Enum PagePolicy 

pub enum PagePolicy {
    Resident,
    LazyRowGranular,
    OnDemand,
}

What the loader should do with a section’s pages.

This is the decision layer: a total, pure function of the access class, unit-testable with no syscalls and no unsafe. Applying it — mmap plus the matching madvise — belongs to the audited unsafe island in ftts-kernels, because ftts-artifacts is forbid(unsafe_code). Keeping the two apart means the policy can be argued about and tested here, where getting it wrong is cheap, rather than inside a syscall wrapper where it is not.

Variants

Resident

Fault in eagerly and keep resident: MADV_WILLNEED.

Only for sections read every frame. The microdecoder pack is the whole reason this variant exists — it is reread 15× per frame and its residency is the project’s #1 design center.

LazyRowGranular

Map lazily and let the kernel fault pages in as they are touched, a row at a time.

Never MADV_WILLNEED. The text embedding is ~622 MB of which one synthesis touches a few kilobytes; prefetching it wholesale would dominate startup and evict the very pages PagePolicy::Resident exists to protect.

OnDemand

Map lazily, no advice. Enrollment sections a synthesis run never touches.

Implementations

impl PagePolicy

pub const fn as_str(self) -> &'static str

The stable wire string, for ftts inspect and the loader’s trace events.

pub const fn may_prefetch(self) -> bool

Whether the loader may issue MADV_WILLNEED for this policy.

The single invariant the whole policy exists to enforce. Expressed as its own predicate so the syscall island can assert on it directly rather than re-deriving it from the class.

Trait Implementations

impl Clone for PagePolicy

fn clone(&self) -> PagePolicy

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for PagePolicy

impl Debug for PagePolicy

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

Formats the value using the given formatter.

impl Display for PagePolicy

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

Formats the value using the given formatter.

impl Eq for PagePolicy

impl Ord for PagePolicy

fn cmp(&self, other: &PagePolicy) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for PagePolicy

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for PagePolicy

fn partial_cmp(&self, other: &PagePolicy) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl StructuralPartialEq for PagePolicy