On Mon, Jun 04, 2018 at 05:59:40AM -0700, Srikar Dronamraju wrote: > * Peter Zijlstra <pet...@infradead.org> [2018-06-04 14:23:36]: > > > OK, the above matches the description, but I'm puzzled by the remainder: > > > > > > > > - if (ng->active_nodes > 1 && numa_is_active_node(env.dst_nid, > > > ng)) > > > - sched_setnuma(p, env.dst_nid); > > > + if (nid != p->numa_preferred_nid) > > > + sched_setnuma(p, nid); > > > } > > > > That seems to entirely loose the active_node thing, or are you saying > > best_cpu already includes that? (Changelog could use a little help there > > I suppose) > > I think checking for active_nodes before calling sched_setnuma was a > mistake. > > Before this change, we may be retaining numa_preferred_nid to be the > source node while we select another node with better numa affinity to > run on. So we are creating a situation where we force a thread to run on > a node which is not going to be its preferred_node. So in the course of > regular load balancing, this task might then be moved to set > preferred_node which is actually not the preferred_node.
Then your Changelog had better explain all that, no?
