Root/lib/rbtree_test.c

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    struct rb_node rb;
12    u32 key;
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(int nr_nodes)
118{
119    struct rb_node *rb;
120    int count = 0;
121    for (rb = rb_first_postorder(&root); rb; rb = rb_next_postorder(rb))
122        count++;
123
124    WARN_ON_ONCE(count != nr_nodes);
125}
126
127static void check(int nr_nodes)
128{
129    struct rb_node *rb;
130    int count = 0, blacks = 0;
131    u32 prev_key = 0;
132
133    for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
134        struct test_node *node = rb_entry(rb, struct test_node, rb);
135        WARN_ON_ONCE(node->key < prev_key);
136        WARN_ON_ONCE(is_red(rb) &&
137                 (!rb_parent(rb) || is_red(rb_parent(rb))));
138        if (!count)
139            blacks = black_path_count(rb);
140        else
141            WARN_ON_ONCE((!rb->rb_left || !rb->rb_right) &&
142                     blacks != black_path_count(rb));
143        prev_key = node->key;
144        count++;
145    }
146
147    WARN_ON_ONCE(count != nr_nodes);
148    WARN_ON_ONCE(count < (1 << black_path_count(rb_last(&root))) - 1);
149
150    check_postorder(nr_nodes);
151}
152
153static void check_augmented(int nr_nodes)
154{
155    struct rb_node *rb;
156
157    check(nr_nodes);
158    for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
159        struct test_node *node = rb_entry(rb, struct test_node, rb);
160        WARN_ON_ONCE(node->augmented != augment_recompute(node));
161    }
162}
163
164static int __init rbtree_test_init(void)
165{
166    int i, j;
167    cycles_t time1, time2, time;
168
169    printk(KERN_ALERT "rbtree testing");
170
171    prandom_seed_state(&rnd, 3141592653589793238ULL);
172    init();
173
174    time1 = get_cycles();
175
176    for (i = 0; i < PERF_LOOPS; i++) {
177        for (j = 0; j < NODES; j++)
178            insert(nodes + j, &root);
179        for (j = 0; j < NODES; j++)
180            erase(nodes + j, &root);
181    }
182
183    time2 = get_cycles();
184    time = time2 - time1;
185
186    time = div_u64(time, PERF_LOOPS);
187    printk(" -> %llu cycles\n", (unsigned long long)time);
188
189    for (i = 0; i < CHECK_LOOPS; i++) {
190        init();
191        for (j = 0; j < NODES; j++) {
192            check(j);
193            insert(nodes + j, &root);
194        }
195        for (j = 0; j < NODES; j++) {
196            check(NODES - j);
197            erase(nodes + j, &root);
198        }
199        check(0);
200    }
201
202    printk(KERN_ALERT "augmented rbtree testing");
203
204    init();
205
206    time1 = get_cycles();
207
208    for (i = 0; i < PERF_LOOPS; i++) {
209        for (j = 0; j < NODES; j++)
210            insert_augmented(nodes + j, &root);
211        for (j = 0; j < NODES; j++)
212            erase_augmented(nodes + j, &root);
213    }
214
215    time2 = get_cycles();
216    time = time2 - time1;
217
218    time = div_u64(time, PERF_LOOPS);
219    printk(" -> %llu cycles\n", (unsigned long long)time);
220
221    for (i = 0; i < CHECK_LOOPS; i++) {
222        init();
223        for (j = 0; j < NODES; j++) {
224            check_augmented(j);
225            insert_augmented(nodes + j, &root);
226        }
227        for (j = 0; j < NODES; j++) {
228            check_augmented(NODES - j);
229            erase_augmented(nodes + j, &root);
230        }
231        check_augmented(0);
232    }
233
234    return -EAGAIN; /* Fail will directly unload the module */
235}
236
237static void __exit rbtree_test_exit(void)
238{
239    printk(KERN_ALERT "test exit\n");
240}
241
242module_init(rbtree_test_init)
243module_exit(rbtree_test_exit)
244
245MODULE_LICENSE("GPL");
246MODULE_AUTHOR("Michel Lespinasse");
247MODULE_DESCRIPTION("Red Black Tree test");
248

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