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Re: [PATCH] Linux: Implement membarrier function
- From: Mathieu Desnoyers <mathieu dot desnoyers at efficios dot com>
- To: Florian Weimer <fweimer at redhat dot com>
- Cc: Torvald Riegel <triegel at redhat dot com>, libc-alpha <libc-alpha at sourceware dot org>, "Paul E. McKenney" <paulmck at linux dot vnet dot ibm dot com>
- Date: Thu, 29 Nov 2018 09:44:22 -0500 (EST)
- Subject: Re: [PATCH] Linux: Implement membarrier function
- Dkim-filter: OpenDKIM Filter v2.10.3 mail.efficios.com 09D6C9D3E4
- References: <8736rldyzm.fsf@oldenburg.str.redhat.com> <1543444466.5493.220.camel@redhat.com> <87y39c2dsg.fsf@oldenburg.str.redhat.com>
----- On Nov 29, 2018, at 8:50 AM, Florian Weimer fweimer@redhat.com wrote:
> * Torvald Riegel:
>
>> On Wed, 2018-11-28 at 16:05 +0100, Florian Weimer wrote:
>>> This is essentially a repost of last year's patch, rebased to the glibc
>>> 2.29 symbol version and reflecting the introduction of
>>> MEMBARRIER_CMD_GLOBAL.
>>>
>>> I'm not including any changes to manual/ here because the set of
>>> supported operations is evolving rapidly, we could not get consensus for
>>> the language I proposed the last time, and I do not want to contribute
>>> to the manual for the time being.
>>
>> Fair enough. Nonetheless, can you summarize how far you're along with
>> properly defining the semantics (eg, based on the C/C++ memory model)?
>
> I wrote down what you could, but no one liked it.
>
> <https://sourceware.org/ml/libc-alpha/2017-12/msg00796.html>
>
> I expect that a formalization would interact in non-trivial ways with
> any potential formalization of usable relaxed memory order semantics,
> and I'm not sure if anyone knows how to do the latter today.
Adding Paul E. McKenney in CC.
Thanks,
Mathieu
>
> Thanks,
> Florian
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com