e605a1d36c
Add lock-free read-write concurrency. This is achieved by the following changes. 1) Add memory ordering to avoid race conditions. The only race condition that can occur is - using the key store element before the key write is completed. Hence, while inserting the element the release memory order is used. Any other race condition is caught by the key comparison. Memory orderings are added only where needed. For ex: reads in the writer's context do not need memory ordering as there is a single writer. key_idx in the bucket entry and pdata in the key store element are used for synchronisation. key_idx is used to release an inserted entry in the bucket to the reader. Use of pdata for synchronisation is required due to updation of an existing entry where-in only the pdata is updated without updating key_idx. 2) Reader-writer concurrency issue, caused by moving the keys to their alternative locations during key insert, is solved by introducing a global counter(tbl_chng_cnt) indicating a change in table. 3) Add the flag to enable reader-writer concurrency during run time. Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com> Reviewed-by: Gavin Hu <gavin.hu@arm.com> Reviewed-by: Ola Liljedahl <ola.liljedahl@arm.com> Reviewed-by: Steve Capper <steve.capper@arm.com> Reviewed-by: Yipeng Wang <yipeng1.wang@intel.com> Acked-by: Bruce Richardson <bruce.richardson@intel.com>
552 lines
18 KiB
C
552 lines
18 KiB
C
/* SPDX-License-Identifier: BSD-3-Clause
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* Copyright(c) 2010-2015 Intel Corporation
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*/
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#ifndef _RTE_HASH_H_
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#define _RTE_HASH_H_
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/**
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* @file
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*
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* RTE Hash Table
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*/
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#include <stdint.h>
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#include <stddef.h>
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#include <rte_compat.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/** Maximum size of hash table that can be created. */
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#define RTE_HASH_ENTRIES_MAX (1 << 30)
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/** Maximum number of characters in hash name.*/
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#define RTE_HASH_NAMESIZE 32
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/** Maximum number of keys that can be searched for using rte_hash_lookup_bulk. */
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#define RTE_HASH_LOOKUP_BULK_MAX 64
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#define RTE_HASH_LOOKUP_MULTI_MAX RTE_HASH_LOOKUP_BULK_MAX
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/** Enable Hardware transactional memory support. */
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#define RTE_HASH_EXTRA_FLAGS_TRANS_MEM_SUPPORT 0x01
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/** Default behavior of insertion, single writer/multi writer */
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#define RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD 0x02
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/** Flag to support reader writer concurrency */
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#define RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY 0x04
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/** Flag to indicate the extendabe bucket table feature should be used */
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#define RTE_HASH_EXTRA_FLAGS_EXT_TABLE 0x08
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/** Flag to disable freeing of key index on hash delete.
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* Refer to rte_hash_del_xxx APIs for more details.
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* This is enabled by default when RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF
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* is enabled.
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*/
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#define RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL 0x10
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/** Flag to support lock free reader writer concurrency. Both single writer
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* and multi writer use cases are supported.
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* Currently, extendable bucket table feature is not supported with
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* this feature.
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*/
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#define RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF 0x20
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/**
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* The type of hash value of a key.
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* It should be a value of at least 32bit with fully random pattern.
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*/
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typedef uint32_t hash_sig_t;
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/** Type of function that can be used for calculating the hash value. */
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typedef uint32_t (*rte_hash_function)(const void *key, uint32_t key_len,
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uint32_t init_val);
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/** Type of function used to compare the hash key. */
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typedef int (*rte_hash_cmp_eq_t)(const void *key1, const void *key2, size_t key_len);
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/**
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* Parameters used when creating the hash table.
