Struct JitAllocatorOptions

pub struct JitAllocatorOptions {
    pub use_dual_mapping: bool,
    pub use_multiple_pools: bool,
    pub fill_unused_memory: bool,
    pub immediate_release: bool,
    pub custom_fill_pattern: Option<u32>,
    pub block_size: u32,
    pub granularity: u32,
}

Fields

use_dual_mapping: bool

Enables the use of an anonymous memory-mapped memory that is mapped into two buffers having a different pointer. The first buffer has read and execute permissions and the second buffer has read+write permissions.

See alloc_dual_mapping for more details about this feature.

Remarks

Dual mapping would be automatically turned on by JitAllocator in case of hardened runtime that enforces W^X policy, so specifying this flag is essentually forcing to use dual mapped pages even when RWX pages can be allocated and dual mapping is not necessary.

use_multiple_pools: bool

Enables the use of multiple pools with increasing granularity instead of a single pool. This flag would enable 3 internal pools in total having 64, 128, and 256 bytes granularity.

This feature is only recommended for users that generate a lot of code and would like to minimize the overhead of JitAllocator itself by having blocks of different allocation granularities. Using this feature only for few allocations won’t pay off as the allocator may need to create more blocks initially before it can take the advantage of variable block granularity.

fill_unused_memory: bool

Always fill reserved memory by a fill-pattern.

Causes a new block to be cleared by the fill pattern and freshly released memory to be cleared before making it ready for another use.

immediate_release: bool

When this flag is set the allocator would immediately release unused blocks during release() or reset(). When this flag is not set the allocator would keep one empty block in each pool to prevent excessive virtual memory allocations and deallocations in border cases, which involve constantly allocating and deallocating a single block caused by repetitive calling alloc() and release() when the allocator has either no blocks or have all blocks fully occupied.

custom_fill_pattern: Option<u32>

block_size: u32

granularity: u32

Trait Implementations

impl Clone for JitAllocatorOptions

fn clone(&self) -> JitAllocatorOptions

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for JitAllocatorOptions

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

Formats the value using the given formatter.

impl Default for JitAllocatorOptions

fn default() -> Self

Returns the “default value” for a type.

impl PartialEq for JitAllocatorOptions

fn eq(&self, other: &JitAllocatorOptions) -> bool

Tests for self and other values to be equal, and is used by ==.

const fn ne(&self, other: &Rhs) -> bool

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for JitAllocatorOptions

impl Eq for JitAllocatorOptions

impl StructuralPartialEq for JitAllocatorOptions