From: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> Subject: mm: introduce pmd_install() helper Patch series "Do some code cleanups related to mm", v3. This patch (of 2): Currently we have three times the same few lines repeated in the code. Deduplicate them by newly introduced pmd_install() helper. Link: https://lkml.kernel.org/r/20210901102722.47686-1-zhengqi.arch@xxxxxxxxxxxxx Link: https://lkml.kernel.org/r/20210901102722.47686-2-zhengqi.arch@xxxxxxxxxxxxx Signed-off-by: Qi Zheng <zhengqi.arch@xxxxxxxxxxxxx> Reviewed-by: David Hildenbrand <david@xxxxxxxxxx> Reviewed-by: Muchun Song <songmuchun@xxxxxxxxxxxxx> Acked-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx> Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxxxx> Cc: Vladimir Davydov <vdavydov.dev@xxxxxxxxx> Cc: Mika Penttila <mika.penttila@xxxxxxxxxxxx> Cc: Vlastimil Babka <vbabka@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/filemap.c | 11 ++--------- mm/internal.h | 1 + mm/memory.c | 34 ++++++++++++++++------------------ 3 files changed, 19 insertions(+), 27 deletions(-) --- a/mm/filemap.c~mm-introduce-pmd_install-helper +++ a/mm/filemap.c @@ -3211,15 +3211,8 @@ static bool filemap_map_pmd(struct vm_fa } } - if (pmd_none(*vmf->pmd)) { - vmf->ptl = pmd_lock(mm, vmf->pmd); - if (likely(pmd_none(*vmf->pmd))) { - mm_inc_nr_ptes(mm); - pmd_populate(mm, vmf->pmd, vmf->prealloc_pte); - vmf->prealloc_pte = NULL; - } - spin_unlock(vmf->ptl); - } + if (pmd_none(*vmf->pmd)) + pmd_install(mm, vmf->pmd, &vmf->prealloc_pte); /* See comment in handle_pte_fault() */ if (pmd_devmap_trans_unstable(vmf->pmd)) { --- a/mm/internal.h~mm-introduce-pmd_install-helper +++ a/mm/internal.h @@ -38,6 +38,7 @@ vm_fault_t do_swap_page(struct vm_fault void free_pgtables(struct mmu_gather *tlb, struct vm_area_struct *start_vma, unsigned long floor, unsigned long ceiling); +void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte); static inline bool can_madv_lru_vma(struct vm_area_struct *vma) { --- a/mm/memory.c~mm-introduce-pmd_install-helper +++ a/mm/memory.c @@ -437,9 +437,20 @@ void free_pgtables(struct mmu_gather *tl } } +void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t *pte) +{ + spinlock_t *ptl = pmd_lock(mm, pmd); + + if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ + mm_inc_nr_ptes(mm); + pmd_populate(mm, pmd, *pte); + *pte = NULL; + } + spin_unlock(ptl); +} + int __pte_alloc(struct mm_struct *mm, pmd_t *pmd) { - spinlock_t *ptl; pgtable_t new = pte_alloc_one(mm); if (!new) return -ENOMEM; @@ -459,13 +470,7 @@ int __pte_alloc(struct mm_struct *mm, pm */ smp_wmb(); /* Could be smp_wmb__xxx(before|after)_spin_lock */ - ptl = pmd_lock(mm, pmd); - if (likely(pmd_none(*pmd))) { /* Has another populated it ? */ - mm_inc_nr_ptes(mm); - pmd_populate(mm, pmd, new); - new = NULL; - } - spin_unlock(ptl); + pmd_install(mm, pmd, &new); if (new) pte_free(mm, new); return 0; @@ -4028,17 +4033,10 @@ vm_fault_t finish_fault(struct vm_fault return ret; } - if (vmf->prealloc_pte) { - vmf->ptl = pmd_lock(vma->vm_mm, vmf->pmd); - if (likely(pmd_none(*vmf->pmd))) { - mm_inc_nr_ptes(vma->vm_mm); - pmd_populate(vma->vm_mm, vmf->pmd, vmf->prealloc_pte); - vmf->prealloc_pte = NULL; - } - spin_unlock(vmf->ptl); - } else if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd))) { + if (vmf->prealloc_pte) + pmd_install(vma->vm_mm, vmf->pmd, &vmf->prealloc_pte); + else if (unlikely(pte_alloc(vma->vm_mm, vmf->pmd))) return VM_FAULT_OOM; - } } /* See comment in handle_pte_fault() */ _
