@@ -1293,6 +1293,7 @@ LIBBPF_API int ring_buffer__add(struct ring_buffer *rb, int map_fd,
ring_buffer_sample_fn sample_cb, void *ctx);
LIBBPF_API int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms);
LIBBPF_API int ring_buffer__consume(struct ring_buffer *rb);
+LIBBPF_API int ring_buffer__consume_n(struct ring_buffer *rb, size_t n);
LIBBPF_API int ring_buffer__epoll_fd(const struct ring_buffer *rb);
/**
@@ -1367,6 +1368,17 @@ LIBBPF_API int ring__map_fd(const struct ring *r);
*/
LIBBPF_API int ring__consume(struct ring *r);
+/**
+ * @brief **ring__consume_n()** consumes up to a requested amount of items from
+ * a ringbuffer without event polling.
+ *
+ * @param r A ringbuffer object.
+ * @param n Maximum amount of items to consume.
+ * @return The number of items consumed, or a negative number if any of the
+ * callbacks return an error.
+ */
+LIBBPF_API int ring__consume_n(struct ring *r, size_t n);
+
struct user_ring_buffer_opts {
size_t sz; /* size of this struct, for forward/backward compatibility */
};
@@ -418,4 +418,7 @@ LIBBPF_1.4.0 {
} LIBBPF_1.3.0;
LIBBPF_1.5.0 {
+ global:
+ ring__consume_n;
+ ring_buffer__consume_n;
} LIBBPF_1.4.0;
@@ -277,6 +277,33 @@ static int64_t ringbuf_process_ring(struct ring *r, size_t n)
return cnt;
}
+/* Consume available ring buffer(s) data without event polling, up to n
+ * records.
+ *
+ * Returns number of records consumed across all registered ring buffers (or
+ * n, whichever is less), or negative number if any of the callbacks return
+ * error.
+ */
+int ring_buffer__consume_n(struct ring_buffer *rb, size_t n)
+{
+ int64_t err, res = 0;
+ int i;
+
+ for (i = 0; i < rb->ring_cnt; i++) {
+ struct ring *ring = rb->rings[i];
+
+ err = ringbuf_process_ring(ring, n);
+ if (err < 0)
+ return libbpf_err(err);
+ res += err;
+ n -= err;
+
+ if (n == 0)
+ break;
+ }
+ return res;
+}
+
/* Consume available ring buffer(s) data without event polling.
* Returns number of records consumed across all registered ring buffers (or
* INT_MAX, whichever is less), or negative number if any of the callbacks
@@ -378,17 +405,22 @@ int ring__map_fd(const struct ring *r)
return r->map_fd;
}
-int ring__consume(struct ring *r)
+int ring__consume_n(struct ring *r, size_t n)
{
- int64_t res;
+ int res;
- res = ringbuf_process_ring(r, INT_MAX);
+ res = ringbuf_process_ring(r, n);
if (res < 0)
return libbpf_err(res);
return res > INT_MAX ? INT_MAX : res;
}
+int ring__consume(struct ring *r)
+{
+ return ring__consume_n(r, INT_MAX);
+}
+
static void user_ringbuf_unmap_ring(struct user_ring_buffer *rb)
{
if (rb->consumer_pos) {
Introduce a new API to consume items from a ring buffer, limited to a specified amount, and return to the caller the actual number of items consumed. Link: https://lore.kernel.org/lkml/20240310154726.734289-1-andrea.righi@canonical.com/T Signed-off-by: Andrea Righi <andrea.righi@canonical.com> --- tools/lib/bpf/libbpf.h | 12 ++++++++++++ tools/lib/bpf/libbpf.map | 3 +++ tools/lib/bpf/ringbuf.c | 38 +++++++++++++++++++++++++++++++++++--- 3 files changed, 50 insertions(+), 3 deletions(-)