Struct MemoryPolicy 

#[non_exhaustive]
pub struct MemoryPolicy {
    pub percent: u8,
    pub ceiling: usize,
    pub split: bool,
}

How a memory cache follows the machine: a share of the memory the user’s resident hosts could hold together, split between them.

Fields (Non-exhaustive)

Non-exhaustive structs could have additional fields added in future. Therefore, non-exhaustive structs cannot be constructed in external crates using the traditional Struct { .. } syntax; cannot be matched against without a wildcard ..; and struct update syntax will not work.

percent: u8

Share of (available memory + what the caches hold), in percent.

ceiling: usize

Most one process takes, in bytes.

split: bool

Split the share between the user’s registered processes.

Implementations

impl MemoryPolicy

pub const PERCENT: u8 = 25

Default share of the available memory.

pub const FLOOR: usize

Least one process takes: below this the LRU would thrash on every query (it always keeps at least one entry anyway).

pub const CEILING_MIN: usize

Bounds of the automatic ceiling (MemoryPolicy::auto_ceiling).

pub const CEILING_MAX: usize

Upper bound of the automatic ceiling, in bytes.

pub fn for_device(device: &Device) -> MemoryPolicy

The default policy for device.

pub fn auto_ceiling(total_memory: Option<u64>) -> usize

A sixteenth of physical memory, within MemoryPolicy::CEILING_MIN..=MemoryPolicy::CEILING_MAX: 2 GiB up to 32 GB of memory (where a quarter of the available memory is the tighter bound anyway), 6 GiB on a 96 GB machine. One server then keeps a phone’s worth of hot DEX on a large machine, while sixteen still split a quarter of it.

pub fn alone(&self, available: Option<u64>) -> usize

The budget of a process alone with available bytes free.

pub fn share( &self, available: Option<u64>, held_here: u64, others: &[ProcessUsage], ) -> usize

This process’s share: MemoryPolicy::percent of what the user’s registered processes could hold together (the available memory plus what their caches hold already), split evenly when MemoryPolicy::split, within MemoryPolicy::FLOOR..=ceiling. The ceiling when the available memory is unknown.

Trait Implementations

impl Clone for MemoryPolicy

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for MemoryPolicy

impl Debug for MemoryPolicy

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

Formats the value using the given formatter.

impl Default for MemoryPolicy

fn default() -> MemoryPolicy

Returns the “default value” for a type.

impl Eq for MemoryPolicy

impl PartialEq for MemoryPolicy

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

Equality operator ==.

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

Inequality operator !=.

impl StructuralPartialEq for MemoryPolicy