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 = prandom32(&rnd);
 100                 nodes[i].val = prandom32(&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;
 121         int blacks;
 122         u32 prev_key = 0;
 123
 124         for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
 125                 struct test_node *node = rb_entry(rb, struct test_node, rb);
 126                 WARN_ON_ONCE(node->key < prev_key);
 127                 WARN_ON_ONCE(is_red(rb) &&
 128                              (!rb_parent(rb) || is_red(rb_parent(rb))));
 129                 if (!count)
 130                         blacks = black_path_count(rb);
 131                 else
 132                         WARN_ON_ONCE((!rb->rb_left || !rb->rb_right) &&
 133                                      blacks != black_path_count(rb));
 134                 prev_key = node->key;
 135                 count++;
 136         }
 137         WARN_ON_ONCE(count != nr_nodes);
 138 }
 139
 140 static void check_augmented(int nr_nodes)
 141 {
 142         struct rb_node *rb;
 143
 144         check(nr_nodes);
 145         for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
 146                 struct test_node *node = rb_entry(rb, struct test_node, rb);
 147                 WARN_ON_ONCE(node->augmented != augment_recompute(node));
 148         }
 149 }
 150
 151 static int rbtree_test_init(void)
 152 {
 153         int i, j;
 154         cycles_t time1, time2, time;
 155
 156         printk(KERN_ALERT "rbtree testing");
 157
 158         prandom32_seed(&rnd, 3141592653589793238ULL);
 159         init();
 160
 161         time1 = get_cycles();
 162
 163         for (i = 0; i < PERF_LOOPS; i++) {
 164                 for (j = 0; j < NODES; j++)
 165                         insert(nodes + j, &root);
 166                 for (j = 0; j < NODES; j++)
 167                         erase(nodes + j, &root);
 168         }
 169
 170         time2 = get_cycles();
 171         time = time2 - time1;
 172
 173         time = div_u64(time, PERF_LOOPS);
 174         printk(" -> %llu cycles\n", (unsigned long long)time);
 175
 176         for (i = 0; i < CHECK_LOOPS; i++) {
 177                 init();
 178                 for (j = 0; j < NODES; j++) {
 179                         check(j);
 180                         insert(nodes + j, &root);
 181                 }
 182                 for (j = 0; j < NODES; j++) {
 183                         check(NODES - j);
 184                         erase(nodes + j, &root);
 185                 }
 186                 check(0);
 187         }
 188
 189         printk(KERN_ALERT "augmented rbtree testing");
 190
 191         init();
 192
 193         time1 = get_cycles();
 194
 195         for (i = 0; i < PERF_LOOPS; i++) {
 196                 for (j = 0; j < NODES; j++)
 197                         insert_augmented(nodes + j, &root);
 198                 for (j = 0; j < NODES; j++)
 199                         erase_augmented(nodes + j, &root);
 200         }
 201
 202         time2 = get_cycles();
 203         time = time2 - time1;
 204
 205         time = div_u64(time, PERF_LOOPS);
 206         printk(" -> %llu cycles\n", (unsigned long long)time);
 207
 208         for (i = 0; i < CHECK_LOOPS; i++) {
 209                 init();
 210                 for (j = 0; j < NODES; j++) {
 211                         check_augmented(j);
 212                         insert_augmented(nodes + j, &root);
 213                 }
 214                 for (j = 0; j < NODES; j++) {
 215                         check_augmented(NODES - j);
 216                         erase_augmented(nodes + j, &root);
 217                 }
 218                 check_augmented(0);
 219         }
 220
 221         return -EAGAIN; /* Fail will directly unload the module */
 222 }
 223
 224 static void rbtree_test_exit(void)
 225 {
 226         printk(KERN_ALERT "test exit\n");
 227 }
 228
 229 module_init(rbtree_test_init)
 230 module_exit(rbtree_test_exit)
 231
 232 MODULE_LICENSE("GPL");
 233 MODULE_AUTHOR("Michel Lespinasse");
 234 MODULE_DESCRIPTION("Red Black Tree test");