Provided by: dpdk-doc_24.11.2-2_all 
NAME
rte_hash.h
SYNOPSIS
#include <stdint.h>
#include <stddef.h>
#include <rte_rcu_qsbr.h>
Data Structures
struct rte_hash_parameters
struct rte_hash_rcu_config
Macros
#define RTE_HASH_ENTRIES_MAX (1 << 30)
#define RTE_HASH_NAMESIZE 32
#define RTE_HASH_LOOKUP_BULK_MAX 64
#define RTE_HASH_EXTRA_FLAGS_TRANS_MEM_SUPPORT 0x01
#define RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD 0x02
#define RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY 0x04
#define RTE_HASH_EXTRA_FLAGS_EXT_TABLE 0x08
#define RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL 0x10
#define RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF 0x20
Typedefs
typedef uint32_t hash_sig_t
typedef uint32_t(* rte_hash_function) (const void *key, uint32_t key_len, uint32_t init_val)
typedef int(* rte_hash_cmp_eq_t) (const void *key1, const void *key2, size_t key_len)
typedef void(* rte_hash_free_key_data) (void *p, void *key_data)
Enumerations
enum rte_hash_qsbr_mode { RTE_HASH_QSBR_MODE_DQ = 0, RTE_HASH_QSBR_MODE_SYNC }
Functions
struct rte_hash * rte_hash_create (const struct rte_hash_parameters *params)
void rte_hash_set_cmp_func (struct rte_hash *h, rte_hash_cmp_eq_t func)
struct rte_hash * rte_hash_find_existing (const char *name)
void rte_hash_free (struct rte_hash *h)
void rte_hash_reset (struct rte_hash *h)
int32_t rte_hash_count (const struct rte_hash *h)
int32_t rte_hash_max_key_id (const struct rte_hash *h)
int rte_hash_add_key_data (const struct rte_hash *h, const void *key, void *data)
int32_t rte_hash_add_key_with_hash_data (const struct rte_hash *h, const void *key, hash_sig_t sig, void
*data)
int32_t rte_hash_add_key (const struct rte_hash *h, const void *key)
int32_t rte_hash_add_key_with_hash (const struct rte_hash *h, const void *key, hash_sig_t sig)
int32_t rte_hash_del_key (const struct rte_hash *h, const void *key)
int32_t rte_hash_del_key_with_hash (const struct rte_hash *h, const void *key, hash_sig_t sig)
int rte_hash_get_key_with_position (const struct rte_hash *h, const int32_t position, void **key)
int rte_hash_free_key_with_position (const struct rte_hash *h, const int32_t position)
int rte_hash_lookup_data (const struct rte_hash *h, const void *key, void **data)
int rte_hash_lookup_with_hash_data (const struct rte_hash *h, const void *key, hash_sig_t sig, void
**data)
int32_t rte_hash_lookup (const struct rte_hash *h, const void *key)
int32_t rte_hash_lookup_with_hash (const struct rte_hash *h, const void *key, hash_sig_t sig)
hash_sig_t rte_hash_hash (const struct rte_hash *h, const void *key)
int rte_hash_lookup_bulk_data (const struct rte_hash *h, const void **keys, uint32_t num_keys, uint64_t
*hit_mask, void *data[])
int rte_hash_lookup_with_hash_bulk (const struct rte_hash *h, const void **keys, hash_sig_t *sig,
uint32_t num_keys, int32_t *positions)
int rte_hash_lookup_with_hash_bulk_data (const struct rte_hash *h, const void **keys, hash_sig_t *sig,
uint32_t num_keys, uint64_t *hit_mask, void *data[])
int rte_hash_lookup_bulk (const struct rte_hash *h, const void **keys, uint32_t num_keys, int32_t
*positions)
int32_t rte_hash_iterate (const struct rte_hash *h, const void **key, void **data, uint32_t *next)
int rte_hash_rcu_qsbr_add (struct rte_hash *h, struct rte_hash_rcu_config *cfg)
__rte_experimental int rte_hash_rcu_qsbr_dq_reclaim (struct rte_hash *h, unsigned int *freed, unsigned
int *pending, unsigned int *available)
Detailed Description
RTE Hash Table
Definition in file rte_hash.h.
