Messages in this thread | | | Subject | Re: [PATCH] Documentation, dt, numa: Add note to empty NUMA node | From | Gavin Shan <> | Date | Thu, 24 Jun 2021 14:58:02 +1000 |
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On 6/24/21 12:14 PM, Randy Dunlap wrote: > On 6/23/21 8:37 PM, Gavin Shan wrote: >> The empty NUMA nodes, where no memory resides in, are allowed. For >> these empty NUMA nodes, the 'len' of 'reg' property is zero. These >> empty NUMA node IDs are still valid and parsed. I finds difficulty >> to get where it's properly documented. >> >> So lets add note to empty NUMA nodes in the NUMA binding doc. >> >> Signed-off-by: Gavin Shan <gshan@redhat.com> >> --- >> Documentation/devicetree/bindings/numa.txt | 4 ++++ >> 1 file changed, 4 insertions(+) >> >> diff --git a/Documentation/devicetree/bindings/numa.txt b/Documentation/devicetree/bindings/numa.txt >> index 21b35053ca5a..c564705c0eac 100644 >> --- a/Documentation/devicetree/bindings/numa.txt >> +++ b/Documentation/devicetree/bindings/numa.txt >> @@ -109,6 +109,10 @@ Example: >> Dual socket system consists of 2 boards connected through ccn bus and >> each board having one socket/soc of 8 cpus, memory and pci bus. >> >> +Note that the empty NUMA nodes, which no memory resides in, are allowed > > Missing period at end of the sentence above. >
Oh, Yes. Thanks, Randy. I will replace "resides in" with "resides in period" in v2.
>> +Their NUMA node IDs are still valid so that memory can be added into these >> +NUMA nodes through hotplug afterwards. >> + >> memory@c00000 { >> device_type = "memory"; >> reg = <0x0 0xc00000 0x0 0x80000000>;
By the way, I have one more question to check with you if I can. I'm not sure if dummy and invalid 'unit-address' is allowed in the empty memory node name, which follows the format "memory@unit-address'.
(1) The 'unit-address' is same thing as to 'base address' for memory node, as specified in device-tree specification. I'm not sure if 'base address' can be dummy and invalid one since empty memory node doesn't have memory at all.
https://devicetree-specification.readthedocs.io/en/latest/chapter2-devicetree-basics.html#node-names
(2) I don't find the 'unit-address' is used in linux, but I'm not sure other software component like firmware uses it or not.
Thanks, Gavin
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