VM_MEMATTR_WRITE_BACK
pmap_page_set_memattr((struct vm_page *)pages[i], VM_MEMATTR_WRITE_BACK);
pmap_mapdev_attr(mapping->base, mapping->size, VM_MEMATTR_WRITE_BACK);
VM_MEMATTR_WRITE_BACK : ttm_io_prot(bo->mem.placement, 0));
mode = VM_MEMATTR_WRITE_BACK;
#define VM_MEMATTR_DEFAULT VM_MEMATTR_WRITE_BACK