Re: [PATCH v7 RESEND 5/6] arm64: futex: small optimisation for __llsc_futex_atomic_set()

Yeoreum Yun
2025-09-15T10:41:56Z

On Fri, Sep 12, 2025 at 05:36:20PM +0100, Catalin Marinas wrote:
> On Thu, Sep 11, 2025 at 05:19:11PM +0100, Yeoreum Yun wrote:
> > > > +static __always_inline int
> > > > +__llsc_futex_atomic_set(int oparg, u32 __user *uaddr, int *oval)
> [...]
> > > Hmm, I'm really not sure this is worthwhile. I doubt the "optimisation"
> > > actually does anything and adding a whole new block of asm just for the
> > > SET case isn't much of an improvement on the maintainability side, either.
> >
> > TBH, I had the same question, but I thought this code seems to modify
> > freqenetly, I decide even a small optimisation -- reduce one instruction
> > only.
> >
> > But I don't have strong opinion for this patch.
> > If it's not good for maintainability perspective,
> > This patch can be dropped.
>
> I'd drop it for now unless you can show some performance benefits
> (unlikely).

Yes. not much of improvement. So I'll drop this patch.
Thanks.

--
Sincerely,
Yeoreum Yun