PMDK C++ bindings  1.13.0-git107.g7e59f08f
This is the C++ bindings documentation for PMDK's libpmemobj.
concurrent_hash_map.hpp
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1 // SPDX-License-Identifier: BSD-3-Clause
2 /* Copyright 2019-2021, Intel Corporation */
3 
10 #ifndef PMEMOBJ_CONCURRENT_HASH_MAP_HPP
11 #define PMEMOBJ_CONCURRENT_HASH_MAP_HPP
12 
17 
18 #include <libpmemobj++/defrag.hpp>
20 #include <libpmemobj++/mutex.hpp>
21 #include <libpmemobj++/p.hpp>
24 
27 
29 
30 #include <atomic>
31 #include <cassert>
32 #include <functional>
33 #include <initializer_list>
34 #include <iterator> // for std::distance
35 #include <memory>
36 #include <mutex>
37 #include <thread>
38 #include <type_traits>
39 #include <utility>
40 #include <vector>
41 
42 namespace std
43 {
47 template <typename T>
48 struct hash<pmem::obj::p<T>> {
49  size_t
50  operator()(const pmem::obj::p<T> &x) const
51  {
52  return hash<T>()(x.get_ro());
53  }
54 };
55 } /* namespace std */
56 
57 namespace pmem
58 {
59 namespace obj
60 {
61 
62 namespace concurrent_hash_map_internal
63 {
64 template <typename SharedMutexT>
65 class shared_mutex_scoped_lock {
66  using rw_mutex_type = SharedMutexT;
67 
68 public:
69  shared_mutex_scoped_lock(const shared_mutex_scoped_lock &) = delete;
70  shared_mutex_scoped_lock &
71  operator=(const shared_mutex_scoped_lock &) = delete;
72 
74  shared_mutex_scoped_lock() : mutex(nullptr), is_writer(false)
75  {
76  }
77 
79  shared_mutex_scoped_lock(rw_mutex_type &m, bool write = true)
80  : mutex(nullptr)
81  {
82  acquire(m, write);
83  }
84 
86  ~shared_mutex_scoped_lock()
87  {
88  if (mutex)
89  release();
90  }
91 
93  void
94  acquire(rw_mutex_type &m, bool write = true)
95  {
96  is_writer = write;
97  mutex = &m;
98  if (write)
99  mutex->lock();
100  else
101  mutex->lock_shared();
102  }
103 
107  void
108  release()
109  {
110  assert(mutex);
111  rw_mutex_type *m = mutex;
112  mutex = nullptr;
113  if (is_writer) {
114  m->unlock();
115  } else {
116  m->unlock_shared();
117  }
118  }
119 
124  bool
125  try_acquire(rw_mutex_type &m, bool write = true)
126  {
127  assert(!mutex);
128  bool result;
129  is_writer = write;
130  result = write ? m.try_lock() : m.try_lock_shared();
131  if (result)
132  mutex = &m;
133  return result;
134  }
135 
136 protected:
141  rw_mutex_type *mutex;
146  bool is_writer;
147 }; /* class shared_mutex_scoped_lock */
148 
149 template <typename ScopedLockType>
150 using scoped_lock_upgrade_to_writer =
151  decltype(std::declval<ScopedLockType>().upgrade_to_writer());
152 
153 template <typename ScopedLockType>
154 using scoped_lock_has_upgrade_to_writer =
155  detail::supports<ScopedLockType, scoped_lock_upgrade_to_writer>;
156 
157 template <typename ScopedLockType>
158 using scoped_lock_downgrade_to_reader =
159  decltype(std::declval<ScopedLockType>().downgrade_to_reader());
160 
161 template <typename ScopedLockType>
162 using scoped_lock_has_downgrade_to_reader =
163  detail::supports<ScopedLockType, scoped_lock_downgrade_to_reader>;
164 
165 template <typename ScopedLockType,
166  bool = scoped_lock_has_upgrade_to_writer<ScopedLockType>::value
167  &&scoped_lock_has_downgrade_to_reader<ScopedLockType>::value>
168 class scoped_lock_traits {
169 public:
170  using scope_lock_type = ScopedLockType;
171 
172  static bool
173  initial_rw_state(bool write)
174  {
175  /* For upgradeable locks, initial state is always read */
176  return false;
177  }
178 
179  static bool
180  upgrade_to_writer(scope_lock_type &lock)
181  {
182  return lock.upgrade_to_writer();
183  }
184 
185  static bool
186  downgrade_to_reader(scope_lock_type &lock)
187  {
188  return lock.downgrade_to_reader();
189  }
190 };
191 
192 template <typename ScopedLockType>
193 class scoped_lock_traits<ScopedLockType, false> {
194 public:
195  using scope_lock_type = ScopedLockType;
196 
197  static bool
198  initial_rw_state(bool write)
199  {
200  /* For non-upgradeable locks, we take lock in required mode
201  * immediately */
202  return write;
203  }
204 
205  static bool
206  upgrade_to_writer(scope_lock_type &lock)
207  {
208  /* This overload is for locks which do not support upgrade
209  * operation. For those locks, upgrade_to_writer should not be
210  * called when holding a read lock */
211  return true;
212  }
213 
214  static bool
215  downgrade_to_reader(scope_lock_type &lock)
216  {
217  /* This overload is for locks which do not support downgrade
218  * operation. For those locks, downgrade_to_reader should never
219  * be called */
220  assert(false);
221 
222  return false;
223  }
224 };
225 } /* namespace concurrent_hash_map_internal */
226 
227 template <typename Key, typename T, typename Hash = std::hash<Key>,
228  typename KeyEqual = std::equal_to<Key>,
229  typename MutexType = pmem::obj::shared_mutex,
230  typename ScopedLockType = concurrent_hash_map_internal::
231  shared_mutex_scoped_lock<MutexType>>
232 class concurrent_hash_map;
233 
235 namespace concurrent_hash_map_internal
236 {
237 /* Helper method which throws an exception when called in a tx */
238 static inline void
239 check_outside_tx()
240 {
241  if (pmemobj_tx_stage() != TX_STAGE_NONE)
243  "Function called inside transaction scope.");
244 }
245 
246 template <typename Hash>
247 using transparent_key_equal = typename Hash::transparent_key_equal;
248 
249 template <typename Hash>
250 using has_transparent_key_equal = detail::supports<Hash, transparent_key_equal>;
251 
252 template <typename Hash, typename Pred,
253  bool = has_transparent_key_equal<Hash>::value>
254 struct key_equal_type {
255  using type = typename Hash::transparent_key_equal;
256 };
257 
258 template <typename Hash, typename Pred>
259 struct key_equal_type<Hash, Pred, false> {
260  using type = Pred;
261 };
262 
263 template <typename Mutex, typename ScopedLockType>
264 void
265 assert_not_locked(Mutex &mtx)
266 {
267 #ifndef NDEBUG
268  ScopedLockType scoped_lock;
269  assert(scoped_lock.try_acquire(mtx));
270  scoped_lock.release();
271 #else
272  (void)mtx;
273 #endif
274 }
275 
276 template <typename Key, typename T, typename MutexType, typename ScopedLockType>
277 struct hash_map_node {
279  using mutex_t = MutexType;
280 
282  using scoped_t = ScopedLockType;
283 
284  using value_type = detail::pair<const Key, T>;
285 
287  using node_ptr_t = detail::persistent_pool_ptr<
288  hash_map_node<Key, T, mutex_t, scoped_t>>;
289 
291  node_ptr_t next;
292 
294  mutex_t mutex;
295 
297  value_type item;
298 
299  hash_map_node(const node_ptr_t &_next, const Key &key)
300  : next(_next),
301  item(std::piecewise_construct, std::forward_as_tuple(key),
302  std::forward_as_tuple())
303  {
304  }
305 
306  hash_map_node(const node_ptr_t &_next, const Key &key, const T &t)
307  : next(_next), item(key, t)
308  {
309  }
310 
311  hash_map_node(const node_ptr_t &_next, value_type &&i)
312  : next(_next), item(std::move(i))
313  {
314  }
315 
316  template <typename... Args>
317  hash_map_node(const node_ptr_t &_next, Args &&... args)
318  : next(_next), item(std::forward<Args>(args)...)
319  {
320  }
321 
322  hash_map_node(const node_ptr_t &_next, const value_type &i)
323  : next(_next), item(i)
324  {
325  }
326 
328  hash_map_node(const hash_map_node &) = delete;
329 
331  hash_map_node &operator=(const hash_map_node &) = delete;
332 }; /* struct node */
333 
338 template <typename Bucket>
339 class segment_traits {
340 public:
342  using segment_index_t = size_t;
343  using size_type = size_t;
344  using bucket_type = Bucket;
345 
346 protected:
348  constexpr static size_type max_allocation_size = PMEMOBJ_MAX_ALLOC_SIZE;
349 
351  constexpr static segment_index_t first_big_block = 27;
352  /* TODO: avoid hardcoded value; need constexpr similar to:
353  * Log2(max_allocation_size / sizeof(bucket_type)) */
354 
356  constexpr static size_type big_block_size = size_type(1)
357  << first_big_block;
358 
359  /* Block size in bytes cannot exceed max_allocation_size */
360  static_assert((big_block_size * sizeof(bucket_type)) <
361  max_allocation_size,
362  "Block size exceeds max_allocation_size");
363 
365  constexpr static segment_index_t
366  first_block_in_segment(segment_index_t seg)
367  {
368  return seg < first_big_block
369  ? seg
370  : (first_big_block +
371  (segment_index_t(1) << (seg - first_big_block)) - 1);
372  }
373 
375  constexpr static size_type
376  blocks_in_segment(segment_index_t seg)
377  {
378  return seg < first_big_block
379  ? segment_index_t(1)
380  : segment_index_t(1) << (seg - first_big_block);
381  }
382 
384  constexpr static size_type
385  block_size(segment_index_t b)
386  {
387  return b < first_big_block ? segment_size(b ? b : 1)
388  : big_block_size;
389  }
390 
391 public:
393  constexpr static segment_index_t embedded_segments = 1;
394 
396  constexpr static size_type embedded_buckets = 1 << embedded_segments;
397 
399  constexpr static segment_index_t number_of_segments = 32;
400 
402  static const size_type first_block = 8;
403 
405  constexpr static segment_index_t
406  number_of_blocks()
407  {
408  return first_block_in_segment(number_of_segments);
409  }
410 
412  static segment_index_t
413  segment_index_of(size_type index)
414  {
415  return segment_index_t(detail::Log2(index | 1));
416  }
417 
419  constexpr static segment_index_t
420  segment_base(segment_index_t k)
421  {
422  return (segment_index_t(1) << k) & ~segment_index_t(1);
423  }
424 
426  constexpr static size_type
427  segment_size(segment_index_t k)
428  {
429  return size_type(1) << k; // fake value for k == 0
430  }
431  static_assert(
432  embedded_segments < first_big_block,
433  "Number of embedded segments cannot exceed max_allocation_size");
434 }; /* End of class segment_traits */
435 
452 template <typename BlockTable, typename SegmentTraits, bool is_const>
453 class segment_facade_impl : public SegmentTraits {
454 private:
455  using traits_type = SegmentTraits;
456  using traits_type::block_size;
457  using traits_type::blocks_in_segment;
458  using traits_type::embedded_buckets;
459  using traits_type::embedded_segments;
460  using traits_type::first_block;
461  using traits_type::first_block_in_segment;
462  using traits_type::segment_base;
463  using traits_type::segment_size;
464 
465 public:
466  using table_reference =
467  typename std::conditional<is_const, const BlockTable &,
468  BlockTable &>::type;
469 
470  using table_pointer =
471  typename std::conditional<is_const, const BlockTable *,
472  BlockTable *>::type;
473 
