[ltt-dev] [PATCH v3] lttng: remove ltt root directory if it's no needed

[compudj@krystal.dyndns.org (Mathieu Desnoyers)]

* KOSAKI Motohiro (kosaki.motohiro at jp.fujitsu.com) wrote:
> > We have to cleanup the lttng's root directory of debugfs if 
> > there is nobody uses it any more. Because any related lttng
> > modules are unloaded, no need to keep this directory.
> > 
> > This patch is based on 2.6.29-rc3-lttng-0.92.
> 
> hmhm. There is one meta question.
> 
> Why do we need ltt-control unloadability?
> We expect merge lttng into mainline in nearly future.
> 
> At that time, Who need ltt core kernel module (not any specific probe).
> 
> IOW, why ca't we do following?
> 

The main argument would be that on embedded systems with few memory,
some might want to leave the tracer unloaded until they need it.

Having the whole tracer available as modules makes that possible. If
it's built into the kernel, one has to leave some memory to the tracer
code and data structures even when unneeded. This is why I opted for a
fully modular design for LTTng.

> 
> config LTT_TRACE_CONTROL
> -        tristate "Linux Trace Toolkit Trace Controller"
> +        bool "Linux Trace Toolkit Trace Controller"
>         depends on LTT_TRACER
>         default m

and that would be default y :-)

Mathieu

>         help
>           If you enable this option, the debugfs-based Linux Trace Toolkit Trace
>           Controller will be either built in the kernel or as module.
> 
> 
> 
> 
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-- 
Mathieu Desnoyers
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