1 // SPDX-License-Identifier: GPL-2.0-only
2 #include <linux/module.h>
3 #include <linux/moduleparam.h>
4 #include <linux/rbtree_augmented.h>
5 #include <linux/random.h>
6 #include <linux/slab.h>
7 #include <asm/timex.h>
8
9 #define __param(type, name, init, msg) \
10 static type name = init; \
11 module_param(name, type, 0444); \
12 MODULE_PARM_DESC(name, msg);
13
14 __param(int, nnodes, 100, "Number of nodes in the rb-tree");
15 __param(int, perf_loops, 1000, "Number of iterations modifying the rb-tree");
16 __param(int, check_loops, 100, "Number of iterations modifying and verifying the rb-tree");
17
18 struct test_node {
19 u32 key;
20 struct rb_node rb;
21
22 /* following fields used for testing augmented rbtree functionality */
23 u32 val;
24 u32 augmented;
25 };
26
27 static struct rb_root_cached root = RB_ROOT_CACHED;
28 static struct test_node *nodes = NULL;
29
30 static struct rnd_state rnd;
31
32 static void insert(struct test_node *node, struct rb_root_cached *root)
33 {
34 struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
35 u32 key = node->key;
36
37 while (*new) {
38 parent = *new;
39 if (key < rb_entry(parent, struct test_node, rb)->key)
40 new = &parent->rb_left;
41 else
42 new = &parent->rb_right;
43 }
44
45 rb_link_node(&node->rb, parent, new);
46 rb_insert_color(&node->rb, &root->rb_root);
47 }
48
49 static void insert_cached(struct test_node *node, struct rb_root_cached *root)
50 {
51 struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
52 u32 key = node->key;
53 bool leftmost = true;
54
55 while (*new) {
56 parent = *new;
57 if (key < rb_entry(parent, struct test_node, rb)->key)
58 new = &parent->rb_left;
59 else {
60 new = &parent->rb_right;
61 leftmost = false;
62 }
63 }
64
65 rb_link_node(&node->rb, parent, new);
66 rb_insert_color_cached(&node->rb, root, leftmost);
67 }
68
69 static inline void erase(struct test_node *node, struct rb_root_cached *root)
70 {
71 rb_erase(&node->rb, &root->rb_root);
72 }
73
74 static inline void erase_cached(struct test_node *node, struct rb_root_cached *root)
75 {
76 rb_erase_cached(&node->rb, root);
77 }
78
79
80 #define NODE_VAL(node) ((node)->val)
81
82 RB_DECLARE_CALLBACKS_MAX(static, augment_callbacks,
83 struct test_node, rb, u32, augmented, NODE_VAL)
84
85 static void insert_augmented(struct test_node *node,
86 struct rb_root_cached *root)
87 {
88 struct rb_node **new = &root->rb_root.rb_node, *rb_parent = NULL;
89 u32 key = node->key;
90 u32 val = node->val;
91 struct test_node *parent;
92
93 while (*new) {
94 rb_parent = *new;
95 parent = rb_entry(rb_parent, struct test_node, rb);
96 if (parent->augmented < val)
97 parent->augmented = val;
98 if (key < parent->key)
99 new = &parent->rb.rb_left;
100 else
101 new = &parent->rb.rb_right;
102 }
103
104 node->augmented = val;
105 rb_link_node(&node->rb, rb_parent, new);
106 rb_insert_augmented(&node->rb, &root->rb_root, &augment_callbacks);
107 }
108
109 static void insert_augmented_cached(struct test_node *node,
110 struct rb_root_cached *root)
111 {
112 struct rb_node **new = &root->rb_root.rb_node, *rb_parent = NULL;
113 u32 key = node->key;
114 u32 val = node->val;
115 struct test_node *parent;
116 bool leftmost = true;
117
118 while (*new) {
119 rb_parent = *new;
120 parent = rb_entry(rb_parent, struct test_node, rb);
121 if (parent->augmented < val)
122 parent->augmented = val;
123 if (key < parent->key)
124 new = &parent->rb.rb_left;
125 else {
126 new = &parent->rb.rb_right;
127 leftmost = false;
128 }
129 }
130
