commit | 6ca4b2f1a1ea93fc7e1b10e7b40a14c355a2a2d1 | [log] [tgz] |
---|---|---|
author | Bernie Innocenti <codewiz@google.com> | Tue Dec 15 16:14:05 2020 +0000 |
committer | Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com> | Tue Dec 15 16:14:05 2020 +0000 |
tree | 5421f883b7d1390c46a93ccc361071b9e8b13be4 | |
parent | 117dd39c0f677bf32ce0bfd98b16603830a4caae [diff] | |
parent | 69d600241563ec011fe620c9cfe465e194f36ba5 [diff] |
Allow using spin from DnsResolver am: 60859b459d am: c2303d96a0 am: 69d6002415 Original change: https://android-review.googlesource.com/c/platform/external/rust/crates/spin/+/1528089 MUST ONLY BE SUBMITTED BY AUTOMERGER Change-Id: I9a136ebcbe0b176f5e3444fe33c880b4a65b2cf4
Spin-based synchronization primitives.
This crate provides spin-based versions of the primitives in std::sync
. Because synchronization is done through spinning, the primitives are suitable for use in no_std
environments.
Before deciding to use spin
, we recommend reading this superb blog post by @matklad that discusses the pros and cons of spinlocks. If you have access to std
, it's likely that the primitives in std::sync
will serve you better except in very specific circumstances.
Mutex
, RwLock
and Once
equivalentsno_std
environmentslock_api
compatibilityRwLock
guardsstd
feature to enable yield to the OS scheduler in busy loopsMutex
can become a ticket lockInclude the following under the [dependencies]
section in your Cargo.toml
file.
spin = "x.y"
When calling lock
on a Mutex
you will get a guard value that provides access to the data. When this guard is dropped, the lock will be unlocked.
extern crate spin; use std::{sync::Arc, thread}; fn main() { let counter = Arc::new(spin::Mutex::new(0)); let thread = thread::spawn({ let counter = counter.clone(); move || { for _ in 0..10 { *counter.lock() += 1; } } }); for _ in 0..10 { *counter.lock() += 1; } thread.join().unwrap(); assert_eq!(*counter.lock(), 20); }
The crate comes with a few feature flags that you may wish to use.
lock_api
enabled support for lock_api
ticket_mutex
uses a ticket lock for the implementation of Mutex
std
enables support for thread yielding instead of spinning
It is often desirable to have a lock shared between threads. Wrapping the lock in an std::sync::Arc
is route through which this might be achieved.
Locks provide zero-overhead access to their data when accessed through a mutable reference by using their get_mut
methods.
The behaviour of these lock is similar to their namesakes in std::sync
. they differ on the following:
spin
is distributed under the MIT License, (See LICENSE
).