Messages in this thread | | | Date | Tue, 10 Jun 2008 15:37:02 -0400 | From | Rik van Riel <> | Subject | Re: [PATCH -mm 13/25] Noreclaim LRU Infrastructure |
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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 :)
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