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Re: [PATCH v2 2.6.38-rc8-tip 0/20] 0: Inode based uprobes
- From: Thomas Gleixner <tglx at linutronix dot de>
- To: Srikar Dronamraju <srikar at linux dot vnet dot ibm dot com>
- Cc: "Frank Ch. Eigler" <fche at redhat dot com>, Andrew Morton <akpm at linux-foundation dot org>, int-list-linux-mm at kvack dot org, linux-mm at kvack dot org, Peter Zijlstra <peterz at infradead dot org>, Ingo Molnar <mingo at elte dot hu>, Steven Rostedt <rostedt at goodmis dot org>, Arnaldo Carvalho de Melo <acme at infradead dot org>, Linus Torvalds <torvalds at linux-foundation dot org>, Masami Hiramatsu <masami dot hiramatsu dot pt at hitachi dot com>, Christoph Hellwig <hch at infradead dot org>, Ananth N Mavinakayanahalli <ananth at in dot ibm dot com>, Andi Kleen <andi at firstfloor dot org>, Oleg Nesterov <oleg at redhat dot com>, Jim Keniston <jkenisto at linux dot vnet dot ibm dot com>, SystemTap <systemtap at sources dot redhat dot com>, LKML <linux-kernel at vger dot kernel dot org>, "Paul E. McKenney" <paulmck at linux dot vnet dot ibm dot com>
- Date: Tue, 15 Mar 2011 12:02:45 +0100 (CET)
- Subject: Re: [PATCH v2 2.6.38-rc8-tip 0/20] 0: Inode based uprobes
- References: <20110314133403.27435.7901.sendpatchset@localhost6.localdomain6> <20110314163028.a05cec49.akpm@linux-foundation.org> <y0maagxuqx6.fsf@fche.csb> <alpine.LFD.2.00.1103150224260.2787@localhost6.localdomain6> <20110315052133.GT24254@linux.vnet.ibm.com>
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