Crate cooptex[−][src]
Expand description
cooptex provides deadlock-free Mutexes. The CoopMutex::lock
method wraps the
std::sync::Mutex
return value with a Result
that will request the caller to drop other held
locks so another thread could make progress. This behavior is easily accomplished by using the
retry_loop
function.
use cooptex::*;
let a = CoopMutex::new(42);
let b = CoopMutex::new(43);
retry_loop(|| {
let a_lock = a.lock()?.unwrap();
let b_lock = b.lock()?.unwrap();
assert_eq!(*a_lock + *b_lock, 85);
Ok(())
});
Guarantees
This crate aims to guarantee that multiple threads cannot possibly deadlock by acquiring locks.
This crate also will prefer threads that have lived the “longest” without completing work.
Meaning, when retry_loop
successfully completes, it will move that thread to the end of the
queue for acquiring future locks. This provides an approximately fair scheduler.
The crate is still in early development, so there may be cases that aren’t covered. Please open an issue if you can reproduce a deadlock.
Non-Guarantees
This crate explicitly allows the following potentially undesired behavior:
CoopMutex::lock
may returnRetry
when it could wait and acquire the lock without a deadlock.CoopMutex::lock
may wait arbitrarily long before returningRetry
.
Incomplete
- We have not fully analyzed the behavior during panics. There is no
unsafe
code, so we could only possibly deadlock.
Structs
Marker struct indicating that a thread requesting a CoopMutex
should drop all its currently
held MutexGuard
s and attempt to reacquire them.
Functions
Helper function for implementing the behavior of dropping held MutexGuard
s when a
CoopMutex::lock
call returns Retry
.