Re: [patch 10/20] cpu/hotplug: Make target state writeable

From: Rafael J. Wysocki
Date: Fri Feb 26 2016 - 18:44:48 EST

Hi Thomas,

On Friday, February 26, 2016 06:43:32 PM Thomas Gleixner wrote:
> Make it possible to write a target state to the per cpu state file, so we can
> switch between states.

One thing that potentially may be problematic here is that any kind of
"offline" operations needs to be carried out under device_hotplug_lock,
because there are cases in which devices (including CPUs) are taken
offline in groups and if one offline fails, the whole operation has to
be rolled back.

So if you put a CPU into one of the intermediate states manually and
something like the above happens in parallel with it, they may not
play well together IMO.