Struct parking_lot::raw_mutex::RawMutex

pub struct RawMutex {
    state: AtomicU8,
}

Raw mutex type backed by the parking lot.

Fields

state: AtomicU8

This atomic integer holds the current state of the mutex instance. Only the two lowest bits are used. See LOCKED_BIT and PARKED_BIT for the bitmask for these bits.

State table:

PARKED_BIT | LOCKED_BIT | Description 0 | 0 | The mutex is not locked, nor is anyone waiting for it. ———–+————+—————————————————————— 0 | 1 | The mutex is locked by exactly one thread. No other thread is | | waiting for it. ———–+————+—————————————————————— 1 | 0 | The mutex is not locked. One or more thread is parked or about to | | park. At least one of the parked threads are just about to be | | unparked, or a thread heading for parking might abort the park. ———–+————+—————————————————————— 1 | 1 | The mutex is locked by exactly one thread. One or more thread is | | parked or about to park, waiting for the lock to become available. | | In this state, PARKED_BIT is only ever cleared when a bucket lock | | is held (i.e. in a parking_lot_core callback). This ensures that | | we never end up in a situation where there are parked threads but | | PARKED_BIT is not set (which would result in those threads | | potentially never getting woken up).

Implementations

impl RawMutex

pub(crate) fn mark_parked_if_locked(&self) -> bool

pub(crate) fn mark_parked(&self)

fn lock_slow(&self, timeout: Option<Instant>) -> bool

fn unlock_slow(&self, force_fair: bool)

fn bump_slow(&self)

Trait Implementations

impl RawMutex for RawMutex

const INIT: RawMutex = _

Initial value for an unlocked mutex.

type GuardMarker = GuardNoSend

Marker type which determines whether a lock guard should be Send. Use one of the GuardSend or GuardNoSend helper types here.

fn lock(&self)

Acquires this mutex, blocking the current thread until it is able to do so.

fn try_lock(&self) -> bool

Attempts to acquire this mutex without blocking. Returns true if the lock was successfully acquired and false otherwise.

unsafe fn unlock(&self)

Unlocks this mutex.

fn is_locked(&self) -> bool

Checks whether the mutex is currently locked.

impl RawMutexFair for RawMutex

unsafe fn unlock_fair(&self)

Unlocks this mutex using a fair unlock protocol.

unsafe fn bump(&self)

Temporarily yields the mutex to a waiting thread if there is one.

impl RawMutexTimed for RawMutex

type Duration = Duration

Duration type used for try_lock_for.

type Instant = Instant

Instant type used for try_lock_until.

fn try_lock_until(&self, timeout: Instant) -> bool

Attempts to acquire this lock until a timeout is reached.

fn try_lock_for(&self, timeout: Duration) -> bool

Attempts to acquire this lock until a timeout is reached.