/*
- * Copyright 2012 Facebook, Inc.
+ * Copyright 2012-present Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#error "This should only be included by AtomicHashArray.h"
#endif
-#include "folly/Bits.h"
-#include "folly/detail/AtomicHashUtils.h"
+#include <type_traits>
+
+#include <folly/detail/AtomicHashUtils.h>
+#include <folly/lang/Bits.h>
namespace folly {
// AtomicHashArray private constructor --
-template <class KeyT, class ValueT, class HashFcn>
-AtomicHashArray<KeyT, ValueT, HashFcn>::
+template <
+ class KeyT,
+ class ValueT,
+ class HashFcn,
+ class EqualFcn,
+ class Allocator,
+ class ProbeFcn,
+ class KeyConvertFcn>
+AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn,
+ Allocator, ProbeFcn, KeyConvertFcn>::
AtomicHashArray(size_t capacity, KeyT emptyKey, KeyT lockedKey,
- KeyT erasedKey, double maxLoadFactor, size_t cacheSize)
- : capacity_(capacity), maxEntries_(size_t(maxLoadFactor * capacity_ + 0.5)),
+ KeyT erasedKey, double _maxLoadFactor, uint32_t cacheSize)
+ : capacity_(capacity),
+ maxEntries_(size_t(_maxLoadFactor * capacity_ + 0.5)),
kEmptyKey_(emptyKey), kLockedKey_(lockedKey), kErasedKey_(erasedKey),
kAnchorMask_(nextPowTwo(capacity_) - 1), numEntries_(0, cacheSize),
numPendingEntries_(0, cacheSize), isFull_(0), numErases_(0) {
* of key and returns true, or if key does not exist returns false and
* ret.index is set to capacity_.
*/
-template <class KeyT, class ValueT, class HashFcn>
-typename AtomicHashArray<KeyT, ValueT, HashFcn>::SimpleRetT
-AtomicHashArray<KeyT, ValueT, HashFcn>::
-findInternal(const KeyT key_in) {
- DCHECK_NE(key_in, kEmptyKey_);
- DCHECK_NE(key_in, kLockedKey_);
- DCHECK_NE(key_in, kErasedKey_);
- for (size_t idx = keyToAnchorIdx(key_in), numProbes = 0;
+template <
+ class KeyT,
+ class ValueT,
+ class HashFcn,
+ class EqualFcn,
+ class Allocator,
+ class ProbeFcn,
+ class KeyConvertFcn>
+template <class LookupKeyT, class LookupHashFcn, class LookupEqualFcn>
+typename AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn,
+ Allocator, ProbeFcn, KeyConvertFcn>::SimpleRetT
+AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn,
+ Allocator, ProbeFcn, KeyConvertFcn>::
+findInternal(const LookupKeyT key_in) {
+ checkLegalKeyIfKey<LookupKeyT>(key_in);
+
+ for (size_t idx = keyToAnchorIdx<LookupKeyT, LookupHashFcn>(key_in),
+ numProbes = 0;
;
- idx = probeNext(idx, numProbes)) {
- const KeyT key = relaxedLoadKey(cells_[idx]);
- if (LIKELY(key == key_in)) {
+ idx = ProbeFcn()(idx, numProbes, capacity_)) {
+ const KeyT key = acquireLoadKey(cells_[idx]);
+ if (LIKELY(LookupEqualFcn()(key, key_in))) {
return SimpleRetT(idx, true);
}
if (UNLIKELY(key == kEmptyKey_)) {
// if we hit an empty element, this key does not exist
return SimpleRetT(capacity_, false);
}
+ // NOTE: the way we count numProbes must be same in find(), insert(),
+ // and erase(). Otherwise it may break probing.
++numProbes;
if (UNLIKELY(numProbes >= capacity_)) {
// probed every cell...fail
* this will be the previously inserted value, and if the map is full it is
* default.
