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SubjectRe: [PATCH 1/4] hugetlb, rmap: always use anon_vma root pointer
On Fri, Sep 10, 2010 at 2:50 PM, Andi Kleen <andi@firstfloor.org> wrote:
>> Btw, why isn't the code in __page_set_anon_rmap() also doing this
>> cleaner version (ie a single "if (PageAnon(page)) return;" up front)?
>
> Perhaps I misunderstand the question, but __page_set_anon_rmap
> should handle Anon pages, shouldn't it?

I'm talking about this:

if (!exclusive) {
if (PageAnon(page))
return;
anon_vma = anon_vma->root;
} else {
.. big bad comment ...
if (PageAnon(page))
return;
}

where both sides of the if-statement start off doing the same thing.

It would be much cleaner to just do

... big _comprehensible_ comment ...
if (PageAnon(page))
return;

if (!exclusive)
anon_vma = anon_vma->root;

which avoids that silly else that just does something that we always do.

The reason I reacted is that Naoya-san's patch did that cleaner
version for the hugetlb case. So when I compared it to the non-hugetlb
case I just went "Ewww..."

Linus


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