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

----- On May 3, 2018, at 12:22 PM, Daniel Colascione dancol@google.com wrote:

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

quoted

By the way, if we eventually find a way to enhance user-space mutexes in

the

quoted

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?

See the original discussion thread at

https://lkml.org/lkml/2016/4/7/502

Thanks,

Mathieu

-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com