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From: | Almudena Garcia |
Subject: | Re: [PATCH] SMP initialization: detection and enumeration |
Date: | Tue, 11 Aug 2020 23:03:55 +0200 |
> So don't bring them online then? The user asked for 4 CPUs, so bring up> 3 APs alongside the BSP and that's that.It's not a bad idea. Then I will fix my cpu enumeration loop to add this new condition.
El mar., 11 ago. 2020 a las 2:23, Jessica Clarke (<jrtc27@jrtc27.com>) escribió:On 11 Aug 2020, at 01:17, Almudena Garcia <liberamenso10000@gmail.com> wrote:
>
> > That being said, instead of hardcoding the maximum number of CPUs to
> > be 256, you can just let the user choose whatever value is preferred.
> > That's what Linux does.
>
> But this could cause coherency problems.
Coherency is a very specific thing in operating systems about the
properties of the underlying memory subsystem. It's not the word you're
looking for.
> By example, if the user sets mach_ncpus=4 , and the processor has 8 cores, It can produce an out-of-index error in the access to the arrays which store the info about the cpus.
So don't bring them online then? The user asked for 4 CPUs, so bring up
3 APs alongside the BSP and that's that.
Jess
0001-smp-Add-pseudoclass-to-manage-APIC-operations.patch
Description: Text Data
0002-vm_kern-Add-kmem_alloc_aligned_table.patch
Description: Text Data
0003-smp-Add-APIC-finder-and-parser.patch
Description: Text Data
0004-smp-Add-generic-smp-pseudoclass.patch
Description: Text Data
0005-model_dep.c-Add-smp_init-call.patch
Description: Text Data
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