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*/
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struct rte_hash_parameters {
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const char *name; /**< Name of the hash. */
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uint32_t entries; /**< Total hash table entries. */
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uint32_t reserved; /**< Unused field. Should be set to 0 */
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uint32_t key_len; /**< Length of hash key. */
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rte_hash_function hash_func; /**< Primary Hash function used to calculate hash. */
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uint32_t hash_func_init_val; /**< Init value used by hash_func. */
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int socket_id; /**< NUMA Socket ID for memory. */
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uint8_t extra_flag; /**< Indicate if additional parameters are present. */
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};
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/** @internal A hash table structure. */
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struct rte_hash;
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/**
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* Create a new hash table.
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*
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* @param params
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* Parameters used to create and initialise the hash table.
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* @return
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* Pointer to hash table structure that is used in future hash table
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* operations, or NULL on error, with error code set in rte_errno.
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* Possible rte_errno errors include:
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* - E_RTE_NO_CONFIG - function could not get pointer to rte_config structure
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* - E_RTE_SECONDARY - function was called from a secondary process instance
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* - ENOENT - missing entry
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* - EINVAL - invalid parameter passed to function
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* - ENOSPC - the maximum number of memzones has already been allocated
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* - EEXIST - a memzone with the same name already exists
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* - ENOMEM - no appropriate memory area found in which to create memzone
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*/
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struct rte_hash *
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rte_hash_create(const struct rte_hash_parameters *params);
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/**
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* Set a new hash compare function other than the default one.
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*
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* @note Function pointer does not work with multi-process, so do not use it
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* in multi-process mode.
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*
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* @param h
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* Hash table for which the function is to be changed
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* @param func
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* New compare function
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*/
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void rte_hash_set_cmp_func(struct rte_hash *h, rte_hash_cmp_eq_t func);
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/**
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* Find an existing hash table object and return a pointer to it.
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*
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* @param name
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* Name of the hash table as passed to rte_hash_create()
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* @return
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* Pointer to hash table or NULL if object not found
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* with rte_errno set appropriately. Possible rte_errno values include:
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* - ENOENT - value not available for return
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*/
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struct rte_hash *
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rte_hash_find_existing(const char *name);
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/**
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* De-allocate all memory used by hash table.
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* @param h
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* Hash table to free
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*/
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void
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rte_hash_free(struct rte_hash *h);
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/**
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* Reset all hash structure, by zeroing all entries.
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* When RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF is enabled,
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* it is application's responsibility to make sure that
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* none of the readers are referencing the hash table
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* while calling this API.
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*
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* @param h
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* Hash table to reset
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*/
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void
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rte_hash_reset(struct rte_hash *h);
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/**
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* Return the number of keys in the hash table
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* @param h
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* Hash table to query from
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* @return
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* - -EINVAL if parameters are invalid
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* - A value indicating how many keys were inserted in the table.
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*/
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int32_t
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rte_hash_count(const struct rte_hash *h);
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/**
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* Add a key-value pair to an existing hash table.
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* This operation is not multi-thread safe
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* and should only be called from one thread by default.
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* Thread safety can be enabled by setting flag during
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* table creation.
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* If the key exists already in the table, this API updates its value
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* with 'data' passed in this API. It is the responsibility of
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* the application to manage any memory associated with the old value.
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* The readers might still be using the old value even after this API
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* has returned.
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*
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* @param h
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* Hash table to add the key to.
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* @param key
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* Key to add to the hash table.
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* @param data
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* Data to add to the hash table.
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* @return
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* - 0 if added successfully
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* - -EINVAL if the parameters are invalid.
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* - -ENOSPC if there is no space in the hash for this key.
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*/
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int
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rte_hash_add_key_data(const struct rte_hash *h, const void *key, void *data);
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/**
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* Add a key-value pair with a pre-computed hash value
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* to an existing hash table.
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* This operation is not multi-thread safe
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* and should only be called from one thread by default.
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* Thread safety can be enabled by setting flag during
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* table creation.
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* If the key exists already in the table, this API updates its value
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* with 'data' passed in this API. It is the responsibility of
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* the application to manage any memory associated with the old value.
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* The readers might still be using the old value even after this API
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* has returned.
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*
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* @param h
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* Hash table to add the key to.
