Re: [PATCH v4 2/2] RISC-V: Implement sparsemem

[Greentime Hu <green.hu@gmail.com>]

Hi Logan,

Logan Gunthorpe <logang@deltatee.com> 於 2019年8月1日 週四 上午1:08寫道：
>
>
>
> On 2019-07-31 12:30 a.m., Greentime Hu wrote:
> > I look this issue more closely.
> > I found it always sets each memblock region to node 0. Does this make sense?
> > I am not sure if I understand this correctly. Do you have any idea for
> > this? Thank you. :)
>
> Yes, I think this is normal. When we talk about memory nodes we're
> talking about NUMA nodes which is unrelated to device tree nodes.

Ok, but it seems the second memblock_region may overwrite the first
memblock_region in for_each_memblock(memory, reg)  loop. It always
uses this API to set to node 0.
memblock_set_node(PFN_PHYS(start_pfn),PFN_PHYS(end_pfn - start_pfn),
&memblock.memory,0)


> I'm not really sure what's causing the crash. Have you verified it's
> this patch that causes it? Is it related to there being a hole in your
> memory, does it work if you only have one memory node?
>

It works fine if there is only one memory node described in dts.

I think it is related to there being a hole in the device tree script.
I don't actually have a platform with a hole in the memory region, so
I use device tree script to describe it.

The physical address layout will be like this.
2GB-3GB-hole-6GB-7GB

memory@80000000 {
    device_type = "memory";
    reg = <0x0 0x80000000 0x0 0x40000000>;
};
memory@180000000 {
    device_type = "memory";
    reg = <0x1 0x80000000 0x0 0x40000000>;
};

Thank you for the quick reply. :)

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