linux-kernel - Re: [PATCH v4 0/3] x86, apic, kexec: Add disable_cpu

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Message-ID: <20131031005812.GA15459@anatevka.fc.hp.com>
Date:	Wed, 30 Oct 2013 18:58:13 -0600
From:	jerry.hoemann@...com
To:	HATAYAMA Daisuke <d.hatayama@...fujitsu.com>
Cc:	hpa@...ux.intel.com, ebiederm@...ssion.com, vgoyal@...hat.com,
	kexec@...ts.infradead.org, linux-kernel@...r.kernel.org,
	bp@...en8.de, akpm@...ux-foundation.org, fengguang.wu@...el.com,
	jingbai.ma@...com
Subject: Re: [PATCH v4 0/3] x86, apic, kexec: Add disable_cpu_apic kernel
 parameter

On Wed, Oct 23, 2013 at 09:05:06AM +0900, HATAYAMA Daisuke wrote:
> >>
> >>- Rebased on top of v3.12-rc6
> >>
> >>- Basic design has been changed. Now users need to figure out initial
> >>   APIC ID of BSP in the 1st kernel and configures kernel parameter for
> >>   the 2nd kernel manually using disable_cpu_apic kernel parameter to
> >>   be newly introduced in this patch set. This design is more flexible
> >>   than the previous version in that we no longer have to rely on
> >>   ACPI/MP table to get initial APIC ID of BSP.
> >
> >
> >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.
> 
> HATAYAMA, Daisuke


Daisuke,

Are you planning on making changes to the kexec tools to automate
the setting of disable_cpu_apic to the capture kernel? Or do you
know someone who is planning this?

I back ported the kernel side changes to a 4.2.32 based kernel.
I tested the patch on a prototype system which exhibits a stable
initial_apic_id for CPU 0.  While not something that would be suitable
for customers, it does allow me to test the kernel portion of the patch.

I will report the results of the testing later this week.

Thanks

Jerry


-- 

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Jerry Hoemann            Software Engineer              Hewlett-Packard/MODL

3404 E Harmony Rd. MS 57                        phone:  (970) 898-1022
Ft. Collins, CO 80528                           FAX:    (970) 898-XXXX
                                                email:  jerry.hoemann@...com
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