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v5.14.15
  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");
v4.17
 
  1#include <linux/module.h>
  2#include <linux/moduleparam.h>
  3#include <linux/rbtree_augmented.h>
  4#include <linux/random.h>
  5#include <linux/slab.h>
  6#include <asm/timex.h>
  7
  8#define __param(type, name, init, msg)		\
  9	static type name = init;		\
 10	module_param(name, type, 0444);		\
 11	MODULE_PARM_DESC(name, msg);
 12
 13__param(int, nnodes, 100, "Number of nodes in the rb-tree");
 14__param(int, perf_loops, 1000, "Number of iterations modifying the rb-tree");
 15__param(int, check_loops, 100, "Number of iterations modifying and verifying the rb-tree");
 16
 17struct test_node {
 18	u32 key;
 19	struct rb_node rb;
 20
 21	/* following fields used for testing augmented rbtree functionality */
 22	u32 val;
 23	u32 augmented;
 24};
 25
 26static struct rb_root_cached root = RB_ROOT_CACHED;
 27static struct test_node *nodes = NULL;
 28
 29static struct rnd_state rnd;
 30
 31static void insert(struct test_node *node, struct rb_root_cached *root)
 32{
 33	struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
 34	u32 key = node->key;
 35
 36	while (*new) {
 37		parent = *new;
 38		if (key < rb_entry(parent, struct test_node, rb)->key)
 39			new = &parent->rb_left;
 40		else
 41			new = &parent->rb_right;
 42	}
 43
 44	rb_link_node(&node->rb, parent, new);
 45	rb_insert_color(&node->rb, &root->rb_root);
 46}
 47
 48static void insert_cached(struct test_node *node, struct rb_root_cached *root)
 49{
 50	struct rb_node **new = &root->rb_root.rb_node, *parent = NULL;
 51	u32 key = node->key;
 52	bool leftmost = true;
 53
 54	while (*new) {
 55		parent = *new;
 56		if (key < rb_entry(parent, struct test_node, rb)->key)
 57			new = &parent->rb_left;
 58		else {
 59			new = &parent->rb_right;
 60			leftmost = false;
 61		}
 62	}
 63
 64	rb_link_node(&node->rb, parent, new);
 65	rb_insert_color_cached(&node->rb, root, leftmost);
 66}
 67
 68static inline void erase(struct test_node *node, struct rb_root_cached *root)
 69{
 70	rb_erase(&node->rb, &root->rb_root);
 71}
 72
 73static inline void erase_cached(struct test_node *node, struct rb_root_cached *root)
 74{
 75	rb_erase_cached(&node->rb, root);
 76}
 77
 78
 79static inline u32 augment_recompute(struct test_node *node)
 80{
 81	u32 max = node->val, child_augmented;
 82	if (node->rb.rb_left) {
 83		child_augmented = rb_entry(node->rb.rb_left, struct test_node,
 84					   rb)->augmented;
 85		if (max < child_augmented)
 86			max = child_augmented;
 87	}
 88	if (node->rb.rb_right) {
 89		child_augmented = rb_entry(node->rb.rb_right, struct test_node,
 90					   rb)->augmented;
 91		if (max < child_augmented)
 92			max = child_augmented;
 93	}
 94	return max;
 95}
 96
 97RB_DECLARE_CALLBACKS(static, augment_callbacks, struct test_node, rb,
 98		     u32, augmented, augment_recompute)
 99
100static void insert_augmented(struct test_node *node,
101			     struct rb_root_cached *root)
102{
103	struct rb_node **new = &root->rb_root.rb_node, *rb_parent = NULL;
104	u32 key = node->key;
105	u32 val = node->val;
106	struct test_node *parent;
107
108	while (*new) {
109		rb_parent = *new;
110		parent = rb_entry(rb_parent, struct test_node, rb);
111		if (parent->augmented < val)
112			parent->augmented = val;
113		if (key < parent->key)