*/
-template <class KeyT, class ValueT, class HashFcn>
-typename AtomicHashArray<KeyT, ValueT, HashFcn>::SimpleRetT
-AtomicHashArray<KeyT, ValueT, HashFcn>::
-insertInternal(const value_type& record) {
+template <
+ class KeyT,
+ class ValueT,
+ class HashFcn,
+ class EqualFcn,
+ class Allocator,
+ class ProbeFcn,
+ class KeyConvertFcn>
+template <
+ typename LookupKeyT,
+ typename LookupHashFcn,
+ typename LookupEqualFcn,
+ typename LookupKeyToKeyFcn,
+ typename... ArgTs>
+typename AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn,
+ Allocator, ProbeFcn, KeyConvertFcn>::SimpleRetT
+AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn,
+ Allocator, ProbeFcn, KeyConvertFcn>::
+insertInternal(LookupKeyT key_in, ArgTs&&... vCtorArgs) {
const short NO_NEW_INSERTS = 1;
const short NO_PENDING_INSERTS = 2;
- const KeyT key_in = record.first;
- CHECK_NE(key_in, kEmptyKey_);
- CHECK_NE(key_in, kLockedKey_);
- CHECK_NE(key_in, kErasedKey_);
- for (size_t idx = keyToAnchorIdx(key_in), numProbes = 0;
- ;
- idx = probeNext(idx, numProbes)) {
+ checkLegalKeyIfKey<LookupKeyT>(key_in);
+
+ size_t idx = keyToAnchorIdx<LookupKeyT, LookupHashFcn>(key_in);
+ size_t numProbes = 0;
+ for (;;) {
DCHECK_LT(idx, capacity_);
value_type* cell = &cells_[idx];
if (relaxedLoadKey(*cell) == kEmptyKey_) {
// another thread now does ++numPendingEntries_, we expect it
// to pass the isFull_.load() test above. (It shouldn't insert
// a new entry.)
- FOLLY_SPIN_WAIT(
- isFull_.load(std::memory_order_acquire) != NO_PENDING_INSERTS
- && numPendingEntries_.readFull() != 0
- );
+ detail::atomic_hash_spin_wait([&] {
+ return
+ (isFull_.load(std::memory_order_acquire) != NO_PENDING_INSERTS) &&
+ (numPendingEntries_.readFull() != 0);
+ });
isFull_.store(NO_PENDING_INSERTS, std::memory_order_release);
if (relaxedLoadKey(*cell) == kEmptyKey_) {
// If we fail, fall through to comparison below; maybe the insert that
// just beat us was for this very key....
if (tryLockCell(cell)) {
+ KeyT key_new;
// Write the value - done before unlocking
try {
+ key_new = LookupKeyToKeyFcn()(key_in);
+ typedef typename std::remove_const<LookupKeyT>::type
+ LookupKeyTNoConst;
+ constexpr bool kAlreadyChecked =
+ std::is_same<KeyT, LookupKeyTNoConst>::value;
+ if (!kAlreadyChecked) {
+ checkLegalKeyIfKey(key_new);
+ }
DCHECK(relaxedLoadKey(*cell) == kLockedKey_);
- /*
- * This happens using the copy constructor because we won't have
- * constructed a lhs to use an assignment operator on when
- * values are being set.
- */
- new (&cell->second) ValueT(record.second);
- unlockCell(cell, key_in); // Sets the new key
+ // A const mapped_type is only constant once constructed, so cast
+ // away any const for the placement new here.
+ using mapped = typename std::remove_const<mapped_type>::type;
+ new (const_cast<mapped*>(&cell->second))
+ ValueT(std::forward<ArgTs>(vCtorArgs)...);
+ unlockCell(cell, key_new); // Sets the new key
} catch (...) {
+ // Transition back to empty key---requires handling
+ // locked->empty below.
unlockCell(cell, kEmptyKey_);
--numPendingEntries_;
throw;
}
- DCHECK(relaxedLoadKey(*cell) == key_in);
+ // An erase() can race here and delete right after our insertion
+ // Direct comparison rather than EqualFcn ok here
+ // (we just inserted it)
+ DCHECK(relaxedLoadKey(*cell) == key_new ||
+ relaxedLoadKey(*cell) == kErasedKey_);
--numPendingEntries_;
++numEntries_; // This is a thread cached atomic increment :)
if (numEntries_.readFast() >= maxEntries_) {
}
}
DCHECK(relaxedLoadKey(*cell) != kEmptyKey_);
- if (kLockedKey_ == cellKeyPtr(*cell)->load(std::memory_order_acquire)) {
- FOLLY_SPIN_WAIT(
- kLockedKey_ == cellKeyPtr(*cell)->load(std::memory_order_acquire)
- );
+ if (kLockedKey_ == acquireLoadKey(*cell)) {
+ detail::atomic_hash_spin_wait([&] {
+ return kLockedKey_ == acquireLoadKey(*cell);
+ });
}
- DCHECK(relaxedLoadKey(*cell) != kEmptyKey_);
- DCHECK(relaxedLoadKey(*cell) != kLockedKey_);
- if (key_in == relaxedLoadKey(*cell)) {
+
+ const KeyT thisKey = acquireLoadKey(*cell);
+ if (LookupEqualFcn()(thisKey, key_in)) {
// Found an existing entry for our key, but we don't overwrite the
// previous value.
return SimpleRetT(idx, false);
+ } else if (thisKey == kEmptyKey_ || thisKey == kLockedKey_) {
+ // We need to try again (i.e., don't increment numProbes or
+ // advance idx): this case can happen if the constructor for
+ // ValueT threw for this very cell (the rethrow block above).
