Messages in this thread | | | Date | Wed, 23 Oct 2013 11:51:27 -0400 | From | Vivek Goyal <> | Subject | Re: [PATCH v4 0/3] x86, apic, kexec: Add disable_cpu_apic kernel parameter |
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On Wed, Oct 23, 2013 at 09:05:06AM +0900, HATAYAMA Daisuke wrote:
[..] > >Do you literally mean a human at each boot will have to configure > >the kdump configuration files for passing disable_cpu_apic? > >Or do you envision the setting of disable_cpu_apic being put into > >the kdump initialization scripts? > > > >thanks > > > >Jerry > > Nearer to the former case, but this is not what a human should do. It's > a cumbersome task. I think, on fedora/RHEL system for example, kdump > service should check at each boot automatically.
Hi Hatayama,
So what information should I look for to prepare disable_cpu_apic=X in kdump script?
Is BSP processor info exported to user space somewhere? Or assuming that processor 0 is BSP and corresponding apicid should be disabled in kdump kernel is good enough?
I am looking at /proc/cpuinfo and following 3 fields seem interesting.
processor: 0 apicid : 0 initial apicid : 0
What's the difference between apicid and "initial apicid". I guess initial apicid reflects the apicid number as set by firmware and then kernel can overwrite it and new number would be reflected in "apicid"?
If that's the case, then I guess we should be looking at "apicid" of processor "0" and set that in disable_cpu_apic? Because that's the number kdump kernel boot should see in apic upon boot.
Thanks Vivek
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