Re: [PATCHv11 2.6.36-rc2-tip 10/15] 10: tracing: config option to enable both kprobe-tracer and uprobe-tracer.

[Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>]

(2010/08/27 18:31), Srikar Dronamraju wrote:
>>>  config PROBE_EVENTS
>>> -	def_bool n
>>> +	bool "Enable kprobes and uprobe based dynamic events"
>>> +	select TRACING
>>> +	default n
>>
>> Hmm, without this series, KPROBE_EVENT is set "y" by default.
>> (PROBE_EVENTS is introduced by 8/15)
>> I'd like to set this "y" by default, because it doesn't
>> affect other parts.
>>
>> Thank you,
>>
> 
> This is based on what we discussed here
> http://lkml.org/lkml/2010/8/2/86.
> 
> To recollect, 
> Frederic wanted that there should be one option to select both
> UPROBE_EVENT and KPROBE_EVENT. 
> 
> However if we make PROBE_EVENTS (which is the option to enable both
> events) default "Y", then both UPROBE_EVENT and KPROBE_EVENT will be
> selected.
> 
> Also if we look at http://lkml.org/lkml/2010/6/21/160, Steven
> Rostedt didnt want UPROBE_EVENT to selected by default.
> 
> I agree that we should keep UPROBE_EVENT to be 'default n' till it gets
> tested. Hence we have two choices. Either set the common knob to be
> 'default n' or dont have the common knob for now (i.e drop this
> patch for now).
> 
> I think we should go with the first one, i.e have a common knob thats
> by default unselected.

Yeah, I'm OK to have a common knob, but I just don't like to set
KPROBE_EVENT unselected by default. I think there is no reason
to change default selecting (currently, KPROBE_EVENT=y by default.)

So, I think we should have below selecting list;
--- Tracers
...
[*] Enable dynamic events
   [ ] Enable user-space dynamic events (EXPERIMENTAL)
...

What would you think about this ? :)

Thank you,


-- 
Masami HIRAMATSU
2nd Dept. Linux Technology Center
Hitachi, Ltd., Systems Development Laboratory
E-mail: masami.hiramatsu.pt@hitachi.com