[PATCH] mm: rename and document alloc_pages_exact_node

[David Rientjes]

On Thu, 23 Jul 2015, Christoph Lameter wrote:

> > The only possible downside would be existing users of
> > alloc_pages_node() that are calling it with an offline node.  Since it's a
> > VM_BUG_ON() that would catch that, I think it should be changed to a
> > VM_WARN_ON() and eventually fixed up because it's nonsensical.
> > VM_BUG_ON() here should be avoided.
> 
> The offline node thing could be addresses by using numa_mem_id()?
> 

I was concerned about any callers that were passing an offline node, not 
NUMA_NO_NODE, today.  One of the alloc-node functions has a VM_BUG_ON() 
for it, the other silently calls node_zonelist() on it.

I suppose the final alloc_pages_node() implementation could be

        if (nid == NUMA_NO_NODE || VM_WARN_ON(!node_online(nid)))
                nid = numa_mem_id();

        VM_BUG_ON(nid < 0 || nid >= MAX_NUMNODES);
        return __alloc_pages(gfp_mask, order, node_zonelist(nid, gfp_mask));

though.