Re: [PATCH v12 05/13] task_isolation: support CONFIG_TASK_ISOLATION_ALL

[Chris Metcalf]

On 5/18/2016 9:35 AM, Peter Zijlstra wrote:
> On Tue, Apr 05, 2016 at 01:38:34PM -0400, Chris Metcalf wrote:
> > This option, similar to NO_HZ_FULL_ALL, simplifies configuring
> > a system to boot by default with all cores except the boot core
> > running in task isolation mode.
> Hurm, we still have that option? I thought we killed it, because random
> people set it and 'complain' their system misbehaves.

It's still in, as of 4.6 (and still in linux-next too).  I did receive
feedback saying the option was useful, when setting up a kernel to run
isolation apps on systems that may have a varying number of processsors,
since it means you don't need to tweak the boot arguments each time.

A different approach that I'd be happy to pursue would be to provide
a "clipping" version of cpulist_parse() that allows you to pass a boot
argument like "nohz_full=1-1000" and just clip off the impossible cpus.
We could then change "nohz_full=" and "task_isolation=" to use it.

--
Chris Metcalf, Mellanox Technologies
http://www.mellanox.com