Messages in this thread |  | | From | "Rafael J. Wysocki" <> | Subject | Re: [PATCH v4 0/2] Fix how CPUs are enumerated when there's more than 255 CPUs | Date | Sat, 19 Sep 2015 00:38:40 +0200 |
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On Wednesday, September 09, 2015 10:45:48 PM Rafael J. Wysocki wrote: > On Wednesday, September 09, 2015 03:47:27 PM Lukasz Anaczkowski wrote: > > 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(-) > > OK > > Does anyone in the CC have any objections against merging this series? > > If not, I'll queue it up as 4.3-rc material.
Well, I had a plan to push this for 4.3-rc2, but then I looked at it again and realized that I'd like it to stay in linux-next for a couple of weeks at least as I'm really unsure that it's not going to uncover some nastiness somewhere.
Which practically means it's now scheduled for v4.4.
Thanks, Rafael
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