;
1.128 + HeapRegion* _hr;
1.129 +
1.130 + // These are protected by "_m".
1.131 + BitMap _coarse_map;
1.132 + size_t _n_coarse_entries;
1.133 + static jint _n_coarsenings;
1.134 +
1.135 + PerRegionTable** _fine_grain_regions;
1.136 + size_t _n_fine_entries;
1.137 +
1.138 + // The fine grain remembered sets are doubly linked together using
1.139 + // their 'next' and 'prev' fields.
1.140 + // This allows fast bulk freeing of all the fine grain remembered
1.141 + // set entries, and fast finding of all of them without iterating
1.142 + // over the _fine_grain_regions table.
1.143 + PerRegionTable * _first_all_fine_prts;
1.144 + PerRegionTable * _last_all_fine_prts;
1.145 +
1.146 + // Used to sample a subset of the fine grain PRTs to determine which
1.147 + // PRT to evict and coarsen.
1.148 + size_t _fine_eviction_start;
1.149 + static size_t _fine_eviction_stride;
1.150 + static size_t _fine_eviction_sample_size;
1.151 +
1.152 + SparsePRT _sparse_table;
1.153 +
1.154 + // These are static after init.
1.155 + static size_t _max_fine_entries;
1.156 + static size_t _mod_max_fine_entries_mask;
1.157 +
1.158 + // Requires "prt" to be the first element of the bucket list appropriate
1.159 + // for "hr". If this list contains an entry for "hr", return it,
1.160 + // otherwise return "NULL".
1.161 + PerRegionTable* find_region_table(size_t ind, HeapRegion* hr) const;
1.162 +
1.163 + // Find, delete, and return a candidate PerRegionTable, if any exists,
1.164 + // adding the deleted region to the coarse bitmap. Requires the caller
1.165 + // to hold _m, and the fine-grain table to be full.
1.166 + PerRegionTable* delete_region_table();
1.167 +
1.168 + // If a PRT for "hr" is in the bucket list indicated by "ind" (which must
1.169 + // be the correct index for "hr"), delete it and return true; else return
1.170 + // false.
1.171 + bool del_single_region_table(size_t ind, HeapRegion* hr);
1.172 +
1.173 + // link/add the given fine grain remembered set into the "all" list
1.174 + void link_to_all(PerRegionTable * prt);
1.175 + // unlink/remove the given fine grain remembered set into the "all" list
1.176 + void unlink_from_all(PerRegionTable * prt);
1.177 +
1.178 +public:
1.179 + OtherRegionsTable(HeapRegion* hr, Mutex* m);
1.180 +
1.181 + HeapRegion* hr() const { return _hr; }
1.182 +
1.183 + // For now. Could "expand" some tables in the future, so that this made
1.184 + // sense.
1.185 + void add_reference(OopOrNarrowOopStar from, int tid);
1.186 +
1.187 + // Removes any entries shown by the given bitmaps to contain only dead
1.188 + // objects.
1.189 + void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm);
1.190 +
1.191 + size_t occupied() const;
1.192 + size_t occ_fine() const;
1.193 + size_t occ_coarse() const;
1.194 + size_t occ_sparse() const;
1.195 +
1.196 + static jint n_coarsenings() { return _n_coarsenings; }
1.197 +
1.198 + // Returns size in bytes.
1.199 + // Not const because it takes a lock.
1.200 + size_t mem_size() const;
1.201 + static size_t static_mem_size();
1.202 + static size_t fl_mem_size();
1.203 +
1.204 + bool contains_reference(OopOrNarrowOopStar from) const;
1.205 + bool contains_reference_locked(OopOrNarrowOopStar from) const;
1.206 +
1.207 + void clear();
1.208 +
1.209 + // Specifically clear the from_card_cache.
1.210 + void clear_fcc();
1.211 +
1.212 + // "from_hr" is being cleared; remove any entries from it.
1.213 + void clear_incoming_entry(HeapRegion* from_hr);
1.214 +
1.215 + void do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task);
1.216 +
1.217 + // Declare the heap size (in # of regions) to the OtherRegionsTable.
1.218 + // (Uses it to initialize from_card_cache).
1.219 + static void init_from_card_cache(uint max_regions);
1.220 +
1.221 + // Declares that only regions i s.t. 0 <= i < new_n_regs are in use.
