Re: [RFC PATCH v2 0/3] mm: mempolicy: Multi-tier weighted interleaving

[Gregory Price]

On Mon, Oct 23, 2023 at 10:09:56AM +0800, Huang, Ying wrote:
> Gregory Price <gregory.price@xxxxxxxxxxxx> writes:
> 
> > Depends.  if a user explicitly launches with `numactl --cpunodebind=0`
> > then yes, you can force a task (and all its children) to run on node0.
> 
> IIUC, in your example, the `numactl` command line will be
> 
>   numactl --cpunodebind=0 --weighted-interleave=0,1,2,3
> 
> That is, the CPU is restricted to node 0, while memory is distributed to
> all nodes.  This doesn't sound like reasonable for me.
> 

It being reasonable isn't really relevant. You can do this today with
normal interleave:

numactl --cpunodebind=0 --interleave=0,1,2,3

The only difference between this method and that is the application of
weights.  Doesn't seem reasonable to lock users out of doing it.

> 
> IMHO, we should keep thing as simple as possible, only add complexity if
> necessary.
>

Not allowing it is more complicated than allowing it.