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reorder, get rid of TODO

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This commit is contained in:
Joonas Koivunen
2023-08-24 20:07:12 +03:00
parent ecf34bb3e4
commit d8cb81118a
1 changed files with 41 additions and 43 deletions
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84
pageserver/src/tenant/storage_layer.rs
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@@ -308,47 +308,6 @@ impl LayerAccessStats {
}
}
/// The download-ness ([`DownloadedLayer`]) can be either resident or wanted evicted.
///
/// However when we want something evicted, we cannot evict it right away as there might be current
/// reads happening on it. It has been for example searched from [`LayerMap`] but not yet
/// [`Layer::get_value_reconstruct_data`].
///
/// [`LayerMap`]: crate::tenant::layer_map::LayerMap
enum ResidentOrWantedEvicted {
Resident(Arc<DownloadedLayer>),
WantedEvicted(Weak<DownloadedLayer>),
}
impl ResidentOrWantedEvicted {
fn get(&self) -> Option<Arc<DownloadedLayer>> {
match self {
ResidentOrWantedEvicted::Resident(strong) => Some(strong.clone()),
ResidentOrWantedEvicted::WantedEvicted(weak) => weak.upgrade(),
}
}
/// When eviction is first requested, drop down to holding a [`Weak`].
///
/// Returns `true` if this was the first time eviction was requested.
fn downgrade(&mut self) -> &Weak<DownloadedLayer> {
let _was_first = match self {
ResidentOrWantedEvicted::Resident(strong) => {
let weak = Arc::downgrade(strong);
*self = ResidentOrWantedEvicted::WantedEvicted(weak);
// returning the weak is not useful, because the drop could had already ran with
// the replacement above, and that will take care of cleaning the Option we are in
true
}
ResidentOrWantedEvicted::WantedEvicted(_) => false,
};
match self {
ResidentOrWantedEvicted::WantedEvicted(ref weak) => weak,
_ => unreachable!("just wrote wanted evicted"),
}
}
}
/// A Layer contains all data in a "rectangle" consisting of a range of keys and
/// range of LSNs.
///
@@ -620,8 +579,47 @@ impl Layer {
}
}
// TODO:
// - internal arc, because I've now worked away majority of external wrapping
/// The download-ness ([`DownloadedLayer`]) can be either resident or wanted evicted.
///
/// However when we want something evicted, we cannot evict it right away as there might be current
/// reads happening on it. It has been for example searched from [`LayerMap`] but not yet
/// [`Layer::get_value_reconstruct_data`].
///
/// [`LayerMap`]: crate::tenant::layer_map::LayerMap
enum ResidentOrWantedEvicted {
Resident(Arc<DownloadedLayer>),
WantedEvicted(Weak<DownloadedLayer>),
}
impl ResidentOrWantedEvicted {
fn get(&self) -> Option<Arc<DownloadedLayer>> {
match self {
ResidentOrWantedEvicted::Resident(strong) => Some(strong.clone()),
ResidentOrWantedEvicted::WantedEvicted(weak) => weak.upgrade(),
}
}
/// When eviction is first requested, drop down to holding a [`Weak`].
///
/// Returns `true` if this was the first time eviction was requested.
fn downgrade(&mut self) -> &Weak<DownloadedLayer> {
let _was_first = match self {
ResidentOrWantedEvicted::Resident(strong) => {
let weak = Arc::downgrade(strong);
*self = ResidentOrWantedEvicted::WantedEvicted(weak);
// returning the weak is not useful, because the drop could had already ran with
// the replacement above, and that will take care of cleaning the Option we are in
true
}
ResidentOrWantedEvicted::WantedEvicted(_) => false,
};
match self {
ResidentOrWantedEvicted::WantedEvicted(ref weak) => weak,
_ => unreachable!("just wrote wanted evicted"),
}
}
}
struct LayerInner {
// only needed to check ondemand_download_behavior_treat_error_as_warn
conf: &'static PageServerConf,