X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=rcuja%2Frcuja.c;h=7402cf31f21119b26145bd7d90d0f11bc4b34637;hb=d810c97fa1a23582360b32a91c2eac45a3bde385;hp=75113954ccdb9dee09193a41321002b623bd6cfd;hpb=582a6ade5032f98b788f1d8ddae97d44acf46715;p=userspace-rcu.git diff --git a/rcuja/rcuja.c b/rcuja/rcuja.c index 7511395..7402cf3 100644 --- a/rcuja/rcuja.c +++ b/rcuja/rcuja.c @@ -61,33 +61,6 @@ struct cds_ja_type { uint16_t pool_size_order; /* pool size */ }; -/* - * Number of least significant pointer bits reserved to represent the - * child type. - */ -#define JA_TYPE_BITS 3 -#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_LOG2_BITS_PER_BYTE 3U -#define JA_BITS_PER_BYTE (1U << JA_LOG2_BITS_PER_BYTE) - -#define JA_MAX_DEPTH 9 /* 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 @@ -260,32 +233,11 @@ struct cds_ja_inode { } u; }; -static -struct cds_ja_inode_flag *ja_node_flag(struct cds_ja_inode *node, - unsigned long type) -{ - 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); -} - -static -unsigned long ja_node_type(struct cds_ja_inode_flag *node) -{ - unsigned long type; - - if (ja_node_ptr(node) == NULL) { - return NODE_INDEX_NULL; - } - type = (unsigned int) ((unsigned long) node & JA_TYPE_MASK); - assert(type < (1UL << JA_TYPE_BITS)); - return type; -} +enum ja_recompact { + JA_RECOMPACT, + JA_RECOMPACT_ADD, + JA_RECOMPACT_DEL, +}; struct cds_ja_inode *alloc_cds_ja_node(const struct cds_ja_type *ja_type) { @@ -313,7 +265,7 @@ uint8_t ja_linear_node_get_nr_child(const struct cds_ja_type *type, struct cds_ja_inode *node) { assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL); - return CMM_LOAD_SHARED(node->u.data[0]); + return rcu_dereference(node->u.data[0]); } /* @@ -325,6 +277,7 @@ 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, + struct cds_ja_inode_flag ***node_flag_ptr, uint8_t n) { uint8_t nr_child; @@ -345,13 +298,17 @@ struct cds_ja_inode_flag *ja_linear_node_get_nth(const struct cds_ja_type *type, if (CMM_LOAD_SHARED(values[i]) == n) break; } - if (i >= nr_child) + if (i >= nr_child) { + if (caa_unlikely(node_flag_ptr)) + *node_flag_ptr = NULL; 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); + if (caa_unlikely(child_node_flag_ptr) && ptr) + *child_node_flag_ptr = &pointers[i]; + if (caa_unlikely(node_flag_ptr)) + *node_flag_ptr = &pointers[i]; return ptr; } @@ -378,6 +335,7 @@ 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, + struct cds_ja_inode_flag ***node_flag_ptr, uint8_t n) { struct cds_ja_inode *linear; @@ -389,7 +347,8 @@ 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, child_node_flag_ptr, n); + return ja_linear_node_get_nth(type, linear, child_node_flag_ptr, + node_flag_ptr, n); } static @@ -406,6 +365,7 @@ 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, + struct cds_ja_inode_flag ***node_flag_ptr, uint8_t n) { struct cds_ja_inode_flag **child_node_flag; @@ -416,9 +376,19 @@ struct cds_ja_inode_flag *ja_pigeon_node_get_nth(const struct cds_ja_type *type, child_node_flag); if (caa_unlikely(child_node_flag_ptr) && *child_node_flag) *child_node_flag_ptr = child_node_flag; + if (caa_unlikely(node_flag_ptr)) + *node_flag_ptr = child_node_flag; return rcu_dereference(*child_node_flag); } +static +struct cds_ja_inode_flag *ja_pigeon_node_get_ith_pos(const struct cds_ja_type *type, + struct cds_ja_inode *node, + uint8_t i) +{ + return ja_pigeon_node_get_nth(type, node, NULL, NULL, i); +} + /* * ja_node_get_nth: get nth item from a node. * node_flag is already rcu_dereference'd. @@ -426,6 +396,7 @@ struct cds_ja_inode_flag *ja_pigeon_node_get_nth(const struct cds_ja_type *type, static 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, + struct cds_ja_inode_flag ***node_flag_ptr, uint8_t n) { unsigned int type_index; @@ -440,31 +411,19 @@ 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, - child_node_flag_ptr, n); + child_node_flag_ptr, node_flag_ptr, n); case RCU_JA_POOL: return ja_pool_node_get_nth(type, node, - child_node_flag_ptr, n); + child_node_flag_ptr, node_flag_ptr, n); case RCU_JA_PIGEON: return ja_pigeon_node_get_nth(type, node, - child_node_flag_ptr, n); + child_node_flag_ptr, node_flag_ptr, n); default: assert(0); return (void *) -1UL; } } -/* - * TODO: use ja_get_nr_child to monitor limits