Re: [RFC PATCH]: ACPI: Automatically online hot-added memory

[Thomas Renninger <trenn@suse.de>]

On Thursday 11 March 2010 09:32:09 chen gong wrote:
> On 2010-3-11 16:07, ykzhao wrote:
... 
> BTW, how about using UDEV rules to do this operation. It looks more smooth. I know some
> Novell guy is working on it.
I also know this guy :)

These would be the udev rules to automatically add memory/cpus:
SUBSYSTEM=="cpu", ACTION=="add", TEST=="online", ATTR{online}=="0", ATTR{online}="1", RUN+="/bin/logger onlining cpu: $env{DEVPATH}"
SUBSYSTEM=="memory", ACTION=="add", TEST=="state", ATTR{state}=="offline", ATTR{state}="online", RUN+="/bin/logger onlining memory: $env{DEVPATH}"

But this should be the same as you suggest (at least the memory rule)
to do in the kernel:
automatically online the memory, once hotadded.

I would not add any udev rules before this does not work
reliably and currently it is totally broken, mainly because:
  - not being able to alloc memory on foreign nodes (at least with slab)
  - C-state, throttling and cpufreq set up is done without valid
    cpu_data(new_cpu) resulting in wrong C-state (and other) info

   Thomas