Re: [PATCH 22/63] sched: Favour moving tasks towards the preferrednode

[Rik van Riel]

On 10/07/2013 06:29 AM, Mel Gorman wrote:
> This patch favours moving tasks towards NUMA node that recorded a higher
> number of NUMA faults during active load balancing.  Ideally this is
> self-reinforcing as the longer the task runs on that node, the more faults
> it should incur causing task_numa_placement to keep the task running on that
> node. In reality a big weakness is that the nodes CPUs can be overloaded
> and it would be more efficient to queue tasks on an idle node and migrate
> to the new node. This would require additional smarts in the balancer so
> for now the balancer will simply prefer to place the task on the preferred
> node for a PTE scans which is controlled by the numa_balancing_settle_count
> sysctl. Once the settle_count number of scans has complete the schedule
> is free to place the task on an alternative node if the load is imbalanced.
> 
> [srikar@xxxxxxxxxxxxxxxxxx: Fixed statistics]
> [peterz@xxxxxxxxxxxxx: Tunable and use higher faults instead of preferred]
> Signed-off-by: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> Signed-off-by: Mel Gorman <mgorman@xxxxxxx>

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

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