triggering shrink - * recompaction. - * Also use ja_get_nr_child to make the difference between resize and - * pool change of compaction bit(s). - */ -static -unsigned int ja_get_nr_child(struct cds_ja_shadow_node *shadow_node) -{ - return shadow_node->nr_child; -} - static int ja_linear_node_set_nth(const struct cds_ja_type *type, struct cds_ja_inode *node, @@ -475,7 +434,7 @@ int ja_linear_node_set_nth(const struct cds_ja_type *type, uint8_t nr_child; uint8_t *values, *nr_child_ptr; struct cds_ja_inode_flag **pointers; - unsigned int i; + unsigned int i, unused = 0; assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL); @@ -485,20 +444,35 @@ int ja_linear_node_set_nth(const struct cds_ja_type *type, assert(nr_child <= type->max_linear_child); values = &node->u.data[1]; + pointers = (struct cds_ja_inode_flag **) align_ptr_size(&values[type->max_linear_child]); + /* Check if node value is already populated */ for (i = 0; i < nr_child; i++) { - if (values[i] == n) - return -EEXIST; + if (values[i] == n) { + if (pointers[i]) + return -EEXIST; + else + break; + } else { + if (!pointers[i]) + unused++; + } } - if (nr_child >= type->max_linear_child) { - /* No space left in this node type */ - return -ENOSPC; + if (i == nr_child && nr_child >= type->max_linear_child) { + if (unused) + return -ERANGE; /* recompact node */ + else + return -ENOSPC; /* No space left in this node type */ + } + + assert(pointers[i] == NULL); + rcu_assign_pointer(pointers[i], child_node_flag); + /* If we expanded the nr_child, increment it */ + if (i == nr_child) { + CMM_STORE_SHARED(values[nr_child], n); + /* write pointer and value before nr_child */ + cmm_smp_wmb(); + CMM_STORE_SHARED(*nr_child_ptr, nr_child + 1); } - pointers = (struct cds_ja_inode_flag **) align_ptr_size(&values[type->max_linear_child]); - assert(pointers[nr_child] == NULL); - rcu_assign_pointer(pointers[nr_child], child_node_flag); - CMM_STORE_SHARED(values[nr_child], n); - 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), @@ -545,7 +519,6 @@ int ja_pigeon_node_set_nth(const struct cds_ja_type *type, /* * _ja_node_set_nth: set nth item within a node. Return an error * (negative error value) if it is already there. - * TODO: exclusive access on node. */ static int _ja_node_set_nth(const struct cds_ja_type *type, @@ -574,55 +547,181 @@ int _ja_node_set_nth(const struct cds_ja_type *type, return 0; } +static +int ja_linear_node_clear_ptr(const struct cds_ja_type *type, + struct cds_ja_inode *node, + struct cds_ja_shadow_node *shadow_node, + struct cds_ja_inode_flag **node_flag_ptr) +{ + uint8_t nr_child; + uint8_t *nr_child_ptr; + + assert(type->type_class == RCU_JA_LINEAR || type->type_class == RCU_JA_POOL); + + nr_child_ptr = &node->u.data[0]; + dbg_printf("linear clear ptr: nr_child_ptr %p\n", nr_child_ptr); + nr_child = *nr_child_ptr; + assert(nr_child <= type->max_linear_child); + + if (shadow_node->fallback_removal_count) { + shadow_node->fallback_removal_count--; + } else { + if (shadow_node->nr_child <= type->min_child) { + /* We need to try recompacting the node */ + return -EFBIG; + } + } + assert(*node_flag_ptr != NULL); + rcu_assign_pointer(*node_flag_ptr, NULL); + /* + * Value and nr_child are never changed (would cause ABA issue). + * Instead, we leave the pointer to NULL and recompact the node + * once in a while. It is allowed to set a NULL pointer to a new + * value without recompaction though. + * Only update the shadow node accounting. + */ + shadow_node->nr_child--; + dbg_printf("linear clear ptr: %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; +} + +static +int ja_pool_node_clear_ptr(const struct cds_ja_type *type, + struct cds_ja_inode *node, + struct cds_ja_shadow_node *shadow_node, + struct cds_ja_inode_flag **node_flag_ptr, + uint8_t n) +{ + struct cds_ja_inode *linear; + + assert(type->type_class == RCU_JA_POOL); + 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_clear_ptr(type, linear, shadow_node, node_flag_ptr); +} + +static +int ja_pigeon_node_clear_ptr(const struct cds_ja_type *type, + struct cds_ja_inode *node, + struct cds_ja_shadow_node *shadow_node, + struct cds_ja_inode_flag **node_flag_ptr) +{ + assert(type->type_class == RCU_JA_PIGEON); + dbg_printf("ja_pigeon_node_clear_ptr: clearing