Mushroom Garlic Butter Sauce

6 tablespoons butter
10 cloves garlic, minced
6 cups fresh mushrooms, sliced
1 teaspoon dried marjoram
1/4 teaspoon salt
pepper to taste
2 tablespoons olive oil
2 tablespoons fresh parsley, chopped
1 lb linguine or fettuccine, cooked
Parmesan cheese, grated