Messages in this thread Patch in this message | | | From | Kairui Song <> | Subject | [PATCH v2 2/4] swap: avoid a redundant pte map if ra window is 1 | Date | Tue, 20 Dec 2022 02:58:38 +0800 |
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From: Kairui Song <kasong@tencent.com>
Avoid a redundant pte map/unmap when swap readahead window is 1.
Signed-off-by: Kairui Song <kasong@tencent.com> Reviewed-by: "Huang, Ying" <ying.huang@intel.com> --- 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 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) -- 2.35.2
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