Re: [PATCH 16/17] arch_numa: switch over to numa_memblks

Jonathan Cameron
2024-07-19T18:16:06Z

On Tue, 16 Jul 2024 14:13:45 +0300
Mike Rapoport <rppt@kernel.org> wrote:

> From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
>
> Until now arch_numa was directly translating firmware NUMA information
> to memblock.
>
> Using numa_memblks as an intermediate step has a few advantages:
> * alignment with more battle tested x86 implementation
> * availability of NUMA emulation
> * maintaining node information for not yet populated memory
>
> Replace current functionality related to numa_add_memblk() and
> __node_distance() with the implementation based on numa_memblks and add
> functions required by numa_emulation.
>
> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

One trivial comment inline,

Jonathan
> /*
> * Initialize NODE_DATA for a node on the local memory
> */
> @@ -226,116 +204,9 @@ static void __init setup_node_data(int nid, u64 start_pfn, u64 end_pfn)
> NODE_DATA(nid)->node_spanned_pages = end_pfn - start_pfn;
> }

>
> @@ -454,3 +321,54 @@ void __init arch_numa_init(void)
>
> numa_init(dummy_numa_init);
> }
> +
> +#ifdef CONFIG_NUMA_EMU
> +void __init numa_emu_update_cpu_to_node(int *emu_nid_to_phys,
> + unsigned int nr_emu_nids)
> +{
> + int i, j;
> +
> + /*
> + * Transform __apicid_to_node table to use emulated nids by

Comment needs an update seeing as there is no __apicid_to_node table
here.

> + * reverse-mapping phys_nid. The maps should always exist but fall
> + * back to zero just in case.
> + */
> + for (i = 0; i < ARRAY_SIZE(cpu_to_node_map); i++) {
> + if (cpu_to_node_map[i] == NUMA_NO_NODE)
> + continue;
> + for (j = 0; j < nr_emu_nids; j++)
> + if (cpu_to_node_map[i] == emu_nid_to_phys[j])
> + break;
> + cpu_to_node_map[i] = j < nr_emu_nids ? j : 0;
> + }
> +}
> +
> +u64 __init numa_emu_dma_end(void)
> +{
> + return PFN_PHYS(memblock_start_of_DRAM() + SZ_4G);
> +}