Re: [GIT PULL] x86/mm changes for v5.9

From: Ingo Molnar
Date: Thu Aug 06 2020 - 17:21:59 EST



* Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:

> On Thu, Aug 6, 2020 at 11:57 AM Joerg Roedel <jroedel@xxxxxxx> wrote:
> >
> > On Thu, Aug 06, 2020 at 03:10:34PM +0200, Ingo Molnar wrote:
> > >
> > > * Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote:
> > > > So apparently the "the page-table pages are all pre-allocated now" is
> > > > simply not true. Joerg?
> >
> > It pre-allocates the whole vmalloc/ioremap PUD/P4D pages, but I actually
> > only tested it with 4-level paging, as I don't have access to 5-level
> > paging hardware.
>
> I don't think Jason has either.
>
> The
>
> PGD 0 P4D 0
>
> line tells us that "pgd_present()" is true, even though PGD is 0
> (otherwise it wouldn't print the P4D part). That means that he doesn't
> have l5 enabled.
>
> But you may obviously have different settings for CONFIG_X86_5LEVEL,
> and maybe that ends up changing something?
>
> But since apparently it's not immediately obvious what the problem is,
> I'll revert it for now.

I've reverted it in x86/urgent as well earlier today, can send you
that tree right now if you prefer that route.

Thanks,

Ingo