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

From: Florian Weimer
Date: Thu Oct 19 2017 - 13:12:55 EST


* 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.