pageserver: don't pass config to PageHandler (#11973)

## Problem

The gRPC page service API will require decoupling the `PageHandler` from
the libpq protocol implementation. As preparation for this, avoid
passing in the entire server config to `PageHandler`, and instead
explicitly pass in the relevant fields.

Touches https://github.com/neondatabase/neon/issues/11728.

## Summary of changes

* Change `PageHandler` to take a `GetVectoredConcurrentIo` instead of
the entire config.
* Change `IoConcurrency::spawn_from_conf` to take a
`GetVectoredConcurrentIo`.

libs/pageserver_api/src/config.rs

@@ -235,7 +235,7 @@ pub enum PageServiceProtocolPipelinedBatchingStrategy {
     ScatteredLsn,
 }
 
-#[derive(Debug, Clone, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
+#[derive(Debug, Clone, Copy, PartialEq, Eq, serde::Serialize, serde::Deserialize)]
 #[serde(tag = "mode", rename_all = "kebab-case")]
 pub enum GetVectoredConcurrentIo {
     /// The read path is fully sequential: layers are visited

pageserver/src/basebackup.rs

@@ -144,7 +144,7 @@ where
         replica,
         ctx,
         io_concurrency: IoConcurrency::spawn_from_conf(
-            timeline.conf,
+            timeline.conf.get_vectored_concurrent_io,
             timeline
                 .gate
                 .enter()

pageserver/src/http/routes.rs

@@ -3199,7 +3199,7 @@ async fn list_aux_files(
             .await?;
 
     let io_concurrency = IoConcurrency::spawn_from_conf(
-        state.conf,
+        state.conf.get_vectored_concurrent_io,
         timeline.gate.enter().map_err(|_| ApiError::Cancelled)?,
     );
 

pageserver/src/page_service.rs

@@ -18,7 +18,7 @@ use itertools::Itertools;
 use jsonwebtoken::TokenData;
 use once_cell::sync::OnceCell;
 use pageserver_api::config::{
-    PageServicePipeliningConfig, PageServicePipeliningConfigPipelined,
+    GetVectoredConcurrentIo, PageServicePipeliningConfig, PageServicePipeliningConfigPipelined,
     PageServiceProtocolPipelinedBatchingStrategy, PageServiceProtocolPipelinedExecutionStrategy,
 };
 use pageserver_api::key::rel_block_to_key;
@@ -331,10 +331,10 @@ async fn page_service_conn_main(
     // But it's in a shared crate, so, we store connection_ctx inside PageServerHandler
     // and create the per-query context in process_query ourselves.
     let mut conn_handler = PageServerHandler::new(
-        conf,
         tenant_manager,
         auth,
         pipelining_config,
+        conf.get_vectored_concurrent_io,
         perf_span_fields,
         connection_ctx,
         cancel.clone(),
@@ -371,7 +371,6 @@ async fn page_service_conn_main(
 }
 
 struct PageServerHandler {
-    conf: &'static PageServerConf,
     auth: Option<Arc<SwappableJwtAuth>>,
     claims: Option<Claims>,
 
@@ -389,6 +388,7 @@ struct PageServerHandler {
     timeline_handles: Option<TimelineHandles>,
 
     pipelining_config: PageServicePipeliningConfig,
+    get_vectored_concurrent_io: GetVectoredConcurrentIo,
 
     gate_guard: GateGuard,
 }
@@ -844,17 +844,16 @@ impl BatchedFeMessage {
 impl PageServerHandler {
     #[allow(clippy::too_many_arguments)]
     pub fn new(
-        conf: &'static PageServerConf,
         tenant_manager: Arc<TenantManager>,
         auth: Option<Arc<SwappableJwtAuth>>,
         pipelining_config: PageServicePipeliningConfig,
+        get_vectored_concurrent_io: GetVectoredConcurrentIo,
         perf_span_fields: ConnectionPerfSpanFields,
         connection_ctx: RequestContext,
         cancel: CancellationToken,
         gate_guard: GateGuard,
     ) -> Self {
         PageServerHandler {
-            conf,
             auth,
             claims: None,
             connection_ctx,
@@ -862,6 +861,7 @@ impl PageServerHandler {
             timeline_handles: Some(TimelineHandles::new(tenant_manager)),
             cancel,
             pipelining_config,
+            get_vectored_concurrent_io,
             gate_guard,
         }
     }
@@ -1623,7 +1623,7 @@ impl PageServerHandler {
         }
 
         let io_concurrency = IoConcurrency::spawn_from_conf(
-            self.conf,
+            self.get_vectored_concurrent_io,
             match self.gate_guard.try_clone() {
                 Ok(guard) => guard,
                 Err(_) => {

