diff options
| author | Kairui Song <kasong@tencent.com> | 2022-12-19 19:58:38 +0100 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-01-19 02:12:45 +0100 |
| commit | 18ad72f5b7186336646182b17e0654bf907b39e6 (patch) | |
| tree | c40e316a0f982f865b48a4413b544090a2fbc8da /mm/swap_state.c | |
| parent | swapfile: get rid of volatile and avoid redundant read (diff) | |
| download | linux-18ad72f5b7186336646182b17e0654bf907b39e6.tar.xz linux-18ad72f5b7186336646182b17e0654bf907b39e6.zip | |
swap: avoid a redundant pte map if ra window is 1
Avoid a redundant pte map/unmap when swap readahead window is 1.
Link: https://lkml.kernel.org/r/20221219185840.25441-3-ryncsn@gmail.com
Signed-off-by: Kairui Song <kasong@tencent.com>
Reviewed-by: "Huang, Ying" <ying.huang@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/swap_state.c')
| -rw-r--r-- | mm/swap_state.c | 7 |
1 files changed, 2 insertions, 5 deletions
diff --git a/mm/swap_state.c b/mm/swap_state.c index 2927507b43d8..af8bc123b7c4 100644 --- a/mm/swap_state.c +++ b/mm/swap_state.c @@ -727,8 +727,6 @@ 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)); @@ -739,12 +737,11 @@ 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) |