Re: [PATCH 2/2] x86_64 irq: Only look at per_cpu data for online cpus.

[Muli Ben-Yehuda]

On Sun, Oct 22, 2006 at 10:35:34PM -0600, Eric W. Biederman wrote:
> 
> When I generalized __assign_irq_vector I failed to pay attention
> to what happens when you access a per cpu data structure for
> a cpu that is not online.   It is an undefined case making any
> code that does it have undefined behavior as well.
> 
> The code still needs to be able to allocate a vector across cpus
> that are not online to properly handle combinations like lowest
> priority interrupt delivery and cpu_hotplug.  Not that we can do
> that today but the infrastructure shouldn't prevent it.
> 
> So this patch updates the places where we touch per cpu data
> to only touch online cpus, it makes cpu vector allocation
> an atomic operation with respect to cpu hotplug, and it updates
> the cpu start code to properly initialize vector_irq so we
> don't have inconsistencies.
> 
> Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>

I tried 1/2 and 2/2 at the same time and it booted, so good work :-)
I'm stressing the machine a little now, will let you know if anything
out of the ordinary comes up.

Acked-by: Muli Ben-Yehuda <muli@xxxxxxxxxx>

Cheers,
Muli

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