Messages in this thread | | | Subject | Re: [PATCH v2 1/9] mm: introduce pmd_install() helper | From | Qi Zheng <> | Date | Thu, 26 Aug 2021 00:20:31 +0800 |
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On 2021/8/25 AM12:26, David Hildenbrand wrote: > On 19.08.21 05:18, Qi Zheng wrote: >> Currently we have three times the same few lines repeated in the >> code. Deduplicate them by newly introduced pmd_install() helper. >> >> Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com> >> --- >> include/linux/mm.h | 1 + >> mm/filemap.c | 11 ++--------- >> mm/memory.c | 34 ++++++++++++++++------------------ >> 3 files changed, 19 insertions(+), 27 deletions(-) >> >> diff --git a/include/linux/mm.h b/include/linux/mm.h >> index ce8fc0fd6d6e..57e48217bd71 100644 >> --- a/include/linux/mm.h >> +++ b/include/linux/mm.h >> @@ -2471,6 +2471,7 @@ static inline spinlock_t *pud_lock(struct >> mm_struct *mm, pud_t *pud) >> return ptl; >> } >> +extern void pmd_install(struct mm_struct *mm, pmd_t *pmd, pgtable_t >> *pte); >> extern void __init pagecache_init(void); >> extern void __init free_area_init_memoryless_node(int nid); >> extern void free_initmem(void); >> diff --git a/mm/filemap.c b/mm/filemap.c >> index 53913fced7ae..9f773059c6dc 100644 >> --- a/mm/filemap.c >> +++ b/mm/filemap.c >> @@ -3210,15 +3210,8 @@ static bool filemap_map_pmd(struct vm_fault >> *vmf, struct page *page) >> } >> } >> - 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)) { >> diff --git a/mm/memory.c b/mm/memory.c >> index 39e7a1495c3c..ef7b1762e996 100644 >> --- a/mm/memory.c >> +++ b/mm/memory.c >> @@ -433,9 +433,20 @@ void free_pgtables(struct mmu_gather *tlb, struct >> vm_area_struct *vma, >> } >> } >> +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; >> @@ -455,13 +466,7 @@ int __pte_alloc(struct mm_struct *mm, pmd_t *pmd) >> */ >> 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; >> @@ -4027,17 +4032,10 @@ vm_fault_t finish_fault(struct vm_fault *vmf) >> 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() */ >> > > Reviewed-by: David Hildenbrand <david@redhat.com>
Thanks for your review, I will add this to the patch v3.
> > That's mostly unrelated to the remaining part of the series and can be > picked up early.
The implementation of subsequent patches depends on pmd_install(). So I am worried that if this patch is submitted as a separate patch, subsequent patches will not be updated until this patch is merged. What do you think?
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