On Fri, 17 Jul 2015 12:36:34 -0700, Guenter Roeck wrote:
> Hi Jean,
>
> On 07/17/2015 12:11 PM, Jean Delvare wrote:
>
> >
> > We could just drop NUM_REAL_CORES and use CONFIG_NR_CPUS instead, I
> > would be fine with that. This lets people worried about memory
> > consumption control it.
>
> Unfortunately this won't work because the CPU ID is non-linear;
> an 8-core system may have a CPU ID larger than 7.
Oh right, I forgot about that. Brilliant hardware/firmware engineers...
Well that does not prevent us from using CONFIG_NR_CPUS, "just" the
code would need to be modified to remove the assumption that the array
index matches the logical CPU ID.
BTW I wonder how the rest of the kernel handles the situation.
CONFIG_NR_CPUS is used where relevant so there certainly _is_ a linear
numbering which is independent from the CPU ID.
--
Jean Delvare
SUSE L3 Support
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> Hi Jean,
>
> On 07/17/2015 12:11 PM, Jean Delvare wrote:
>
> >
> > We could just drop NUM_REAL_CORES and use CONFIG_NR_CPUS instead, I
> > would be fine with that. This lets people worried about memory
> > consumption control it.
>
> Unfortunately this won't work because the CPU ID is non-linear;
> an 8-core system may have a CPU ID larger than 7.
Oh right, I forgot about that. Brilliant hardware/firmware engineers...
Well that does not prevent us from using CONFIG_NR_CPUS, "just" the
code would need to be modified to remove the assumption that the array
index matches the logical CPU ID.
BTW I wonder how the rest of the kernel handles the situation.
CONFIG_NR_CPUS is used where relevant so there certainly _is_ a linear
numbering which is independent from the CPU ID.
--
Jean Delvare
SUSE L3 Support
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/