Re: [PATCH v5 02/11] mm/mempolicy: introduce MPOL_WEIGHTED_INTERLEAVE for weighted interleaving

[Gregory Price]

On Fri, Jan 05, 2024 at 02:51:40PM +0800, Huang, Ying wrote:
> >
> > So we're talking ~1MB for 1024 threads with mempolicies to avoid error
> > conditions mid-page-allocation and to reduce the cost associated with
> > applying weighted interleave.
> 
> Think about this again.  Why do we need weights array on stack?  I think
> this is used to keep weights consistent.  If so, we don't need weights
> array on stack.  Just use RCU to access global weights array.
> 

>From the bulk allocation code:

__alloc_pages_bulk(gfp, node, NULL, node_pages, NULL, page_array);

This function can block. You cannot block during an RCU read context.

~Gregory