LKML Archive on lore.kernel.org
help / color / mirror / Atom feed
From: Florian Weimer <fweimer@redhat.com>
To: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Carlos O'Donell <carlos@redhat.com>,
	Peter Zijlstra <peterz@infradead.org>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>,
	Boqun Feng <boqun.feng@gmail.com>,
	Thomas Gleixner <tglx@linutronix.de>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	libc-alpha <libc-alpha@sourceware.org>
Subject: Re: Restartable Sequences system call merged into Linux
Date: Tue, 12 Jun 2018 15:11:35 +0200	[thread overview]
Message-ID: <091061df-3482-8762-30e4-feaf3417be11@redhat.com> (raw)
In-Reply-To: <305409897.10888.1528747473727.JavaMail.zimbra@efficios.com>

On 06/11/2018 10:04 PM, Mathieu Desnoyers wrote:
> ----- 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

Looks I was mistaken and this is very similar to the robust mutex list.

Should we treat it the same way?  Always allocate it for each new thread 
and register it with the kernel?

> The ABI is designed so that all users (program and libraries) can interact
> through this per-thread TLS area.

Then the user code needs just the address of the structure.

How much coordination is needed between different users of this 
interface?  Looking at the the section hacks, I don't think we want to 
put this into glibc at this stage.  It looks more like something for 
which we traditionally require compiler support.

Thanks,
Florian

  reply	other threads:[~2018-06-12 13:11 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-06-11 19:49 Mathieu Desnoyers
2018-06-11 19:55 ` Florian Weimer
2018-06-11 20:04   ` Mathieu Desnoyers
2018-06-12 13:11     ` Florian Weimer [this message]
2018-06-12 16:31       ` Mathieu Desnoyers
2018-06-13  8:21         ` Florian Weimer
2018-06-14 12:27         ` Pavel Machek
2018-06-14 13:01           ` Mathieu Desnoyers
2018-06-14 13:25             ` Pavel Machek
2018-06-14 13:32               ` Florian Weimer
2018-06-14 13:46                 ` Mathieu Desnoyers
2018-06-15  5:10                   ` Florian Weimer
2018-06-15 17:44                     ` Mathieu Desnoyers
2018-06-14 13:38               ` Mathieu Desnoyers
2018-06-14 13:49                 ` Pavel Machek
2018-06-14 14:00                   ` Florian Weimer
2018-06-14 14:36                     ` Mathieu Desnoyers
2018-06-14 14:41                       ` Florian Weimer
2018-06-14 15:09                         ` Mathieu Desnoyers
2018-06-15  5:09             ` Florian Weimer
2018-06-15 17:50               ` Mathieu Desnoyers
2018-06-15  5:07           ` Florian Weimer
2018-06-13 11:48 ` Heiko Carstens
2018-06-13 16:14   ` Mathieu Desnoyers
2018-06-13 19:53     ` Mathieu Desnoyers

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=091061df-3482-8762-30e4-feaf3417be11@redhat.com \
    --to=fweimer@redhat.com \
    --cc=boqun.feng@gmail.com \
    --cc=carlos@redhat.com \
    --cc=libc-alpha@sourceware.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mathieu.desnoyers@efficios.com \
    --cc=paulmck@linux.vnet.ibm.com \
    --cc=peterz@infradead.org \
    --cc=tglx@linutronix.de \
    --subject='Re: Restartable Sequences system call merged into Linux' \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).