155 struct stable_node {  struct
209 			struct stable_node *head;
310 	stable_node_cache = KSM_KMEM_CACHE(stable_node, 0);  in ksm_slab_init()
336 static __always_inline bool is_stable_node_chain(struct stable_node *chain)  in is_stable_node_chain()
341 static __always_inline bool is_stable_node_dup(struct stable_node *dup)  in is_stable_node_dup()
346 static inline void stable_node_chain_add_dup(struct stable_node *dup,  in stable_node_chain_add_dup()
347 					     struct stable_node *chain)  in stable_node_chain_add_dup()
356 static inline void __stable_node_dup_del(struct stable_node *dup)  in __stable_node_dup_del()
363 static inline void stable_node_dup_del(struct stable_node *dup)  in stable_node_dup_del()
393 static inline struct stable_node *alloc_stable_node(void)  in alloc_stable_node()
403 static inline void free_stable_node(struct stable_node *stable_node)  in free_stable_node()  argument
405 	VM_BUG_ON(stable_node->rmap_hlist_len &&  in free_stable_node()
406 		  !is_stable_node_chain(stable_node));  in free_stable_node()
407 	kmem_cache_free(stable_node_cache, stable_node);  in free_stable_node()
587 static struct stable_node *alloc_stable_node_chain(struct stable_node *dup,  in alloc_stable_node_chain()
590 	struct stable_node *chain = alloc_stable_node();  in alloc_stable_node_chain()
620 static inline void free_stable_node_chain(struct stable_node *chain,  in free_stable_node_chain()
628 static void remove_node_from_stable_tree(struct stable_node *stable_node)  in remove_node_from_stable_tree()  argument
633 	BUG_ON(stable_node->rmap_hlist_len < 0);  in remove_node_from_stable_tree()
635 	hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) {  in remove_node_from_stable_tree()
640 		VM_BUG_ON(stable_node->rmap_hlist_len <= 0);  in remove_node_from_stable_tree()
641 		stable_node->rmap_hlist_len--;  in remove_node_from_stable_tree()
657 	if (stable_node->head == &migrate_nodes)  in remove_node_from_stable_tree()
658 		list_del(&stable_node->list);  in remove_node_from_stable_tree()
660 		stable_node_dup_del(stable_node);  in remove_node_from_stable_tree()
661 	free_stable_node(stable_node);  in remove_node_from_stable_tree()
689 static struct page *get_ksm_page(struct stable_node *stable_node,  in get_ksm_page()  argument
696 	expected_mapping = (void *)((unsigned long)stable_node |  in get_ksm_page()
699 	kpfn = READ_ONCE(stable_node->kpfn); /* Address dependency. */  in get_ksm_page()
758 	if (READ_ONCE(stable_node->kpfn) != kpfn)  in get_ksm_page()
760 	remove_node_from_stable_tree(stable_node);  in get_ksm_page()
771 		struct stable_node *stable_node;  in remove_rmap_item_from_tree()  local
774 		stable_node = rmap_item->head;  in remove_rmap_item_from_tree()
775 		page = get_ksm_page(stable_node, GET_KSM_PAGE_LOCK);  in remove_rmap_item_from_tree()
783 		if (!hlist_empty(&stable_node->hlist))  in remove_rmap_item_from_tree()
787 		VM_BUG_ON(stable_node->rmap_hlist_len <= 0);  in remove_rmap_item_from_tree()
788 		stable_node->rmap_hlist_len--;  in remove_rmap_item_from_tree()
855 static inline struct stable_node *page_stable_node(struct page *page)  in page_stable_node()
861 					struct stable_node *stable_node)  in set_page_stable_node()  argument
863 	page->mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM);  in set_page_stable_node()
870 static int remove_stable_node(struct stable_node *stable_node)  in remove_stable_node()  argument
