/* *------------------------------------------------------------------ * 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_send_signal (svm_queue_t * q, u8 is_prod); 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: */