pcpu_page_idx
__free_page(pages[pcpu_page_idx(cpu, i)]);
__free_page(pages[pcpu_page_idx(tcpu, i)]);
pages[pcpu_page_idx(cpu, i)] = page;
&pages[pcpu_page_idx(cpu, page_start)],
pcpu_set_page_chunk(pages[pcpu_page_idx(cpu, i)],
struct page *page = pages[pcpu_page_idx(cpu, i)];
struct page **pagep = &pages[pcpu_page_idx(cpu, i)];