Struct io_uring::Parameters

pub struct Parameters(_);

Implementations

impl Parameters

pub fn is_setup_sqpoll(&self) -> bool

pub fn is_setup_iopoll(&self) -> bool

pub fn is_feature_single_mmap(&self) -> bool

If this flag is set, the two SQ and CQ rings can be mapped with a single mmap(2) call. The SQEs must still be allocated separately. This brings the necessary mmap(2) calls down from three to two.

pub fn is_feature_nodrop(&self) -> bool

If this flag is set, io_uring supports never dropping completion events. If a completion event occurs and the CQ ring is full, the kernel stores the event internally until such a time that the CQ ring has room for more entries.

pub fn is_feature_submit_stable(&self) -> bool

If this flag is set, applications can be certain that any data for async offload has been consumed when the kernel has consumed the SQE

pub fn is_feature_rw_cur_pos(&self) -> bool

If this flag is set, applications can specify offset == -1 with IORING_OP_{READV,WRITEV}, IORING_OP_{READ,WRITE}_FIXED, and IORING_OP_{READ,WRITE} to mean current file position, which behaves like preadv2(2) and pwritev2(2) with offset == -1. It’ll use (and update) the current file position.

This obviously comes with the caveat that if the application has multiple reads or writes in flight, then the end result will not be as expected. This is similar to threads sharing a file descriptor and doing IO using the current file position.

pub fn is_feature_cur_personality(&self) -> bool

If this flag is set, then io_uring guarantees that both sync and async execution of a request assumes the credentials of the task that called io_uring_enter(2) to queue the requests. If this flag isn’t set, then requests are issued with the credentials of the task that originally registered the io_uring. If only one task is using a ring, then this flag doesn’t matter as the credentials will always be the same. Note that this is the default behavior, tasks can still register different personalities through io_uring_register(2) with IORING_REGISTER_PERSONALITY and specify the personality to use in the sqe.

pub fn is_feature_fast_poll(&self) -> bool

pub fn sq_entries(&self) -> u32

pub fn cq_entries(&self) -> u32

Trait Implementations

impl Clone for Parameters

fn clone(&self) -> Parameters

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.