Re: [PATCH v2] Add /proc/pid_gen

[Cyrill Gorcunov]

On Wed, Nov 21, 2018 at 04:35:34PM -0700, Andy Lutomirski wrote:
> > 
> > I'm going to have Android's systrace and Perfetto use this approach.
> > Exactly how many tools signed up to use this feature do you need?
> > 
> >> Those people are the intended audience and the
> >> best-positioned reviewers so let's hear from them?
> > 
> > I'm writing plenty of trace analysis tools myself, so I'm part of this
> > intended audience. Other tracing tool authors have told me about
> > out-of-tree hacks for process atomic snapshots via ftrace events. This
> > approach avoids the necessity of these more-invasive hacks.
> 
> Would a tracepoint for pid reuse solve your problem?

FWIW we've had similar problem in criu for memory snapshotting,
because memory data is PID-driven and snapshots are rather
discrete events. So we use task_struct::real_start_time as
a second guard agains pid reuse.