1#include <linux/module.h>
2#include <linux/rbtree_augmented.h>
3#include <linux/random.h>
4#include <asm/timex.h>
5
6#define NODES       100
7#define PERF_LOOPS  100000
8#define CHECK_LOOPS 100
9
10struct test_node {
11	u32 key;
12	struct rb_node rb;
13
14	/* following fields used for testing augmented rbtree functionality */
15	u32 val;
16	u32 augmented;
17};
18
19static struct rb_root root = RB_ROOT;
20static struct test_node nodes[NODES];
21
22static struct rnd_state rnd;
23
24static void insert(struct test_node *node, struct rb_root *root)
25{
26	struct rb_node **new = &root->rb_node, *parent = NULL;
27	u32 key = node->key;
28
29	while (*new) {
30		parent = *new;
31		if (key < rb_entry(parent, struct test_node, rb)->key)
32			new = &parent->rb_left;
33		else
34			new = &parent->rb_right;
35	}
36
37	rb_link_node(&node->rb, parent, new);
38	rb_insert_color(&node->rb, root);
39}
40
41static inline void erase(struct test_node *node, struct rb_root *root)
42{
43	rb_erase(&node->rb, root);
44}
45
46static inline u32 augment_recompute(struct test_node *node)
47{
48	u32 max = node->val, child_augmented;
49	if (node->rb.rb_left) {
50		child_augmented = rb_entry(node->rb.rb_left, struct test_node,
51					   rb)->augmented;
52		if (max < child_augmented)
53			max = child_augmented;
54	}
55	if (node->rb.rb_right) {
56		child_augmented = rb_entry(node->rb.rb_right, struct test_node,
57					   rb)->augmented;
58		if (max < child_augmented)
59			max = child_augmented;
60	}
61	return max;
62}
63
64RB_DECLARE_CALLBACKS(static, augment_callbacks, struct test_node, rb,
65		     u32, augmented, augment_recompute)
66
67static void insert_augmented(struct test_node *node, struct rb_root *root)
68{
69	struct rb_node **new = &root->rb_node, *rb_parent = NULL;
70	u32 key = node->key;
71	u32 val = node->val;
72	struct test_node *parent;
73
74	while (*new) {
75		rb_parent = *new;
76		parent = rb_entry(rb_parent, struct test_node, rb);
77		if (parent->augmented < val)
78			parent->augmented = val;
79		if (key < parent->key)
80			new = &parent->rb.rb_left;
81		else
82			new = &parent->rb.rb_right;
83	}
84
85	node->augmented = val;
86	rb_link_node(&node->rb, rb_parent, new);
87	rb_insert_augmented(&node->rb, root, &augment_callbacks);
88}
89
90static void erase_augmented(struct test_node *node, struct rb_root *root)
91{
92	rb_erase_augmented(&node->rb, root, &augment_callbacks);
93}
94
95static void init(void)
96{
97	int i;
98	for (i = 0; i < NODES; i++) {
99		nodes[i].key = prandom_u32_state(&rnd);
100		nodes[i].val = prandom_u32_state(&rnd);
101	}
102}
103
104static bool is_red(struct rb_node *rb)
105{
106	return !(rb->__rb_parent_color & 1);
107}
108
109static int black_path_count(struct rb_node *rb)
110{
111	int count;
112	for (count = 0; rb; rb = rb_parent(rb))
113		count += !is_red(rb);
114	return count;
115}
116
117static void check_postorder_foreach(int nr_nodes)
118{
119	struct test_node *cur, *n;
120	int count = 0;
121	rbtree_postorder_for_each_entry_safe(cur, n, &root, rb)
122		count++;
123
124	WARN_ON_ONCE(count != nr_nodes);
125}
126
127static void check_postorder(int nr_nodes)
128{
129	struct rb_node *rb;
130	int count = 0;
