Re: [PATCH v2 1/2] tracing: Move tracepoint callbacks into DEFINE

From: Josh Stone
Date: Fri Aug 21 2009 - 15:35:10 EST


On 08/21/2009 07:47 AM, Ingo Molnar wrote:
>
> * Josh Stone <jistone@xxxxxxxxxx> wrote:
>
>> It's not strictly correct for the tracepoint reg/unreg callbacks
>> to occur when a client is hooking up, because the actual
>> tracepoint may no be present yet. This happens to be fine for
>> syscall, since that's in the core kernel, but it would cause
>> problems for tracepoints defined in a module that hasn't been
>> loaded yet. It also means the reg/unreg has to be EXPORTed for
>> any modules to use the tracepoint (as in SystemTap).
>>
>> This patch removes DECLARE_TRACE_WITH_CALLBACK, and instead
>> introduces DEFINE_TRACE_WITH_CALLBACK which stores the callbacks
>> in struct tracepoint. The callbacks are used now when the active
>> state of the tracepoint changes in set_tracepoint &
>> disable_tracepoint.
>>
>> This also introduces TRACE_EVENT_WITH_CALLBACK, so those events
>> can also provide callbacks if needed.
>
> i think something shorter would be nicer, such as:
>
> DECLARE_TRACE_FN
> TRACE_EVENT_FN

Well I took out the DECLARE_TRACE_ part, but sure, DEFINE_TRACE_FN and
TRACE_EVENT_FN sound fine to me.

Josh
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