114			new = &parent->rb.rb_left;
115		else
116			new = &parent->rb.rb_right;
117	}
118
119	node->augmented = val;
120	rb_link_node(&node->rb, rb_parent, new);
121	rb_insert_augmented(&node->rb, &root->rb_root, &augment_callbacks);
122}
123
124static void insert_augmented_cached(struct test_node *node,
125				    struct rb_root_cached *root)
126{
127	struct rb_node **new = &root->rb_root.rb_node, *rb_parent = NULL;
128	u32 key = node->key;
129	u32 val = node->val;
130	struct test_node *parent;
131	bool leftmost = true;
132
133	while (*new) {
134		rb_parent = *new;
135		parent = rb_entry(rb_parent, struct test_node, rb);
136		if (parent->augmented < val)
137			parent->augmented = val;
138		if (key < parent->key)
139			new = &parent->rb.rb_left;
140		else {
141			new = &parent->rb.rb_right;
142			leftmost = false;
143		}
144	}
145
146	node->augmented = val;
147	rb_link_node(&node->rb, rb_parent, new);
148	rb_insert_augmented_cached(&node->rb, root,
149				   leftmost, &augment_callbacks);
150}
151
152
153static void erase_augmented(struct test_node *node, struct rb_root_cached *root)
154{
155	rb_erase_augmented(&node->rb, &root->rb_root, &augment_callbacks);
156}
157
158static void erase_augmented_cached(struct test_node *node,
159				   struct rb_root_cached *root)
160{
161	rb_erase_augmented_cached(&node->rb, root, &augment_callbacks);
162}
163
164static void init(void)
165{
166	int i;
167	for (i = 0; i < nnodes; i++) {
168		nodes[i].key = prandom_u32_state(&rnd);
169		nodes[i].val = prandom_u32_state(&rnd);
170	}
171}
172
173static bool is_red(struct rb_node *rb)
174{
175	return !(rb->__rb_parent_color & 1);
176}
177
178static int black_path_count(struct rb_node *rb)
179{
180	int count;
181	for (count = 0; rb; rb = rb_parent(rb))
182		count += !is_red(rb);
183	return count;
184}
185
186static void check_postorder_foreach(int nr_nodes)
187{
188	struct test_node *cur, *n;
189	int count = 0;
190	rbtree_postorder_for_each_entry_safe(cur, n, &root.rb_root, rb)
191		count++;
192
193	WARN_ON_ONCE(count != nr_nodes);
194}
195
196static void check_postorder(int nr_nodes)
197{
198	struct rb_node *rb;
199	int count = 0;
200	for (rb = rb_first_postorder(&root.rb_root); rb; rb = rb_next_postorder(rb))
201		count++;
202
203	WARN_ON_ONCE(count != nr_nodes);
204}
205
206static void check(int nr_nodes)
207{
208	struct rb_node *rb;
209	int count = 0, blacks = 0;
210	u32 prev_key = 0;
211
212	for (rb = rb_first(&root.rb_root); rb; rb = rb_next(rb)) {
213		struct test_node *node = rb_entry(rb, struct test_node, rb);
214		WARN_ON_ONCE(node->key < prev_key);
215		WARN_ON_ONCE(is_red(rb) &&
216			     (!rb_parent(rb) || is_red(rb_parent(rb))));
217		if (!count)
218			blacks = black_path_count(rb);
219		else
220			WARN_ON_ONCE((!rb->rb_left || !rb->rb_right) &&
221				     blacks != black_path_count(rb));
222		prev_key = node->key;
223		count++;
224	}
225
226	WARN_ON_ONCE(count != nr_nodes);
227	WARN_ON_ONCE(count < (1 << black_path_count(rb_last(&root.rb_root))) - 1);
228
229	check_postorder(nr_nodes);
230	check_postorder_foreach(nr_nodes);
231}
232
233static void check_augmented(int nr_nodes)
234{
235	struct rb_node *rb;
236
237	check(nr_nodes);
238	for (rb = rb_first(&root.rb_root); rb; rb = rb_next(rb)) {
239		struct test_node *node = rb_entry(rb, struct test_node, rb);
240		WARN_ON_ONCE(node->augmented != augment_recompute(node));
 
