Re: [PATCH 1/1] hugetlbfs: handle pages higher order than MAX_ORDER

[Nick Piggin]

On Wednesday 08 October 2008 20:33, Andy Whitcroft wrote:
> When working with hugepages, hugetlbfs assumes that those hugepages
> are smaller than MAX_ORDER.  Specifically it assumes that the mem_map
> is contigious and uses that to optimise access to the elements of the
> mem_map that represent the hugepage.  Gigantic pages (such as 16GB pages
> on powerpc) by definition are of greater order than MAX_ORDER (larger
> than MAX_ORDER_NR_PAGES in size).  This means that we can no longer make
> use of the buddy alloctor guarentees for the contiguity of the mem_map,
> which ensures that the mem_map is at least contigious for maximmally
> aligned areas of MAX_ORDER_NR_PAGES pages.
>
> This patch adds new mem_map accessors and iterator helpers which handle
> any discontiguity at MAX_ORDER_NR_PAGES boundaries.  It then uses these
> within copy_huge_page, clear_huge_page, and follow_hugetlb_page to allow
> these to handle gigantic pages.
>
> Signed-off-by: Andy Whitcroft <apw@xxxxxxxxxxxx>

Seems good to me... but do you have to add lots of stuff into the end of
the for statements? Why not just at the end of the block?
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/