X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=rcuja%2Frcuja.c;h=ff018e682cf4b6265bcfb35e8b1898bcc276acd2;hb=f07b240f5d4b2c086abedcdd4f6516753fd934e4;hp=a2815f2b8248e7e6e9689b8eb1dd9147c883c85b;hpb=b4540e8adb5a4d726e9dbcf2388b6e9b628ce990;p=userspace-rcu.git diff --git a/rcuja/rcuja.c b/rcuja/rcuja.c index a2815f2..ff018e6 100644 --- a/rcuja/rcuja.c +++ b/rcuja/rcuja.c @@ -29,6 +29,7 @@ #include #include #include +#include #include #include "rcuja-internal.h" @@ -65,19 +66,27 @@ struct cds_ja_type { * child type. */ #define JA_TYPE_BITS 3 -#define JA_TYPE_MAX_NR (1U << JA_TYPE_BITS) +#define JA_TYPE_MAX_NR (1UL << JA_TYPE_BITS) #define JA_TYPE_MASK (JA_TYPE_MAX_NR - 1) #define JA_PTR_MASK (~JA_TYPE_MASK) #define JA_ENTRY_PER_NODE 256UL #define JA_BITS_PER_BYTE 3 +#define JA_MAX_DEPTH 5 /* Maximum depth, including leafs */ + /* * Entry for NULL node is at index 8 of the table. It is never encoded * in flags. */ #define NODE_INDEX_NULL 8 +/* + * Number of removals needed on a fallback node before we try to shrink + * it. + */ +#define JA_FALLBACK_REMOVAL_COUNT 8 + /* * Iteration on the array to find the right node size for the number of * children stops when it reaches .max_child == 256 (this is the largest @@ -252,28 +261,28 @@ struct cds_ja_inode { static struct cds_ja_inode_flag *ja_node_flag(struct cds_ja_inode *node, - unsigned int type) + unsigned long type) { - assert(type < RCU_JA_NR_TYPES); + assert(type < (1UL << JA_TYPE_BITS)); return (struct cds_ja_inode_flag *) (((unsigned long) node) | type); } static struct cds_ja_inode *ja_node_ptr(struct cds_ja_inode_flag *node) { - return (struct cds_ja_inode *) (((unsigned long) node) | JA_PTR_MASK); + return (struct cds_ja_inode *) (((unsigned long) node) & JA_PTR_MASK); } static -unsigned int ja_node_type(struct cds_ja_inode_flag *node) +unsigned long ja_node_type(struct cds_ja_inode_flag *node) { - unsigned int type; + unsigned long type; if (ja_node_ptr(node) == NULL) { return NODE_INDEX_NULL; } type = (unsigned int) ((unsigned long) node & JA_TYPE_MASK); - assert(type < RCU_JA_NR_TYPES); + assert(type < (1UL << JA_TYPE_BITS)); return type; } @@ -314,6 +323,7 @@ uint8_t ja_linear_node_get_nr_child(const struct cds_ja_type *type, static struct cds_ja_inode_flag *ja_linear_node_get_nth(const struct cds_ja_type *type, struct cds_ja_inode *node, + struct cds_ja_inode_flag ***child_node_flag_ptr, uint8_t n) { uint8_t nr_child; @@ -337,13 +347,15 @@ struct cds_ja_inode_flag *ja_linear_node_get_nth(const struct cds_ja_type *type, if (i >= nr_child) return NULL; pointers = (struct cds_ja_inode_flag **) align_ptr_size(&values[type->max_linear_child]); + if (caa_unlikely(child_node_flag_ptr)) + *child_node_flag_ptr = &pointers[i]; ptr = rcu_dereference(pointers[i]); assert(ja_node_ptr(ptr) != NULL); return ptr; } static -struct cds_ja_inode_flag *ja_linear_node_get_ith_pos(const struct cds_ja_type *type, +void ja_linear_node_get_ith_pos(const struct cds_ja_type *type, struct cds_ja_inode *node, uint8_t i, uint8_t *v, @@ -364,6 +376,7 @@ struct cds_ja_inode_flag *ja_linear_node_get_ith_pos(const struct cds_ja_type *t static struct cds_ja_inode_flag *ja_pool_node_get_nth(const struct cds_ja_type *type, struct cds_ja_inode *node, + struct cds_ja_inode_flag ***child_node_flag_ptr, uint8_t n) { struct cds_ja_inode *linear; @@ -375,7 +388,7 @@ struct cds_ja_inode_flag *ja_pool_node_get_nth(const struct cds_ja_type *type, */ linear = (struct cds_ja_inode *) &node->u.data[((unsigned long) n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order]; - return ja_linear_node_get_nth(type, linear, n); + return ja_linear_node_get_nth(type, linear, child_node_flag_ptr, n); } static @@ -391,10 +404,16 @@ struct cds_ja_inode *ja_pool_node_get_ith_pool(const struct cds_ja_type *type, static struct cds_ja_inode_flag *ja_pigeon_node_get_nth(const struct cds_ja_type *type, struct cds_ja_inode *node, + struct cds_ja_inode_flag ***child_node_flag_ptr, uint8_t n) { + struct cds_ja_inode_flag **child_node_flag; + assert(type->type_class == RCU_JA_PIGEON); - return rcu_dereference(((struct cds_ja_inode_flag **) node->u.data)[n]); + child_node_flag = &((struct cds_ja_inode_flag **) node->u.data)[n]; + if (caa_unlikely(child_node_flag_ptr)) + *child_node_flag_ptr = child_node_flag; + return rcu_dereference(*child_node_flag); } /* @@ -402,7 +421,8 @@ struct cds_ja_inode_flag *ja_pigeon_node_get_nth(const struct cds_ja_type *type, * node_flag is already rcu_dereference'd. */ static -struct cds_ja_inode_flag *ja_node_get_nth(struct cds_ja_inode_flag *node_flag, +struct cds_ja_inode_flag * ja_node_get_nth(struct cds_ja_inode_flag *node_flag, + struct cds_ja_inode_flag ***child_node_flag_ptr, uint8_t n) { unsigned int type_index; @@ -416,11 +436,14 @@ struct cds_ja_inode_flag *ja_node_get_nth(struct cds_ja_inode_flag *node_flag, switch (type->type_class) { case RCU_JA_LINEAR: - return ja_linear_node_get_nth(type, node, n); + return ja_linear_node_get_nth(type, node, + child_node_flag_ptr, n); case RCU_JA_POOL: - return ja_pool_node_get_nth(type, node, n); + return ja_pool_node_get_nth(type, node, + child_node_flag_ptr, n); case RCU_JA_PIGEON: - return ja_pigeon_node_get_nth(type, node, n); + return ja_pigeon_node_get_nth(type, node, + child_node_flag_ptr, n); default: assert(0); return (void *) -1UL; @@ -454,9 +477,9 @@ int ja_linear_node_set_nth(const struct cds_ja_type *type, assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL); nr_child_ptr = &node->u.data[0]; + dbg_printf("linear set nth: nr_child_ptr %p\n", nr_child_ptr); nr_child = *nr_child_ptr; assert(nr_child <= type->max_linear_child); - assert(type->type_class != RCU_JA_LINEAR || nr_child >= type->min_child); values = &node->u.data[1]; for (i = 0; i < nr_child; i++) { @@ -474,6 +497,11 @@ int ja_linear_node_set_nth(const struct cds_ja_type *type, cmm_smp_wmb(); /* write value and pointer before nr_child */ CMM_STORE_SHARED(*nr_child_ptr, nr_child + 1); shadow_node->nr_child++; + dbg_printf("linear set nth: %u child, shadow: %u child, for node %p shadow %p\n", + (unsigned int) CMM_LOAD_SHARED(*nr_child_ptr), + (unsigned int) shadow_node->nr_child, + node, shadow_node); + return 0; } @@ -504,7 +532,7 @@ int ja_pigeon_node_set_nth(const struct cds_ja_type *type, assert(type->type_class == RCU_JA_PIGEON); ptr = &((struct cds_ja_inode_flag **) node->u.data)[n]; - if (*ptr != NULL) + if (*ptr) return -EEXIST; rcu_assign_pointer(*ptr, child_node_flag); shadow_node->nr_child++; @@ -546,47 +574,49 @@ int _ja_node_set_nth(const struct cds_ja_type *type, /* * ja_node_recompact_add: recompact a node, adding a new child. * TODO: for pool type, take selection bit(s) into account. + * Return 0 on success, -ENOENT if need to retry, or other negative + * error value otherwise. */ static int ja_node_recompact_add(struct cds_ja *ja, unsigned int old_type_index, const struct cds_ja_type *old_type, struct cds_ja_inode *old_node, - struct cds_ja_shadow_node **shadow_node, + struct cds_ja_shadow_node *shadow_node, struct cds_ja_inode_flag **old_node_flag, uint8_t n, struct cds_ja_inode_flag *child_node_flag) { unsigned int new_type_index; struct cds_ja_inode *new_node; + struct cds_ja_shadow_node *new_shadow_node; const struct cds_ja_type *new_type; struct cds_ja_inode_flag *new_node_flag; int ret; + int fallback = 0; - if (*shadow_node == NULL) { + if (!shadow_node || old_type_index == NODE_INDEX_NULL) { new_type_index = 0; } else { new_type_index = old_type_index + 1; } + +retry: /* for fallback */ + dbg_printf("Recompact to type %d\n", new_type_index); new_type = &ja_types[new_type_index]; new_node = alloc_cds_ja_node(new_type); if (!new_node) return -ENOMEM; new_node_flag = ja_node_flag(new_node, new_type_index); - ret = rcuja_shadow_set(ja->ht, new_node, *shadow_node); - if (ret) - return ret; - - if (*shadow_node == NULL) { - *shadow_node = rcuja_shadow_lookup_lock(ja->ht, new_node); - assert(*shadow_node); + dbg_printf("Recompact inherit lock from %p\n", shadow_node); + new_shadow_node = rcuja_shadow_set(ja->ht, new_node, shadow_node); + if (!new_shadow_node) { + free(new_node); + return -ENOMEM; } - - /* - * We need to clear nr_child, because it will be re-incremented - * by _ja_node_set_nth(). - */ - (*shadow_node)->nr_child = 0; + if (fallback) + new_shadow_node->fallback_removal_count = + JA_FALLBACK_REMOVAL_COUNT; assert(old_type->type_class != RCU_JA_PIGEON); switch (old_type->type_class) { @@ -603,8 +633,12 @@ int ja_node_recompact_add(struct cds_ja *ja, ja_linear_node_get_ith_pos(old_type, old_node, i, &v, &iter); if (!iter) continue; - ret = _ja_node_set_nth(new_type, new_node, *shadow_node, + ret = _ja_node_set_nth(new_type, new_node, + new_shadow_node, v, iter); + if (new_type->type_class == RCU_JA_POOL && ret) { + goto fallback_toosmall; + } assert(!ret); } break; @@ -629,71 +663,330 @@ int ja_node_recompact_add(struct cds_ja *ja, j, &v, &iter); if (!iter) continue; - ret = _ja_node_set_nth(new_type, new_node, *shadow_node, + ret = _ja_node_set_nth(new_type, new_node, + new_shadow_node, v, iter); + if (new_type->type_class == RCU_JA_POOL + && ret) { + goto fallback_toosmall; + } assert(!ret); } } break; } + case RCU_JA_NULL: + /* Nothing to copy */ + break; case RCU_JA_PIGEON: default: assert(0); - return -EINVAL; + ret = -EINVAL; + goto end; } /* add node */ - ret = _ja_node_set_nth(new_type, new_node, *shadow_node, + ret = _ja_node_set_nth(new_type, new_node, + new_shadow_node, n, child_node_flag); assert(!ret); - /* Replace the old node with the new recompacted one */ - rcu_assign_pointer(*old_node_flag, new_node_flag); - ret = rcuja_shadow_clear(ja->ht, old_node, + /* Return pointer to new recompacted new through old_node_flag */ + *old_node_flag = new_node_flag; + if (old_node) { + ret = rcuja_shadow_clear(ja->ht, old_node, shadow_node, + RCUJA_SHADOW_CLEAR_FREE_NODE); + assert(!ret); + } + + ret = 0; +end: + return ret; + +fallback_toosmall: + /* fallback if next pool is too small */ + ret = rcuja_shadow_clear(ja->ht, new_node, new_shadow_node, RCUJA_SHADOW_CLEAR_FREE_NODE); assert(!ret); - return 0; + + /* Last type: pigeon */ + new_type_index = (1UL << JA_TYPE_BITS) - 1; + dbg_printf("Fallback to type %d\n", new_type_index); + uatomic_inc(&ja->nr_fallback); + fallback = 1; + goto retry; } +/* + * Return 0 on success, -ENOENT if need to retry, or other negative + * error value otherwise. + */ static int ja_node_set_nth(struct cds_ja *ja, struct cds_ja_inode_flag **node_flag, uint8_t n, - struct cds_ja_inode_flag *child_node_flag) + struct cds_ja_inode_flag *child_node_flag, + struct cds_ja_shadow_node *shadow_node) { int ret; unsigned int type_index; const struct cds_ja_type *type; struct cds_ja_inode *node; - struct cds_ja_shadow_node *shadow_node = NULL; + + dbg_printf("ja_node_set_nth for n=%u, node %p, shadow %p\n", + (unsigned int) n, ja_node_ptr(*node_flag), shadow_node); node = ja_node_ptr(*node_flag); type_index = ja_node_type(*node_flag); type = &ja_types[type_index]; - if (node != NULL) { - shadow_node = rcuja_shadow_lookup_lock(ja->ht, node); - assert(shadow_node); - } ret = _ja_node_set_nth(type, node, shadow_node, n, child_node_flag); if (ret == -ENOSPC) { /* Not enough space in node, need to recompact. */ ret = ja_node_recompact_add(ja, type_index, type, node, - &shadow_node, node_flag, n, child_node_flag); - /* recompact always leave shadow_node locked */ + shadow_node, node_flag, n, child_node_flag); } - rcuja_shadow_unlock(shadow_node); return ret; } -struct cds_ja_node *cds_ja_lookup(uint64_t key) +struct cds_hlist_head *cds_ja_lookup(struct cds_ja *ja, uint64_t key) { - /* TODO */ + unsigned int tree_depth, i; + struct cds_ja_inode_flag *node_flag; + + if (caa_unlikely(key > ja->key_max)) + return NULL; + tree_depth = ja->tree_depth; + node_flag = rcu_dereference(ja->root); + + /* level 0: root node */ + if (!ja_node_ptr(node_flag)) + return NULL; + + for (i = 1; i < tree_depth; i++) { + node_flag = ja_node_get_nth(node_flag, NULL, + (unsigned char) key); + if (!ja_node_ptr(node_flag)) + return NULL; + key >>= JA_BITS_PER_BYTE; + } + + /* Last level lookup succeded. We got an actual match. */ + return (struct cds_hlist_head *) node_flag; +} + +/* + * We reached an unpopulated node. Create it and the children we need, + * and then attach the entire branch to the current node. This may + * trigger recompaction of the current node. Locks needed: node lock + * (for add), and, possibly, parent node lock (to update pointer due to + * node recompaction). + * + * First take node lock, check if recompaction is needed, then take + * parent lock (if needed). Then we can proceed to create the new + * branch. Publish the new branch, and release locks. + * TODO: we currently always take the parent lock even when not needed. + */ +static +int ja_attach_node(struct