 
 
 
 
 
 
 
 
 
 
 
 
241	}
242}
243
244static int __init rbtree_test_init(void)
245{
246	int i, j;
247	cycles_t time1, time2, time;
248	struct rb_node *node;
249
250	nodes = kmalloc(nnodes * sizeof(*nodes), GFP_KERNEL);
251	if (!nodes)
252		return -ENOMEM;
253
254	printk(KERN_ALERT "rbtree testing");
255
256	prandom_seed_state(&rnd, 3141592653589793238ULL);
257	init();
258
259	time1 = get_cycles();
260
261	for (i = 0; i < perf_loops; i++) {
262		for (j = 0; j < nnodes; j++)
263			insert(nodes + j, &root);
264		for (j = 0; j < nnodes; j++)
265			erase(nodes + j, &root);
266	}
267
268	time2 = get_cycles();
269	time = time2 - time1;
270
271	time = div_u64(time, perf_loops);
272	printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n",
273	       (unsigned long long)time);
274
275	time1 = get_cycles();
276
277	for (i = 0; i < perf_loops; i++) {
278		for (j = 0; j < nnodes; j++)
279			insert_cached(nodes + j, &root);
280		for (j = 0; j < nnodes; j++)
281			erase_cached(nodes + j, &root);
282	}
283
284	time2 = get_cycles();
285	time = time2 - time1;
286
287	time = div_u64(time, perf_loops);
288	printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n",
289	       (unsigned long long)time);
290
291	for (i = 0; i < nnodes; i++)
292		insert(nodes + i, &root);
293
294	time1 = get_cycles();
295
296	for (i = 0; i < perf_loops; i++) {
297		for (node = rb_first(&root.rb_root); node; node = rb_next(node))
298			;
299	}
300
301	time2 = get_cycles();
302	time = time2 - time1;
303
304	time = div_u64(time, perf_loops);
305	printk(" -> test 3 (latency of inorder traversal): %llu cycles\n",
306	       (unsigned long long)time);
307
308	time1 = get_cycles();
309
310	for (i = 0; i < perf_loops; i++)
311		node = rb_first(&root.rb_root);
312
313	time2 = get_cycles();
314	time = time2 - time1;
315
316	time = div_u64(time, perf_loops);
317	printk(" -> test 4 (latency to fetch first node)\n");
318	printk("        non-cached: %llu cycles\n", (unsigned long long)time);
319
320	time1 = get_cycles();
321
322	for (i = 0; i < perf_loops; i++)
323		node = rb_first_cached(&root);
324
325	time2 = get_cycles();
326	time = time2 - time1;
327
328	time = div_u64(time, perf_loops);
329	printk("        cached: %llu cycles\n", (unsigned long long)time);
330
331	for (i = 0; i < nnodes; i++)
332		erase(nodes + i, &root);
333
334	/* run checks */
335	for (i = 0; i < check_loops; i++) {
336		init();
337		for (j = 0; j < nnodes; j++) {
338			check(j);
339			insert(nodes + j, &root);
340		}
341		for (j = 0; j < nnodes; j++) {
342			check(nnodes - j);
343			erase(nodes + j, &root);
344		}
345		check(0);
346	}
347
348	printk(KERN_ALERT "augmented rbtree testing");
349
350	init();
351
352	time1 = get_cycles();
353
354	for (i = 0; i < perf_loops; i++) {
355		for (j = 0; j < nnodes; j++)
356			insert_augmented(nodes + j, &root);
357		for (j = 0; j < nnodes; j++)
358			erase_augmented(nodes + j, &root);
359	}
360
361	time2 = get_cycles();
362	time = time2 - time1;
363
364	time = div_u64(time, perf_loops);
365	printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n", (unsigned long long)time);
366
367	time1 = get_cycles();
368
369	for (i = 0; i < perf_loops; i++) {
370		for (j = 0; j < nnodes; j++)
371			insert_augmented_cached(nodes + j, &root);
372		for (j = 0; j < nnodes; j++)
373			erase_augmented_cached(nodes + j, &root);
374	}
375
376	time2 = get_cycles();
377	time = time2 - time1;
378
379	time = div_u64(time, perf_loops);
380	printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n", (unsigned long long)time);
381
382	for (i = 0; i < check_loops; i++) {
383		init();
384		for (j = 0; j < nnodes; j++) {
385			check_augmented(j);
386			insert_augmented(nodes + j, &root);
387		}
388		for (j = 0; j < nnodes; j++) {
389			check_augmented(nnodes - j);
390			erase_augmented(nodes + j, &root);
391		}
392		check_augmented(0);
393	}
394
395	kfree(nodes);
396
397	return -EAGAIN; /* Fail will directly unload the module */
398}
399
400static void __exit rbtree_test_exit(void)
401{
402	printk(KERN_ALERT "test exit\n");
403}
404
405module_init(rbtree_test_init)
406module_exit(rbtree_test_exit)
407
408MODULE_LICENSE("GPL");
409MODULE_AUTHOR("Michel Lespinasse");
410MODULE_DESCRIPTION("Red Black Tree test");