Re: [RFC PATCH for 4.18 00/14] Restartable Sequences

[Daniel Colascione]

On Thu, May 3, 2018 at 9:12 AM Mathieu Desnoyers <
mathieu.desnoyers@xxxxxxxxxxxx> wrote:
> By the way, if we eventually find a way to enhance user-space mutexes in
the
> fashion you describe here, it would belong to another TLS area, and would
> be registered by another system call than rseq. I proposed a more generic
> "TLS area registration" system call a few years ago, but Linus told me he
> wanted a system call that was specific to rseq. If we need to implement
> other use-cases in a TLS area shared between kernel and user-space in a
> similar fashion, the plan is to do it in a distinct system call.

If we proliferate TLS areas; we'd have to register each one upon thread
creation, adding to the overall thread creation path. There's already a
provision for versioning the TLS area. What's the benefit of splitting the
registration over multiple system calls?