Re: [patch 17/18] x86: add hugepagesz option on 64-bit

[Jon Tollefson <kniht@linux.vnet.ibm.com>]

Nishanth Aravamudan wrote:
<snip>
> power would presumably make this 3, to support 64K,16M,16G (and 2, if
> basepage size is 64K).
>
> Another issue for power, though, is that there are local variables in
> arch/powerpc/hugetlbpage.c that depend on the hugepage size in use (and
> since there is only one, they're global). We really want those variables
> to be per-hstate, though, right? The three I see are mmu_huge_psize,
> HPAGE_SHIFT and hugepte_shift. For HPAGE_SHIFT, I think we could just
> switch them over to huge_page_shift(h) given an hstate, but we would
> need to make sure an hstate is available/obtainable at each point? Jon,
> do you have any insight here? I want to make sure struct hstate is
>   
So far I have used the page size or other lookup functions to determine
the hstate
and then use the hstate to get the information I need from it.  For
private functions
I have been passing the hstate around so that it doesn't have to be
looked up each
time.

The only other item of note for power is the huge_pgtable_cache for each
huge page size
that is built based on the value of hugepte_shift.

> future-proofed for other architectures than x86_64...
>
> We probably want to see how converting powerpc looks, then get IA64,
> sparc64 and sh on-board?
>
> Thanks,
> Nish
>
> --
>   
Jon


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