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* @param key
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* Key to add to the hash table.
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* @param sig
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* Precomputed hash value for 'key'
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* @param data
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* Data to add to the hash table.
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* @return
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* - 0 if added successfully
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* - -EINVAL if the parameters are invalid.
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* - -ENOSPC if there is no space in the hash for this key.
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*/
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int32_t
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rte_hash_add_key_with_hash_data(const struct rte_hash *h, const void *key,
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hash_sig_t sig, void *data);
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/**
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* Add a key to an existing hash table. This operation is not multi-thread safe
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* and should only be called from one thread by default.
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* Thread safety can be enabled by setting flag during
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* table creation.
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*
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* @param h
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* Hash table to add the key to.
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* @param key
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* Key to add to the hash table.
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* @return
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* - -EINVAL if the parameters are invalid.
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* - -ENOSPC if there is no space in the hash for this key.
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* - A positive value that can be used by the caller as an offset into an
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* array of user data. This value is unique for this key.
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*/
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int32_t
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rte_hash_add_key(const struct rte_hash *h, const void *key);
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/**
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* Add a key to an existing hash table.
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* This operation is not multi-thread safe
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* and should only be called from one thread by default.
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* Thread safety can be enabled by setting flag during
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* table creation.
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*
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* @param h
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* Hash table to add the key to.
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* @param key
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* Key to add to the hash table.
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* @param sig
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* Precomputed hash value for 'key'.
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* @return
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* - -EINVAL if the parameters are invalid.
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* - -ENOSPC if there is no space in the hash for this key.
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* - A positive value that can be used by the caller as an offset into an
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* array of user data. This value is unique for this key.
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*/
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int32_t
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rte_hash_add_key_with_hash(const struct rte_hash *h, const void *key, hash_sig_t sig);
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/**
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* Remove a key from an existing hash table.
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* This operation is not multi-thread safe
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* and should only be called from one thread by default.
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* Thread safety can be enabled by setting flag during
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* table creation.
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* If RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL or
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* RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF is enabled,
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* the key index returned by rte_hash_add_key_xxx APIs will not be
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* freed by this API. rte_hash_free_key_with_position API must be called
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* additionally to free the index associated with the key.
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* rte_hash_free_key_with_position API should be called after all
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* the readers have stopped referencing the entry corresponding to
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* this key. RCU mechanisms could be used to determine such a state.
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*
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* @param h
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* Hash table to remove the key from.
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* @param key
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* Key to remove from the hash table.
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* @return
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* - -EINVAL if the parameters are invalid.
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* - -ENOENT if the key is not found.
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* - A positive value that can be used by the caller as an offset into an
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* array of user data. This value is unique for this key, and is the same
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* value that was returned when the key was added.
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*/
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int32_t
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rte_hash_del_key(const struct rte_hash *h, const void *key);
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/**
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* Remove a key from an existing hash table.
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* This operation is not multi-thread safe
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* and should only be called from one thread by default.
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* Thread safety can be enabled by setting flag during
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* table creation.
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* If RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL or
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* RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF is enabled,
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* the key index returned by rte_hash_add_key_xxx APIs will not be
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* freed by this API. rte_hash_free_key_with_position API must be called
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* additionally to free the index associated with the key.
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* rte_hash_free_key_with_position API should be called after all
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* the readers have stopped referencing the entry corresponding to
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* this key. RCU mechanisms could be used to determine such a state.
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*
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* @param h
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* Hash table to remove the key from.
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* @param key
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* Key to remove from the hash table.
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* @param sig
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* Precomputed hash value for 'key'.
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* @return
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* - -EINVAL if the parameters are invalid.
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* - -ENOENT if the key is not found.
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* - A positive value that can be used by the caller as an offset into an
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* array of user data. This value is unique for this key, and is the same
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* value that was returned when the key was added.
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*/
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int32_t
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rte_hash_del_key_with_hash(const struct rte_hash *h, const void *key, hash_sig_t sig);
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/**
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* Find a key in the hash table given the position.