+ continue;
}
+
+
+ // NOTE: the way we count numProbes must be same in find(),
+ // insert(), and erase(). Otherwise it may break probing.
++numProbes;
if (UNLIKELY(numProbes >= capacity_)) {
// probed every cell...fail
return SimpleRetT(capacity_, false);
}
+
+ idx = ProbeFcn()(idx, numProbes, capacity_);
}
}
-
/*
* erase --
*
* erased key will never be reused. If there's an associated value, we won't
* touch it either.
*/
-template <class KeyT, class ValueT, class HashFcn>
-size_t AtomicHashArray<KeyT, ValueT, HashFcn>::
+template <
+ class KeyT,
+ class ValueT,
+ class HashFcn,
+ class EqualFcn,
+ class Allocator,
+ class ProbeFcn,
+ class KeyConvertFcn>
+size_t AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn,
+ Allocator, ProbeFcn, KeyConvertFcn>::
erase(KeyT key_in) {
CHECK_NE(key_in, kEmptyKey_);
CHECK_NE(key_in, kLockedKey_);
CHECK_NE(key_in, kErasedKey_);
+
for (size_t idx = keyToAnchorIdx(key_in), numProbes = 0;
;
- idx = probeNext(idx, numProbes)) {
+ idx = ProbeFcn()(idx, numProbes, capacity_)) {
DCHECK_LT(idx, capacity_);
value_type* cell = &cells_[idx];
- if (relaxedLoadKey(*cell) == kEmptyKey_ ||
- relaxedLoadKey(*cell) == kLockedKey_) {
+ KeyT currentKey = acquireLoadKey(*cell);
+ if (currentKey == kEmptyKey_ || currentKey == kLockedKey_) {
// If we hit an empty (or locked) element, this key does not exist. This
// is similar to how it's handled in find().
return 0;
}
- if (key_in == relaxedLoadKey(*cell)) {
+ if (EqualFcn()(currentKey, key_in)) {
// Found an existing entry for our key, attempt to mark it erased.
// Some other thread may have erased our key, but this is ok.
- KeyT expect = key_in;
+ KeyT expect = currentKey;
if (cellKeyPtr(*cell)->compare_exchange_strong(expect, kErasedKey_)) {
numErases_.fetch_add(1, std::memory_order_relaxed);
// If another thread succeeds in erasing our key, we'll stop our search.
return 0;
}
+
+ // NOTE: the way we count numProbes must be same in find(), insert(),
+ // and erase(). Otherwise it may break probing.
++numProbes;
if (UNLIKELY(numProbes >= capacity_)) {
// probed every cell...fail
}
}
-template <class KeyT, class ValueT, class HashFcn>
-const typename AtomicHashArray<KeyT, ValueT, HashFcn>::Config
-AtomicHashArray<KeyT, ValueT, HashFcn>::defaultConfig;
-
-template <class KeyT, class ValueT, class HashFcn>
-typename AtomicHashArray<KeyT, ValueT, HashFcn>::SmartPtr
-AtomicHashArray<KeyT, ValueT, HashFcn>::
+template <
+ class KeyT,
+ class ValueT,
+ class HashFcn,
+ class EqualFcn,
+ class Allocator,
+ class ProbeFcn,
+ class KeyConvertFcn>
+typename AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn,
+ Allocator, ProbeFcn, KeyConvertFcn>::SmartPtr
+AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn,
+ Allocator, ProbeFcn, KeyConvertFcn>::
create(size_t maxSize, const Config& c) {
CHECK_LE(c.maxLoadFactor, 1.0);
CHECK_GT(c.maxLoadFactor, 0.0);
size_t capacity = size_t(maxSize / c.maxLoadFactor);
size_t sz = sizeof(AtomicHashArray) + sizeof(value_type) * capacity;
- std::unique_ptr<void, void(*)(void*)> mem(malloc(sz), free);
- new(mem.get()) AtomicHashArray(capacity, c.emptyKey, c.lockedKey, c.erasedKey,
- c.maxLoadFactor, c.entryCountThreadCacheSize);
- SmartPtr map(static_cast<AtomicHashArray*>(mem.release()));
+ auto const mem = Allocator().allocate(sz);
+ try {
+ new (mem) AtomicHashArray(capacity, c.emptyKey, c.lockedKey, c.erasedKey,
+ c.maxLoadFactor, c.entryCountThreadCacheSize);
+ } catch (...) {
+ Allocator().deallocate(mem, sz);
+ throw;
+ }
+
+ SmartPtr map(static_cast<AtomicHashArray*>((void *)mem));
/*
* Mark all cells as empty.
