156 struct stable_node {  struct
210 			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()
590 static struct stable_node *alloc_stable_node_chain(struct stable_node *dup,  in alloc_stable_node_chain()
593 	struct stable_node *chain = alloc_stable_node();  in alloc_stable_node_chain()
623 static inline void free_stable_node_chain(struct stable_node *chain,  in free_stable_node_chain()
631 static void remove_node_from_stable_tree(struct stable_node *stable_node)  in remove_node_from_stable_tree()  argument
636 	BUG_ON(stable_node->rmap_hlist_len < 0);  in remove_node_from_stable_tree()
638 	hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) {  in remove_node_from_stable_tree()
643 		VM_BUG_ON(stable_node->rmap_hlist_len <= 0);  in remove_node_from_stable_tree()
644 		stable_node->rmap_hlist_len--;  in remove_node_from_stable_tree()
662 	if (stable_node->head == &migrate_nodes)  in remove_node_from_stable_tree()
663 		list_del(&stable_node->list);  in remove_node_from_stable_tree()
665 		stable_node_dup_del(stable_node);  in remove_node_from_stable_tree()
666 	free_stable_node(stable_node);  in remove_node_from_stable_tree()
688 static struct page *get_ksm_page(struct stable_node *stable_node, bool lock_it)  in get_ksm_page()  argument
694 	expected_mapping = (void *)((unsigned long)stable_node |  in get_ksm_page()
697 	kpfn = READ_ONCE(stable_node->kpfn); /* Address dependency. */  in get_ksm_page()
748 	if (READ_ONCE(stable_node->kpfn) != kpfn)  in get_ksm_page()
750 	remove_node_from_stable_tree(stable_node);  in get_ksm_page()
761 		struct stable_node *stable_node;  in remove_rmap_item_from_tree()  local
764 		stable_node = rmap_item->head;  in remove_rmap_item_from_tree()
765 		page = get_ksm_page(stable_node, true);  in remove_rmap_item_from_tree()
773 		if (!hlist_empty(&stable_node->hlist))  in remove_rmap_item_from_tree()
777 		VM_BUG_ON(stable_node->rmap_hlist_len <= 0);  in remove_rmap_item_from_tree()
778 		stable_node->rmap_hlist_len--;  in remove_rmap_item_from_tree()
845 static inline struct stable_node *page_stable_node(struct page *page)  in page_stable_node()
851 					struct stable_node *stable_node)  in set_page_stable_node()  argument
853 	page->mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM);  in set_page_stable_node()
860 static int remove_stable_node(struct stable_node *stable_node)  in remove_stable_node()  argument
865 	page = get_ksm_page(stable_node, true);  in remove_stable_node()
889 		remove_node_from_stable_tree(stable_node);  in remove_stable_node()
898 static int remove_stable_node_chain(struct stable_node *stable_node,  in remove_stable_node_chain()  argument
901 	struct stable_node *dup;  in remove_stable_node_chain()
904 	if (!is_stable_node_chain(stable_node)) {  in remove_stable_node_chain()
905 		VM_BUG_ON(is_stable_node_dup(stable_node));  in remove_stable_node_chain()
906 		if (remove_stable_node(stable_node))  in remove_stable_node_chain()
913 				  &stable_node->hlist, hlist_dup) {  in remove_stable_node_chain()
918 	BUG_ON(!hlist_empty(&stable_node->hlist));  in remove_stable_node_chain()
919 	free_stable_node_chain(stable_node, root);  in remove_stable_node_chain()
925 	struct stable_node *stable_node, *next;  in remove_all_stable_nodes()  local
931 			stable_node = rb_entry(root_stable_tree[nid].rb_node,  in remove_all_stable_nodes()
932 						struct stable_node, node);  in remove_all_stable_nodes()
933 			if (remove_stable_node_chain(stable_node,  in remove_all_stable_nodes()
941 	list_for_each_entry_safe(stable_node, next, &migrate_nodes, list) {  in remove_all_stable_nodes()
942 		if (remove_stable_node(stable_node))  in remove_all_stable_nodes()
1339 bool __is_page_sharing_candidate(struct stable_node *stable_node, int offset)  in __is_page_sharing_candidate()  argument
1341 	VM_BUG_ON(stable_node->rmap_hlist_len < 0);  in __is_page_sharing_candidate()
1348 	return stable_node->rmap_hlist_len &&  in __is_page_sharing_candidate()
1349 		stable_node->rmap_hlist_len + offset < ksm_max_page_sharing;  in __is_page_sharing_candidate()
1353 bool is_page_sharing_candidate(struct stable_node *stable_node)  in is_page_sharing_candidate()  argument
1355 	return __is_page_sharing_candidate(stable_node, 0);  in is_page_sharing_candidate()
