Re: [PATCH] fork: Use THREAD_SIZE_ORDER

[Geert Uytterhoeven]

Hi Arnd,

On Mon, Mar 11, 2024 at 2:48 PM Arnd Bergmann <arnd@xxxxxxxx> wrote:
> On Mon, Mar 11, 2024, at 14:44, Geert Uytterhoeven wrote:
> > Use the existing THREAD_SIZE_ORDER definition instead of calculating it
> > from THREAD_SIZE and PAGE_SIZE.
> >
> > Signed-off-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
> > ---
> >  kernel/fork.c | 8 ++++----
> >  1 file changed, 4 insertions(+), 4 deletions(-)
> >
> > diff --git a/kernel/fork.c b/kernel/fork.c
> > index 0d944e92a43ffa13..e79fdfe1f0bf4953 100644
> > --- a/kernel/fork.c
> > +++ b/kernel/fork.c
> > @@ -252,9 +252,9 @@ static int memcg_charge_kernel_stack(struct vm_struct *vm)
> >       int ret;
> >       int nr_charged = 0;
> >
> > -     BUG_ON(vm->nr_pages != THREAD_SIZE / PAGE_SIZE);
> > +     BUG_ON(vm->nr_pages != THREAD_SIZE_ORDER);
> >
>
> That doesn't look right, THREAD_SIZE_ORDER not the number of
> pages but the the log2 of it, right?
>
> I think you want '(1 << THREAD_SIZE_ORDER)', but at that point
> it doesn't actually look simpler than the existing code.

Thank you for pointing out my silly mistake.

/me hides in a brown paper bag, with a coffee machine.

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68korg

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