X-Git-Url: http://git.liburcu.org/?p=urcu.git;a=blobdiff_plain;f=urcu%2Frculfhash.h;h=6953ad12499b515819b73e56808106fdf55926e1;hp=860ef3d1c2d05e3516ec4a8849c9d47b39f1371f;hb=747d725c1dd45d5072e0e411642c4d5c6403b4be;hpb=14b2b8b8b23d8bf89411ed532cbf9011041981c6 diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h index 860ef3d..6953ad1 100644 --- a/urcu/rculfhash.h +++ b/urcu/rculfhash.h @@ -7,6 +7,7 @@ * Userspace RCU library - Lock-Free RCU Hash Table * * Copyright 2011 - Mathieu Desnoyers + * Copyright 2011 - Lai Jiangshan * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public @@ -26,6 +27,7 @@ */ #include +#include #include #ifdef __cplusplus @@ -33,24 +35,26 @@ extern "C" { #endif /* - * struct cds_lfht_node and struct _cds_lfht_node should be aligned on - * 4-bytes boundaries because the two lower bits are used as flags. + * cds_lfht_node: Contains the next pointers and reverse-hash + * value required for lookup and traversal of the hash table. + * + * struct cds_lfht_node should be aligned on 4-bytes boundaries because + * the two lower bits are used as flags. + * + * struct cds_lfht_node can be embedded into a structure (as a field). + * caa_container_of() can be used to get the structure from the struct + * cds_lfht_node after a lookup. + * + * The structure which embeds it typically holds the key (or key-value + * pair) of the object. The caller code is responsible for calculation + * of the hash value for cds_lfht APIs. */ - -struct _cds_lfht_node { - struct cds_lfht_node *next; /* ptr | DUMMY_FLAG | REMOVED_FLAG */ +struct cds_lfht_node { + struct cds_lfht_node *next; /* ptr | BUCKET_FLAG | REMOVED_FLAG */ unsigned long reverse_hash; } __attribute__((aligned(4))); -struct cds_lfht_node { - /* cache-hot for iteration */ - struct _cds_lfht_node p; /* needs to be first field */ - void *key; - unsigned int key_len; - /* cache-cold for iteration */ - struct rcu_head head; -}; - +/* cds_lfht_iter: Used to track state while traversing a hash chain. */ struct cds_lfht_iter { struct cds_lfht_node *node, *next; }; @@ -68,20 +72,18 @@ struct cds_lfht; * Ensure reader and writer threads are registered as urcu readers. */ -typedef unsigned long (*cds_lfht_hash_fct)(void *key, size_t length, - unsigned long seed); -typedef unsigned long (*cds_lfht_compare_fct)(void *key1, size_t key1_len, - void *key2, size_t key2_len); +typedef int (*cds_lfht_match_fct)(struct cds_lfht_node *node, const void *key); /* * cds_lfht_node_init - initialize a hash table node + * @node: the node to initialize. + * + * This function is kept to be eventually used for debugging purposes + * (detection of memory corruption). */ static inline -void cds_lfht_node_init(struct cds_lfht_node *node, void *key, - size_t key_len) +void cds_lfht_node_init(struct cds_lfht_node *node) { - node->key = key; - node->key_len = key_len; } /* @@ -89,15 +91,15 @@ void cds_lfht_node_init(struct cds_lfht_node *node, void *key, */ enum { CDS_LFHT_AUTO_RESIZE = (1U << 0), + CDS_LFHT_ACCOUNTING = (1U << 1), }; /* * _cds_lfht_new - API used by cds_lfht_new wrapper. Do not use directly. */ -struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct, - cds_lfht_compare_fct compare_fct, - unsigned long hash_seed, - unsigned long init_size, +struct cds_lfht *_cds_lfht_new(unsigned long init_size, + unsigned long min_nr_alloc_buckets, + unsigned long max_nr_buckets, int flags, void (*cds_lfht_call_rcu)(struct rcu_head *head, void (*func)(struct rcu_head *head)), @@ -112,13 +114,16 @@ struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct, /* * cds_lfht_new - allocate a hash table. - * @hash_fct: the hashing function. - * @compare_fct: the key comparison function. - * @hash_seed: the seed for hash function. - * @init_size: number of nodes to allocate initially. Must be power of two. + * @init_size: number of buckets to allocate initially. Must be power of two. + * @min_nr_alloc_buckets: the minimum number of allocated buckets. + * (must be power of two) + * @max_nr_buckets: the maximum number of hash table buckets allowed. + * (must be power of two) * @flags: hash table creation flags (can be combined with bitwise or: '|'). * 0: no flags. * CDS_LFHT_AUTO_RESIZE: automatically resize hash table. + * CDS_LFHT_ACCOUNTING: count the number of node addition + * and removal in the table * @attr: optional resize worker thread attributes. NULL for default. * * Return NULL on error. @@ -131,17 +136,17 @@ struct cds_lfht *_cds_lfht_new(cds_lfht_hash_fct hash_fct, * this priority level. Having lower priority for call_rcu and resize threads * does not pose any correctness issue, but the resize operations could be * starved by updates, thus leading to long hash table bucket chains. + * Threads calling this API are NOT required to be registered RCU read-side + * threads. It can be called very early.