474  using bucket_type = typename traits_type::bucket_type;
475  using segment_index_t = typename traits_type::segment_index_t;
476  using size_type = typename traits_type::size_type;
477 
479  segment_facade_impl(table_reference table, segment_index_t s)
480  : my_table(&table), my_seg(s)
481  {
482  assert(my_seg < traits_type::number_of_segments);
483  }
484 
486  segment_facade_impl(const segment_facade_impl &src)
487  : my_table(src.my_table), my_seg(src.my_seg)
488  {
489  }
490 
491  segment_facade_impl(segment_facade_impl &&src) = default;
492 
494  segment_facade_impl &
495  operator=(const segment_facade_impl &src)
496  {
497  my_table = src.my_table;
498  my_seg = src.my_seg;
499  return *this;
500  }
501 
503  segment_facade_impl &
504  operator=(segment_facade_impl &&src)
505  {
506  my_table = src.my_table;
507  my_seg = src.my_seg;
508  return *this;
509  }
510 
517  bucket_type &operator[](size_type i) const
518  {
519  assert(i < size());
520 
521  segment_index_t table_block = first_block_in_segment(my_seg);
522  size_type b_size = block_size(table_block);
523 
524  table_block += i / b_size;
525  i = i % b_size;
526 
527  return (*my_table)[table_block][static_cast<std::ptrdiff_t>(i)];
528  }
529 
533  segment_facade_impl &
534  operator++()
535  {
536  ++my_seg;
537  return *this;
538  }
539 
543  segment_facade_impl
544  operator++(int)
545  {
546  segment_facade_impl tmp = *this;
547  ++(*this);
548  return tmp;
549  }
550 
554  segment_facade_impl &
555  operator--()
556  {
557  --my_seg;
558  return *this;
559  }
560 
564  segment_facade_impl
565  operator--(int)
566  {
567  segment_facade_impl tmp = *this;
568  --(*this);
569  return tmp;
570  }
571 
575  segment_facade_impl &
576  operator+=(segment_index_t off)
577  {
578  my_seg += off;
579  return *this;
580  }
581 
585  segment_facade_impl &
586  operator-=(segment_index_t off)
587  {
588  my_seg -= off;
589  return *this;
590  }
591 
595  segment_facade_impl
596  operator+(segment_index_t off) const
597  {
598  return segment_facade_impl(*(this->my_table),
599  this->my_seg + off);
600  }
601 
605  segment_facade_impl
606  operator-(segment_index_t off) const
607  {
608  return segment_facade_impl(*(this->my_table),
609  this->my_seg - off);
610  }
611 
615  void
616  enable(pool_base &pop)
617  {
618  assert(my_seg >= embedded_segments);
619 
620  if (my_seg < first_block) {
621  enable_first_block(pop);
622  } else {
623  enable_big_segment(pop);
624  }
625  }
626 
630  void
631  disable()
632  {
633  assert(my_seg >= embedded_segments);
634 
635  if (my_seg < first_block) {
636  if (my_seg == embedded_segments) {
637  size_type sz = segment_size(first_block) -
638  embedded_buckets;
639  delete_persistent<bucket_type[]>(
640  (*my_table)[my_seg], sz);
641  }
642  (*my_table)[my_seg] = nullptr;
643  } else {
644  block_range blocks = segment_blocks(my_seg);
645 
646  for (segment_index_t b = blocks.first;
647  b < blocks.second; ++b) {
648  if ((*my_table)[b] != nullptr) {
649  delete_persistent<bucket_type[]>(
650  (*my_table)[b], block_size(b));
651  (*my_table)[b] = nullptr;
652  }
653  }
654  }
655  }
656 
660  constexpr size_type
661  size() const
662  {
663  return segment_size(my_seg ? my_seg : 1);
664  }
665 
671  bool
672  is_valid() const
673  {
674  block_range blocks = segment_blocks(my_seg);
675 
676  for (segment_index_t b = blocks.first; b < blocks.second; ++b) {
677  if ((*my_table)[b] == nullptr)
678  return false;
679  }
680 
681  return true;
682  }
683 
684 private:
685  using block_range = std::pair<segment_index_t, segment_index_t>;
686 
690  static block_range
691  segment_blocks(segment_index_t seg)
692  {
693  segment_index_t begin = first_block_in_segment(seg);
694 
695  return block_range(begin, begin + blocks_in_segment(seg));
696  }
697 
698  void
699  enable_first_block(pool_base &pop)
700  {
701  assert(my_seg == embedded_segments);
702  {
703  flat_transaction::manual tx(pop);
704 
705  size_type sz =
706  segment_size(first_block) - embedded_buckets;
707  (*my_table)[my_seg] =
708  make_persistent<bucket_type[]>(sz);
709 
710  persistent_ptr<bucket_type> base =
711  (*my_table)[embedded_segments].raw();
712 
713  for (segment_index_t s = my_seg + 1; s < first_block;
714  ++s) {
715  std::ptrdiff_t off =
716  static_cast<std::ptrdiff_t>(
717  segment_base(s) -
718  segment_base(my_seg));
719 
720  (*my_table)[s] = (base + off).raw();
721  }
722 
724  }
725  }
726 
727  void
728  enable_big_segment(pool_base &pop)
729  {
730  block_range blocks = segment_blocks(my_seg);
731  {
732  flat_transaction::manual tx(pop);
733 
734  for (segment_index_t b = blocks.first;
735  b < blocks.second; ++b) {
736  assert((*my_table)[b] == nullptr);
737  (*my_table)[b] = make_persistent<bucket_type[]>(
738  block_size(b));
739  }
740 
742  }
743  }
744 
746  table_pointer my_table;
747 
749  segment_index_t my_seg;
750 }; /* End of class segment_facade_impl */
751 
758 template <typename Key, typename T, typename MutexType, typename ScopedLockType>
759 class hash_map_base {
760 public:
761  using mutex_t = MutexType;
762  using scoped_t = ScopedLockType;
763 
765  using size_type = size_t;
766 
768  using hashcode_type = size_t;
769 
771  using node = hash_map_node<Key, T, mutex_t, scoped_t>;
772 
774  using node_ptr_t = detail::persistent_pool_ptr<node>;
775 
777  struct bucket {
778  using mutex_t = MutexType;
779  using scoped_t = ScopedLockType;
780 
782  mutex_t mutex;
783 
785  p<std::atomic<uint64_t>> rehashed;
786 
788  node_ptr_t node_list;
789 
791  bucket() : node_list(nullptr)
792  {
793 #if LIBPMEMOBJ_CPP_VG_HELGRIND_ENABLED
794  VALGRIND_HG_DISABLE_CHECKING(&rehashed,
795  sizeof(rehashed));
796 #endif
797  rehashed.get_rw() = false;
798  }
799 
805  bool
806  is_rehashed(std::memory_order order)
807  {
808  return rehashed.get_ro().load(order);
809  }
810 
811  void
812  set_rehashed(std::memory_order order)
813  {
814  rehashed.get_rw().store(true, order);
815  }
816 
818  bucket(const bucket &) = delete;
819 
821  bucket &operator=(const bucket &) = delete;
822  }; /* End of struct bucket */
823 
825  using segment_traits_t = segment_traits<bucket>;
826 
828  using segment_index_t = typename segment_traits_t::segment_index_t;
829 
831  static const size_type embedded_buckets =
832  segment_traits_t::embedded_buckets;
833 
835  static const size_type first_block = segment_traits_t::first_block;
836 
838  constexpr static size_type block_table_size =
839  segment_traits_t::number_of_blocks();
840 
842  using segment_ptr_t = persistent_ptr<bucket[]>;
843 
845  using bucket_ptr_t = persistent_ptr<bucket>;
846 
848  using blocks_table_t = segment_ptr_t[block_table_size];
849 
851  using segment_enable_mutex_t = pmem::obj::mutex;
852 
854  struct tls_data_t {
855  p<int64_t> size_diff = 0;
856  std::aligned_storage<56, 8> padding;
857  };
858 
859  using tls_t = detail::enumerable_thread_specific<tls_data_t>;
860 
861  enum feature_flags : uint32_t { FEATURE_CONSISTENT_SIZE = 1 };
862 
864  struct features {
865  p<uint32_t> compat;
866  p<uint32_t> incompat;
867  };
868 
869  /* --------------------------------------------------------- */
870 
872  p<uint64_t> my_pool_uuid;
873 
876  features layout_features;
877 
880  std::aligned_storage<sizeof(size_t), sizeof(size_t)>::type
881  my_mask_reserved;
882 
884  /* my_mask always restored on restart. */
885  std::atomic<hashcode_type> my_mask;
886 
887  /* Size of value (key and value pair) stored in a pool */
888  std::size_t value_size;
889 
891  std::aligned_storage<24, 8>::type padding1;
892 
897  blocks_table_t my_table;
898 
899  /* It must be in separate cache line from my_mask due to performance
900  * effects */
902  std::atomic<size_type> my_size;
903 
905  std::aligned_storage<24, 8>::type padding2;
906 
908  persistent_ptr<tls_t> tls_ptr;
909 
915  p<size_t> on_init_size;
916 
918  std::aligned_storage<40, 8>::type reserved;
919 
921  segment_enable_mutex_t my_segment_enable_mutex;
922 
924  bucket my_embedded_segment[embedded_buckets];
925 
926  /* --------------------------------------------------------- */
927 
929  static constexpr features
930  header_features()
931  {
932  return {FEATURE_CONSISTENT_SIZE, 0};
933  }
934 
935  const std::atomic<hashcode_type> &
936  mask() const noexcept
937  {
938  return my_mask;
939  }
940 
941  std::atomic<hashcode_type> &
942  mask() noexcept
943  {
944  return my_mask;
945  }
946 
947  size_t
948  size() const
949  {
950  return my_size.load(std::memory_order_relaxed);
951  }
952 
953  p<int64_t> &
954  thread_size_diff()
955  {
956  assert(this->tls_ptr != nullptr);
957  return this->tls_ptr->local().size_diff;
958  }
959 
961  void
962  tls_restore()
963  {
964  assert(this->tls_ptr != nullptr);
965 
966  pool_base pop = pool_base{pmemobj_pool_by_ptr(this)};
967 
968  int64_t last_run_size = 0;
969  for (auto &data : *tls_ptr)
970  last_run_size += data.size_diff;
971 
972  /* Make sure that on_init_size + last_run_size >= 0 */
973  assert(last_run_size >= 0 ||
974  static_cast<int64_t>(static_cast<size_t>(last_run_size) +
975  on_init_size) >= 0);
976 
977  flat_transaction::run(pop, [&] {
978  on_init_size += static_cast<size_t>(last_run_size);
979  tls_ptr->clear();
980  });
981 
982  this->my_size = on_init_size;
983  }
984 
986  using const_segment_facade_t =
987  segment_facade_impl<blocks_table_t, segment_traits_t, true>;
988 
990  using segment_facade_t =
991  segment_facade_impl<blocks_table_t, segment_traits_t, false>;
992 
994  hash_map_base()
995  {
996  static_assert(
997  sizeof(size_type) == sizeof(std::atomic<size_type>),
998  "std::atomic should have the same layout as underlying integral type");
999 
1000 #if LIBPMEMOBJ_CPP_VG_HELGRIND_ENABLED
1001  VALGRIND_HG_DISABLE_CHECKING(&my_mask, sizeof(my_mask));
1002 #endif
1003  layout_features = {0, 0};
1004 
1005  PMEMoid oid = pmemobj_oid(this);
1006 
1007  assert(!OID_IS_NULL(oid));
1008 
1009  my_pool_uuid = oid.pool_uuid_lo;
1010 
1011  pool_base pop = get_pool_base();
1012  /* enable embedded segments */
1013  for (size_type i = 0; i < segment_traits_t::embedded_segments;
1014  ++i) {
1015  my_table[i] =
1016  pmemobj_oid(my_embedded_segment +
1017  segment_traits_t::segment_base(i));
1018  segment_facade_t seg(my_table, i);
1019  mark_rehashed<false>(pop, seg);
1020  }
1021 
1022  on_init_size = 0;
1023 
1024  value_size = 0;
1025 
1026  this->tls_ptr = nullptr;
1027  }
1028 
1029  /*
1030  * Should be called before concurrent_hash_map destructor is called.
