Re: [PATCH V3 0/4] genirq/affinity: irq vector spread among online CPUs as far as possible

[Artem Bityutskiy <dedekind1@gmail.com>]

On Thu, 2018-03-08 at 18:53 +0800, Ming Lei wrote:
> Hi,
> 
> This patchset tries to spread among online CPUs as far as possible, so
> that we can avoid to allocate too less irq vectors with online CPUs
> mapped.
> 
> For example, in a 8cores system, 4 cpu cores(4~7) are offline/non present,
> on a device with 4 queues:
> 
> 1) before this patchset
> 	irq 39, cpu list 0-2
> 	irq 40, cpu list 3-4,6
> 	irq 41, cpu list 5
> 	irq 42, cpu list 7
> 
> 2) after this patchset
> 	irq 39, cpu list 0,4
> 	irq 40, cpu list 1,6
> 	irq 41, cpu list 2,5
> 	irq 42, cpu list 3,7
> 
> Without this patchset, only two vectors(39, 40) can be active, but there
> can be 4 active irq vectors after applying this patchset.

Tested-by: Artem Bityutskiy <artem.bityutskiy@intel.com>
Link: https://lkml.kernel.org/r/1519311270.2535.53.camel@intel.com

Ming,

this patchset fixes the v4.16-rcX regression that I reported few weeks
ago. I applied it and verified that Dell R640 server that I mentioned
in the bug report boots up and the disk works.

So this is not just an improvement, it also includes a bugfix. 

Thanks!