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    Subject[PATCH 0/2] Fix how CPUs are enumerated when there's more than 255 CPUs
    Date
    This series of patches attempts to fix how CPUs are enumerated by kernel when
    there's more than 255 of them on single processor.
    In such case, BIOS may interleave APIC/X2APIC MADT subtables, to obey requirements
    specified in ACPI spec. Without this patches, kernel then would first enumerate
    BSP, then X2APIC then APIC, resulting in low APIC IDs to be assigned with high
    logical IDs and high APIC IDs to be assigned low logical IDs. Biggest consequence
    of that could be performance penalties due to wrong L2 cache sharing.
    More details in patch 2/2.

    Also, simpler approach has been considered, which did not required ACPI parsing
    interface changes, however it failed to meet requirements. More details can be
    found here: https://lkml.org/lkml/2015/9/7/285

    Lukasz Anaczkowski (2):
    acpi: Added acpi_subtable_proc to ACPI table parsers
    x86, acpi: Handle apic/x2apic entries in MADT in correct order

    arch/x86/kernel/acpi/boot.c | 22 +++++++++--
    drivers/acpi/tables.c | 89 ++++++++++++++++++++++++++++++++++++---------
    include/linux/acpi.h | 13 +++++++
    3 files changed, 103 insertions(+), 21 deletions(-)

    --
    1.8.3.1



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