/*
- * Copyright 2014 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 <type_traits>
+
#include <folly/detail/AtomicHashUtils.h>
+#include <folly/lang/Bits.h>
namespace folly {
// AtomicHashArray private constructor --
-template <class KeyT, class ValueT,
- class HashFcn, class EqualFcn, class Allocator>
-AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn, Allocator>::
+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, class EqualFcn, class Allocator>
-typename AtomicHashArray<KeyT, ValueT,
- HashFcn, EqualFcn, Allocator>::SimpleRetT
-AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn, Allocator>::
-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)) {
+ idx = ProbeFcn()(idx, numProbes, capacity_)) {
const KeyT key = acquireLoadKey(cells_[idx]);
- if (LIKELY(EqualFcn()(key, key_in))) {
+ 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, class EqualFcn, class Allocator>
-template <class T>
-typename AtomicHashArray<KeyT, ValueT,
- HashFcn, EqualFcn, Allocator>::SimpleRetT
-AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn, Allocator>::
-insertInternal(KeyT key_in, T&& value) {
+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;
- CHECK_NE(key_in, kEmptyKey_);
- CHECK_NE(key_in, kLockedKey_);
- CHECK_NE(key_in, kErasedKey_);
+ checkLegalKeyIfKey<LookupKeyT>(key_in);
- size_t idx = keyToAnchorIdx(key_in);
+ size_t idx = keyToAnchorIdx<LookupKeyT, LookupHashFcn>(key_in);
size_t numProbes = 0;
for (;;) {
DCHECK_LT(idx, capacity_);
// 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(std::forward<T>(value));
- 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.
--numPendingEntries_;
throw;
}
+ // 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_in);
+ 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_ == acquireLoadKey(*cell)) {
- FOLLY_SPIN_WAIT(
- kLockedKey_ == acquireLoadKey(*cell)
- );
+ detail::atomic_hash_spin_wait([&] {
+ return kLockedKey_ == acquireLoadKey(*cell);
+ });
}
const KeyT thisKey = acquireLoadKey(*cell);
- if (EqualFcn()(thisKey, key_in)) {
+ if (LookupEqualFcn()(thisKey, key_in)) {
// Found an existing entry for our key, but we don't overwrite the
// previous value.
return SimpleRetT(idx, false);
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 = probeNext(idx, numProbes);
+ 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, class EqualFcn, class Allocator>
-size_t AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn, Allocator>::
+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];
KeyT currentKey = acquireLoadKey(*cell);
// 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, class EqualFcn, class Allocator>
-const typename AtomicHashArray<KeyT, ValueT,
- HashFcn, EqualFcn, Allocator>::Config
-AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn, Allocator>::defaultConfig;
-
-template <class KeyT, class ValueT,
- class HashFcn, class EqualFcn, class Allocator>
-typename AtomicHashArray<KeyT, ValueT,
- HashFcn, EqualFcn, Allocator>::SmartPtr
-AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn, Allocator>::
+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);
return map;
}
-template <class KeyT, class ValueT,
- class HashFcn, class EqualFcn, class Allocator>
-void AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn, Allocator>::
+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);
}
// clear -- clears all keys and values in the map and resets all counters
-template <class KeyT, class ValueT,
- class HashFcn, class EqualFcn, class Allocator>
-void AtomicHashArray<KeyT, ValueT, HashFcn, EqualFcn, Allocator>::
+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, class EqualFcn, class Allocator>
+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, EqualFcn, Allocator>::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 = acquireLoadKey(aha_->cells_[offset_]);
return key != aha_->kEmptyKey_ &&
}; // aha_iterator
} // namespace folly
-
-#undef FOLLY_SPIN_WAIT
projects / folly.git / blobdiff