Some have seen two wills of God in this verse: 1) A determinative will; namely, what God sovereignly determines what will happen and 2) A desirous will; namely, what God wishes or wants to happen.
For example, God wants (desirous will) all men to be saved and come to a knowledge of the truth, but God's sovereignly determines (determinative will) that only a few be saved.
Here is what Piper notes at the end of his book, The Pleasures of God:
"My aim in this appendix has simply been to show that God's will for all people to be saved is NOT at odds with the sovereignty of God's grace in election. There are "two wills in God" when it comes to salvation. They do NOT contradict. They are ordered according to God's infinite wisdom and one holds sway over the other when it is fitting in God's unfathomable mind. Thus, I have tried to give extensive biblical support for the statement of I.Howard Marshall: 'We must certainly distinguish between what God would like to see happen and what he actually does will to happen, and both of these things can be spoken of as God's will" (339).
"My answer to the question about what restrains God's will to save all people is this: It is God's supreme commitment to uphold and display the full range of his glory through the sovereign demonstration all his perfections, including his wrath and mercy, for the enjoyment of his chosen and believing people from every tribe and tongue and people and nation. This everlasting and ever-increasing joy of God's people in all of God's perfections is the shining forth of God's glory, which was his main aim in creation and redemption. God's delight in being God is the ground of our joy and God's glory" (339).