Class ThreadSafeFreelist

• Defined in File pool_allocator.hpp

Nested Relationships

Nested Types

• Struct ThreadSafeFreelist::HeadPtr

• Struct ThreadSafeFreelist::Node

Class Documentation

class wrench::ThreadSafeFreelist

This type is a thread-safe freelist implementation. It’s lock-free, and uses atomics to control access to the nodes in the freelist.

Use this only when data needs to be shared across threads, and even so, compare the performance against other allocators with a locking policy, such as the single-threaded Freelist with a spinlock.

Benchmark this against other options.

Also consider using thread-local freelists with a common arena, with this as a fallback.

Public Functions

ThreadSafeFreelist() noexcept = default

Default constructor.

ThreadSafeFreelist(const void *start, const void *end, size_t element_size, size_t alignment) noexcept

Constructor to initialize the freelist with the start and end of the arena from which elements can be stored.

Parameters

• start: The start of the arena.

• end: The end of the arena.

• element_size: The size of the elements in the freelist.

• alignment: The alignment of the elements.

ThreadSafeFreelist(ThreadSafeFreelist &&other) noexcept

Move constructor to move other to this freelist.

Parameters

• other: The other freelist to move.

auto operator= (ThreadSafeFreelist &&other) noexcept -> ThreadSafeFreelist &

Move assignment to move other to this freelist.

Parameters

• other: The other freelist to move.

ThreadSafeFreelist(const ThreadSafeFreelist&) = delete

Copy constructor deleted since the freelist can’t be copied.

auto operator= (const ThreadSafeFreelist &) -> ThreadSafeFreelist &=delete

Copy assignment deleted since the freelist can’t be copied.

auto pop_front () noexcept -> void *

Pops the most recently added element from the list, and returns it. If there are no elements left in the list, this returns a nullptr.

auto push_front (void *ptr) noexcept -> void

Pushes the ptr onto the front of the free list.

Parameters

• ptr: The pointer to push onto the front.

Public Static Attributes

constexpr bool resettable = false

Specifies that the freelist is not resettable.