1358 static struct page *stable_node_dup(struct stable_node **_stable_node_dup,  in stable_node_dup()
1359 				    struct stable_node **_stable_node,  in stable_node_dup()
1363 	struct stable_node *dup, *found = NULL, *stable_node = *_stable_node;  in stable_node_dup()  local
1370 	    time_before(jiffies, stable_node->chain_prune_time +  in stable_node_dup()
1375 		stable_node->chain_prune_time = jiffies;  in stable_node_dup()
1378 				  &stable_node->hlist, hlist_dup) {  in stable_node_dup()
1426 			BUG_ON(stable_node->hlist.first->next);  in stable_node_dup()
1432 			rb_replace_node(&stable_node->node, &found->node,  in stable_node_dup()
1434 			free_stable_node(stable_node);  in stable_node_dup()
1449 			stable_node = NULL;  in stable_node_dup()
1450 		} else if (stable_node->hlist.first != &found->hlist_dup &&  in stable_node_dup()
1469 				       &stable_node->hlist);  in stable_node_dup()
1477 static struct stable_node *stable_node_dup_any(struct stable_node *stable_node,  in stable_node_dup_any()  argument
1480 	if (!is_stable_node_chain(stable_node))  in stable_node_dup_any()
1481 		return stable_node;  in stable_node_dup_any()
1482 	if (hlist_empty(&stable_node->hlist)) {  in stable_node_dup_any()
1483 		free_stable_node_chain(stable_node, root);  in stable_node_dup_any()
1486 	return hlist_entry(stable_node->hlist.first,  in stable_node_dup_any()
1487 			   typeof(*stable_node), hlist_dup);  in stable_node_dup_any()
1504 static struct page *__stable_node_chain(struct stable_node **_stable_node_dup,  in __stable_node_chain()
1505 					struct stable_node **_stable_node,  in __stable_node_chain()
1509 	struct stable_node *stable_node = *_stable_node;  in __stable_node_chain()  local
1510 	if (!is_stable_node_chain(stable_node)) {  in __stable_node_chain()
1511 		if (is_page_sharing_candidate(stable_node)) {  in __stable_node_chain()
1512 			*_stable_node_dup = stable_node;  in __stable_node_chain()
1513 			return get_ksm_page(stable_node, false);  in __stable_node_chain()
1526 static __always_inline struct page *chain_prune(struct stable_node **s_n_d,  in chain_prune()
1527 						struct stable_node **s_n,  in chain_prune()
1533 static __always_inline struct page *chain(struct stable_node **s_n_d,  in chain()
1534 					  struct stable_node *s_n,  in chain()
1537 	struct stable_node *old_stable_node = s_n;  in chain()
1561 	struct stable_node *stable_node, *stable_node_dup, *stable_node_any;  in stable_tree_search()  local
1562 	struct stable_node *page_node;  in stable_tree_search()
1582 		stable_node = rb_entry(*new, struct stable_node, node);  in stable_tree_search()
1584 		tree_page = chain_prune(&stable_node_dup, &stable_node,	root);  in stable_tree_search()
1603 			stable_node_any = stable_node_dup_any(stable_node,  in stable_tree_search()
1719 	if (stable_node_dup == stable_node) {  in stable_tree_search()
1739 		VM_BUG_ON(!is_stable_node_chain(stable_node));  in stable_tree_search()
1745 			stable_node_chain_add_dup(page_node, stable_node);  in stable_tree_search()
1770 	if (stable_node_dup == stable_node) {  in stable_tree_search()
1774 		stable_node = alloc_stable_node_chain(stable_node_dup,  in stable_tree_search()
1776 		if (!stable_node)  in stable_tree_search()
1785 	VM_BUG_ON(!is_stable_node_chain(stable_node));  in stable_tree_search()
1790 	stable_node_chain_add_dup(page_node, stable_node);  in stable_tree_search()
1801 static struct stable_node *stable_tree_insert(struct page *kpage)  in stable_tree_insert()
1808 	struct stable_node *stable_node, *stable_node_dup, *stable_node_any;  in stable_tree_insert()  local
1823 		stable_node = rb_entry(*new, struct stable_node, node);  in stable_tree_insert()
1825 		tree_page = chain(&stable_node_dup, stable_node, root);  in stable_tree_insert()
1832 			stable_node_any = stable_node_dup_any(stable_node,  in stable_tree_insert()
1890 		if (!is_stable_node_chain(stable_node)) {  in stable_tree_insert()
1891 			struct stable_node *orig = stable_node;  in stable_tree_insert()
1893 			stable_node = alloc_stable_node_chain(orig, root);  in stable_tree_insert()
1894 			if (!stable_node) {  in stable_tree_insert()
1899 		stable_node_chain_add_dup(stable_node_dup, stable_node);  in stable_tree_insert()
