Re: Linux 5.19-rc8

Yury Norov
2022-07-26T18:18:45Z

+ Geert Uytterhoeven <geert@linux-m68k.org>
+ linux-m68k@lists.linux-m68k.org

On Tue, Jul 26, 2022 at 10:51:01AM -0700, Linus Torvalds wrote:
> On Tue, Jul 26, 2022 at 10:39 AM Dennis Zhou <dennis@kernel.org> wrote:
> >
> > Are we okay with adding the contract find_*_bit() operations must handle
> > asking for past size properly? FWIW, we'd have to modify most of the
> > iterators in find.h.
>
> So I think we're ok with it, if only it makes the macros simpler.
>
> I also think we should probably look at the m68k case, because while
> that one seems to not have the bug that the arm case had, if we remove
> the arm case the m68k code is now the only non-generic case remaining.
>
> And it just makes me go "maybe we should get rid of the whole
> 'override the generic code' thing entirely?"
>
> I don't think that inlining the first word (like the m68k code does)
> is worth it, but it *is* possible that the architecture-specific
> functions generate better code for some common cases,

We have find_bit_benchmark to check how it works in practice. Would
be great if someone with access to the hardware can share numbers.

> so I think this
> is a "needs looking at the generated code" and not just a blind
> removal.
>
> Linus