1031  * Otherwise, program can terminate if an exception occurs while freeing
1032  * memory inside dtor.
1033  */
1034  void
1035  free_tls()
1036  {
1037  auto pop = get_pool_base();
1038 
1039  if ((layout_features.compat & FEATURE_CONSISTENT_SIZE) &&
1040  tls_ptr) {
1041  flat_transaction::run(pop, [&] {
1042  delete_persistent<tls_t>(tls_ptr);
1043  tls_ptr = nullptr;
1044  });
1045  }
1046  }
1047 
1051  void
1052  calculate_mask()
1053  {
1054 #if LIBPMEMOBJ_CPP_VG_HELGRIND_ENABLED
1055  VALGRIND_HG_DISABLE_CHECKING(&my_size, sizeof(my_size));
1056  VALGRIND_HG_DISABLE_CHECKING(&my_mask, sizeof(my_mask));
1057 #endif
1058 #if LIBPMEMOBJ_CPP_VG_PMEMCHECK_ENABLED
1059  VALGRIND_PMC_REMOVE_PMEM_MAPPING(&my_size, sizeof(my_size));
1060  VALGRIND_PMC_REMOVE_PMEM_MAPPING(&my_mask, sizeof(my_mask));
1061 #endif
1062 
1063  hashcode_type m = embedded_buckets - 1;
1064 
1065  const_segment_facade_t segment(
1066  my_table, segment_traits_t::embedded_segments);
1067 
1068  while (segment.is_valid()) {
1069  m += segment.size();
1070  ++segment;
1071  }
1072 
1073  mask().store(m, std::memory_order_relaxed);
1074  }
1075 
1079  template <bool Flush = true>
1080  void
1081  mark_rehashed(pool_base &pop, segment_facade_t &segment)
1082  {
1083  for (size_type i = 0; i < segment.size(); ++i) {
1084  bucket *b = &(segment[i]);
1085 
1086  assert_not_locked<mutex_t, scoped_t>(b->mutex);
1087 
1088  b->set_rehashed(std::memory_order_relaxed);
1089  }
1090 
1091  if (Flush) {
1092  /* Flush in separate loop to avoid read-after-flush */
1093  for (size_type i = 0; i < segment.size(); ++i) {
1094  bucket *b = &(segment[i]);
1095  pop.flush(b->rehashed);
1096  }
1097 
1098  pop.drain();
1099  }
1100  }
1101 
1105  void
1106  enable_segment(segment_index_t k, bool is_initial = false)
1107  {
1108  assert(k);
1109 
1110  pool_base pop = get_pool_base();
1111  size_type sz;
1112 
1113  if (k >= first_block) {
1114  segment_facade_t new_segment(my_table, k);
1115 
1116  sz = new_segment.size();
1117  if (!new_segment.is_valid())
1118  new_segment.enable(pop);
1119 
1120  if (is_initial) {
1121  mark_rehashed(pop, new_segment);
1122  }
1123 
1124  /* double it to get entire capacity of the container */
1125  sz <<= 1;
1126  } else {
1127  /* the first block */
1128  assert(k == segment_traits_t::embedded_segments);
1129 
1130  for (segment_index_t i = k; i < first_block; ++i) {
1131  segment_facade_t new_segment(my_table, i);
1132 
1133  if (!new_segment.is_valid())
1134  new_segment.enable(pop);
1135 
1136  if (is_initial) {
1137  mark_rehashed(pop, new_segment);
1138  }
1139  }
1140 
1141  sz = segment_traits_t::segment_size(first_block);
1142  }
1143 #if LIBPMEMOBJ_CPP_VG_HELGRIND_ENABLED
1144  ANNOTATE_HAPPENS_BEFORE(&my_mask);
1145 #endif
1146  mask().store(sz - 1, std::memory_order_release);
1147  }
1148 
1153  bucket *
1154  get_bucket(hashcode_type h) const
1155  {
1156  segment_index_t s = segment_traits_t::segment_index_of(h);
1157 
1158  h -= segment_traits_t::segment_base(s);
1159 
1160  const_segment_facade_t segment(my_table, s);
1161 
1162  assert(segment.is_valid());
1163 
1164  return &(segment[h]);
1165  }
1166 
1170  inline bool
1171  check_mask_race(hashcode_type h, hashcode_type &m) const
1172  {
1173  hashcode_type m_now, m_old = m;
1174 
1175  m_now = mask().load(std::memory_order_acquire);
1176 #if LIBPMEMOBJ_CPP_VG_HELGRIND_ENABLED
1177  ANNOTATE_HAPPENS_AFTER(&(this->my_mask));
1178 #endif
1179 
1180  if (m_old != m_now)
1181  return check_rehashing_collision(h, m_old, m = m_now);
1182 
1183  return false;
1184  }
1185 
1189  bool
1190  check_rehashing_collision(hashcode_type h, hashcode_type m_old,
1191  hashcode_type m) const
1192  {
1193  assert(m_old != m);
1194 
1195  if ((h & m_old) != (h & m)) {
1196  /* mask changed for this hashcode, rare event condition
1197  * above proves that 'h' has some other bits set beside
1198  * 'm_old', find next applicable mask after m_old */
1199 
1200  for (++m_old; !(h & m_old); m_old <<= 1)
1201  ;
1202 
1203  m_old = (m_old << 1) - 1; /* get full mask from a bit */
1204 
1205  assert((m_old & (m_old + 1)) == 0 && m_old <= m);
1206 
1207  /* check whether it is rehashing/ed */
1208  bucket *b = get_bucket(h & m_old);
1209  return b->is_rehashed(std::memory_order_acquire);
1210  }
1211 
1212  return false;
1213  }
1214 
1219  template <typename Node, typename... Args>
1220  void
1221  insert_new_node_internal(bucket *b,
1222  detail::persistent_pool_ptr<Node> &new_node,
1223  Args &&... args)
1224  {
1225  assert(pmemobj_tx_stage() == TX_STAGE_WORK);
1226 
1227  new_node = pmem::obj::make_persistent<Node>(
1228  b->node_list, std::forward<Args>(args)...);
1229  b->node_list = new_node; /* bucket is locked */
1230  }
1231 
1236  template <typename Node, typename... Args>
1237  size_type
1238  insert_new_node(bucket *b, detail::persistent_pool_ptr<Node> &new_node,
1239  Args &&... args)
1240  {
1241  pool_base pop = get_pool_base();
1242 
1243  /*
1244  * This is only true when called from singlethreaded methods
1245  * like swap() or operator=. In that case it's safe to directly
1246  * modify on_init_size.
1247  */
1248  if (pmemobj_tx_stage() == TX_STAGE_WORK) {
1249  insert_new_node_internal(b, new_node,
1250  std::forward<Args>(args)...);
1251  this->on_init_size++;
1252  } else {
1253  auto &size_diff = thread_size_diff();
1254 
1256  insert_new_node_internal(
1257  b, new_node,
1258  std::forward<Args>(args)...);
1259  ++size_diff;
1260  });
1261  }
1262 
1263  /* Increment volatile size */
1264  return ++(this->my_size);
1265  }
1266 
1271  bool
1272  check_growth(hashcode_type m, size_type sz)
1273  {
1274  if (sz >= m) {
1275  segment_index_t new_seg =
1276  static_cast<segment_index_t>(detail::Log2(
1277  m +
1278  1)); /* optimized segment_index_of */
1279 
1280  assert(segment_facade_t(my_table, new_seg - 1)
1281  .is_valid());
1282 
1283  std::unique_lock<segment_enable_mutex_t> lock(
1284  my_segment_enable_mutex, std::try_to_lock);
1285 
1286  if (lock) {
1287  if (mask().load(std::memory_order_relaxed) ==
1288  m) {
1289  /* Otherwise, other thread enable this
1290  * segment */
1291  enable_segment(new_seg);
1292 
1293  return true;
1294  }
1295  }
1296  }
1297 
1298  return false;
1299  }
1300 
1304  void
1305  reserve(size_type buckets)
1306  {
1307  if (buckets == 0)
1308  return;
1309 
1310  --buckets;
1311 
1312  bool is_initial = this->size() == 0;
1313 
1314  for (size_type m = mask(); buckets > m; m = mask())
1315  enable_segment(
1316  segment_traits_t::segment_index_of(m + 1),
1317  is_initial);
1318  }
1319 
1324  void
1325  internal_swap(hash_map_base<Key, T, mutex_t, scoped_t> &table)
1326  {
1327  pool_base p = get_pool_base();
1328  {
1330 
1331  this->my_pool_uuid.swap(table.my_pool_uuid);
1332 
1333  /*
1334  * As internal_swap can only be called
1335  * from one thread, and there can be an outer
1336  * transaction we must make sure that mask and size
1337  * changes are transactional
1338  */
1339  flat_transaction::snapshot((size_t *)&this->my_mask);
1340  flat_transaction::snapshot((size_t *)&this->my_size);
1341 
1342  this->mask() = table.mask().exchange(
1343  this->mask(), std::memory_order_relaxed);
1344 
1345  this->my_size = table.my_size.exchange(
1346  this->my_size, std::memory_order_relaxed);
1347 
1348  /* Swap consistent size */
1349  std::swap(this->tls_ptr, table.tls_ptr);
1350 
1351  for (size_type i = 0; i < embedded_buckets; ++i)
1352  this->my_embedded_segment[i].node_list.swap(
1353  table.my_embedded_segment[i].node_list);
1354 
1355  for (size_type i = segment_traits_t::embedded_segments;
1356  i < block_table_size; ++i)
1357  this->my_table[i].swap(table.my_table[i]);
1358 
1360  }
1361  }
1362 
1367  pool_base
1368  get_pool_base()
1369  {
1370  PMEMobjpool *pop =
1371  pmemobj_pool_by_oid(PMEMoid{my_pool_uuid, 0});
1372 
1373  return pool_base(pop);
1374  }
1375 }; /* End of class hash_map_base */
1376 
1382 template <typename Container, bool is_const>
1383 class hash_map_iterator {
1384 public:
1385  using iterator_category = std::forward_iterator_tag;
1386  using difference_type = ptrdiff_t;
1387  using map_type = Container;
1388  using value_type = typename map_type::value_type;
1389  using node = typename map_type::node;
1390  using bucket = typename map_type::bucket;
1391  using map_ptr = typename std::conditional<is_const, const map_type *,
1392  map_type *>::type;
1393  using reference =
1394  typename std::conditional<is_const,
1395  typename map_type::const_reference,
1396  typename map_type::reference>::type;
1397  using pointer =
1398  typename std::conditional<is_const,
1399  typename map_type::const_pointer,
1400  typename map_type::pointer>::type;
1401 
1402  template <typename C, bool M, bool U>
1403  friend bool operator==(const hash_map_iterator<C, M> &i,
1404  const hash_map_iterator<C, U> &j);
1405 
1406  template <typename C, bool M, bool U>
1407  friend bool operator!=(const hash_map_iterator<C, M> &i,
1408  const hash_map_iterator<C, U> &j);
1409 
1410  friend class hash_map_iterator<map_type, true>;
1411 
1412 #if !defined(_MSC_VER) || defined(__INTEL_COMPILER)
1413 private:
1414  template <typename Key, typename T, typename Hash, typename KeyEqual,
1415  typename MutexType, typename ScopedLockType>
1416  friend class ::pmem::obj::concurrent_hash_map;
1417 #else
1418 public: /* workaround */
1419 #endif
1420  hash_map_iterator(map_ptr map, size_t index)
