Struct mmtk::util::heap::blockpageresource::BlockQueue

struct BlockQueue<B: Region> {
    cursor: AtomicUsize,
    data: UnsafeCell<Box<[MaybeUninit<B>]>>,
}

A block list that supports fast lock-free push/pop operations

Fields

cursor: AtomicUsize

The number of elements in the queue.

data: UnsafeCell<Box<[MaybeUninit<B>]>>

The underlying data storage.

• UnsafeCell<T>: It may be accessed by multiple threads.
• Box<[T]>: It holds an array allocated on the heap. It cannot be resized, but can be replaced with another array as a whole.
• MaybeUninit<T>: It may contain uninitialized elements.

The implementaiton of BlockQueue must ensure there is no data race, and it never reads uninitialized elements.

Implementations

impl<B: Region> BlockQueue<B>

fn new() -> Self

Create an array

impl<B: Region> BlockQueue<B>

const CAPACITY: usize = 256usize

fn get_entry(&self, i: usize) -> B

Get an entry

unsafe fn set_entry(&self, i: usize, block: B)

Set an entry.

It’s unsafe unless the array is accessed by only one thread (i.e. used as a thread-local array).

unsafe fn push_relaxed(&self, block: B) -> Result<(), B>

Non-atomically push an element.

It’s unsafe unless the array is accessed by only one thread (i.e. used as a thread-local array).

fn pop(&self) -> Option<B>

Atomically pop an element from the array.

fn len(&self) -> usize

Get array size

fn is_empty(&self) -> bool

Test if the array is empty

fn iterate_blocks(&self, f: &mut impl FnMut(B))

Iterate all elements in the array

fn replace(&self, new_array: Self) -> Self

Replace the array with a new array.

Return the old array