Re: [PATCH 07/63] mm: numa: Sanitize task_numa_fault() callsites

[Rik van Riel]

On 10/07/2013 06:28 AM, Mel Gorman wrote:
> There are three callers of task_numa_fault():
> 
>  - do_huge_pmd_numa_page():
>      Accounts against the current node, not the node where the
>      page resides, unless we migrated, in which case it accounts
>      against the node we migrated to.
> 
>  - do_numa_page():
>      Accounts against the current node, not the node where the
>      page resides, unless we migrated, in which case it accounts
>      against the node we migrated to.
> 
>  - do_pmd_numa_page():
>      Accounts not at all when the page isn't migrated, otherwise
>      accounts against the node we migrated towards.
> 
> This seems wrong to me; all three sites should have the same
> sementaics, furthermore we should accounts against where the page
> really is, we already know where the task is.
> 
> So modify all three sites to always account; we did after all receive
> the fault; and always account to where the page is after migration,
> regardless of success.
> 
> They all still differ on when they clear the PTE/PMD; ideally that
> would get sorted too.
> 
> Cc: stable <stable@xxxxxxxxxxxxxxx>
> Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Signed-off-by: Mel Gorman <mgorman@xxxxxxx>

Reviewed-by: Rik van Riel <riel@xxxxxxxxxx>

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