linux-kernel - Re: [PATCHv2 1/2] mm: Introduce wrappers to access mm->nr

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Message-ID: <20171008125449.kgzjilgxzbropewj@node.shutemov.name>
Date:   Sun, 8 Oct 2017 15:54:49 +0300
From:   "Kirill A. Shutemov" <kirill@...temov.name>
To:     Dave Hansen <dave.hansen@...el.com>
Cc:     "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        Andrew Morton <akpm@...ux-foundation.org>, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, linux-api@...r.kernel.org,
        Michal Hocko <mhocko@...nel.org>
Subject: Re: [PATCHv2 1/2] mm: Introduce wrappers to access mm->nr_ptes

On Fri, Oct 06, 2017 at 04:10:31PM -0700, Dave Hansen wrote:
> On 10/05/2017 03:14 AM, Kirill A. Shutemov wrote:
> > +++ b/arch/sparc/mm/hugetlbpage.c
> > @@ -396,7 +396,7 @@ static void hugetlb_free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
> >  
> >  	pmd_clear(pmd);
> >  	pte_free_tlb(tlb, token, addr);
> > -	atomic_long_dec(&tlb->mm->nr_ptes);
> > +	mm_dec_nr_ptes(tlb->mm);
> >  }
> 
> If we're going to go replace all of these, I wonder if we should start
> doing it more generically.
> 
> 	mm_dec_nr_pgtable(PGTABLE_PTE, tlb->mm)
> 
> or even:
> 
> 	mm_dec_nr_pgtable(PGTABLE_LEVEL1, tlb->mm)
> 
> Instead of having a separate batch of functions for each level.

We don't have this kind of consolidation for any other page table related
helpers. Don't see a reason to start here.

This kind of changes can be part of overal page table privitives redesign
once/if we get there.

But feel free to send patches. :)

-- 
 Kirill A. Shutemov