1421  : my_map(map), my_index(index), my_bucket(nullptr), my_node(nullptr)
1422  {
1423  if (my_index <= my_map->mask()) {
1424  bucket_accessor acc(my_map, my_index);
1425  my_bucket = acc.get();
1426  my_node = static_cast<node *>(
1427  my_bucket->node_list.get(my_map->my_pool_uuid));
1428 
1429  if (!my_node) {
1430  advance_to_next_bucket();
1431  }
1432  }
1433  }
1434 
1435 public:
1437  hash_map_iterator() = default;
1438 
1440  hash_map_iterator(const hash_map_iterator &other)
1441  : my_map(other.my_map),
1442  my_index(other.my_index),
1443  my_bucket(other.my_bucket),
1444  my_node(other.my_node)
1445  {
1446  }
1447 
1449  template <typename U = void,
1450  typename = typename std::enable_if<is_const, U>::type>
1451  hash_map_iterator(const hash_map_iterator<map_type, false> &other)
1452  : my_map(other.my_map),
1453  my_index(other.my_index),
1454  my_bucket(other.my_bucket),
1455  my_node(other.my_node)
1456  {
1457  }
1458 
1459  hash_map_iterator &operator=(const hash_map_iterator &it) = default;
1460 
1462  reference operator*() const
1463  {
1464  assert(my_node);
1465  return my_node->item;
1466  }
1467 
1469  pointer operator->() const
1470  {
1471  return &operator*();
1472  }
1473 
1475  hash_map_iterator &
1476  operator++()
1477  {
1478  my_node = static_cast<node *>(
1479  my_node->next.get((my_map->my_pool_uuid)));
1480 
1481  if (!my_node)
1482  advance_to_next_bucket();
1483 
1484  return *this;
1485  }
1486 
1488  hash_map_iterator
1489  operator++(int)
1490  {
1491  hash_map_iterator old(*this);
1492  operator++();
1493  return old;
1494  }
1495 
1496 private:
1498  map_ptr my_map = nullptr;
1499 
1501  size_t my_index = 0;
1502 
1504  bucket *my_bucket = nullptr;
1505 
1507  node *my_node = nullptr;
1508 
1509  class bucket_accessor {
1510  public:
1511  bucket_accessor(map_ptr m, size_t index)
1512  {
1513  my_bucket = m->get_bucket(index);
1514  }
1515 
1516  bucket *
1517  get() const
1518  {
1519  return my_bucket;
1520  }
1521 
1522  private:
1523  bucket *my_bucket;
1524  };
1525 
1526  void
1527  advance_to_next_bucket()
1528  {
1529  size_t k = my_index + 1;
1530 
1531  assert(my_bucket);
1532 
1533  while (k <= my_map->mask()) {
1534  bucket_accessor acc(my_map, k);
1535  my_bucket = acc.get();
1536 
1537  if (my_bucket->node_list) {
1538  my_node = static_cast<node *>(
1539  my_bucket->node_list.get(
1540  my_map->my_pool_uuid));
1541 
1542  my_index = k;
1543 
1544  return;
1545  }
1546 
1547  ++k;
1548  }
1549 
1550  my_bucket = 0;
1551  my_node = 0;
1552  my_index = k;
1553  }
1554 };
1555 
1556 template <typename Container, bool M, bool U>
1557 bool
1558 operator==(const hash_map_iterator<Container, M> &i,
1559  const hash_map_iterator<Container, U> &j)
1560 {
1561  return i.my_node == j.my_node && i.my_map == j.my_map;
1562 }
1563 
1564 template <typename Container, bool M, bool U>
1565 bool
1566 operator!=(const hash_map_iterator<Container, M> &i,
1567  const hash_map_iterator<Container, U> &j)
1568 {
1569  return i.my_node != j.my_node || i.my_map != j.my_map;
1570 }
1571 } /* namespace concurrent_hash_map_internal */
1629 template <typename Key, typename T, typename Hash, typename KeyEqual,
1630  typename MutexType, typename ScopedLockType>
1632  : protected concurrent_hash_map_internal::hash_map_base<Key, T, MutexType,
1633  ScopedLockType> {
1634  template <typename Container, bool is_const>
1635  friend class concurrent_hash_map_internal::hash_map_iterator;
1636 
1637 public:
1638  using size_type = typename concurrent_hash_map_internal::hash_map_base<
1639  Key, T, MutexType, ScopedLockType>::size_type;
1640  using hashcode_type =
1641  typename concurrent_hash_map_internal::hash_map_base<
1642  Key, T, MutexType, ScopedLockType>::hashcode_type;
1643  using key_type = Key;
1644  using mapped_type = T;
1645  using value_type = typename concurrent_hash_map_internal::hash_map_base<
1646  Key, T, MutexType, ScopedLockType>::node::value_type;
1647  using difference_type = ptrdiff_t;
1648  using pointer = value_type *;
1649  using const_pointer = const value_type *;
1650  using reference = value_type &;
1651  using const_reference = const value_type &;
1652  using iterator = concurrent_hash_map_internal::hash_map_iterator<
1653  concurrent_hash_map, false>;
1654  using const_iterator = concurrent_hash_map_internal::hash_map_iterator<
1655  concurrent_hash_map, true>;
1656  using hasher = Hash;
1657  using key_equal = typename concurrent_hash_map_internal::key_equal_type<
1658  Hash, KeyEqual>::type;
1659 
1660 protected:
1661  using mutex_t = MutexType;
1662  using scoped_t = ScopedLockType;
1663  /*
1664  * Explicitly use methods and types from template base class
1665  */
1666  using hash_map_base =
1667  concurrent_hash_map_internal::hash_map_base<Key, T, mutex_t,
1668  scoped_t>;
1669  using hash_map_base::calculate_mask;
1670  using hash_map_base::check_growth;
1671  using hash_map_base::check_mask_race;
1672  using hash_map_base::embedded_buckets;
1673  using hash_map_base::FEATURE_CONSISTENT_SIZE;
1674  using hash_map_base::get_bucket;
1675  using hash_map_base::get_pool_base;
1676  using hash_map_base::header_features;
1677  using hash_map_base::insert_new_node;
1678  using hash_map_base::internal_swap;
1679  using hash_map_base::layout_features;
1680  using hash_map_base::mask;
1681  using hash_map_base::reserve;
1682  using tls_t = typename hash_map_base::tls_t;
1683  using node = typename hash_map_base::node;
1684  using node_mutex_t = typename node::mutex_t;
1685  using node_ptr_t = typename hash_map_base::node_ptr_t;
1686  using bucket = typename hash_map_base::bucket;
1687  using bucket_lock_type = typename bucket::scoped_t;
1688  using segment_index_t = typename hash_map_base::segment_index_t;
1689  using segment_traits_t = typename hash_map_base::segment_traits_t;
1690  using segment_facade_t = typename hash_map_base::segment_facade_t;
1691  using scoped_lock_traits_type =
1692  concurrent_hash_map_internal::scoped_lock_traits<scoped_t>;
1693 
1694  friend class const_accessor;
1695  using persistent_node_ptr_t = detail::persistent_pool_ptr<node>;
1696 
1697  void
1698  delete_node(const node_ptr_t &n)
1699  {
1700  delete_persistent<node>(
1701  detail::static_persistent_pool_pointer_cast<node>(n)
1702  .get_persistent_ptr(this->my_pool_uuid));
1703  }
1704 
1705  template <typename K>
1706  persistent_node_ptr_t
1707  search_bucket(const K &key, bucket *b) const
1708  {
1709  assert(b->is_rehashed(std::memory_order_relaxed));
1710 
1711  persistent_node_ptr_t n =
1712  detail::static_persistent_pool_pointer_cast<node>(
1713  b->node_list);
1714 
1715  while (n &&
1716  !key_equal{}(key,
1717  n.get(this->my_pool_uuid)->item.first)) {
1718  n = detail::static_persistent_pool_pointer_cast<node>(
1719  n.get(this->my_pool_uuid)->next);
1720  }
1721 
1722  return n;
1723  }
1724 
1729  class bucket_accessor : public bucket_lock_type {
1730  bucket *my_b;
1731 
1732  public:
1733  bucket_accessor(bucket_accessor &&b) noexcept : my_b(b.my_b)
1734  {
1735  bucket_lock_type::mutex = b.bucket_lock_type::mutex;
1736  bucket_lock_type::is_writer =
1737  b.bucket_lock_type::is_writer;
1738  b.my_b = nullptr;
1739  b.bucket_lock_type::mutex = nullptr;
1740  b.bucket_lock_type::is_writer = false;
1741  }
1742 
1744  const hashcode_type h, bool writer = false)
1745  {
1746  acquire(base, h, writer);
1747  }
1748 
1749  bucket_accessor(const bucket_accessor &other) = delete;
1750 
1751  bucket_accessor &
1752  operator=(const bucket_accessor &other) = delete;
1753 
1758  inline void
1759  acquire(concurrent_hash_map *base, const hashcode_type h,
1760  bool writer = false)
1761  {
1762  my_b = base->get_bucket(h);
1763 
1764  if (my_b->is_rehashed(std::memory_order_acquire) ==
1765  false &&
1766  bucket_lock_type::try_acquire(this->my_b->mutex,
1767  /*write=*/true)) {
1768  if (my_b->is_rehashed(
1769  std::memory_order_relaxed) ==
1770  false) {
1771  /* recursive rehashing */
1772  base->rehash_bucket<false>(my_b, h);
1773  }
1774  } else {
1775  bucket_lock_type::acquire(my_b->mutex, writer);
1776  }
1777 
1778  assert(my_b->is_rehashed(std::memory_order_relaxed));
1779  }
1780 
1784  bool
1785  is_writer() const
1786  {
1787  return bucket_lock_type::is_writer;
1788  }
1789 
1794  bucket *
1795  get() const
1796  {
1797  return my_b;
1798  }
1799 
1804  bucket *operator->() const
1805  {
1806  return this->get();
1807  }
1808  };
1809 
1814  bucket *my_b;
1815 
1816  public:
1818  const hashcode_type h,
1819  bool writer = false)
1820  {
1821  acquire(base, h, writer);
1822  }
1823 
1824  /*
1825  * Find a bucket by masked hashcode, optionally rehash
1826  */
1827  inline void
1828  acquire(concurrent_hash_map *base, const hashcode_type h,
1829  bool writer = false)
1830  {
1831  my_b = base->get_bucket(h);
1832 
1833  if (my_b->is_rehashed(std::memory_order_relaxed) ==
1834  false) {
1835  /* recursive rehashing */
1836  base->rehash_bucket<true>(my_b, h);
1837  }
1838 
1839  assert(my_b->is_rehashed(std::memory_order_relaxed));
1840  }
1841 
1848  bool
1849  is_writer() const
1850  {
1851  return true;
1852  }
1853 
1858  bucket *
1859  get() const
1860  {
1861  return my_b;
1862  }
1863 
1868  bucket *operator->() const
1869  {
1870  return this->get();
1871  }
1872  };
1873 
1874  hashcode_type
1875  get_hash_code(node_ptr_t &n)
1876  {
1877  return hasher{}(
1878  detail::static_persistent_pool_pointer_cast<node>(n)(
1879  this->my_pool_uuid)
1880  ->item.first);