(before rcu is initialized ...etc.) */ static inline -struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct, - cds_lfht_compare_fct compare_fct, - unsigned long hash_seed, - unsigned long init_size, +struct cds_lfht *cds_lfht_new(unsigned long init_size, + unsigned long min_nr_alloc_buckets, + unsigned long max_nr_buckets, int flags, pthread_attr_t *attr) { - return _cds_lfht_new(hash_fct, compare_fct, hash_seed, - init_size, flags, + return _cds_lfht_new(init_size, min_nr_alloc_buckets, max_nr_buckets, flags, call_rcu, synchronize_rcu, rcu_read_lock, rcu_read_unlock, rcu_thread_offline, rcu_thread_online, rcu_register_thread, @@ -153,34 +158,52 @@ struct cds_lfht *cds_lfht_new(cds_lfht_hash_fct hash_fct, * @ht: the hash table to destroy. * @attr: (output) resize worker thread attributes, as received by cds_lfht_new. * The caller will typically want to free this pointer if dynamically - * allocated. + * allocated. The attr point can be NULL if the caller does not + * need to be informed of the value passed to cds_lfht_new(). * * Return 0 on success, negative error value on error. + * Threads calling this API need to be registered RCU read-side threads. */ int cds_lfht_destroy(struct cds_lfht *ht, pthread_attr_t **attr); /* * cds_lfht_count_nodes - count the number of nodes in the hash table. + * @ht: the hash table. + * @split_count_before: Sample the node count split-counter before traversal. + * @count: Traverse the hash table, count the number of nodes observed. + * @removed: Number of logically removed nodes observed during traversal. + * @split_count_after: Sample the node count split-counter after traversal. * * Call with rcu_read_lock held. + * Threads calling this API need to be registered RCU read-side threads. */ void cds_lfht_count_nodes(struct cds_lfht *ht, - long *approx_before, + long *split_count_before, unsigned long *count, unsigned long *removed, - long *approx_after); + long *split_count_after); /* * cds_lfht_lookup - lookup a node by key. + * @ht: the hash table. + * @hash: the key hash. + * @match: the key match function. + * @key: the current node key. + * @iter: Node, if found (output). *iter->node set to NULL if not found. * - * Output in "*iter". *iter->node set to NULL if not found. * Call with rcu_read_lock held. + * Threads calling this API need to be registered RCU read-side threads. */ -void cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len, +void cds_lfht_lookup(struct cds_lfht *ht, unsigned long hash, + cds_lfht_match_fct match, const void *key, struct cds_lfht_iter *iter); /* - * cds_lfht_next - get the next item with same key (after a lookup). + * cds_lfht_next_duplicate - get the next item with same key (after a lookup). + * @ht: the hash table. + * @match: the key match function. + * @key: the current node key. + * @iter: Node, if found (output). *iter->node set to NULL if not found. * * Uses an iterator initialized by a lookup. * Sets *iter-node to the following node with same key. @@ -189,25 +212,62 @@ void cds_lfht_lookup(struct cds_lfht *ht, void *key, size_t key_len, * cds_lfht_next calls, and also between cds_lfht_next calls using the * node returned by a previous cds_lfht_next. * Call with rcu_read_lock held. + * Threads calling this API need to be registered RCU read-side threads. + */ +void cds_lfht_next_duplicate(struct cds_lfht *ht, + cds_lfht_match_fct match, const void *key, + struct cds_lfht_iter *iter); + +/* + * cds_lfht_first - get the first node in the table. + * @ht: the hash table. + * @iter: First node, if exists (output). *iter->node set to NULL if not found. + * + * Output in "*iter". *iter->node set to NULL if table is empty. + * Call with rcu_read_lock held. + * Threads calling this API need to be registered RCU read-side threads. + */ +void cds_lfht_first(struct cds_lfht *ht, struct cds_lfht_iter *iter); + +/* + * cds_lfht_next - get the next node in the table. + * @ht: the hash table. + * @iter: Next node, if exists (output). *iter->node set to NULL if not found. + * + * Input/Output in "*iter". *iter->node set to NULL if *iter was + * pointing to the last table node. + * Call with rcu_read_lock held. + * Threads calling this API need to be registered RCU read-side threads. */ void cds_lfht_next(struct cds_lfht *ht, struct cds_lfht_iter *iter); /* * cds_lfht_add - add a node to the hash table. + * @ht: the hash table. + * @hash: the key hash. + * @node: the node to add. * - * Call with rcu_read_lock held. * This function supports adding redundant keys into the table. + * Call with rcu_read_lock held. + * Threads calling this API need to be registered RCU read-side threads. */ -void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node); +void cds_lfht_add(struct cds_lfht *ht, unsigned long hash, + struct cds_lfht_node *node); /* * cds_lfht_add_unique - add a node to hash table, if key is not present. + * @ht: the hash table. + * @hash: the node's hash. + * @match: the key match function. + * @key: the node's key. + * @node: the node to try adding. * * Return