Re: [PATCH 3/3] xfs: convert buffer cache to use high order folios

Dave Chinner
2024-01-22T11:57:50Z

On Sun, Jan 21, 2024 at 10:45:55PM -0800, Christoph Hellwig wrote:
> > + int length = BBTOB(bp->b_length);
> > + int order;
> > +
> > + order = ilog2(length);
> > + if ((1 << order) < length)
> > + order = ilog2(length - 1) + 1;
> > +
> > + if (order <= PAGE_SHIFT)
> > + order = 0;
> > + else
> > + order -= PAGE_SHIFT;
>
> Shouldn't this simply use get_order()?

Huh. Yes, it should.

I went looking for a helper and didn't find one in the mm or folio
code. Now you point it out, I find that it is in it's own asm header
(include/asm-generic/getorder.h) so it's no wonder I didn't find
it.

Why is it in include/asm-generic? There's nothing asm related
to that function or it's implementation....

-Dave.
--
Dave Chinner
david@fromorbit.com