155 struct stable_node {  struct
209 			struct stable_node *head;
312 	stable_node_cache = KSM_KMEM_CACHE(stable_node, 0);  in ksm_slab_init()
338 static __always_inline bool is_stable_node_chain(struct stable_node *chain)  in is_stable_node_chain()
343 static __always_inline bool is_stable_node_dup(struct stable_node *dup)  in is_stable_node_dup()
348 static inline void stable_node_chain_add_dup(struct stable_node *dup,  in stable_node_chain_add_dup()
349 					     struct stable_node *chain)  in stable_node_chain_add_dup()
358 static inline void __stable_node_dup_del(struct stable_node *dup)  in __stable_node_dup_del()
365 static inline void stable_node_dup_del(struct stable_node *dup)  in stable_node_dup_del()
395 static inline struct stable_node *alloc_stable_node(void)  in alloc_stable_node()
405 static inline void free_stable_node(struct stable_node *stable_node)  in free_stable_node()  argument
407 	VM_BUG_ON(stable_node->rmap_hlist_len &&  in free_stable_node()
408 		  !is_stable_node_chain(stable_node));  in free_stable_node()
409 	kmem_cache_free(stable_node_cache, stable_node);  in free_stable_node()
591 static struct stable_node *alloc_stable_node_chain(struct stable_node *dup,  in alloc_stable_node_chain()
594 	struct stable_node *chain = alloc_stable_node();  in alloc_stable_node_chain()
624 static inline void free_stable_node_chain(struct stable_node *chain,  in free_stable_node_chain()
632 static void remove_node_from_stable_tree(struct stable_node *stable_node)  in remove_node_from_stable_tree()  argument
637 	BUG_ON(stable_node->rmap_hlist_len < 0);  in remove_node_from_stable_tree()
639 	hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) {  in remove_node_from_stable_tree()
644 		VM_BUG_ON(stable_node->rmap_hlist_len <= 0);  in remove_node_from_stable_tree()
645 		stable_node->rmap_hlist_len--;  in remove_node_from_stable_tree()
663 	if (stable_node->head == &migrate_nodes)  in remove_node_from_stable_tree()
664 		list_del(&stable_node->list);  in remove_node_from_stable_tree()
666 		stable_node_dup_del(stable_node);  in remove_node_from_stable_tree()
667 	free_stable_node(stable_node);  in remove_node_from_stable_tree()
695 static struct page *get_ksm_page(struct stable_node *stable_node,  in get_ksm_page()  argument
702 	expected_mapping = (void *)((unsigned long)stable_node |  in get_ksm_page()
705 	kpfn = READ_ONCE(stable_node->kpfn); /* Address dependency. */  in get_ksm_page()
764 	if (READ_ONCE(stable_node->kpfn) != kpfn)  in get_ksm_page()
766 	remove_node_from_stable_tree(stable_node);  in get_ksm_page()
777 		struct stable_node *stable_node;  in remove_rmap_item_from_tree()  local
780 		stable_node = rmap_item->head;  in remove_rmap_item_from_tree()
781 		page = get_ksm_page(stable_node, GET_KSM_PAGE_LOCK);  in remove_rmap_item_from_tree()
789 		if (!hlist_empty(&stable_node->hlist))  in remove_rmap_item_from_tree()
793 		VM_BUG_ON(stable_node->rmap_hlist_len <= 0);  in remove_rmap_item_from_tree()
794 		stable_node->rmap_hlist_len--;  in remove_rmap_item_from_tree()
862 static inline struct stable_node *page_stable_node(struct page *page)  in page_stable_node()
868 					struct stable_node *stable_node)  in set_page_stable_node()  argument
870 	page->mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM);  in set_page_stable_node()
877 static int remove_stable_node(struct stable_node *stable_node)  in remove_stable_node()  argument
