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wip: get rid of LayerE::evict

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This commit is contained in:
Joonas Koivunen
2023-08-21 09:44:05 +03:00
parent 1e33692c1c
commit 52eaa52573
1 changed files with 9 additions and 33 deletions
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42
pageserver/src/tenant/storage_layer.rs
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@@ -45,6 +45,7 @@ pub use layer_desc::{PersistentLayerDesc, PersistentLayerKey};
use self::delta_layer::DeltaEntry;
use super::remote_timeline_client::RemoteTimelineClient;
use super::Timeline;
use utils::sync::heavier_once_cell;
pub fn range_overlaps<T>(a: &Range<T>, b: &Range<T>) -> bool
where
@@ -542,42 +543,21 @@ impl LayerE {
})
}
/// Evict the the layer file as soon as possible, but then allow redownloads to happen.
pub(crate) async fn evict(
pub(crate) async fn evict_and_wait(
&self,
_: &RemoteTimelineClient,
) -> Result<bool, super::timeline::EvictionError> {
assert!(
self.have_remote_client,
"refusing to evict without a remote timeline client"
);
self.wanted_evicted.store(true, Ordering::Release);
let Some(guard) = self.inner.get() else {
// we don't need to wait around if there is a download ongoing, because that might reset the wanted_evicted
// however it's also possible that we are present and just accessed by someone else.
return Err(super::timeline::EvictionError::NotFound);
};
// now, this might immediatedly cause the drop fn to run, but that'll only act on
// background
Ok(
Self::get_or_apply_evictedness(Some(guard), &self.wanted_evicted)
.map(|_strong| false)
.unwrap_or(true),
)
}
pub(crate) async fn evict_and_wait(&self) -> Result<(), super::timeline::EvictionError> {
) -> Result<(), super::timeline::EvictionError> {
use tokio::sync::broadcast::error::RecvError;
assert!(self.have_remote_client);
self.wanted_evicted.store(true, Ordering::Release);
let mut rx = self.status.subscribe();
// why call get instead of looking at the watch? because get will downgrade any
// Arc<_> it finds, because we set the wanted_evicted
if dbg!(self.get()).is_none() {
if self.get().is_none() {
// it was not evictable in the first place
// our store to the wanted_evicted does not matter; it will be reset by next download
return Err(super::timeline::EvictionError::NotFound);
@@ -665,8 +645,6 @@ impl LayerE {
})
}
fn get_or_apply_evictedness(
guard: Option<heavier_once_cell::Guard<'_, ResidentOrWantedEvicted>>,
wanted_evicted: &AtomicBool,
@@ -753,7 +731,9 @@ impl LayerE {
// ))
//
// this check is only probablistic, seems like flakyness footgun
anyhow::bail!("refusing to download layer {self} due to RequestContext")
anyhow::bail!(
"refusing to download layer {self} due to RequestContext"
)
}
}
}
@@ -1267,10 +1247,6 @@ enum LayerKind {
Image(image_layer::ImageLayerInner),
}
mod heavier_once_cell {
pub(super) use utils::sync::heavier_once_cell::{Guard, OnceCell};
}
/// Supertrait of the [`Layer`] trait that captures the bare minimum interface
/// required by [`LayerMap`](super::layer_map::LayerMap).
///