1881  }
1882 
1883  template <bool serial>
1884  void
1885  rehash_bucket(bucket *b_new, const hashcode_type h)
1886  {
1887  using accessor_type = typename std::conditional<
1888  serial, serial_bucket_accessor, bucket_accessor>::type;
1889 
1890  using scoped_lock_traits_type =
1891  concurrent_hash_map_internal::scoped_lock_traits<
1892  accessor_type>;
1893 
1894  /* First two bucket should be always rehashed */
1895  assert(h > 1);
1896 
1897  pool_base pop = get_pool_base();
1898  node_ptr_t *p_new = &(b_new->node_list);
1899 
1900  /* This condition is only true when there was a failure just
1901  * before setting rehashed flag */
1902  if (*p_new != nullptr) {
1903  assert(!b_new->is_rehashed(std::memory_order_relaxed));
1904 
1905  b_new->set_rehashed(std::memory_order_relaxed);
1906  pop.persist(b_new->rehashed);
1907 
1908  return;
1909  }
1910 
1911  /* get parent mask from the topmost bit */
1912  hashcode_type mask = (1u << detail::Log2(h)) - 1;
1913  assert((h & mask) < h);
1914  accessor_type b_old(
1915  this, h & mask,
1916  scoped_lock_traits_type::initial_rw_state(true));
1917 
1919  /* get full mask for new bucket */
1920  mask = (mask << 1) | 1;
1921  assert((mask & (mask + 1)) == 0 && (h & mask) == h);
1922 
1923  restart:
1924  for (node_ptr_t *p_old = &(b_old->node_list),
1925  n = *p_old;
1926  n; n = *p_old) {
1927  hashcode_type c = get_hash_code(n);
1928 #ifndef NDEBUG
1929  hashcode_type bmask = h & (mask >> 1);
1930 
1931  bmask = bmask == 0
1932  ? 1 /* minimal mask of parent bucket */
1933  : (1u << (detail::Log2(bmask) + 1)) - 1;
1934 
1935  assert((c & bmask) == (h & bmask));
1936 #endif
1937 
1938  if ((c & mask) == h) {
1939  if (!b_old.is_writer() &&
1940  !scoped_lock_traits_type::
1941  upgrade_to_writer(b_old)) {
1942  goto restart;
1943  /* node ptr can be invalid due
1944  * to concurrent erase */
1945  }
1946 
1947  /* Add to new b_new */
1948  *p_new = n;
1949 
1950  /* exclude from b_old */
1951  *p_old = n(this->my_pool_uuid)->next;
1952 
1953  p_new = &(n(this->my_pool_uuid)->next);
1954  } else {
1955  /* iterate to next item */
1956  p_old = &(n(this->my_pool_uuid)->next);
1957  }
1958  }
1959 
1960  *p_new = nullptr;
1961  });
1962 
1963  /* mark rehashed */
1964  b_new->set_rehashed(std::memory_order_release);
1965  pop.persist(b_new->rehashed);
1966  }
1967 
1968  void
1969  check_incompat_features()
1970  {
1971  if (layout_features.incompat != header_features().incompat)
1972  throw pmem::layout_error(
1973  "Incompat flags mismatch, for more details go to: https://pmem.io/libpmemobj-cpp\n");
1974 
1975  if ((layout_features.compat & FEATURE_CONSISTENT_SIZE) &&
1976  this->value_size != sizeof(value_type))
1977  throw pmem::layout_error(
1978  "Size of value_type is different than the one stored in the pool\n");
1979  }
1980 
1981 public:
1982  class accessor;
1987  : protected node::scoped_t /*which derived from no_copy*/ {
1988  friend class concurrent_hash_map<Key, T, Hash, KeyEqual,
1989  mutex_t, scoped_t>;
1990  friend class accessor;
1992  using node::scoped_t::try_acquire;
1993 
1994  public:
1998  using value_type =
1999  const typename concurrent_hash_map::value_type;
2000 
2005  bool
2006  empty() const
2007  {
2008  return !my_node;
2009  }
2010 
2017  void
2019  {
2020  concurrent_hash_map_internal::check_outside_tx();
2021 
2022  if (my_node) {
2023  node::scoped_t::release();
2024  my_node = 0;
2025  }
2026  }
2027 
2031  const_reference operator*() const
2032  {
2033  assert(my_node);
2034 
2035  return my_node->item;
2036  }
2037 
2041  const_pointer operator->() const
2042  {
2043  return &operator*();
2044  }
2045 
2051  const_accessor() : my_node(OID_NULL), my_hash()
2052  {
2053  concurrent_hash_map_internal::check_outside_tx();
2054  }
2055 
2060  {
2061  my_node = OID_NULL; // scoped lock's release() is called
2062  // in its destructor
2063  }
2064 
2065  protected:
2066  node_ptr_t my_node;
2067 
2068  hashcode_type my_hash;
2069  };
2070 
2075  class accessor : public const_accessor {
2076  public:
2078  using value_type = typename concurrent_hash_map::value_type;
2079 
2081  reference operator*() const
2082  {
2083  assert(this->my_node);
2084 
2085  return this->my_node->item;
2086  }
2087 
2089  pointer operator->() const
2090  {
2091  return &operator*();
2092  }
2093  };
2094 
2098  concurrent_hash_map() : hash_map_base()
2099  {
2101  }
2102 
2107  concurrent_hash_map(size_type n) : hash_map_base()
2108  {
2110 
2111  reserve(n);
2112  }
2113 
2117  concurrent_hash_map(const concurrent_hash_map &table) : hash_map_base()
2118  {
2120 
2121  reserve(table.size());
2122 
2123  internal_copy(table);
2124  }
2125 
2129  concurrent_hash_map(concurrent_hash_map &&table) : hash_map_base()
2130  {
2132 
2133  swap(table);
2134  }
2135 
2139  template <typename I>
2140  concurrent_hash_map(I first, I last)
2141  {
2143 
2144  reserve(static_cast<size_type>(std::distance(first, last)));
2145 
2146  internal_copy(first, last);
2147  }
2148 
2152  concurrent_hash_map(std::initializer_list<value_type> il)
2153  {
2155 
2156  reserve(il.size());
2157 
2158  internal_copy(il.begin(), il.end());
2159  }
2160 
2169  void
2171  {
2172  check_incompat_features();
2173 
2174  calculate_mask();
2175 
2176  /*
2177  * Handle case where hash_map was created without
2178  * FEATURE_CONSISTENT_SIZE.
2179  */
2180  if (!(layout_features.compat & FEATURE_CONSISTENT_SIZE)) {
2181  auto actual_size =
2182  std::distance(this->begin(), this->end());
2183  assert(actual_size >= 0);
2184 
2185  this->my_size = static_cast<size_t>(actual_size);
2186 
2187  auto pop = get_pool_base();
2188  flat_transaction::run(pop, [&] {
2189  this->tls_ptr = make_persistent<tls_t>();
2190  this->on_init_size =
2191  static_cast<size_t>(actual_size);
2192  this->value_size = sizeof(value_type);
2193 
2194  layout_features.compat |=
2195  FEATURE_CONSISTENT_SIZE;
2196  });
2197  } else {
2198  assert(this->tls_ptr != nullptr);
2199  this->tls_restore();
2200  }
2201 
2202  assert(this->size() ==
2203  size_type(std::distance(this->begin(), this->end())));
2204  }
2205 
2206  [[deprecated(
2207  "runtime_initialize(bool) is now deprecated, use runtime_initialize(void)")]] void
2208  runtime_initialize(bool graceful_shutdown)
2209  {
2210  check_incompat_features();
2211 
2212  calculate_mask();
2213 
2214  if (!graceful_shutdown) {
2215  auto actual_size =
2216  std::distance(this->begin(), this->end());
2217  assert(actual_size >= 0);
2218  this->my_size = static_cast<size_type>(actual_size);
2219  } else {
2220  assert(this->size() ==
2221  size_type(std::distance(this->begin(),
2222  this->end())));
2223  }
2224  }
2225 
2237  concurrent_hash_map &
2239  {
2240  if (this != &table) {
2241  clear();
2242  internal_copy(table);
2243  }
2244 
2245  return *this;
2246  }
2247 
2260  operator=(std::initializer_list<value_type> il)
2261  {
2262  clear();
2263 
2264  reserve(il.size());
2265 
2266  internal_copy(il.begin(), il.end());
2267 
2268  return *this;
2269  }
2270 
2279  void rehash(size_type n = 0);
2280 
2287  void clear();
2288 
2306  void
2308  {
2309  if (!this->tls_ptr)
2310  return;
2311 
2312  auto pop = get_pool_base();
2313 
2314  flat_transaction::run(pop, [&] {
2315  clear();
2316  this->free_tls();
2317  });
2318  }
2319 
2329  {
2330  try {
2331  free_data();
2332  } catch (...) {
2333  std::terminate();
2334  }
2335  }
2336 
2337  //------------------------------------------------------------------------
2338  // STL support - not thread-safe methods
2339  //------------------------------------------------------------------------
2340 
2347  iterator
2349  {
2350  return iterator(this, 0);
2351  }
2352 
2357  iterator
2359  {
2360  return iterator(this, mask() + 1);
2361  }
2362 
2367  const_iterator
2368  begin() const
2369  {
2370  return const_iterator(this, 0);
2371  }
2372 
2377  const_iterator
2378  end() const
2379  {
2380  return const_iterator(this, mask() + 1);
2381  }
2382 
2386  size_type
2387  size() const
2388  {
2389  return hash_map_base::size();
2390  }
2391 
2395  bool
2396  empty() const
2397  {
2398  return this->size() == 0;
2399  }
2400 
2404  size_type
2405  max_size() const
2406  {
2407  return (~size_type(0)) / sizeof(node);
2408  }
2409 
2413  size_type
2415  {
2416  return mask() + 1;
2417  }
2418 
2422  void swap(concurrent_hash_map &table);
2423 
2424  //------------------------------------------------------------------------
2425  // concurrent map operations
2426  //------------------------------------------------------------------------
2427 
2433  size_type
2434  count(const Key &key) const
2435  {
2436  concurrent_hash_map_internal::check_outside_tx();
2437 
2438  return const_cast<concurrent_hash_map *>(this)->internal_find(
2439  key, nullptr, false);
2440  }
2441 
2453  template <typename K,
2454  typename = typename std::enable_if<
2455  concurrent_hash_map_internal::
2456  has_transparent_key_equal<hasher>::value,
2457  K>::type>
2458  size_type
2459  count(const K &key) const
2460  {
2461  concurrent_hash_map_internal::check_outside_tx();
2462 
2463  return const_cast<concurrent_hash_map *>(this)->internal_find(
2464  key, nullptr, false);
2465  }
2466 
2473  bool
2474  find(const_accessor &result, const Key &key) const
2475  {
2476  concurrent_hash_map_internal::check_outside_tx();
2477 
2478  result.release();
2479 
2480  return const_cast<concurrent_hash_map *>(this)->internal_find(
2481  key, &result, false);
