Messages in this thread | | | Subject | Re: New resources - pls, explain :-( | Date | Fri, 13 Aug 1999 13:57:57 +0100 (BST) | From | Alan Cox <> |
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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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