Struct Vmalloc

pub struct Vmalloc;

The virtually contiguous kernel allocator.

Vmalloc allocates pages from the page level allocator and maps them into the contiguous kernel virtual space. It is typically used for large allocations. The memory allocated with this allocator is not physically contiguous.

For more details see self.

Implementations

impl Vmalloc

pub unsafe fn to_page<'a>(ptr: NonNull<u8>) -> BorrowedPage<'a>

Convert a pointer to a Vmalloc allocation to a page::BorrowedPage.

Examples

use kernel::alloc::allocator::Vmalloc;

let mut vbox = VBox::<[u8; page::PAGE_SIZE]>::new_uninit(GFP_KERNEL)?;

{
    // SAFETY: By the type invariant of `Box` the inner pointer of `vbox` is non-null.
    let ptr = unsafe { NonNull::new_unchecked(from_mut(&mut *vbox)) };

    // SAFETY:
    // `ptr` is a valid pointer to a `Vmalloc` allocation.
    // `ptr` is valid for the entire lifetime of `page`.
    let page = unsafe { Vmalloc::to_page(ptr.cast()) };

    // SAFETY: There is no concurrent read or write to the same page.
    unsafe { page.fill_zero_raw(0, page::PAGE_SIZE)? };
}

Safety

• ptr must be a valid pointer to a Vmalloc allocation.
• ptr must remain valid for the entire duration of 'a.

Trait Implementations

impl Allocator for Vmalloc

const MIN_ALIGN: usize = 4_096usize

The minimum alignment satisfied by all allocations from this allocator.

unsafe fn realloc( ptr: Option<NonNull<u8>>, layout: Layout, old_layout: Layout, flags: Flags, nid: NumaNode, ) -> Result<NonNull<[u8]>, AllocError>

Re-allocate an existing memory allocation to satisfy the requested layout and a specific NUMA node request to allocate the memory for.

fn alloc( layout: Layout, flags: Flags, nid: NumaNode, ) -> Result<NonNull<[u8]>, AllocError>

Allocate memory based on layout, flags and nid.

unsafe fn free(ptr: NonNull<u8>, layout: Layout)

Free an existing memory allocation.