diff --git a/module/zfs/spa_log_spacemap.c b/module/zfs/spa_log_spacemap.c
index c055c589c61b..317a074f919d 100644
--- a/module/zfs/spa_log_spacemap.c
+++ b/module/zfs/spa_log_spacemap.c
@@ -259,6 +259,11 @@ static ZFS_MODULE_ULONG zfs_unflushed_log_block_min = 1000;
  */
 static ZFS_MODULE_ULONG zfs_unflushed_log_block_max = (1ULL << 18);
 
+/*
+ * Also we have a hard limit in the size of the log in terms of dirty TXGs.
+ */
+static unsigned long zfs_unflushed_log_txg_max = 1000;
+
 /*
  * Max # of rows allowed for the log_summary. The tradeoff here is accuracy and
  * stability of the flushing algorithm (longer summary) vs its runtime overhead