Re: [PATCH v8 2/8] Add rseq extensible ABI support

[DJ Delorie <dj@redhat.com>]

Michael Jeanson <mjeanson@efficios.com> writes:
> When rseq registration is disabled by tunable we still need to allocate 
> an rseq block because application code is allowed to check for the 
> registration status by reading 'rseq->cpu_id'. So in this case we 
> allocate the minimum ABI size of 32.

Ok, I admit that was confusing ;-)

> Internally this is recorded in 'dl_tls_rseq_size' but the application
> visible '_rseq_size' is left at 0 (this happens in
> sysdeps/nptl/dl-tls_init_tp.c).

A comment in sysdeps/nptl/dl-tls_init_tp.c after the if{} noting what
the variables would be otherwise might be useful.  At least that was one
of the places I looked at when trying to figure this out.

> I'll try making this more clear with additional comments and finding a 
> name for 'rseq_size' that is not so close to '__rseq_size'.

Perhaps "rseq_alloc_size" ?