Re: [RFC PATCH v3 1/3] mm: Factor out the pagetable pages account into new helper function

Mike Rapoport
2022-06-30T14:29:29Z

On Thu, Jun 30, 2022 at 07:11:14PM +0800, Baolin Wang wrote:
> Factor out the pagetable pages account into new helper functions to avoid
> duplicated code. Meanwhile these helper functions also will be used to
> account pagetable pages which do not need split pagetale lock.
>
> Meanwhile convert to use mod_lruvec_page_state() in case of non-order-0
> page table allocation.

These are *very* rare. I think only parisc may have non-order-0 pmd and pud
tables.
With that, I'd suggest making use of compound_nr() build time opt-in.

> Signed-off-by: Baolin Wang <baolin.wang@linux.alibaba.com>
> ---
> include/linux/mm.h | 24 ++++++++++++++++--------
> 1 file changed, 16 insertions(+), 8 deletions(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index a2270e3..3be6d2c 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -2353,20 +2353,30 @@ static inline void pgtable_init(void)
> pgtable_cache_init();
> }
>
> +static inline void pgtable_page_inc(struct page *page)
> +{
> + __SetPageTable(page);
> + mod_lruvec_page_state(page, NR_PAGETABLE, compound_nr(page));
> +}
> +
> +static inline void pgtable_page_dec(struct page *page)
> +{
> + __ClearPageTable(page);
> + mod_lruvec_page_state(page, NR_PAGETABLE, -compound_nr(page));
> +}
> +
> static inline bool pgtable_pte_page_ctor(struct page *page)
> {
> if (!ptlock_init(page))
> return false;
> - __SetPageTable(page);
> - inc_lruvec_page_state(page, NR_PAGETABLE);
> + pgtable_page_inc(page);
> return true;
> }
>
> static inline void pgtable_pte_page_dtor(struct page *page)
> {
> ptlock_free(page);
> - __ClearPageTable(page);
> - dec_lruvec_page_state(page, NR_PAGETABLE);
> + pgtable_page_dec(page);
> }
>
> #define pte_offset_map_lock(mm, pmd, address, ptlp) \
> @@ -2452,16 +2462,14 @@ static inline bool pgtable_pmd_page_ctor(struct page *page)
> {
> if (!pmd_ptlock_init(page))
> return false;
> - __SetPageTable(page);
> - inc_lruvec_page_state(page, NR_PAGETABLE);
> + pgtable_page_inc(page);
> return true;
> }
>
> static inline void pgtable_pmd_page_dtor(struct page *page)
> {
> pmd_ptlock_free(page);
> - __ClearPageTable(page);
> - dec_lruvec_page_state(page, NR_PAGETABLE);
> + pgtable_page_dec(page);
> }
>
> /*
> --
> 1.8.3.1
>

--
Sincerely yours,
Mike.