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review suggestions: use Mutex, avoid reallocs in inner.last_access, custom Default impl

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This commit is contained in:
Christian Schwarz
2023-02-01 14:38:55 +01:00
parent 0ed5f2858b
commit ffa96d55c8
1 changed files with 22 additions and 7 deletions
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29
pageserver/src/tenant/storage_layer.rs
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@@ -19,7 +19,7 @@ use std::collections::VecDeque;
use std::ops::Range;
use std::path::PathBuf;
use std::sync::atomic::{self, AtomicBool};
use std::sync::{Arc, RwLock};
use std::sync::{Arc, Mutex};
use std::time::{SystemTime, UNIX_EPOCH};
use utils::{
@@ -89,7 +89,7 @@ pub enum ValueReconstructResult {
}
#[derive(Default)]
pub struct LayerAccessStats(RwLock<LayerAccessStatsInner>);
pub struct LayerAccessStats(Mutex<LayerAccessStatsInner>);
#[derive(Clone)]
struct LayerAccessStatFullDetails {
@@ -98,7 +98,6 @@ struct LayerAccessStatFullDetails {
access_kind: LayerAccessKind,
}
#[derive(Default)]
struct LayerAccessStatsInner {
first_access: Option<LayerAccessStatFullDetails>,
count_by_access_kind: EnumMap<LayerAccessKind, u64>,
@@ -132,12 +131,25 @@ impl LayerAccessStatFullDetails {
pub static LAYER_ACCESS_STATS_KILLSWITCH: AtomicBool = AtomicBool::new(false);
impl Default for LayerAccessStatsInner {
fn default() -> Self {
LayerAccessStatsInner {
first_access: None,
count_by_access_kind: EnumMap::default(),
task_kind_flag: EnumSet::default(),
last_accesses: VecDeque::with_capacity(LayerAccessStats::LAST_ACCESSES_MAX_LEN),
}
}
}
impl LayerAccessStats {
const LAST_ACCESSES_MAX_LEN: usize = 16;
fn record_access(&self, access_kind: LayerAccessKind, task_kind: TaskKind) {
if LAYER_ACCESS_STATS_KILLSWITCH.load(atomic::Ordering::SeqCst) {
return;
}
let mut inner = self.0.write().unwrap();
let mut inner = self.0.lock().unwrap();
let this_access = LayerAccessStatFullDetails {
when: SystemTime::now(),
task_kind,
@@ -148,11 +160,14 @@ impl LayerAccessStats {
.get_or_insert_with(|| this_access.clone());
inner.count_by_access_kind[access_kind] += 1;
inner.task_kind_flag |= task_kind;
// make room first to avoid reallocs
while inner.last_accesses.len() >= Self::LAST_ACCESSES_MAX_LEN {
inner.last_accesses.pop_back();
}
inner.last_accesses.push_front(this_access);
inner.last_accesses.truncate(10); // TODO make runtime-configurable
}
fn reset(&self, what: LayerAccessStatsReset) {
let mut inner = self.0.write().unwrap();
let mut inner = self.0.lock().unwrap();
match what {
LayerAccessStatsReset::JustTaskKindFlags => {
inner.task_kind_flag.clear();
@@ -163,7 +178,7 @@ impl LayerAccessStats {
}
}
fn to_api_model(&self) -> pageserver_api::models::LayerAccessStats {
let inner = self.0.read().unwrap();
let inner = self.0.lock().unwrap();
let LayerAccessStatsInner {
first_access,
count_by_access_kind,