Re: [PATCH v4][RFC] hugetlb: add per-node nr_hugepages sysfs attribute

[Lee Schermerhorn <Lee.Schermerhorn@hp.com>]

On Mon, 2007-07-23 at 12:23 -0700, Christoph Lameter wrote:
> On Wed, 13 Jun 2007 16:05:10 -0400
> Lee Schermerhorn <Lee.Schermerhorn@hp.com> wrote:
> 
> > I tried to "tighten up"  alloc_pages_node() to check the location of
> > the first zone in the selected zonelist, as discussed in previous
> > exchange. When I do this, I hit a BUG() in slub.c in
> > early_kmem_cache_node_alloc(), as it apparently can't handle
> > new_slab() returning a NULL page, even tho' it calls it with
> > GFP_THISNODE.  Slub should be able to handle memoryless nodes,
> > right?  I'm looking for a work around to this now.
> 
> The memoryless node patchset results in SLUB not attempting to allocate
> on memoryless nodes during bootstrap.
> 

Christoph:

The message that you're responding to is from 13jun, before your
memoryless nodes patch.  We discussed it and have more or less resolved
it.  I was trying to ensure that GFP_THISNODE would fail on my funky
interleaved node with just DMA memory, when you ask for a higher zone.
I.e., no fallback.  You disagreed with this, so I'm waiting for the
memoryless nodes patches to get into -mm, so I can address the issue of
hugepages [and regular interleaved pages] being allocated from a node
where they shouldn't on my platform.  

This has been discussed in the past week by Nish, Paul Mundt, and others
in the -mm thread:

	[hugetlb] Try to grow pool for MAP_SHARED mappings

I think we can handle the fundamental issue [even nodes with memory are
not necessarily candidates for interleave, hugepages, ...] by adding
another node_state[].  See the mentioned thread.

Lee

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