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BUF_RING(9) FreeBSD Kernel Developer's Manual BUF_RING(9)
NAME
buf_ring, buf_ring_alloc, buf_ring_free, buf_ring_enqueue,
buf_ring_dequeue_mc, buf_ring_dequeue_sc, buf_ring_count, buf_ring_empty,
buf_ring_full, buf_ring_peek - multi-producer, {single, multi}-consumer
lock-less ring buffer
SYNOPSIS
#include <sys/param.h>
#include <sys/buf_ring.h>
struct buf_ring *
buf_ring_alloc(int count, struct malloc_type *type, int flags,
struct mtx *sc_lock);
void
buf_ring_free(struct buf_ring *br, struct malloc_type *type);
int
buf_ring_enqueue(struct buf_ring *br, void *buf);
void *
buf_ring_dequeue_mc(struct buf_ring *br);
void *
buf_ring_dequeue_sc(struct buf_ring *br);
int
buf_ring_count(struct buf_ring *br);
int
buf_ring_empty(struct buf_ring *br);
int
buf_ring_full(struct buf_ring *br);
void *
buf_ring_peek(struct buf_ring *br);
DESCRIPTION
The buf_ring functions provide a lock-less multi-producer and lock-less
multi-consumer as well as single-consumer ring buffer.
The buf_ring_alloc() function is used to allocate a buf_ring ring buffer
with count slots using malloc_type type and memory flags flags. The
single consumer interface is protected by sc_lock.
The buf_ring_free() function is used to free a buf_ring. The user is
responsible for freeing any enqueued items.
The buf_ring_enqueue() function is used to enqueue a buffer to a
buf_ring.
The buf_ring_dequeue_mc() function is a multi-consumer safe way of
dequeueing elements from a buf_ring.
The buf_ring_dequeue_sc() function is a single-consumer interface to
dequeue elements - requiring the user to serialize accesses with a lock.
The buf_ring_full() function returns TRUE if no more items can be
enqueued, FALSE otherwise.
The buf_ring_peek() function returns a pointer to the last element in the
buf_ring if the buf_ring is not empty, NULL otherwise.
RETURN VALUES
The buf_ring_enqueue() function return ENOBUFS if there are no available
slots in the buf_ring.
HISTORY
These functions were introduced in FreeBSD 8.0.
FreeBSD 14.0-RELEASE-p11 September 27, 2012 FreeBSD 14.0-RELEASE-p11