Re: [PATCH] x86: allow 8 more cpus could be used

[Yinghai Lu <yinghai@kernel.org>]

Ingo Molnar wrote:
> * Randy Dunlap <randy.dunlap@oracle.com> wrote:
> 
>> Ingo Molnar wrote:
>>> * Randy Dunlap <randy.dunlap@oracle.com> wrote:
>>>
>>>> Ingo Molnar wrote:
>>>>> * Yinghai Lu <yinghai@kernel.org> wrote:
>>>>>
>>>>>> Impact: fix left out MARCO
>>>>>>
>>>>>> X86_PC will be always enabled. so need to check if we have bigsmp 
>>>>>> support built in before cut off more than 8 cpus.
>>>>> ah, that's a leftover reference to X86_PC. It can now be removed, together 
>>>>> with the Kconfig X86_PC option.
>>>>>
>>>>>> -#if defined(CONFIG_X86_PC) && defined(CONFIG_X86_32)
>>>>>> +#if defined(CONFIG_X86_PC) && !defined(CONFIG_X86_BIGSMP)
>>>>>>  	if (def_to_bigsmp && nr_cpu_ids > 8) {
>>>>>>  		unsigned int cpu;
>>>>>>  		unsigned nr;
>>>>> Could you please send a patch that removes both X86_PC and X86_BIGSMP - 
>>>>> and removes the above cutoff code too, so that it will be built-in all the 
>>>>> time?
>>>> and at what cost, please?
>>> the size difference between a bigsmp and a normal-smp x86 defconfig kernel 
>>> is 0.011%. Zero difference on a UP kernel. (And UP is what most of the 
>>> ultra-embedded systems are using)
>> That's static size?  how about cpu and apic table space?
> 
> What do you mean? What is your point and what is your exact question?
> 

it seems he still want to use mach-default direct without apic-> involoved.

YH