Macro Definition Documentation
#define RTE_HASH_ENTRIES_MAX (1 << 30)
Maximum size of hash table that can be created.
Definition at line 24 of file rte_hash.h.
#define RTE_HASH_NAMESIZE 32
Maximum number of characters in hash name.
Definition at line 27 of file rte_hash.h.
#define RTE_HASH_LOOKUP_BULK_MAX 64
Maximum number of keys that can be searched for using rte_hash_lookup_bulk.
Definition at line 30 of file rte_hash.h.
#define RTE_HASH_EXTRA_FLAGS_TRANS_MEM_SUPPORT 0x01
Enable Hardware transactional memory support.
Definition at line 34 of file rte_hash.h.
#define RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD 0x02
Default behavior of insertion, single writer/multi writer
Definition at line 37 of file rte_hash.h.
#define RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY 0x04
Flag to support reader writer concurrency
Definition at line 40 of file rte_hash.h.
#define RTE_HASH_EXTRA_FLAGS_EXT_TABLE 0x08
Flag to indicate the extendable bucket table feature should be used
Definition at line 43 of file rte_hash.h.
#define RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL 0x10
Flag to disable freeing of key index on hash delete. Refer to rte_hash_del_xxx APIs for more details.
This is enabled by default when RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF is enabled. However, if internal
RCU is enabled, freeing of internal memory/index is done on delete
Definition at line 51 of file rte_hash.h.
#define RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF 0x20
Flag to support lock free reader writer concurrency. Both single writer and multi writer use cases are
supported.
Definition at line 56 of file rte_hash.h.
Typedef Documentation
typedef uint32_t hash_sig_t
The type of hash value of a key. It should be a value of at least 32bit with fully random pattern.
Definition at line 62 of file rte_hash.h.
typedef uint32_t(* rte_hash_function) (const void *key, uint32_t key_len, uint32_t init_val)
Type of function that can be used for calculating the hash value.
Definition at line 65 of file rte_hash.h.
typedef int(* rte_hash_cmp_eq_t) (const void *key1, const void *key2, size_t key_len)
Type of function used to compare the hash key.
Definition at line 69 of file rte_hash.h.
typedef void(* rte_hash_free_key_data) (void *p, void *key_data)
Type of function used to free data stored in the key. Required when using internal RCU to allow
application to free key-data once the key is returned to the ring of free key-slots.
Definition at line 76 of file rte_hash.h.
Enumeration Type Documentation
enum rte_hash_qsbr_mode
RCU reclamation modes
Enumerator
RTE_HASH_QSBR_MODE_DQ
Create defer queue for reclaim.
RTE_HASH_QSBR_MODE_SYNC
Use blocking mode reclaim. No defer queue created.
Definition at line 93 of file rte_hash.h.
Function Documentation
struct rte_hash * rte_hash_create (const struct rte_hash_parameters * params)
Create a new hash table.
Parameters
params Parameters used to create and initialise the hash table.
Returns
Pointer to hash table structure that is used in future hash table operations, or NULL on error, with
error code set in rte_errno. Possible rte_errno errors 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
• ENOENT - missing entry
• EINVAL - invalid parameter 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
void rte_hash_set_cmp_func (struct rte_hash * h, rte_hash_cmp_eq_t func)
Set a new hash compare function other than the default one.
Note
Function pointer does not work with multi-process, so do not use it in multi-process mode.
Parameters
h Hash table for which the function is to be changed
func New compare function
struct rte_hash * rte_hash_find_existing (const char * name)
Find an existing hash table object and return a pointer to it.
Parameters
name Name of the hash table as passed to rte_hash_create()
Returns
Pointer to hash table or NULL if object not found with rte_errno set appropriately. Possible
rte_errno values include:
• ENOENT - value not available for return
void rte_hash_free (struct rte_hash * h)
De-allocate all memory used by hash table.
Parameters
h Hash table to free, if NULL, the function does nothing.
void rte_hash_reset (struct rte_hash * h)
Reset all hash structure, by zeroing all entries. When RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF is enabled,
it is application's responsibility to make sure that none of the readers are referencing the hash table
while calling this API.
