Enum Migratetype 

#[repr(u8)]
pub enum Migratetype {
    Unmovable = 0,
    Movable = 1,
}

Minimal free-block classes used by the buddy allocator.

This is intentionally smaller than Linux’s full migratetype/pageblock matrix. The current design separates long-lived kernel pages from more reclaimable or relocatable user pages without introducing full migration machinery yet.

Variants

Unmovable = 0

Default class for kernel data, page tables and other pinned pages.

Movable = 1

Preferred class for user-space data and frames that can later be moved.

Implementations

impl Migratetype

pub const COUNT: usize = 2

Number of migratetypes tracked by the allocator.

pub const ALL: [Self; 2]

Stable iteration order used by diagnostics.

pub const fn index(self) -> usize

Returns the free-list index for this migratetype.

pub const fn fallback_order(self) -> [Self; 2]

Returns the donor probing order for an allocation request.

Bidirectional fallback is intentional: when the preferred migratetype list is empty, the allocator can borrow from the other class. This prevents allocation failures when one class is exhausted while the other has free pages. The trade-off is potential cross-class fragmentation, but this is acceptable for the current 2-class design.

Trait Implementations

impl Clone for Migratetype

fn clone(&self) -> Migratetype

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Migratetype

impl Debug for Migratetype

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for Migratetype

impl PartialEq for Migratetype

fn eq(&self, other: &Migratetype) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Migratetype