Enum VirtualMemoryError 

pub enum VirtualMemoryError {
    Misaligned {
        what: &'static str,
        value: usize,
        granularity: usize,
        rounded: usize,
    },
    Delegated {
        operation: &'static str,
        source: Box<dyn Error + Send + Sync>,
    },
    Os {
        operation: &'static str,
        reason: String,
        code: i32,
    },
    OutOfRange {
        offset: usize,
        length: usize,
        reserved: usize,
        overrun: usize,
    },
    AlreadyMapped {
        offset: usize,
    },
    LocationMismatch {
        requested: String,
        actual: String,
    },
}

Why a virtual range could not be reserved, mapped, or unmapped.

Not Clone/PartialEq: a refusal that carries the cause underneath it cannot be meaningfully duplicated or compared, and keeping the cause is worth more than either.

Variants

Misaligned

The requested size or offset is not a multiple of the mapping granularity.

Reported rather than rounded, because silently rounding an offset would place a block somewhere the caller did not ask for and every subsequent read would be of the wrong data.

Fields

what: &'static str

Which quantity was misaligned.

value: usize

The value supplied.

granularity: usize

This platform’s granularity.

rounded: usize

The next legal value at or above value.

Delegated

A layer this call delegated to refused the request.

Distinct from VirtualMemoryError::Os, which means the kernel refused it. Keeping the two apart matters because they call for opposite responses: a governor that declines a reservation is telling the caller to ask for less or free something first, while a driver that fails a mapping is telling it that the request cannot be served at all. Flattening a decision into an OS error also has to invent an errno, and os error 0 in a log sends the next reader hunting for a kernel fault that never happened.

The refusal is kept whole rather than stringified so callers can still match on it after it has crossed this boundary.

Fields

operation: &'static str

Which call was being made when the lower layer refused.

source: Box<dyn Error + Send + Sync>

The refusal itself, kept whole so it survives downcast_ref.

Os

The operating system refused the request.

Fields

operation: &'static str

Which call failed.

reason: String

What the OS reported.

code: i32

The raw error code.

OutOfRange

A mapping would fall outside the reserved range.

Fields

offset: usize

Where the caller asked to map.

length: usize

How much.

reserved: usize

The reservation’s size.

overrun: usize

How far past the end it would reach.

AlreadyMapped

The range is already mapped at that offset.

Replacing a live mapping silently would leave the previous block allocated but unreachable, so it is refused.

Fields

offset: usize

The offset in question.

LocationMismatch

A caller-supplied PhysicalLocation (or platform-specific stand-in for it) did not match the physical backing a pool/handle actually holds.

Rejected before any lease charge, handle acquisition, mapping, or accounting mutation happens: this is a caller-programming-error check, not a driver refusal, and must not have any side effect on the pool it was refused against.

Fields

requested: String

What the caller asked to commit against.

actual: String

What the pool is actually backed by.

Trait Implementations

impl Debug for VirtualMemoryError

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Display for VirtualMemoryError

fn fmt(&self, __formatter: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Error for VirtualMemoryError

fn source(&self) -> Option<&(dyn Error + 'static)>

Returns the lower-level source of this error, if any.

fn description(&self) -> &str

👎Deprecated since 1.42.0:

use the Display impl or to_string()

fn cause(&self) -> Option<&dyn Error>

👎Deprecated since 1.33.0:

replaced by Error::source, which can support downcasting

fn provide<'a>(&'a self, request: &mut Request<'a>)

🔬This is a nightly-only experimental API. (error_generic_member_access)

Provides type-based access to context intended for error reports.

impl From<VirtualMemoryError> for VirtualBufferError

fn from(source: VirtualMemoryError) -> Self

Converts to this type from the input type.