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 | 91 ++++++++++++++++++++++++++++++++++++--------- include/linux/acpi.h | 19 ++++++++-- 3 files changed, 107 insertions(+), 25 deletions(-) -- 1.8.3.1 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