pageserver/src/pgdatadir_mapping.rs

@@ -586,7 +586,7 @@ impl Timeline {
         // scan directory listing (new), merge with the old results
         let key_range = rel_tag_sparse_key_range(spcnode, dbnode);
         let io_concurrency = IoConcurrency::spawn_from_conf(
-            self.conf,
+            self.conf.get_vectored_concurrent_io,
             self.gate
                 .enter()
                 .map_err(|_| PageReconstructError::Cancelled)?,
@@ -645,7 +645,7 @@ impl Timeline {
         );
 
         let io_concurrency = IoConcurrency::spawn_from_conf(
-            self.conf,
+            self.conf.get_vectored_concurrent_io,
             self.gate
                 .enter()
                 .map_err(|_| PageReconstructError::Cancelled)?,
@@ -885,7 +885,7 @@ impl Timeline {
             );
 
             let io_concurrency = IoConcurrency::spawn_from_conf(
-                self.conf,
+                self.conf.get_vectored_concurrent_io,
                 self.gate
                     .enter()
                     .map_err(|_| PageReconstructError::Cancelled)?,

pageserver/src/tenant.rs

@@ -8596,8 +8596,10 @@ mod tests {
         lsn: Lsn,
         ctx: &RequestContext,
     ) -> Result<Option<Bytes>, GetVectoredError> {
-        let io_concurrency =
-            IoConcurrency::spawn_from_conf(tline.conf, tline.gate.enter().unwrap());
+        let io_concurrency = IoConcurrency::spawn_from_conf(
+            tline.conf.get_vectored_concurrent_io,
+            tline.gate.enter().unwrap(),
+        );
         let mut reconstruct_state = ValuesReconstructState::new(io_concurrency);
         let query = VersionedKeySpaceQuery::uniform(KeySpace::single(key..key.next()), lsn);
         let mut res = tline

pageserver/src/tenant/storage_layer.rs

@@ -31,6 +31,7 @@ pub use inmemory_layer::InMemoryLayer;
 pub(crate) use layer::{EvictionError, Layer, ResidentLayer};
 pub use layer_desc::{PersistentLayerDesc, PersistentLayerKey};
 pub use layer_name::{DeltaLayerName, ImageLayerName, LayerName};
+use pageserver_api::config::GetVectoredConcurrentIo;
 use pageserver_api::key::Key;
 use pageserver_api::keyspace::{KeySpace, KeySpaceRandomAccum};
 use pageserver_api::record::NeonWalRecord;
@@ -43,7 +44,6 @@ use self::inmemory_layer::InMemoryLayerFileId;
 use super::PageReconstructError;
 use super::layer_map::InMemoryLayerDesc;
 use super::timeline::{GetVectoredError, ReadPath};
-use crate::config::PageServerConf;
 use crate::context::{
     AccessStatsBehavior, PerfInstrumentFutureExt, RequestContext, RequestContextBuilder,
 };
@@ -318,11 +318,10 @@ impl IoConcurrency {
     }
 
     pub(crate) fn spawn_from_conf(
-        conf: &'static PageServerConf,
+        conf: GetVectoredConcurrentIo,
         gate_guard: GateGuard,
     ) -> IoConcurrency {
-        use pageserver_api::config::GetVectoredConcurrentIo;
-        let selected = match conf.get_vectored_concurrent_io {
+        let selected = match conf {
             GetVectoredConcurrentIo::Sequential => SelectedIoConcurrency::Sequential,
             GetVectoredConcurrentIo::SidecarTask => SelectedIoConcurrency::SidecarTask(gate_guard),
         };

pageserver/src/tenant/timeline.rs

@@ -3530,7 +3530,7 @@ impl Timeline {
                 };
 
                 let io_concurrency = IoConcurrency::spawn_from_conf(
-                    self_ref.conf,
+                    self_ref.conf.get_vectored_concurrent_io,
                     self_ref
                         .gate
                         .enter()
@@ -5559,7 +5559,7 @@ impl Timeline {
             });
 
             let io_concurrency = IoConcurrency::spawn_from_conf(
-                self.conf,
+                self.conf.get_vectored_concurrent_io,
                 self.gate
                     .enter()
                     .map_err(|_| CreateImageLayersError::Cancelled)?,

pageserver/src/tenant/timeline/detach_ancestor.rs

@@ -188,7 +188,7 @@ pub(crate) async fn generate_tombstone_image_layer(
         "removing non-inherited keys by writing an image layer with tombstones at the detach LSN"
     );
     let io_concurrency = IoConcurrency::spawn_from_conf(
-        detached.conf,
+        detached.conf.get_vectored_concurrent_io,
         detached.gate.enter().map_err(|_| Error::ShuttingDown)?,
     );
     let mut reconstruct_state = ValuesReconstructState::new(io_concurrency);