1.222 + // Make sure any entries for higher regions are invalid.
1.223 + static void shrink_from_card_cache(uint new_num_regions);
1.224 +
1.225 + static void print_from_card_cache();
1.226 +};
1.227 +
1.228 +class HeapRegionRemSet : public CHeapObj<mtGC> {
1.229 + friend class VMStructs;
1.230 + friend class HeapRegionRemSetIterator;
1.231 +
1.232 +public:
1.233 + enum Event {
1.234 + Event_EvacStart, Event_EvacEnd, Event_RSUpdateEnd
1.235 + };
1.236 +
1.237 +private:
1.238 + G1BlockOffsetSharedArray* _bosa;
1.239 + G1BlockOffsetSharedArray* bosa() const { return _bosa; }
1.240 +
1.241 + // A set of code blobs (nmethods) whose code contains pointers into
1.242 + // the region that owns this RSet.
1.243 + G1CodeRootSet _code_roots;
1.244 +
1.245 + Mutex _m;
1.246 +
1.247 + OtherRegionsTable _other_regions;
1.248 +
1.249 + enum ParIterState { Unclaimed, Claimed, Complete };
1.250 + volatile ParIterState _iter_state;
1.251 + volatile jlong _iter_claimed;
1.252 +
1.253 + // Unused unless G1RecordHRRSOops is true.
1.254 +
1.255 + static const int MaxRecorded = 1000000;
1.256 + static OopOrNarrowOopStar* _recorded_oops;
1.257 + static HeapWord** _recorded_cards;
1.258 + static HeapRegion** _recorded_regions;
1.259 + static int _n_recorded;
1.260 +
1.261 + static const int MaxRecordedEvents = 1000;
1.262 + static Event* _recorded_events;
1.263 + static int* _recorded_event_index;
1.264 + static int _n_recorded_events;
1.265 +
1.266 + static void print_event(outputStream* str, Event evnt);
1.267 +
1.268 +public:
1.269 + HeapRegionRemSet(G1BlockOffsetSharedArray* bosa, HeapRegion* hr);
1.270 +
1.271 + static uint num_par_rem_sets();
1.272 + static void setup_remset_size();
1.273 +
1.274 + HeapRegion* hr() const {
1.275 + return _other_regions.hr();
1.276 + }
1.277 +
1.278 + size_t occupied() {
1.279 + MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
1.280 + return occupied_locked();
1.281 + }
1.282 + size_t occupied_locked() {
1.283 + return _other_regions.occupied();
1.284 + }
1.285 + size_t occ_fine() const {
1.286 + return _other_regions.occ_fine();
1.287 + }
1.288 + size_t occ_coarse() const {
1.289 + return _other_regions.occ_coarse();
1.290 + }
1.291 + size_t occ_sparse() const {
1.292 + return _other_regions.occ_sparse();
1.293 + }
1.294 +
1.295 + static jint n_coarsenings() { return OtherRegionsTable::n_coarsenings(); }
1.296 +
1.297 + // Used in the sequential case.
1.298 + void add_reference(OopOrNarrowOopStar from) {
1.299 + _other_regions.add_reference(from, 0);
1.300 + }
1.301 +
1.302 + // Used in the parallel case.
1.303 + void add_reference(OopOrNarrowOopStar from, int tid) {
1.304 + _other_regions.add_reference(from, tid);
1.305 + }
1.306 +
1.307 + // Removes any entries shown by the given bitmaps to contain only dead
1.308 + // objects.
1.309 + void scrub(CardTableModRefBS* ctbs, BitMap* region_bm, BitMap* card_bm);
1.310 +
1.311 + // The region is being reclaimed; clear its remset, and any mention of
1.312 + // entries for this region in other remsets.
1.313 + void clear();
1.314 + void clear_locked();
1.315 +
1.316 + // Attempt to claim the region. Returns true iff this call caused an
1.317 + // atomic transition from Unclaimed to Claimed.
1.318 + bool claim_iter();
1.319 + // Sets the iteration state to "complete".
1.320 + void set_iter_complete();
1.321 + // Returns "true" iff the region's iteration is complete.