875 	page = get_ksm_page(stable_node, GET_KSM_PAGE_LOCK);  in remove_stable_node()
899 		remove_node_from_stable_tree(stable_node);  in remove_stable_node()
908 static int remove_stable_node_chain(struct stable_node *stable_node,  in remove_stable_node_chain()  argument
911 	struct stable_node *dup;  in remove_stable_node_chain()
914 	if (!is_stable_node_chain(stable_node)) {  in remove_stable_node_chain()
915 		VM_BUG_ON(is_stable_node_dup(stable_node));  in remove_stable_node_chain()
916 		if (remove_stable_node(stable_node))  in remove_stable_node_chain()
923 				  &stable_node->hlist, hlist_dup) {  in remove_stable_node_chain()
928 	BUG_ON(!hlist_empty(&stable_node->hlist));  in remove_stable_node_chain()
929 	free_stable_node_chain(stable_node, root);  in remove_stable_node_chain()
935 	struct stable_node *stable_node, *next;  in remove_all_stable_nodes()  local
941 			stable_node = rb_entry(root_stable_tree[nid].rb_node,  in remove_all_stable_nodes()
942 						struct stable_node, node);  in remove_all_stable_nodes()
943 			if (remove_stable_node_chain(stable_node,  in remove_all_stable_nodes()
951 	list_for_each_entry_safe(stable_node, next, &migrate_nodes, list) {  in remove_all_stable_nodes()
952 		if (remove_stable_node(stable_node))  in remove_all_stable_nodes()
1330 bool __is_page_sharing_candidate(struct stable_node *stable_node, int offset)  in __is_page_sharing_candidate()  argument
1332 	VM_BUG_ON(stable_node->rmap_hlist_len < 0);  in __is_page_sharing_candidate()
1339 	return stable_node->rmap_hlist_len &&  in __is_page_sharing_candidate()
1340 		stable_node->rmap_hlist_len + offset < ksm_max_page_sharing;  in __is_page_sharing_candidate()
1344 bool is_page_sharing_candidate(struct stable_node *stable_node)  in is_page_sharing_candidate()  argument
1346 	return __is_page_sharing_candidate(stable_node, 0);  in is_page_sharing_candidate()
1349 static struct page *stable_node_dup(struct stable_node **_stable_node_dup,  in stable_node_dup()
1350 				    struct stable_node **_stable_node,  in stable_node_dup()
1354 	struct stable_node *dup, *found = NULL, *stable_node = *_stable_node;  in stable_node_dup()  local
1361 	    time_before(jiffies, stable_node->chain_prune_time +  in stable_node_dup()
1366 		stable_node->chain_prune_time = jiffies;  in stable_node_dup()
1369 				  &stable_node->hlist, hlist_dup) {  in stable_node_dup()
1417 			BUG_ON(stable_node->hlist.first->next);  in stable_node_dup()
1423 			rb_replace_node(&stable_node->node, &found->node,  in stable_node_dup()
1425 			free_stable_node(stable_node);  in stable_node_dup()
1440 			stable_node = NULL;  in stable_node_dup()
1441 		} else if (stable_node->hlist.first != &found->hlist_dup &&  in stable_node_dup()
1460 				       &stable_node->hlist);  in stable_node_dup()
1468 static struct stable_node *stable_node_dup_any(struct stable_node *stable_node,  in stable_node_dup_any()  argument
1471 	if (!is_stable_node_chain(stable_node))  in stable_node_dup_any()
1472 		return stable_node;  in stable_node_dup_any()
1473 	if (hlist_empty(&stable_node->hlist)) {  in stable_node_dup_any()
1474 		free_stable_node_chain(stable_node, root);  in stable_node_dup_any()
1477 	return hlist_entry(stable_node->hlist.first,  in stable_node_dup_any()
1478 			   typeof(*stable_node), hlist_dup);  in stable_node_dup_any()
1495 static struct page *__stable_node_chain(struct stable_node **_stable_node_dup,  in __stable_node_chain()
