Re: [PATCH RESEND] x86/fixup_irq: Clean the offlining CPU from theirq affinity mask

[Suresh Siddha]

On Fri, 2012-09-28 at 00:12 +0530, Srivatsa S. Bhat wrote:
> On 09/27/2012 04:16 AM, Suresh Siddha wrote:
> > 
> > No. irq_set_affinity()
> > 
> 
> Um? That takes the updated/changed affinity and sets data->affinity to
> that value no? You mentioned that probably the intention of the original
> code was to preserve the user-set affinity mask, but still change the
> underlying interrupt routing. Sorry, but I still didn't quite understand
> what is that part of the code that achieves that.

For the HW routing to be changed we AND it with cpu_online_map and use
that for programming the interrupt entries etc. The user-specified
affinity still has the cpu that is offlined.

And when the cpu comes online and if it is part of the user-specified
affinity, then the HW routing can be again modified to include the new
cpu.

hope this clears it!

thanks.

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/