diff --git a/core/txpool/legacypool/list.go b/core/txpool/legacypool/list.go
index 2b3bde6384..72e86c6011 100644
--- a/core/txpool/legacypool/list.go
+++ b/core/txpool/legacypool/list.go
@@ -160,7 +160,7 @@ func (m *sortedMap) Cap(threshold int) types.Transactions {
 	// Otherwise gather and drop the highest nonce'd transactions
 	var drops types.Transactions
 
-	sort.Sort(*m.index)
+	sort.Sort(*m.index) // the sorted array is a heap, so no need to reheap after deleting tail items
 	for size := len(m.items); size > threshold; size-- {
 		drops = append(drops, m.items[(*m.index)[size-1]])
 		delete(m.items, (*m.index)[size-1])