kho_preserve_pages
int kho_preserve_pages(struct page *page, unsigned long nr_pages);
err = kho_preserve_pages(vm->pages[i], nr_contig_pages);
EXPORT_SYMBOL_GPL(kho_preserve_pages);
err = kho_preserve_pages(virt_to_page(chunk), 1);
err = kho_preserve_pages(page, nr_pages);
err = kho_preserve_pages(fdt_page, 1);