From: Joel Fernandes <joelagnelf@nvidia.com>
To: paulmck@kernel.org, rcu@vger.kernel.org, linux-kernel@vger.kernel.org
Cc: Sebastian Andrzej Siewior <bigeasy@linutronix.de>,
Frederic Weisbecker <frederic@kernel.org>,
Neeraj Upadhyay <neeraj.upadhyay@kernel.org>,
Boqun Feng <boqun@kernel.org>,
Joel Fernandes <joelagnelf@nvidia.com>,
Josh Triplett <josh@joshtriplett.org>,
Uladzislau Rezki <urezki@gmail.com>,
Steven Rostedt <rostedt@goodmis.org>,
Mathieu Desnoyers <mathieu.desnoyers@efficios.com>,
Lai Jiangshan <jiangshanlai@gmail.com>,
Zqiang <qiang.zhang@linux.dev>,
Davidlohr Bueso <dave@stgolabs.net>,
Jonathan Corbet <corbet@lwn.net>,
Shuah Khan <skhan@linuxfoundation.org>,
linux-doc@vger.kernel.org, linux-kselftest@vger.kernel.org
Subject: [PATCH RFC 7/7] rcutorture: Make BUSTED-BOOST disable RCU priority boosting
Date: Wed, 11 Nov 2026 16:38:25 -0500 [thread overview]
Message-ID: <20261111213826.2035045-8-joelagnelf@nvidia.com> (raw)
In-Reply-To: <20261111213826.2035045-1-joelagnelf@nvidia.com>
BUSTED-BOOST is supposed to fail because priority boosting is broken,
but boosting is now always built in for preemptible RCU, so the
scenario passed. Boot it with rcutree.boost_disable=1 so that it again
exercises rcutorture's ability to detect missing priority boosting.
Testing: kvm.sh --configs BUSTED-BOOST --duration 10 now ends FAILURE,
with 81 of 84 boost intervals reporting:
rcu_torture_boost boosting failed
Boost inversion: reader got only 203 of 2000 ms CPU in 4003 jiffies
Without the parameter the same scenario passed with no boost failures.
Signed-off-by: Joel Fernandes <joelagnelf@nvidia.com>
---
tools/testing/selftests/rcutorture/configs/rcu/BUSTED-BOOST.boot | 1 +
1 file changed, 1 insertion(+)
diff --git a/tools/testing/selftests/rcutorture/configs/rcu/BUSTED-BOOST.boot b/tools/testing/selftests/rcutorture/configs/rcu/BUSTED-BOOST.boot
index 84f6bb98ce99..5aa92357958a 100644
--- a/tools/testing/selftests/rcutorture/configs/rcu/BUSTED-BOOST.boot
+++ b/tools/testing/selftests/rcutorture/configs/rcu/BUSTED-BOOST.boot
@@ -6,3 +6,4 @@ rcutree.gp_cleanup_delay=3
rcutree.kthread_prio=2
threadirqs
rcutree.use_softirq=0
+rcutree.boost_disable=1
--
2.54.0
prev parent reply other threads:[~2026-11-11 21:38 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-11-11 21:38 [PATCH RFC 0/7] rcutorture: Rewrite RCU priority-boost test around a CPU-hungry reader Joel Fernandes
2026-11-11 21:38 ` [PATCH RFC 1/7] " Joel Fernandes
2026-11-11 21:38 ` [PATCH RFC 2/7] rcutorture: Stop disabling RT throttling for boost testing Joel Fernandes
2026-11-11 21:38 ` [PATCH RFC 3/7] rcutorture: Remove unused check_boost_failed hook Joel Fernandes
2026-11-11 21:38 ` [PATCH RFC 4/7] doc: Document rcutorture.test_boost_reader_ms Joel Fernandes
2026-11-11 21:38 ` [PATCH RFC 5/7] rcu: Add rcutree.boost_disable to disable priority boosting at runtime Joel Fernandes
2026-11-11 21:38 ` [PATCH RFC 6/7] doc: Document rcutree.boost_disable Joel Fernandes
2026-11-11 21:38 ` Joel Fernandes [this message]
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