Re: [Ksummit-2008-discuss] DTrace

[Evgeniy Polyakov <johnpol@2ka.mipt.ru>]

Hi Frank.

On Sun, Jul 06, 2008 at 11:46:12AM -0400, Frank Ch. Eigler (fche@redhat.com) wrote:
> > We don't add kernel interface for out of tree modules.
> 
> That is a specific example of an attitude that I hope will be
> reexamined if y'all want to support dtrace-level introspection.

I believe the only answer you will get is 'no'. Both for dtrace-like
stuff and ability to add unmaintained interfaces into the kernel.

Out-of-tree stuff can appear and disappear, change its internal
structures, API, ABI and degree of fevered consciousness delirium,
but kernel interface has to be supported long and long time after it was
added, so there is no way to add some interface without its users being
in kernel.

> > And thinking about it - having to compile out of tree kernel modules
> > on the fly to trace user space processes is just braindead.
> 
> I gladly grant "counterintuitive", especially if one's intuition is
> limited to probing just one's own pet user-space process.  It is a
> different matter when one needs to seamlessly probe a mixture of
> kernel activities, daemons, and user processes.
 
Out of curiosity, how in the hell administrator or any other non kernel
hacker person needs to have ability to tap into userspace process via
kernel module?

-- 
	Evgeniy Polyakov