Re: [PATCH 1/4] thp: clean up __collapse_huge_page_isolate

[Bob Liu <lliubbo@gmail.com>]

Sorry, should be to linux-mm instead of linux-kernel.
It's strange linux-mm not in the result by using
./scripts/get_maintainer.pl -f ./mm/huge_memory.c

On Thu, Oct 18, 2012 at 6:12 PM, Bob Liu <lliubbo@gmail.com> wrote:
> There are duplicated place using release_pte_pages().
> And release_all_pte_pages() can also be removed.
>
> Signed-off-by: Bob Liu <lliubbo@gmail.com>
> ---
>  mm/huge_memory.c |   37 +++++++++++--------------------------
>  1 file changed, 11 insertions(+), 26 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index a863af2..462d6ea 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -1700,64 +1700,49 @@ static void release_pte_pages(pte_t *pte, pte_t *_pte)
>         }
>  }
>
> -static void release_all_pte_pages(pte_t *pte)
> -{
> -       release_pte_pages(pte, pte + HPAGE_PMD_NR);
> -}
> -
>  static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
>                                         unsigned long address,
>                                         pte_t *pte)
>  {
>         struct page *page;
>         pte_t *_pte;
> -       int referenced = 0, isolated = 0, none = 0;
> +       int referenced = 0, isolated = 1, none = 0;
>         for (_pte = pte; _pte < pte+HPAGE_PMD_NR;
>              _pte++, address += PAGE_SIZE) {
>                 pte_t pteval = *_pte;
>                 if (pte_none(pteval)) {
>                         if (++none <= khugepaged_max_ptes_none)
>                                 continue;
> -                       else {
> -                               release_pte_pages(pte, _pte);
> +                       else
>                                 goto out;
> -                       }
>                 }
> -               if (!pte_present(pteval) || !pte_write(pteval)) {
> -                       release_pte_pages(pte, _pte);
> +               if (!pte_present(pteval) || !pte_write(pteval))
>                         goto out;
> -               }
>                 page = vm_normal_page(vma, address, pteval);
> -               if (unlikely(!page)) {
> -                       release_pte_pages(pte, _pte);
> +               if (unlikely(!page))
>                         goto out;
> -               }
> +
>                 VM_BUG_ON(PageCompound(page));
>                 BUG_ON(!PageAnon(page));
>                 VM_BUG_ON(!PageSwapBacked(page));
>
>                 /* cannot use mapcount: can't collapse if there's a gup pin */
> -               if (page_count(page) != 1) {
> -                       release_pte_pages(pte, _pte);
> +               if (page_count(page) != 1)
>                         goto out;
> -               }
>                 /*
>                  * We can do it before isolate_lru_page because the
>                  * page can't be freed from under us. NOTE: PG_lock
>                  * is needed to serialize against split_huge_page
>                  * when invoked from the VM.
>                  */
> -               if (!trylock_page(page)) {
> -                       release_pte_pages(pte, _pte);
> +               if (!trylock_page(page))
>                         goto out;
> -               }
>                 /*
>                  * Isolate the page to avoid collapsing an hugepage
>                  * currently in use by the VM.
>                  */
>                 if (isolate_lru_page(page)) {
>                         unlock_page(page);
> -                       release_pte_pages(pte, _pte);
>                         goto out;
>                 }
>                 /* 0 stands for page_is_file_cache(page) == false */
> @@ -1770,11 +1755,11 @@ static int __collapse_huge_page_isolate(struct vm_area_struct *vma,
>                     mmu_notifier_test_young(vma->vm_mm, address))
>                         referenced = 1;
>         }
> -       if (unlikely(!referenced))
> -               release_all_pte_pages(pte);
> -       else
> -               isolated = 1;
> +       if (unlikely(!referenced)) {
>  out:
> +               release_pte_pages(pte, _pte);
> +               isolated = 0;
> +       }
>         return isolated;
>  }
>
> --
> 1.7.9.5
>
>



-- 
Regards,
--Bob

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