Re: [Xen-devel] [PATCH V2] acpi: enlarge NUM_FIXMAP_ACPI_PAGES to support larger scale boards

["Zhangbo (Oscar)" <oscar.zhangbo@xxxxxxxxxx>]

>
>>
>> Thus, we make NUM_FIXMAP_ACPI_PAGES much larger, to 64(256KB). it's
>> calculated for that the theoretical largest CPU number on main Linux
>> distros is about 8092, and memory slots number should be within 1000,
>> that's 24B*8092+40B*1000 = 234208B. Meanwhile, because
>IOREMAP_VIRT_*
>> region is 16GB, thus I think extending it to 256KB is safe enough.
>>
>> Of course, there's much more work to do to support large scale boards of
>> that many(8092) CPUs and 1000 memory slots. We just make life easier for
>> boards with serveral hundreds of CPUs and serveral TBs of memory.
>>
>> Signed-off-by: Zhang Bo <oscar.zhangbo@xxxxxxxxxx>
>
>Much better, but how did you arrive at 8092? Did you mean 8192
>(2**13)? Also I don't think the table entry fields should be listed,
>stating their size is good enough (if anyone cares to check the
>sizes are correct, (s)he'd need to go look at the spec or some
>header anyway). I'd be fine with adjusting the commit message
>accordingly while committing. With such adjustments
>

Thanks, Jan!
Yes, that's 8192 :) 
The sites I referenced are:
https://www.suse.com/products/server/technical-information/#Kernel (8192)
https://access.redhat.com/articles/rhel-limits (5120)

>Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
>
>You didn't Cc Julien, so I assume (and agree) that this is rather
>meant for post-4.9. Whether to backport we can decide later.
>
>Jan


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