1.322 + bool iter_is_complete();
1.323 +
1.324 + // Support for claiming blocks of cards during iteration
1.325 + size_t iter_claimed() const { return (size_t)_iter_claimed; }
1.326 + // Claim the next block of cards
1.327 + size_t iter_claimed_next(size_t step) {
1.328 + size_t current, next;
1.329 + do {
1.330 + current = iter_claimed();
1.331 + next = current + step;
1.332 + } while (Atomic::cmpxchg((jlong)next, &_iter_claimed, (jlong)current) != (jlong)current);
1.333 + return current;
1.334 + }
1.335 + void reset_for_par_iteration();
1.336 +
1.337 + bool verify_ready_for_par_iteration() {
1.338 + return (_iter_state == Unclaimed) && (_iter_claimed == 0);
1.339 + }
1.340 +
1.341 + // The actual # of bytes this hr_remset takes up.
1.342 + // Note also includes the strong code root set.
1.343 + size_t mem_size() {
1.344 + MutexLockerEx x(&_m, Mutex::_no_safepoint_check_flag);
1.345 + return _other_regions.mem_size()
1.346 + // This correction is necessary because the above includes the second
1.347 + // part.
1.348 + + (sizeof(this) - sizeof(OtherRegionsTable))
1.349 + + strong_code_roots_mem_size();
1.350 + }
1.351 +
1.352 + // Returns the memory occupancy of all static data structures associated
1.353 + // with remembered sets.
1.354 + static size_t static_mem_size() {
1.355 + return OtherRegionsTable::static_mem_size() + G1CodeRootSet::static_mem_size();
1.356 + }
1.357 +
1.358 + // Returns the memory occupancy of all free_list data structures associated
1.359 + // with remembered sets.
1.360 + static size_t fl_mem_size() {
1.361 + return OtherRegionsTable::fl_mem_size() + G1CodeRootSet::fl_mem_size();
1.362 + }
1.363 +
1.364 + bool contains_reference(OopOrNarrowOopStar from) const {
1.365 + return _other_regions.contains_reference(from);
1.366 + }
1.367 +
1.368 + // Routines for managing the list of code roots that point into
1.369 + // the heap region that owns this RSet.
1.370 + void add_strong_code_root(nmethod* nm);
1.371 + void remove_strong_code_root(nmethod* nm);
1.372 +
1.373 + // During a collection, migrate the successfully evacuated strong
1.374 + // code roots that referenced into the region that owns this RSet
1.375 + // to the RSets of the new regions that they now point into.
1.376 + // Unsuccessfully evacuated code roots are not migrated.
1.377 + void migrate_strong_code_roots();
1.378 +
1.379 + // Applies blk->do_code_blob() to each of the entries in
1.380 + // the strong code roots list
1.381 + void strong_code_roots_do(CodeBlobClosure* blk) const;
1.382 +
1.383 + // Returns the number of elements in the strong code roots list
1.384 + size_t strong_code_roots_list_length() {
1.385 + return _code_roots.length();
1.386 + }
1.387 +
1.388 + // Returns true if the strong code roots contains the given
1.389 + // nmethod.
1.390 + bool strong_code_roots_list_contains(nmethod* nm) {
1.391 + return _code_roots.contains(nm);
1.392 + }
1.393 +
1.394 + // Returns the amount of memory, in bytes, currently
1.395 + // consumed by the strong code roots.
1.396 + size_t strong_code_roots_mem_size();
1.397 +
1.398 + void print() PRODUCT_RETURN;
1.399 +
1.400 + // Called during a stop-world phase to perform any deferred cleanups.
1.401 + static void cleanup();
1.402 +
1.403 + // Declare the heap size (in # of regions) to the HeapRegionRemSet(s).
1.404 + // (Uses it to initialize from_card_cache).
1.405 + static void init_heap(uint max_regions) {
1.406 + G1CodeRootSet::initialize();
1.407 + OtherRegionsTable::init_from_card_cache(max_regions);
1.408 + }
1.409 +
1.410 + // Declares that only regions i s.t. 0 <= i < new_n_regs are in use.