131	for (rb = rb_first_postorder(&root); rb; rb = rb_next_postorder(rb))
132		count++;
133
134	WARN_ON_ONCE(count != nr_nodes);
135}
136
137static void check(int nr_nodes)
138{
139	struct rb_node *rb;
140	int count = 0, blacks = 0;
141	u32 prev_key = 0;
142
143	for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
144		struct test_node *node = rb_entry(rb, struct test_node, rb);
145		WARN_ON_ONCE(node->key < prev_key);
146		WARN_ON_ONCE(is_red(rb) &&
147			     (!rb_parent(rb) || is_red(rb_parent(rb))));
148		if (!count)
149			blacks = black_path_count(rb);
150		else
151			WARN_ON_ONCE((!rb->rb_left || !rb->rb_right) &&
152				     blacks != black_path_count(rb));
153		prev_key = node->key;
154		count++;
155	}
156
157	WARN_ON_ONCE(count != nr_nodes);
158	WARN_ON_ONCE(count < (1 << black_path_count(rb_last(&root))) - 1);
159
160	check_postorder(nr_nodes);
161	check_postorder_foreach(nr_nodes);
162}
163
164static void check_augmented(int nr_nodes)
165{
166	struct rb_node *rb;
167
168	check(nr_nodes);
169	for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
170		struct test_node *node = rb_entry(rb, struct test_node, rb);
171		WARN_ON_ONCE(node->augmented != augment_recompute(node));
172	}
173}
174
175static int __init rbtree_test_init(void)
176{
177	int i, j;
178	cycles_t time1, time2, time;
179
180	printk(KERN_ALERT "rbtree testing");
181
182	prandom_seed_state(&rnd, 3141592653589793238ULL);
183	init();
184
185	time1 = get_cycles();
186
187	for (i = 0; i < PERF_LOOPS; i++) {
188		for (j = 0; j < NODES; j++)
189			insert(nodes + j, &root);
190		for (j = 0; j < NODES; j++)
191			erase(nodes + j, &root);
192	}
193
194	time2 = get_cycles();
195	time = time2 - time1;
196
197	time = div_u64(time, PERF_LOOPS);
198	printk(" -> %llu cycles\n", (unsigned long long)time);
199
200	for (i = 0; i < CHECK_LOOPS; i++) {
201		init();
202		for (j = 0; j < NODES; j++) {
203			check(j);
204			insert(nodes + j, &root);
205		}
206		for (j = 0; j < NODES; j++) {
207			check(NODES - j);
208			erase(nodes + j, &root);
209		}
210		check(0);
211	}
212
213	printk(KERN_ALERT "augmented rbtree testing");
214
215	init();
216
217	time1 = get_cycles();
218
219	for (i = 0; i < PERF_LOOPS; i++) {
220		for (j = 0; j < NODES; j++)
221			insert_augmented(nodes + j, &root);
222		for (j = 0; j < NODES; j++)
223			erase_augmented(nodes + j, &root);
224	}
225
226	time2 = get_cycles();
227	time = time2 - time1;
228
229	time = div_u64(time, PERF_LOOPS);
230	printk(" -> %llu cycles\n", (unsigned long long)time);
231
232	for (i = 0; i < CHECK_LOOPS; i++) {
233		init();
234		for (j = 0; j < NODES; j++) {
235			check_augmented(j);
236			insert_augmented(nodes + j, &root);
237		}
238		for (j = 0; j < NODES; j++) {
239			check_augmented(NODES - j);
240			erase_augmented(nodes + j, &root);
241		}
242		check_augmented(0);
243	}
244
245	return -EAGAIN; /* Fail will directly unload the module */
246}
247
248static void __exit rbtree_test_exit(void)
249{
250	printk(KERN_ALERT "test exit\n");
251}
252
253module_init(rbtree_test_init)
254module_exit(rbtree_test_exit)
255
256MODULE_LICENSE("GPL");
257MODULE_AUTHOR("Michel Lespinasse");
258MODULE_DESCRIPTION("Red Black Tree test");
259