Re: [PATCH 2/3] mm: add mm_pxd_folded checks to pgtable_bytes accounting functions

From: Kirill A. Shutemov
Date: Wed Oct 31 2018 - 05:04:48 EST

On Mon, Oct 15, 2018 at 06:42:38PM +0200, Martin Schwidefsky wrote:
> The common mm code calls mm_dec_nr_pmds() and mm_dec_nr_puds()
> in free_pgtables() if the address range spans a full pud or pmd.
> If mm_dec_nr_puds/mm_dec_nr_pmds are non-empty due to configuration
> settings they blindly subtract the size of the pmd or pud table from
> pgtable_bytes even if the pud or pmd page table layer is folded.
> Add explicit mm_[pmd|pud]_folded checks to the four pgtable_bytes
> accounting functions mm_inc_nr_puds, mm_inc_nr_pmds, mm_dec_nr_puds
> and mm_dec_nr_pmds. As the check for folded page tables can be
> overwritten by the architecture, this allows to keep a correct
> pgtable_bytes value for platforms that use a dynamic number of
> page table levels.
> Signed-off-by: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>

Looks fine to me.

Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>

Kirill A. Shutemov