doc: Add rcutree.kthread_prio pointer to stallwarn.txt (0500873d) · Commits · 戴 / test

This commit adds mention of the rcutree.kthread_prio kernel boot parameter to the discussion of how high-priority real-time tasks can result in RCU CPU stall warnings. (However, this does not necessarily help when the high-priority real-time tasks are using dubious deadlines.) Signed-off-by:

Paul E. McKenney <paulmck@linux.ibm.com>

Documentation/RCU/stallwarn.txt

+6 −0

Original line number	Diff line number	Diff line
		@@ -57,6 +57,12 @@ o A CPU-bound real-time task in a CONFIG_PREEMPT_RT kernel that
		CONFIG_PREEMPT_RCU case, you might see stall-warning
		messages.

		You can use the rcutree.kthread_prio kernel boot parameter to
		increase the scheduling priority of RCU's kthreads, which can
		help avoid this problem. However, please note that doing this
		can increase your system's context-switch rate and thus degrade
		performance.

		o A periodic interrupt whose handler takes longer than the time
		interval between successive pairs of interrupts. This can
		prevent RCU's kthreads and softirq handlers from running.

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