+/**
+ * vmballoon_split_refused_pages() - Split the 2MB refused pages to 4k.
+ *
+ * If inflation of 2MB pages was denied by the hypervisor, it is likely to be
+ * due to one or few 4KB pages. These 2MB pages may keep being allocated and
+ * then being refused. To prevent this case, this function splits the refused
+ * pages into 4KB pages and adds them into @prealloc_pages list.
+ *
+ * @ctl: pointer for the %struct vmballoon_ctl, which defines the operation.
+ */
+static void vmballoon_split_refused_pages(struct vmballoon_ctl *ctl)
+{
+ struct page *page, *tmp;
+ unsigned int i, order;
+
+ order = vmballoon_page_order(ctl->page_size);
+
+ list_for_each_entry_safe(page, tmp, &ctl->refused_pages, lru) {
+ list_del(&page->lru);
+ split_page(page, order);
+ for (i = 0; i < (1 << order); i++)
+ list_add(&page[i].lru, &ctl->prealloc_pages);
+ }
+ ctl->n_refused_pages = 0;
+}
+