snapshot_page
struct page *snapshot_page;
snapshot_page = alloc_page(GFP_ATOMIC | __GFP_ZERO);
if (!snapshot_page) {
cpu_hw_evt->snapshot_addr = page_to_virt(snapshot_page);
cpu_hw_evt->snapshot_addr_phys = page_to_phys(snapshot_page);
snapshot_page(&ps, page);
snapshot_page(&ps, page);
void snapshot_page(struct page_snapshot *ps, const struct page *page);
snapshot_page(&ps, page);