RE: [PATCH]send slave cpus to SAL slave loop on crash (IA64)

From: Zou, Nanhai <nanhai.zou_at_intel.com>
Date: 2006-10-31 15:33:33
> -----Original Message-----
> From: Jay Lan [mailto:jlan@sgi.com]
> Sent: 20061031 10:53
> To: Zou, Nanhai
> Cc: fastboot; Linux-IA64; Jack Steiner; Luck, Tony
> Subject: Re: [PATCH]send slave cpus to SAL slave loop on crash (IA64)
> 
> Zou, Nanhai wrote:
> >> -----Original Message-----
> >> From: Jay Lan [mailto:jlan@engr.sgi.com]
> >> Sent: 2006A"10O^A^31E`O~ 4:36
> >> To: fastboot
> >> Cc: Linux-IA64; Zou, Nanhai; Jack Steiner; Luck, Tony
> >> Subject: [PATCH]send slave cpus to SAL slave loop on crash (IA64)
> >>
> >> This patch is to fix a problem of interrupts being sent to cpus
> >> that can not respond.
> >>
> >> This patch would return slave cpus to SAL slave loop, at time of
> >> crash, except cpu0. The cpu0 is a special case as there is no way
> >> to return it to SAL, so cpu0 is better handled in firmware.
> >>
> >> Signed-off-by: Jay Lan <jlan@sgi.com>
> >>
> >
> >
> > Does this fix the I/O interrupt redirect issue on SN?
> 
> This fixes the interrupts being sent to cpus not in the
> slave loop that caused hang on SN. When one boots up the
> kexec'ed kernel with 'maxcpus=1', all idle cpus needs to
> be sent back. If they are not returned to the SAL slave
> loop and just looping in cpu_relax(), they are considered
> alive, but interrupts would be lost and system hang.
> 

 But this will rely on machine crash on CPU 0?
 Current Kdump will boot to second kernel on the crashing CPU. 
 So if machine crash and boot on CPU N, CPU 0 will still not be able to redirect interrupt, right?  

> This is different from the kexec '--noio' option you added
> to kexec-tools. We still need that fix.
> 


 Does --noio patch works on SN? I remember you have mentioned there is still some issue when you testing --noio option on SN system?

> > However this patch will make Kdump depends on cpu hotplug code, so you may
> add the dependency in Kconfig.
> 
> I thought Kahalid Aziz's patch covered this?
> http://lists.osdl.org/mailman/htdig/fastboot/2006-October/004548.html
> 

> Thanks,
>  - jay
> 
> >
> > Thanks
> > Zou Nan hai
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Received on Tue Oct 31 15:33:44 2006

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