X-Git-Url: http://git.lttng.org./?a=blobdiff_plain;f=urcu%2Frculfhash.h;h=9934422ee9d6e1a4e737da18c73ba14c54dbbff7;hb=HEAD;hp=9208011d900b3770184df8ed2d7d5f2106201a13;hpb=996ff57cc0490bc4ae26de70e9ebe620ff18515f;p=userspace-rcu.git diff --git a/urcu/rculfhash.h b/urcu/rculfhash.h deleted file mode 100644 index 9208011..0000000 --- a/urcu/rculfhash.h +++ /dev/null @@ -1,406 +0,0 @@ -#ifndef _URCU_RCULFHASH_H -#define _URCU_RCULFHASH_H - -/* - * urcu/rculfhash.h - * - * Userspace RCU library - Lock-Free RCU Hash Table - * - * Copyright 2011 - Mathieu Desnoyers - * - * This library is free software; you can redistribute it and/or - * modify it under the terms of the GNU Lesser General Public - * License as published by the Free Software Foundation; either - * version 2.1 of the License, or (at your option) any later version. - * - * This library is distributed in the hope that it will be useful, - * but WITHOUT ANY WARRANTY; without even the implied warranty of - * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU - * Lesser General Public License for more details. - * - * You should have received a copy of the GNU Lesser General Public - * License along with this library; if not, write to the Free Software - * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA - * - * Include this file _after_ including your URCU flavor. - */ - -#include -#include -#include - -#ifdef __cplusplus -extern "C" { -#endif - -/* - * 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 | BUCKET_FLAG | REMOVED_FLAG */ - unsigned long reverse_hash; -} __attribute__((aligned(4))); - -/* cds_lfht_iter: Used to track state while traversing a hash chain. */ -struct cds_lfht_iter { - struct cds_lfht_node *node, *next; -}; - -static inline -struct cds_lfht_node *cds_lfht_iter_get_node(struct cds_lfht_iter *iter) -{ - return iter->node; -} - -struct cds_lfht; - -/* - * Caution ! - * Ensure reader and writer threads are registered as urcu readers. - */ - -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) -{ -} - -/* - * Hash table creation flags. - */ -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(unsigned long init_size, - unsigned long min_alloc_size, - int flags, - void (*cds_lfht_call_rcu)(struct rcu_head *head, - void (*func)(struct rcu_head *head)), - void (*cds_lfht_synchronize_rcu)(void), - void (*cds_lfht_rcu_read_lock)(void), - void (*cds_lfht_rcu_read_unlock)(void), - void (*cds_lfht_rcu_thread_offline)(void), - void (*cds_lfht_rcu_thread_online)(void), - void (*cds_lfht_rcu_register_thread)(void), - void (*cds_lfht_rcu_unregister_thread)(void), - pthread_attr_t *attr); - -/* - * cds_lfht_new - allocate a hash table. - * @init_size: number of nodes to allocate initially. Must be power of two. - * @min_alloc_size: the smallest allocation size to use. 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. - * @attr: optional resize worker thread attributes. NULL for default. - * - * Return NULL on error. - * Note: the RCU flavor must be already included before the hash table header. - * - * The programmer is responsible for ensuring that resize operation has a - * priority equal to hash table updater threads. It should be performed by - * specifying the appropriate priority in the pthread "attr" argument, and, - * for CDS_LFHT_AUTO_RESIZE, by ensuring that call_rcu worker threads also have - * 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 need to be registered RCU read-side threads. - */ -static inline -struct cds_lfht *cds_lfht_new(unsigned long init_size, - unsigned long min_alloc_size, - int flags, - pthread_attr_t *attr) -{ - return _cds_lfht_new(init_size, min_alloc_size, flags, - call_rcu, synchronize_rcu, rcu_read_lock, - rcu_read_unlock, rcu_thread_offline, - rcu_thread_online, rcu_register_thread, - rcu_unregister_thread, attr); -} - -/* - * cds_lfht_destroy - destroy a hash table. - * @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. 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 *split_count_before, - unsigned long *count, - unsigned long *removed, - 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. - * - * 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, unsigned long hash, - cds_lfht_match_fct match, const void *key, - struct cds_lfht_iter *iter); - -/* - * 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. - * Sets *iter->node to NULL if no following node exists with same key. - * RCU read-side lock must be held across cds_lfht_lookup and - * 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. - * - * 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, 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 - * observable in the table. The same guarantee apply for combination of - * 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. - * - * The semantic of replacement vs lookups is the following: if lookups - * are performed between a key unique insertion and its removal, we - * guarantee that the lookups and get next will always find exactly one - * instance of the key if it is replaced concurrently with the lookups. - * - * Providing this semantic allows us to ensure that replacement-only - * schemes will never generate duplicated keys. It also allows us to - * guarantee that a combination of add_replace and add_unique updates - * 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 - * negative value. - * 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). - * - * The semantic of replacement vs lookups is the following: if lookups - * are performed between a key unique insertion and its removal, we - * guarantee that the lookups and get next will always find exactly one - * instance of the key if it is replaced concurrently with the lookups. - * - * Providing this semantic allows us to ensure that replacement-only - * schemes will never generate duplicated keys. It also allows us to - * guarantee that a combination of add_replace and add_unique updates - * will never generate duplicated keys. - */ -int cds_lfht_replace(struct cds_lfht *ht, struct cds_lfht_iter *old_iter, - struct cds_lfht_node *new_node); - -/* - * 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. - * Replacing a NULL node or an already removed node will fail with a - * negative value. - * Node can be looked up with cds_lfht_lookup and cds_lfht_next. - * 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). - */ -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 - -#endif /* _URCU_RCULFHASH_H */