Re: [PATCH v2 2.6.38-rc8-tip 0/20] 0: Inode based uprobes

Thomas Gleixner
2011-03-15T11:04:14Z

On Tue, 15 Mar 2011, Srikar Dronamraju wrote:
> > > TODO: Documentation/trace/uprobetrace.txt
> >
> > without a reasonable documentation how to use that is a brilliant
> > argument?
>
> We had a fairly decent documentation for uprobes and
> uprobetracer. But that had to be changed with the change in
> underlying design of uprobes infrastructure. Since uprobetrace is one
> the user interface, I plan to document it soon. However it would be
> great if we had inputs on how we should be designing the syscall.

Ok.

> > Or some sensible implementation ?
>
> Would syscall based perf probe implementation count as a sensible
> implementation? My current plan was to code up the perf probe for

Yes.

> uprobes and then draft a proposal for how the syscall should look.
> There are still some areas on how we should be allowing the
> filter, and what restrictions we should place on the syscall
> defined handler. I would like to hear from you and others on your
> ideas for the same. If you have ideas on doing it other than using a
> syscall then please do let me know about the same.

I don't think that anything else than a proper syscall interface is
going to work out.

> I know that getting the user interface right is very important.
> However I think it kind of depends on what the infrastructure can
> provide too. So if we can decide on the kernel ABI and the
> underlying design (i.e can we use replace_page() based background page
> replacement, Are there issues with the Xol slot based mechanism that
> we are using, etc), we can work towards providing a stable User ABI that
> even normal users can use. For now I am concentrating on getting the
> underlying infrastructure correct.

Fair enough. I'll go through the existing patchset and comment there.

Thanks,

tglx