1.411 + static void shrink_heap(uint new_n_regs) {
1.412 + OtherRegionsTable::shrink_from_card_cache(new_n_regs);
1.413 + }
1.414 +
1.415 +#ifndef PRODUCT
1.416 + static void print_from_card_cache() {
1.417 + OtherRegionsTable::print_from_card_cache();
1.418 + }
1.419 +#endif
1.420 +
1.421 + static void record(HeapRegion* hr, OopOrNarrowOopStar f);
1.422 + static void print_recorded();
1.423 + static void record_event(Event evnt);
1.424 +
1.425 + // These are wrappers for the similarly-named methods on
1.426 + // SparsePRT. Look at sparsePRT.hpp for more details.
1.427 + static void reset_for_cleanup_tasks();
1.428 + void do_cleanup_work(HRRSCleanupTask* hrrs_cleanup_task);
1.429 + static void finish_cleanup_task(HRRSCleanupTask* hrrs_cleanup_task);
1.430 +
1.431 + // Run unit tests.
1.432 +#ifndef PRODUCT
1.433 + static void test_prt();
1.434 + static void test();
1.435 +#endif
1.436 +};
1.437 +
1.438 +class HeapRegionRemSetIterator : public StackObj {
1.439 +
1.440 + // The region RSet over which we're iterating.
1.441 + HeapRegionRemSet* _hrrs;
1.442 +
1.443 + // Local caching of HRRS fields.
1.444 + const BitMap* _coarse_map;
1.445 + PerRegionTable** _fine_grain_regions;
1.446 +
1.447 + G1BlockOffsetSharedArray* _bosa;
1.448 + G1CollectedHeap* _g1h;
1.449 +
1.450 + // The number yielded since initialization.
1.451 + size_t _n_yielded_fine;
1.452 + size_t _n_yielded_coarse;
1.453 + size_t _n_yielded_sparse;
1.454 +
1.455 + // Indicates what granularity of table that we're currently iterating over.
1.456 + // We start iterating over the sparse table, progress to the fine grain
1.457 + // table, and then finish with the coarse table.
1.458 + // See HeapRegionRemSetIterator::has_next().
1.459 + enum IterState {
1.460 + Sparse,
1.461 + Fine,
1.462 + Coarse
1.463 + };
1.464 + IterState _is;
1.465 +
1.466 + // In both kinds of iteration, heap offset of first card of current
1.467 + // region.
1.468 + size_t _cur_region_card_offset;
1.469 + // Card offset within cur region.
1.470 + size_t _cur_region_cur_card;
1.471 +
1.472 + // Coarse table iteration fields:
1.473 +
1.474 + // Current region index;
1.475 + int _coarse_cur_region_index;
1.476 + size_t _coarse_cur_region_cur_card;
1.477 +
1.478 + bool coarse_has_next(size_t& card_index);
1.479 +
1.480 + // Fine table iteration fields:
1.481 +
1.482 + // Index of bucket-list we're working on.
1.483 + int _fine_array_index;
1.484 +
1.485 + // Per Region Table we're doing within current bucket list.
1.486 + PerRegionTable* _fine_cur_prt;
1.487 +
1.488 + /* SparsePRT::*/ SparsePRTIter _sparse_iter;
1.489 +
1.490 + void fine_find_next_non_null_prt();
1.491 +
1.492 + bool fine_has_next();
1.493 + bool fine_has_next(size_t& card_index);
1.494 +
1.495 +public:
1.496 + // We require an iterator to be initialized before use, so the
1.497 + // constructor does little.
1.498 + HeapRegionRemSetIterator(HeapRegionRemSet* hrrs);
1.499 +
1.500 + // If there remains one or more cards to be yielded, returns true and
1.501 + // sets "card_index" to one of those cards (which is then considered
1.502 + // yielded.) Otherwise, returns false (and leaves "card_index"
1.503 + // undefined.)
1.504 + bool has_next(size_t& card_index);
1.505 +
1.506 + size_t n_yielded_fine() { return _n_yielded_fine; }
1.507 + size_t n_yielded_coarse() { return _n_yielded_coarse; }
1.508 + size_t n_yielded_sparse() { return _n_yielded_sparse; }
1.509 + size_t n_yielded() {
1.510 + return n_yielded_fine() + n_yielded_coarse() + n_yielded_sparse();
1.511 + }
1.512 +};
1.513 +
1.514 +#endif // SHARE_VM_GC_IMPLEMENTATION_G1_HEAPREGIONREMSET_HPP
