Messages in this thread | | | From | Pingfan Liu <> | Date | Wed, 6 Jun 2018 19:44:38 +0800 | Subject | Re: question about the limited interrupt vector resource on a single cpu |
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On Wed, Jun 6, 2018 at 5:34 PM, Thomas Gleixner <tglx@linutronix.de> wrote: > On Wed, 6 Jun 2018, Pingfan Liu wrote: > >> On Wed, Jun 6, 2018 at 5:15 PM, Thomas Gleixner <tglx@linutronix.de> wrote: >> > On Wed, 6 Jun 2018, Pingfan Liu wrote: >> > >> >> For x86, there is around 200 vectors left for external device on a >> >> single logic cpu. >> >> >> >> Is there any case that we exhaust them in real world, and is it worth to fix? >> > >> > Exhaustion is unlikely, but how would you fix it? The vector space per CPU >> > is limited by hardware not software. >> > >> Playing some trick on iommu, we can use it to identify the irq requester. > > But what's the point? If you have more than 200 device interrupts on a > single CPU, then you surely have other problems than that. > > What kind of problem are you trying to solve? > In kdump case, normally we set nr_cpus=1 by default, and in some huge system, it can exhaust vector space. By this is easily to resolve by inc nr_cpus. Hence I post this question to see whether there are other requirements to resolve such case
Thanks, Pingfan
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