[PATCH v7 3/4] arm64/arm, numa, dt: adding numa dt binding implementation for arm64 platforms.

[Ganapatrao Kulkarni]

On Sat, Nov 28, 2015 at 3:00 PM, Shannon Zhao <zhaoshenglong at huawei.com> wrote:
>
>
> On 2015/11/18 1:20, Ganapatrao Kulkarni wrote:
>> +static int __init early_init_parse_memory_node(unsigned long node)
>> +{
>> +     const __be32 *reg, *endp;
>> +     int length;
>> +     int nid;
>> +
>> +     const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
>> +
>> +     /* We are scanning "memory" nodes only */
>> +     if (type == NULL)
>> +             return 0;
>> +     else if (strcmp(type, "memory") != 0)
>> +             return 0;
>> +
>> +     nid = early_init_of_get_numa_nid(node);
>> +
>> +     if (nid == NUMA_NO_NODE)
>> +             return -EINVAL;
>> +
>> +     reg = of_get_flat_dt_prop(node, "reg", &length);
>> +     endp = reg + (length / sizeof(__be32));
>> +
>> +     while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
>> +             u64 base, size;
>> +             struct memblock_region *mblk;
>> +
>> +             base = dt_mem_next_cell(dt_root_addr_cells, &reg);
>> +             size = dt_mem_next_cell(dt_root_size_cells, &reg);
>> +             pr_debug("NUMA-DT:  base = %llx , node = %u\n",
>> +                             base, nid);
>> +
>> +             for_each_memblock(memory, mblk) {
>> +                     if (mblk->base == base) {
>> +                             if (numa_add_memblk(nid,
>> +                                                     mblk->base,
>> +                                                     mblk->size) < 0)
>> +                                     return -EINVAL;
>> +                             break;
>> +                     }
>> +             }
>
> Maybe this is not right. If the memory spaces of NUMA nodes are
> continuous like below:
>
>         memory at 60000000 {
>                 numa-node-id = <0x1>;
>                 reg = <0x0 0x60000000 0x0 0x20000000>;
>                 device_type = "memory";
>         };
>
>         memory at 40000000 {
>                 numa-node-id = <0x0>;
>                 reg = <0x0 0x40000000 0x0 0x20000000>;
>                 device_type = "memory";
>         };
>
> There is only one memory region [0x00000040000000-0x0000007fffffff] and
> the mblk->base is 40000000, so it will not add the memory node 1.
>
> I think this should do the same thing like ACPI_NUMA but add some codes
> to check if the [base, base + size] is located in some memory region.
> Or don't check because numa_add_memblk will fail if the [base, base +
> size] is not located in some memory region.
i am not sure, this kind of mapping we can have, since memblock can only map
contiguous region to only one numa node. however i can add a check as
you suggested.
Thanks for the review!.
>
> Thanks,
> --
> Shannon
>
thanks
Ganapat