X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=liblttng-ust%2Frculfhash.h;fp=liblttng-ust%2Frculfhash.h;h=0000000000000000000000000000000000000000;hb=9d4c8b2d907edb9ebc9bfde55602598e7ba0832e;hp=9f5016a05ea7c305c39bf1e0b56d6158e241695c;hpb=6ba6fd60507f8e045bdc4f1be14e9d99c6a15f7f;p=lttng-ust.git diff --git a/liblttng-ust/rculfhash.h b/liblttng-ust/rculfhash.h deleted file mode 100644 index 9f5016a0..00000000 --- a/liblttng-ust/rculfhash.h +++ /dev/null @@ -1,458 +0,0 @@ -/* - * SPDX-License-Identifier: LGPL-2.1-or-later - * - * Copyright 2011 Mathieu Desnoyers - * Copyright 2011 Lai Jiangshan - * - * Userspace RCU library - Lock-Free RCU Hash Table - */ - -#ifndef _LTTNG_UST_RCULFHASH_H -#define _LTTNG_UST_RCULFHASH_H - -#include -#include -#include - -#ifdef __cplusplus -extern "C" { -#endif - -struct lttng_ust_lfht; - -/* - * lttng_ust_lfht_node: Contains the next pointers and reverse-hash - * value required for lookup and traversal of the hash table. - * - * struct lttng_ust_lfht_node should be aligned on 8-bytes boundaries because - * the three lower bits are used as flags. It is worth noting that the - * information contained within these three bits could be represented on - * two bits by re-using the same bit for REMOVAL_OWNER_FLAG and - * BUCKET_FLAG. This can be done if we ensure that no iterator nor - * updater check the BUCKET_FLAG after it detects that the REMOVED_FLAG - * is set. Given the minimum size of struct lttng_ust_lfht_node is 8 bytes on - * 32-bit architectures, we choose to go for simplicity and reserve - * three bits. - * - * struct lttng_ust_lfht_node can be embedded into a structure (as a field). - * caa_container_of() can be used to get the structure from the struct - * lttng_ust_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 lttng_ust_lfht APIs. - */ -struct lttng_ust_lfht_node { - struct lttng_ust_lfht_node *next; /* ptr | REMOVAL_OWNER_FLAG | BUCKET_FLAG | REMOVED_FLAG */ - unsigned long reverse_hash; -} __attribute__((aligned(8))); - -/* lttng_ust_lfht_iter: Used to track state while traversing a hash chain. */ -struct lttng_ust_lfht_iter { - struct lttng_ust_lfht_node *node, *next; -}; - -static inline -struct lttng_ust_lfht_node *lttng_ust_lfht_iter_get_node(struct lttng_ust_lfht_iter *iter) -{ - return iter->node; -} - -struct rcu_flavor_struct; - -/* - * Caution ! - * Ensure reader and writer threads are registered as urcu readers. - */ - -typedef int (*lttng_ust_lfht_match_fct)(struct lttng_ust_lfht_node *node, const void *key); - -/* - * lttng_ust_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 lttng_ust_lfht_node_init(struct lttng_ust_lfht_node *node __attribute__((unused))) -{ -} - -/* - * Hash table creation flags. - */ -enum { - LTTNG_UST_LFHT_AUTO_RESIZE = (1U << 0), - LTTNG_UST_LFHT_ACCOUNTING = (1U << 1), -}; - -struct lttng_ust_lfht_mm_type { - struct lttng_ust_lfht *(*alloc_lttng_ust_lfht)(unsigned long min_nr_alloc_buckets, - unsigned long max_nr_buckets); - void (*alloc_bucket_table)(struct lttng_ust_lfht *ht, unsigned long order); - void (*free_bucket_table)(struct lttng_ust_lfht *ht, unsigned long order); - struct lttng_ust_lfht_node *(*bucket_at)(struct lttng_ust_lfht *ht, - unsigned long index); -}; - -extern const struct lttng_ust_lfht_mm_type lttng_ust_lfht_mm_order - __attribute__((visibility("hidden"))); - -extern const struct lttng_ust_lfht_mm_type lttng_ust_lfht_mm_chunk - __attribute__((visibility("hidden"))); - -extern const struct lttng_ust_lfht_mm_type lttng_ust_lfht_mm_mmap - __attribute__((visibility("hidden"))); - -/* - * lttng_ust_lfht_new - allocate a hash table. - * @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, 0 is accepted, means - * "infinite") - * @flags: hash table creation flags (can be combined with bitwise or: '|'). - * 0: no flags. - * LTTNG_UST_LFHT_AUTO_RESIZE: automatically resize hash table. - * LTTNG_UST_LFHT_ACCOUNTING: count the number of node addition - * and removal in the table - * - * Return NULL on error. - * Note: the RCU flavor must be already included before the hash table header. - */ -extern struct lttng_ust_lfht *lttng_ust_lfht_new(unsigned long init_size, - unsigned long min_nr_alloc_buckets, - unsigned long max_nr_buckets, - int flags, - const struct lttng_ust_lfht_mm_type *mm) - __attribute__((visibility("hidden"))); - -/* - * lttng_ust_lfht_destroy - destroy a hash table. - * @ht: the hash table to destroy. - * - * Return 0 on success, negative error value on error. - - * Prior to liburcu 0.10: - * - Threads calling this API need to be registered RCU read-side - * threads. - * - lttng_ust_lfht_destroy should *not* be called from a RCU read-side - * critical section. It should *not* be called from a call_rcu thread - * context neither. - * - * Starting from liburcu 0.10, rculfhash implements its own worker - * thread to handle resize operations, which removes RCU requirements on - * lttng_ust_lfht_destroy. - */ -extern int lttng_ust_lfht_destroy(struct lttng_ust_lfht *ht) - __attribute__((visibility("hidden"))); - -/* - * lttng_ust_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. - * @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. - */ -extern void lttng_ust_lfht_count_nodes(struct lttng_ust_lfht *ht, - long *split_count_before, - unsigned long *count, - long *split_count_after) - __attribute__((visibility("hidden"))); - -/* - * lttng_ust_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. - * This function acts as a rcu_dereference() to read the node pointer. - */ -extern void lttng_ust_lfht_lookup(struct lttng_ust_lfht *ht, unsigned long hash, - lttng_ust_lfht_match_fct match, const void *key, - struct lttng_ust_lfht_iter *iter) - __attribute__((visibility("hidden"))); - -/* - * lttng_ust_lfht_next_duplicate - get the next item with same key, after iterator. - * @ht: the hash table. - * @match: the key match function. - * @key: the current node key. - * @iter: input: current iterator. - * output: node, if found. *iter->node set to NULL if not found. - * - * Uses an iterator initialized by a lookup or traversal. Important: the - * iterator _needs_ to be initialized before calling - * lttng_ust_lfht_next_duplicate. - * 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 lttng_ust_lfht_lookup and - * lttng_ust_lfht_next calls, and also between lttng_ust_lfht_next calls using the - * node returned by a previous lttng_ust_lfht_next. - * Call with rcu_read_lock held. - * Threads calling this API need to be registered RCU read-side threads. - * This function acts as a rcu_dereference() to read the node pointer. - */ -extern void lttng_ust_lfht_next_duplicate(struct lttng_ust_lfht *ht, - lttng_ust_lfht_match_fct match, const void *key, - struct lttng_ust_lfht_iter *iter) - __attribute__((visibility("hidden"))); - -/* - * lttng_ust_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. - * This function acts as a rcu_dereference() to read the node pointer. - */ -extern void lttng_ust_lfht_first(struct lttng_ust_lfht *ht, struct lttng_ust_lfht_iter *iter) - __attribute__((visibility("hidden"))); - -/* - * lttng_ust_lfht_next - get the next node in the table. - * @ht: the hash table. - * @iter: input: current iterator. - * output: next node, if exists. *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. - * This function acts as a rcu_dereference() to read the node pointer. - */ -extern void lttng_ust_lfht_next(struct lttng_ust_lfht *ht, struct lttng_ust_lfht_iter *iter) - __attribute__((visibility("hidden"))); - -/* - * lttng_ust_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. - * This function issues a full memory barrier before and after its - * atomic commit. - */ -extern void lttng_ust_lfht_add(struct lttng_ust_lfht *ht, unsigned long hash, - struct lttng_ust_lfht_node *node) - __attribute__((visibility("hidden"))); - -/* - * lttng_ust_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 - * lttng_ust_lfht_add_unique fails, the node passed as parameter should be - * freed by the caller. In this case, the caller does NOT need to wait - * for a grace period before freeing or re-using the node. - * 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). - * - * Upon success, this function issues a full memory barrier before and - * after its atomic commit. Upon failure, this function acts like a - * simple lookup operation: it acts as a rcu_dereference() to read the - * node pointer. The failure case does not guarantee any other memory - * barrier. - */ -extern struct lttng_ust_lfht_node *lttng_ust_lfht_add_unique(struct lttng_ust_lfht *ht, - unsigned long hash, - lttng_ust_lfht_match_fct match, - const void *key, - struct lttng_ust_lfht_node *node) - __attribute__((visibility("hidden"))); - -/* - * lttng_ust_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 or re-using the memory reserved for the returned node. - * - * The semantic of replacement vs lookups and traversals is the - * following: if lookups and traversals are performed between a key - * unique insertion and its removal, we guarantee that the lookups and - * traversals 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. - * - * This function issues a full memory barrier before and after its - * atomic commit. - */ -extern struct lttng_ust_lfht_node *lttng_ust_lfht_add_replace(struct lttng_ust_lfht *ht, - unsigned long hash, - lttng_ust_lfht_match_fct match, - const void *key, - struct lttng_ust_lfht_node *node) - __attribute__((visibility("hidden"))); - -/* - * lttng_ust_lfht_replace - replace a node pointed to by iter within hash table. - * @ht: the hash table. - * @old_iter: the iterator position of the node to replace. - * @hash: the node's