Re: [PATCH 1/5] ftrace: use module notifier for function tracer

[Masami Hiramatsu <mhiramat@redhat.com>]

Tim Abbott wrote:
> On Wed, 22 Apr 2009, Ingo Molnar wrote:
> 
>> I suspect ksplice could make use of text_mutex?
> 
> Yes, this is what I was imagining.  Thanks for pointing this out!  I plan 
> to make Ksplice use this for the next version of the Ksplice patch series.

Could you also add "use text_poke() on x86" to your plan? :-)

> However, since Ksplice can be built as a module, we'll want to 
> EXPORT_SYMBOL_GPL(text_mutex).  The comment above text_mutex's definition 
> suggests some people would prefer not to have modules patching the kernel 
> text, and so this point might be contentious.  I've found support for 
> building Ksplice as a module to be a useful feature in case one needs to 
> use multiple different versions of Ksplice on the same system (e.g. 
> because the version built in to the kernel doesn't support a particular 
> patch).

Hmm, I can't agree that we allow module to modify kernel text...
Is that possible to separate kernel-text swapping routine from Ksplice
module? In that case, we don't need to export text_mutex.

Thank you,

-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America) Inc.
Software Solutions Division

e-mail: mhiramat@redhat.com