Re: [PATCH 08/16] sched: Reschedule task on preferred NUMA node once selected

Mel Gorman
2013-07-12T10:28:26Z

On Fri, Jul 12, 2013 at 12:14:08PM +0200, Peter Zijlstra wrote:
> On Thu, Jul 11, 2013 at 03:09:14PM +0100, Mel Gorman wrote:
> > That might be necessary when the machine is overloaded. As a
> > starting point the following should retry the migrate a number of times
> > until success. The retry is checked on every fault but should not fire
> > more than once every 100ms.
>
> Yeah, something like that might work. But getting a working imbalance bound is
> important. The current very weak direct migration is the only thing that keeps
> the system from massively skewing load.

I've corrected a flaw in that proposed patch, pulled in the check for
dst load vs src load, and am adding another patch that will fallback to
less preferred nodes if task_numa_find_cpu fails to find a suitable CPU.

--
Mel Gorman
SUSE Labs