Struct slabmalloc::ZoneAllocator

pub struct ZoneAllocator<'a> { /* private fields */ }

A zone allocator for arbitrary sized allocations.

Has a bunch of SCAllocator and through that can serve allocation requests for many different object sizes up to (MAX_SIZE_CLASSES) by selecting the right SCAllocator for allocation and deallocation.

The allocator provides to refill functions refill and refill_large to provide the underlying SCAllocator with more memory in case it runs out.

Implementations

impl<'a> ZoneAllocator<'a>

pub const MAX_ALLOC_SIZE: usize = 131_072usize

Maximum size that allocated within LargeObjectPages (2 MiB). This is also the maximum object size that this allocator can handle.

pub const MAX_BASE_ALLOC_SIZE: usize = 256usize

Maximum size which is allocated with ObjectPages (4 KiB pages).

e.g. this is 4 KiB - 80 bytes of meta-data.

pub const fn new() -> ZoneAllocator<'a>

pub fn get_max_size(current_size: usize) -> Option<usize>

Return maximum size an object of size current_size can use.

Used to optimize realloc.

pub fn try_reclaim_base_pages<F>(&mut self, to_reclaim: usize, dealloc: F) where
    F: Fn(*mut ObjectPage<'_>), 

Reclaims empty pages by calling dealloc on it and removing it from the empty lists in the SCAllocator.

The dealloc function is called at most reclaim_base_max times for base pages, and at most reclaim_large_max for large pages.

pub fn try_reclaim_large_pages<F>(&mut self, to_reclaim: usize, dealloc: F) where
    F: FnMut(*mut LargeObjectPage<'_>), 

Reclaims empty pages by calling dealloc on it and removing it from the empty lists in the SCAllocator.

The dealloc function is called at most reclaim_base_max times for base pages, and at most reclaim_large_max for large pages.

Trait Implementations

impl<'a> Allocator<'a> for ZoneAllocator<'a>

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

Allocate a pointer to a block of memory described by layout.

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

Deallocates a pointer to a block of memory, which was previously allocated by allocate.

Arguments

• ptr - Address of the memory location to free.
• layout - Memory layout of the block pointed to by ptr.

unsafe fn refill(
    &mut self,
    layout: Layout,
    new_page: &'a mut ObjectPage<'a>
) -> Result<(), AllocationError>

Refills the SCAllocator for a given Layout with an ObjectPage.

Safety

ObjectPage needs to be emtpy etc.

unsafe fn refill_large(
    &mut self,
    layout: Layout,
    new_page: &'a mut LargeObjectPage<'a>
) -> Result<(), AllocationError>

Refills the SCAllocator for a given Layout with an ObjectPage.

Safety

ObjectPage needs to be emtpy etc.

impl<'a> Default for ZoneAllocator<'a>

fn default() -> ZoneAllocator<'a>

Returns the “default value” for a type.