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Diffstat (limited to 'src/dpdk_lib18/librte_hash/rte_fbk_hash.h')
| -rwxr-xr-x | src/dpdk_lib18/librte_hash/rte_fbk_hash.h | 397 |
1 files changed, 397 insertions, 0 deletions
diff --git a/src/dpdk_lib18/librte_hash/rte_fbk_hash.h b/src/dpdk_lib18/librte_hash/rte_fbk_hash.h new file mode 100755 index 00000000..3d229bf9 --- /dev/null +++ b/src/dpdk_lib18/librte_hash/rte_fbk_hash.h @@ -0,0 +1,397 @@ +/*- + * BSD LICENSE + * + * Copyright(c) 2010-2014 Intel Corporation. All rights reserved. + * All rights reserved. + * + * Redistribution and use in source and binary forms, with or without + * modification, are permitted provided that the following conditions + * are met: + * + * * Redistributions of source code must retain the above copyright + * notice, this list of conditions and the following disclaimer. + * * Redistributions in binary form must reproduce the above copyright + * notice, this list of conditions and the following disclaimer in + * the documentation and/or other materials provided with the + * distribution. + * * Neither the name of Intel Corporation nor the names of its + * contributors may be used to endorse or promote products derived + * from this software without specific prior written permission. + * + * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + */ + +#ifndef _RTE_FBK_HASH_H_ +#define _RTE_FBK_HASH_H_ + +/** + * @file + * + * This is a hash table implementation for four byte keys (fbk). + * + * Note that the return value of the add function should always be checked as, + * if a bucket is full, the key is not added even if there is space in other + * buckets. This keeps the lookup function very simple and therefore fast. + */ + +#include <stdint.h> +#include <errno.h> +#include <sys/queue.h> + +#ifdef __cplusplus +extern "C" { +#endif + +#include <string.h> + +#ifndef RTE_FBK_HASH_FUNC_DEFAULT +#ifdef RTE_MACHINE_CPUFLAG_SSE4_2 +#include <rte_hash_crc.h> +/** Default four-byte key hash function if none is specified. */ +#define RTE_FBK_HASH_FUNC_DEFAULT rte_hash_crc_4byte +#else +#include <rte_jhash.h> +#define RTE_FBK_HASH_FUNC_DEFAULT rte_jhash_1word +#endif +#endif + +#ifndef RTE_FBK_HASH_INIT_VAL_DEFAULT +/** Initialising value used when calculating hash. */ +#define RTE_FBK_HASH_INIT_VAL_DEFAULT 0xFFFFFFFF +#endif + +/** The maximum number of entries in the hash table that is supported. */ +#define RTE_FBK_HASH_ENTRIES_MAX (1 << 20) + +/** The maximum number of entries in each bucket that is supported. */ +#define RTE_FBK_HASH_ENTRIES_PER_BUCKET_MAX 256 + +/** Maximum size of string for naming the hash. */ +#define RTE_FBK_HASH_NAMESIZE 32 + +/** Type of function that can be used for calculating the hash value. */ +typedef uint32_t (*rte_fbk_hash_fn)(uint32_t key, uint32_t init_val); + +/** Parameters used when creating four-byte key hash table. */ +struct rte_fbk_hash_params { + const char *name; /**< Name of the hash table. */ + uint32_t entries; /**< Total number of entries. */ + uint32_t entries_per_bucket; /**< Number of entries in a bucket. */ + int socket_id; /**< Socket to allocate memory on. */ + rte_fbk_hash_fn hash_func; /**< The hash function. */ + uint32_t init_val; /**< For initialising hash function. */ +}; + +/** Individual entry in the four-byte key hash table. */ +union rte_fbk_hash_entry { + uint64_t whole_entry; /**< For accessing entire entry. */ + struct { + uint16_t is_entry; /**< Non-zero if entry is active. */ + uint16_t value; /**< Value returned by lookup. */ + uint32_t key; /**< Key used to find value. */ + } entry; /**< For accessing each entry part. */ +}; + + +/** The four-byte key hash table structure. */ +struct rte_fbk_hash_table { + char name[RTE_FBK_HASH_NAMESIZE]; /**< Name of the hash. */ + uint32_t entries; /**< Total number of entries. */ + uint32_t entries_per_bucket; /**< Number of entries in a bucket. */ + uint32_t used_entries; /**< How many entries are used. */ + uint32_t bucket_mask; /**< To