Re: [PATCH] x86/retpoline/entry: Disable the entire SYSCALL64 fast path with retpolines on

[Linus Torvalds]

On Thu, Jan 25, 2018 at 1:08 PM, Andy Lutomirski <luto@xxxxxxxxxx> wrote:
>
> With retpoline, the retpoline in the trampoline sucks.  I don't need
> perf for that -- I've benchmarked it both ways.  It sucks.  I'll fix
> it, but it'll be kind of complicated.

Ahh, I'd forgotten about that (and obviously didn't see it in the profiles).

But yeah, that is fixable even if it does require a page per CPU. Or
did you have some clever scheme in mind?

But that's independent of the slow/fast path.

          Linus