Re: [Ksummit-discuss] [TECH TOPIC] Memory model, using ISO C++11 atomic ops

[David Woodhouse <dwmw2@infradead.org>]

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On Fri, 2016-07-22 at 11:34 +0100, David Howells wrote:
> Further, Paul McKenney and others are assembling a memory model description.
> Do we want to consider loosening up the kernel memory model?

It's not clear that 'loosening up' is what we're after.

In Seoul last year, weren't we looking at things like readl_relaxed()
and lamenting the fact that they do actually still have strong enough
requirements that they can't *really* be very relaxed on Power and
ARM64 at all, because they're basically being used with the assumption
of Intel-like semantics.

The cheap answer is "well, it sucks to be on POWER or ARM64 because
then readl_relaxed() has to be as slow as readl() is".

But it would be good to follow up on that properly, and maybe introduce
a variant which *can* be implemented across more architectures.

Is that what Paul is working on, that you mention above?

-- 
dwmw2

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