Messages in this thread | | | Date | Wed, 30 May 2012 14:17:29 -0500 (CDT) | From | Christoph Lameter <> | Subject | Re: [PATCH 1/6] Revert "mm: mempolicy: Let vma_merge and vma_split handle vma->vm_policy linkages" |
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On Wed, 30 May 2012, kosaki.motohiro@gmail.com wrote:
> From: KOSAKI Motohiro <kosaki.motohiro@gmail.com> > > commit 05f144a0d5 removed vma->vm_policy updates code and it is a purpose of > mbind_range(). Now, mbind_range() is virtually no-op. no-op function don't > makes any bugs, I agree. but maybe it is not right fix.
I dont really understand the changelog. But to restore the policy_vma() is the right thing to do since there are potential multiple use cases where we want to apply a policy to a vma.
Proposed new changelog:
Commit 05f144a0d5 folded policy_vma() into mbind_range(). There are other use cases of policy_vma(*) though and so revert a piece of that commit in order to have a policy_vma() function again.
> @@ -655,23 +676,9 @@ static int mbind_range(struct mm_struct *mm, unsigned long start, > if (err) > goto out; > } > - > - /* > - * Apply policy to a single VMA. The reference counting of > - * policy for vma_policy linkages has already been handled by > - * vma_merge and split_vma as necessary. If this is a shared > - * policy then ->set_policy will increment the reference count > - * for an sp node. > - */
You are dropping the nice comments by Mel that explain the refcounting.
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