Struct PageCacheMetrics 

pub struct PageCacheMetrics { /* private fields */ }

Page cache statistics.

Each thread has its own page cache, see crate::set_page_cache_size. The cache reports to the metrics that are current on its thread, see PageCacheMetrics::current. Statistics are updated with relaxed atomics, a snapshot is not a consistent cut across all fields.

Updates are a plain load and store, not an atomic read-modify-write, so metrics must be updated by one thread at a time. If the same metrics are installed on several threads with PageCacheMetrics::set_current, concurrent updates can be lost, counters undercount and the pages and bytes gauges drift permanently.

A page released on another thread goes to the cache of that thread, so allocations and releases of the same page can be reported to different metrics.

Implementations

impl PageCacheMetrics

pub fn new() -> Arc<Self>

Creates new metrics.

pub fn current() -> Arc<Self>

Returns the metrics of the current thread’s page cache.

Each thread has its own metrics, created with the cache, unless other metrics were installed with PageCacheMetrics::set_current.

pub fn set_current(metrics: Arc<Self>)

Installs metrics as the metrics of the current thread’s page cache.

The pages held by the cache are moved from the previous metrics to metrics. Metrics must not be current on more than one thread at a time, updates are not atomic read-modify-writes.

pub fn snapshot(&self) -> PageCacheSnapshot

Returns a snapshot of the statistics.

Trait Implementations

impl Debug for PageCacheMetrics

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

Formats the value using the given formatter.

impl Default for PageCacheMetrics

fn default() -> Self

Returns the “default value” for a type.