Re: [rfc] fix Kconfig, hotplug_cpu is needed for swsusp

[Pavel Machek]

Hi!

> here is an attempt to explain why...
> 
> > 
> > Something which remains to be beaten into my head: *why* does HOTPLUG_CPU
> > require flat pyhsical mode?  What necessitated that change, and cannot we
> > make it work OK in logical mode as well as flat mode?
> 
> Short answer
> 
> 1. Will hotplug work today in logical flat mode without selecting bigsmp?
> 
>    	Yes, since we avoid broadcast on i386 IPI's with no_broadcast option.
> 
> 2. Why use bigsmp then?
>    There is no reason to do the same thing in two different ways. i.e using
>    logical flat with no_broadcast=1, or use the bigsmp by default when hotplug cpu is
>    enabled. IOW we wanted the handling consistent with what we do for x86_64, hence the 
>    decision to use bigsmp automatically when hotplug is enabled or
> we notice >8 CPUS.

Why not make it even more consistent and just use bigsmp mode by
default, even for X86_PC? X86_BIGSMP would be reduntant, then...
									Pavel

-- 
Picture of sleeping (Linux) penguin wanted...
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/