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Message-ID: <CAMuHMdU-qdNMqwtpm+PMixKoicYHPokAQqWAh-Vw-sjZz_z7xA@mail.gmail.com>
Date: Fri, 17 Jun 2022 17:26:31 +0200
From: Geert Uytterhoeven <geert@...ux-m68k.org>
To: Peter Xu <peterx@...hat.com>
Cc: Mike Kravetz <mike.kravetz@...cle.com>,
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Subject: Re: [PATCH 1/4] hugetlb: skip to end of PT page mapping when pte not present
Hi Peter,
On Fri, Jun 17, 2022 at 4:22 PM Peter Xu <peterx@...hat.com> wrote:
> On Thu, Jun 16, 2022 at 02:05:15PM -0700, Mike Kravetz wrote:
> > @@ -6877,6 +6896,39 @@ pte_t *huge_pte_offset(struct mm_struct *mm,
> > return (pte_t *)pmd;
> > }
> >
> > +/*
> > + * Return a mask that can be used to update an address to the last huge
> > + * page in a page table page mapping size. Used to skip non-present
> > + * page table entries when linearly scanning address ranges. Architectures
> > + * with unique huge page to page table relationships can define their own
> > + * version of this routine.
> > + */
> > +unsigned long hugetlb_mask_last_page(struct hstate *h)
> > +{
> > + unsigned long hp_size = huge_page_size(h);
> > +
> > + switch (hp_size) {
> > + case P4D_SIZE:
> > + return PGDIR_SIZE - P4D_SIZE;
> > + case PUD_SIZE:
> > + return P4D_SIZE - PUD_SIZE;
> > + case PMD_SIZE:
> > + return PUD_SIZE - PMD_SIZE;
> > + default:
>
> Should we add a WARN_ON_ONCE() if it should never trigger?
And with panic_on_warn, it'll panic only once ;-)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org
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
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