Struct FutexTable 

pub struct FutexTable<Key: FutexKey> { /* private fields */ }

A table of futexes.

Each 32-bit aligned address in an address space can potentially have an associated futex that userspace can wait upon. This table is a sparse representation that has an actual WaitQueue only for those addresses that have ever actually had a futex operation performed on them.

Implementations

impl<Key: FutexKey> FutexTable<Key>

pub fn wait_boot( &self, current_task: &CurrentTask, addr: UserAddress, value: u32, mask: u32, deadline: BootInstant, timer_slack: BootDuration, ) -> Result<(), Errno>

Wait on the futex at the given address given a boot deadline.

See FUTEX_WAIT when passed a deadline in CLOCK_REALTIME.

pub fn wait( &self, current_task: &CurrentTask, addr: UserAddress, value: u32, mask: u32, deadline: MonotonicInstant, ) -> Result<(), Errno>

Wait on the futex at the given address.

See FUTEX_WAIT.

pub fn wake( &self, task: &Task, addr: UserAddress, count: usize, mask: u32, ) -> Result<usize, Errno>

Wake the given number of waiters on futex at the given address. Returns the number of waiters actually woken.

See FUTEX_WAKE.

pub fn requeue( &self, current_task: &CurrentTask, addr: UserAddress, wake_count: usize, requeue_count: usize, new_addr: UserAddress, expected_value: Option<u32>, ) -> Result<usize, Errno>

Requeue the waiters to another address.

See FUTEX_CMP_REQUEUE

pub fn lock_pi( &self, current_task: &CurrentTask, addr: UserAddress, deadline: MonotonicInstant, ) -> Result<(), Errno>

Lock the futex at the given address.

See FUTEX_LOCK_PI.

pub fn unlock_pi( &self, current_task: &CurrentTask, addr: UserAddress, ) -> Result<(), Errno>

Unlock the futex at the given address.

See FUTEX_UNLOCK_PI.

impl FutexTable<SharedFutexKey>

pub fn external_wait( &self, memory: MemoryObject, offset: u64, value: u32, mask: u32, ) -> Result<(Arc<()>, Receiver<()>), Errno>

Wait on the futex at the given offset in the memory.

Returns a receiver that will be signaled when the futex is woken, and an Arc<()> token that must be kept alive by the caller for the duration of the wait. If the caller drops the token (e.g., if the external client disconnects), the waiter is marked as stale and will be garbage-collected by the next futex operation on this table.

See FUTEX_WAIT.

pub fn external_wake( &self, memory: MemoryObject, offset: u64, count: usize, mask: u32, ) -> Result<usize, Errno>

Wake the given number of waiters on futex at the given offset in the memory. Returns the number of waiters actually woken.

See FUTEX_WAKE.

pub fn external_requeue( &self, first_memory: MemoryObject, first_offset: u64, second_memory: Option<MemoryObject>, second_offset: u64, wake_count: usize, requeue_count: usize, expected_value: Option<u32>, ) -> Result<usize, Errno>

Trait Implementations

impl<Key: FutexKey> Default for FutexTable<Key>

fn default() -> Self

Returns the “default value” for a type.