cds_ja *ja, + struct cds_ja_inode_flag **node_flag_ptr, + struct cds_ja_inode_flag *node_flag, + struct cds_ja_inode_flag *parent_node_flag, + uint64_t key, + unsigned int depth, + struct cds_ja_node *child_node) +{ + struct cds_ja_shadow_node *shadow_node = NULL, + *parent_shadow_node = NULL, + *iter_shadow_node; + struct cds_ja_inode *node = ja_node_ptr(node_flag); + struct cds_ja_inode *parent_node = ja_node_ptr(parent_node_flag); + struct cds_hlist_head head; + struct cds_ja_inode_flag *iter_node_flag, *iter_dest_node_flag; + int ret, i; + struct cds_ja_inode_flag *created_nodes[JA_MAX_DEPTH]; + int nr_created_nodes = 0; + + dbg_printf("Attach node at depth %u\n", depth); + + assert(node); + shadow_node = rcuja_shadow_lookup_lock(ja->ht, node); + if (!shadow_node) { + ret = -ENOENT; + goto end; + } + if (parent_node) { + parent_shadow_node = rcuja_shadow_lookup_lock(ja->ht, + parent_node); + if (!parent_shadow_node) { + ret = -ENOENT; + goto unlock_shadow; + } + } + + /* Create new branch, starting from bottom */ + CDS_INIT_HLIST_HEAD(&head); + cds_hlist_add_head_rcu(&child_node->list, &head); + iter_node_flag = (struct cds_ja_inode_flag *) head.next; + + /* Create shadow node for the leaf node */ + dbg_printf("leaf shadow node creation\n"); + iter_shadow_node = rcuja_shadow_set(ja->ht, + ja_node_ptr(iter_node_flag), NULL); + if (!iter_shadow_node) { + ret = -ENOMEM; + goto check_error; + } + created_nodes[nr_created_nodes++] = iter_node_flag; + + for (i = ja->tree_depth - 1; i >= (int) depth; i--) { + dbg_printf("branch creation level %d, key %" PRIu64 "\n", + i, key >> (JA_BITS_PER_BYTE * (i - 2))); + iter_dest_node_flag = NULL; + ret = ja_node_set_nth(ja, &iter_dest_node_flag, + key >> (JA_BITS_PER_BYTE * (i - 2)), + iter_node_flag, + NULL); + if (ret) + goto check_error; + created_nodes[nr_created_nodes++] = iter_dest_node_flag; + iter_node_flag = iter_dest_node_flag; + } + + if (depth > 1) { + /* We need to use set_nth on the previous level. */ + iter_dest_node_flag = node_flag; + ret = ja_node_set_nth(ja, &iter_dest_node_flag, + key >> (JA_BITS_PER_BYTE * (depth - 2)), + iter_node_flag, + shadow_node); + if (ret) + goto check_error; + created_nodes[nr_created_nodes++] = iter_dest_node_flag; + iter_node_flag = iter_dest_node_flag; + } + + /* Publish new branch */ + dbg_printf("Publish branch %p, replacing %p\n", + iter_node_flag, *node_flag_ptr); + rcu_assign_pointer(*node_flag_ptr, iter_node_flag); + + /* Success */ + ret = 0; + +check_error: + if (ret) { + for (i = 0; i < nr_created_nodes; i++) { + int tmpret; + int flags; + + flags = RCUJA_SHADOW_CLEAR_FREE_LOCK; + if (i) + flags |= RCUJA_SHADOW_CLEAR_FREE_NODE; + tmpret = rcuja_shadow_clear(ja->ht, + ja_node_ptr(created_nodes[i]), + NULL, + flags); + assert(!tmpret); + } + } + if (parent_shadow_node) + rcuja_shadow_unlock(parent_shadow_node); +unlock_shadow: + if (shadow_node) + rcuja_shadow_unlock(shadow_node); +end: + return ret; +} + +/* + * Lock the hlist head shadow node mutex, and add node to list of + * duplicates. Failure can happen if concurrent removal removes the last + * node with same key before we get the lock. + * Return 0 on success, negative error value on