Re: [PATCH net-next 2/2] samples/bpf: add samples for HW_CACHE / RAW events

[Alexei Starovoitov]

On 5/22/17 4:26 PM, David Miller wrote:

From: Alexei Starovoitov <a...@fb.com>
Date: Mon, 22 May 2017 15:48:40 -0700

@@ -31,7 +31,7 @@ static unsigned long long (*bpf_get_current_uid_gid)(void) =
        (void *) BPF_FUNC_get_current_uid_gid;
 static int (*bpf_get_current_comm)(void *buf, int buf_size) =
        (void *) BPF_FUNC_get_current_comm;
-static int (*bpf_perf_event_read)(void *map, int index) =
+static u64 (*bpf_perf_event_read)(void *map, u64 flags) =
        (void *) BPF_FUNC_perf_event_read;

If the second argument really is "u64 flags", then please update
the comments in tools/include/uapi/linux/bpf.h as well.

of course.
As independent patch, I assume.
For both tools/include/uapi/...bpf.h and include/uapi/...bpf.h

It has some info:
/* BPF_FUNC_perf_event_output and BPF_FUNC_perf_event_read flags. */
#define BPF_F_INDEX_MASK                0xffffffffULL
#define BPF_F_CURRENT_CPU               BPF_F_INDEX_MASK

yet perf_event_read() is least documented. hmm.
 * u64 bpf_perf_event_read(&map, index)
 *     Return: Number events read or error code

that needs to be fixed.