[PATCH v4 1/3] x86, apic: Don't count the CPU with BP flag from MP table as booting-up CPU
vgoyal at redhat.com
Mon Nov 11 11:52:03 EST 2013
On Mon, Nov 11, 2013 at 11:52:30AM +0900, HATAYAMA Daisuke wrote:
> Looking at my past investigation, kernel/mpparse.c, mm/amdtopology.c and
> platform/visws/visws_quirks.c assumes that boot_cpu_physical_apicid
> has initial apicid of the BSP, not the current actual booting-up cpu.
> These three are called in get_smp_config() below. If either of them is
> called actually, boot_cpu_physical_apicid has the apicid different from
> the current actual booting-up cpu temporarily. But init_apic_mappings()
> soon modifies back the value to the one obtained by read_apic_id().
> * Read APIC and some other early information from ACPI tables.
> * get boot-time SMP configuration:
> if (smp_found_config)
> So, thanks to init_apic_mappings(), the patch set would work without the
> first patch... This is a careless point in this patch set.
If init_apic_mappings(), is making sure that boot_cpu_physical_apicid is
apic id of booting processor, and you don't need first patch of your
series, then I think atleast re-post your patch series without first
And then there can be another series which looks into whether we need
two different variables or not and if we do, then a separate variable
bsp_physical_apicid will track the bsp id as reported by BIOS and
boot_cpu_physical_apicid will track apic id of booting cpu. This might
a very big and slow cleanup. So I think blocking the first patch series
behind it might not make much sense.
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