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Subject[PATCH 2/2] mm: add the "struct mm_struct *mm" local into
Cosmetic, but expand_upwards() and expand_downwards() overuse
vma->vm_mm, a local variable makes sense imho.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
---
mm/mmap.c | 24 +++++++++++++-----------
1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/mm/mmap.c b/mm/mmap.c
index 4efdc37..7edf9ed 100644
--- a/mm/mmap.c
+++ b/mm/mmap.c
@@ -2148,6 +2148,7 @@ static int acct_stack_growth(struct vm_area_struct *vma, unsigned long size, uns
*/
int expand_upwards(struct vm_area_struct *vma, unsigned long address)
{
+ struct mm_struct *mm = vma->vm_mm;
int error;

if (!(vma->vm_flags & VM_GROWSUP))
@@ -2197,10 +2198,10 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
* So, we reuse mm->page_table_lock to guard
* against concurrent vma expansions.
*/
- spin_lock(&vma->vm_mm->page_table_lock);
+ spin_lock(&mm->page_table_lock);
if (vma->vm_flags & VM_LOCKED)
- vma->vm_mm->locked_vm += grow;
- vm_stat_account(vma->vm_mm, vma->vm_flags,
+ mm->locked_vm += grow;
+ vm_stat_account(mm, vma->vm_flags,
vma->vm_file, grow);
anon_vma_interval_tree_pre_update_vma(vma);
vma->vm_end = address;
@@ -2208,8 +2209,8 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
if (vma->vm_next)
vma_gap_update(vma->vm_next);
else
- vma->vm_mm->highest_vm_end = address;
- spin_unlock(&vma->vm_mm->page_table_lock);
+ mm->highest_vm_end = address;
+ spin_unlock(&mm->page_table_lock);

perf_event_mmap(vma);
}
@@ -2217,7 +2218,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
}
vma_unlock_anon_vma(vma);
khugepaged_enter_vma_merge(vma, vma->vm_flags);
- validate_mm(vma->vm_mm);
+ validate_mm(mm);
return error;
}
#endif /* CONFIG_STACK_GROWSUP || CONFIG_IA64 */
@@ -2228,6 +2229,7 @@ int expand_upwards(struct vm_area_struct *vma, unsigned long address)
int expand_downwards(struct vm_area_struct *vma,
unsigned long address)
{
+ struct mm_struct *mm = vma->vm_mm;
int error;

/*
@@ -2272,17 +2274,17 @@ int expand_downwards(struct vm_area_struct *vma,
* So, we reuse mm->page_table_lock to guard
* against concurrent vma expansions.
*/
- spin_lock(&vma->vm_mm->page_table_lock);
+ spin_lock(&mm->page_table_lock);
if (vma->vm_flags & VM_LOCKED)
- vma->vm_mm->locked_vm += grow;
- vm_stat_account(vma->vm_mm, vma->vm_flags,
+ mm->locked_vm += grow;
+ vm_stat_account(mm, vma->vm_flags,
vma->vm_file, grow);
anon_vma_interval_tree_pre_update_vma(vma);
vma->vm_start = address;
vma->vm_pgoff -= grow;
anon_vma_interval_tree_post_update_vma(vma);
vma_gap_update(vma);
- spin_unlock(&vma->vm_mm->page_table_lock);
+ spin_unlock(&mm->page_table_lock);

perf_event_mmap(vma);
}
@@ -2290,7 +2292,7 @@ int expand_downwards(struct vm_area_struct *vma,
}
vma_unlock_anon_vma(vma);
khugepaged_enter_vma_merge(vma, vma->vm_flags);
- validate_mm(vma->vm_mm);
+ validate_mm(mm);
return error;
}

--
2.4.3


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