Struct buddy_system_allocator::LockedHeapWithRescue

pub struct LockedHeapWithRescue<const ORDER: usize> { /* private fields */ }

A locked version of Heap with rescue before oom

Usage

Create a locked heap:

use buddy_system_allocator::*;
let heap = LockedHeapWithRescue::new(|heap: &mut Heap<32>, layout: &core::alloc::Layout| {});

Before oom, the allocator will try to call rescue function and try for one more time.

Implementations

impl<const ORDER: usize> LockedHeapWithRescue<ORDER>

pub fn new(rescue: fn(_: &mut Heap<ORDER>, _: &Layout)) -> Self

Creates an empty heap

Methods from Deref<Target = Mutex<Heap<ORDER>>>

pub fn is_locked(&self) -> bool

Returns true if the lock is currently held.

Safety

This function provides no synchronization guarantees and so its result should be considered ‘out of date’ the instant it is called. Do not use it for synchronization purposes. However, it may be useful as a heuristic.

pub fn lock(&self) -> MutexGuard<'_, T>

Locks the [Mutex] and returns a guard that permits access to the inner data.

The returned value may be dereferenced for data access and the lock will be dropped when the guard falls out of scope.

let lock = spin::Mutex::new(0);
{
    let mut data = lock.lock();
    // The lock is now locked and the data can be accessed
    *data += 1;
    // The lock is implicitly dropped at the end of the scope
}

pub unsafe fn force_unlock(&self)

Force unlock this [Mutex].

Safety

This is extremely unsafe if the lock is not held by the current thread. However, this can be useful in some instances for exposing the lock to FFI that doesn’t know how to deal with RAII.

pub fn try_lock(&self) -> Option<MutexGuard<'_, T>>

Try to lock this [Mutex], returning a lock guard if successful.

Example

let lock = spin::Mutex::new(42);

let maybe_guard = lock.try_lock();
assert!(maybe_guard.is_some());

// `maybe_guard` is still held, so the second call fails
let maybe_guard2 = lock.try_lock();
assert!(maybe_guard2.is_none());

Trait Implementations

impl<const ORDER: usize> Deref for LockedHeapWithRescue<ORDER>

type Target = Mutex<Heap<ORDER>>

The resulting type after dereferencing.

fn deref(&self) -> &Self::Target

Dereferences the value.

impl<const ORDER: usize> GlobalAlloc for LockedHeapWithRescue<ORDER>

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

Allocate memory as described by the given layout.

unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout)

Deallocate the block of memory at the given ptr pointer with the given layout.

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

Behaves like alloc, but also ensures that the contents are set to zero before being returned.

unsafe fn realloc(
    &self,
    ptr: *mut u8,
    layout: Layout,
    new_size: usize
) -> *mut u8

Shrink or grow a block of memory to the given new_size. The block is described by the given ptr pointer and layout.