882 	page = get_ksm_page(stable_node, GET_KSM_PAGE_LOCK);  in remove_stable_node()
906 		remove_node_from_stable_tree(stable_node);  in remove_stable_node()
915 static int remove_stable_node_chain(struct stable_node *stable_node,  in remove_stable_node_chain()  argument
918 	struct stable_node *dup;  in remove_stable_node_chain()
921 	if (!is_stable_node_chain(stable_node)) {  in remove_stable_node_chain()
922 		VM_BUG_ON(is_stable_node_dup(stable_node));  in remove_stable_node_chain()
923 		if (remove_stable_node(stable_node))  in remove_stable_node_chain()
930 				  &stable_node->hlist, hlist_dup) {  in remove_stable_node_chain()
935 	BUG_ON(!hlist_empty(&stable_node->hlist));  in remove_stable_node_chain()
936 	free_stable_node_chain(stable_node, root);  in remove_stable_node_chain()
942 	struct stable_node *stable_node, *next;  in remove_all_stable_nodes()  local
948 			stable_node = rb_entry(root_stable_tree[nid].rb_node,  in remove_all_stable_nodes()
949 						struct stable_node, node);  in remove_all_stable_nodes()
950 			if (remove_stable_node_chain(stable_node,  in remove_all_stable_nodes()
958 	list_for_each_entry_safe(stable_node, next, &migrate_nodes, list) {  in remove_all_stable_nodes()
959 		if (remove_stable_node(stable_node))  in remove_all_stable_nodes()
1337 bool __is_page_sharing_candidate(struct stable_node *stable_node, int offset)  in __is_page_sharing_candidate()  argument
1339 	VM_BUG_ON(stable_node->rmap_hlist_len < 0);  in __is_page_sharing_candidate()
1346 	return stable_node->rmap_hlist_len &&  in __is_page_sharing_candidate()
1347 		stable_node->rmap_hlist_len + offset < ksm_max_page_sharing;  in __is_page_sharing_candidate()
1351 bool is_page_sharing_candidate(struct stable_node *stable_node)  in is_page_sharing_candidate()  argument
1353 	return __is_page_sharing_candidate(stable_node, 0);  in is_page_sharing_candidate()
1356 static struct page *stable_node_dup(struct stable_node **_stable_node_dup,  in stable_node_dup()
1357 				    struct stable_node **_stable_node,  in stable_node_dup()
1361 	struct stable_node *dup, *found = NULL, *stable_node = *_stable_node;  in stable_node_dup()  local
1368 	    time_before(jiffies, stable_node->chain_prune_time +  in stable_node_dup()
1373 		stable_node->chain_prune_time = jiffies;  in stable_node_dup()
1376 				  &stable_node->hlist, hlist_dup) {  in stable_node_dup()
1424 			BUG_ON(stable_node->hlist.first->next);  in stable_node_dup()
1430 			rb_replace_node(&stable_node->node, &found->node,  in stable_node_dup()
1432 			free_stable_node(stable_node);  in stable_node_dup()
1447 			stable_node = NULL;  in stable_node_dup()
1448 		} else if (stable_node->hlist.first != &found->hlist_dup &&  in stable_node_dup()
1467 				       &stable_node->hlist);  in stable_node_dup()
1475 static struct stable_node *stable_node_dup_any(struct stable_node *stable_node,  in stable_node_dup_any()  argument
1478 	if (!is_stable_node_chain(stable_node))  in stable_node_dup_any()
1479 		return stable_node;  in stable_node_dup_any()
1480 	if (hlist_empty(&stable_node->hlist)) {  in stable_node_dup_any()
1481 		free_stable_node_chain(stable_node, root);  in stable_node_dup_any()
1484 	return hlist_entry(stable_node->hlist.first,  in stable_node_dup_any()
1485 			   typeof(*stable_node), hlist_dup);  in stable_node_dup_any()
1502 static struct page *__stable_node_chain(struct stable_node **_stable_node_dup,  in __stable_node_chain()
