From mboxrd@z Thu Jan  1 00:00:00 1970
From: Peter Zijlstra <peterz-wEGCiKHe2LqWVfeAwA7xHQ@public.gmane.org>
Subject: Re: CONFIG_ISOLATION=y (was: [PATCH 0/6] support "dataplane" mode
 for nohz_full)
Date: Tue, 12 May 2015 13:48:09 +0200
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To: Ingo Molnar <mingo-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
Cc: Chris Metcalf <cmetcalf-d5a29ZRxExrQT0dZR+AlfA@public.gmane.org>, Steven Rostedt <rostedt-nx8X9YLhiw1AfugRpC6u6w@public.gmane.org>, Frederic Weisbecker <fweisbec-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Andrew Morton <akpm-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org>, paulmck-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org, Gilad Ben Yossef <giladb-d5a29ZRxExrQT0dZR+AlfA@public.gmane.org>, Rik van Riel <riel-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org>, Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Thomas Gleixner <tglx-hfZtesqFncYOwBW4kG4KsQ@public.gmane.org>, Christoph Lameter <cl-vYTEC60ixJUAvxtiuMwx3w@public.gmane.org>, "Srivatsa S. Bhat" <srivatsa.bhat-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>, linux-doc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-api-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
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On Tue, May 12, 2015 at 11:10:32AM +0200, Ingo Molnar wrote:
> 
> So I'd vote for Frederic's CONFIG_ISOLATION=y, mostly because this is 
> a high level kernel feature, so it won't conflict with isolation 
> concepts in lower level subsystems such as IOMMU isolation - and other 
> higher level features like scheduler isolation are basically another 
> partial implementation we want to merge with all this...
> 

But why do we need a CONFIG flag for something that has no content?

That is, I do not see anything much; except the 'I want to stay in
userspace and kill me otherwise' flag, and I'm not sure that warrants a
CONFIG flag like this.

Other than that, its all a combination of NOHZ_FULL and cpusets/isolcpus
and whatnot.