diff --git a/tune-tikv-memory-performance.md b/tune-tikv-memory-performance.md
index acaa8c4946dbc..3fade7cac85d3 100644
--- a/tune-tikv-memory-performance.md
+++ b/tune-tikv-memory-performance.md
@@ -30,7 +30,7 @@ Each CF also has a separate `write buffer`. You can configure the size by settin
 
 ## Parameter specification
 
-```
+```toml
 # Log level: trace, debug, warn, error, info, off.
 log-level = "info"