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Subject: Re: [RFC] [PATCH 7/7] Ftrace plugin for Uprobes
From: Peter Zijlstra <peterz@infradead.org>
To: Mark Wielaard <mjw@redhat.com>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>, Ingo Molnar <mingo@elte.hu>,
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Date: Thu, 14 Jan 2010 13:19:56 +0100
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On Thu, 2010-01-14 at 13:16 +0100, Mark Wielaard wrote:
> On Thu, 2010-01-14 at 12:29 +0100, Peter Zijlstra wrote:
> > On Thu, 2010-01-14 at 12:23 +0100, Peter Zijlstra wrote:
> > > On Mon, 2010-01-11 at 17:56 +0530, Srikar Dronamraju wrote:
> > > > This patch implements ftrace plugin for uprobes.
> > > 
> > > Right, like others have said, trace events is a much saner interface.
> > > 
> > > So the easiest way I can see that working is to register uprobes against
> > > a file (not a pid).
> > 
> > Just to clarify, this means you can do things like:
> > 
> >  p:uprobe_event dso:symbol[+offs]
> > 
> > Irrespective of whether there are any current user of that file.
> 
> Yes, that is a good idea, you can then also refine that with a filter on
> a target pid. That is what systemtap also does, you define files
> (whether they are executables or shared libraries, etc) plus
> symbols/offsets/etc as targets and monitor when they get mapped in
> (either system wide, per executable or pid based).

Well, the pid part is more the concern of the consumer of the
trace-event. The event itself is task invariant and only cares about the
particular code in question getting executed.