Re: [PATCH 01/11] mm,migration: Take a reference to the anon_vmabefore migrating

[KAMEZAWA Hiroyuki]

On Fri, 12 Mar 2010 16:41:17 +0000
Mel Gorman <mel@xxxxxxxxx> wrote:

> rmap_walk_anon() does not use page_lock_anon_vma() for looking up and
> locking an anon_vma and it does not appear to have sufficient locking to
> ensure the anon_vma does not disappear from under it.
> 
> This patch copies an approach used by KSM to take a reference on the
> anon_vma while pages are being migrated. This should prevent rmap_walk()
> running into nasty surprises later because anon_vma has been freed.
> 
> Signed-off-by: Mel Gorman <mel@xxxxxxxxx>
> Acked-by: Rik van Riel <riel@xxxxxxxxxx>
> ---
>  include/linux/rmap.h |   23 +++++++++++++++++++++++
>  mm/migrate.c         |   12 ++++++++++++
>  mm/rmap.c            |   10 +++++-----
>  3 files changed, 40 insertions(+), 5 deletions(-)
> 
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>

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