Re: [for-next][PATCH 1/5] tracepoint: Give priority to probes of tracepoints

[Mathieu Desnoyers]

----- On Oct 30, 2015, at 4:25 PM, rostedt rostedt@xxxxxxxxxxx wrote:

> On Thu, 29 Oct 2015 17:52:16 +0000 (UTC)
> Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> wrote:
> 
>> ----- On Oct 29, 2015, at 3:07 AM, rostedt rostedt@xxxxxxxxxxx wrote:
>> 
>> > From: "Steven Rostedt (Red Hat)" <rostedt@xxxxxxxxxxx>
>> > 
>> > In order to guarantee that a probe will be called before other probes that
>> > are attached to a tracepoint, there needs to be a mechanism to provide
>> > priority of one probe over the others.
>> > 
>> > Adding a prio field to the struct tracepoint_func, which lets the probes be
>> > sorted by the priority set in the structure. If no priority is specified,
>> > then a priority of 10 is given (this is a macro, and perhaps may be changed
>> > in the future).
>> > 
>> > Now probes may be added to affect other probes that are attached to a
>> > tracepoint with a guaranteed order.
>> > 
>> > One use case would be to allow tracing of tracepoints be able to filter by
>> > pid. A special (higher priority probe) may be added to the sched_switch
>> > tracepoint and set the necessary flags of the other tracepoints to notify
>> > them if they should be traced or not. In case a tracepoint is enabled at the
>> > sched_switch tracepoint too, the order of the two are not random.
>> > 
>> > Cc: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
>> > Signed-off-by: Steven Rostedt <rostedt@xxxxxxxxxxx>
>> 
>> Sounds good to me,
>> 
>> Acked-by: Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx>
>> 
> 
> Thanks.
> 
> Unfortunately I already pushed it out to linux-next (had a deadline),
> otherwise I could have added your ack. I'm guessing you missed the RFC
> version I posted a week ago.

No worries,

I've seen it, but was busy with other stuff.

Thanks,

Mathieu

> 
> -- Steve

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com
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