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From:   Ard Biesheuvel <ardb@kernel.org>
Date:   Tue, 19 Apr 2022 20:29:27 +0200
Message-ID: <CAMj1kXFnEhJ4Qu50Ads9psY6kmT3ddw5Za+6-YqUM+eYj1Oafw@mail.gmail.com>
Subject: Re: [PATCH v2 7/9] mm: Calc the right pfn if page size is not 4K
To:     Anshuman Khandual <anshuman.khandual@arm.com>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     Wupeng Ma <mawupeng1@huawei.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        Will Deacon <will@kernel.org>,
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On Tue, 19 Apr 2022 at 13:13, Anshuman Khandual
<anshuman.khandual@arm.com> wrote:
>
>
>
> On 4/14/22 15:43, Wupeng Ma wrote:
> > From: Ma Wupeng <mawupeng1@huawei.com>
> >
> > Previous 0x100000 is used to check the 4G limit in
> > find_zone_movable_pfns_for_nodes(). This is right in x86 because
> > the page size can only be 4K. But 16K and 64K are available in
> > arm64. So replace it with PHYS_PFN(SZ_4G).
> >
> > Signed-off-by: Ma Wupeng <mawupeng1@huawei.com>
> > ---
> >  mm/page_alloc.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> > index 6e5b4488a0c5..570d0ebf98df 100644
> > --- a/mm/page_alloc.c
> > +++ b/mm/page_alloc.c
> > @@ -7870,7 +7870,7 @@ static void __init find_zone_movable_pfns_for_nodes(void)
> >
> >                       usable_startpfn = memblock_region_memory_base_pfn(r);
> >
> > -                     if (usable_startpfn < 0x100000) {
> > +                     if (usable_startpfn < PHYS_PFN(SZ_4G)) {
> >                               mem_below_4gb_not_mirrored = true;
> >                               continue;
> >                       }
>
> Regardless PFN value should never be encoded directly.
>
> Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>

Acked-by: Ard Biesheuvel <ardb@kernel.org>

Andrew, can you please take this one through the -mm tree? The rest of
the series needs a bit more work, but is an obvious fix and there is
no point in holding it up.

Thanks,
Ard.