Re: [PATCH] mm/vma: Append unlikely() while testing VMA access permissions

[Geert Uytterhoeven]

Hi Anshuman,

Thanks for your patch!

On Mon, Feb 24, 2020 at 7:22 AM Anshuman Khandual
<anshuman.khandual@xxxxxxx> wrote:
> It is unlikely that an inaccessible VMA without required permission flags
> will get a page fault. Hence lets just append unlikely() directive to such

Why? Isn't it the idea that you get a page fault when the page is not
accessible?

> checks in order to improve performance while also standardizing it across
> various platforms.

Does it make a difference to add these? Have you benchmarked this?
https://lwn.net/Articles/420019/

Gr{oetje,eeting}s,

                        Geert


--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@xxxxxxxxxxxxxx

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds