On Wed, 2017-05-03 at 16:08 -0700, Dan Williams wrote: > On Wed, May 3, 2017 at 3:51 PM, Dan Williams <[email protected] > m> wrote: > > On Wed, May 3, 2017 at 3:41 PM, Kani, Toshimitsu <[email protected] > > m> wrote: > > > On Wed, 2017-05-03 at 14:48 -0700, Dan Williams wrote: : > > > > I believe we already have all the data needed to calculate the data > > offset. Given the following sysfs path: > > > > /sys/devices/LNXSYSTM:00/LNXSYBUS:00/ACPI0012:00/ndbus0/region1 > > /dax1.1/dax/dax1.0 > > > > ...we can find the associated namespace device from that dax1.1. > > From > > there we have the base address of the namespace and the size > > device-dax instance. > > > > device_dax_data_offset == namespace_base + namespace_size - > > device_dax_size > > Dave reminds me that we do have the data offset of the device-dax > instance at the libnvdimm level: > > /sys/devices/LNXSYSTM:00/LNXSYBUS:00/ACPI0012:00/ndbus0/region1/d > ax1.1/resource > > ...in this example, which maps to ndctl_dax_get_resource().
Thanks for the info! I noticed why I did not catch this info before. # ll /dev/dax* crw------- 1 root root 251, 3 May 3 04:28 /dev/dax0.0 # pwd /sys/devices/LNXSYSTM:00/LNXSYBUS:00/ACPI0012:00/ndbus0/region0/dax0.0 # grep . * align:2097152 devtype:nd_dax modalias:nd:t7 mode:none numa_node:0 grep: power: Is a directory grep: resource: No such device or address grep: size: No such device or address grep: subsystem: Is a directory uevent:DEVTYPE=nd_dax uevent:MODALIAS=nd:t7 But I noticed that "resource" and "size" that are under ".../region0/dax0.1" work. Is this intended? -Toshi
