Re: [PATCH v3 11/19] unwind: Add deferred user space unwinding API

On Wed, Oct 30, 2024 at 10:47:55AM -0700, Josh Poimboeuf wrote:
> > Moving from per-cpu to per-task makes this cookie task-specific and not
> > global anymore, I don't think we want this for a stack walking
> > infrastructure meant to be used by various tracers. Also a global cookie
> > is more robust and does not depend on guaranteeing that all the
> > trace data is present to guarantee current thread ID accuracy and
> > thus that cookies match between deferred unwind request and their
> > fulfillment.
> 
> I don't disagree.  What I meant was, on entry (or exit), increment the
> task cookie *with* the CPU bits included.
> 
> Or as you suggested previously, the "cookie" just be a struct with two
> fields: CPU # and per-task entry counter.

Never mind, that wouldn't work...  Two tasks could have identical
per-task counters while being scheduled on the same CPU.

-- 
Josh