Fix fixed map to allocate full size

Previously we always allocated just one slot.
aws · Oct 1, 2024 · 09436e2 · 09436e2
1 parent 81f1cd8
commit 09436e2
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Showing 3 changed files with 14 additions and 2 deletions.
diff --git a/dc/s2n-quic-dc/src/fixed_map.rs b/dc/s2n-quic-dc/src/fixed_map.rs
@@ -25,8 +25,9 @@ where
     S: BuildHasher,
 {
     pub fn with_capacity(entries: usize, hasher: S) -> Self {
+        let slots = std::cmp::max(1, (entries + SLOT_CAPACITY) / SLOT_CAPACITY).next_power_of_two();
         let map = Map {
-            slots: (0..std::cmp::min(1, (entries + SLOT_CAPACITY) / SLOT_CAPACITY))
+            slots: (0..slots)
                 .map(|_| Slot::new())
                 .collect::<Vec<_>>()
                 .into_boxed_slice(),

diff --git a/dc/s2n-quic-dc/src/fixed_map/test.rs b/dc/s2n-quic-dc/src/fixed_map/test.rs
@@ -31,3 +31,12 @@ fn slot_clear() {
 
     assert_eq!(slot.len(), 0);
 }
+
+#[test]
+fn capacity_size() {
+    let map: Map<u32, ()> = Map::with_capacity(500_000, Default::default());
+    for idx in 0..500_000 {
+        map.insert(idx, ());
+    }
+    assert!(map.len() >= 400_000, "{}", map.len());
+}
diff --git a/dc/s2n-quic-dc/src/path/secret/map/test.rs b/dc/s2n-quic-dc/src/path/secret/map/test.rs
@@ -317,7 +317,9 @@ fn check_invariants_no_overflow() {
 fn no_memory_growth() {
     let signer = stateless_reset::Signer::new(b"secret");
     let map = Map::new(signer);
-    for idx in 0..500_000_000 {
+    map.state.cleaner.stop();
+    for idx in 0..500_000 {
+        // FIXME: this ends up 2**16 peers in the `peers` map
         map.insert(fake_entry(idx as u16));
     }
 }