Re: [PATCH -mm] vmscan: report vm_flags in page_referenced()

[Minchan Kim]

On Tue, 12 May 2009 08:23:09 +0200
Peter Zijlstra <peterz@xxxxxxxxxxxxx> wrote:

> On Tue, 2009-05-12 at 10:51 +0800, Wu Fengguang wrote:
> > @@ -406,6 +408,7 @@ static int page_referenced_anon(struct p
> >                 if (mem_cont && !mm_match_cgroup(vma->vm_mm, mem_cont))
> >                         continue;
> >                 referenced += page_referenced_one(page, vma, &mapcount);
> > +               *vm_flags |= vma->vm_flags;
> >                 if (!mapcount)
> >                         break;
> >         }
> 
> Shouldn't that read:
> 
>   if (page_referenced_on(page, vma, &mapcount)) {
>     referenced++;
>     *vm_flags |= vma->vm_flags;
>   }
> 
> So that we only add the vma-flags of those vmas that actually have a
> young bit set?
> 
> In which case it'd be more at home in page_referenced_one():
> 
> @@ -381,6 +381,8 @@ out_unmap:
>  	(*mapcount)--;
>  	pte_unmap_unlock(pte, ptl);
>  out:
> +	if (referenced)
> +		*vm_flags |= vma->vm_flags;
>  	return referenced;
>  }

Good. I am ACK for peter's suggestion.
It can prevent setting vm_flag for worng vma which don't have the page.

-- 
Kinds Regards
Minchan Kim
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