libhugetlbfs and sparc64 support

[Nishanth Aravamudan <nacc@us.ibm.com>]

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Hello all,

I'm currently trying to add (basic) support for sparc64 to libhugetlbfs.
If nothing else, this will ensure that sparc64 gets adequate testing. I
am finding, though, that using the attached tarball and running `make
func`, which should run through a series of quick functional tests, an
Ultra 60 I have access to hangs hard. To be clear, I'm not ruling out
general instability, but same box is able to build kernels and I'm more
prone to suspect hugepage support in the kernel.

What I'm seeing:

1) Running only the 32-bit tests (by specifying -b32 to
tests/run_test.sh), immediately after readpage finishes, the box hangs
hard, including serial console (has to be power cycled). No oops,
nothing.

2) Running only the 64-bit tests (-b64 to run_tests.sh), immediately
after unlinked_fd finishes, the box hangs similarly. Again, nothing on
the serial console to indicate a problem.

What I'm hoping to get is some help from folks that are sparc-savvy. Is
the box just busted, and maybe I should try to find another? Or are
people able to see similar problems running `make func`.

To reproduce:

Use 2.6.20.2, if possible, to avoid as many known hugepage bugs in
arch-generic code as possible. CONFIG_HUGETLBFS and CONFIG_HUGETLB_PAGE
set (the former selects the latter). Boot with hugepages=20 (or `echo 20
> /proc/sys/vm/nr_hugepages`). Using the attached tarball, run
`make func`. Tell me what happens :)

Note: I fully expect some test to fail, notably icache-hygeiene,
linkhuge and linkshare (the latter because the linker scripts in the
tarball are just dummy copies of the normal .x ones).

If someone could also verify my sparc assembly in elf32_sparc.S and
elf64_sparc.S, I would greatly appreciate it.

Thanks,
Nish

-- 
Nishanth Aravamudan <nacc@us.ibm.com>
IBM Linux Technology Center


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