On Mon, 2015-03-02 at 09:35 -0500, Rik van Riel wrote:

On 03/02/2015 07:44 AM, Mike Galbraith wrote:

quoted

On Mon, 2015-03-02 at 10:09 +0100, Peter Zijlstra wrote:

quoted

On Thu, Feb 26, 2015 at 12:12:31PM -0500, Rik van Riel wrote:

quoted

Subject: cpusets,isolcpus: add file to show isolated cpus in cpuset

The previous patch makes it so the code skips over isolcpus when
building scheduler load balancing domains. This makes it hard to
see for a user which of the CPUs in a cpuset are participating in
load balancing, and which ones are isolated cpus.

Add a cpuset.isolcpus file with info on which cpus in a cpuset are
isolated CPUs.

This file is read-only for now. In the future we could extend things
so isolcpus can be changed at run time, for the root (system wide)
cpuset only.

Acked-by: David Rientjes <redacted>
Cc: Peter Zijlstra <redacted>
Cc: Clark Williams <redacted>
Cc: Li Zefan <redacted>
Cc: Ingo Molnar <redacted>
Cc: Luiz Capitulino <redacted>
Cc: David Rientjes <redacted>
Cc: Mike Galbraith <redacted>
Cc: cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Signed-off-by: Rik van Riel <redacted>

So let me start off by saying I hate isolcpus ;-)

Let me further state that I had hopes we could extend cpusets to
natively provide the functionality isolcpus has, and kill isolcpus.

+1

That's where nohz_full goop belongs too.

Except nohz_full and isolcpus are very much global attributes of
each CPU, so I am not sure whether it would make sense to allow
configuration of this attribute anywhere other than the root
cpuset.

They're attributes of exclusive sets, which excludes the root set.  It'd
be kinda hard to have the root set be both ticked and tickless :)

	-Mike