2482  }
2483 
2497  template <typename K,
2498  typename = typename std::enable_if<
2499  concurrent_hash_map_internal::
2500  has_transparent_key_equal<hasher>::value,
2501  K>::type>
2502  bool
2503  find(const_accessor &result, const K &key) const
2504  {
2505  concurrent_hash_map_internal::check_outside_tx();
2506 
2507  result.release();
2508 
2509  return const_cast<concurrent_hash_map *>(this)->internal_find(
2510  key, &result, false);
2511  }
2512 
2519  bool
2520  find(accessor &result, const Key &key)
2521  {
2522  concurrent_hash_map_internal::check_outside_tx();
2523 
2524  result.release();
2525 
2526  return internal_find(key, &result, true);
2527  }
2528 
2542  template <typename K,
2543  typename = typename std::enable_if<
2544  concurrent_hash_map_internal::
2545  has_transparent_key_equal<hasher>::value,
2546  K>::type>
2547  bool
2548  find(accessor &result, const K &key)
2549  {
2550  concurrent_hash_map_internal::check_outside_tx();
2551 
2552  result.release();
2553 
2554  return internal_find(key, &result, true);
2555  }
2563  bool
2564  insert(const_accessor &result, const Key &key)
2565  {
2566  concurrent_hash_map_internal::check_outside_tx();
2567 
2568  result.release();
2569 
2570  return internal_insert(key, &result, false, key);
2571  }
2572 
2580  bool
2581  insert(accessor &result, const Key &key)
2582  {
2583  concurrent_hash_map_internal::check_outside_tx();
2584 
2585  result.release();
2586 
2587  return internal_insert(key, &result, true, key);
2588  }
2589 
2597  bool
2598  insert(const_accessor &result, const value_type &value)
2599  {
2600  concurrent_hash_map_internal::check_outside_tx();
2601 
2602  result.release();
2603 
2604  return internal_insert(value.first, &result, false, value);
2605  }
2606 
2614  bool
2615  insert(accessor &result, const value_type &value)
2616  {
2617  concurrent_hash_map_internal::check_outside_tx();
2618 
2619  result.release();
2620 
2621  return internal_insert(value.first, &result, true, value);
2622  }
2623 
2630  bool
2631  insert(const value_type &value)
2632  {
2633  concurrent_hash_map_internal::check_outside_tx();
2634 
2635  return internal_insert(value.first, nullptr, false, value);
2636  }
2637 
2645  bool
2646  insert(const_accessor &result, value_type &&value)
2647  {
2648  concurrent_hash_map_internal::check_outside_tx();
2649 
2650  result.release();
2651 
2652  return internal_insert(value.first, &result, false,
2653  std::move(value));
2654  }
2655 
2663  bool
2664  insert(accessor &result, value_type &&value)
2665  {
2666  concurrent_hash_map_internal::check_outside_tx();
2667 
2668  result.release();
2669 
2670  return internal_insert(value.first, &result, true,
2671  std::move(value));
2672  }
2673 
2680  bool
2681  insert(value_type &&value)
2682  {
2683  concurrent_hash_map_internal::check_outside_tx();
2684 
2685  return internal_insert(value.first, nullptr, false,
2686  std::move(value));
2687  }
2688 
2694  template <typename I>
2695  void
2696  insert(I first, I last)
2697  {
2698  concurrent_hash_map_internal::check_outside_tx();
2699 
2700  for (; first != last; ++first)
2701  insert(*first);
2702  }
2703 
2709  void
2710  insert(std::initializer_list<value_type> il)
2711  {
2712  concurrent_hash_map_internal::check_outside_tx();
2713 
2714  insert(il.begin(), il.end());
2715  }
2716 
2725  template <typename M>
2726  bool
2727  insert_or_assign(const key_type &key, M &&obj)
2728  {
2729  concurrent_hash_map_internal::check_outside_tx();
2730 
2731  accessor acc;
2732  auto result = internal_insert(key, &acc, true, key,
2733  std::forward<M>(obj));
2734 
2735  if (!result) {
2736  pool_base pop = get_pool_base();
2738  acc->second = std::forward<M>(obj);
2740  }
2741 
2742  return result;
2743  }
2744 
2753  template <typename M>
2754  bool
2755  insert_or_assign(key_type &&key, M &&obj)
2756  {
2757  concurrent_hash_map_internal::check_outside_tx();
2758 
2759  accessor acc;
2760  auto result = internal_insert(key, &acc, true, std::move(key),
2761  std::forward<M>(obj));
2762 
2763  if (!result) {
2764  pool_base pop = get_pool_base();
2766  acc->second = std::forward<M>(obj);
2768  }
2769 
2770  return result;
2771  }
2772 
2781  template <
2782  typename K, typename M,
2783  typename = typename std::enable_if<
2784  concurrent_hash_map_internal::has_transparent_key_equal<
2785  hasher>::value &&
2786  std::is_constructible<key_type, K>::value,
2787  K>::type>
2788  bool
2789  insert_or_assign(K &&key, M &&obj)
2790  {
2791  concurrent_hash_map_internal::check_outside_tx();
2792 
2793  accessor acc;
2794  auto result =
2795  internal_insert(key, &acc, true, std::forward<K>(key),
2796  std::forward<M>(obj));
2797 
2798  if (!result) {
2799  pool_base pop = get_pool_base();
2801  acc->second = std::forward<M>(obj);
2803  }
2804 
2805  return result;
2806  }
2807 
2816  bool
2817  erase(const Key &key)
2818  {
2819  concurrent_hash_map_internal::check_outside_tx();
2820 
2821  return internal_erase(key);
2822  }
2823 
2842  pobj_defrag_result
2843  defragment(double start_percent = 0, double amount_percent = 100)
2844  {
2845  double end_percent = start_percent + amount_percent;
2846  if (start_percent < 0 || start_percent >= 100 ||
2847  end_percent < 0 || end_percent > 100 ||
2848  start_percent >= end_percent) {
2849  throw std::range_error("incorrect range");
2850  }
2851 
2852  size_t max_index = mask().load(std::memory_order_acquire);
2853  size_t start_index =
2854  static_cast<size_t>((start_percent * max_index) / 100);
2855  size_t end_index =
2856  static_cast<size_t>((end_percent * max_index) / 100);
2857 
2858  /* Make sure we do not use too big index, even in case of
2859  * rounding errors. */
2860  end_index = (std::min)(end_index, max_index);
2861 
2862 #if LIBPMEMOBJ_CPP_VG_HELGRIND_ENABLED
2863  ANNOTATE_HAPPENS_AFTER(&(this->my_mask));
2864 #endif
2865 
2866  /* Create defrag object for elements in the current pool */
2867  pmem::obj::defrag my_defrag(this->get_pool_base());
2868  mutex_vector mv;
2869 
2870  /*
2871  * Locks are taken in the backward order to avoid deadlocks
2872  * with the rehashing of buckets.
2873  *
2874  * We do '+ 1' and '- 1' to handle the 'i == 0' case.
2875  */
2876  for (size_t i = end_index + 1; i >= start_index + 1; i--) {
2877  /*
2878  * All locks will be unlocked automatically
2879  * in the destructor of 'mv'.
2880  */
2881  bucket *b = mv.push_and_try_lock(this, i - 1);
2882  if (b == nullptr)
2883  continue;
2884 
2885  defrag_save_nodes(b, my_defrag);
2886  }
2887 
2888  return my_defrag.run();
2889  }
2890 
2905  template <typename K,
2906  typename = typename std::enable_if<
2907  concurrent_hash_map_internal::
2908  has_transparent_key_equal<hasher>::value,
2909  K>::type>
2910  bool
2911  erase(const K &key)
2912  {
2913  concurrent_hash_map_internal::check_outside_tx();
2914 
2915  return internal_erase(key);
2916  }
2917 
2918 protected:
2919  /*
2920  * Try to acquire the mutex for read or write.
2921  *
2922  * If acquiring succeeds returns true, otherwise retries for few times.
2923  * If acquiring fails after all attempts returns false.
2924  */
2925  bool try_acquire_item(const_accessor *result, node_mutex_t &mutex,
2926  bool write);
2927 
2933  public:
2934  using mutex_t = MutexType;
2935 
2937  bucket *
2938  push_and_try_lock(concurrent_hash_map *base, hashcode_type h)
2939  {
2940  vec.emplace_back(base, h, true /*writer*/);
2941  bucket *b = vec.back().get();
2942 
2943  auto node_ptr = static_cast<node *>(
2944  b->node_list.get(base->my_pool_uuid));
2945 
2946  while (node_ptr) {
2947  const_accessor ca;
2948  if (!base->try_acquire_item(&ca,
2949  node_ptr->mutex,
2950  /*write=*/true)) {
2951  vec.pop_back();
2952  return nullptr;
2953  }
2954 
2955  node_ptr =
2956  static_cast<node *>(node_ptr->next.get(
2957  (base->my_pool_uuid)));
2958  }
2959 
2960  return b;
2961  }
2962 
2963  private:
2964  std::vector<bucket_accessor> vec;
2965  };
2966 
2967  template <typename K>
2968  bool internal_find(const K &key, const_accessor *result, bool write);
2969 
2970  template <typename K, typename... Args>
2971  bool internal_insert(const K &key, const_accessor *result, bool write,
2972  Args &&... args);
2973 
2974  /* Obtain pointer to node and lock bucket */
2975  template <bool Bucket_rw_lock, typename K>
2976  persistent_node_ptr_t
2977  get_node(const K &key, bucket_accessor &b)
2978  {
2979  /* find a node */
2980  auto n = search_bucket(key, b.get());
2981 
2982  if (!n) {
2983  if (Bucket_rw_lock && !b.is_writer() &&
2984  !scoped_lock_traits_type::upgrade_to_writer(b)) {
2985  /* Rerun search_list, in case another
2986  * thread inserted the item during the
2987  * upgrade. */
2988  n = search_bucket(key, b.get());
2989  if (n) {
2990  /* unfortunately, it did */
2991  scoped_lock_traits_type::
2992  downgrade_to_reader(b);
2993  return n;
2994  }
2995  }
2996  }
2997 
2998  return n;
2999  }
3000 
3001  template <typename K>
3002  bool internal_erase(const K &key);
3003 
3004  void clear_segment(segment_index_t s);
3005 
3009  void internal_copy(const concurrent_hash_map &source);
3010 
3011  template <typename I>
3012  void internal_copy(I first, I last);
3013 
3018  void
3020  {
3021  auto node_ptr = static_cast<node *>(
3022  b->node_list.get(this->my_pool_uuid));
3023 
3024  while (node_ptr) {
3025  /*
3026  * We do not perform the defragmentation
3027  * on node pointers, because nodes
3028  * always have the same size.
