Messages in this thread | | | Date | Tue, 10 Jun 2008 14:33:34 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH -mm 13/25] Noreclaim LRU Infrastructure |
| |
On Tue, 10 Jun 2008 15:37:02 -0400 Rik van Riel <riel@redhat.com> wrote:
> On Tue, 10 Jun 2008 12:17:23 -0700 (PDT) > Christoph Lameter <clameter@sgi.com> wrote: > > > On Sun, 8 Jun 2008, Andrew Morton wrote: > > > > > And it will take longer to get those problems sorted out if 32-bt > > > machines aren't even compiing the new code in. > > > > The problem is going to be less if we dependedn on > > CONFIG_PAGEFLAGS_EXTENDED instead of 64 bit. This means that only certain > > 32bit NUMA/sparsemem configs cannot do this due to lack of page flags. > > > > I did the pageflags rework in part because of Rik's project. > > I think your pageflags work freed up a number of bits on 32 > bit systems, unless someone compiles a 32 bit system with > support for 4 memory zones (2 bits ZONE_SHIFT) and 64 NUMA > nodes (6 bits NODE_SHIFT), in which case we should still > have 24 bits for flags. > > Of course, having 64 NUMA nodes and a ZONE_SHIFT of 2 on > a 32 bit system is probably total insanity already. I > suspect very few people compile 32 bit with NUMA at all, > except if it is an architecture that uses DISCONTIGMEM > instead of zones, in which case ZONE_SHIFT is 0, which > will free up space too :)
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.
| |