Messages in this thread | | | Subject | Re: [PATCH v3 2/3] bpf: Implement function bpf_perf_event_read() that get the selected hardware PMU conuter | From | Alexei Starovoitov <> | Date | Thu, 23 Jul 2015 15:56:57 -0700 |
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On 7/23/15 2:42 AM, Kaixu Xia wrote: > According to the perf_event_map_fd and index, the function > bpf_perf_event_read() can convert the corresponding map > value to the pointer to struct perf_event and return the > Hardware PMU counter value. > > Signed-off-by: Kaixu Xia <xiakaixu@huawei.com> ... > +static u64 bpf_perf_event_read(u64 r1, u64 index, u64 r3, u64 r4, u64 r5) > +{ > + struct bpf_map *map = (struct bpf_map *) (unsigned long) r1; > + struct bpf_array *array = container_of(map, struct bpf_array, map); > + struct perf_event *event; > + > + if (index >= array->map.max_entries) > + return -E2BIG; > + > + event = array->events[index]; > + if (!event) > + return -EBADF;
probably ENOENT makes more sense here.
> + > + if (event->state != PERF_EVENT_STATE_ACTIVE) > + return -ENOENT;
and -EINVAL here?
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