Re: systemtap & backward compatibility, was Re: [RFC] systemtap: begin the process of using proper kernel APIs

[Adrian Bunk <bunk@kernel.org>]

On Wed, Jul 23, 2008 at 01:34:38PM -0400, Frank Ch. Eigler wrote:
> Hi -
> 
> On Wed, Jul 23, 2008 at 07:54:05PM +0300, Adrian Bunk wrote:
> > On Wed, Jul 23, 2008 at 12:41:37PM -0400, Frank Ch. Eigler wrote:
> > >...
> > > In the interim (before we come up with a way of moving more
> > > kernel-coupled systemtap code into kernel.org/git), would y'all
> > > consider an arrangement?  Those of you who care about systemtap, and
> > > are intending to make an incompatible kernel/module interface change,
> > > please run the systemtap testsuite before & after.  [...]
> 
> > The number of incompatible kernel/module interface changes per
> > kernel is most likely some medium three digit number.  What you have
> > in mind is therefore not really feasible.
> 
> Do you think so, even if the historical pattern continues that only a
> small fraction of those changes actually impact systemtap?

But which are these?

All commits that either remove EXPORT_SYMBOL's or touch include/ are 
candidates would have to be checked, and that's a four digit number
of commits per kernel release.

What is not feasible is to check each of thesse commits.

> > But we have several levels of kernels that incorporate future stuff,
> > from -rc over -next to -mm, and you could implement automated runs
> > of the systemtap testsuite against the latest ones.
> 
> We do some of that already and should do more.
> 
> - FChE

cu
Adrian

-- 

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