+++ /dev/null
-#ifndef _URCU_RCULFHASH_H
-#define _URCU_RCULFHASH_H
-
-/*
- * urcu/rculfhash.h
- *
- * Userspace RCU library - Lock-Free RCU Hash Table
- *
- * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
- *
- * 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 <stdint.h>
-#include <urcu-call-rcu.h>
-
-#ifdef __cplusplus
-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 internal pointers and reverse-hash
- * value required for lookup and traversal of the hash table.
- */
-struct _cds_lfht_node {
- struct cds_lfht_node *next; /* ptr | DUMMY_FLAG | REMOVED_FLAG */
- unsigned long reverse_hash;
-} __attribute__((aligned(4)));
-
-/*
- * cds_lfht_node: Contains the full key and length required to check for
- * an actual match, and also contains an rcu_head structure that is used
- * by RCU to track a node through a given RCU grace period. There is an
- * instance of _cds_lfht_node enclosed as a field within each
- * _cds_lfht_node structure.
- *
- * 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.
- */
-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;
-};
-
-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 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);
-
-/*
- * cds_lfht_node_init - initialize a hash table node
- */
-static inline
-void cds_lfht_node_init(struct cds_lfht_node *node, void *key,
- size_t key_len)
-{
- node->key = key;
- node->key_len = key_len;
-}
-
-/*
- * 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(cds_lfht_hash_fct hash_fct,
- cds_lfht_compare_fct compare_fct,
- unsigned long hash_seed,
- 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.
- * @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.
- * @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(cds_lfht_hash_fct hash_fct,
- cds_lfht_compare_fct compare_fct,
- unsigned long hash_seed,
- unsigned long init_size,
- unsigned long min_alloc_size,
- int flags,
- pthread_attr_t *attr)
-{
- return _cds_lfht_new(hash_fct, compare_fct, hash_seed,
- 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.
- *
- * 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,
- struct cds_lfht_iter *iter);
-
-/*
- * cds_lfht_next_duplicate - get the next item with same key (after a lookup).
- *
- * 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, struct cds_lfht_iter *iter);
-
-/*
- * cds_lfht_first - get the first node in the table.
- *
- * 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.
- *
- * 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.
- *
- * 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);
-
-/*
- * cds_lfht_add_unique - add a node to hash table, if key is not present.
- *
- * 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,
- struct cds_lfht_node *node);
-
-/*
- * cds_lfht_add_replace - replace or add a node within hash table.
- *
- * 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,
- struct cds_lfht_node *node);
-
-/*
- * cds_lfht_replace - replace a node pointer to by iter within hash table.
- *
- * 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.
- *
- * 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
- * @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, match, hash, key, iter, node) \
- for (cds_lfht_lookup(ht, match, hash, 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, match, hash, key, \
- iter, pos, member) \
-for (cds_lfht_lookup(ht, match, hash, 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 */
projects / lttng-tools.git / blobdiff