find which bucket the key is in. */ + uint32_t bucket_shift; /**< Convert bucket to table offset. */ + rte_fbk_hash_fn hash_func; /**< The hash function. */ + uint32_t init_val; /**< For initialising hash function. */ + + /** A flat table of all buckets. */ + union rte_fbk_hash_entry t[0]; +}; + +/** + * Find the offset into hash table of the bucket containing a particular key. + * + * @param ht + * Pointer to hash table. + * @param key + * Key to calculate bucket for. + * @return + * Offset into hash table. + */ +static inline uint32_t +rte_fbk_hash_get_bucket(const struct rte_fbk_hash_table *ht, uint32_t key) +{ + return (ht->hash_func(key, ht->init_val) & ht->bucket_mask) << + ht->bucket_shift; +} + +/** + * Add a key to an existing hash table with bucket id. + * This operation is not multi-thread safe + * and should only be called from one thread. + * + * @param ht + * Hash table to add the key to. + * @param key + * Key to add to the hash table. + * @param value + * Value to associate with key. + * @param bucket + * Bucket to associate with key. + * @return + * 0 if ok, or negative value on error. + */ +static inline int +rte_fbk_hash_add_key_with_bucket(struct rte_fbk_hash_table *ht, + uint32_t key, uint16_t value, uint32_t bucket) +{ + /* + * The writing of a new value to the hash table is done as a single + * 64bit operation. This should help prevent individual entries being + * corrupted due to race conditions, but it's still possible to + * overwrite entries that have just been made valid. + */ + const uint64_t new_entry = ((uint64_t)(key) << 32) | + ((uint64_t)(value) << 16) | + 1; /* 1 = is_entry bit. */ + uint32_t i; + + for (i = 0; i < ht->entries_per_bucket; i++) { + /* Set entry if unused. */ + if (! ht->t[bucket + i].entry.is_entry) { + ht->t[bucket + i].whole_entry = new_entry; + ht->used_entries++; + return 0; + } + /* Change value if key already exists. */ + if (ht->t[bucket + i].entry.key == key) { + ht->t[bucket + i].entry.value = value; + return 0; + } + } + + return -ENOSPC; /* No space in bucket. */ +} + +/** + * Add a key to an existing hash table. This operation is not multi-thread safe + * and should only be called from one thread. + * + * @param ht + * Hash table to add the key to. + * @param key + * Key to add to the hash table. + * @param value + * Value to associate with key. + * @return + * 0 if ok, or negative value on error. + */ +static inline int +rte_fbk_hash_add_key(struct rte_fbk_hash_table *ht, + uint32_t key, uint16_t value) +{ + return rte_fbk_hash_add_key_with_bucket(ht, + key, value, rte_fbk_hash_get_bucket(ht, key)); +} + +/** + * Remove a key with a given bucket id from an existing hash table. + * This operation is not multi-thread + * safe and should only be called from one thread. + * + * @param ht + * Hash table to remove the key from. + * @param key + * Key to remove from the hash table. + * @param bucket + * Bucket id associate with key. + * @return + * 0 if ok, or negative value on error. + */ +static inline int +rte_fbk_hash_delete_key_with_bucket(struct rte_fbk_hash_table *ht, + uint32_t key, uint32_t bucket) +{ + uint32_t last_entry = ht->entries_per_bucket - 1; + uint32_t i, j; + + for (i = 0; i < ht->entries_per_bucket; i++) { + if (ht->t[bucket + i].entry.key == key) { + /* Find last key in bucket. */ + for (j = ht->entries_per_bucket - 1; j > i; j-- ) { + if (! ht->t[bucket + j].entry.is_entry) { + last_entry = j - 1; + } + } + /* + * Move the last key to the deleted key's position, and + * delete the last key. lastEntry and i may be same but + * it doesn't matter. + */ + ht->t[bucket + i].whole_entry = + ht->t[bucket + last_entry].whole_entry; + ht->t[bucket + last_entry].whole_entry = 0; + + ht->used_entries--; + return 0; + } + } + + return -ENOENT; /* Key didn't exist. */ +} + +/** + * Remove a key from an existing hash table. This operation is not multi-thread + * safe and should only be called from one thread. + * + * @param ht + * Hash table to remove the key