131 node->augmented = val;
132 rb_link_node(&node->rb, rb_parent, new);
133 rb_insert_augmented_cached(&node->rb, root,
134 leftmost, &augment_callbacks);
135 }
136
137
138 static void erase_augmented(struct test_node *node, struct rb_root_cached *root)
139 {
140 rb_erase_augmented(&node->rb, &root->rb_root, &augment_callbacks);
141 }
142
143 static void erase_augmented_cached(struct test_node *node,
144 struct rb_root_cached *root)
145 {
146 rb_erase_augmented_cached(&node->rb, root, &augment_callbacks);
147 }
148
149 static void init(void)
150 {
151 int i;
152 for (i = 0; i < nnodes; i++) {
153 nodes[i].key = prandom_u32_state(&rnd);
154 nodes[i].val = prandom_u32_state(&rnd);
155 }
156 }
157
158 static bool is_red(struct rb_node *rb)
159 {
160 return !(rb->__rb_parent_color & 1);
161 }
162
163 static int black_path_count(struct rb_node *rb)
164 {
165 int count;
166 for (count = 0; rb; rb = rb_parent(rb))
167 count += !is_red(rb);
168 return count;
169 }
170
171 static void check_postorder_foreach(int nr_nodes)
172 {
173 struct test_node *cur, *n;
174 int count = 0;
175 rbtree_postorder_for_each_entry_safe(cur, n, &root.rb_root, rb)
176 count++;
177
178 WARN_ON_ONCE(count != nr_nodes);
179 }
180
181 static void check_postorder(int nr_nodes)
182 {
183 struct rb_node *rb;
184 int count = 0;
185 for (rb = rb_first_postorder(&root.rb_root); rb; rb = rb_next_postorder(rb))
186 count++;
187
188 WARN_ON_ONCE(count != nr_nodes);
189 }
190
191 static void check(int nr_nodes)
192 {
193 struct rb_node *rb;
194 int count = 0, blacks = 0;
195 u32 prev_key = 0;
196
197 for (rb = rb_first(&root.rb_root); rb; rb = rb_next(rb)) {
198 struct test_node *node = rb_entry(rb, struct test_node, rb);
199 WARN_ON_ONCE(node->key < prev_key);
200 WARN_ON_ONCE(is_red(rb) &&
201 (!rb_parent(rb) || is_red(rb_parent(rb))));
202 if (!count)
203 blacks = black_path_count(rb);
204 else
205 WARN_ON_ONCE((!rb->rb_left || !rb->rb_right) &&
206 blacks != black_path_count(rb));
207 prev_key = node->key;
208 count++;
209 }
210
211 WARN_ON_ONCE(count != nr_nodes);
212 WARN_ON_ONCE(count < (1 << black_path_count(rb_last(&root.rb_root))) - 1);
213
214 check_postorder(nr_nodes);
215 check_postorder_foreach(nr_nodes);
216 }
217
218 static void check_augmented(int nr_nodes)
219 {
220 struct rb_node *rb;
221
222 check(nr_nodes);
223 for (rb = rb_first(&root.rb_root); rb; rb = rb_next(rb)) {
224 struct test_node *node = rb_entry(rb, struct test_node, rb);
225 u32 subtree, max = node->val;
226 if (node->rb.rb_left) {
227 subtree = rb_entry(node->rb.rb_left, struct test_node,
228 rb)->augmented;
229 if (max < subtree)
230 max = subtree;
231 }
232 if (node->rb.rb_right) {
233 subtree = rb_entry(node->rb.rb_right, struct test_node,
234 rb)->augmented;
235 if (max < subtree)
236 max = subtree;
237 }
238 WARN_ON_ONCE(node->augmented != max);
239 }
240 }
241
242 static int __init rbtree_test_init(void)
243 {
244 int i, j;
245 cycles_t time1, time2, time;
246 struct rb_node *node;
247
248 nodes = kmalloc_array(nnodes, sizeof(*nodes), GFP_KERNEL);
249 if (!nodes)
250 return -ENOMEM;
251
252 printk(KERN_ALERT "rbtree testing");
253
254 prandom_seed_state(&rnd, 3141592653589793238ULL);
255 init();
256
257 time1 = get_cycles();
258
259 for (i = 0; i < perf_loops; i++) {
260 for (j = 0; j < nnodes; j++)
261 insert(nodes + j, &root);
262 for (j = 0; j < nnodes; j++)
263 erase(nodes + j, &root);
264 }
265
266 time2 = get_cycles();
267 time = time2 - time1;
268
269 time = div_u64(time, perf_loops);
