On Thu, May 3, 2018 at 9:12 AM Mathieu Desnoyers < mathieu.desnoy...@efficios.com> 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?