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SubjectRe: New resources - pls, explain :-(
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> (I exaggerate.  Alan Cox said that not reordering was a safer default
> (which is essentially my position) and Dave Miller said to me in
> private email something along the lines that any sane architecture has
> a side-effect bit in the PTEs to prevent reordering of accesses to
> certain pages.)

How many insane architectures are there in the world though.

> this: ncr, aic7xxx, tulip, epic100. How many others would there be in
> this category? It sounds to me like the vast majority of drivers
> which use readl/writel would be assuming that they prevent reordering.

I think that is fairly accurate.

> My position is that readl/writel should prevent reordering (of the
> accesses generated by read*/write*), and that we should have variants,
> maybe called readl_fast etc., for the cases where performance is
> crucial and the driver writer is willing to put in explicit barriers
> where necessary.

Agreed


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