Parameters
h Hash table to reset
int32_t rte_hash_count (const struct rte_hash * h)
Return the number of keys in the hash table
Parameters
h Hash table to query from
Returns
• -EINVAL if parameters are invalid
• A value indicating how many keys were inserted in the table.
int32_t rte_hash_max_key_id (const struct rte_hash * h)
Return the maximum key value ID that could possibly be returned by rte_hash_add_key function.
Parameters
h Hash table to query from
Returns
• -EINVAL if parameters are invalid
• A value indicating the max key ID of key slots present in the table.
int rte_hash_add_key_data (const struct rte_hash * h, const void * key, void * data)
Add a key-value pair to an existing hash table. This operation is not multi-thread safe and should only
be called from one thread by default. Thread safety can be enabled by setting flag during table creation.
If the key exists already in the table, this API updates its value with 'data' passed in this API. It is
the responsibility of the application to manage any memory associated with the old value. The readers
might still be using the old value even after this API has returned.
Parameters
h Hash table to add the key to.
key Key to add to the hash table.
data Data to add to the hash table.
Returns
• 0 if added successfully
• -EINVAL if the parameters are invalid.
• -ENOSPC if there is no space in the hash for this key.
int32_t rte_hash_add_key_with_hash_data (const struct rte_hash * h, const void * key, hash_sig_t sig, void *
data)
Add a key-value pair with a pre-computed hash value to an existing hash table. This operation is not
multi-thread safe and should only be called from one thread by default. Thread safety can be enabled by
setting flag during table creation. If the key exists already in the table, this API updates its value
with 'data' passed in this API. It is the responsibility of the application to manage any memory
associated with the old value. The readers might still be using the old value even after this API has
returned.
Parameters
h Hash table to add the key to.
key Key to add to the hash table.
sig Precomputed hash value for 'key'
data Data to add to the hash table.
Returns
• 0 if added successfully
• -EINVAL if the parameters are invalid.
• -ENOSPC if there is no space in the hash for this key.
int32_t rte_hash_add_key (const struct rte_hash * h, const void * key)
Add a key to an existing hash table. This operation is not multi-thread safe and should only be called
from one thread by default. Thread safety can be enabled by setting flag during table creation.
Parameters
h Hash table to add the key to.
key Key to add to the hash table.
Returns
• -EINVAL if the parameters are invalid.
• -ENOSPC if there is no space in the hash for this key.
• A non-negative value that can be used by the caller as an offset into an array of user data. This
value is unique for this key. This unique key id may be larger than the user specified entry count
when RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD flag is set.
int32_t rte_hash_add_key_with_hash (const struct rte_hash * h, const void * key, hash_sig_t sig)
Add a key to an existing hash table. This operation is not multi-thread safe and should only be called
from one thread by default. Thread safety can be enabled by setting flag during table creation.
Parameters
h Hash table to add the key to.
key Key to add to the hash table.
sig Precomputed hash value for 'key'.
Returns
• -EINVAL if the parameters are invalid.
• -ENOSPC if there is no space in the hash for this key.
• A non-negative value that can be used by the caller as an offset into an array of user data. This
value is unique for this key. This unique key ID may be larger than the user specified entry count
when RTE_HASH_EXTRA_FLAGS_MULTI_WRITER_ADD flag is set.
int32_t rte_hash_del_key (const struct rte_hash * h, const void * key)
Remove a key from an existing hash table. This operation is not multi-thread safe and should only be
called from one thread by default. Thread safety can be enabled by setting flag during table creation. If
RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL or RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF is enabled and internal RCU
is NOT enabled, the key index returned by rte_hash_add_key_xxx APIs will not be freed by this API.
rte_hash_free_key_with_position API must be called additionally to free the index associated with the
key. rte_hash_free_key_with_position API should be called after all the readers have stopped referencing
the entry corresponding to this key. RCU mechanisms could be used to determine such a state.
Parameters
h Hash table to remove the key from.
key Key to remove from the hash table.
Returns
• -EINVAL if the parameters are invalid.
• -ENOENT if the key is not found.
