Hi Peter,
On Wed, Aug 06, 2014 at 01:30:40PM -0400, Peter Feiner wrote:
> On Fri, Aug 01, 2014 at 03:20:42PM -0400, Naoya Horiguchi wrote:
> > Page table walker has the information of the current vma in mm_walk, so
> > we don't have to call find_vma() in each pagemap_hugetlb_range() call.
>
> You could also get rid of a bunch of code in pagemap_pte_range:
Thanks for the comment.
> ---
> fs/proc/task_mmu.c | 33 ++++++---------------------------
> 1 file changed, 6 insertions(+), 27 deletions(-)
>
> diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
> index 9b30bdd..e9af130 100644
> --- a/fs/proc/task_mmu.c
> +++ b/fs/proc/task_mmu.c
> @@ -1035,16 +1035,14 @@ static inline void thp_pmd_to_pagemap_entry(pagemap_entry_t *pme, struct pagemap
> static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
> struct mm_walk *walk)
> {
> - struct vm_area_struct *vma;
> + struct vm_area_struct *vma = walk->vma
> struct pagemapread *pm = walk->private;
> spinlock_t *ptl;
> pte_t *pte;
> int err = 0;
> - pagemap_entry_t pme = make_pme(PM_NOT_PRESENT(pm->v2));
> + pagemap_entry_t pme;
>
> - /* find the first VMA at or above 'addr' */
> - vma = find_vma(walk->mm, addr);
> - if (vma && pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
> + if (pmd_trans_huge_lock(pmd, vma, &ptl) == 1) {
> int pmd_flags2;
>
> if ((vma->vm_flags & VM_SOFTDIRTY) || pmd_soft_dirty(*pmd))
> @@ -1069,28 +1067,9 @@ static int pagemap_pte_range(pmd_t *pmd, unsigned long addr, unsigned long end,
> if (pmd_trans_unstable(pmd))
> return 0;
> for (; addr != end; addr += PAGE_SIZE) {
> - int flags2;
> -
> - /* check to see if we've left 'vma' behind
> - * and need a new, higher one */
> - if (vma && (addr >= vma->vm_end)) {
> - vma = find_vma(walk->mm, addr);
> - if (vma && (vma->vm_flags & VM_SOFTDIRTY))
> - flags2 = __PM_SOFT_DIRTY;
> - else
> - flags2 = 0;
> - pme = make_pme(PM_NOT_PRESENT(pm->v2) | PM_STATUS2(pm->v2, flags2));
> - }
Right. Soft dirty check is done in pte_to_pagemap_entry(), and vma
boundary check is done in mm/pagewalk.c, so we don't need this block
any more.
Thanks,
Naoya Horiguchi
> -
> - /* check that 'vma' actually covers this address,
> - * and that it isn't a huge page vma */
> - if (vma && (vma->vm_start <= addr) &&
> - !is_vm_hugetlb_page(vma)) {
> - pte = pte_offset_map(pmd, addr);
> - pte_to_pagemap_entry(&pme, pm, vma, addr, *pte);
> - /* unmap before userspace copy */
> - pte_unmap(pte);
> - }
> + pte = pte_offset_map(pmd, addr);
> + pte_to_pagemap_entry(&pme, pm, vma, addr, *pte);
> + pte_unmap(pte);
> err = add_to_pagemap(addr, &pme, pm);
> if (err)
> return err;
> --
> 2.0.0.526.g5318336
>
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