On Thursday, June 11, 2015 04:10:47 PM Dan Williams wrote: > A "region" device represents the maximum capacity of a BLK range (mmio > block-data-window(s)), or a PMEM range (DAX-capable persistent memory or > volatile memory), without regard for aliasing. Aliasing, in the > dimm-local address space (DPA), is resolved by metadata on a dimm to > designate which exclusive interface will access the aliased DPA ranges. > Support for the per-dimm metadata/label arrvies is in a subsequent > patch. > > The name format of "region" devices is "regionN" where, like dimms, N is > a global ida index assigned at discovery time. This id is not reliable > across reboots nor in the presence of hotplug. Look to attributes of > the region or static id-data of the sub-namespace to generate a > persistent name. However, if the platform configuration does not change > it is reasonable to expect the same region id to be assigned at the next > boot. > > "region"s have 2 generic attributes "size", and "mapping"s where: > - size: the BLK accessible capacity or the span of the > system physical address range in the case of PMEM. > > - mappingN: a tuple describing a dimm's contribution to the region's > capacity in the format (<nmemX>,<dpa>,<size>). For a PMEM-region > there will be at least one mapping per dimm in the interleave set. For > a BLK-region there is only "mapping0" listing the starting DPA of the > BLK-region and the available DPA capacity of that space (matches "size" > above). > > The max number of mappings per "region" is hard coded per the > constraints of sysfs attribute groups. That said the number of mappings > per region should never exceed the maximum number of possible dimms in > the system. If the current number turns out to not be enough then the > "mappings" attribute clarifies how many there are supposed to be. "32 > should be enough for anybody...". > > Cc: Neil Brown <neilb@xxxxxxx> > Cc: <linux-acpi@xxxxxxxxxxxxxxx> > Cc: Greg KH <gregkh@xxxxxxxxxxxxxxxxxxx> > Cc: Robert Moore <robert.moore@xxxxxxxxx> > Cc: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> > Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx> For the ACPI part: Acked-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