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* This operation is multi-thread safe with regarding to other lookup threads.
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* Read-write concurrency can be enabled by setting flag during
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* table creation.
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*
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* @param h
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* Hash table to get the key from.
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* @param position
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* Position returned when the key was inserted.
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* @param key
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* Output containing a pointer to the key
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* @return
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* - 0 if retrieved successfully
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* - -EINVAL if the parameters are invalid.
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* - -ENOENT if no valid key is found in the given position.
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*/
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int
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rte_hash_get_key_with_position(const struct rte_hash *h, const int32_t position,
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void **key);
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/**
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* @warning
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* @b EXPERIMENTAL: this API may change without prior notice
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*
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* Free a hash key in the hash table given the position
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* of the key. This operation is not multi-thread safe and should
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* only be called from one thread by default. Thread safety
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* can be enabled by setting flag during table creation.
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* If RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL or
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* RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF is enabled,
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* the key index returned by rte_hash_del_key_xxx APIs must be freed
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* using this API. This API should be called after all the readers
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* have stopped referencing the entry corresponding to this key.
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* RCU mechanisms could be used to determine such a state.
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* This API does not validate if the key is already freed.
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*
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* @param h
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* Hash table to free the key from.
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* @param position
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* Position returned when the key was deleted.
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* @return
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* - 0 if freed successfully
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* - -EINVAL if the parameters are invalid.
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*/
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int __rte_experimental
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rte_hash_free_key_with_position(const struct rte_hash *h,
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const int32_t position);
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/**
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* Find a key-value pair in the hash table.
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* This operation is multi-thread safe with regarding to other lookup threads.
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* Read-write concurrency can be enabled by setting flag during
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* table creation.
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*
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* @param h
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* Hash table to look in.
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* @param key
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* Key to find.
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* @param data
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* Output with pointer to data returned from the hash table.
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* @return
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* - A positive value that can be used by the caller as an offset into an
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* array of user data. This value is unique for this key, and is the same
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* value that was returned when the key was added.
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* - -EINVAL if the parameters are invalid.
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* - -ENOENT if the key is not found.
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*/
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int
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rte_hash_lookup_data(const struct rte_hash *h, const void *key, void **data);
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/**
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* Find a key-value pair with a pre-computed hash value
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* to an existing hash table.
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* This operation is multi-thread safe with regarding to other lookup threads.
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* Read-write concurrency can be enabled by setting flag during
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* table creation.
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*
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* @param h
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* Hash table to look in.
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* @param key
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* Key to find.
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* @param sig
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* Precomputed hash value for 'key'
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* @param data
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* Output with pointer to data returned from the hash table.
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* @return
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* - A positive value that can be used by the caller as an offset into an
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* array of user data. This value is unique for this key, and is the same
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* value that was returned when the key was added.
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* - -EINVAL if the parameters are invalid.
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* - -ENOENT if the key is not found.
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*/
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int
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rte_hash_lookup_with_hash_data(const struct rte_hash *h, const void *key,
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hash_sig_t sig, void **data);
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/**
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* Find a key in the hash table.
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* This operation is multi-thread safe with regarding to other lookup threads.
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* Read-write concurrency can be enabled by setting flag during
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* table creation.
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*
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* @param h
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* Hash table to look in.
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* @param key
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* Key to find.
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* @return
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* - -EINVAL if the parameters are invalid.
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* - -ENOENT if the key is not found.
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* - A positive value that can be used by the caller as an offset into an
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* array of user data. This value is unique for this key, and is the same
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* value that was returned when the key was added.
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*/
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int32_t
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rte_hash_lookup(const struct rte_hash *h, const void *key);
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/**
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* Find a key in the hash table.
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* This operation is multi-thread safe with regarding to other lookup threads.
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* Read-write concurrency can be enabled by setting flag during
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* table creation.
