Messages in this thread |  | | From | Thomas Gleixner <> | | Subject | Re: [PATCH RESEND] x86/cpu/topology: remove limit of CPUs due to noapic on x86_64 | | Date | Sun, 01 Dec 2024 14:49:32 +0100 |
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On Mon, Nov 25 2024 at 16:13, Fernando F. Mancera wrote: > On 25/11/2024 09:37, Ingo Molnar wrote: >> So what's the motivation? Arguably the x86-64 boot option behavior was >> weird: a working local APIC is very much needed to have an SMP system. >> > > Sorry if I am wrong here but I am not an expert on the matter. I > believed that "noapic" disables I/O APIC which handles external > interrupts while the local APICs are still enabled as they are managed > by "nolapic". If that is the case, SMP should still be possible. > > If both I/O APIC and Local APICs are disabled then the kernel should > fallback to a single CPU mode. That is the behavior that kernel has with > my patch. > > The motivation is to fix multiple users with systems that requires > "noapic" to work and after the rework their systems are using a single CPU.
Sorry, my bad. I messed up the "noapic" option handling.
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