Re: [RFC PATCH v9 for 4.15 01/14] Restartable sequences system call

* Mathieu Desnoyers:

Speaking of optimization, I think the rseq.c helper library
(and eventually glibc) should define the __rseq_abi TLS
variable with __attribute__((tls_model("initial-exec"))).
It provides faster, and signal-safe, accesses to the TLS
variable from libraries.

The idea you were suggesting where the application could
override the glibc symbol with its own just ends up enforcing
an initial-exec model, but it looks like we can do this
directly from the library.

This really depends on how the programming model turns out once
multiple libraries are involved.  I think it's premature to discuss
such details.