from. + * @param key + * Key to remove from the hash table. + * @return + * 0 if ok, or negative value on error. + */ +static inline int +rte_fbk_hash_delete_key(struct rte_fbk_hash_table *ht, uint32_t key) +{ + return rte_fbk_hash_delete_key_with_bucket(ht, + key, rte_fbk_hash_get_bucket(ht, key)); +} + +/** + * Find a key in the hash table with a given bucketid. + * This operation is multi-thread safe. + * + * @param ht + * Hash table to look in. + * @param key + * Key to find. + * @param bucket + * Bucket associate to the key. + * @return + * The value that was associated with the key, or negative value on error. + */ +static inline int +rte_fbk_hash_lookup_with_bucket(const struct rte_fbk_hash_table *ht, + uint32_t key, uint32_t bucket) +{ + union rte_fbk_hash_entry current_entry; + uint32_t i; + + for (i = 0; i < ht->entries_per_bucket; i++) { + /* Single read of entry, which should be atomic. */ + current_entry.whole_entry = ht->t[bucket + i].whole_entry; + if (! current_entry.entry.is_entry) { + return -ENOENT; /* Error once we hit an empty field. */ + } + if (current_entry.entry.key == key) { + return current_entry.entry.value; + } + } + return -ENOENT; /* Key didn't exist. */ +} + +/** + * Find a key in the hash table. This operation is multi-thread safe. + * + * @param ht + * Hash table to look in. + * @param key + * Key to find. + * @return + * The value that was associated with the key, or negative value on error. + */ +static inline int +rte_fbk_hash_lookup(const struct rte_fbk_hash_table *ht, uint32_t key) +{ + return rte_fbk_hash_lookup_with_bucket(ht, + key, rte_fbk_hash_get_bucket(ht, key)); +} + +/** + * Delete all entries in a hash table. This operation is not multi-thread + * safe and should only be called from one thread. + * + * @param ht + * Hash table to delete entries in. + */ +static inline void +rte_fbk_hash_clear_all(struct rte_fbk_hash_table *ht) +{ + memset(ht->t, 0, sizeof(ht->t[0]) * ht->entries); + ht->used_entries = 0; +} + +/** + * Find what fraction of entries are being used. + * + * @param ht + * Hash table to find how many entries are being used in. + * @return + * Load factor of the hash table, or negative value on error. + */ +static inline double +rte_fbk_hash_get_load_factor(struct rte_fbk_hash_table *ht) +{ + return (double)ht->used_entries / (double)ht->entries; +} + +/** + * Performs a lookup for an existing hash table, and returns a pointer to + * the table if found. + * + * @param name + * Name of the hash table to find + * + * @return + * pointer to hash table structure or NULL on error with rte_errno + * set appropriately. Possible rte_errno values include: + * - ENOENT - required entry not available to return. + */ +struct rte_fbk_hash_table *rte_fbk_hash_find_existing(const char *name); + +/** + * Create a new hash table for use with four byte keys. + * + * @param params + * Parameters used in creation of hash table. + * + * @return + * Pointer to hash table structure that is used in future hash table + * operations, or NULL on error with rte_errno set appropriately. + * Possible rte_errno error values include: + * - E_RTE_NO_CONFIG - function could not get pointer to rte_config structure + * - E_RTE_SECONDARY - function was called from a secondary process instance + * - E_RTE_NO_TAILQ - no tailq list could be got for the fbk hash table list + * - EINVAL - invalid parameter value passed to function + * - ENOSPC - the maximum number of memzones has already been allocated + * - EEXIST - a memzone with the same name already exists + * - ENOMEM - no appropriate memory area found in which to create memzone + */ +struct rte_fbk_hash_table * \ +rte_fbk_hash_create(const struct rte_fbk_hash_params *params); + +/** + * Free all memory used by a hash table. + * Has no effect on hash tables allocated in memory zones + * + * @param ht + * Hash table to deallocate. + */ +void rte_fbk_hash_free(struct rte_fbk_hash_table *ht); + +#ifdef __cplusplus +} +#endif + +#endif /* _RTE_FBK_HASH_H_ */ |