On 2015/8/29 22:56, Ganapatrao Kulkarni wrote:
> Hi Thunder,
>
> On Sat, Aug 29, 2015 at 3:16 PM, Leizhen (ThunderTown)
> <thunder.leizhen@xxxxxxxxxx> wrote:
>>
>>
>> On 2015/8/28 22:02, Rob Herring wrote:
>>> +benh
>>>
>>> On Fri, Aug 28, 2015 at 7:32 AM, Mark Rutland <mark.rutland@xxxxxxx> wrote:
>>>> Hi,
>>>>
>>>> On Fri, Aug 14, 2015 at 05:39:32PM +0100, Ganapatrao Kulkarni wrote:
>>>>> DT bindings for numa map for memory, cores and IOs using
>>>>> arm,associativity device node property.
>>>>
>>>> Given this is just a copy of ibm,associativity, I'm not sure I see much
>>>> point in renaming the properties.
>>>
>>> So just keep the ibm? I'm okay with that. That would help move to
>>> common code. Alternatively, we could drop the vendor prefix and have
>>> common code just check for both.
>>>
>>
>> Hi all,
>>
>> Why not copy the method of ACPI numa? There only three elements should be configured:
>> 1) a cpu belong to which node
>> 2) a memory block belong to which node
>> 3) the distance of each two nodes
>>
>> The devicetree nodes of numa can be like below:
>> / {
>> ...
>>
>> numa-nodes-info {
>> node-name: node-description {
>> mem-ranges = <...>;
>> cpus-list = <...>;
>> };
>>
>> nodes-distance {
>> distance-list = <...>;
>> };
>> };
>>
>> ...
>> };
>>
> some what similar to what your are proposing is already implemented in
> my v2 patchset.
> https://lwn.net/Articles/623920/
> http://lists.infradead.org/pipermail/linux-arm-kernel/2014-November/305164.html
Sorry, I have not read your old version patchsets before.
The basic ideas are consistent, but details are different. I think your v2 patchset may meet some problem:
-------------------------
+- cpu-map: This property defines the association of range of processors
+ (range of cpu ids) and the proximity domain to which
+ the processor belongs.
+ cpu-map = <0 7 0>,
+ <8 15 1>;
-------------------------
1.
I am not sure the cpu ids is logical cpu-ids in Linux or the sequence number of the CPU dt-nodes in dts.
The former case: logical cpu-id is allocated by Linux, we can not ensure that cpu0 is the first CPU dt-node.
The latter case: depend on Linux strictly parse CPU dt-nodes follow the sequence in dts.
2. You should put most codes into /drivers/of/, because it can be shared with other ARCHs which base upon devicetree.
Here is my detailed example:
Examples:
/ {
#address-cells = <2>;
#size-cells = <2>;
memory@0 {
device_type = "memory";
reg = <0x0 0x00000000 0x0 0x40000000>,
<0x1 0x00000000 0x1 0x00000000>,
<0x2 0x00000000 0x0 0x40000000>,
<0x2 0x80000000 0x0 0x40000000>;
};
CPU0: cpu@10000 {
device_type = "cpu";
reg = <0x10000>;
...
};
numa-nodes-info {
node0: cluster0 {
mem-ranges = <0x0 0x00000000 0x1 0x00000000>;
cpus-list = <&CPU0 &CPU1>;
};
node1: cluster1 {
mem-ranges = <0x1 0x00000000 0x1 0x00000000>;
cpus-list = <&CPU2>;
};
node2: cluster2 {
mem-ranges = <0x2 0x00000000 0x1 0x00000000>;
cpus-list = <&CPU3 &CPU4 &CPU5>;
};
nodes-distance {
distance-list = <&node0 &node1 15>, <&node1 &node2 18>;
};
};
> we have went to associativity property based implementation to keep it
> more generic.
> i do have both acpi(using linaro/hanjun's patches) and associativity
> based implementations on our internal tree
> and tested on thunderx platform.
> i do see issue in creating numa mapping using ACPI for IOs(for
> example, i am not able to create numa mapping for ITS which is on each
> node, using ACPI tables), since ACPI spec (tables SRAT and SLIT)
> talks only about processor and memory.
> however associativity is generic and you can apply on any dt node.
>> Sorry, I don't think xxx,associativity is a good method, it's hard to config, and it
>> seems hardware-dependent. Especially, when we want to support memory hot-add, it's too hard.
>> Because xxx,associativity have no obvious information about it. Like powerpc, it use another
>> property: "/ibm,dynamic-reconfiguration-memory".
>>
>> I spend almost a whole month to implement of_numa(configured by dt-nodes), base upon my opinion
>> mentioned above. If somebody are interested in it, I can send my patchset to show it.
>>
>> Regards,
>> Thunder.
>>
> thanks
> ganapat
>
> .
>
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