Re: [PATCH 09/19] sched/numa: Modify migrate_swap to accept additional params

From: Rik van Riel
Date: Mon Jun 04 2018 - 13:00:28 EST


On Mon, 2018-06-04 at 15:30 +0530, Srikar Dronamraju wrote:
> There are checks in migrate_swap_stop that check if the task/cpu
> combination is as per migrate_swap_arg before migrating.
>
> However atleast one of the two tasks to be swapped by migrate_swap
> could
> have migrated to a completely different cpu before updating the
> migrate_swap_arg. The new cpu where the task is currently running
> could
> be a different node too. If the task has migrated, numa balancer
> might
> end up placing a task in a wrong node. Instead of achieving node
> consolidation, it may end up spreading the load across nodes.
>
> To avoid that pass the cpus as additional parameters.
>
> While here, place migrate_swap under CONFIG_NUMA_BALANCING.
>
> Signed-off-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>

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

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