1503 					struct stable_node **_stable_node,  in __stable_node_chain()
1507 	struct stable_node *stable_node = *_stable_node;  in __stable_node_chain()  local
1508 	if (!is_stable_node_chain(stable_node)) {  in __stable_node_chain()
1509 		if (is_page_sharing_candidate(stable_node)) {  in __stable_node_chain()
1510 			*_stable_node_dup = stable_node;  in __stable_node_chain()
1511 			return get_ksm_page(stable_node, GET_KSM_PAGE_NOLOCK);  in __stable_node_chain()
1524 static __always_inline struct page *chain_prune(struct stable_node **s_n_d,  in chain_prune()
1525 						struct stable_node **s_n,  in chain_prune()
1531 static __always_inline struct page *chain(struct stable_node **s_n_d,  in chain()
1532 					  struct stable_node *s_n,  in chain()
1535 	struct stable_node *old_stable_node = s_n;  in chain()
1559 	struct stable_node *stable_node, *stable_node_dup, *stable_node_any;  in stable_tree_search()  local
1560 	struct stable_node *page_node;  in stable_tree_search()
1580 		stable_node = rb_entry(*new, struct stable_node, node);  in stable_tree_search()
1582 		tree_page = chain_prune(&stable_node_dup, &stable_node,	root);  in stable_tree_search()
1601 			stable_node_any = stable_node_dup_any(stable_node,  in stable_tree_search()
1723 	if (stable_node_dup == stable_node) {  in stable_tree_search()
1743 		VM_BUG_ON(!is_stable_node_chain(stable_node));  in stable_tree_search()
1749 			stable_node_chain_add_dup(page_node, stable_node);  in stable_tree_search()
1774 	if (stable_node_dup == stable_node) {  in stable_tree_search()
1778 		stable_node = alloc_stable_node_chain(stable_node_dup,  in stable_tree_search()
1780 		if (!stable_node)  in stable_tree_search()
1789 	VM_BUG_ON(!is_stable_node_chain(stable_node));  in stable_tree_search()
1794 	stable_node_chain_add_dup(page_node, stable_node);  in stable_tree_search()
1805 static struct stable_node *stable_tree_insert(struct page *kpage)  in stable_tree_insert()
1812 	struct stable_node *stable_node, *stable_node_dup, *stable_node_any;  in stable_tree_insert()  local
1827 		stable_node = rb_entry(*new, struct stable_node, node);  in stable_tree_insert()
1829 		tree_page = chain(&stable_node_dup, stable_node, root);  in stable_tree_insert()
1836 			stable_node_any = stable_node_dup_any(stable_node,  in stable_tree_insert()
1895 		if (!is_stable_node_chain(stable_node)) {  in stable_tree_insert()
1896 			struct stable_node *orig = stable_node;  in stable_tree_insert()
1898 			stable_node = alloc_stable_node_chain(orig, root);  in stable_tree_insert()
1899 			if (!stable_node) {  in stable_tree_insert()
1904 		stable_node_chain_add_dup(stable_node_dup, stable_node);  in stable_tree_insert()
1997 			       struct stable_node *stable_node,  in stable_tree_append()  argument
2010 	BUG_ON(stable_node->rmap_hlist_len < 0);  in stable_tree_append()
2012 	stable_node->rmap_hlist_len++;  in stable_tree_append()
2015 		WARN_ON_ONCE(stable_node->rmap_hlist_len >  in stable_tree_append()
2018 	rmap_item->head = stable_node;  in stable_tree_append()
2020 	hlist_add_head(&rmap_item->hlist, &stable_node->hlist);  in stable_tree_append()
2042 	struct stable_node *stable_node;  in cmp_and_merge_page()  local
2048 	stable_node = page_stable_node(page);  in cmp_and_merge_page()
2049 	if (stable_node) {  in cmp_and_merge_page()
2050 		if (stable_node->head != &migrate_nodes &&  in cmp_and_merge_page()
2051 		    get_kpfn_nid(READ_ONCE(stable_node->kpfn)) !=  in cmp_and_merge_page()
