Re: [PATCH v3 4/5] x86/mm: optimize static_protection() by using overlap()

From: Thomas Gleixner
Date: Fri Sep 07 2018 - 04:22:01 EST


On Fri, 7 Sep 2018, Yang, Bin wrote:
> On Fri, 2018-09-07 at 09:49 +0200, Thomas Gleixner wrote:
> > On Fri, 7 Sep 2018, Yang, Bin wrote:
> > > On Tue, 2018-09-04 at 14:22 +0200, Thomas Gleixner wrote:
> > >
> > > I just write a test.c to compare the result between overlap() and
> > > original within().
> >
> > You are right. Your version of doing the overlap exclusive works. I misread
> > the conditions. I still prefer doing inclusive checks because they are way
> > more obvious.
>
> I am sorry for my poor english. What is "inclusive checks"?

Exlusive: val >= start && val < end

Inclusive: val >= start && val <= end

So the difference is that you feed exclusive with:

end = start + size

and inclusive with

end = start + size - 1

Thanks,

tglx