Messages in this thread | | | Date | Wed, 30 Sep 2015 19:43:23 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH RFC] x86: Reduce MAX_LOCAL_APIC and MAX_IO_APICS |
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On Wed, 30 Sep 2015, Denys Vlasenko wrote: > On 09/30/2015 05:11 PM, Thomas Gleixner wrote: > > On Fri, 25 Sep 2015, Denys Vlasenko wrote: > >> > >> +config MAX_LAPIC_ID > >> + int "Maximum APIC ID" > >> + range 8 32768 > >> + default "8" > >> + ---help--- > >> + Use this option to set maximum allowed Local APIC ID higher than > >> + maximum number of CPUs. This may be necessary for machines > >> + with large number of processor sockets and non-contiguous > >> + LAPIC numbering. > >> + This setting will be automatically rounded up, if necessary. > > > > This is wrong. If you would limit the APIC IDs then you really break > > stuff. You can only limit the number of APICs. > > This CONFIG setting allows to _increase_ max APIC ID.
NO. This is crap. I don't want to tweak a gazillion of knobs just to build a kernel with CONFIG_NR_CPUS=8. Really not.
If you really want to make that space saving, then make it a runtime allocation.
Thanks,
tglx
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