| Message ID | 1444981333-70429-3-git-send-email-xiakaixu@huawei.com |
|---|---|
| State | New |
| Headers | show |
On 10/16/15 12:42 AM, Kaixu Xia wrote: > This patch implements the function that controlling all the perf > events stored in PERF_EVENT_ARRAY maps by setting the parameter > 'index' to maps max_entries. > > Signed-off-by: Kaixu Xia <xiakaixu@huawei.com> > --- > kernel/trace/bpf_trace.c | 20 ++++++++++++++++++-- > 1 file changed, 18 insertions(+), 2 deletions(-) > > diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c > index 3175600..4b385863 100644 > --- a/kernel/trace/bpf_trace.c > +++ b/kernel/trace/bpf_trace.c > @@ -229,13 +229,30 @@ static u64 bpf_perf_event_dump_control(u64 r1, u64 index, u64 flag, u64 r4, u64 > 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; > + int i; > > - if (unlikely(index >= array->map.max_entries)) > + if (unlikely(index > array->map.max_entries)) > return -E2BIG; > > if (flag & BIT_FLAG_CHECK) > return -EINVAL; > > + if (index == array->map.max_entries) { I don't like in-band signaling like this, since it's easy to make mistake on the bpf program side. Please use 2nd bit of 'flags' for that instead. Also squash this patch into 1st. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
diff --git a/kernel/trace/bpf_trace.c b/kernel/trace/bpf_trace.c index 3175600..4b385863 100644 --- a/kernel/trace/bpf_trace.c +++ b/kernel/trace/bpf_trace.c @@ -229,13 +229,30 @@ static u64 bpf_perf_event_dump_control(u64 r1, u64 index, u64 flag, u64 r4, u64 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; + int i; - if (unlikely(index >= array->map.max_entries)) + if (unlikely(index > array->map.max_entries)) return -E2BIG; if (flag & BIT_FLAG_CHECK) return -EINVAL; + if (index == array->map.max_entries) { + bool dump_control = flag & BIT_DUMP_CTL; + + for (i = 0; i < array->map.max_entries; i++) { + event = (struct perf_event *)array->ptrs[i]; + if (!event) + continue; + + if (dump_control) + atomic_dec_if_positive(&event->dump_enable); + else + atomic_inc_unless_negative(&event->dump_enable); + } + return 0; + } + event = (struct perf_event *)array->ptrs[index]; if (!event) return -ENOENT; @@ -244,7 +261,6 @@ static u64 bpf_perf_event_dump_control(u64 r1, u64 index, u64 flag, u64 r4, u64 atomic_dec_if_positive(&event->dump_enable); else atomic_inc_unless_negative(&event->dump_enable); - return 0; }
This patch implements the function that controlling all the perf events stored in PERF_EVENT_ARRAY maps by setting the parameter 'index' to maps max_entries. Signed-off-by: Kaixu Xia <xiakaixu@huawei.com> --- kernel/trace/bpf_trace.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-)