chore: remove some excessive allocs in hot path (#13176)

crates/net/network/src/transactions/fetcher.rs

@@ -278,7 +278,6 @@ impl<N: NetworkPrimitives> TransactionFetcher<N> {
             + IntoIterator<Item = (TxHash, Option<(u8, usize)>)>,
     ) -> RequestTxHashes {
         let mut acc_size_response = 0;
-        let hashes_from_announcement_len = hashes_from_announcement.len();
 
         let mut hashes_from_announcement_iter = hashes_from_announcement.into_iter();
 
@@ -292,7 +291,7 @@ impl<N: NetworkPrimitives> TransactionFetcher<N> {
             acc_size_response = size;
         }
 
-        let mut surplus_hashes = RequestTxHashes::with_capacity(hashes_from_announcement_len - 1);
+        let mut surplus_hashes = RequestTxHashes::default();
 
         // folds size based on expected response size  and adds selected hashes to the request
         // list and the other hashes to the surplus list
@@ -326,8 +325,6 @@ impl<N: NetworkPrimitives> TransactionFetcher<N> {
         }
 
         surplus_hashes.extend(hashes_from_announcement_iter.map(|(hash, _metadata)| hash));
-        surplus_hashes.shrink_to_fit();
-        hashes_to_request.shrink_to_fit();
 
         surplus_hashes
     }
@@ -432,8 +429,7 @@ impl<N: NetworkPrimitives> TransactionFetcher<N> {
         peers: &HashMap<PeerId, PeerMetadata<N>>,
         has_capacity_wrt_pending_pool_imports: impl Fn(usize) -> bool,
     ) {
-        let init_capacity_req = approx_capacity_get_pooled_transactions_req_eth68(&self.info);
+        let mut hashes_to_request = RequestTxHashes::default();
-        let mut hashes_to_request = RequestTxHashes::with_capacity(init_capacity_req);
         let is_session_active = |peer_id: &PeerId| peers.contains_key(peer_id);
 
         let mut search_durations = TxFetcherSearchDurations::default();
@@ -482,9 +478,6 @@ impl<N: NetworkPrimitives> TransactionFetcher<N> {
             search_durations.fill_request
         );
 
-        // free unused memory
-        hashes_to_request.shrink_to_fit();
-
         self.update_pending_fetch_cache_search_metrics(search_durations);
 
         trace!(target: "net::tx",

crates/net/network/src/transactions/mod.rs

@@ -640,16 +640,8 @@ where
             return
         }
 
-        // load message version before announcement data type is destructed in packing
+        let mut hashes_to_request =
-        let msg_version = valid_announcement_data.msg_version();
+            RequestTxHashes::with_capacity(valid_announcement_data.len() / 4);
-        //
-        // demand recommended soft limit on response, however the peer may enforce an arbitrary
-        // limit on the response (2MB)
-        //
-        // request buffer is shrunk via call to pack request!
-        let init_capacity_req =
-            self.transaction_fetcher.approx_capacity_get_pooled_transactions_req(msg_version);
-        let mut hashes_to_request = RequestTxHashes::with_capacity(init_capacity_req);
         let surplus_hashes =
             self.transaction_fetcher.pack_request(&mut hashes_to_request, valid_announcement_data);
 
@@ -657,7 +649,6 @@ where
             trace!(target: "net::tx",
                 peer_id=format!("{peer_id:#}"),
                 surplus_hashes=?*surplus_hashes,
-                %msg_version,
                 %client,
                 "some hashes in announcement from peer didn't fit in `GetPooledTransactions` request, buffering surplus hashes"
             );
@@ -668,7 +659,6 @@ where
         trace!(target: "net::tx",
             peer_id=format!("{peer_id:#}"),
             hashes=?*hashes_to_request,
-            %msg_version,
             %client,
             "sending hashes in `GetPooledTransactions` request to peer's session"
         );