On 2015/10/13 3:29, Alexei Starovoitov wrote:
On 10/12/15 2:02 AM, Kaixu Xia wrote:
+extern const struct bpf_func_proto bpf_perf_event_sample_enable_proto;
+extern const struct bpf_func_proto bpf_perf_event_sample_disable_proto;
externs are unnecessary. Just make them static.
Also I prefer single helper that takes a flag, so we can extend it
instead of adding func_id for every little operation.
To avoid conflicts if you touch kernel/bpf/* or bpf.h please always
base your patches of net-next.
> + atomic_set(&map->perf_sample_disable, 0);
global flag per map is no go.
events are independent and should be treated as such.
Then how to avoid racing? For example, when one core disabling all events
in a map, another core is enabling all of them. This racing may causes
sereval
perf events in a map dump samples while other events not. To avoid such
racing
I think some locking must be introduced, then cost is even higher.
The reason why we introduce an atomic pointer is because each operation
should
controls a set of events, not one event, due to the per-cpu manner of
perf events.
Thank you.
Please squash these two patches, since they're part of one logical
feature. Splitting them like this only makes review harder.
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