On Thu, 1 Mar 2012 17:32:54 +0800
Bob Liu <lliubbo@xxxxxxxxx> wrote:
> +static int ksm_check_mm(struct mm_struct *mm, struct vm_area_struct *vma,
> + unsigned long addr)
> +{
> + if (ksm_test_exit(mm))
> + return 0;
> + vma = find_vma(mm, addr);
> + if (!vma || vma->vm_start > addr)
> + return 0;
> + if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma)
> + return 0;
> + return 1;
> +}
Can we please think of a suitable name for this check, other than
"check"? IOW, give the function a meaningful name which describes what
it is checking?
And it's not checking the mm, is it? It is checking the address: to
see whether it lies within a mergeable anon vma.
So maybe
--- a/mm/ksm.c~ksm-cleanup-introduce-ksm_check_mm-fix
+++ a/mm/ksm.c
@@ -375,17 +375,17 @@ static int break_ksm(struct vm_area_stru
return (ret & VM_FAULT_OOM) ? -ENOMEM : 0;
}
-static int ksm_check_mm(struct mm_struct *mm, struct vm_area_struct *vma,
- unsigned long addr)
+static bool in_mergeable_anon_vma(struct mm_struct *mm,
+ struct vm_area_struct *vma, unsigned long addr)
{
if (ksm_test_exit(mm))
- return 0;
+ return false;
vma = find_vma(mm, addr);
if (!vma || vma->vm_start > addr)
- return 0;
+ return false;
if (!(vma->vm_flags & VM_MERGEABLE) || !vma->anon_vma)
- return 0;
- return 1;
+ return false;
+ return true;
}
static void break_cow(struct rmap_item *rmap_item)
@@ -401,7 +401,7 @@ static void break_cow(struct rmap_item *
put_anon_vma(rmap_item->anon_vma);
down_read(&mm->mmap_sem);
- if (ksm_check_mm(mm, vma, addr))
+ if (in_mergeable_anon_vma(mm, vma, addr))
break_ksm(vma, addr);
up_read(&mm->mmap_sem);
}
@@ -428,7 +428,7 @@ static struct page *get_mergeable_page(s
struct page *page;
down_read(&mm->mmap_sem);
- if (!ksm_check_mm(mm, vma, addr))
+ if (!in_mergeable_anon_vma(mm, vma, addr))
goto out;
page = follow_page(vma, addr, FOLL_GET);
_
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