In 2 Samuel 21, What stopped God's three-year famine?

Hanging seven of Saul's sons and grandsons before the Lord.

Fewer Words Version: There was a famine in David's kingdom for three years. When David asked God why, God said, "It’s because Saul slew the Gibeonites."

So David asked the Gibeonites, "What can I do for you to make atonement?"

So David gave two of Saul's sons and five of his grandsons to the Gibeonites. And the Gibeonites hanged them on the hill before the Lord.

After that God stopped starving people with the famine. 2 Samuel 21:1-12