Re: [PATCH] Fix hugetlb pool allocation with empty nodes - V2

["Nish Aravamudan" <nish.aravamudan@gmail.com>]

On 5/4/07, Christoph Lameter <clameter@sgi.com> wrote:
> On Fri, 4 May 2007, Lee Schermerhorn wrote:
>
> > On Wed, 2007-05-02 at 21:21 -0500, Anton Blanchard wrote:
> > > An interesting bug was pointed out to me where we failed to allocate
> > > hugepages evenly. In the example below node 7 has no memory (it only has
> > > CPUs). Node 0 and 1 have plenty of free memory. After doing:
> >
> > Here's my attempt to fix the problem [I see it on HP platforms as well],
> > without removing the population check in build_zonelists_node().  Seems
> > to work.
>
> I think we need something like for_each_online_node for each node with
> memory otherwise we are going to replicate this all over the place for
> memoryless nodes. Add a nodemap for populated nodes?
>
> I.e.
>
> for_each_mem_node?
>
> Then you do not have to check the zone flags all the time. May avoid a lot
> of mess?

I agree -- and we'd keep hugetlb.c relatively node-unaware. hugetlb.c
would only need the nodemap, I believe, and we could just change

               nid = next_node(nid, node_online_map);
               if (nid == MAX_NUMNODES)
                       nid = first_node(node_online_map);

to use mem_node_map or whatever it would be called (node_mem_map looks
weird to me (why is it node_online_map but for_each_online_node() ?)

Thanks,
Nish

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