Re: [PATCH 08/11] sched/numa: Bias swapping tasks based on their preferred node

From: Peter Zijlstra
Date: Thu Feb 13 2020 - 05:31:32 EST


On Wed, Feb 12, 2020 at 09:36:51AM +0000, Mel Gorman wrote:
> When swapping tasks for NUMA balancing, it is preferred that tasks move
> to or remain on their preferred node. When considering an imbalance,
> encourage tasks to move to their preferred node and discourage tasks from
> moving away from their preferred node.

Wasn't there an issue for workloads that span multiple nodes?

Say a 4 node system with 2 warehouses? Then each JVM will want 2 nodes,
instead of a single node, and strong preferred node stuff makes it
difficult to achieve this.

I forgot how we dealt with these cases, just something I worry about
when reading this.