Messages in this thread | | | Date | Thu, 19 Dec 2013 13:11:32 -0500 | From | Prarit Bhargava <> | Subject | Re: [PATCH] x86: Add check for number of available vectors before CPU down [v2] |
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On 12/19/2013 01:05 PM, Tony Luck wrote: > On Wed, Dec 18, 2013 at 11:50 AM, Tony Luck <tony.luck@intel.com> wrote: >> Looks good to me. > > Though now I've been confused by an offline question about affinity.
Heh :) I'm pursuing it now. Rui has asked a pretty good question that I don't know the answer to off the top of my head. I'm still looking at the code.
> > Suppose we have some interrupt that has affinity to multiple cpus. E.g. > (real example from one of my machines): > > # cat /proc/irq/94/smp_affinity_list > 26,54 > > Now If I want to take either cpu26 or cpu54 offline - I'm guessing that I don't > really need to find a new home for vector 94 - because the other one of that > pair already has that set up. But your check_vectors code doesn't look like > it accounts for that - if we take cpu26 offline - it would see that > cpu54 doesn't > have 94 free - but doesn't check that it is for the same interrupt. > > But I may be mixing "vectors" and "irqs" here.
Yep. The question really is this: is the irq mapped to a single vector or multiple vectors. (I think)
P.
> > -Tony
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