linux-master/mm/balloon_compaction.c

15 				     struct page *page)
18 	 * Block others from accessing the 'page' when we get around to
20 	 * holding a reference to the 'page' at this point. If we are not, then
23 	BUG_ON(!trylock_page(page));
24 	balloon_page_insert(b_dev_info, page);
25 	unlock_page(page);
30  * balloon_page_list_enqueue() - inserts a list of pages into the balloon page
32  * @b_dev_info: balloon device descriptor where we will insert a new page to
43 	struct page *page, *tmp;
48 	list_for_each_entry_safe(page, tmp, pages, lru) {
49 		list_del(&page->lru);
50 		balloon_page_enqueue_one(b_dev_info, page);
59  * balloon_page_list_dequeue() - removes pages from balloon's page list and
61  * @b_dev_info: balloon device descriptor where we will grab a page from.
71  * isn't empty - since the page list can be temporarily empty due to compaction
79 	struct page *page, *tmp;
84 	list_for_each_entry_safe(page, tmp, &b_dev_info->pages, lru) {
89 		 * Block others from accessing the 'page' while we get around to
90 		 * establishing additional references and preparing the 'page'
93 		if (!trylock_page(page))
97 		    PageIsolated(page)) {
99 			unlock_page(page);
102 		balloon_page_delete(page);
104 		list_add(&page->lru, pages);
105 		unlock_page(page);
115  * balloon_page_alloc - allocates a new page for insertion into the balloon
116  *			page list.
118  * Driver must call this function to properly allocate a new balloon page.
119  * Driver must call balloon_page_enqueue before definitively removing the page
122  * Return: struct page for the allocated page or NULL on allocation failure.
124 struct page *balloon_page_alloc(void)
126 	struct page *page = alloc_page(balloon_mapping_gfp_mask() |
129 	return page;
134  * balloon_page_enqueue - inserts a new page into the balloon page list.
136  * @b_dev_info: balloon device descriptor where we will insert a new page
137  * @page: new page to enqueue - allocated using balloon_page_alloc.
140  * page before definitively removing the page from the guest system.
147 			  struct page *page)
152 	balloon_page_enqueue_one(b_dev_info, page);
158  * balloon_page_dequeue - removes a page from balloon's page list and returns
159  *			  its address to allow the driver to release the page.
160  * @b_dev_info: balloon device descriptor where we will grab a page from.
162  * Driver must call this function to properly dequeue a previously enqueued page
169  * some enqueued pages - since the page list can be temporarily empty due to
175  * Return: struct page for the dequeued page, or NULL if no page was dequeued.
177 struct page *balloon_page_dequeue(struct balloon_dev_info *b_dev_info)
187 		 * If we are unable to dequeue a balloon page because the page
200 	return list_first_entry(&pages, struct page, lru);
206 static bool balloon_page_isolate(struct page *page, isolate_mode_t mode)
209 	struct balloon_dev_info *b_dev_info = balloon_page_device(page);
213 	list_del(&page->lru);
220 static void balloon_page_putback(struct page *page)
222 	struct balloon_dev_info *b_dev_info = balloon_page_device(page);
226 	list_add(&page->lru, &b_dev_info->pages);
231 /* move_to_new_page() counterpart for a ballooned page */
232 static int balloon_page_migrate(struct page *newpage, struct page *page,
235 	struct balloon_dev_info *balloon = balloon_page_device(page);
245 	VM_BUG_ON_PAGE(!PageLocked(page), page);
248 	return balloon->migratepage(balloon, newpage, page, mode);