3029  */
3030  defrag.add(node_ptr->item.first);
3031  defrag.add(node_ptr->item.second);
3032 
3033  node_ptr = static_cast<node *>(
3034  node_ptr->next.get((this->my_pool_uuid)));
3035  }
3036  }
3037 }; // class concurrent_hash_map
3038 
3039 template <typename Key, typename T, typename Hash, typename KeyEqual,
3040  typename MutexType, typename ScopedLockType>
3041 bool
3042 concurrent_hash_map<Key, T, Hash, KeyEqual, MutexType,
3043  ScopedLockType>::try_acquire_item(const_accessor *result,
3044  node_mutex_t &mutex,
3045  bool write)
3046 {
3047  /* acquire the item */
3048  if (!result->try_acquire(mutex, write)) {
3049  for (detail::atomic_backoff backoff(true);;) {
3050  if (result->try_acquire(mutex, write))
3051  break;
3052 
3053  if (!backoff.bounded_pause())
3054  return false;
3055  }
3056  }
3057 
3058  return true;
3059 }
3060 
3061 template <typename Key, typename T, typename Hash, typename KeyEqual,
3062  typename MutexType, typename ScopedLockType>
3063 template <typename K>
3064 bool
3065 concurrent_hash_map<Key, T, Hash, KeyEqual, MutexType,
3066  ScopedLockType>::internal_find(const K &key,
3067  const_accessor *result,
3068  bool write)
3069 {
3070  assert(!result || !result->my_node);
3071 
3072  hashcode_type m = mask().load(std::memory_order_acquire);
3073 #if LIBPMEMOBJ_CPP_VG_HELGRIND_ENABLED
3074  ANNOTATE_HAPPENS_AFTER(&(this->my_mask));
3075 #endif
3076 
3077  assert((m & (m + 1)) == 0);
3078 
3079  hashcode_type const h = hasher{}(key);
3080 
3081  persistent_node_ptr_t node;
3082 
3083  while (true) {
3084  /* get bucket and acquire the lock */
3085  bucket_accessor b(
3086  this, h & m,
3087  scoped_lock_traits_type::initial_rw_state(false));
3088  node = get_node<false>(key, b);
3089 
3090  if (!node) {
3091  /* Element was possibly relocated, try again */
3092  if (check_mask_race(h, m)) {
3093  b.release();
3094  continue;
3095  } else {
3096  return false;
3097  }
3098  }
3099 
3100  /* No need to acquire the item or item acquired */
3101  if (!result ||
3102  try_acquire_item(
3103  result, node.get(this->my_pool_uuid)->mutex, write))
3104  break;
3105 
3106  /* the wait takes really long, restart the
3107  * operation */
3108  b.release();
3109 
3110  std::this_thread::yield();
3111 
3112  m = mask().load(std::memory_order_acquire);
3113 #if LIBPMEMOBJ_CPP_VG_HELGRIND_ENABLED
3114  ANNOTATE_HAPPENS_AFTER(&(this->my_mask));
3115 #endif
3116  }
3117 
3118  if (result) {
3119  result->my_node = node.get_persistent_ptr(this->my_pool_uuid);
3120  result->my_hash = h;
3121  }
3122 
3123  return true;
3124 }
3125 
3126 template <typename Key, typename T, typename Hash, typename KeyEqual,
3127  typename MutexType, typename ScopedLockType>
3128 template <typename K, typename... Args>
3129 bool
3130 concurrent_hash_map<Key, T, Hash, KeyEqual, MutexType,
3131  ScopedLockType>::internal_insert(const K &key,
3132  const_accessor *result,
3133  bool write,
3134  Args &&... args)
3135 {
3136  assert(!result || !result->my_node);
3137 
3138  hashcode_type m = mask().load(std::memory_order_acquire);
3139 #if LIBPMEMOBJ_CPP_VG_HELGRIND_ENABLED
3140  ANNOTATE_HAPPENS_AFTER(&(this->my_mask));
3141 #endif
3142 
3143  assert((m & (m + 1)) == 0);
3144 
3145  hashcode_type const h = hasher{}(key);
3146 
3147  persistent_node_ptr_t node;
3148  size_t new_size = 0;
3149  bool inserted = false;
3150 
3151  while (true) {
3152  /* get bucket and acquire the lock */
3153  bucket_accessor b(
3154  this, h & m,
3155  scoped_lock_traits_type::initial_rw_state(true));
3156  node = get_node<true>(key, b);
3157 
3158  if (!node) {
3159  /* Element was possibly relocated, try again */
3160  if (check_mask_race(h, m)) {
3161  b.release();
3162  continue;
3163  }
3164 
3165  /* insert and set flag to grow the container */
3166  new_size = insert_new_node(b.get(), node,
3167  std::forward<Args>(args)...);
3168  inserted = true;
3169  }
3170 
3171  /* No need to acquire the item or item acquired */
3172  if (!result ||
3173  try_acquire_item(
3174  result, node.get(this->my_pool_uuid)->mutex, write))
3175  break;
3176 
3177  /* the wait takes really long, restart the
3178  * operation */
3179  b.release();
3180 
3181  std::this_thread::yield();
3182 
3183  m = mask().load(std::memory_order_acquire);
3184 #if LIBPMEMOBJ_CPP_VG_HELGRIND_ENABLED
3185  ANNOTATE_HAPPENS_AFTER(&(this->my_mask));
3186 #endif
3187  }
3188 
3189  if (result) {
3190  result->my_node = node.get_persistent_ptr(this->my_pool_uuid);
3191  result->my_hash = h;
3192  }
3193 
3194  check_growth(m, new_size);
3195 
3196  return inserted;
3197 }
3198 
3199 template <typename Key, typename T, typename Hash, typename KeyEqual,
3200  typename MutexType, typename ScopedLockType>
3201 template <typename K>
3202 bool
3203 concurrent_hash_map<Key, T, Hash, KeyEqual, MutexType,
3204  ScopedLockType>::internal_erase(const K &key)
3205 {
3206  node_ptr_t n;
3207  hashcode_type const h = hasher{}(key);
3208  hashcode_type m = mask().load(std::memory_order_acquire);
3209 #if LIBPMEMOBJ_CPP_VG_HELGRIND_ENABLED
3210  ANNOTATE_HAPPENS_AFTER(&(this->my_mask));
3211 #endif
3212 
3213  pool_base pop = get_pool_base();
3214 
3215 restart : {
3216  /* lock scope */
3217  /* get bucket */
3218  bucket_accessor b(this, h & m,
3219  scoped_lock_traits_type::initial_rw_state(true));
3220 
3221 search:
3222  node_ptr_t *p = &b->node_list;
3223  n = *p;
3224 
3225  while (n &&
3226  !key_equal{}(key,
3227  detail::static_persistent_pool_pointer_cast<node>(
3228  n)(this->my_pool_uuid)
3229  ->item.first)) {
3230  p = &n(this->my_pool_uuid)->next;
3231  n = *p;
3232  }
3233 
3234  if (!n) {
3235  /* not found, but mask could be changed */
3236  if (check_mask_race(h, m))
3237  goto restart;
3238 
3239  return false;
3240  } else if (!b.is_writer() &&
3241  !scoped_lock_traits_type::upgrade_to_writer(b)) {
3242  if (check_mask_race(h, m)) /* contended upgrade, check mask */
3243  goto restart;
3244 
3245  goto search;
3246  }
3247 
3248  persistent_ptr<node> del = n(this->my_pool_uuid);
3249 
3250  {
3251  /* We cannot remove this element immediately because
3252  * other threads might work with this element via
3253  * accessors. The item_locker required to wait while
3254  * other threads use the node. */
3255  const_accessor acc;
3256  if (!try_acquire_item(&acc, del->mutex, true)) {
3257  /* the wait takes really long, restart the operation */
3258  b.release();
3259 
3260  std::this_thread::yield();
3261 
3262  m = mask().load(std::memory_order_acquire);
3263 
3264  goto restart;
3265  }
3266  }
3267 
3268  assert(pmemobj_tx_stage() == TX_STAGE_NONE);
3269 
3270  auto &size_diff = this->thread_size_diff();
3271 
3272  /* Only one thread can delete it due to write lock on the bucket
3273  */
3274  flat_transaction::run(pop, [&] {
3275  *p = del->next;
3276  delete_node(del);
3277 
3278  --size_diff;
3279  });
3280 
3281  --(this->my_size);
3282 }
3283 
3284  return true;
3285 }
3286 
3287 template <typename Key, typename T, typename Hash, typename KeyEqual,
3288  typename MutexType, typename ScopedLockType>
3289 void
3292 {
3293  internal_swap(table);
3294 }
3295 
3296 template <typename Key, typename T, typename Hash, typename KeyEqual,
3297  typename MutexType, typename ScopedLockType>
3298 void
3300  size_type sz)
3301 {
3302  concurrent_hash_map_internal::check_outside_tx();
3303 
3304  reserve(sz);
3305  hashcode_type m = mask();
3306 
3307  /* only the last segment should be scanned for rehashing size or first
3308  * index of the last segment */
3309  hashcode_type b = (m + 1) >> 1;
3310 
3311  /* zero or power of 2 */
3312  assert((b & (b - 1)) == 0);
3313 
3314  for (; b <= m; ++b) {
3315  bucket *bp = get_bucket(b);
3316 
3317  concurrent_hash_map_internal::assert_not_locked<mutex_t,
3318  scoped_t>(
3319  bp->mutex);
3320  /* XXX Need to investigate if this statement is needed */
3321  if (bp->is_rehashed(std::memory_order_relaxed) == false)
3322  rehash_bucket<true>(bp, b);
3323  }
3324 }
3325 
3326 template <typename Key, typename T, typename Hash, typename KeyEqual,
3327  typename MutexType, typename ScopedLockType>
3328 void
3330 {
3331  hashcode_type m = mask();
3332 
3333  assert((m & (m + 1)) == 0);
3334 
3335 #ifndef NDEBUG
3336  /* check consistency */
3337  for (segment_index_t b = 0; b <= m; ++b) {
3338  bucket *bp = get_bucket(b);
3339  concurrent_hash_map_internal::assert_not_locked<mutex_t,
3340  scoped_t>(
3341  bp->mutex);
3342  }
3343 #endif
3344 
3345  pool_base pop = get_pool_base();
3346  { /* transaction scope */
3347 
3348  flat_transaction::manual tx(pop);
3349 
3350  assert(this->tls_ptr != nullptr);
3351  this->tls_ptr->clear();
3352 
3353  this->on_init_size = 0;
3354 
3355  segment_index_t s = segment_traits_t::segment_index_of(m);
3356 
3357  assert(s + 1 == this->block_table_size ||
3358  !segment_facade_t(this->my_table, s + 1).is_valid());
3359 
3360  do {
3361  clear_segment(s);
3362  } while (s-- > 0);
3363 
3364  /*
3365  * As clear can only be called
3366  * from one thread, and there can be an outer
3367  * transaction we must make sure that mask and size
3368  * changes are transactional
3369  */
3370  flat_transaction::snapshot((size_t *)&this->my_mask);
3371  flat_transaction::snapshot((size_t *)&this->my_size);
3372 
3373  mask().store(embedded_buckets - 1, std::memory_order_relaxed);
3374  this->my_size = 0;
3375 
3377  }
3378 }
3379 
3380 template <typename Key, typename T, typename Hash, typename KeyEqual,
3381  typename MutexType, typename ScopedLockType>
3382 void
3383 concurrent_hash_map<Key, T, Hash, KeyEqual, MutexType,
3384  ScopedLockType>::clear_segment(segment_index_t s)
3385 {
3386  segment_facade_t segment(this->my_table, s);
3387 
3388  assert(segment.is_valid());
3389 
3390  size_type sz = segment.size();
3391  for (segment_index_t i = 0; i < sz; ++i) {
3392  for (node_ptr_t n = segment[i].node_list; n;
3393  n = segment[i].node_list) {
3394  segment[i].node_list = n(this->my_pool_uuid)->next;
3395  delete_node(n);
3396  }
3397  }
3398 
3399  if (s >= segment_traits_t::embedded_segments)
3400  segment.disable();
3401 }
3402 
3403 template <typename Key, typename T, typename Hash, typename KeyEqual,
3404  typename MutexType, typename ScopedLockType>
3405 void
3407  internal_copy(const concurrent_hash_map &source)
3408 {
3409  auto pop = get_pool_base();
3410 
3411  reserve(source.size());
3412  internal_copy(source.begin(), source.end());
3413 }
3414 
3415 template <typename Key, typename T, typename Hash, typename KeyEqual,
3416  typename MutexType, typename ScopedLockType>
3417 template <typename I>
3418 void
3419 concurrent_hash_map<Key, T, Hash, KeyEqual, MutexType,
3420  ScopedLockType>::internal_copy(I first, I last)
3421 {
3422  hashcode_type m = mask();
3423 
3424  for (; first != last; ++first) {
3425  hashcode_type h = hasher{}(first->first);
3426  bucket *b = get_bucket(h & m);
3427 
3428  assert(b->is_rehashed(std::memory_order_relaxed));
3429 
3430  detail::persistent_pool_ptr<node> p;
3431  insert_new_node(b, p, *first);
3432  }
3433 }
3434 
3435 template <typename Key, typename T, typename Hash, typename KeyEqual,
3436  typename MutexType, typename ScopedLockType>
3437 inline bool
3438 operator==(const concurrent_hash_map<Key, T, Hash, KeyEqual, MutexType,
3439  ScopedLockType> &a,
3440  const concurrent_hash_map<Key, T, Hash, KeyEqual, MutexType,
3441  ScopedLockType> &b)
3442 {
3443  if (a.size() != b.size())
3444  return false;
3445 
3446  typename concurrent_hash_map<Key, T, Hash, KeyEqual, MutexType,
3447  ScopedLockType>::const_iterator
3448  i(a.begin()),
3449  i_end(a.end());
3450 
3451  typename concurrent_hash_map<Key, T, Hash, KeyEqual, MutexType,
3452  ScopedLockType>::const_iterator j,
3453  j_end(b.end());
3454 
3455  for (; i != i_end; ++i) {
3456  j = b.equal_range(i->first).first;
3457 
3458  if (j == j_end || !(i->second == j->second))
3459  return false;
3460  }
3461 
3462  return true;
3463 }
3464 
3465 template <typename Key, typename T, typename Hash, typename KeyEqual,
3466  typename MutexType, typename ScopedLockType>
3467 inline bool
3468 operator!=(const concurrent_hash_map<Key, T, Hash, KeyEqual, MutexType,
3469  ScopedLockType> &a,
3470  const concurrent_hash_map<Key, T, Hash, KeyEqual, MutexType,
3471  ScopedLockType> &b)
3472 {
3473  return !(a == b);
3474 }
3475 
3476 template <typename Key, typename T, typename Hash, typename KeyEqual,
3477  typename MutexType, typename ScopedLockType>
3478 inline void
3479 swap(concurrent_hash_map<Key, T, Hash, KeyEqual, MutexType, ScopedLockType> &a,
3480  concurrent_hash_map<Key, T, Hash, KeyEqual, MutexType, ScopedLockType> &b)
3481 {
3482  a.swap(b);
3483 }
3484 
3485 } /* namespace obj */
3486 } /* namespace pmem */
3487 
3488 #endif /* PMEMOBJ_CONCURRENT_HASH_MAP_HPP */
Atomic backoff, for time delay.
static void commit()
Manually commit a transaction.
