Messages in this thread | | | Date | Tue, 23 Jan 2018 15:47:00 -0600 | From | Segher Boessenkool <> | Subject | Re: [PATCH v2 1/5] powerpc/mm: Enhance 'slice' for supporting PPC32 |
| |
On Mon, Jan 22, 2018 at 08:52:53AM +0100, Christophe LEROY wrote: > >Just make sure to declare all functions, or define it to some empty > >thing, or #ifdeffery if you have to. There are many options, it is > >not hard, and if it means you have to pull code further apart that is > >not so bad: you get cleaner, clearer code. > > Ok, if I understand well, your comment applies to the following indeed, > so you confirm the #ifdef is necessary.
As I said, not necessary, but it might be the easiest or even the cleanest here. Something for you and the maintainers to fight about, I'll stay out of it :-)
> However, my question was related to another part of the current > patchset, where the functions are always refined: > > > On PPC32 we set: > > +#define SLICE_LOW_SHIFT 28 > +#define SLICE_HIGH_SHIFT 0 > > On PPC64 we set: > > #define SLICE_LOW_SHIFT 28 > #define SLICE_HIGH_SHIFT 40 > > We define: > > +#define slice_bitmap_zero(dst, nbits) \ > + do { if (nbits) bitmap_zero(dst, nbits); } while (0) > > > We have a function with: > { > slice_bitmap_zero(ret->low_slices, SLICE_NUM_LOW); > slice_bitmap_zero(ret->high_slices, SLICE_NUM_HIGH); > }
SLICE_NUM_xx is not the same as SLICE_xx_SHIFT; I don't see how any of those shift values give nbits == 0.
> So the question is to find the better approach. Is the above approach > correct, including performance wise ?
If slice_bitmap_zero is inlined (or partially inlined) it is fine. Is it?
Segher
| |