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(-)
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)
--
2.35.2