• A non-negative value that can be used by the caller as an offset into an array of user data. This
value is unique for this key, and is the same value that was returned when the key was added.
int32_t rte_hash_del_key_with_hash (const struct rte_hash * h, const void * key, hash_sig_t sig)
Remove a key from an existing hash table. This operation is not multi-thread safe and should only be
called from one thread by default. Thread safety can be enabled by setting flag during table creation. If
RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL or RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF is enabled and internal RCU
is NOT enabled, the key index returned by rte_hash_add_key_xxx APIs will not be freed by this API.
rte_hash_free_key_with_position API must be called additionally to free the index associated with the
key. rte_hash_free_key_with_position API should be called after all the readers have stopped referencing
the entry corresponding to this key. RCU mechanisms could be used to determine such a state.
Parameters
h Hash table to remove the key from.
key Key to remove from the hash table.
sig Precomputed hash value for 'key'.
Returns
• -EINVAL if the parameters are invalid.
• -ENOENT if the key is not found.
• A non-negative value that can be used by the caller as an offset into an array of user data. This
value is unique for this key, and is the same value that was returned when the key was added.
int rte_hash_get_key_with_position (const struct rte_hash * h, const int32_t position, void ** key)
Find a key in the hash table given the position. This operation is multi-thread safe with regarding to
other lookup threads. Read-write concurrency can be enabled by setting flag during table creation.
Parameters
h Hash table to get the key from.
position Position returned when the key was inserted.
key Output containing a pointer to the key
Returns
• 0 if retrieved successfully
• -EINVAL if the parameters are invalid.
• -ENOENT if no valid key is found in the given position.
int rte_hash_free_key_with_position (const struct rte_hash * h, const int32_t position)
Free a hash key in the hash table given the position of the key. This operation is not multi-thread safe
and should only be called from one thread by default. Thread safety can be enabled by setting flag during
table creation. If RTE_HASH_EXTRA_FLAGS_NO_FREE_ON_DEL or RTE_HASH_EXTRA_FLAGS_RW_CONCURRENCY_LF is
enabled and internal RCU is NOT enabled, the key index returned by rte_hash_del_key_xxx APIs must be
freed using this API. This API should be called after all the readers have stopped referencing the entry
corresponding to this key. RCU mechanisms could be used to determine such a state. This API does not
validate if the key is already freed.
Parameters
h Hash table to free the key from.
position Position returned when the key was deleted.
Returns
• 0 if freed successfully
• -EINVAL if the parameters are invalid.
int rte_hash_lookup_data (const struct rte_hash * h, const void * key, void ** data)
Find a key-value pair 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.
Parameters
h Hash table to look in.
key Key to find.
data Output with pointer to data returned from the hash table.
Returns
• A non-negative value that can be used by the caller as an offset into an array of user data. This
value is unique for this key, and is the same value that was returned when the key was added.
• -EINVAL if the parameters are invalid.
• -ENOENT if the key is not found.
int rte_hash_lookup_with_hash_data (const struct rte_hash * h, const void * key, hash_sig_t sig, void **
data)
Find a key-value pair with a pre-computed hash value to an existing 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.
Parameters
h Hash table to look in.
key Key to find.
sig Precomputed hash value for 'key'
data Output with pointer to data returned from the hash table.
Returns
• A non-negative value that can be used by the caller as an offset into an array of user data. This
value is unique for this key, and is the same value that was returned when the key was added.
• -EINVAL if the parameters are invalid.
• -ENOENT if the key is not found.
int32_t rte_hash_lookup (const struct rte_hash * h, const void * key)
Find a key 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.
Parameters
h Hash table to look in.
key Key to find.
Returns
• -EINVAL if the parameters are invalid.
• -ENOENT if the key is not found.
• A non-negative value that can be used by the caller as an offset into an array of user data. This
value is unique for this key, and is the same value that was returned when the key was added.
int32_t rte_hash_lookup_with_hash (const struct rte_hash * h, const void * key, hash_sig_t sig)
Find a key 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.
Parameters
h Hash table to look in.
key Key to find.
sig Precomputed hash value for 'key'.
Returns
• -EINVAL if the parameters are invalid.
• -ENOENT if the key is not found.
• A non-negative value that can be used by the caller as an offset into an array of user data. This
value is unique for this key, and is the same value that was returned when the key was added.
hash_sig_t rte_hash_hash (const struct rte_hash * h, const void * key)
Calc a hash value by key. This operation is not multi-process safe.
