Re: [patch] mm: memcg: update the correct soft limit tree duringmigration

[Kirill A. Shutemov]

On Fri, Jan 13, 2012 at 04:41:31PM +0100, Johannes Weiner wrote:
> end_migration() passes the old page instead of the new page to commit
> the charge.  This page descriptor is not used for committing itself,
> though, since we also pass the (correct) page_cgroup descriptor.  But
> it's used to find the soft limit tree through the page's zone, so the
> soft limit tree of the old page's zone is updated instead of that of
> the new page's, which might get slightly out of date until the next
> charge reaches the ratelimit point.
> 
> This glitch has been present since '5564e88 memcg: condense
> page_cgroup-to-page lookup points'.
> 
> Reported-by: Hugh Dickins <hughd@xxxxxxxxxx>
> Signed-off-by: Johannes Weiner <hannes@xxxxxxxxxxx>

Acked-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>


-- 
 Kirill A. Shutemov
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