Re: [PATCH v2 05/16] mm/huge_memory: use helper touch_pmd in huge_pmd_set_accessed

From: Muchun Song
Date: Tue Jun 28 2022 - 11:01:43 EST


On Tue, Jun 28, 2022 at 09:28:24PM +0800, Miaohe Lin wrote:
> Use helper touch_pmd to set pmd accessed to simplify the code and improve
> the readability. No functional change intended.
>
> Signed-off-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>
> ---
> mm/huge_memory.c | 18 +++++-------------
> 1 file changed, 5 insertions(+), 13 deletions(-)
>
> diff --git a/mm/huge_memory.c b/mm/huge_memory.c
> index d55d5efa06c8..d9fe9b034783 100644
> --- a/mm/huge_memory.c
> +++ b/mm/huge_memory.c
> @@ -1120,15 +1120,15 @@ EXPORT_SYMBOL_GPL(vmf_insert_pfn_pud_prot);
> #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */
>
> static void touch_pmd(struct vm_area_struct *vma, unsigned long addr,
> - pmd_t *pmd, int flags)
> + pmd_t *pmd, bool write)

The same as comments as mentioned in previous thread. E.g. follow_devmap_pmd()
and follow_trans_huge_pmd().

Thanks.

> {
> pmd_t _pmd;
>
> _pmd = pmd_mkyoung(*pmd);
> - if (flags & FOLL_WRITE)
> + if (write)
> _pmd = pmd_mkdirty(_pmd);
> if (pmdp_set_access_flags(vma, addr & HPAGE_PMD_MASK,
> - pmd, _pmd, flags & FOLL_WRITE))
> + pmd, _pmd, write))
> update_mmu_cache_pmd(vma, addr, pmd);
> }
>
> @@ -1398,21 +1398,13 @@ void huge_pud_set_accessed(struct vm_fault *vmf, pud_t orig_pud)
>
> void huge_pmd_set_accessed(struct vm_fault *vmf)
> {
> - pmd_t entry;
> - unsigned long haddr;
> bool write = vmf->flags & FAULT_FLAG_WRITE;
> - pmd_t orig_pmd = vmf->orig_pmd;
>
> vmf->ptl = pmd_lock(vmf->vma->vm_mm, vmf->pmd);
> - if (unlikely(!pmd_same(*vmf->pmd, orig_pmd)))
> + if (unlikely(!pmd_same(*vmf->pmd, vmf->orig_pmd)))
> goto unlock;
>
> - entry = pmd_mkyoung(orig_pmd);
> - if (write)
> - entry = pmd_mkdirty(entry);
> - haddr = vmf->address & HPAGE_PMD_MASK;
> - if (pmdp_set_access_flags(vmf->vma, haddr, vmf->pmd, entry, write))
> - update_mmu_cache_pmd(vmf->vma, vmf->address, vmf->pmd);
> + touch_pmd(vmf->vma, vmf->address, vmf->pmd, write);
>
> unlock:
> spin_unlock(vmf->ptl);
> --
> 2.23.0
>
>