diff --git a/pageserver/src/feature_resolver.rs b/pageserver/src/feature_resolver.rs
index 6ce4522080..65cac8eea1 100644
--- a/pageserver/src/feature_resolver.rs
+++ b/pageserver/src/feature_resolver.rs
@@ -1,4 +1,8 @@
-use std::{collections::HashMap, sync::Arc, time::Duration};
+use std::{
+    collections::HashMap,
+    sync::{Arc, atomic::AtomicBool},
+    time::Duration,
+};
 
 use arc_swap::ArcSwap;
 use pageserver_api::config::NodeMetadata;
@@ -355,11 +359,17 @@ impl PerTenantProperties {
     }
 }
 
-#[derive(Clone)]
 pub struct TenantFeatureResolver {
     inner: FeatureResolver,
     tenant_id: TenantId,
-    cached_tenant_properties: Arc<ArcSwap<HashMap<String, PostHogFlagFilterPropertyValue>>>,
+    cached_tenant_properties: ArcSwap<HashMap<String, PostHogFlagFilterPropertyValue>>,
+
+    // Add feature flag on the critical path below.
+    //
+    // If a feature flag will be used on the critical path, we will update it in the tenant housekeeping loop insetad of
+    // resolving directly by calling `evaluate_multivariate` or `evaluate_boolean`. Remember to update the flag in the
+    // housekeeping loop. The user should directly read this atomic flag instead of using the set of evaluate functions.
+    pub feature_test_remote_size_flag: AtomicBool,
 }
 
 impl TenantFeatureResolver {
@@ -367,7 +377,8 @@ impl TenantFeatureResolver {
         Self {
             inner,
             tenant_id,
-            cached_tenant_properties: Arc::new(ArcSwap::new(Arc::new(HashMap::new()))),
+            cached_tenant_properties: ArcSwap::new(Arc::new(HashMap::new())),
+            feature_test_remote_size_flag: AtomicBool::new(false),
         }
     }
 
@@ -396,7 +407,8 @@ impl TenantFeatureResolver {
         self.inner.is_feature_flag_boolean(flag_key)
     }
 
-    pub fn update_cached_tenant_properties(&self, tenant_shard: &TenantShard) {
+    /// Refresh the cached properties and flags on the critical path.
+    pub fn refresh_properties_and_flags(&self, tenant_shard: &TenantShard) {
         let mut remote_size_mb = None;
         for timeline in tenant_shard.list_timelines() {
             let size = timeline.metrics.resident_physical_size_get();
@@ -410,5 +422,12 @@ impl TenantFeatureResolver {
         self.cached_tenant_properties.store(Arc::new(
             PerTenantProperties { remote_size_mb }.into_posthog_properties(),
         ));
+
+        // BEGIN: Update the feature flag on the critical path.
+        self.feature_test_remote_size_flag.store(
+            self.evaluate_boolean("test-remote-size-flag").is_ok(),
+            std::sync::atomic::Ordering::Relaxed,
+        );
+        // END: Update the feature flag on the critical path.
     }
 }
diff --git a/pageserver/src/tenant.rs b/pageserver/src/tenant.rs
index 49b92915da..96ed4672a6 100644
--- a/pageserver/src/tenant.rs
+++ b/pageserver/src/tenant.rs
@@ -388,7 +388,7 @@ pub struct TenantShard {
 
     l0_flush_global_state: L0FlushGlobalState,
 
-    pub(crate) feature_resolver: TenantFeatureResolver,
+    pub(crate) feature_resolver: Arc<TenantFeatureResolver>,
 }
 impl std::fmt::Debug for TenantShard {
     fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
@@ -3411,7 +3411,7 @@ impl TenantShard {
         }
 
         // Update the feature resolver with the latest tenant-spcific data.
-        self.feature_resolver.update_cached_tenant_properties(self);
+        self.feature_resolver.refresh_properties_and_flags(self);
     }
 
     pub fn timeline_has_no_attached_children(&self, timeline_id: TimelineId) -> bool {
@@ -4500,10 +4500,10 @@ impl TenantShard {
             gc_block: Default::default(),
             l0_flush_global_state,
             basebackup_cache,
-            feature_resolver: TenantFeatureResolver::new(
+            feature_resolver: Arc::new(TenantFeatureResolver::new(
                 feature_resolver,
                 tenant_shard_id.tenant_id,
-            ),
+            )),
         }
     }
 
diff --git a/pageserver/src/tenant/timeline.rs b/pageserver/src/tenant/timeline.rs
index 296b922599..44a4f1e911 100644
--- a/pageserver/src/tenant/timeline.rs
+++ b/pageserver/src/tenant/timeline.rs
@@ -201,7 +201,7 @@ pub struct TimelineResources {
     pub l0_compaction_trigger: Arc<Notify>,
     pub l0_flush_global_state: l0_flush::L0FlushGlobalState,
     pub basebackup_cache: Arc<BasebackupCache>,
-    pub feature_resolver: TenantFeatureResolver,
+    pub feature_resolver: Arc<TenantFeatureResolver>,
 }
 
 pub struct Timeline {
@@ -449,7 +449,7 @@ pub struct Timeline {
     /// A channel to send async requests to prepare a basebackup for the basebackup cache.
     basebackup_cache: Arc<BasebackupCache>,
 
-    feature_resolver: TenantFeatureResolver,
+    feature_resolver: Arc<TenantFeatureResolver>,
 }
 
 pub(crate) enum PreviousHeatmap {
@@ -3122,7 +3122,7 @@ impl Timeline {
 
                 basebackup_cache: resources.basebackup_cache,
 
-                feature_resolver: resources.feature_resolver,
+                feature_resolver: resources.feature_resolver.clone(),
             };
 
             result.repartition_threshold =