Enum MmapHints 

pub enum MmapHints {
    Eager,
    Lazy,
}

Controls mmap prefault strategy for read_file_with_hints.

Different tools benefit from different page-fault strategies:

• Eager (default): POPULATE_READ prefaults all pages upfront, best when the entire file will be processed and startup latency is acceptable.
• Lazy: skips POPULATE_READ, lets pages fault on demand during SIMD scans. Best for tools like nl where memchr overlaps with lazy faults, avoiding the ~2ms upfront populate cost on 10MB files.

Both modes always apply HugePage (>= 2MB) and Sequential. WillNeed is applied for files in the 1-4MB range in both modes, and as a fallback for PopulateRead failure in Eager mode.

Variants

Eager

Prefault pages eagerly via POPULATE_READ (or WillNeed fallback).

Lazy

Let pages fault lazily during access. Still applies WillNeed for 1-4MB files where lazy faults won’t overlap with processing.

Trait Implementations

impl Clone for MmapHints

fn clone(&self) -> MmapHints

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for MmapHints

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

Formats the value using the given formatter.

impl PartialEq for MmapHints

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

Tests for self and other values to be equal, and is used by ==.

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

Tests for !=. The default implementation is almost always sufficient, and should not be overridden without very good reason.

impl Copy for MmapHints

impl Eq for MmapHints

impl StructuralPartialEq for MmapHints