hash. - * @match: the key match function. - * @key: the node's key. - * @new_node: the new node to use as replacement. - * - * Return 0 if replacement is successful, negative value otherwise. - * Replacing a NULL old node or an already removed node will fail with - * -ENOENT. - * If the hash or value of the node to replace and the new node differ, - * this function returns -EINVAL without proceeding to the replacement. - * Old node can be looked up with lttng_ust_lfht_lookup and lttng_ust_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 or re-using the memory reserved for the old node (which can - * be accessed with lttng_ust_lfht_iter_get_node). - * - * The semantic of replacement vs lookups is the same as - * lttng_ust_lfht_add_replace(). - * - * Upon success, this function issues a full memory barrier before and - * after its atomic commit. Upon failure, this function does not issue - * any memory barrier. - */ -extern int lttng_ust_lfht_replace(struct lttng_ust_lfht *ht, - struct lttng_ust_lfht_iter *old_iter, - unsigned long hash, - lttng_ust_lfht_match_fct match, - const void *key, - struct lttng_ust_lfht_node *new_node) - __attribute__((visibility("hidden"))); - -/* - * lttng_ust_lfht_del - remove node pointed to by iterator from hash table. - * @ht: the hash table. - * @node: the node to delete. - * - * Return 0 if the node is successfully removed, negative value - * otherwise. - * Deleting a NULL node or an already removed node will fail with a - * negative value. - * Node can be looked up with lttng_ust_lfht_lookup and lttng_ust_lfht_next, - * followed by use of lttng_ust_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 or re-using the memory reserved for old node (which can be - * accessed with lttng_ust_lfht_iter_get_node). - * Upon success, this function issues a full memory barrier before and - * after its atomic commit. Upon failure, this function does not issue - * any memory barrier. - */ -extern int lttng_ust_lfht_del(struct lttng_ust_lfht *ht, struct lttng_ust_lfht_node *node) - __attribute__((visibility("hidden"))); - -/* - * lttng_ust_lfht_is_node_deleted - query whether a node is removed from hash table. - * - * Return non-zero if the node is deleted from the hash table, 0 - * otherwise. - * Node can be looked up with lttng_ust_lfht_lookup and lttng_ust_lfht_next, - * followed by use of lttng_ust_lfht_iter_get_node. - * RCU read-side lock must be held between lookup and call to this - * function. - * Call with rcu_read_lock held. - * Threads calling this API need to be registered RCU read-side threads. - * This function does not issue any memory barrier. - */ -extern int lttng_ust_lfht_is_node_deleted(const struct lttng_ust_lfht_node *node) - __attribute__((visibility("hidden"))); - -/* - * lttng_ust_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. - * This function does not (necessarily) issue memory barriers. - * lttng_ust_lfht_resize should *not* be called from a RCU read-side critical - * section. - */ -extern void lttng_ust_lfht_resize(struct lttng_ust_lfht *ht, unsigned long new_size) - __attribute__((visibility("hidden"))); - -/* - * Note: it is safe to perform element removal (del), replacement, or - * any hash table update operation during any of the following hash - * table traversals. - * These functions act as rcu_dereference() to read the node pointers. - */ -#define lttng_ust_lfht_for_each(ht, iter, node) \ - for (lttng_ust_lfht_first(ht, iter), \ - node = lttng_ust_lfht_iter_get_node(iter); \ - node != NULL; \ - lttng_ust_lfht_next(ht, iter), \ - node = lttng_ust_lfht_iter_get_node(iter)) - -#define lttng_ust_lfht_for_each_duplicate(ht, hash, match, key, iter, node) \ - for (lttng_ust_lfht_lookup(ht, hash, match, key, iter), \ - node = lttng_ust_lfht_iter_get_node(iter); \ - node != NULL; \ - lttng_ust_lfht_next_duplicate(ht, match, key, iter), \ - node = lttng_ust_lfht_iter_get_node(iter)) - -#define lttng_ust_lfht_for_each_entry(ht, iter, pos, member) \ - for (lttng_ust_lfht_first(ht, iter), \ - pos = caa_container_of(lttng_ust_lfht_iter_get_node(iter), \ - __typeof__(*(pos)), member); \ - lttng_ust_lfht_iter_get_node(iter) != NULL; \ - lttng_ust_lfht_next(ht, iter), \ - pos = caa_container_of(lttng_ust_lfht_iter_get_node(iter), \ - __typeof__(*(pos)), member)) - -#define lttng_ust_lfht_for_each_entry_duplicate(ht, hash, match, key, \ - iter, pos, member) \ - for (lttng_ust_lfht_lookup(ht, hash, match, key, iter), \ - pos = caa_container_of(lttng_ust_lfht_iter_get_node(iter), \ - __typeof__(*(pos)), member); \ - lttng_ust_lfht_iter_get_node(iter) != NULL; \ - lttng_ust_lfht_next_duplicate(ht, match, key, iter), \ - pos = caa_container_of(lttng_ust_lfht_iter_get_node(iter), \ - __typeof__(*(pos)), member)) - -#ifdef __cplusplus -} -#endif - -#endif /* _LTTNG_UST_RCULFHASH_H */