Re: [PATCH] Hot swap CPU support for 2.4.1@

Would any special hardware besides a multi-cpu system be necessarey to
test this out?

Matthew Fredrickson

On Mon, Feb 05, 2001 at 03:00:40PM +1100, Rusty Russell wrote:
> Hi all,
> 
> I did the infrastructure, Anton did the bugfinding and PPC support,
> aka. the hard stuff.  Other architectures need to implement
> __cpu_disable, __cpu_die and __cpu_up for them to work.  Volunteers
> appreciated.
> 
> 	This patch allows you to down & up CPUs as follows:
> 	# echo 0 > /proc/sys/cpu/0/online
> 	# echo 1 > /proc/sys/cpu/0/online
> 
> The relatively trivial patch works as follows:
> 
> 1) Implements synchronize_kernel() (thanks Andi Kleen for forwarding
>    Paul McKenney's quiescent-state ideas) which waits for a schedule
>    on all CPUs.
> 2) All CPU numbers are now physical: removes cpu_number_map,
>    cpu_logical_map and smp_num_cpus.
> 3) Adds cpu_online(cpu) and cpu_num_online() macros.
> 4) Adds cpu_down() and cpu_up() calls, which call arch-specific
>    __cpu_disable(cpu), __cpu_die(cpu) and __cpu_up(cpu).
> 5) Fixes schedule() to check allowed_cpus even if rescheduling same
>    task.
> 
> Since it's 60k long, mime attached bzip2.
> 
> Go hack!
> Rusty Russell & Anton Blanchard
> --