Re: [PATCH 1/2] arm64: avoid alloc memory on offline node

[Punit Agrawal <punit.agrawal@arm.com>]

Punit Agrawal <punit.agrawal@arm.com> writes:


[...]

>
> CONFIG_HAVE_MEMORYLESS node is not enabled on arm64 which means we end
> up returning the original node in the fallback path.
>
> Xie, does the below patch help? I can submit a proper patch if this
> fixes the issue for you.
>
> -- >8 --
> Subject: [PATCH] arm64/numa: Enable memoryless numa nodes
>
> Signed-off-by: Punit Agrawal <punit.agrawal@arm.com>
> ---
>  arch/arm64/Kconfig   | 4 ++++
>  arch/arm64/mm/numa.c | 2 ++
>  2 files changed, 6 insertions(+)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index eb2cf4938f6d..5317e9aa93ab 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -756,6 +756,10 @@ config USE_PERCPU_NUMA_NODE_ID
>  	def_bool y
>  	depends on NUMA
>  
> +config HAVE_MEMORYLESS_NODES
> +       def_bool y
> +       depends on NUMA
> +
>  config HAVE_SETUP_PER_CPU_AREA
>  	def_bool y
>  	depends on NUMA
> diff --git a/arch/arm64/mm/numa.c b/arch/arm64/mm/numa.c
> index dad128ba98bf..c699dcfe93de 100644
> --- a/arch/arm64/mm/numa.c
> +++ b/arch/arm64/mm/numa.c
> @@ -73,6 +73,8 @@ EXPORT_SYMBOL(cpumask_of_node);
>  static void map_cpu_to_node(unsigned int cpu, int nid)
>  {
>  	set_cpu_numa_node(cpu, nid);
> +	set_numa_mem(local_memory_node(nid));

Argh, this should be

        set_cpu_numa_mem(cpu, local_memory_node(nid));

There is not guarantee that map_cpu_to_node() will be called on the
local cpu.

Hanjun, Xie - can you try with the update please?

Thanks,
Punit

> +
>  	if (nid >= 0)
>  		cpumask_set_cpu(cpu, node_to_cpumask_map[nid]);
>  }