Kairui Song <ryncsn@xxxxxxxxx> writes:
> From: Kairui Song <kasong@xxxxxxxxxxx>
>
> Avoid a redundant pte map/unmap when swap readahead window is 1.
>
> Signed-off-by: Kairui Song <kasong@xxxxxxxxxxx>
> ---
> mm/swap_state.c | 7 ++-----
> 1 file changed, 2 insertions(+), 5 deletions(-)
Good to reduce the line of code. Thanks!
Reviewed-by: "Huang, Ying" <ying.huang@xxxxxxxxx>
> diff --git a/mm/swap_state.c b/mm/swap_state.c
> index 438d0676c5be..60136bda78e3 100644
> --- a/mm/swap_state.c
> +++ b/mm/swap_state.c
> @@ -730,8 +730,6 @@ static void swap_ra_info(struct vm_fault *vmf,
> }
>
> faddr = vmf->address;
> - orig_pte = pte = pte_offset_map(vmf->pmd, faddr);
> -
> fpfn = PFN_DOWN(faddr);
> ra_val = GET_SWAP_RA_VAL(vma);
> pfn = PFN_DOWN(SWAP_RA_ADDR(ra_val));
> @@ -742,12 +740,11 @@ static void swap_ra_info(struct vm_fault *vmf,
> atomic_long_set(&vma->swap_readahead_info,
> SWAP_RA_VAL(faddr, win, 0));
>
> - if (win == 1) {
> - pte_unmap(orig_pte);
> + if (win == 1)
> return;
> - }
>
> /* Copy the PTEs because the page table may be unmapped */
> + orig_pte = pte = pte_offset_map(vmf->pmd, faddr);
> if (fpfn == pfn + 1)
> swap_ra_clamp_pfn(vma, faddr, fpfn, fpfn + win, &start, &end);
> else if (pfn == fpfn + 1)
