Re: [PATCH 6/6] hugetlb: update hugetlb documentation for mempolicy based management.

Mel Gorman
2009-09-16T10:21:24Z

On Mon, Sep 14, 2009 at 02:28:27PM -0700, David Rientjes wrote:
> On Mon, 14 Sep 2009, David Rientjes wrote:
>
> > > On PPC64, the parameters behave differently. I couldn't convince it to
> > > create more than one NUMA node. On x86-64, the NUMA nodes appeared to
> > > exist and would be visible on /proc/buddyinfo for example but the sysfs
> > > directories for the fake nodes were not created so nr_hugepages couldn't
> > > be examined on a per-node basis for example.
> > >
> >
> > I don't know anything about the ppc64 fake NUMA, but the sysfs node
> > directories should certainly be created on x86_64. I'll look into it
> > because that's certainly a bug. Thanks.
> >
>
> This works on my machine just fine.
>
> For example, with numa=fake=8:
>
> $ ls /sys/devices/system/node
> has_cpu has_normal_memory node0 node1 node2 node3 node4
> node5 node6 node7 online possible
>
> $ ls /sys/devices/system/node/node3
> cpu4 cpu5 cpu6 cpu7 cpulist cpumap distance meminfo
> numastat scan_unevictable_pages
>
> I don't see how this could differ if bootmem is setting up the nodes
> correctly, which dmesg | grep "^Bootmem setup node" would reveal.
>
> The defconfig disables CONFIG_NUMA_EMU now, though, so perhaps it got
> turned off by accident in your kernel?
>

I don't think so because my recollection is that the nodes existed
according to meminfo and buddyinfo but not the sysfs files.
Unfortunately I can't remember the reproduction scenario. I thought it
was on mmotm-2009-08-27-16-51 on a particularly machine but when I went
to reproduce, it didn't even boot so somewhere along the line I busted
things.

> Let me know if there's any abnormalities with your particular setup.
>

Will try reproducing on more recent mmotm and see if anything odd falls
out.

--
Mel Gorman
Part-time Phd Student Linux Technology Center
University of Limerick IBM Dublin Software Lab

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