failure. + */ +static +int ja_chain_node(struct cds_ja *ja, + struct cds_hlist_head *head, + struct cds_ja_node *node) +{ + struct cds_ja_shadow_node *shadow_node; + + shadow_node = rcuja_shadow_lookup_lock(ja->ht, + (struct cds_ja_inode *) head); + if (!shadow_node) + return -ENOENT; + cds_hlist_add_head_rcu(&node->list, head); + rcuja_shadow_unlock(shadow_node); + return 0; +} + +int cds_ja_add(struct cds_ja *ja, uint64_t key, + struct cds_ja_node *new_node) +{ + unsigned int tree_depth, i; + uint64_t iter_key; + struct cds_ja_inode_flag **node_flag_ptr; /* in parent */ + struct cds_ja_inode_flag *node_flag, + *parent_node_flag, + *parent2_node_flag; + int ret; + + if (caa_unlikely(key > ja->key_max)) + return -EINVAL; + tree_depth = ja->tree_depth; + +retry: + dbg_printf("cds_ja_add attempt: key %" PRIu64 ", node %p\n", + key, new_node); + iter_key = key; + parent2_node_flag = NULL; + parent_node_flag = + (struct cds_ja_inode_flag *) &ja->root; /* Use root ptr address as key for mutex */ + node_flag_ptr = &ja->root; + node_flag = rcu_dereference(*node_flag_ptr); + + /* Iterate on all internal levels */ + for (i = 1; i < tree_depth; i++) { + if (!ja_node_ptr(node_flag)) { + ret = ja_attach_node(ja, node_flag_ptr, + parent_node_flag, parent2_node_flag, + key, i, new_node); + if (ret == -ENOENT || ret == -EEXIST) + goto retry; + else + goto end; + } + parent2_node_flag = parent_node_flag; + parent_node_flag = node_flag; + node_flag = ja_node_get_nth(node_flag, + &node_flag_ptr, + (unsigned char) iter_key); + iter_key >>= JA_BITS_PER_BYTE; + } + + /* + * We reached bottom of tree, simply add node to last internal + * level, or chain it if key is already present. + */ + if (!ja_node_ptr(node_flag)) { + ret = ja_attach_node(ja, node_flag_ptr, parent_node_flag, + parent2_node_flag, key, i, new_node); + } else { + ret = ja_chain_node(ja, + (struct cds_hlist_head *) ja_node_ptr(node_flag), + new_node); + } + if (ret == -ENOENT) + goto retry; +end: + return ret; } struct cds_ja *_cds_ja_new(unsigned int key_bits, const struct rcu_flavor_struct *flavor) { struct cds_ja *ja; - + int ret; + struct cds_ja_shadow_node *root_shadow_node; ja = calloc(sizeof(*ja), 1); if (!ja) @@ -717,12 +1010,29 @@ struct cds_ja *_cds_ja_new(unsigned int key_bits, } /* ja->root is NULL */ - ja->tree_depth = key_bits >> JA_BITS_PER_BYTE; + /* tree_depth 0 is for pointer to root node */ + ja->tree_depth = (key_bits >> JA_BITS_PER_BYTE) + 1; + assert(ja->tree_depth <= JA_MAX_DEPTH); ja->ht = rcuja_create_ht(flavor); if (!ja->ht) goto ht_error; + + /* + * Note: we should not free this node until judy array destroy. + */ + root_shadow_node = rcuja_shadow_set(ja->ht, + ja_node_ptr((struct cds_ja_inode_flag *) &ja->root), + NULL); + if (!root_shadow_node) { + ret = -ENOMEM; + goto ht_node_error; + } + return ja; +ht_node_error: + ret = rcuja_delete_ht(ja->ht); + assert(!ret); ht_error: check_error: free(ja); @@ -743,5 +1053,10 @@ int cds_ja_destroy(struct cds_ja *ja) ret = rcuja_delete_ht(ja->ht); if (ret) return ret; + if (uatomic_read(&ja->nr_fallback)) + fprintf(stderr, + "[warning] RCU Judy Array used %lu fallback node(s)\n", + uatomic_read(&ja->nr_fallback)); free(ja); + return 0; }