Re: [GIT PULL] uprobes: pre-filtering

From: Ingo Molnar
Date: Fri Jan 25 2013 - 13:45:55 EST



* Oleg Nesterov <oleg@xxxxxxxxxx> wrote:

> On 01/25, Ingo Molnar wrote:
> >
> > * Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx> wrote:
> >
> > > The other alternative is to extend the current abi and pass
> > > the prefilter option. Should we extend the abi for userspace
> > > tracing is obviously debatable.
> >
> > That's the obvious path to go - why add something to the kernel
> > if user-space cannot make use of it?
>
> This is what I am going to (try to) do, but I am not sure if this makes
> sense...
>
> For the start, can't we teach 'uprobe_events' file to accept, say,
>
> 'p file:0x1234 pid=1 other-opts'
>
> for the start? This looks simple enough, and I after looked
> into tools/perf it seems that perf can be changed too.
>
> What do you think?

Sounds sensible and functional to me.

> Then we can extend 'pid=' option to accept the list of pids,
> perhaps.
>
> In the long term we probably need uprobes/pid_filter or
> something like this, it should allow to add/del pid
> dynamically. I really do not know.

For now removing+adding a new one should be enough to 'change' a
uprobe, right?

Thanks,

Ingo
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