Re: [PATCH sched-devel 0/7] CPU isolation extensions

From: Max Krasnyanskiy
Date: Fri Feb 22 2008 - 16:05:00 EST


Dmitry Adamushko wrote:
Hi Max,

[ ... ]
Last patch to the stop machine is potentially unsafe and is marked as experimental. Unfortunately
it's currently the only option that allows dynamic module insertion/removal for above scenarios.

I'm puzzled by the following part (can be a misunderstanding from my side)

+config CPUISOL_STOPMACHINE
+ bool "Do not halt isolated CPUs with Stop Machine (EXPERIMENTAL)"
+ depends on CPUISOL && STOP_MACHINE && EXPERIMENTAL
+ help
+ If this option is enabled kernel will not halt isolated CPUs
+ when Stop Machine is triggered. Stop Machine is currently only
+ used by the module insertion and removal.

this "only" part. What about e.g. a 'cpu hotplug' case (_cpu_down())?
(or we should abstract it a bit to the point that e.g. a cpu can be
considered as 'a module'? :-)

My bad. I forgot to update that text. As you and other folks pointed out
stopmachine is used in a few other places besides module loading. We had a discussion about this awhile ago. I just forgot to update the text. Will do.

Max
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