2052 		    NUMA(stable_node->nid)) {  in cmp_and_merge_page()
2053 			stable_node_dup_del(stable_node);  in cmp_and_merge_page()
2054 			stable_node->head = &migrate_nodes;  in cmp_and_merge_page()
2055 			list_add(&stable_node->list, stable_node->head);  in cmp_and_merge_page()
2057 		if (stable_node->head != &migrate_nodes &&  in cmp_and_merge_page()
2058 		    rmap_item->head == stable_node)  in cmp_and_merge_page()
2064 		if (!is_page_sharing_candidate(stable_node))  in cmp_and_merge_page()
2070 	if (kpage == page && rmap_item->head == stable_node) {  in cmp_and_merge_page()
2161 			stable_node = stable_tree_insert(kpage);  in cmp_and_merge_page()
2162 			if (stable_node) {  in cmp_and_merge_page()
2163 				stable_tree_append(tree_rmap_item, stable_node,  in cmp_and_merge_page()
2165 				stable_tree_append(rmap_item, stable_node,  in cmp_and_merge_page()
2176 			if (!stable_node) {  in cmp_and_merge_page()
2258 			struct stable_node *stable_node, *next;  in scan_get_next_rmap_item()  local
2261 			list_for_each_entry_safe(stable_node, next,  in scan_get_next_rmap_item()
2263 				page = get_ksm_page(stable_node,  in scan_get_next_rmap_item()
2607 	struct stable_node *stable_node;  in rmap_walk_ksm()  local
2619 	stable_node = page_stable_node(page);  in rmap_walk_ksm()
2620 	if (!stable_node)  in rmap_walk_ksm()
2623 	hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) {  in rmap_walk_ksm()
2678 	struct stable_node *stable_node;  in ksm_migrate_page()  local
2684 	stable_node = page_stable_node(newpage);  in ksm_migrate_page()
2685 	if (stable_node) {  in ksm_migrate_page()
2686 		VM_BUG_ON_PAGE(stable_node->kpfn != page_to_pfn(oldpage), oldpage);  in ksm_migrate_page()
2687 		stable_node->kpfn = page_to_pfn(newpage);  in ksm_migrate_page()
2711 static bool stable_node_dup_remove_range(struct stable_node *stable_node,  in stable_node_dup_remove_range()  argument
2715 	if (stable_node->kpfn >= start_pfn &&  in stable_node_dup_remove_range()
2716 	    stable_node->kpfn < end_pfn) {  in stable_node_dup_remove_range()
2721 		remove_node_from_stable_tree(stable_node);  in stable_node_dup_remove_range()
2727 static bool stable_node_chain_remove_range(struct stable_node *stable_node,  in stable_node_chain_remove_range()  argument
2732 	struct stable_node *dup;  in stable_node_chain_remove_range()
2735 	if (!is_stable_node_chain(stable_node)) {  in stable_node_chain_remove_range()
2736 		VM_BUG_ON(is_stable_node_dup(stable_node));  in stable_node_chain_remove_range()
2737 		return stable_node_dup_remove_range(stable_node, start_pfn,  in stable_node_chain_remove_range()
2742 				  &stable_node->hlist, hlist_dup) {  in stable_node_chain_remove_range()
2746 	if (hlist_empty(&stable_node->hlist)) {  in stable_node_chain_remove_range()
2747 		free_stable_node_chain(stable_node, root);  in stable_node_chain_remove_range()
2756 	struct stable_node *stable_node, *next;  in ksm_check_stable_tree()  local
2763 			stable_node = rb_entry(node, struct stable_node, node);  in ksm_check_stable_tree()
2764 			if (stable_node_chain_remove_range(stable_node,  in ksm_check_stable_tree()
2774 	list_for_each_entry_safe(stable_node, next, &migrate_nodes, list) {  in ksm_check_stable_tree()
2775 		if (stable_node->kpfn >= start_pfn &&  in ksm_check_stable_tree()
2776 		    stable_node->kpfn < end_pfn)  in ksm_check_stable_tree()
2777 			remove_node_from_stable_tree(stable_node);  in ksm_check_stable_tree()