*** Bug 1442230 has been marked as a duplicate of this bug. ***

Fixed by following upstream commit:
https://github.com/redhat-performance/tuned/commit/af56ac35ed839846a475b048d8e982d81bbde6c4

tuned-2.9.0-0.1.rc1.fc26 has been submitted as an update to Fedora 26. https://bodhi.fedoraproject.org/updates/FEDORA-2017-d9c6b990df

tuned-2.9.0-0.1.rc1.fc26 has been pushed to the Fedora 26 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2017-d9c6b990df

tuned-2.9.0-0.1.rc1.fc27 has been pushed to the Fedora 27 testing repository. If problems still persist, please make note of it in this bug report.
See https://fedoraproject.org/wiki/QA:Updates_Testing for
instructions on how to install test updates.
You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2017-5f0849d207

tuned-2.9.0-1.fc27 has been submitted as an update to Fedora 27. https://bodhi.fedoraproject.org/updates/FEDORA-2017-0e45ce4685

tuned-2.9.0-1.fc26 has been submitted as an update to Fedora 26. https://bodhi.fedoraproject.org/updates/FEDORA-2017-c30e9bd1ea

Tested by automated test case /CoreOS/tuned/Regression/whitelist-of-processes-which-should-not-be-repined-on-isolated-cores

======================================================
Verified in:
    tuned-2.9.0-1.el7.noarch
    tuned-profiles-cpu-partitioning-2.9.0-1.el7.noarch
PASS
======================================================

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
::   Test cpu-partitioning
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

:: [   PASS   ] :: Command './pmd &' (Expected 0, got 0)
:: [   LOG    ] :: There is assumption that cpu affinity mask contains value 'f+'.
:: [   PASS   ] :: Check CPU Affinity of process number 1 (Expected 0, got 0)
:: [   PASS   ] :: Check CPU Affinity of pmd process (Expected 0, got 0)
:: [   PASS   ] :: Command 'echo 'isolated_cores=2-4' > /etc/tuned/cpu-partitioning-variables.conf' (Expected 0, got 0)
:: [   PASS   ] :: Command 'tuned-adm profile cpu-partitioning' (Expected 0, got 0)
:: [   PASS   ] :: Check CPU Affinity of process number 1 after test profile is loaded (should be new value, not only f+) (Expected 0, got 0)
:: [   PASS   ] :: Check CPU Affinity of pmd process (should be old f+ value) (Expected 0, got 0)

======================================================
Reproduced in:
    tuned-2.8.0-5.el7.noarch
    tuned-profiles-cpu-partitioning-2.8.0-5.el7.noarch
FAIL
======================================================

::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
:: [   LOG    ] :: Test cpu-partitioning
::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::

:: [   PASS   ] :: Command './pmd &' (Expected 0, got 0)
:: [   LOG    ] :: There is assumption that cpu affinity mask contains value 'f+'.
:: [   PASS   ] :: Check CPU Affinity of process number 1 (Expected 0, got 0)
:: [   PASS   ] :: Check CPU Affinity of pmd process (Expected 0, got 0)
:: [   PASS   ] :: Command 'echo 'isolated_cores=2-4' > /etc/tuned/cpu-partitioning-variables.conf' (Expected 0, got 0)
:: [   PASS   ] :: Command 'tuned-adm profile cpu-partitioning' (Expected 0, got 0)
:: [   PASS   ] :: Check CPU Affinity of process number 1 after test profile is loaded (should be new value, not only f+) (Expected 0, got 0)
:: [   FAIL   ] :: Check CPU Affinity of pmd process (should be old f+ value) (Expected 0, got 1)

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://access.redhat.com/errata/RHBA-2018:0879