ptr: %p\n", *node_flag_ptr); + rcu_assign_pointer(*node_flag_ptr, NULL); + shadow_node->nr_child--; + return 0; +} + +/* + * _ja_node_clear_ptr: clear ptr item within a node. Return an error + * (negative error value) if it is not found (-ENOENT). + */ +static +int _ja_node_clear_ptr(const struct cds_ja_type *type, + struct cds_ja_inode *node, + struct cds_ja_shadow_node *shadow_node, + struct cds_ja_inode_flag **node_flag_ptr, + uint8_t n) +{ + switch (type->type_class) { + case RCU_JA_LINEAR: + return ja_linear_node_clear_ptr(type, node, shadow_node, node_flag_ptr); + case RCU_JA_POOL: + return ja_pool_node_clear_ptr(type, node, shadow_node, node_flag_ptr, n); + case RCU_JA_PIGEON: + return ja_pigeon_node_clear_ptr(type, node, shadow_node, node_flag_ptr); + case RCU_JA_NULL: + return -ENOENT; + default: + assert(0); + return -EINVAL; + } + + return 0; +} + /* * 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 + * Return 0 on success, -EAGAIN if need to retry, or other negative * error value otherwise. */ static -int ja_node_recompact_add(struct cds_ja *ja, +int ja_node_recompact(enum ja_recompact mode, + 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_inode_flag **old_node_flag, uint8_t n, - struct cds_ja_inode_flag *child_node_flag) + struct cds_ja_inode_flag **old_node_flag_ptr, uint8_t n, + struct cds_ja_inode_flag *child_node_flag, + struct cds_ja_inode_flag **nullify_node_flag_ptr) { unsigned int new_type_index; struct cds_ja_inode *new_node; - struct cds_ja_shadow_node *new_shadow_node; + struct cds_ja_shadow_node *new_shadow_node = NULL; const struct cds_ja_type *new_type; - struct cds_ja_inode_flag *new_node_flag; + struct cds_ja_inode_flag *new_node_flag, *old_node_flag; int ret; int fallback = 0; - if (!shadow_node || old_type_index == NODE_INDEX_NULL) { - new_type_index = 0; - } else { - new_type_index = old_type_index + 1; + old_node_flag = *old_node_flag_ptr; + + switch (mode) { + case JA_RECOMPACT: + new_type_index = old_type_index; + break; + case JA_RECOMPACT_ADD: + if (!shadow_node || old_type_index == NODE_INDEX_NULL) { + new_type_index = 0; + } else { + new_type_index = old_type_index + 1; + } + break; + case JA_RECOMPACT_DEL: + if (old_type_index == 0) { + new_type_index = NODE_INDEX_NULL; + } else { + new_type_index = old_type_index - 1; + } + break; + default: + assert(0); } retry: /* for fallback */ dbg_printf("Recompact from type %d to type %d\n", old_type_index, 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); - - 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; + if (new_type_index != NODE_INDEX_NULL) { + new_node = alloc_cds_ja_node(new_type); + if (!new_node) + return -ENOMEM; + new_node_flag = ja_node_flag(new_node, new_type_index); + dbg_printf("Recompact inherit lock from %p\n", shadow_node); + new_shadow_node = rcuja_shadow_set(ja->ht, new_node_flag, shadow_node, ja); + if (!new_shadow_node) { + free(new_node); + return -ENOMEM; + } + if (fallback) + new_shadow_node->fallback_removal_count = + JA_FALLBACK_REMOVAL_COUNT; + } else { + new_node = NULL; + new_node_flag = NULL; } - if (fallback) - new_shadow_node->fallback_removal_count = - JA_FALLBACK_REMOVAL_COUNT; - assert(old_type->type_class != RCU_JA_PIGEON); + assert(mode != JA_RECOMPACT_ADD || old_type->type_class != RCU_JA_PIGEON); + + if (new_type_index == NODE_INDEX_NULL) + goto skip_copy; + switch (old_type->type_class) { case RCU_JA_LINEAR: { @@ -637,6 +736,8 @@ retry: /* for fallback */ ja_linear_node_get_ith_pos(old_type, old_node, i, &v, &iter); if (!iter) continue; + if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter) + continue; ret = _ja_node_set_nth(new_type, new_node, new_shadow_node, v, iter); @@ -667,6 +768,8 @@ retry: /* for fallback */ j, &v, &iter); if (!iter) continue; + if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter) + continue; ret = _ja_node_set_nth(new_type, new_node, new_shadow_node, v, iter); @@ -680,25 +783,62 @@ retry: /* for fallback */ break; } case RCU_JA_NULL: - /* Nothing to copy */ + assert(mode == JA_RECOMPACT_ADD); break; case RCU_JA_PIGEON: + { + uint8_t nr_child; + unsigned int i; + + assert(mode == JA_RECOMPACT_DEL); + nr_child = shadow_node->nr_child; + for (i = 0; i < nr_child; i++) { + struct cds_ja_inode_flag *iter; + + iter = ja_pigeon_node_get_ith_pos(old_type, old_node, i); + if (!iter) + continue; + if (mode == JA_RECOMPACT_DEL && *nullify_node_flag_ptr == iter) + continue; + ret = _ja_node_set_nth(new_type, new_node, + new_shadow_node, + i, iter); + if (new_type->type_class == RCU_JA_POOL && ret) { + goto fallback_toosmall; + } + assert(!ret); + } + break; + } default: assert(0); ret = -EINVAL; goto end; } +skip_copy: - /* add node */ - ret = _ja_node_set_nth(new_type, new_node, - new_shadow_node, - n, child_node_flag); - assert(!ret); - /* Return pointer to new recompacted new through old_node_flag */ - *old_node_flag = new_node_flag; + if (mode == JA_RECOMPACT_ADD) { + /* add node */ + ret = _ja_node_set_nth(new_type, new_node, + new_shadow_node, + n, child_node_flag); + assert(!ret); + } + /* Return pointer to new recompacted node through old_node_flag_ptr */ + *old_node_flag_ptr = new_node_flag; if (old_node) { - ret = rcuja_shadow_clear(ja->ht, old_node, shadow_node, - RCUJA_SHADOW_CLEAR_FREE_NODE); + int flags; + + flags = RCUJA_SHADOW_CLEAR_FREE_NODE; + /* + * It is OK to free the lock associated with a node + * going to NULL, since we are holding the parent lock. + * This synchronizes removal with re-add of that node. + */ + if (new_type_index == NODE_INDEX_NULL) + flags = RCUJA_SHADOW_CLEAR_FREE_LOCK; + ret = rcuja_shadow_clear(ja->ht, old_node_flag, shadow_node, + flags); assert(!ret); } @@ -708,11 +848,12 @@ end: fallback_toosmall: /* fallback if next pool is too small */ - ret = rcuja_shadow_clear(ja->ht, new_node, new_shadow_node, + assert(new_shadow_node); + ret = rcuja_shadow_clear(ja->ht, new_node_flag, new_shadow_node, RCUJA_SHADOW_CLEAR_FREE_NODE); assert(!ret); - /* Last type: pigeon */ + /* Choose fallback 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); @@ -721,7 +862,7 @@ fallback_toosmall: } /* - * Return 0 on success, -ENOENT if need to retry, or other negative + * Return 0 on success, -EAGAIN if need to retry, or other negative * error value otherwise. */ static @@ -743,42 +884,83 @@ int ja_node_set_nth(struct cds_ja *ja, type = &ja_types[type_index]; ret = _ja_node_set_nth(type, node, shadow_node, n, child_node_flag); - if (ret == -ENOSPC) { + switch (ret) { + case -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); + ret = ja_node_recompact(JA_RECOMPACT_ADD, ja, type_index, type, node, + shadow_node, node_flag, n, child_node_flag, NULL); + break; + case -ERANGE: + /* Node needs to be recompacted. */ + ret = ja_node_recompact(JA_RECOMPACT, ja, type_index, type, node, + shadow_node, node_flag, n, child_node_flag, NULL); + break; } return ret; } -struct cds_hlist_head *cds_ja_lookup(struct cds_ja *ja, uint64_t key) +/* + * Return 0 on success, -EAGAIN if need to retry, or other negative + * error value otherwise. + */ +static +int ja_node_clear_ptr(struct cds_ja *ja, + struct cds_ja_inode_flag **node_flag_ptr, /* Pointer to location to nullify */ + struct cds_ja_inode_flag **parent_node_flag_ptr, /* Address of parent ptr in its parent */ + struct cds_ja_shadow_node *shadow_node, /* of parent */ + uint8_t n) +{ + int ret; + unsigned int type_index; + const struct cds_ja_type *type; + struct cds_ja_inode *node; + + dbg_printf("ja_node_clear_ptr for node %p, shadow %p, target ptr %p\n", + ja_node_ptr(*parent_node_flag_ptr), shadow_node, node_flag_ptr); + + node = ja_node_ptr(*parent_node_flag_ptr); + type_index = ja_node_type(*parent_node_flag_ptr); + type = &ja_types[type_index]; + ret = _ja_node_clear_ptr(type, node, shadow_node, node_flag_ptr, n); + if (ret == -EFBIG) { + /* Should to try recompaction. */ + ret = ja_node_recompact(JA_RECOMPACT_DEL, ja, type_index, type, node, + shadow_node, parent_node_flag_ptr, n, NULL, + node_flag_ptr); + } + return ret; +} + +struct cds_hlist_head cds_ja_lookup(struct cds_ja *ja, uint64_t key) { unsigned int tree_depth, i; struct cds_ja_inode_flag *node_flag; + struct cds_hlist_head head = { NULL }; if (caa_unlikely(key > ja->key_max)) - return NULL; + return head; tree_depth = ja->tree_depth; node_flag = rcu_dereference(ja->root); /* level 0: root node */ if (!ja_node_ptr(node_flag)) - return NULL; + return head; for (i = 1; i < tree_depth; i++) { uint8_t iter_key; iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (tree_depth - i - 1))); - node_flag = ja_node_get_nth(node_flag, NULL, + node_flag = ja_node_get_nth(node_flag, NULL, NULL, iter_key); dbg_printf("cds_ja_lookup iter key lookup %u finds node_flag %p\n", (unsigned int) iter_key, node_flag); if (!ja_node_ptr(node_flag)) - return NULL; + return head; } /* Last level lookup succeded. We got an actual match. */ - return (struct cds_hlist_head *) node_flag; + head.next = (struct cds_hlist_node *) node_flag; + return head; } /* @@ -795,6 +977,7 @@ struct cds_hlist_head *cds_ja_lookup(struct cds_ja *ja, uint64_t key) */ static int ja_attach_node(struct cds_ja *ja, + struct cds_ja_inode_flag **attach_node_flag_ptr, struct cds_ja_inode_flag **node_flag_ptr, struct cds_ja_inode_flag *node_flag, struct cds_ja_inode_flag *parent_node_flag, @@ -803,8 +986,7 @@ int ja_attach_node(struct cds_ja *ja, struct cds_ja_node *child_node) { struct cds_ja_shadow_node *shadow_node = NULL, - *parent_shadow_node = NULL, - *iter_shadow_node; + *parent_shadow_node = NULL; 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; @@ -817,35 +999,35 @@ int ja_attach_node(struct cds_ja *ja, level, node, node_flag); assert(node); - shadow_node = rcuja_shadow_lookup_lock(ja->ht, node); + shadow_node = rcuja_shadow_lookup_lock(ja->ht, node_flag); if (!shadow_node) { - ret = -ENOENT; + ret = -EAGAIN; goto end; } if (parent_node) { parent_shadow_node = rcuja_shadow_lookup_lock(ja->ht, - parent_node); + parent_node_flag); if (!parent_shadow_node) { - ret = -ENOENT; + ret = -EAGAIN; goto unlock_shadow; } } + if (node_flag_ptr && ja_node_ptr(*node_flag_ptr) != NULL) { + /* + * Target node is non-NULL: it has been updated between + * RCU lookup and lock acquisition. We need to re-try + * lookup and attach. + */ + ret = -EAGAIN; + goto unlock_parent; + } + /* 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; i > (int) level; i--) { uint8_t iter_key; @@ -881,8 +1063,8 @@ int ja_attach_node(struct cds_ja *ja, /* 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); + iter_node_flag, *attach_node_flag_ptr); + rcu_assign_pointer(*attach_node_flag_ptr, iter_node_flag); /* Success */ ret = 0; @@ -897,12 +1079,13 @@ check_error: if (i) flags |= RCUJA_SHADOW_CLEAR_FREE_NODE; tmpret = rcuja_shadow_clear(ja->ht, - ja_node_ptr(created_nodes[i]), + created_nodes[i], NULL, flags); assert(!tmpret); } } +unlock_parent: if (parent_shadow_node) rcuja_shadow_unlock(parent_shadow_node); unlock_shadow: @@ -913,22 +1096,23 @@ end: } /* - * 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. + * Lock the parent containing the hlist head pointer, and add node to list of + * duplicates. Failure can happen if concurrent update changes the + * parent before we get the lock. We return -EAGAIN in that case. * Return 0 on success, negative error value on failure. */ static int ja_chain_node(struct cds_ja *ja, + struct cds_ja_inode_flag *parent_node_flag, 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; + shadow_node = rcuja_shadow_lookup_lock(ja->ht, parent_node_flag); + if (!shadow_node) { + return -EAGAIN; + } cds_hlist_add_head_rcu(&node->list, head); rcuja_shadow_unlock(shadow_node); return 0; @@ -938,14 +1122,16 @@ int cds_ja_add(struct cds_ja *ja, uint64_t key, struct cds_ja_node *new_node) { unsigned int tree_depth, i; - struct cds_ja_inode_flag **node_flag_ptr; /* in parent */ + struct cds_ja_inode_flag **attach_node_flag_ptr, + **node_flag_ptr; struct cds_ja_inode_flag *node_flag, *parent_node_flag, *parent2_node_flag; int ret; - if (caa_unlikely(key > ja->key_max)) + if (caa_unlikely(key > ja->key_max)) { return -EINVAL; + } tree_depth = ja->tree_depth; retry: @@ -954,20 +1140,22 @@ retry: parent2_node_flag = NULL; parent_node_flag = (struct cds_ja_inode_flag *) &ja->root; /* Use root ptr address as key for mutex */ + attach_node_flag_ptr = &ja->root; node_flag_ptr = &ja->root; - node_flag = rcu_dereference(*node_flag_ptr); + node_flag = rcu_dereference(ja->root); /* Iterate on all internal levels */ for (i = 1; i < tree_depth; i++) { uint8_t iter_key; - dbg_printf("cds_ja_add iter node_flag_ptr %p node_flag %p\n", - *node_flag_ptr, node_flag); + dbg_printf("cds_ja_add iter attach_node_flag_ptr %p node_flag_ptr %p node_flag %p\n", + *attach_node_flag_ptr, *node_flag_ptr, node_flag); if (!ja_node_ptr(node_flag)) { - ret = ja_attach_node(ja, node_flag_ptr, + ret = ja_attach_node(ja, attach_node_flag_ptr, + node_flag_ptr, parent_node_flag, parent2_node_flag, key, i, new_node); - if (ret == -ENOENT || ret == -EEXIST) + if (ret == -EAGAIN || ret == -EEXIST) goto retry; else goto end; @@ -976,10 +1164,13 @@ retry: parent2_node_flag = parent_node_flag; parent_node_flag = node_flag; node_flag = ja_node_get_nth(node_flag, + &attach_node_flag_ptr, &node_flag_ptr, iter_key); - dbg_printf("cds_ja_add iter key lookup %u finds node_flag %p node_flag_ptr %p\n", - (unsigned int) iter_key, node_flag, *node_flag_ptr); + dbg_printf("cds_ja_add iter key lookup %u finds node_flag %p attach_node_flag_ptr %p node_flag_ptr %p\n", + (unsigned int) iter_key, node_flag, + *attach_node_flag_ptr, + *node_flag_ptr); } /* @@ -987,21 +1178,291 @@ retry: * level, or chain it if key is already present. */ if (!ja_node_ptr(node_flag)) { - dbg_printf("cds_ja_add last node_flag_ptr %p node_flag %p\n", - *node_flag_ptr, node_flag); - ret = ja_attach_node(ja, node_flag_ptr, parent_node_flag, + dbg_printf("cds_ja_add last attach_node_flag_ptr %p node_flag_ptr %p node_flag %p\n", + *attach_node_flag_ptr, *node_flag_ptr, node_flag); + ret = ja_attach_node(ja, attach_node_flag_ptr, + 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), + parent_node_flag, + (struct cds_hlist_head *) attach_node_flag_ptr, new_node); } - if (ret == -ENOENT) + if (ret == -EAGAIN || ret == -EEXIST) goto retry; end: return ret; } +/* + * Note: there is no need to lookup the pointer address associated with + * each node's nth item after taking the lock: it's already been done by + * cds_ja_del while holding the rcu read-side lock, and our node rules + * ensure that when a match value -> pointer is found in a node, it is + * _NEVER_ changed for that node without recompaction, and recompaction + * reallocates the node. + * However, when a child is removed from "linear" nodes, its pointer + * is set to NULL. We therefore check, while holding the locks, if this + * pointer is NULL, and return -ENOENT to the caller if it is the case. + */ +static +int ja_detach_node(struct cds_ja *ja, + struct cds_ja_inode_flag **snapshot, + struct cds_ja_inode_flag ***snapshot_ptr, + uint8_t *snapshot_n, + int nr_snapshot, + uint64_t key, + struct cds_ja_node *node) +{ + struct cds_ja_shadow_node *shadow_nodes[JA_MAX_DEPTH]; + struct cds_ja_inode_flag **node_flag_ptr = NULL, + *parent_node_flag = NULL, + **parent_node_flag_ptr = NULL; + struct cds_ja_inode_flag *iter_node_flag; + int ret, i, nr_shadow = 0, nr_clear = 0, nr_branch = 0; + uint8_t n = 0; + + assert(nr_snapshot == ja->tree_depth + 1); + + /* + * From the last internal level node going up, get the node + * lock, check if the node has only one child left. If it is the + * case, we continue iterating upward. When we reach a node + * which has more that one child left, we lock the parent, and + * proceed to the node deletion (removing its children too). + */ + for (i = nr_snapshot - 2; i >= 1; i--) { + struct cds_ja_shadow_node *shadow_node; + + shadow_node = rcuja_shadow_lookup_lock(ja->ht, + snapshot[i]); + if (!shadow_node) { + ret = -EAGAIN; + goto end; + } + assert(shadow_node->nr_child > 0); + shadow_nodes[nr_shadow++] = shadow_node; + if (shadow_node->nr_child == 1 && i > 1) + nr_clear++; + nr_branch++; + if (shadow_node->nr_child > 1 || i == 1) { + /* Lock parent and break */ + shadow_node = rcuja_shadow_lookup_lock(ja->ht, + snapshot[i - 1]); + if (!shadow_node) { + ret = -EAGAIN; + goto end; + } + shadow_nodes[nr_shadow++] = shadow_node; + node_flag_ptr = snapshot_ptr[i + 1]; + n = snapshot_n[i + 1]; + parent_node_flag_ptr = snapshot_ptr[i]; + parent_node_flag = snapshot[i]; + if (i > 1) { + /* + * Lock parent's parent, in case we need + * to recompact parent. + */ + shadow_node = rcuja_shadow_lookup_lock(ja->ht, + snapshot[i - 2]); + if (!shadow_node) { + ret = -EAGAIN; + goto end; + } + shadow_nodes[nr_shadow++] = shadow_node; + } + break; + } + } + + /* + * Check if node has been removed between RCU lookup and lock + * acquisition. + */ + assert(node_flag_ptr); + if (ja_node_ptr(*node_flag_ptr) == NULL) { + ret = -ENOENT; + goto end; + } + + /* + * At this point, we want to