Messages in this thread | | | Date | Wed, 11 Jun 2008 15:29:22 +0900 | From | Paul Mundt <> | Subject | Re: [PATCH -mm 13/25] Noreclaim LRU Infrastructure |
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On Tue, Jun 10, 2008 at 11:16:42PM -0700, Andrew Morton wrote: > On Wed, 11 Jun 2008 14:09:15 +0900 Paul Mundt <lethal@linux-sh.org> wrote: > > On Tue, Jun 10, 2008 at 02:33:34PM -0700, Andrew Morton wrote: > > > Maybe it's time to bite the bullet and kill i386 NUMA support. afaik > > > it's just NUMAQ and a 2-node NUMAish machine which IBM made (as400?) > > > > > > arch/sh uses NUMA for 32-bit, I believe. But I don't know what its > > > maximum node count is. The default for sh NODES_SHIFT is 3. > > > > In terms of memory nodes, systems vary from 2 up to 16 or so. It gets > > gradually more complex in the SMP cases where we are 3-4 levels deep in > > various types of memories that we expose as nodes (ie, 4-8 CPUs with a > > dozen different memories or so at various interconnect levels). > > Thanks. > > Andi has suggested that we can remove the node-ID encoding from > page.flags on x86 because that info is available elsewhere, although a > bit more slowly. > > <looks at page_zone(), wonders whether we care about performance anyway> > > There wouldn't be much point in doing that unless we did it for all > 32-bit architectures. How much trouble would it cause sh? > At first glance I don't think that should be too bad. We only do NUMA through sparsemem anyways, and we have pretty much no overlap in any of the ranges, so simply setting NODE_NOT_IN_PAGE_FLAGS should be ok there. Given the relatively small number of pages we have, the added cost of page_to_nid() referencing section_to_node_table should still be tolerable. I'll give it a go and see what the numbers look like.
> > As far as testing goes, it's part of the regular build and regression > > testing for a number of boards, which we verify on a daily basis > > (although admittedly -mm gets far less testing, even though that's where > > most of the churn in this area tends to be). > > Oh well, that's what -rc is for :( > > It would be good if someone over there could start testing linux-next. > Once I get my act together that will include most-of-mm anyway. > Agreed. This is something we're attempting to add in to our automated testing at present.
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