Parameters
h Hash table to look in.
key Key to find.
Returns
• hash value
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.
Parameters
h Hash table to look in.
keys A pointer to a list of keys to look for.
num_keys How many keys are in the keys list (less than RTE_HASH_LOOKUP_BULK_MAX).
hit_mask Output containing a bitmask with all successful lookups.
data Output containing array of data returned from all the successful lookups.
Returns
-EINVAL if there's an error, otherwise number of successful lookups.
int rte_hash_lookup_with_hash_bulk (const struct rte_hash * h, const void ** keys, hash_sig_t * sig, uint32_t
num_keys, int32_t * positions)
Find multiple keys in the hash table with precomputed hash value array. This operation is multi-thread
safe with regarding to other lookup threads. Read-write concurrency can be enabled by setting flag during
table creation.
Parameters
h Hash table to look in.
keys A pointer to a list of keys to look for.
sig A pointer to a list of precomputed hash values for keys.
num_keys How many keys are in the keys list (less than RTE_HASH_LOOKUP_BULK_MAX).
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.
Returns
-EINVAL if there's an error, otherwise 0.
int rte_hash_lookup_with_hash_bulk_data (const struct rte_hash * h, const void ** keys, hash_sig_t * sig,
uint32_t num_keys, uint64_t * hit_mask, void * data[])
Find multiple keys in the hash table with precomputed hash value array. This operation is multi-thread
safe with regarding to other lookup threads. Read-write concurrency can be enabled by setting flag during
table creation.
Parameters
h Hash table to look in.
keys A pointer to a list of keys to look for.
sig A pointer to a list of precomputed hash values for keys.
num_keys How many keys are in the keys list (less than RTE_HASH_LOOKUP_BULK_MAX).
hit_mask Output containing a bitmask with all successful lookups.
data Output containing array of data returned from all the successful lookups.
Returns
-EINVAL if there's an error, otherwise number of successful lookups.
int rte_hash_lookup_bulk (const struct rte_hash * h, const void ** keys, uint32_t num_keys, int32_t *
positions)
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.
Parameters
h Hash table to look in.
keys A pointer to a list of keys to look for.
num_keys How many keys are in the keys list (less than RTE_HASH_LOOKUP_BULK_MAX).
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.
Returns
-EINVAL if there's an error, otherwise 0.
int32_t rte_hash_iterate (const struct rte_hash * h, const void ** key, void ** data, uint32_t * next)
Iterate through the hash table, returning key-value pairs.
Parameters
h Hash table to iterate
key Output containing the key where current iterator was pointing at
data Output containing the data associated with key. Returns NULL if data was not stored.
next Pointer to iterator. Should be 0 to start iterating the hash table. Iterator is incremented
after each call of this function.
Returns
Position where key was stored, if successful.
• -EINVAL if the parameters are invalid.
• -ENOENT if end of the hash table.
int rte_hash_rcu_qsbr_add (struct rte_hash * h, struct rte_hash_rcu_config * cfg)
Associate RCU QSBR variable with a Hash object. This API should be called to enable the integrated RCU
QSBR support and should be called immediately after creating the Hash object.
Parameters
h the hash object to add RCU QSBR
cfg RCU QSBR configuration
Returns
On success - 0 On error - 1 with error code set in rte_errno. Possible rte_errno codes are:
• EINVAL - invalid pointer
• EEXIST - already added QSBR
• ENOMEM - memory allocation failure
__rte_experimental int rte_hash_rcu_qsbr_dq_reclaim (struct rte_hash * h, unsigned int * freed, unsigned int
* pending, unsigned int * available)
Reclaim resources from the defer queue. This API reclaim the resources from the defer queue if rcu is
enabled.
Parameters
h The hash object to reclaim resources.
freed Number of resources that were freed.
pending Number of resources pending on the defer queue. This number might not be accurate if multi-
thread safety is configured.
available Number of resources that can be added to the defer queue. This number might not be accurate
if multi-thread safety is configured.
Returns
On success - 0 On error - 1 with error code set in rte_errno. Possible rte_errno codes are:
• EINVAL - invalid pointer
Author
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DPDK Version 24.11.2 rte_hash.h(3)