the node added upon success. * Return the unique node already present upon failure. If * cds_lfht_add_unique fails, the node passed as parameter should be * freed by the caller. * Call with rcu_read_lock held. + * Threads calling this API need to be registered RCU read-side threads. * * The semantic of this function is that if only this function is used * to add keys into the table, no duplicated keys should ever be @@ -215,15 +275,24 @@ void cds_lfht_add(struct cds_lfht *ht, struct cds_lfht_node *node); * add_unique and add_replace (see below). */ struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, + unsigned long hash, + cds_lfht_match_fct match, + const void *key, struct cds_lfht_node *node); /* * cds_lfht_add_replace - replace or add a node within hash table. + * @ht: the hash table. + * @hash: the node's hash. + * @match: the key match function. + * @key: the node's key. + * @node: the node to add. * * Return the node replaced upon success. If no node matching the key * was present, return NULL, which also means the operation succeeded. * This replacement operation should never fail. * Call with rcu_read_lock held. + * Threads calling this API need to be registered RCU read-side threads. * After successful replacement, a grace period must be waited for before * freeing the memory reserved for the returned node. * @@ -238,10 +307,16 @@ struct cds_lfht_node *cds_lfht_add_unique(struct cds_lfht *ht, * will never generate duplicated keys. */ struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht, + unsigned long hash, + cds_lfht_match_fct match, + const void *key, struct cds_lfht_node *node); /* * cds_lfht_replace - replace a node pointer to by iter within hash table. + * @ht: the hash table. + * @old_iter: the iterator position of the node to replace. + * @now_node: the new node to try using for replacement. * * Return 0 if replacement is successful, negative value otherwise. * Replacing a NULL old node or an already removed node will fail with a @@ -249,6 +324,7 @@ struct cds_lfht_node *cds_lfht_add_replace(struct cds_lfht *ht, * Old node can be looked up with cds_lfht_lookup and cds_lfht_next. * RCU read-side lock must be held between lookup and replacement. * Call with rcu_read_lock held. + * Threads calling this API need to be registered RCU read-side threads. * After successful replacement, a grace period must be waited for before * freeing the memory reserved for the old node (which can be accessed * with cds_lfht_iter_get_node). @@ -268,6 +344,8 @@ int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter, /* * cds_lfht_del - remove node pointed to by iterator from hash table. + * @ht: the hash table. + * @iter: the iterator position of the node to delete. * * Return 0 if the node is successfully removed, negative value * otherwise. @@ -277,6 +355,7 @@ int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter, * cds_lfht_iter_get_node. * RCU read-side lock must be held between lookup and removal. * Call with rcu_read_lock held. + * Threads calling this API need to be registered RCU read-side threads. * After successful removal, a grace period must be waited for before * freeing the memory reserved for old node (which can be accessed with * cds_lfht_iter_get_node). @@ -285,10 +364,50 @@ int cds_lfht_del(struct cds_lfht *ht, struct cds_lfht_iter *iter); /* * cds_lfht_resize - Force a hash table resize + * @ht: the hash table. * @new_size: update to this hash table size. + * + * Threads calling this API need to be registered RCU read-side threads. */ void cds_lfht_resize(struct cds_lfht *ht, unsigned long new_size); +/* + * Note: cds_lfht_for_each are safe for element removal during + * iteration. + */ +#define cds_lfht_for_each(ht, iter, node) \ + for (cds_lfht_first(ht, iter), \ + node = cds_lfht_iter_get_node(iter); \ + node != NULL; \ + cds_lfht_next(ht, iter), \ + node = cds_lfht_iter_get_node(iter)) + +#define cds_lfht_for_each_duplicate(ht, hash, match, key, iter, node) \ + for (cds_lfht_lookup(ht, hash, match, key, iter), \ + node = cds_lfht_iter_get_node(iter); \ + node != NULL; \ + cds_lfht_next_duplicate(ht, match, key, iter), \ + node = cds_lfht_iter_get_node(iter)) + +#define cds_lfht_for_each_entry(ht, iter, pos, member) \ + for (cds_lfht_first(ht, iter), \ + pos = caa_container_of(cds_lfht_iter_get_node(iter), \ + typeof(*(pos)), member); \ + &(pos)->member != NULL; \ + cds_lfht_next(ht, iter), \ + pos = caa_container_of(cds_lfht_iter_get_node(iter), \ + typeof(*(pos)), member)) + +#define cds_lfht_for_each_entry_duplicate(ht, hash, match, key, \ + iter, pos, member) \ + for (cds_lfht_lookup(ht, hash, match, key, iter), \ + pos = caa_container_of(cds_lfht_iter_get_node(iter), \ + typeof(*(pos)), member); \ + &(pos)->member != NULL; \ + cds_lfht_next_duplicate(ht, match, key, iter), \ + pos = caa_container_of(cds_lfht_iter_get_node(iter), \ + typeof(*(pos)), member)) + #ifdef __cplusplus } #endif