270 printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n",
271 (unsigned long long)time);
272
273 time1 = get_cycles();
274
275 for (i = 0; i < perf_loops; i++) {
276 for (j = 0; j < nnodes; j++)
277 insert_cached(nodes + j, &root);
278 for (j = 0; j < nnodes; j++)
279 erase_cached(nodes + j, &root);
280 }
281
282 time2 = get_cycles();
283 time = time2 - time1;
284
285 time = div_u64(time, perf_loops);
286 printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n",
287 (unsigned long long)time);
288
289 for (i = 0; i < nnodes; i++)
290 insert(nodes + i, &root);
291
292 time1 = get_cycles();
293
294 for (i = 0; i < perf_loops; i++) {
295 for (node = rb_first(&root.rb_root); node; node = rb_next(node))
296 ;
297 }
298
299 time2 = get_cycles();
300 time = time2 - time1;
301
302 time = div_u64(time, perf_loops);
303 printk(" -> test 3 (latency of inorder traversal): %llu cycles\n",
304 (unsigned long long)time);
305
306 time1 = get_cycles();
307
308 for (i = 0; i < perf_loops; i++)
309 node = rb_first(&root.rb_root);
310
311 time2 = get_cycles();
312 time = time2 - time1;
313
314 time = div_u64(time, perf_loops);
315 printk(" -> test 4 (latency to fetch first node)\n");
316 printk(" non-cached: %llu cycles\n", (unsigned long long)time);
317
318 time1 = get_cycles();
319
320 for (i = 0; i < perf_loops; i++)
321 node = rb_first_cached(&root);
322
323 time2 = get_cycles();
324 time = time2 - time1;
325
326 time = div_u64(time, perf_loops);
327 printk(" cached: %llu cycles\n", (unsigned long long)time);
328
329 for (i = 0; i < nnodes; i++)
330 erase(nodes + i, &root);
331
332 /* run checks */
333 for (i = 0; i < check_loops; i++) {
334 init();
335 for (j = 0; j < nnodes; j++) {
336 check(j);
337 insert(nodes + j, &root);
338 }
339 for (j = 0; j < nnodes; j++) {
340 check(nnodes - j);
341 erase(nodes + j, &root);
342 }
343 check(0);
344 }
345
346 printk(KERN_ALERT "augmented rbtree testing");
347
348 init();
349
350 time1 = get_cycles();
351
352 for (i = 0; i < perf_loops; i++) {
353 for (j = 0; j < nnodes; j++)
354 insert_augmented(nodes + j, &root);
355 for (j = 0; j < nnodes; j++)
356 erase_augmented(nodes + j, &root);
357 }
358
359 time2 = get_cycles();
360 time = time2 - time1;
361
362 time = div_u64(time, perf_loops);
363 printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n", (unsigned long long)time);
364
365 time1 = get_cycles();
366
367 for (i = 0; i < perf_loops; i++) {
368 for (j = 0; j < nnodes; j++)
369 insert_augmented_cached(nodes + j, &root);
370 for (j = 0; j < nnodes; j++)
371 erase_augmented_cached(nodes + j, &root);
372 }
373
374 time2 = get_cycles();
375 time = time2 - time1;
376
377 time = div_u64(time, perf_loops);
378 printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n", (unsigned long long)time);
379
380 for (i = 0; i < check_loops; i++) {
381 init();
382 for (j = 0; j < nnodes; j++) {
383 check_augmented(j);
384 insert_augmented(nodes + j, &root);
385 }
386 for (j = 0; j < nnodes; j++) {
387 check_augmented(nnodes - j);
388 erase_augmented(nodes + j, &root);
389 }
390 check_augmented(0);
391 }
392
393 kfree(nodes);
394
395 return -EAGAIN; /* Fail will directly unload the module */
396 }
397
398 static void __exit rbtree_test_exit(void)
399 {
400 printk(KERN_ALERT "test exit\n");
401 }
402
403 module_init(rbtree_test_init)
404 module_exit(rbtree_test_exit)
405
406 MODULE_LICENSE("GPL");
407 MODULE_AUTHOR("Michel Lespinasse");
408 MODULE_DESCRIPTION("Red Black Tree test");
409
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