commit | c35a0e4a480265385a38c22e022c7c62eb26d0a2 | [log] [tgz] |
---|---|---|
author | android-build-team Robot <android-build-team-robot@google.com> | Fri Apr 30 01:06:13 2021 +0000 |
committer | android-build-team Robot <android-build-team-robot@google.com> | Fri Apr 30 01:06:13 2021 +0000 |
tree | 8aa33bfe69d31d520c9f1aa0b31ed2e4683f5595 | |
parent | c9ca34617ae8de403c5af860d705a3c875cab17f [diff] | |
parent | 0508ccd77663713347040e849ad3e1fc97bf495d [diff] |
Snap for 7325096 from 0508ccd77663713347040e849ad3e1fc97bf495d to sc-d1-release Change-Id: I3f3fc2abe1850f87596e41cf0e1733d00aece985
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
).