This is the mail archive of the
libc-alpha@sourceware.org
mailing list for the glibc project.
Re: Restartable Sequences system call merged into Linux
- From: Mathieu Desnoyers <mathieu dot desnoyers at efficios dot com>
- To: Florian Weimer <fweimer at redhat dot com>
- Cc: Carlos O'Donell <carlos at redhat dot com>, Peter Zijlstra <peterz at infradead dot org>, "Paul E. McKenney" <paulmck at linux dot vnet dot ibm dot com>, Boqun Feng <boqun dot feng at gmail dot com>, Thomas Gleixner <tglx at linutronix dot de>, linux-kernel <linux-kernel at vger dot kernel dot org>, libc-alpha <libc-alpha at sourceware dot org>
- Date: Mon, 11 Jun 2018 16:04:33 -0400 (EDT)
- Subject: Re: Restartable Sequences system call merged into Linux
- Dkim-filter: OpenDKIM Filter v2.10.3 mail.efficios.com 07DF11BCA1B
- References: <1084280721.10859.1528746558696.JavaMail.zimbra@efficios.com> <31fc101a-295b-067b-1a82-7e9e509fc92f@redhat.com>
----- On Jun 11, 2018, at 3:55 PM, Florian Weimer fweimer@redhat.com wrote:
> On 06/11/2018 09:49 PM, Mathieu Desnoyers wrote:
>> It should be noted that there can be only one rseq TLS area registered per
>> thread,
>> which can then be used by many libraries and by the executable, so this is a
>> process-wide (per-thread) resource that we need to manage carefully.
>
> Is it possible to resize the area after thread creation, perhaps even
> from other threads?
I'm not sure why we would want to resize it. The per-thread area is fixed-size.
Its layout is here: include/uapi/linux/rseq.h: struct rseq
The ABI is designed so that all users (program and libraries) can interact
through this per-thread TLS area.
>
> If there is only one contiguous area, this generally means there needs
> to be linker support, similar to what we have for initial-exec TLS today.
Not entirely sure what you imply by "one contiguous area". All we need is
a single fixed-size TLS area for each thread.
Thanks,
Mathieu
>
> Thanks,
> Florian
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com