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SubjectRe: PATCH: Introduce struct vma_link_info
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On Fri, 2009-03-20 at 10:34 -0300, Luiz Fernando N. Capitulino wrote:
> Andrew,
>
> Currently find_vma_prepare() and low-level VMA functions (eg. __vma_link())
> require callers to provide three parameters to return/pass "link" information
> (pprev, rb_link and rb_parent):
>
> static struct vm_area_struct *
> find_vma_prepare(struct mm_struct *mm, unsigned long addr,
> struct vm_area_struct **pprev, struct rb_node ***rb_link,
> struct rb_node ** rb_parent);
>
> With this patch callers can pass a struct vma_link_info instead:
>
> static struct vm_area_struct *
> find_vma_prepare(struct mm_struct *mm, unsigned long addr,
> struct vma_link_info *link_info);
>
> The code gets simpler and it should be better because less variables
> are pushed into the stack/registers. As shown by the following
> kernel build test:
>
> kernel real user sys
>
> 2.6.29-rc8-vanilla 1136.64 1033.38 82.88
> 2.6.29-rc8-linfo 1135.07 1032.44 82.92
>
> I have also ran hackbench, but I can't understand why its result
> indicates a regression:
>
> kernel Avarage of three runs (25 processes groups)
>
> 2.6.29.rc8-vanilla 2.03
> 2.6.29.rc8-linfo 2.12
>
> Rik has said to me that this could be inside error margin. So, I'm
> submitting the patch for inclusion.
>
> Signed-off-by: Luiz Fernando N. Capitulino <lcapitulino@mandriva.com.br>

I'd rather we look into using the threaded RB-tree to get rid of all
this prev crap.



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