| // Copyright 2016 Amanieu d'Antras |
| // |
| // Licensed under the Apache License, Version 2.0, <LICENSE-APACHE or |
| // http://apache.org/licenses/LICENSE-2.0> or the MIT license <LICENSE-MIT or |
| // http://opensource.org/licenses/MIT>, at your option. This file may not be |
| // copied, modified, or distributed except according to those terms. |
| |
| //! This library exposes a low-level API for creating your own efficient |
| //! synchronization primitives. |
| //! |
| //! # The parking lot |
| //! |
| //! To keep synchronization primitives small, all thread queuing and suspending |
| //! functionality is offloaded to the *parking lot*. The idea behind this is based |
| //! on the Webkit [`WTF::ParkingLot`](https://webkit.org/blog/6161/locking-in-webkit/) |
| //! class, which essentially consists of a hash table mapping of lock addresses |
| //! to queues of parked (sleeping) threads. The Webkit parking lot was itself |
| //! inspired by Linux [futexes](http://man7.org/linux/man-pages/man2/futex.2.html), |
| //! but it is more powerful since it allows invoking callbacks while holding a |
| //! queue lock. |
| //! |
| //! There are two main operations that can be performed on the parking lot: |
| //! |
| //! - *Parking* refers to suspending the thread while simultaneously enqueuing it |
| //! on a queue keyed by some address. |
| //! - *Unparking* refers to dequeuing a thread from a queue keyed by some address |
| //! and resuming it. |
| //! |
| //! See the documentation of the individual functions for more details. |
| //! |
| //! # Building custom synchronization primitives |
| //! |
| //! Building custom synchronization primitives is very simple since the parking |
| //! lot takes care of all the hard parts for you. A simple example for a |
| //! custom primitive would be to integrate a `Mutex` inside another data type. |
| //! Since a mutex only requires 2 bits, it can share space with other data. |
| //! For example, one could create an `ArcMutex` type that combines the atomic |
| //! reference count and the two mutex bits in the same atomic word. |
| |
| #![warn(missing_docs)] |
| #![warn(rust_2018_idioms)] |
| #![cfg_attr( |
| all(target_env = "sgx", target_vendor = "fortanix"), |
| feature(sgx_platform) |
| )] |
| #![cfg_attr( |
| all( |
| feature = "nightly", |
| target_family = "wasm", |
| target_feature = "atomics" |
| ), |
| feature(stdsimd) |
| )] |
| |
| mod parking_lot; |
| mod spinwait; |
| mod thread_parker; |
| mod util; |
| mod word_lock; |
| |
| pub use self::parking_lot::deadlock; |
| pub use self::parking_lot::{park, unpark_all, unpark_filter, unpark_one, unpark_requeue}; |
| pub use self::parking_lot::{ |
| FilterOp, ParkResult, ParkToken, RequeueOp, UnparkResult, UnparkToken, |
| }; |
| pub use self::parking_lot::{DEFAULT_PARK_TOKEN, DEFAULT_UNPARK_TOKEN}; |
| pub use self::spinwait::SpinWait; |