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Subject: Re: [PATCH v2] isolcpus: affine kernel threads to specified cpumask
To:     Frederic Weisbecker <frederic@kernel.org>,
        David Laight <David.Laight@ACULAB.COM>
Cc:     'Marcelo Tosatti' <mtosatti@redhat.com>,
        Thomas Gleixner <tglx@linutronix.de>,
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        Christoph Lameter <cl@linux.com>,
        Jim Somerville <Jim.Somerville@windriver.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Frederic Weisbecker <fweisbec@gmail.com>,
        Peter Zijlstra <peterz@infradead.org>
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From:   Chris Friesen <chris.friesen@windriver.com>
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Date:   Thu, 26 Mar 2020 10:32:51 -0600
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On 3/26/2020 10:22 AM, Frederic Weisbecker wrote:
> On Wed, Mar 25, 2020 at 06:05:27PM +0000, David Laight wrote:

>> How about making it possible to change the default affinity
>> for new kthreads at run time?
>> Is it possible to change the affinity of existing threads?
>> Or maybe only those that didn't specify an explicit one??
> 
> That's already possible yes, most unbound kthreads are accessible
> through /proc including kthreadd from which new kthread will inherit
> their CPU affinity.

Are you sure that the new kthread will inherit the CPU affinity?

__kthread_create_on_node() explicitly sets the new thread as 
SCHED_NORMAL with a mask of "cpu_all_mask".

Chris