powerpc/64s/hash: add stress_hpt kernel boot option to increase hash faults

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This option increases the number of hash misses by limiting the number
of kernel HPT entries, by keeping a per-CPU record of the last kernel
HPTEs installed, and removing that from the hash table on the next hash
insertion. A timer round-robins CPUs removing remaining kernel HPTEs and
clearing the TLB (in the case of bare metal) to increase and slightly
randomise kernel fault activity.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Add comment about NR_CPUS usage, fixup whitespace]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221024030150.852517-1-npiggin@gmail.com

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Nicholas Piggin 2022-10-24 13:01:50 +10:00 • committed by Michael Ellerman

parent dfecd06bc5

commit 6b34a099fa

5 changed files with 160 additions and 1 deletions

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5

Documentation/admin-guide/kernel-parameters.txt

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5

arch/powerpc/mm/book3s64/hash_4k.c

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arch/powerpc/mm/book3s64/hash_64k.c

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arch/powerpc/mm/book3s64/hash_utils.c

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arch/powerpc/mm/book3s64/internal.h

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