Trait AllocablePage 

pub trait AllocablePage {
    const SIZE: usize;

    // Required methods
    fn bitfield(&self) -> &[AtomicU64; 8];
    fn bitfield_mut(&mut self) -> &mut [AtomicU64; 8];
    fn prev(&mut self) -> &mut Rawlink<Self>
       where Self: Sized;
    fn next(&mut self) -> &mut Rawlink<Self>
       where Self: Sized;

    // Provided methods
    fn first_fit(&self, layout: Layout) -> Option<(usize, usize)> { ... }
    fn allocate(&mut self, layout: Layout) -> *mut u8 { ... }
    fn is_full(&self) -> bool { ... }
    fn is_empty(&self, relevant_bits: usize) -> bool { ... }
    fn deallocate(
        &self,
        ptr: NonNull<u8>,
        layout: Layout,
    ) -> Result<(), AllocationError> { ... }
}

This trait is used to define a page from which objects are allocated in an SCAllocator.

The implementor of this trait needs to provide access to the page meta-data, which consists of:

• A bitfield (to track allocations),
• prev and next pointers to insert the page in free lists

Required Associated Constants

const SIZE: usize

The total size (in bytes) of the page.

Note

We also assume that the address of the page will be aligned to SIZE.

Required Methods

fn bitfield(&self) -> &[AtomicU64; 8]

fn bitfield_mut(&mut self) -> &mut [AtomicU64; 8]

fn prev(&mut self) -> &mut Rawlink<Self>

where Self: Sized,

fn next(&mut self) -> &mut Rawlink<Self>

where Self: Sized,

Provided Methods

fn first_fit(&self, layout: Layout) -> Option<(usize, usize)>

Tries to find a free block within data that satisfies alignment requirement.

fn allocate(&mut self, layout: Layout) -> *mut u8

Tries to allocate an object within this page.

In case the slab is full, returns a null ptr.

fn is_full(&self) -> bool

Checks if we can still allocate more objects of a given layout within the page.

fn is_empty(&self, relevant_bits: usize) -> bool

Checks if the page has currently no allocations.

fn deallocate( &self, ptr: NonNull<u8>, layout: Layout, ) -> Result<(), AllocationError>

Deallocates a memory object within this page.

Dyn Compatibility

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors

impl<'a> AllocablePage for LargeObjectPage<'a>

const SIZE: usize = 2_097_152usize

impl<'a> AllocablePage for ObjectPage<'a>

const SIZE: usize = 4_096usize