diff --git a/storage/innobase/buf/buf0flu.cc b/storage/innobase/buf/buf0flu.cc
index f0ef7a43fc506..ca383f1720bea 100644
--- a/storage/innobase/buf/buf0flu.cc
+++ b/storage/innobase/buf/buf0flu.cc
@@ -93,6 +93,8 @@ class async_flush_lsn
   void try_clear_if_at_most(lsn_t threshold) noexcept
   {
     lsn_t snapshot= m_lsn.load();
+    if (!snapshot)
+      return; /* already cleared: avoid a redundant atomic CAS */
     if (threshold >= snapshot)
       m_lsn.compare_exchange_strong(snapshot, 0);
   }