Re: [RFC PATCH] mm: migrate: Add new node demotion strategy

[Baolin Wang]

On 2021/11/7 23:20, Dave Hansen wrote:
> On 11/7/21 1:33 AM, Baolin Wang wrote:
> > Thanks for your suggestion. After some thinking, can we change the
> > node_demotion[] structure like below? Which means one source node can be
> > demoted to mutiple target node, and we can set up the target node mask
> > according to the node distance. How do you think? Thanks.
> >
> > static nodemask_t node_demotion[MAX_NUMNODES] __read_mostly =
> >          {[0 ...  MAX_NUMNODES - 1] = NODE_MASK_NONE};
>
> How large is that in the worst case?

For the worst case (MAX_NUMNODES=1024), the size of the node_demotion is 
131072 bytes, while the size of original data structure is 4096 bytes. 
Maybe we can allocate the node_demotion dynamically?