Re: [PATCH 1/9] mm/huge_memory: Use zap_deposited_table() more

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

Oliver O'Halloran <oohall@gmail.com> writes:

> Depending flags of the PMD being zapped there may or may not be a
> deposited pgtable to be freed. In two of the three cases this is open
> coded while the third uses the zap_deposited_table() helper. This patch
> converts the others to use the helper to clean things up a bit.
>
> Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>
> Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
> Cc: linux-mm@kvack.org
> Signed-off-by: Oliver O'Halloran <oohall@gmail.com>

Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>

> ---
> For reference:
>
> void zap_deposited_table(struct mm_struct *mm, pmd_t *pmd)
> {
>         pgtable_t pgtable;
>
>         pgtable = pgtable_trans_huge_withdraw(mm, pmd);
>         pte_free(mm, pgtable);
>         atomic_long_dec(&mm->nr_ptes);
> }
> ---
>  mm/huge_memory.c | 8 ++------
>  1 file changed, 2 insertions(+), 6 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index b787c4cfda0e..aa01dd47cc65 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -1615,8 +1615,7 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
>  		if (is_huge_zero_pmd(orig_pmd))
>  			tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE);
>  	} else if (is_huge_zero_pmd(orig_pmd)) {
> -		pte_free(tlb->mm, pgtable_trans_huge_withdraw(tlb->mm, pmd));
> -		atomic_long_dec(&tlb->mm->nr_ptes);
> +		zap_deposited_table(tlb->mm, pmd);
>  		spin_unlock(ptl);
>  		tlb_remove_page_size(tlb, pmd_page(orig_pmd), HPAGE_PMD_SIZE);
>  	} else {
> @@ -1625,10 +1624,7 @@ int zap_huge_pmd(struct mmu_gather *tlb, struct vm_area_struct *vma,
>  		VM_BUG_ON_PAGE(page_mapcount(page) < 0, page);
>  		VM_BUG_ON_PAGE(!PageHead(page), page);
>  		if (PageAnon(page)) {
> -			pgtable_t pgtable;
> -			pgtable = pgtable_trans_huge_withdraw(tlb->mm, pmd);
> -			pte_free(tlb->mm, pgtable);
> -			atomic_long_dec(&tlb->mm->nr_ptes);
> +			zap_deposited_table(tlb->mm, pmd);
>  			add_mm_counter(tlb->mm, MM_ANONPAGES, -HPAGE_PMD_NR);
>  		} else {
>  			if (arch_needs_pgtable_deposit())
> -- 
> 2.9.3

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