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
18struct 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
27static struct rb_root_cached root = RB_ROOT_CACHED;
28static struct test_node *nodes = NULL;
29
30static struct rnd_state rnd;
31
32static 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
49static 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
69static inline void erase(struct test_node *node, struct rb_root_cached *root)
70{
71	rb_erase(&node->rb, &root->rb_root);
72}
73
74static 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
82RB_DECLARE_CALLBACKS_MAX(static, augment_callbacks,
83			 struct test_node, rb, u32, augmented, NODE_VAL)
84
85static 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
109static 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
138static 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
143static 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
149static 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
158static bool is_red(struct rb_node *rb)
159{
160	return !(rb->__rb_parent_color & 1);
161}
162
163static 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
171static 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
181static 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
191static 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
218static 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
242static 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
398static void __exit rbtree_test_exit(void)
399{
400	printk(KERN_ALERT "test exit\n");
401}
402
403module_init(rbtree_test_init)
404module_exit(rbtree_test_exit)
405
406MODULE_LICENSE("GPL");
407MODULE_AUTHOR("Michel Lespinasse");
408MODULE_DESCRIPTION("Red Black Tree test");
409