402 static inline void free_stable_node(struct ksm_stable_node *stable_node)  in free_stable_node()  argument
404 	VM_BUG_ON(stable_node->rmap_hlist_len &&  in free_stable_node()
405 		  !is_stable_node_chain(stable_node));  in free_stable_node()
406 	kmem_cache_free(stable_node_cache, stable_node);  in free_stable_node()
600 static void remove_node_from_stable_tree(struct ksm_stable_node *stable_node)  in remove_node_from_stable_tree()  argument
605 	BUG_ON(stable_node->rmap_hlist_len < 0);  in remove_node_from_stable_tree()
607 	hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) {  in remove_node_from_stable_tree()
615 		VM_BUG_ON(stable_node->rmap_hlist_len <= 0);  in remove_node_from_stable_tree()
616 		stable_node->rmap_hlist_len--;  in remove_node_from_stable_tree()
632 	if (stable_node->head == &migrate_nodes)  in remove_node_from_stable_tree()
633 		list_del(&stable_node->list);  in remove_node_from_stable_tree()
635 		stable_node_dup_del(stable_node);  in remove_node_from_stable_tree()
636 	free_stable_node(stable_node);  in remove_node_from_stable_tree()
664 static struct page *get_ksm_page(struct ksm_stable_node *stable_node,  in get_ksm_page()  argument
671 	expected_mapping = (void *)((unsigned long)stable_node |  in get_ksm_page()
674 	kpfn = READ_ONCE(stable_node->kpfn); /* Address dependency. */  in get_ksm_page()
733 	if (READ_ONCE(stable_node->kpfn) != kpfn)  in get_ksm_page()
735 	remove_node_from_stable_tree(stable_node);  in get_ksm_page()
746 		struct ksm_stable_node *stable_node;  in remove_rmap_item_from_tree()  local
749 		stable_node = rmap_item->head;  in remove_rmap_item_from_tree()
750 		page = get_ksm_page(stable_node, GET_KSM_PAGE_LOCK);  in remove_rmap_item_from_tree()
758 		if (!hlist_empty(&stable_node->hlist))  in remove_rmap_item_from_tree()
765 		VM_BUG_ON(stable_node->rmap_hlist_len <= 0);  in remove_rmap_item_from_tree()
766 		stable_node->rmap_hlist_len--;  in remove_rmap_item_from_tree()
844 					struct ksm_stable_node *stable_node)  in set_page_stable_node()  argument
847 	page->mapping = (void *)((unsigned long)stable_node | PAGE_MAPPING_KSM);  in set_page_stable_node()
854 static int remove_stable_node(struct ksm_stable_node *stable_node)  in remove_stable_node()  argument
859 	page = get_ksm_page(stable_node, GET_KSM_PAGE_LOCK);  in remove_stable_node()
883 		remove_node_from_stable_tree(stable_node);  in remove_stable_node()
892 static int remove_stable_node_chain(struct ksm_stable_node *stable_node,  in remove_stable_node_chain()  argument
898 	if (!is_stable_node_chain(stable_node)) {  in remove_stable_node_chain()
899 		VM_BUG_ON(is_stable_node_dup(stable_node));  in remove_stable_node_chain()
900 		if (remove_stable_node(stable_node))  in remove_stable_node_chain()
907 				  &stable_node->hlist, hlist_dup) {  in remove_stable_node_chain()
912 	BUG_ON(!hlist_empty(&stable_node->hlist));  in remove_stable_node_chain()
913 	free_stable_node_chain(stable_node, root);  in remove_stable_node_chain()
919 	struct ksm_stable_node *stable_node, *next;  in remove_all_stable_nodes()  local
925 			stable_node = rb_entry(root_stable_tree[nid].rb_node,  in remove_all_stable_nodes()
927 			if (remove_stable_node_chain(stable_node,  in remove_all_stable_nodes()
935 	list_for_each_entry_safe(stable_node, next, &migrate_nodes, list) {  in remove_all_stable_nodes()
936 		if (remove_stable_node(stable_node))  in remove_all_stable_nodes()
1329 bool __is_page_sharing_candidate(struct ksm_stable_node *stable_node, int offset)  in __is_page_sharing_candidate()  argument
1331 	VM_BUG_ON(stable_node->rmap_hlist_len < 0);  in __is_page_sharing_candidate()
1338 	return stable_node->rmap_hlist_len &&  in __is_page_sharing_candidate()
1339 		stable_node->rmap_hlist_len + offset < ksm_max_page_sharing;  in __is_page_sharing_candidate()
