Commit 3b34d297 authored by Martin Kelly's avatar Martin Kelly Committed by Andrii Nakryiko
Browse files

libbpf: Add ring__avail_data_size 



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: default avatarMartin Kelly <martin.kelly@crowdstrike.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/bpf/20230925215045.2375758-8-martin.kelly@crowdstrike.com
parent b18db871

tools/lib/bpf/libbpf.h

+11 −0
Original line number Diff line number Diff line
@@ -1282,6 +1282,17 @@ 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 the

 * 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 ringbuffer 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 */

};

tools/lib/bpf/libbpf.map

+1 −0
Original line number Diff line number Diff line
@@ -400,6 +400,7 @@ LIBBPF_1.3.0 { 
		bpf_program__attach_netfilter;

		bpf_program__attach_tcx;

		bpf_program__attach_uprobe_multi;

		ring__avail_data_size;

		ring__consumer_pos;

		ring__producer_pos;

		ring_buffer__ring;

tools/lib/bpf/ringbuf.c

+9 −0
Original line number Diff line number Diff line
@@ -352,6 +352,15 @@ 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)

{

	unsigned long cons_pos, prod_pos;



	cons_pos = ring__consumer_pos(r);

	prod_pos = ring__producer_pos(r);

	return prod_pos - cons_pos;

}



static void user_ringbuf_unmap_ring(struct user_ring_buffer *rb)

{

	if (rb->consumer_pos) {