Re: [PATCH] kexec for ia64

From: Khalid Aziz <khalid_aziz_at_hp.com>
Date: 2006-03-15 03:00:15
On Mon, 2006-03-13 at 22:44 -0800, Andrew Morton wrote:
> Khalid Aziz <khalid_aziz@hp.com> wrote:
> > +	int cpu;
> > +
> > +	for_each_online_cpu(cpu) {
> > +		if (cpu != smp_processor_id())
> > +			cpu_down(cpu);
> > +	}
> > +#else
> > +	smp_call_function(kexec_stop_this_cpu, (void *)image->start, 0, 0);
> > +#endif
> > +#endif
> 
> Why is different code needed for hotplug cpu?

Hi Andrew,

It is preferable to use cpu_down() to shoot down a cpu, but this
function is available only with CONFIG_HOTPLUG_CPU. If
CONFIG_HOTPLUG_CPU is not enabled, only other way to shut down slave
CPUs in a state where they would come back up when the new kernel boots
up and sends them IPI is to hold them in a fake rendezvous which is what
the function kexec_stop_this_cpu() does. So the choices are either to
keep both ways of shutting down CPUs or go with kexec_stop_this_cpu()
for all cases.

Thanks for the comments. I will move declarations to header files as you
suggested.

-- 
Khalid

====================================================================
Khalid Aziz                       Open Source and Linux Organization
(970)898-9214                                        Hewlett-Packard
khalid.aziz@hp.com                                  Fort Collins, CO

"The Linux kernel is subject to relentless development" 
                                - Alessandro Rubini


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Received on Wed Mar 15 03:00:55 2006

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