Add ring__avail_data_size for querying the currently available data in
the ringbuffer, similar to the BPF_RB_AVAIL_DATA flag in
bpf_ringbuf_query. This is racy during ongoing operations but is still
useful for overall information on how a ringbuffer is behaving.
Signed-off-by: Martin Kelly <martin.kelly@xxxxxxxxxxxxxxx>
---
tools/lib/bpf/libbpf.h | 11 +++++++++++
tools/lib/bpf/libbpf.map | 1 +
tools/lib/bpf/ringbuf.c | 5 +++++
3 files changed, 17 insertions(+)
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index 935162dbb3bf..87e3bad37737 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -1279,6 +1279,17 @@ LIBBPF_API unsigned long ring__consumer_pos(const struct ring *r);
*/
LIBBPF_API unsigned long ring__producer_pos(const struct ring *r);
+/**
+ * @brief **ring__avail_data_size()** returns the number of bytes in this
+ * ringbuffer not yet consumed. This has no locking associated with it, so it
+ * can be inaccurate if operations are ongoing while this is called. However, it
+ * should still show the correct trend over the long-term.
+ *
+ * @param r A ring object.
+ * @return The number of bytes not yet consumed.
+ */
+LIBBPF_API size_t ring__avail_data_size(const struct ring *r);
+
struct user_ring_buffer_opts {
size_t sz; /* size of this struct, for forward/backward compatibility */
};
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 1c532fe7a445..f66d7f0bc224 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -401,6 +401,7 @@ LIBBPF_1.3.0 {
bpf_program__attach_tcx;
bpf_program__attach_uprobe_multi;
ring_buffer__ring;
+ ring__avail_data_size;
ring__consumer_pos;
ring__producer_pos;
} LIBBPF_1.2.0;
diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
index 54c596db57a4..f51ad1af6ab8 100644
--- a/tools/lib/bpf/ringbuf.c
+++ b/tools/lib/bpf/ringbuf.c
@@ -350,6 +350,11 @@ unsigned long ring__producer_pos(const struct ring *r)
return smp_load_acquire(r->producer_pos);
}
+size_t ring__avail_data_size(const struct ring *r)
+{
+ return ring__producer_pos(r) - ring__consumer_pos(r);
+}
+
static void user_ringbuf_unmap_ring(struct user_ring_buffer *rb)
{
if (rb->consumer_pos) {
--
2.34.1
