On Tue, Feb 13, 2018 at 03:00:20PM +0000, Mel Gorman wrote: > On Tue, Feb 13, 2018 at 03:43:26PM +0100, Peter Zijlstra wrote: > > > > > > Well, it was deliberate. While it's possible to be on the same memory > > > node and not sharing cache, the scheduler typically is more concerned with > > > the LLC than NUMA per-se. If they share LLC, then I also assume that they > > > share memory locality. > > > > True, but the remaining code only has effect for numa balance, which is > > concerned with nodes. So I don't see the point of using something > > potentially smaller. > > > > Suppose someone did hardware where a node has 2 cache clusters, then > > we'd still set a wake_affine back-off for numa-balance, even though it > > remains on the same node. > > > > How would that be useful? > > Fair point, it could be unexpected from a NUMA balancing perspective and > sub-numa clustering does exist so it's a potential issue. I'm happy to > change it to cpu_to_node. I can resend the series if you prefer but feel > free to change it in-place if you're picking it up. I do not expect any > change on the machines I tested with as for all of them LLC was equivalent > to checking the node ID.
OK, changed it locally. Thanks!
