Re: [GIT PULL] tracing: make signal tracepoints more useful

From: Ingo Molnar
Date: Wed Jan 18 2012 - 06:59:50 EST



* Oleg Nesterov <oleg@xxxxxxxxxx> wrote:

> On 01/17, Ingo Molnar wrote:
> >
> > Any tool that requests the signal trace event, and copies
> > the full (and now larger) record it got in the ring-buffer,
> > without expanding the target record's size accordingly will
> > *BREAK*.
> >
> > I do not claim that tools will break in practice - i'm
> > raising the *possibility* out of caution and i'm frustrated
> > that you *STILL* don't understand how ABIs are maintained in
> > Linux.
>
> OK, but what if we rename the tracepoint?
>
> IOW, add the new tracepoint and remove the old one. Of course,
> this can confuse the users of the current "signal_generate",
> but this is safe. b413d48a does this...
>
> Or this is not allowed too?

Everything is allowed that makes sense and does not break apps,
with a strong preference towards the simplest possible variant.

I.e. your patch.

Thanks,

Ingo
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