1343 bool is_page_sharing_candidate(struct ksm_stable_node *stable_node)  in is_page_sharing_candidate()  argument
1345 	return __is_page_sharing_candidate(stable_node, 0);  in is_page_sharing_candidate()
1353 	struct ksm_stable_node *dup, *found = NULL, *stable_node = *_stable_node;  in stable_node_dup()  local
1360 	    time_before(jiffies, stable_node->chain_prune_time +  in stable_node_dup()
1365 		stable_node->chain_prune_time = jiffies;  in stable_node_dup()
1368 				  &stable_node->hlist, hlist_dup) {  in stable_node_dup()
1416 			BUG_ON(stable_node->hlist.first->next);  in stable_node_dup()
1422 			rb_replace_node(&stable_node->node, &found->node,  in stable_node_dup()
1424 			free_stable_node(stable_node);  in stable_node_dup()
1439 			stable_node = NULL;  in stable_node_dup()
1440 		} else if (stable_node->hlist.first != &found->hlist_dup &&  in stable_node_dup()
1459 				       &stable_node->hlist);  in stable_node_dup()
1467 static struct ksm_stable_node *stable_node_dup_any(struct ksm_stable_node *stable_node,  in stable_node_dup_any()  argument
1470 	if (!is_stable_node_chain(stable_node))  in stable_node_dup_any()
1471 		return stable_node;  in stable_node_dup_any()
1472 	if (hlist_empty(&stable_node->hlist)) {  in stable_node_dup_any()
1473 		free_stable_node_chain(stable_node, root);  in stable_node_dup_any()
1476 	return hlist_entry(stable_node->hlist.first,  in stable_node_dup_any()
1477 			   typeof(*stable_node), hlist_dup);  in stable_node_dup_any()
1499 	struct ksm_stable_node *stable_node = *_stable_node;  in __stable_node_chain()  local
1500 	if (!is_stable_node_chain(stable_node)) {  in __stable_node_chain()
1501 		if (is_page_sharing_candidate(stable_node)) {  in __stable_node_chain()
1502 			*_stable_node_dup = stable_node;  in __stable_node_chain()
1503 			return get_ksm_page(stable_node, GET_KSM_PAGE_NOLOCK);  in __stable_node_chain()
1551 	struct ksm_stable_node *stable_node, *stable_node_dup, *stable_node_any;  in stable_tree_search()  local
1572 		stable_node = rb_entry(*new, struct ksm_stable_node, node);  in stable_tree_search()
1574 		tree_page = chain_prune(&stable_node_dup, &stable_node,	root);  in stable_tree_search()
1593 			stable_node_any = stable_node_dup_any(stable_node,  in stable_tree_search()
1715 	if (stable_node_dup == stable_node) {  in stable_tree_search()
1735 		VM_BUG_ON(!is_stable_node_chain(stable_node));  in stable_tree_search()
1741 			stable_node_chain_add_dup(page_node, stable_node);  in stable_tree_search()
1766 	if (stable_node_dup == stable_node) {  in stable_tree_search()
1769 		stable_node = alloc_stable_node_chain(stable_node_dup,  in stable_tree_search()
1771 		if (!stable_node)  in stable_tree_search()
1784 	stable_node_chain_add_dup(page_node, stable_node);  in stable_tree_search()
1802 	struct ksm_stable_node *stable_node, *stable_node_dup, *stable_node_any;  in stable_tree_insert()  local
1817 		stable_node = rb_entry(*new, struct ksm_stable_node, node);  in stable_tree_insert()
1819 		tree_page = chain(&stable_node_dup, stable_node, root);  in stable_tree_insert()
1826 			stable_node_any = stable_node_dup_any(stable_node,  in stable_tree_insert()
1885 		if (!is_stable_node_chain(stable_node)) {  in stable_tree_insert()
1886 			struct ksm_stable_node *orig = stable_node;  in stable_tree_insert()
1888 			stable_node = alloc_stable_node_chain(orig, root);  in stable_tree_insert()
1889 			if (!stable_node) {  in stable_tree_insert()
1894 		stable_node_chain_add_dup(stable_node_dup, stable_node);  in stable_tree_insert()
1987 			       struct ksm_stable_node *stable_node,  in stable_tree_append()  argument
2000 	BUG_ON(stable_node->rmap_hlist_len < 0);  in stable_tree_append()
2002 	stable_node->rmap_hlist_len++;  in stable_tree_append()
2005 		WARN_ON_ONCE(stable_node->rmap_hlist_len >  in stable_tree_append()
2008 	rmap_item->head = stable_node;  in stable_tree_append()