delete all nodes that are about to + * be removed from shadow_nodes (except the last one, which is + * either the root or the parent of the upmost node with 1 + * child). OK to as to free lock here, because RCU read lock is + * held, and free only performed in call_rcu. + */ + + for (i = 0; i < nr_clear; i++) { + ret = rcuja_shadow_clear(ja->ht, + shadow_nodes[i]->node_flag, + shadow_nodes[i], + RCUJA_SHADOW_CLEAR_FREE_NODE + | RCUJA_SHADOW_CLEAR_FREE_LOCK); + assert(!ret); + } + + iter_node_flag = parent_node_flag; + /* Remove from parent */ + ret = ja_node_clear_ptr(ja, + node_flag_ptr, /* Pointer to location to nullify */ + &iter_node_flag, /* Old new parent ptr in its parent */ + shadow_nodes[nr_branch - 1], /* of parent */ + n); + if (ret) + goto end; + + dbg_printf("ja_detach_node: publish %p instead of %p\n", + iter_node_flag, *parent_node_flag_ptr); + /* Update address of parent ptr in its parent */ + rcu_assign_pointer(*parent_node_flag_ptr, iter_node_flag); + +end: + for (i = 0; i < nr_shadow; i++) + rcuja_shadow_unlock(shadow_nodes[i]); + return ret; +} + +static +int ja_unchain_node(struct cds_ja *ja, + struct cds_ja_inode_flag *parent_node_flag, + struct cds_hlist_head *head, + struct cds_ja_node *node) +{ + struct cds_ja_shadow_node *shadow_node; + struct cds_hlist_node *hlist_node; + int ret = 0, count = 0; + + shadow_node = rcuja_shadow_lookup_lock(ja->ht, parent_node_flag); + if (!shadow_node) + return -EAGAIN; + /* + * Retry if another thread removed all but one of duplicates + * since check (that was performed without lock). + */ + cds_hlist_for_each_rcu(hlist_node, head, list) { + count++; + } + + if (count == 1) { + ret = -EAGAIN; + goto end; + } + cds_hlist_del_rcu(&node->list); +end: + rcuja_shadow_unlock(shadow_node); + return ret; +} + +/* + * Called with RCU read lock held. + */ +int cds_ja_del(struct cds_ja *ja, uint64_t key, + struct cds_ja_node *node) +{ + unsigned int tree_depth, i; + struct cds_ja_inode_flag *snapshot[JA_MAX_DEPTH]; + struct cds_ja_inode_flag **snapshot_ptr[JA_MAX_DEPTH]; + uint8_t snapshot_n[JA_MAX_DEPTH]; + struct cds_ja_inode_flag *node_flag; + struct cds_ja_inode_flag **prev_node_flag_ptr; + int nr_snapshot; + int ret; + + if (caa_unlikely(key > ja->key_max)) + return -EINVAL; + tree_depth = ja->tree_depth; + +retry: + nr_snapshot = 0; + dbg_printf("cds_ja_del attempt: key %" PRIu64 ", node %p\n", + key, node); + + /* snapshot for level 0 is only for shadow node lookup */ + snapshot_n[0] = 0; + snapshot_n[1] = 0; + snapshot_ptr[nr_snapshot] = NULL; + snapshot[nr_snapshot++] = (struct cds_ja_inode_flag *) &ja->root; + node_flag = rcu_dereference(ja->root); + prev_node_flag_ptr = &ja->root; + + /* Iterate on all internal levels */ + for (i = 1; i < tree_depth; i++) { + uint8_t iter_key; + + dbg_printf("cds_ja_del iter node_flag %p\n", + node_flag); + if (!ja_node_ptr(node_flag)) { + return -ENOENT; + } + iter_key = (uint8_t) (key >> (JA_BITS_PER_BYTE * (tree_depth - i - 1))); + snapshot_n[nr_snapshot + 1] = iter_key; + snapshot_ptr[nr_snapshot] = prev_node_flag_ptr; + snapshot[nr_snapshot++] = node_flag; + node_flag = ja_node_get_nth(node_flag, + &prev_node_flag_ptr, + NULL, + iter_key); + dbg_printf("cds_ja_del iter key lookup %u finds node_flag %p, prev_node_flag_ptr %p\n", + (unsigned int) iter_key, node_flag, + prev_node_flag_ptr); + } + + /* + * We reached bottom of tree, try to find the node we are trying + * to remove. Fail if we cannot find it. + */ + if (!ja_node_ptr(node_flag)) { + dbg_printf("cds_ja_del: no node found for key %" PRIu64 "\n", + key); + return -ENOENT; + } else { + struct cds_hlist_head hlist_head; + struct cds_hlist_node *hlist_node; + struct cds_ja_node *entry, *match = NULL; + int count = 0; + + hlist_head.next = + (struct cds_hlist_node *) ja_node_ptr(node_flag); + cds_hlist_for_each_entry_rcu(entry, + hlist_node, + &hlist_head, + list) { + dbg_printf("cds_ja_del: compare %p with entry %p\n", node, entry); + if (entry == node) + match = entry; + count++; + } + if (!match) { + dbg_printf("cds_ja_del: no node match for node %p key %" PRIu64 "\n", node, key); + return -ENOENT; + } + assert(count > 0); + if (count == 1) { + /* + * Removing last of duplicates. Last snapshot + * does not have a shadow node (external