1992 			       struct stable_node *stable_node,  in stable_tree_append()  argument
2005 	BUG_ON(stable_node->rmap_hlist_len < 0);  in stable_tree_append()
2007 	stable_node->rmap_hlist_len++;  in stable_tree_append()
2010 		WARN_ON_ONCE(stable_node->rmap_hlist_len >  in stable_tree_append()
2013 	rmap_item->head = stable_node;  in stable_tree_append()
2015 	hlist_add_head(&rmap_item->hlist, &stable_node->hlist);  in stable_tree_append()
2037 	struct stable_node *stable_node;  in cmp_and_merge_page()  local
2043 	stable_node = page_stable_node(page);  in cmp_and_merge_page()
2044 	if (stable_node) {  in cmp_and_merge_page()
2045 		if (stable_node->head != &migrate_nodes &&  in cmp_and_merge_page()
2046 		    get_kpfn_nid(READ_ONCE(stable_node->kpfn)) !=  in cmp_and_merge_page()
2047 		    NUMA(stable_node->nid)) {  in cmp_and_merge_page()
2048 			stable_node_dup_del(stable_node);  in cmp_and_merge_page()
2049 			stable_node->head = &migrate_nodes;  in cmp_and_merge_page()
2050 			list_add(&stable_node->list, stable_node->head);  in cmp_and_merge_page()
2052 		if (stable_node->head != &migrate_nodes &&  in cmp_and_merge_page()
2053 		    rmap_item->head == stable_node)  in cmp_and_merge_page()
2059 		if (!is_page_sharing_candidate(stable_node))  in cmp_and_merge_page()
2065 	if (kpage == page && rmap_item->head == stable_node) {  in cmp_and_merge_page()
2145 			stable_node = stable_tree_insert(kpage);  in cmp_and_merge_page()
2146 			if (stable_node) {  in cmp_and_merge_page()
2147 				stable_tree_append(tree_rmap_item, stable_node,  in cmp_and_merge_page()
2149 				stable_tree_append(rmap_item, stable_node,  in cmp_and_merge_page()
2160 			if (!stable_node) {  in cmp_and_merge_page()
2242 			struct stable_node *stable_node, *next;  in scan_get_next_rmap_item()  local
2245 			list_for_each_entry_safe(stable_node, next,  in scan_get_next_rmap_item()
2247 				page = get_ksm_page(stable_node, false);  in scan_get_next_rmap_item()
2581 	struct stable_node *stable_node;  in rmap_walk_ksm()  local
2593 	stable_node = page_stable_node(page);  in rmap_walk_ksm()
2594 	if (!stable_node)  in rmap_walk_ksm()
2597 	hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) {  in rmap_walk_ksm()
2646 	struct stable_node *stable_node;  in ksm_migrate_page()  local
2652 	stable_node = page_stable_node(newpage);  in ksm_migrate_page()
2653 	if (stable_node) {  in ksm_migrate_page()
2654 		VM_BUG_ON_PAGE(stable_node->kpfn != page_to_pfn(oldpage), oldpage);  in ksm_migrate_page()
2655 		stable_node->kpfn = page_to_pfn(newpage);  in ksm_migrate_page()
2679 static bool stable_node_dup_remove_range(struct stable_node *stable_node,  in stable_node_dup_remove_range()  argument
2683 	if (stable_node->kpfn >= start_pfn &&  in stable_node_dup_remove_range()
2684 	    stable_node->kpfn < end_pfn) {  in stable_node_dup_remove_range()
2689 		remove_node_from_stable_tree(stable_node);  in stable_node_dup_remove_range()
2695 static bool stable_node_chain_remove_range(struct stable_node *stable_node,  in stable_node_chain_remove_range()  argument
2700 	struct stable_node *dup;  in stable_node_chain_remove_range()
2703 	if (!is_stable_node_chain(stable_node)) {  in stable_node_chain_remove_range()
2704 		VM_BUG_ON(is_stable_node_dup(stable_node));  in stable_node_chain_remove_range()
2705 		return stable_node_dup_remove_range(stable_node, start_pfn,  in stable_node_chain_remove_range()
2710 				  &stable_node->hlist, hlist_dup) {  in stable_node_chain_remove_range()
2714 	if (hlist_empty(&stable_node->hlist)) {  in stable_node_chain_remove_range()
2715 		free_stable_node_chain(stable_node, root);  in stable_node_chain_remove_range()
2724 	struct stable_node *stable_node, *next;  in ksm_check_stable_tree()  local
2731 			stable_node = rb_entry(node, struct stable_node, node);  in ksm_check_stable_tree()
2732 			if (stable_node_chain_remove_range(stable_node,  in ksm_check_stable_tree()
2742 	list_for_each_entry_safe(stable_node, next, &migrate_nodes, list) {  in ksm_check_stable_tree()
2743 		if (stable_node->kpfn >= start_pfn &&  in ksm_check_stable_tree()
2744 		    stable_node->kpfn < end_pfn)  in ksm_check_stable_tree()
2745 			remove_node_from_stable_tree(stable_node);  in ksm_check_stable_tree()