Le 11/02/2019 à 16:23, Keith Busch a écrit : > 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? As a user-space guy reading these files/symlinks, I would prefer reading a bitmask just like we do for CPU cache "cpumap" or CPU "siblings" files (or sibling_list). Reading a directory and looking for dentries matching "foo%d" is far less convenient in C. If all these files are inside a dedicated subdirectory, it's better but still not as easy. Brice
