Currently we have three times the same few lines repeated in the
code. Deduplicate them by newly introduced pte_install() helper.
Signed-off-by: Qi Zheng <[email protected]>
---
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 57453dba41b9..5efd63a20d72 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2374,6 +2374,7 @@ static inline spinlock_t *pud_lock(struct mm_struct *mm, pud_t *pud)
return ptl;
}
+extern void pte_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 7b365fdef7a5..4955641f2cf0 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -3173,15 +3173,8 @@ 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))
+ pte_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 94a17a9a48ab..a0ac4b33e07a 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 pte_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);
+ pte_install(mm, pmd, &new);
if (new)
pte_free(mm, new);
return 0;
@@ -4026,17 +4031,10 @@ 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)
+ pte_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() */
--
2.11.0
On Sun, Jul 18, 2021 at 12:30:28PM +0800, Qi Zheng wrote:
> Currently we have three times the same few lines repeated in the
> code. Deduplicate them by newly introduced pte_install() helper.
>
> Signed-off-by: Qi Zheng <[email protected]>
I don't like the name of the helper: we have confusion of PTE being
PTE-entry or PTE page table. And pte_install() doing pmd_populate()
doesn't help the situation.
Maybe pmd_install()? Or pte_table_install()? I donno.
--
Kirill A. Shutemov
On 7/19/21 5:31 AM, Kirill A. Shutemov wrote:
> On Sun, Jul 18, 2021 at 12:30:28PM +0800, Qi Zheng wrote:
>> Currently we have three times the same few lines repeated in the
>> code. Deduplicate them by newly introduced pte_install() helper.
>>
>> Signed-off-by: Qi Zheng <[email protected]>
>
> I don't like the name of the helper: we have confusion of PTE being
> PTE-entry or PTE page table. And pte_install() doing pmd_populate()
> doesn't help the situation.
>
> Maybe pmd_install()? Or pte_table_install()? I donno.
>
Look good to me, I will use pmd_install().