1 files changed, 234 insertions, 0 deletions

diff --git a/lib/rbtree_test.c b/lib/rbtree_test.c
new file mode 100644
index 000000000000..268b23951fec
--- /dev/null
+++ b/lib/rbtree_test.c
@@ -0,0 +1,234 @@
+#include <linux/module.h>
+#include <linux/rbtree_augmented.h>
+#include <linux/random.h>
+#include <asm/timex.h>
+
+#define NODES       100
+#define PERF_LOOPS  100000
+#define CHECK_LOOPS 100
+
+struct test_node {
+        struct rb_node rb;
+        u32 key;
+
+        /* following fields used for testing augmented rbtree functionality */
+        u32 val;
+        u32 augmented;
+};
+
+static struct rb_root root = RB_ROOT;
+static struct test_node nodes[NODES];
+
+static struct rnd_state rnd;
+
+static void insert(struct test_node *node, struct rb_root *root)
+{
+        struct rb_node **new = &root->rb_node, *parent = NULL;
+        u32 key = node->key;
+
+        while (*new) {
+                parent = *new;
+                if (key < rb_entry(parent, struct test_node, rb)->key)
+                        new = &parent->rb_left;
+                else
+                        new = &parent->rb_right;
+        }
+
+        rb_link_node(&node->rb, parent, new);
+        rb_insert_color(&node->rb, root);
+}
+
+static inline void erase(struct test_node *node, struct rb_root *root)
+{
+        rb_erase(&node->rb, root);
+}
+
+static inline u32 augment_recompute(struct test_node *node)
+{
+        u32 max = node->val, child_augmented;
+        if (node->rb.rb_left) {
+                child_augmented = rb_entry(node->rb.rb_left, struct test_node,
+                                           rb)->augmented;
+                if (max < child_augmented)
+                        max = child_augmented;
+        }
+        if (node->rb.rb_right) {
+                child_augmented = rb_entry(node->rb.rb_right, struct test_node,
+                                           rb)->augmented;
+                if (max < child_augmented)
+                        max = child_augmented;
+        }
+        return max;
+}
+
+RB_DECLARE_CALLBACKS(static, augment_callbacks, struct test_node, rb,
+                     u32, augmented, augment_recompute)
+
+static void insert_augmented(struct test_node *node, struct rb_root *root)
+{
+        struct rb_node **new = &root->rb_node, *rb_parent = NULL;
+        u32 key = node->key;
+        u32 val = node->val;
+        struct test_node *parent;
+
+        while (*new) {
+                rb_parent = *new;
+                parent = rb_entry(rb_parent, struct test_node, rb);
+                if (parent->augmented < val)
+                        parent->augmented = val;
+                if (key < parent->key)
+                        new = &parent->rb.rb_left;
+                else
+                        new = &parent->rb.rb_right;
+        }
+
+        node->augmented = val;
+        rb_link_node(&node->rb, rb_parent, new);
+        rb_insert_augmented(&node->rb, root, &augment_callbacks);
+}
+
+static void erase_augmented(struct test_node *node, struct rb_root *root)
+{
+        rb_erase_augmented(&node->rb, root, &augment_callbacks);
+}
+
+static void init(void)
+{
+        int i;
+        for (i = 0; i < NODES; i++) {
+                nodes[i].key = prandom32(&rnd);
+                nodes[i].val = prandom32(&rnd);
+        }
+}
+
+static bool is_red(struct rb_node *rb)
+{
+        return !(rb->__rb_parent_color & 1);
+}
+
+static int black_path_count(struct rb_node *rb)
+{
+        int count;
+        for (count = 0; rb; rb = rb_parent(rb))
+                count += !is_red(rb);
+        return count;
+}
+
+static void check(int nr_nodes)
+{
+        struct rb_node *rb;
+        int count = 0;
+        int blacks;
+        u32 prev_key = 0;
+
+        for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
+                struct test_node *node = rb_entry(rb, struct test_node, rb);
+                WARN_ON_ONCE(node->key < prev_key);
+                WARN_ON_ONCE(is_red(rb) &&
+                             (!rb_parent(rb) || is_red(rb_parent(rb))));
+                if (!count)
+                        blacks = black_path_count(rb);
+                else
+                        WARN_ON_ONCE((!rb->rb_left || !rb->rb_right) &&
+                                     blacks != black_path_count(rb));
+                prev_key = node->key;
+                count++;
+        }
+        WARN_ON_ONCE(count != nr_nodes);
+}
+
+static void check_augmented(int nr_nodes)
+{
+        struct rb_node *rb;
+
+        check(nr_nodes);
+        for (rb = rb_first(&root); rb; rb = rb_next(rb)) {
+                struct test_node *node = rb_entry(rb, struct test_node, rb);
+                WARN_ON_ONCE(node->augmented != augment_recompute(node));
+        }
+}
+
+static int rbtree_test_init(void)
+{
+        int i, j;
+        cycles_t time1, time2, time;
+
+        printk(KERN_ALERT "rbtree testing");
+
+        prandom32_seed(&rnd, 3141592653589793238ULL);
+        init();
+
+        time1 = get_cycles();
+
+        for (i = 0; i < PERF_LOOPS; i++) {
+                for (j = 0; j < NODES; j++)
+                        insert(nodes + j, &root);
+                for (j = 0; j < NODES; j++)
+                        erase(nodes + j, &root);
+        }
+
+        time2 = get_cycles();
+        time = time2 - time1;
+
+        time = div_u64(time, PERF_LOOPS);
+        printk(" -> %llu cycles\n", (unsigned long long)time);
+
+        for (i = 0; i < CHECK_LOOPS; i++) {
+                init();
+                for (j = 0; j < NODES; j++) {
+                        check(j);
+                        insert(nodes + j, &root);
+                }
+                for (j = 0; j < NODES; j++) {
+                        check(NODES - j);
+                        erase(nodes + j, &root);
+                }
+                check(0);
+        }
+
+        printk(KERN_ALERT "augmented rbtree testing");
+
+        init();
+
+        time1 = get_cycles();
+
+        for (i = 0; i < PERF_LOOPS; i++) {
+                for (j = 0; j < NODES; j++)
+                        insert_augmented(nodes + j, &root);
+                for (j = 0; j < NODES; j++)
+                        erase_augmented(nodes + j, &root);
+        }
+
+        time2 = get_cycles();
+        time = time2 - time1;
+
+        time = div_u64(time, PERF_LOOPS);
+        printk(" -> %llu cycles\n", (unsigned long long)time);
+
+        for (i = 0; i < CHECK_LOOPS; i++) {
+                init();
+                for (j = 0; j < NODES; j++) {
+                        check_augmented(j);
+                        insert_augmented(nodes + j, &root);
+                }
+                for (j = 0; j < NODES; j++) {
+                        check_augmented(NODES - j);
+                        erase_augmented(nodes + j, &root);
+                }
+                check_augmented(0);
+        }
+
+        return -EAGAIN; /* Fail will directly unload the module */
+}
+
+static void rbtree_test_exit(void)
+{
+        printk(KERN_ALERT "test exit\n");
+}
+
+module_init(rbtree_test_init)
+module_exit(rbtree_test_exit)
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Michel Lespinasse");
+MODULE_DESCRIPTION("Red Black Tree test");