Definition: transaction.hpp:330
static void snapshot(const T *addr, size_t num=1)
Takes a “snapshot” of given elements of type T number (1 by default), located at the given address pt...
Definition: transaction.hpp:437
Custom layout error class.
Definition: pexceptions.hpp:189
Allows write access to elements and combines data access, locking, and garbage collection.
Definition: concurrent_hash_map.hpp:2075
pointer operator->() const
Return pointer to associated value in hash table.
Definition: concurrent_hash_map.hpp:2089
reference operator*() const
Return reference to associated value in hash table.
Definition: concurrent_hash_map.hpp:2081
Bucket accessor is to find, rehash, acquire a lock, and access a bucket.
Definition: concurrent_hash_map.hpp:1729
void acquire(concurrent_hash_map *base, const hashcode_type h, bool writer=false)
Find a bucket by masked hashcode, optionally rehash, and acquire the lock.
Definition: concurrent_hash_map.hpp:1759
bool is_writer() const
Check whether bucket is locked for write.
Definition: concurrent_hash_map.hpp:1785
bucket * operator->() const
Overloaded arrow operator.
Definition: concurrent_hash_map.hpp:1804
bucket * get() const
Get bucket pointer.
Definition: concurrent_hash_map.hpp:1795
Combines data access, locking, and garbage collection.
Definition: concurrent_hash_map.hpp:1987
bool empty() const
Definition: concurrent_hash_map.hpp:2006
const_accessor()
Create empty result.
Definition: concurrent_hash_map.hpp:2051
void release()
Release accessor.
Definition: concurrent_hash_map.hpp:2018
const typename concurrent_hash_map::value_type value_type
Type of value.
Definition: concurrent_hash_map.hpp:1999
~const_accessor()
Destroy result after releasing the underlying reference.
Definition: concurrent_hash_map.hpp:2059
const_reference operator*() const
Definition: concurrent_hash_map.hpp:2031
const_pointer operator->() const
Definition: concurrent_hash_map.hpp:2041
Vector of locks to be unlocked at the destruction time.
Definition: concurrent_hash_map.hpp:2932
bucket * push_and_try_lock(concurrent_hash_map *base, hashcode_type h)
Save pointer to the lock in the vector and lock it.
Definition: concurrent_hash_map.hpp:2938
Serial bucket accessor used to access bucket in a serial operations.
Definition: concurrent_hash_map.hpp:1813
bucket * operator->() const
Overloaded arrow operator.
Definition: concurrent_hash_map.hpp:1868
bool is_writer() const
This method is added for consistency with bucket_accessor class.
Definition: concurrent_hash_map.hpp:1849
bucket * get() const
Get bucket pointer.
Definition: concurrent_hash_map.hpp:1859
Persistent memory aware implementation of Intel TBB concurrent_hash_map
Definition: concurrent_hash_map.hpp:1633
bool empty() const
Definition: concurrent_hash_map.hpp:2396
const_iterator end() const
Definition: concurrent_hash_map.hpp:2378
iterator end()
Definition: concurrent_hash_map.hpp:2358
size_type bucket_count() const
Definition: concurrent_hash_map.hpp:2414
void insert(std::initializer_list< value_type > il)
Insert initializer list.
Definition: concurrent_hash_map.hpp:2710
bool find(accessor &result, const Key &key)
Find item and acquire a write lock on the item.
Definition: concurrent_hash_map.hpp:2520
bool insert(accessor &result, value_type &&value)
Insert item by copying if there is no such key present already and acquire a write lock on the item.
Definition: concurrent_hash_map.hpp:2664
concurrent_hash_map & operator=(const concurrent_hash_map &table)
Assignment Not thread safe.
Definition: concurrent_hash_map.hpp:2238
bool find(const_accessor &result, const Key &key) const
Find item and acquire a read lock on the item.
Definition: concurrent_hash_map.hpp:2474
size_type count(const Key &key) const
Definition: concurrent_hash_map.hpp:2434
const_iterator begin() const
Definition: concurrent_hash_map.hpp:2368
size_type size() const
Definition: concurrent_hash_map.hpp:2387
bool insert(const_accessor &result, value_type &&value)
Insert item by copying if there is no such key present already and acquire a read lock on the item.
Definition: concurrent_hash_map.hpp:2646
bool insert(const value_type &value)
Insert item by copying if there is no such key present already.
Definition: concurrent_hash_map.hpp:2631
~concurrent_hash_map()
free_data should be called before concurrent_hash_map destructor is called.
Definition: concurrent_hash_map.hpp:2328
void clear()
Clear hash map content Not thread safe.
Definition: concurrent_hash_map.hpp:3329
void free_data()
Destroys the concurrent_hash_map.
Definition: concurrent_hash_map.hpp:2307
void swap(concurrent_hash_map &table)
Swap two instances.
Definition: concurrent_hash_map.hpp:3290
iterator begin()
Definition: concurrent_hash_map.hpp:2348
void rehash(size_type n=0)
Rehashes and optionally resizes the whole table.
Definition: concurrent_hash_map.hpp:3299
bool insert_or_assign(K &&key, M &&obj)
Inserts item if there is no such key-comparable type present already, assigns provided value otherwis...
Definition: concurrent_hash_map.hpp:2789
void defrag_save_nodes(bucket *b, pmem::obj::defrag &defrag)
Internal method used by defragment().
Definition: concurrent_hash_map.hpp:3019
size_type count(const K &key) const
This overload only participates in overload resolution if the qualified-id Hash::transparent_key_equa...
Definition: concurrent_hash_map.hpp:2459
bool find(accessor &result, const K &key)
Find item and acquire a write lock on the item.
Definition: concurrent_hash_map.hpp:2548
bool insert(const_accessor &result, const value_type &value)
Insert item by copying if there is no such key present already and acquire a read lock on the item.
Definition: concurrent_hash_map.hpp:2598
bool insert(accessor &result, const value_type &value)
Insert item by copying if there is no such key present already and acquire a write lock on the item.
Definition: concurrent_hash_map.hpp:2615
bool erase(const Key &key)
Remove element with corresponding key.
Definition: concurrent_hash_map.hpp:2817
bool insert(value_type &&value)
Insert item by copying if there is no such key present already.
Definition: concurrent_hash_map.hpp:2681
concurrent_hash_map()
Construct empty table.
Definition: concurrent_hash_map.hpp:2098
size_type max_size() const
Upper bound on size.
Definition: concurrent_hash_map.hpp:2405
concurrent_hash_map(I first, I last)
Construction table with copying iteration range.
Definition: concurrent_hash_map.hpp:2140
bool insert(const_accessor &result, const Key &key)
Insert item (if not already present) and acquire a read lock on the item.
Definition: concurrent_hash_map.hpp:2564
bool find(const_accessor &result, const K &key) const
Find item and acquire a read lock on the item.
Definition: concurrent_hash_map.hpp:2503
void internal_copy(const concurrent_hash_map &source)
Copy "source" to *this, where *this must start out empty.
Definition: concurrent_hash_map.hpp:3407
concurrent_hash_map & operator=(std::initializer_list< value_type > il)
Assignment Not thread safe.
Definition: concurrent_hash_map.hpp:2260
concurrent_hash_map(std::initializer_list< value_type > il)
Construct table with initializer list.
Definition: concurrent_hash_map.hpp:2152
concurrent_hash_map(concurrent_hash_map &&table)
Move constructor.
Definition: concurrent_hash_map.hpp:2129
bool erase(const K &key)
Remove element with corresponding key.
Definition: concurrent_hash_map.hpp:2911
bool insert_or_assign(const key_type &key, M &&obj)
Inserts item if there is no such key present already, assigns provided value otherwise.
Definition: concurrent_hash_map.hpp:2727
void insert(I first, I last)
Insert range [first, last)
Definition: concurrent_hash_map.hpp:2696
bool insert(accessor &result, const Key &key)
Insert item (if not already present) and acquire a write lock on the item.
Definition: concurrent_hash_map.hpp:2581
bool insert_or_assign(key_type &&key, M &&obj)
Inserts item if there is no such key present already, assigns provided value otherwise.
Definition: concurrent_hash_map.hpp:2755
void runtime_initialize()
Initialize persistent concurrent hash map after process restart.
Definition: concurrent_hash_map.hpp:2170
concurrent_hash_map(const concurrent_hash_map &table)
Copy constructor.
Definition: concurrent_hash_map.hpp:2117
concurrent_hash_map(size_type n)
Construct empty table with n preallocated buckets.
Definition: concurrent_hash_map.hpp:2107
pobj_defrag_result defragment(double start_percent=0, double amount_percent=100)
Defragment the given (by 'start_percent' and 'amount_percent') part of buckets of the hash map.
Definition: concurrent_hash_map.hpp:2843
Defrag class.
Definition: defrag.hpp:83
pobj_defrag_result run()
Starts defragmentation with previously stored pointers.
Definition: defrag.hpp:188
std::enable_if< is_defragmentable< T >), void >::type add(T &t)
Stores address of the referenced object to the defragmentation queue.
Definition: defrag.hpp:112
typename detail::transaction_base< true >::manual manual
C++ manual scope transaction class.
Definition: transaction.hpp:745
static void run(obj::pool_base &pool, std::function< void()> tx, Locks &... locks)
Execute a closure-like transaction and lock locks.
Definition: transaction.hpp:810
Persistent memory resident mutex implementation.
Definition: mutex.hpp:33
Resides on pmem class.
Definition: p.hpp:36
const T & get_ro() const noexcept
Retrieves read-only const reference of the object.
Definition: p.hpp:129
The non-template pool base class.
Definition: pool.hpp:51
Custom transaction error class.
Definition: pexceptions.hpp:167
Commonly used functionality.
Defragmentation class.
A persistent version of thread-local storage.
persistent_ptr transactional allocation functions for objects.
Pmem-resident mutex.
Persistent memory namespace.
Definition: allocation_flag.hpp:15
Resides on pmem property template.
Pair implementation.
Persistent pointer for pool handle.
Persistent smart pointer.
Pmem-resident shared mutex.
Commonly used SFINAE helpers.
C++ pmemobj transactions.