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

Mel Gorman
2018-06-05T08:58:43Z

On Mon, Jun 04, 2018 at 03:30:18PM +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@linux.vnet.ibm.com>

Acked-by: Mel Gorman <mgorman@techsingularity.net>

--
Mel Gorman
SUSE Labs