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
  10 struct 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
  19 static struct rb_root root = RB_ROOT;
  20 static struct test_node nodes[NODES];
  21
  22 static struct rnd_state rnd;
  23
  24 static 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
  41 static inline void erase(struct test_node *node, struct rb_root *root)
  42 {
  43         rb_erase(&node->rb, root);
  44 }
  45
  46 static 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
  64 RB_DECLARE_CALLBACKS(static, augment_callbacks, struct test_node, rb,
  65                      u32, augmented, augment_recompute)
  66
  67 static 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
  90 static void erase_augmented(struct test_node *node, struct rb_root *root)
  91 {
  92         rb_erase_augmented(&node->rb, root, &augment_callbacks);
  93 }
  94
  95 static 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
 104 static bool is_red(struct rb_node *rb)
 105 {
 106         return !(rb->__rb_parent_color & 1);
 107 }
 108
 109 static 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
 117 static void check(int nr_nodes)
 118 {
 119         struct rb_node *rb;
 120         int count = 0, blacks = 0;
 121         u32 prev_key = 0;
 122
 123         for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
 124                 struct test_node *node = rb_entry(rb, struct test_node, rb);
 125                 WARN_ON_ONCE(node->key < prev_key);
 126                 WARN_ON_ONCE(is_red(rb) &&
 127                              (!rb_parent(rb) || is_red(rb_parent(rb))));
 128                 if (!count)
 129                         blacks = black_path_count(rb);
 130                 else
 131                         WARN_ON_ONCE((!rb->rb_left || !rb->rb_right) &&
 132                                      blacks != black_path_count(rb));
 133                 prev_key = node->key;
 134                 count++;
 135         }
 136
 137         WARN_ON_ONCE(count != nr_nodes);
 138         WARN_ON_ONCE(count < (1 << black_path_count(rb_last(&root))) - 1);
 139 }
 140
 141 static void check_augmented(int nr_nodes)
 142 {
 143         struct rb_node *rb;
 144
 145         check(nr_nodes);
 146         for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
 147                 struct test_node *node = rb_entry(rb, struct test_node, rb);
 148                 WARN_ON_ONCE(node->augmented != augment_recompute(node));
 149         }
 150 }
 151
 152 static int __init rbtree_test_init(void)
 153 {
 154         int i, j;
 155         cycles_t time1, time2, time;
 156
 157         printk(KERN_ALERT "rbtree testing");
 158
 159         prandom_seed_state(&rnd, 3141592653589793238ULL);
 160         init();
 161
 162         time1 = get_cycles();
 163
 164         for (i = 0; i < PERF_LOOPS; i++) {
 165                 for (j = 0; j < NODES; j++)
 166                         insert(nodes + j, &root);
 167                 for (j = 0; j < NODES; j++)
 168                         erase(nodes + j, &root);
 169         }
 170
 171         time2 = get_cycles();
 172         time = time2 - time1;
 173
 174         time = div_u64(time, PERF_LOOPS);
 175         printk(" -> %llu cycles\n", (unsigned long long)time);
 176
 177         for (i = 0; i < CHECK_LOOPS; i++) {
 178                 init();
 179                 for (j = 0; j < NODES; j++) {
 180                         check(j);
 181                         insert(nodes + j, &root);
 182                 }
 183                 for (j = 0; j < NODES; j++) {
 184                         check(NODES - j);
 185                         erase(nodes + j, &root);
 186                 }
 187                 check(0);
 188         }
 189
 190         printk(KERN_ALERT "augmented rbtree testing");
 191
 192         init();
 193
 194         time1 = get_cycles();
 195
 196         for (i = 0; i < PERF_LOOPS; i++) {
 197                 for (j = 0; j < NODES; j++)
 198                         insert_augmented(nodes + j, &root);
 199                 for (j = 0; j < NODES; j++)
 200                         erase_augmented(nodes + j, &root);
 201         }
 202
 203         time2 = get_cycles();
 204         time = time2 - time1;
 205
 206         time = div_u64(time, PERF_LOOPS);
 207         printk(" -> %llu cycles\n", (unsigned long long)time);
 208
 209         for (i = 0; i < CHECK_LOOPS; i++) {
 210                 init();
 211                 for (j = 0; j < NODES; j++) {
 212                         check_augmented(j);
 213                         insert_augmented(nodes + j, &root);
 214                 }
 215                 for (j = 0; j < NODES; j++) {
 216                         check_augmented(NODES - j);
 217                         erase_augmented(nodes + j, &root);
 218                 }
 219                 check_augmented(0);
 220         }
 221
 222         return -EAGAIN; /* Fail will directly unload the module */
 223 }
 224
 225 static void __exit rbtree_test_exit(void)
 226 {
 227         printk(KERN_ALERT "test exit\n");
 228 }
 229
 230 module_init(rbtree_test_init)
 231 module_exit(rbtree_test_exit)
 232
 233 MODULE_LICENSE("GPL");
 234 MODULE_AUTHOR("Michel Lespinasse");
 235 MODULE_DESCRIPTION("Red Black Tree test");