1496 					struct stable_node **_stable_node,  in __stable_node_chain()
1500 	struct stable_node *stable_node = *_stable_node;  in __stable_node_chain()  local
1501 	if (!is_stable_node_chain(stable_node)) {  in __stable_node_chain()
1502 		if (is_page_sharing_candidate(stable_node)) {  in __stable_node_chain()
1503 			*_stable_node_dup = stable_node;  in __stable_node_chain()
1504 			return get_ksm_page(stable_node, GET_KSM_PAGE_NOLOCK);  in __stable_node_chain()
1517 static __always_inline struct page *chain_prune(struct stable_node **s_n_d,  in chain_prune()
1518 						struct stable_node **s_n,  in chain_prune()
1524 static __always_inline struct page *chain(struct stable_node **s_n_d,  in chain()
1525 					  struct stable_node *s_n,  in chain()
1528 	struct stable_node *old_stable_node = s_n;  in chain()
1552 	struct stable_node *stable_node, *stable_node_dup, *stable_node_any;  in stable_tree_search()  local
1553 	struct stable_node *page_node;  in stable_tree_search()
1573 		stable_node = rb_entry(*new, struct stable_node, node);  in stable_tree_search()
1575 		tree_page = chain_prune(&stable_node_dup, &stable_node,	root);  in stable_tree_search()
1594 			stable_node_any = stable_node_dup_any(stable_node,  in stable_tree_search()
1716 	if (stable_node_dup == stable_node) {  in stable_tree_search()
1736 		VM_BUG_ON(!is_stable_node_chain(stable_node));  in stable_tree_search()
1742 			stable_node_chain_add_dup(page_node, stable_node);  in stable_tree_search()
1767 	if (stable_node_dup == stable_node) {  in stable_tree_search()
1770 		stable_node = alloc_stable_node_chain(stable_node_dup,  in stable_tree_search()
1772 		if (!stable_node)  in stable_tree_search()
1785 	stable_node_chain_add_dup(page_node, stable_node);  in stable_tree_search()
1796 static struct stable_node *stable_tree_insert(struct page *kpage)  in stable_tree_insert()
1803 	struct stable_node *stable_node, *stable_node_dup, *stable_node_any;  in stable_tree_insert()  local
1818 		stable_node = rb_entry(*new, struct stable_node, node);  in stable_tree_insert()
1820 		tree_page = chain(&stable_node_dup, stable_node, root);  in stable_tree_insert()
1827 			stable_node_any = stable_node_dup_any(stable_node,  in stable_tree_insert()
1886 		if (!is_stable_node_chain(stable_node)) {  in stable_tree_insert()
1887 			struct stable_node *orig = stable_node;  in stable_tree_insert()
1889 			stable_node = alloc_stable_node_chain(orig, root);  in stable_tree_insert()
1890 			if (!stable_node) {  in stable_tree_insert()
1895 		stable_node_chain_add_dup(stable_node_dup, stable_node);  in stable_tree_insert()
1988 			       struct stable_node *stable_node,  in stable_tree_append()  argument
2001 	BUG_ON(stable_node->rmap_hlist_len < 0);  in stable_tree_append()
2003 	stable_node->rmap_hlist_len++;  in stable_tree_append()
2006 		WARN_ON_ONCE(stable_node->rmap_hlist_len >  in stable_tree_append()
2009 	rmap_item->head = stable_node;  in stable_tree_append()
2011 	hlist_add_head(&rmap_item->hlist, &stable_node->hlist);  in stable_tree_append()
2033 	struct stable_node *stable_node;  in cmp_and_merge_page()  local
2039 	stable_node = page_stable_node(page);  in cmp_and_merge_page()
2040 	if (stable_node) {  in cmp_and_merge_page()
2041 		if (stable_node->head != &migrate_nodes &&  in cmp_and_merge_page()
2042 		    get_kpfn_nid(READ_ONCE(stable_node->kpfn)) !=  in cmp_and_merge_page()
