* Michael Ellerman <m...@ellerman.id.au> [2020-07-07 15:02:17]: > Srikar Dronamraju <sri...@linux.vnet.ibm.com> writes: > > As per PAPR, there are 2 device tree property > > ibm,max-associativity-domains (which defines the maximum number of > > domains that the firmware i.e PowerVM can support) and > > ibm,current-associativity-domains (which defines the maximum number of > > domains that the platform can support). Value of > > ibm,max-associativity-domains property is always greater than or equal > > to ibm,current-associativity-domains property. > > Where is it documented? > > It's definitely not in LoPAPR. >
https://openpowerfoundation.org/wp-content/uploads/2020/07/LoPAR-20200611.pdf Page number 833. which says ibm,current-associativity-domainsâ property name to define the current number of associativity domains for this platform. prop-encoded-array: An associativity list such that all values are the number of unique values that the current platform supports in that location. The associativity list consisting of a number of entries integer (N) encoded as with encode-int followed by N integers encoded as with encode-int each representing current number of unique associativity domains the platform supports at that level. > > Powerpc currently uses ibm,max-associativity-domains property while > > setting the possible number of nodes. This is currently set at 32. > > However the possible number of nodes for a platform may be significantly > > less. Hence set the possible number of nodes based on > > ibm,current-associativity-domains property. > > > > $ lsprop /proc/device-tree/rtas/ibm,*associ*-domains > > /proc/device-tree/rtas/ibm,current-associativity-domains > > 00000005 00000001 00000002 00000002 00000002 00000010 > > /proc/device-tree/rtas/ibm,max-associativity-domains > > 00000005 00000001 00000008 00000020 00000020 00000100 > > > > $ cat /sys/devices/system/node/possible ##Before patch > > 0-31 > > > > $ cat /sys/devices/system/node/possible ##After patch > > 0-1 > > > > Note the maximum nodes this platform can support is only 2 but the > > possible nodes is set to 32. > > But what about LPM to a system with more nodes? > I have very less info on LPM, so I checked with Nathan Lynch before posting and as per Nathan in the current design of LPM, Linux wouldn't use the new node numbers. -- Thanks and Regards Srikar Dronamraju