On Wed, Nov 21, 2018 at 04:35:34PM -0700, Andy Lutomirski wrote:

quoted

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?

quoted

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.