powerpc/pseries: Add support for hash table resizing

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This adds support for using two hypercalls to change the size of the
main hash page table while running as a PAPR guest. For now these
hypercalls are only in experimental qemu versions.

The interface is two part: first H_RESIZE_HPT_PREPARE is used to
allocate and prepare the new hash table. This may be slow, but can be
done asynchronously. Then, H_RESIZE_HPT_COMMIT is used to switch to the
new hash table. This requires that no CPUs be concurrently updating the
HPT, and so must be run under stop_machine().

This also adds a debugfs file which can be used to manually control
HPT resizing or testing purposes.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
Reviewed-by: Paul Mackerras <paulus@samba.org>
[mpe: Rename the debugfs file to "hpt_order"]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

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David Gibson 2016-12-09 11:07:36 +11:00 • committed by Michael Ellerman

parent 64b40ffbc8

commit dbcf929c00

3 changed files with 143 additions and 0 deletions

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1

arch/powerpc/include/asm/book3s/64/mmu-hash.h

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33

arch/powerpc/mm/hash_utils_64.c

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109

arch/powerpc/platforms/pseries/lpar.c

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