Re: RFC: COW for hugepages

[Andi Kleen]

On Wed, 7 Apr 2004 17:42:39 +1000
David Gibson <david@xxxxxxxxxxxxxxxxxxxxx> wrote:

> Currently the kernel does not implement copy-on-write for huge pages -
> in fact any sort of page fault on a hugepage results in a SIGBUS.
> This means that hugepages *always* have MAP_SHARED semantics, even if
> MAP_PRIVATE is requested, and in particular that they are always
> shared across a fork().  Particularly when using hugetlbfs as just a
> source of quasi-anonymous memory, those are rather strange semantics.

[...]

Implementing this for ppc64 only is just wrong. Before you do this 
I would suggest to factor out the common code in the various hugetlbpage
implementations and then implement it in common code.

-Andi
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