leafs). + */ + snapshot_ptr[nr_snapshot] = prev_node_flag_ptr; + snapshot[nr_snapshot++] = node_flag; + ret = ja_detach_node(ja, snapshot, snapshot_ptr, + snapshot_n, nr_snapshot, key, node); + } else { + ret = ja_unchain_node(ja, snapshot[nr_snapshot - 1], + &hlist_head, match); + } + } + /* + * Explanation of -ENOENT handling: caused by concurrent delete + * between RCU lookup and actual removal. Need to re-do the + * lookup and removal attempt. + */ + if (ret == -EAGAIN || ret == -ENOENT) + goto retry; + return ret; +} + struct cds_ja *_cds_ja_new(unsigned int key_bits, const struct rcu_flavor_struct *flavor) { @@ -1015,13 +1476,13 @@ struct cds_ja *_cds_ja_new(unsigned int key_bits, switch (key_bits) { case 8: - ja->key_max = UINT8_MAX; - break; case 16: - ja->key_max = UINT16_MAX; - break; + case 24: case 32: - ja->key_max = UINT32_MAX; + case 40: + case 48: + case 56: + ja->key_max = (1ULL << key_bits) - 1; break; case 64: ja->key_max = UINT64_MAX; @@ -1042,13 +1503,13 @@ struct cds_ja *_cds_ja_new(unsigned int key_bits, * 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); + (struct cds_ja_inode_flag *) &ja->root, + NULL, ja); if (!root_shadow_node) { ret = -ENOMEM; goto ht_node_error; } - root_shadow_node->is_root = 1; + root_shadow_node->level = 0; return ja; @@ -1062,16 +1523,119 @@ ja_error: return NULL; } +/* + * Called from RCU read-side CS. + */ +__attribute__((visibility("protected"))) +void rcuja_free_all_children(struct cds_ja_shadow_node *shadow_node, + struct cds_ja_inode_flag *node_flag, + void (*free_node_cb)(struct rcu_head *head)) +{ + const struct rcu_flavor_struct *flavor; + unsigned int type_index; + struct cds_ja_inode *node; + const struct cds_ja_type *type; + + flavor = cds_lfht_rcu_flavor(shadow_node->ja->ht); + node = ja_node_ptr(node_flag); + assert(node != NULL); + type_index = ja_node_type(node_flag); + type = &ja_types[type_index]; + + switch (type->type_class) { + case RCU_JA_LINEAR: + { + uint8_t nr_child = + ja_linear_node_get_nr_child(type, node); + unsigned int i; + + for (i = 0; i < nr_child; i++) { + struct cds_ja_inode_flag *iter; + struct cds_hlist_head head; + struct cds_ja_node *entry; + struct cds_hlist_node *pos; + uint8_t v; + + ja_linear_node_get_ith_pos(type, node, i, &v, &iter); + if (!iter) + continue; + head.next = (struct cds_hlist_node *) iter; + cds_hlist_for_each_entry_rcu(entry, pos, &head, list) { + flavor->update_call_rcu(&entry->head, free_node_cb); + } + } + break; + } + case RCU_JA_POOL: + { + unsigned int pool_nr; + + for (pool_nr = 0; pool_nr < (1U << type->nr_pool_order); pool_nr++) { + struct cds_ja_inode *pool = + ja_pool_node_get_ith_pool(type, node, pool_nr); + uint8_t nr_child = + ja_linear_node_get_nr_child(type, pool); + unsigned int j; + + for (j = 0; j < nr_child; j++) { + struct cds_ja_inode_flag *iter; + struct cds_hlist_head head; + struct cds_ja_node *entry; + struct cds_hlist_node *pos; + uint8_t v; + + ja_linear_node_get_ith_pos(type, node, j, &v, &iter); + if (!iter) + continue; + head.next = (struct cds_hlist_node *) iter; + cds_hlist_for_each_entry_rcu(entry, pos, &head, list) { + flavor->update_call_rcu(&entry->head, free_node_cb); + } + } + } + break; + } + case RCU_JA_NULL: + break; + case RCU_JA_PIGEON: + { + uint8_t nr_child; + unsigned int i; + + nr_child = shadow_node->nr_child; + for (i = 0; i < nr_child; i++) { + struct cds_ja_inode_flag *iter; + struct cds_hlist_head head; + struct cds_ja_node *entry; + struct cds_hlist_node *pos; + + iter = ja_pigeon_node_get_ith_pos(type, node, i); + if (!iter) + continue; + head.next = (struct cds_hlist_node *) iter; + cds_hlist_for_each_entry_rcu(entry, pos, &head, list) { + flavor->update_call_rcu(&entry->head, free_node_cb); + } + } + break; + } + default: + assert(0); + } +} + /* * There should be no more concurrent add to the judy array while it is * being destroyed (ensured by the caller). */ -int cds_ja_destroy(struct cds_ja *ja) +int cds_ja_destroy(struct cds_ja *ja, + void (*free_node_cb)(struct rcu_head *head)) { int ret; rcuja_shadow_prune(ja->ht, - RCUJA_SHADOW_CLEAR_FREE_NODE | RCUJA_SHADOW_CLEAR_FREE_LOCK); + RCUJA_SHADOW_CLEAR_FREE_NODE | RCUJA_SHADOW_CLEAR_FREE_LOCK, + free_node_cb); ret = rcuja_delete_ht(ja->ht); if (ret) return ret;