Re: [PATCH v5 07/12] x86: remove the syscall_64 fast-path

From: Ingo Molnar
Date: Sun Jan 28 2018 - 04:29:26 EST



* Dan Williams <dan.j.williams@xxxxxxxxx> wrote:

> Quoting Linus:
>
> "Honestly, I'd rather get rid of the fast-path entirely. Compared to
> all the PTI mess, it's not even noticeable.
>
> And if we ever get CPU's that have this all fixed, we can re-visit
> introducing the fastpath. But this is all very messy and it doesn't
> seem worth it right now.
>
> If we get rid of the fastpath, we can lay out the slow path slightly
> better, and get rid of some of those jump-overs. And we'd get rid of
> the ptregs hooks entirely.
>
> So we can try to make the "slow" path better while at it, but I
> really don't think it matters much now in the post-PTI era. Sadly."

Please fix the title to have the proper prefix and to reference the function that
is actually modified by the patch, i.e. something like:

s/ x86: remove the syscall_64 fast-path
/ x86/entry/64: Remove the entry_SYSCALL_64() fast-path

With the title fixed:

Reviewed-by: Ingo Molnar <mingo@xxxxxxxxxx>

Thanks,

Ingo