2010 	hlist_add_head(&rmap_item->hlist, &stable_node->hlist);  in stable_tree_append()
2034 	struct ksm_stable_node *stable_node;  in cmp_and_merge_page()  local
2040 	stable_node = page_stable_node(page);  in cmp_and_merge_page()
2041 	if (stable_node) {  in cmp_and_merge_page()
2042 		if (stable_node->head != &migrate_nodes &&  in cmp_and_merge_page()
2043 		    get_kpfn_nid(READ_ONCE(stable_node->kpfn)) !=  in cmp_and_merge_page()
2044 		    NUMA(stable_node->nid)) {  in cmp_and_merge_page()
2045 			stable_node_dup_del(stable_node);  in cmp_and_merge_page()
2046 			stable_node->head = &migrate_nodes;  in cmp_and_merge_page()
2047 			list_add(&stable_node->list, stable_node->head);  in cmp_and_merge_page()
2049 		if (stable_node->head != &migrate_nodes &&  in cmp_and_merge_page()
2050 		    rmap_item->head == stable_node)  in cmp_and_merge_page()
2056 		if (!is_page_sharing_candidate(stable_node))  in cmp_and_merge_page()
2062 	if (kpage == page && rmap_item->head == stable_node) {  in cmp_and_merge_page()
2153 			stable_node = stable_tree_insert(kpage);  in cmp_and_merge_page()
2154 			if (stable_node) {  in cmp_and_merge_page()
2155 				stable_tree_append(tree_rmap_item, stable_node,  in cmp_and_merge_page()
2157 				stable_tree_append(rmap_item, stable_node,  in cmp_and_merge_page()
2168 			if (!stable_node) {  in cmp_and_merge_page()
2253 			struct ksm_stable_node *stable_node, *next;  in scan_get_next_rmap_item()  local
2256 			list_for_each_entry_safe(stable_node, next,  in scan_get_next_rmap_item()
2258 				page = get_ksm_page(stable_node,  in scan_get_next_rmap_item()
2620 	struct ksm_stable_node *stable_node;  in rmap_walk_ksm()  local
2632 	stable_node = folio_stable_node(folio);  in rmap_walk_ksm()
2633 	if (!stable_node)  in rmap_walk_ksm()
2636 	hlist_for_each_entry(rmap_item, &stable_node->hlist, hlist) {  in rmap_walk_ksm()
2691 	struct ksm_stable_node *stable_node;  in folio_migrate_ksm()  local
2697 	stable_node = folio_stable_node(folio);  in folio_migrate_ksm()
2698 	if (stable_node) {  in folio_migrate_ksm()
2699 		VM_BUG_ON_FOLIO(stable_node->kpfn != folio_pfn(folio), folio);  in folio_migrate_ksm()
2700 		stable_node->kpfn = folio_pfn(newfolio);  in folio_migrate_ksm()
2724 static bool stable_node_dup_remove_range(struct ksm_stable_node *stable_node,  in stable_node_dup_remove_range()  argument
2728 	if (stable_node->kpfn >= start_pfn &&  in stable_node_dup_remove_range()
2729 	    stable_node->kpfn < end_pfn) {  in stable_node_dup_remove_range()
2734 		remove_node_from_stable_tree(stable_node);  in stable_node_dup_remove_range()
2740 static bool stable_node_chain_remove_range(struct ksm_stable_node *stable_node,  in stable_node_chain_remove_range()  argument
2748 	if (!is_stable_node_chain(stable_node)) {  in stable_node_chain_remove_range()
2749 		VM_BUG_ON(is_stable_node_dup(stable_node));  in stable_node_chain_remove_range()
2750 		return stable_node_dup_remove_range(stable_node, start_pfn,  in stable_node_chain_remove_range()
2755 				  &stable_node->hlist, hlist_dup) {  in stable_node_chain_remove_range()
2759 	if (hlist_empty(&stable_node->hlist)) {  in stable_node_chain_remove_range()
2760 		free_stable_node_chain(stable_node, root);  in stable_node_chain_remove_range()
2769 	struct ksm_stable_node *stable_node, *next;  in ksm_check_stable_tree()  local
2776 			stable_node = rb_entry(node, struct ksm_stable_node, node);  in ksm_check_stable_tree()
2777 			if (stable_node_chain_remove_range(stable_node,  in ksm_check_stable_tree()
2787 	list_for_each_entry_safe(stable_node, next, &migrate_nodes, list) {  in ksm_check_stable_tree()
2788 		if (stable_node->kpfn >= start_pfn &&  in ksm_check_stable_tree()
2789 		    stable_node->kpfn < end_pfn)  in ksm_check_stable_tree()
2790 			remove_node_from_stable_tree(stable_node);  in ksm_check_stable_tree()