return map;
}
-template <class KeyT, class ValueT, class HashFcn>
-void AtomicHashArray<KeyT, ValueT, HashFcn>::
+template <
+ class KeyT,
+ class ValueT,
+ class HashFcn,
+ class EqualFcn,
+ class Allocator,
+ class ProbeFcn,
+ class KeyConvertFcn>
+void AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn,
+ Allocator, ProbeFcn, KeyConvertFcn>::
destroy(AtomicHashArray* p) {
assert(p);
+
+ size_t sz = sizeof(AtomicHashArray) + sizeof(value_type) * p->capacity_;
+
FOR_EACH_RANGE(i, 0, p->capacity_) {
if (p->cells_[i].first != p->kEmptyKey_) {
p->cells_[i].~value_type();
}
}
p->~AtomicHashArray();
- free(p);
+
+ Allocator().deallocate((char *)p, sz);
}
// clear -- clears all keys and values in the map and resets all counters
-template <class KeyT, class ValueT, class HashFcn>
-void AtomicHashArray<KeyT, ValueT, HashFcn>::
+template <
+ class KeyT,
+ class ValueT,
+ class HashFcn,
+ class EqualFcn,
+ class Allocator,
+ class ProbeFcn,
+ class KeyConvertFcn>
+void AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn,
+ Allocator, ProbeFcn, KeyConvertFcn>::
clear() {
FOR_EACH_RANGE(i, 0, capacity_) {
if (cells_[i].first != kEmptyKey_) {
// Iterator implementation
-template <class KeyT, class ValueT, class HashFcn>
+template <
+ class KeyT,
+ class ValueT,
+ class HashFcn,
+ class EqualFcn,
+ class Allocator,
+ class ProbeFcn,
+ class KeyConvertFcn>
template <class ContT, class IterVal>
-struct AtomicHashArray<KeyT, ValueT, HashFcn>::aha_iterator
+struct AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn,
+ Allocator, ProbeFcn, KeyConvertFcn>::
+ aha_iterator
: boost::iterator_facade<aha_iterator<ContT,IterVal>,
IterVal,
boost::forward_traversal_tag>
{
- explicit aha_iterator() : aha_(0) {}
+ explicit aha_iterator() : aha_(nullptr) {}
// Conversion ctor for interoperability between const_iterator and
// iterator. The enable_if<> magic keeps us well-behaved for
// is_convertible<> (v. the iterator_facade documentation).
- template<class OtherContT, class OtherVal>
- aha_iterator(const aha_iterator<OtherContT,OtherVal>& o,
- typename std::enable_if<
- std::is_convertible<OtherVal*,IterVal*>::value >::type* = 0)
- : aha_(o.aha_)
- , offset_(o.offset_)
- {}
+ template <class OtherContT, class OtherVal>
+ aha_iterator(
+ const aha_iterator<OtherContT, OtherVal>& o,
+ typename std::enable_if<
+ std::is_convertible<OtherVal*, IterVal*>::value>::type* = nullptr)
+ : aha_(o.aha_), offset_(o.offset_) {}
explicit aha_iterator(ContT* array, size_t offset)
: aha_(array)
, offset_(offset)
- {
- advancePastEmpty();
- }
+ {}
// Returns unique index that can be used with findAt().
// WARNING: The following function will fail silently for hashtable
// with capacity > 2^32
uint32_t getIndex() const { return offset_; }
+ void advancePastEmpty() {
+ while (offset_ < aha_->capacity_ && !isValid()) {
+ ++offset_;
+ }
+ }
+
private:
friend class AtomicHashArray;
friend class boost::iterator_core_access;
return aha_->cells_[offset_];
}
- void advancePastEmpty() {
- while (offset_ < aha_->capacity_ && !isValid()) {
- ++offset_;
- }
- }
-
bool isValid() const {
- KeyT key = relaxedLoadKey(aha_->cells_[offset_]);
+ KeyT key = acquireLoadKey(aha_->cells_[offset_]);
return key != aha_->kEmptyKey_ &&
key != aha_->kLockedKey_ &&
key != aha_->kErasedKey_;
}; // aha_iterator
} // namespace folly
-
-#undef FOLLY_SPIN_WAIT
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