Re: [PATCH 1/3] Fix COW D-cache aliasing on fork

From: Ralf Baechle
Date: Thu Oct 19 2006 - 14:13:56 EST


On Fri, Oct 20, 2006 at 03:46:35AM +1000, Nick Piggin wrote:

> What about if you just flush the caches after write protecting all
> COW pages? Would that work? Simpler? Better performance? (I don't know)

That would require changing the order of cache flush and tlb flush. To
keep certain architectures that require a valid translation in the TLB
the cacheflush has to be done first. Not sure if those architectures need
a writeable mapping for dirty cachelines - I think hypersparc was one
of them.

Ralf
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