Re: [PATCH] mm: Make allocator take care of memoryless numa node

[Christopher Lameter]

On Mon, 12 Oct 2020, Xianting Tian wrote:

> In architecture like powerpc, we can have cpus without any local memory
> attached to it. In such cases the node does not have real memory.
>
> In many places of current kernel code, it doesn't judge whether the node is
> memoryless numa node before calling allocator interface.

That is intentional. SLUB relies on the page allocator to pick a node.

> This patch is to use local_memory_node(), which is guaranteed to have
> memory, in allocator interface. local_memory_node() is a noop in other
> architectures that don't support memoryless nodes.

The patch would destroy the support for memory policies in the
SLUB allocator and likely in the other ones as well.