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*
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* @param h
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* Hash table to look in.
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* @param key
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* Key to find.
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* @param sig
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* Precomputed hash value for 'key'.
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* @return
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* - -EINVAL if the parameters are invalid.
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* - -ENOENT if the key is not found.
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* - A positive value that can be used by the caller as an offset into an
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* array of user data. This value is unique for this key, and is the same
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* value that was returned when the key was added.
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*/
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int32_t
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rte_hash_lookup_with_hash(const struct rte_hash *h,
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const void *key, hash_sig_t sig);
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/**
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* Calc a hash value by key.
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* This operation is not multi-thread safe.
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*
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* @param h
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* Hash table to look in.
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* @param key
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* Key to find.
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* @return
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* - hash value
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|
*/
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|
hash_sig_t
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|
rte_hash_hash(const struct rte_hash *h, const void *key);
|
|
|
|
/**
|
|
* Find multiple keys in the hash table.
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|
* This operation is multi-thread safe with regarding to other lookup threads.
|
|
* Read-write concurrency can be enabled by setting flag during
|
|
* table creation.
|
|
*
|
|
* @param h
|
|
* Hash table to look in.
|
|
* @param keys
|
|
* A pointer to a list of keys to look for.
|
|
* @param num_keys
|
|
* How many keys are in the keys list (less than RTE_HASH_LOOKUP_BULK_MAX).
|
|
* @param hit_mask
|
|
* Output containing a bitmask with all successful lookups.
|
|
* @param data
|
|
* Output containing array of data returned from all the successful lookups.
|
|
* @return
|
|
* -EINVAL if there's an error, otherwise number of successful lookups.
|
|
*/
|
|
int
|
|
rte_hash_lookup_bulk_data(const struct rte_hash *h, const void **keys,
|
|
uint32_t num_keys, uint64_t *hit_mask, void *data[]);
|
|
|
|
/**
|
|
* Find multiple keys in the hash table.
|
|
* This operation is multi-thread safe with regarding to other lookup threads.
|
|
* Read-write concurrency can be enabled by setting flag during
|
|
* table creation.
|
|
*
|
|
* @param h
|
|
* Hash table to look in.
|
|
* @param keys
|
|
* A pointer to a list of keys to look for.
|
|
* @param num_keys
|
|
* How many keys are in the keys list (less than RTE_HASH_LOOKUP_BULK_MAX).
|
|
* @param positions
|
|
* Output containing a list of values, corresponding to the list of keys that
|
|
* can be used by the caller as an offset into an array of user data. These
|
|
* values are unique for each key, and are the same values that were returned
|
|
* when each key was added. If a key in the list was not found, then -ENOENT
|
|
* will be the value.
|
|
* @return
|
|
* -EINVAL if there's an error, otherwise 0.
|
|
*/
|
|
int
|
|
rte_hash_lookup_bulk(const struct rte_hash *h, const void **keys,
|
|
uint32_t num_keys, int32_t *positions);
|
|
|
|
/**
|
|
* Iterate through the hash table, returning key-value pairs.
|
|
*
|
|
* @param h
|
|
* Hash table to iterate
|
|
* @param key
|
|
* Output containing the key where current iterator
|
|
* was pointing at
|
|
* @param data
|
|
* Output containing the data associated with key.
|
|
* Returns NULL if data was not stored.
|
|
* @param next
|
|
* Pointer to iterator. Should be 0 to start iterating the hash table.
|
|
* Iterator is incremented after each call of this function.
|
|
* @return
|
|
* Position where key was stored, if successful.
|
|
* - -EINVAL if the parameters are invalid.
|
|
* - -ENOENT if end of the hash table.
|
|
*/
|
|
int32_t
|
|
rte_hash_iterate(const struct rte_hash *h, const void **key, void **data, uint32_t *next);
|
|
#ifdef __cplusplus
|
|
}
|
|
#endif
|
|
|
|
#endif /* _RTE_HASH_H_ */
|