On Wed, Dec 20, 2017 at 12:22:21PM -0800, Dave Hansen wrote: > On 12/20/2017 10:19 AM, Matthew Wilcox wrote: > > I don't know what the right interface is, but my laptop has a set of > > /sys/devices/system/memory/memoryN/ directories. Perhaps this is the > > right place to expose write_bw (etc). > > Those directories are already too redundant and wasteful. I think we'd > really rather not add to them. In addition, it's technically possible > to have a memory section span NUMA nodes and have different performance > properties, which make it impossible to represent there. > > In any case, ACPI PXM's (Proximity Domains) are guaranteed to have > uniform performance properties in the HMAT, and we just so happen to > always create one NUMA node per PXM. So, NUMA nodes really are a good fit. I think you're missing my larger point which is that I don't think this should be exposed to userspace as an ACPI feature. Because if you do, then it'll also be exposed to userspace as an openfirmware feature. And sooner or later a devicetree feature. And then writing a portable program becomes an exercise in suffering. So, what's the right place in sysfs that isn't tied to ACPI? A new directory or set of directories under /sys/devices/system/memory/ ? -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
