[PATCH] Linux: Implement membarrier function

[Mathieu Desnoyers]

----- 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