On Tue, Feb 12, 2019 at 08:49:03AM +0000, Jonathan Cameron wrote: > On Mon, 11 Feb 2019 08:23:04 -0700 > Keith Busch <keith.busch@xxxxxxxxx> wrote: > > > On Sun, Feb 10, 2019 at 09:19:58AM -0800, Jonathan Cameron wrote: > > > On Sat, 9 Feb 2019 09:20:53 +0100 > > > Brice Goglin <Brice.Goglin@xxxxxxxx> wrote: > > > > > > > Hello Keith > > > > > > > > Could we ever have a single side cache in front of two NUMA nodes ? I > > > > don't see a way to find that out in the current implementation. Would we > > > > have an "id" and/or "nodemap" bitmask in the sidecache structure ? > > > > > > This is certainly a possible thing for hardware to do. > > > > > > ACPI IIRC doesn't provide any means of representing that - your best > > > option is to represent it as two different entries, one for each of the > > > memory nodes. Interesting question of whether you would then claim > > > they were half as big each, or the full size. Of course, there are > > > other possible ways to get this info beyond HMAT, so perhaps the interface > > > should allow it to be exposed if available? > > > > HMAT doesn't do this, but I want this interface abstracted enough from > > HMAT to express whatever is necessary. > > > > The CPU cache is the closest existing exported attributes to this, > > and they provide "shared_cpu_list". To that end, I can export a > > "shared_node_list", though previous reviews strongly disliked multi-value > > sysfs entries. :( > > > > Would shared-node symlinks capture the need, and more acceptable? > > My inclination is that it's better to follow an existing pattern than > invent a new one that breaks people's expectations. > > However, don't feel that strongly about it as long as the interface > is functional and intuitive. Okay, considering I'd have a difficult time testing such an interface since it doesn't apply to HMAT, and I've received only conflicting feedback on list attributes, I would prefer to leave this feature out of this series for now. I'm certainly not against adding it later.
