// SPDX-License-Identifier: GPL-2.0-only #include <linux/module.h> #include <linux/moduleparam.h> #include <linux/rbtree_augmented.h> #include <linux/random.h> #include <linux/slab.h> #include <asm/timex.h> #define __param(type, name, init, msg) \ static type name = init; \ module_param(name, type, 0444); \ MODULE_PARM_DESC(name, msg); __param(int, nnodes, 100, "Number of nodes in the rb-tree"); __param(int, perf_loops, 1000, "Number of iterations modifying the rb-tree"); __param(int, check_loops, 100, "Number of iterations modifying and verifying the rb-tree"); struct test_node { u32 key; struct rb_node rb; /* following fields used for testing augmented rbtree functionality */ u32 val; u32 augmented; }; static struct rb_root_cached root = RB_ROOT_CACHED; static struct test_node *nodes = NULL; static struct rnd_state rnd; static void insert(struct test_node *node, struct rb_root_cached *root) { struct rb_node **new = &root->rb_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->rb_root); } static void insert_cached(struct test_node *node, struct rb_root_cached *root) { struct rb_node **new = &root->rb_root.rb_node, *parent = NULL; u32 key = node->key; bool leftmost = true; while (*new) { parent = *new; if (key < rb_entry(parent, struct test_node, rb)->key) new = &parent->rb_left; else { new = &parent->rb_right; leftmost = false; } } rb_link_node(&node->rb, parent, new); rb_insert_color_cached(&node->rb, root, leftmost); } static inline void erase(struct test_node *node, struct rb_root_cached *root) { rb_erase(&node->rb, &root->rb_root); } static inline void erase_cached(struct test_node *node, struct rb_root_cached *root) { rb_erase_cached(&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_cached *root) { struct rb_node **new = &root->rb_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->rb_root, &augment_callbacks); } static void insert_augmented_cached(struct test_node *node, struct rb_root_cached *root) { struct rb_node **new = &root->rb_root.rb_node, *rb_parent = NULL; u32 key = node->key; u32 val = node->val; struct test_node *parent; bool leftmost = true; 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; leftmost = false; } } node->augmented = val; rb_link_node(&node->rb, rb_parent, new); rb_insert_augmented_cached(&node->rb, root, leftmost, &augment_callbacks); } static void erase_augmented(struct test_node *node, struct rb_root_cached *root) { rb_erase_augmented(&node->rb, &root->rb_root, &augment_callbacks); } static void erase_augmented_cached(struct test_node *node, struct rb_root_cached *root) { rb_erase_augmented_cached(&node->rb, root, &augment_callbacks); } static void init(void) { int i; for (i = 0; i < nnodes; i++) { nodes[i].key = prandom_u32_state(&rnd); nodes[i].val = prandom_u32_state(&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_postorder_foreach(int nr_nodes) { struct test_node *cur, *n; int count = 0; rbtree_postorder_for_each_entry_safe(cur, n, &root.rb_root, rb) count++; WARN_ON_ONCE(count != nr_nodes); } static void check_postorder(int nr_nodes) { struct rb_node *rb; int count = 0; for (rb = rb_first_postorder(&root.rb_root); rb; rb = rb_next_postorder(rb)) count++; WARN_ON_ONCE(count != nr_nodes); } static void check(int nr_nodes) { struct rb_node *rb; int count = 0, blacks = 0; u32 prev_key = 0; for (rb = rb_first(&root.rb_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); WARN_ON_ONCE(count < (1 << black_path_count(rb_last(&root.rb_root))) - 1); check_postorder(nr_nodes); check_postorder_foreach(nr_nodes); } static void check_augmented(int nr_nodes) { struct rb_node *rb; check(nr_nodes); for (rb = rb_first(&root.rb_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 __init rbtree_test_init(void) { int i, j; cycles_t time1, time2, time; struct rb_node *node; nodes = kmalloc_array(nnodes, sizeof(*nodes), GFP_KERNEL); if (!nodes) return -ENOMEM; printk(KERN_ALERT "rbtree testing"); prandom_seed_state(&rnd, 3141592653589793238ULL); init(); time1 = get_cycles(); for (i = 0; i < perf_loops; i++) { for (j = 0; j < nnodes; j++) insert(nodes + j, &root); for (j = 0; j < nnodes; j++) erase(nodes + j, &root); } time2 = get_cycles(); time = time2 - time1; time = div_u64(time, perf_loops); printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n", (unsigned long long)time); time1 = get_cycles(); for (i = 0; i < perf_loops; i++) { for (j = 0; j < nnodes; j++) insert_cached(nodes + j, &root); for (j = 0; j < nnodes; j++) erase_cached(nodes + j, &root); } time2 = get_cycles(); time = time2 - time1; time = div_u64(time, perf_loops); printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n", (unsigned long long)time); for (i = 0; i < nnodes; i++) insert(nodes + i, &root); time1 = get_cycles(); for (i = 0; i < perf_loops; i++) { for (node = rb_first(&root.rb_root); node; node = rb_next(node)) ; } time2 = get_cycles(); time = time2 - time1; time = div_u64(time, perf_loops); printk(" -> test 3 (latency of inorder traversal): %llu cycles\n", (unsigned long long)time); time1 = get_cycles(); for (i = 0; i < perf_loops; i++) node = rb_first(&root.rb_root); time2 = get_cycles(); time = time2 - time1; time = div_u64(time, perf_loops); printk(" -> test 4 (latency to fetch first node)\n"); printk(" non-cached: %llu cycles\n", (unsigned long long)time); time1 = get_cycles(); for (i = 0; i < perf_loops; i++) node = rb_first_cached(&root); time2 = get_cycles(); time = time2 - time1; time = div_u64(time, perf_loops); printk(" cached: %llu cycles\n", (unsigned long long)time); for (i = 0; i < nnodes; i++) erase(nodes + i, &root); /* run checks */ for (i = 0; i < check_loops; i++) { init(); for (j = 0; j < nnodes; j++) { check(j); insert(nodes + j, &root); } for (j = 0; j < nnodes; j++) { check(nnodes - 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 < nnodes; j++) insert_augmented(nodes + j, &root); for (j = 0; j < nnodes; j++) erase_augmented(nodes + j, &root); } time2 = get_cycles(); time = time2 - time1; time = div_u64(time, perf_loops); printk(" -> test 1 (latency of nnodes insert+delete): %llu cycles\n", (unsigned long long)time); time1 = get_cycles(); for (i = 0; i < perf_loops; i++) { for (j = 0; j < nnodes; j++) insert_augmented_cached(nodes + j, &root); for (j = 0; j < nnodes; j++) erase_augmented_cached(nodes + j, &root); } time2 = get_cycles(); time = time2 - time1; time = div_u64(time, perf_loops); printk(" -> test 2 (latency of nnodes cached insert+delete): %llu cycles\n", (unsigned long long)time); for (i = 0; i < check_loops; i++) { init(); for (j = 0; j < nnodes; j++) { check_augmented(j); insert_augmented(nodes + j, &root); } for (j = 0; j < nnodes; j++) { check_augmented(nnodes - j); erase_augmented(nodes + j, &root); } check_augmented(0); } kfree(nodes); return -EAGAIN; /* Fail will directly unload the module */ } static void __exit 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");