Re: [PATCH 1/2] futex: mark futex_detect_cmpxchg() as 'noinline'

[Guo Ren]

Hi Arnd,

On Tue, Dec 15, 2020 at 7:26 PM Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
>
> On Tue, Dec 15, 2020 at 7:09 AM Guo Ren <guoren@xxxxxxxxxx> wrote:
> > On Mon, Dec 14, 2020 at 9:15 PM Arnd Bergmann <arnd@xxxxxxxxxx> wrote:
> > > I had a look at what other architectures always implement
> > > futex_atomic_cmpxchg_inatomic() or can use the asm-generic non-SMP version,
> > > and I found that it's pretty much all of them, the odd ones being just sparc32
> > > and csky, which use asm-generic/futex.h but do have an SMP option,
> > > as well as xtensa
> > >
> > > I would guess that for csky, this is a mistake, as the architecture is fairly
> > > new and should be able to implement it. Not sure about sparc32.
> >
> > The c610, c807, c810 don't support SMP, so futex_cmpxchg_enabled = 1
> > with asm-generic's implementation.
> > For c860, there is no HAVE_FUTEX_CMPXCHG and cmpxchg_inatomic/inuser
> > implementation, so futex_cmpxchg_enabled = 0.
> >
> > Thx for point it out, we'll implement cmpxchg_inatomic/inuser for C860
> > and still use asm-generic for non-smp CPUs.
>
> Sounds good to me.
Done: https://lore.kernel.org/linux-csky/1608478763-60148-3-git-send-email-guoren@xxxxxxxxxx/T/#u

-- 
Best Regards
 Guo Ren

ML: https://lore.kernel.org/linux-csky/