31fafb678f
dynamically re-coloring pages; as machine-dependent code discovers the size of the system's caches, it may call uvm_page_recolor() with the new number of colors to use. If the new mumber of colors is smaller (or equal to) the current number of colors, then uvm_page_recolor() is a no-op. The system defaults to one bucket if machine-dependent code does not initialize uvmexp.ncolors before uvm_page_init() is called. Note that the number of color bins should be initialized to something reasonable as early as possible -- for many early memory allocations, we live with the consequences of the page choice for the lifetime of the boot.