2043 		    NUMA(stable_node->nid)) {  in cmp_and_merge_page()
2044 			stable_node_dup_del(stable_node);  in cmp_and_merge_page()
2045 			stable_node->head = &migrate_nodes;  in cmp_and_merge_page()
2046 			list_add(&stable_node->list, stable_node->head);  in cmp_and_merge_page()
2048 		if (stable_node->head != &migrate_nodes &&  in cmp_and_merge_page()
2049 		    rmap_item->head == stable_node)  in cmp_and_merge_page()
2055 		if (!is_page_sharing_candidate(stable_node))  in cmp_and_merge_page()
2061 	if (kpage == page && rmap_item->head == stable_node) {  in cmp_and_merge_page()
2152 			stable_node = stable_tree_insert(kpage);  in cmp_and_merge_page()
2153 			if (stable_node) {  in cmp_and_merge_page()
2154 				stable_tree_append(tree_rmap_item, stable_node,  in cmp_and_merge_page()
2156 				stable_tree_append(rmap_item, stable_node,  in cmp_and_merge_page()
2167 			if (!stable_node) {  in cmp_and_merge_page()
2249 			struct stable_node *stable_node, *next;  in scan_get_next_rmap_item()  local
2252 			list_for_each_entry_safe(stable_node, next,  in scan_get_next_rmap_item()
2254 				page = get_ksm_page(stable_node,  in scan_get_next_rmap_item()
2598 	struct stable_node *stable_node;  in rmap_walk_ksm()  local
2610 	stable_node = page_stable_node(page);  in rmap_walk_ksm()
2611 	if (!stable_node)  in rmap_walk_ksm()
2614 	hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) {  in rmap_walk_ksm()
2663 	struct stable_node *stable_node;  in ksm_migrate_page()  local
2669 	stable_node = page_stable_node(newpage);  in ksm_migrate_page()
2670 	if (stable_node) {  in ksm_migrate_page()
2671 		VM_BUG_ON_PAGE(stable_node->kpfn != page_to_pfn(oldpage), oldpage);  in ksm_migrate_page()
2672 		stable_node->kpfn = page_to_pfn(newpage);  in ksm_migrate_page()
2696 static bool stable_node_dup_remove_range(struct stable_node *stable_node,  in stable_node_dup_remove_range()  argument
2700 	if (stable_node->kpfn >= start_pfn &&  in stable_node_dup_remove_range()
2701 	    stable_node->kpfn < end_pfn) {  in stable_node_dup_remove_range()
2706 		remove_node_from_stable_tree(stable_node);  in stable_node_dup_remove_range()
2712 static bool stable_node_chain_remove_range(struct stable_node *stable_node,  in stable_node_chain_remove_range()  argument
2717 	struct stable_node *dup;  in stable_node_chain_remove_range()
2720 	if (!is_stable_node_chain(stable_node)) {  in stable_node_chain_remove_range()
2721 		VM_BUG_ON(is_stable_node_dup(stable_node));  in stable_node_chain_remove_range()
2722 		return stable_node_dup_remove_range(stable_node, start_pfn,  in stable_node_chain_remove_range()
2727 				  &stable_node->hlist, hlist_dup) {  in stable_node_chain_remove_range()
2731 	if (hlist_empty(&stable_node->hlist)) {  in stable_node_chain_remove_range()
2732 		free_stable_node_chain(stable_node, root);  in stable_node_chain_remove_range()
2741 	struct stable_node *stable_node, *next;  in ksm_check_stable_tree()  local
2748 			stable_node = rb_entry(node, struct stable_node, node);  in ksm_check_stable_tree()
2749 			if (stable_node_chain_remove_range(stable_node,  in ksm_check_stable_tree()
2759 	list_for_each_entry_safe(stable_node, next, &migrate_nodes, list) {  in ksm_check_stable_tree()
2760 		if (stable_node->kpfn >= start_pfn &&  in ksm_check_stable_tree()
2761 		    stable_node->kpfn < end_pfn)  in ksm_check_stable_tree()
2762 			remove_node_from_stable_tree(stable_node);  in ksm_check_stable_tree()