/* * uvm_map_reserve: reserve space in a vm_map for future use. * * => we reserve space in a map by putting a dummy map entry in the * map (dummy means obj=NULL, amap=NULL, prot=VM_PROT_NONE) * => map should be unlocked (we will write lock it) * => we return true if we were able to reserve space * => XXXCDC: should be inline? */