| Date | Thu, 1 Aug 2013 16:46:04 +0100 | From | Mel Gorman <> | Subject | Re: [PATCH 17/18] sched: Retry migration of tasks to CPU on a preferred node |
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On Thu, Aug 01, 2013 at 10:43:27AM +0530, Srikar Dronamraju wrote: > * Mel Gorman <mgorman@suse.de> [2013-07-15 16:20:19]: > > > When a preferred node is selected for a tasks there is an attempt to migrate > > the task to a CPU there. This may fail in which case the task will only > > migrate if the active load balancer takes action. This may never happen if > > Apart from load imbalance or heavily loaded cpus on the preferred node, > what could be the other reasons for migration failure with > migrate_task_to()?
These were the reasons I expected that migration might fail.
> I see it almost similar to active load balance except > for pushing instead of pulling tasks. > > If load imbalance is the only reason, do we need to retry? If the task > is really so attached to memory on that node, shouldn't we getting > task_numa_placement hit before the next 5 seconds? >
Depends on the PTE scanning rate.
-- Mel Gorman SUSE Labs
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