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/*
*------------------------------------------------------------------
* svm_queue.h - shared-memory queues
*
* Copyright (c) 2009-2019 Cisco and/or its affiliates.
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at:
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*------------------------------------------------------------------
*/
#ifndef included_svm_queue_h
#define included_svm_queue_h
#include <pthread.h>
typedef struct _svm_queue
{
pthread_mutex_t mutex; /* 8 bytes */
pthread_cond_t condvar; /* 8 bytes */
int head;
int tail;
volatile int cursize;
int maxsize;
int elsize;
int consumer_pid;
int producer_evtfd;
int consumer_evtfd;
char data[0];
} svm_queue_t;
typedef enum
{
SVM_Q_WAIT = 0, /**< blocking call - best used in combination with
condvars, for eventfds we don't yield the cpu */
SVM_Q_NOWAIT, /**< non-blocking call - works with both condvar and
eventfd signaling */
SVM_Q_TIMEDWAIT, /**< blocking call, returns on signal or time-out -
best used in combination with condvars, with
eventfds we don't yield the cpu */
} svm_q_conditional_wait_t;
/**
* Allocate and initialize svm queue
*
* @param nels number of elements on the queue
* @param elsize element size, presumably 4 and cacheline-size will
* be popular choices.
* @param pid consumer pid
* @return a newly initialized svm queue
*
* The idea is to call this function in the queue consumer,
* and e-mail the queue pointer to the producer(s).
*
* The vpp process / main thread allocates one of these
* at startup; its main input queue. The vpp main input queue
* has a pointer to it in the shared memory segment header.
*
* You probably want to be on an svm data heap before calling this
* function.
*/
svm_queue_t *svm_queue_alloc_and_init (int nels, int elsize,
int consumer_pid);
svm_queue_t *svm_queue_init (void *base, int nels, int elsize);
void svm_queue_free (svm_queue_t * q);
int svm_queue_add (svm_queue_t * q, u8 * elem, int nowait);
int svm_queue_add2 (svm_queue_t * q, u8 * elem, u8 * elem2, int nowait);
int svm_queue_sub (svm_queue_t * q, u8 * elem, svm_q_conditional_wait_t cond,
u32 time);
int svm_queue_sub2 (svm_queue_t * q, u8 * elem);
void svm_queue_lock (svm_queue_t * q);
void svm_queue_unlock (svm_queue_t * q);
int svm_queue_is_full (svm_queue_t * q);
int svm_queue_add_nolock (svm_queue_t * q, u8 * elem);
int svm_queue_sub_raw (svm_queue_t * q, u8 * elem);
/**
* Wait for queue event
*
* Must be called with mutex held.
*/
void svm_queue_wait (svm_queue_t * q);
/**
* Timed wait for queue event
*
* Must be called with mutex held.
*
* @param q svm queue
* @param timeout time in seconds
* @return 0 on success, ETIMEDOUT on timeout or an error
*/
int svm_queue_timedwait (svm_queue_t * q, double timeout);
/**
* Add element to queue with mutex held
* @param q queue
* @param elem pointer element data to add
*/
void svm_queue_add_raw (svm_queue_t * q, u8 * elem);
/**
* Set producer's event fd
*
* When the producer must generate an event it writes 1 to the provided fd.
* Once this is set, condvars are not used anymore for signaling.
*/
void svm_queue_set_producer_event_fd (svm_queue_t * q, int fd);
/**
* Set consumer's event fd
*
* When the consumer must generate an event it writes 1 to the provided fd.
* Although in practice the two fds point to the same underlying file
* description, because the producer and consumer are different processes
* the descriptors will be different. It's the caller's responsibility to
* ensure the file descriptors are properly exchanged between the two peers.
*/
void svm_queue_set_consumer_event_fd (svm_queue_t * q, int fd);
/*
* DEPRECATED please use svm_queue_t instead
*/
typedef svm_queue_t unix_shared_memory_queue_t;
#endif /* included_svm_queue_h */
/*
* fd.io coding-style-patch-verification: ON
*
* Local Variables:
* eval: (c-set-style "gnu")
* End:
*/
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