Struct rarena_allocator::MmapOptions

pub struct MmapOptions(/* private fields */);

Available on crate feature memmap and non-target_family="wasm" only.

A memory map options for file backed SkipMap, providing advanced options and flags for specifying memory map behavior.

Implementations

impl MmapOptions

pub fn new() -> Self

Creates a new set of options for configuring and creating a memory map.

Example

use rarena_allocator::MmapOptions;

// Create a new memory map options.
let mut mmap_options = MmapOptions::new();

pub fn len(self, len: u32) -> Self

Configures the created memory mapped buffer to be len bytes long.

This option is mandatory for anonymous memory maps.

For file-backed memory maps, the length will default to the file length.

Example

use rarena_allocator::MmapOptions;

let opts = MmapOptions::new().len(9);

pub fn offset(self, offset: u32) -> Self

Configures the memory map to start at byte offset from the beginning of the file.

This option has no effect on anonymous memory maps.

By default, the offset is 0.

Example

use rarena_allocator::MmapOptions;

let opts = MmapOptions::new().offset(30);

pub fn stack(self) -> Self

Configures the anonymous memory map to be suitable for a process or thread stack.

This option corresponds to the MAP_STACK flag on Linux. It has no effect on Windows.

This option has no effect on file-backed memory maps.

Example

use rarena_allocator::MmapOptions;

let stack = MmapOptions::new().stack();

pub fn huge(self, page_bits: Option<u8>) -> Self

Configures the anonymous memory map to be allocated using huge pages.

This option corresponds to the MAP_HUGETLB flag on Linux. It has no effect on Windows.

The size of the requested page can be specified in page bits. If not provided, the system default is requested. The requested length should be a multiple of this, or the mapping will fail.

This option has no effect on file-backed memory maps.

Example

use rarena_allocator::MmapOptions;

let stack = MmapOptions::new().huge(Some(21)).len(2*1024*1024);

pub fn populate(self) -> Self

Populate (prefault) page tables for a mapping.

For a file mapping, this causes read-ahead on the file. This will help to reduce blocking on page faults later.

This option corresponds to the MAP_POPULATE flag on Linux. It has no effect on Windows.

Example

use rarena_allocator::MmapOptions;


let opts = MmapOptions::new().populate();

Trait Implementations

impl Clone for MmapOptions

fn clone(&self) -> MmapOptions

Returns a copy of the value.

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

Performs copy-assignment from source.

impl Debug for MmapOptions

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

Formats the value using the given formatter.

impl Default for MmapOptions

fn default() -> Self

Returns the “default value” for a type.

impl From<MmapOptions> for MmapOptions

fn from(opts: Mmap2Options) -> Self

Converts to this type from the input type.