Re: [PATCH] thp: close race between split and zap huge pages

[Kirill A. Shutemov]

On Wed, Apr 16, 2014 at 07:52:29AM +0800, Bob Liu wrote:
> >         *ptl = pmd_lock(mm, pmd);
> > -       if (pmd_none(*pmd))
> > +       if (!pmd_present(*pmd))
> >                 goto unlock;
> 
> But I didn't get the idea why pmd_none() was removed?

!pmd_present(*pmd) is weaker check then pmd_none(*pmd). I mean if
pmd_none(*pmd) is true then pmd_present(*pmd) is always false.
Correct me if I'm wrong.

-- 
 Kirill A. Shutemov
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