table of contents
| BUF_RING(9) | 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, —
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¶
Thebuf_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_count() function returns the
number of elements in a buf_ring.
The buf_ring_empty() function returns
TRUE if the buf_ring is empty,
FALSE otherwise.
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¶
Thebuf_ring_enqueue() function return
ENOBUFS if there are no available slots in the
buf_ring.
HISTORY¶
These functions were introduced in FreeBSD 8.0.| September 27, 2012 | Linux 4.9.0-9-amd64 |