lib/rbtree_test.c

   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
  17 struct 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
  26 static struct rb_root root = RB_ROOT;
  27 static struct test_node *nodes = NULL;
  28
  29 static struct rnd_state rnd;
  30
  31 static void insert(struct test_node *node, struct rb_root *root)
  32 {
  33         struct rb_node **new = &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);
  46 }
  47
  48 static inline void erase(struct test_node *node, struct rb_root *root)
  49 {
  50         rb_erase(&node->rb, root);
  51 }
  52
  53 static inline u32 augment_recompute(struct test_node *node)
  54 {
  55         u32 max = node->val, child_augmented;
  56         if (node->rb.rb_left) {
  57                 child_augmented = rb_entry(node->rb.rb_left, struct test_node,
  58                                            rb)->augmented;
  59                 if (max < child_augmented)
  60                         max = child_augmented;
  61         }
  62         if (node->rb.rb_right) {
  63                 child_augmented = rb_entry(node->rb.rb_right, struct test_node,
  64                                            rb)->augmented;
  65                 if (max < child_augmented)
  66                         max = child_augmented;
  67         }
  68         return max;
  69 }
  70
  71 RB_DECLARE_CALLBACKS(static, augment_callbacks, struct test_node, rb,
  72                      u32, augmented, augment_recompute)
  73
  74 static void insert_augmented(struct test_node *node, struct rb_root *root)
  75 {
  76         struct rb_node **new = &root->rb_node, *rb_parent = NULL;
  77         u32 key = node->key;
  78         u32 val = node->val;
  79         struct test_node *parent;
  80
  81         while (*new) {
  82                 rb_parent = *new;
  83                 parent = rb_entry(rb_parent, struct test_node, rb);
  84                 if (parent->augmented < val)
  85                         parent->augmented = val;
  86                 if (key < parent->key)
  87                         new = &parent->rb.rb_left;
  88                 else
  89                         new = &parent->rb.rb_right;
  90         }
  91
  92         node->augmented = val;
  93         rb_link_node(&node->rb, rb_parent, new);
  94         rb_insert_augmented(&node->rb, root, &augment_callbacks);
  95 }
  96
  97 static void erase_augmented(struct test_node *node, struct rb_root *root)
  98 {
  99         rb_erase_augmented(&node->rb, root, &augment_callbacks);
 100 }
 101
 102 static void init(void)
 103 {
 104         int i;
 105         for (i = 0; i < nnodes; i++) {
 106                 nodes[i].key = prandom_u32_state(&rnd);
 107                 nodes[i].val = prandom_u32_state(&rnd);
 108         }
 109 }
 110
 111 static bool is_red(struct rb_node *rb)
 112 {
 113         return !(rb->__rb_parent_color & 1);
 114 }
 115
 116 static int black_path_count(struct rb_node *rb)
 117 {
 118         int count;
 119         for (count = 0; rb; rb = rb_parent(rb))
 120                 count += !is_red(rb);
 121         return count;
 122 }
 123
 124 static void check_postorder_foreach(int nr_nodes)
 125 {
 126         struct test_node *cur, *n;
 127         int count = 0;
 128         rbtree_postorder_for_each_entry_safe(cur, n, &root, rb)
 129                 count++;
 130
 131         WARN_ON_ONCE(count != nr_nodes);
 132 }
 133
 134 static void check_postorder(int nr_nodes)
 135 {
 136         struct rb_node *rb;
 137         int count = 0;
 138         for (rb = rb_first_postorder(&root); rb; rb = rb_next_postorder(rb))
 139                 count++;
 140
 141         WARN_ON_ONCE(count != nr_nodes);
 142 }
 143
 144 static void check(int nr_nodes)
 145 {
 146         struct rb_node *rb;
 147         int count = 0, blacks = 0;
 148         u32 prev_key = 0;
 149
 150         for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
 151                 struct test_node *node = rb_entry(rb, struct test_node, rb);
 152                 WARN_ON_ONCE(node->key < prev_key);
