Trait slabmalloc::AllocablePage

pub trait AllocablePage {
    const SIZE: usize;
    const METADATA_SIZE: usize;
    const HEAP_ID_OFFSET: usize;

    // Required methods
    fn new(mp: MappedPages8k, heap_id: usize) -> Self
       where Self: Sized;
    fn retrieve_mapped_pages(&mut self) -> Option<MappedPages8k>;
    fn clear_metadata(&mut self);
    fn set_heap_id(&mut self, heap_id: usize);
    fn heap_id(&self) -> usize;
    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;
    fn buffer_size() -> usize;

    // 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<(), &'static str> { ... }
}

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:

• MappedPages8k object that owns this memory
• 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.

const METADATA_SIZE: usize

const HEAP_ID_OFFSET: usize

Required Methods

fn new(mp: MappedPages8k, heap_id: usize) -> Selfwhere Self: Sized,

fn retrieve_mapped_pages(&mut self) -> Option<MappedPages8k>

fn clear_metadata(&mut self)

fn set_heap_id(&mut self, heap_id: usize)

fn heap_id(&self) -> usize

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,

fn buffer_size() -> usize

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<(), &'static str>

Deallocates a memory object within this page.

Implementors

impl<'a> AllocablePage for ObjectPage8k<'a>

const SIZE: usize = 8_192usize

const METADATA_SIZE: usize = 128usize

const HEAP_ID_OFFSET: usize = 8_104usize