add extrinsic length limit

runtime/common/src/fees.rs

@@ -61,8 +61,8 @@ where
     /// Function to convert weight to fee when "constant-fees" feature is not enabled.
     ///
     /// This function calculates the fee based on the length of the transaction in bytes.
-    /// If the current block weight and length are less than a fraction of the max block weight and length and the fee multiplier is one,
-    /// it returns a zero fee. Otherwise, it calculates the fee based on the length in bytes.
+    /// If the current block weight and length are less than a fraction of the max block weight and length, the fee multiplier is one,
+    /// and the extrinsic length is less than 256 bytes, no fees are applied. Otherwise, it calculates the fee based on the length in bytes.
     #[cfg(not(feature = "constant-fees"))]
     fn weight_to_fee(length_in_bytes: &Weight) -> Self::Balance {
         let weights = Runtime::BlockWeights::get();
@@ -76,16 +76,19 @@ where
         let length = Runtime::BlockLength::get();
         let normal_max_length = *length.max.get(DispatchClass::Normal) as u64;
         let current_block_length = <frame_system::Pallet<Runtime>>::all_extrinsics_len() as u64;
+        // One remark extrinsic overhead is approximately 110 bytes
+        let max_extrinsic_length = 256;
 
         if current_block_weight
             .get(DispatchClass::Normal)
             .all_lt(Target::get() * normal_max_weight)
             && current_block_length < (Target::get() * normal_max_length)
             && fee_multiplier.is_one()
+            && length_in_bytes.ref_time() < max_extrinsic_length
         {
             0u32.into()
         } else {
-            Self::Balance::saturated_from(length_in_bytes.ref_time() / 100u64)
+            Self::Balance::saturated_from(length_in_bytes.ref_time() / 10u64)
         }
     }