 153                 WARN_ON_ONCE(is_red(rb) &&
 154                              (!rb_parent(rb) || is_red(rb_parent(rb))));
 155                 if (!count)
 156                         blacks = black_path_count(rb);
 157                 else
 158                         WARN_ON_ONCE((!rb->rb_left || !rb->rb_right) &&
 159                                      blacks != black_path_count(rb));
 160                 prev_key = node->key;
 161                 count++;
 162         }
 163
 164         WARN_ON_ONCE(count != nr_nodes);
 165         WARN_ON_ONCE(count < (1 << black_path_count(rb_last(&root))) - 1);
 166
 167         check_postorder(nr_nodes);
 168         check_postorder_foreach(nr_nodes);
 169 }
 170
 171 static void check_augmented(int nr_nodes)
 172 {
 173         struct rb_node *rb;
 174
 175         check(nr_nodes);
 176         for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
 177                 struct test_node *node = rb_entry(rb, struct test_node, rb);
 178                 WARN_ON_ONCE(node->augmented != augment_recompute(node));
 179         }
 180 }
 181
 182 static int __init rbtree_test_init(void)
 183 {
 184         int i, j;
 185         cycles_t time1, time2, time;
 186
 187         nodes = kmalloc(nnodes * sizeof(*nodes), GFP_KERNEL);
 188         if (!nodes)
 189                 return -ENOMEM;
 190
 191         printk(KERN_ALERT "rbtree testing");
 192
 193         prandom_seed_state(&rnd, 3141592653589793238ULL);
 194         init();
 195
 196         time1 = get_cycles();
 197
 198         for (i = 0; i < perf_loops; i++) {
 199                 for (j = 0; j < nnodes; j++)
 200                         insert(nodes + j, &root);
 201                 for (j = 0; j < nnodes; j++)
 202                         erase(nodes + j, &root);
 203         }
 204
 205         time2 = get_cycles();
 206         time = time2 - time1;
 207
 208         time = div_u64(time, perf_loops);
 209         printk(" -> %llu cycles\n", (unsigned long long)time);
 210
 211         for (i = 0; i < check_loops; i++) {
 212                 init();
 213                 for (j = 0; j < nnodes; j++) {
 214                         check(j);
 215                         insert(nodes + j, &root);
 216                 }
 217                 for (j = 0; j < nnodes; j++) {
 218                         check(nnodes - j);
 219                         erase(nodes + j, &root);
 220                 }
 221                 check(0);
 222         }
 223
 224         printk(KERN_ALERT "augmented rbtree testing");
 225
 226         init();
 227
 228         time1 = get_cycles();
 229
 230         for (i = 0; i < perf_loops; i++) {
 231                 for (j = 0; j < nnodes; j++)
 232                         insert_augmented(nodes + j, &root);
 233                 for (j = 0; j < nnodes; j++)
 234                         erase_augmented(nodes + j, &root);
 235         }
 236
 237         time2 = get_cycles();
 238         time = time2 - time1;
 239
 240         time = div_u64(time, perf_loops);
 241         printk(" -> %llu cycles\n", (unsigned long long)time);
 242
 243         for (i = 0; i < check_loops; i++) {
 244                 init();
 245                 for (j = 0; j < nnodes; j++) {
 246                         check_augmented(j);
 247                         insert_augmented(nodes + j, &root);
 248                 }
 249                 for (j = 0; j < nnodes; j++) {
 250                         check_augmented(nnodes - j);
 251                         erase_augmented(nodes + j, &root);
 252                 }
 253                 check_augmented(0);
 254         }
 255
 256         kfree(nodes);
 257
 258         return -EAGAIN; /* Fail will directly unload the module */
 259 }
 260
 261 static void __exit rbtree_test_exit(void)
 262 {
 263         printk(KERN_ALERT "test exit\n");
 264 }
 265
 266 module_init(rbtree_test_init)
 267 module_exit(rbtree_test_exit)
 268
 269 MODULE_LICENSE("GPL");
 270 MODULE_AUTHOR("Michel Lespinasse");
 271 MODULE_DESCRIPTION("Red Black Tree test");