Re: [PATCH for 2.6.16] Handle holes in node mask in node fallback list initialization

[Christoph Lameter <clameter@engr.sgi.com>]

On Fri, 17 Feb 2006, Andi Kleen wrote:

> No, in theory not, but changing that would require considerable changes 
> in the NUMA discovery code and I'm not planning to do that for 2.6.16 now.

Are you sure that the kernel can handle nodelists with holes everywhere? 
This is essentially a new feature requiring a review of all uses of 
node ranges.... I'd rather suggest to fix the arch.

> Also I think the generic code ought to handle that anyways. Why should
> we have node bitmaps if they can't have holes?

There are special cases for example in the slab allocator and possibly 
elsewhere too. F.e. have a look at __alloc_percpu which must allocate 
memory for cpus on offline nodes. These will then never be used. So 
hopefully not an issue just a waste of memory. There is more in 
alloc_alien_cache(). That is just the stuff that I know about off hand. 

> > ia64 has a lookup table. 
> x86-64 too.

So this is fixable in arch specific code.

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>