rcu: Remove the RCU_KTHREAD_PRIO Kconfig option (f7a10a97) · Commits · 戴 / test

init/Kconfig

+0 −31

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		@@ -697,37 +697,6 @@ config RCU_BOOST
		Say Y here if you are working with real-time apps or heavy loads
		Say N here if you are unsure.

		config RCU_KTHREAD_PRIO
		int "Real-time priority to use for RCU worker threads"
		range 1 99 if RCU_BOOST
		range 0 99 if !RCU_BOOST
		default 1 if RCU_BOOST
		default 0 if !RCU_BOOST
		depends on RCU_EXPERT
		help
		This option specifies the SCHED_FIFO priority value that will be
		assigned to the rcuc/n and rcub/n threads and is also the value
		used for RCU_BOOST (if enabled). If you are working with a
		real-time application that has one or more CPU-bound threads
		running at a real-time priority level, you should set
		RCU_KTHREAD_PRIO to a priority higher than the highest-priority
		real-time CPU-bound application thread. The default RCU_KTHREAD_PRIO
		value of 1 is appropriate in the common case, which is real-time
		applications that do not have any CPU-bound threads.

		Some real-time applications might not have a single real-time
		thread that saturates a given CPU, but instead might have
		multiple real-time threads that, taken together, fully utilize
		that CPU. In this case, you should set RCU_KTHREAD_PRIO to
		a priority higher than the lowest-priority thread that is
		conspiring to prevent the CPU from running any non-real-time
		tasks. For example, if one thread at priority 10 and another
		thread at priority 5 are between themselves fully consuming
		the CPU time on a given CPU, then RCU_KTHREAD_PRIO should be
		set to priority 6 or higher.

		Specify the real-time priority, or take the default if unsure.

		config RCU_BOOST_DELAY
		int "Milliseconds to delay boosting after RCU grace-period start"
		range 0 3000

kernel/rcu/tree.c

+0 −4

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		@@ -168,11 +168,7 @@ static void rcu_report_exp_rdp(struct rcu_state *rsp,
		static void sync_sched_exp_online_cleanup(int cpu);

		/* rcuc/rcub kthread realtime priority */
		#ifdef CONFIG_RCU_KTHREAD_PRIO
		static int kthread_prio = CONFIG_RCU_KTHREAD_PRIO;
		#else /* #ifdef CONFIG_RCU_KTHREAD_PRIO */
		static int kthread_prio = IS_ENABLED(CONFIG_RCU_BOOST) ? 1 : 0;
		#endif /* #else #ifdef CONFIG_RCU_KTHREAD_PRIO */
		module_param(kthread_prio, int, 0644);

		/* Delay in jiffies for grace-period initialization delays, debug only. */

tools/testing/selftests/rcutorture/configs/rcu/TREE03

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		@@ -14,6 +14,5 @@ CONFIG_RCU_FANOUT_LEAF=2
		CONFIG_RCU_NOCB_CPU=n
		CONFIG_DEBUG_LOCK_ALLOC=n
		CONFIG_RCU_BOOST=y
		CONFIG_RCU_KTHREAD_PRIO=2
		CONFIG_DEBUG_OBJECTS_RCU_HEAD=n
		CONFIG_RCU_EXPERT=y

tools/testing/selftests/rcutorture/configs/rcu/TREE03.boot

+1 −0

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		@@ -2,3 +2,4 @@ rcutorture.onoff_interval=1 rcutorture.onoff_holdoff=30
		rcutree.gp_preinit_delay=3
		rcutree.gp_init_delay=3
		rcutree.gp_cleanup_delay=3
		rcutree.kthread_prio=2

tools/testing/selftests/rcutorture/doc/TREE_RCU-kconfig.txt

+0 −1

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		@@ -16,7 +16,6 @@ CONFIG_PROVE_LOCKING -- Do several, covering CONFIG_DEBUG_LOCK_ALLOC=y and not.
		CONFIG_PROVE_RCU -- Hardwired to CONFIG_PROVE_LOCKING.
		CONFIG_PROVE_RCU_REPEATEDLY -- Do one.
		CONFIG_RCU_BOOST -- one of PREEMPT_RCU.
		CONFIG_RCU_KTHREAD_PRIO -- set to 2 for _BOOST testing.
		CONFIG_RCU_FANOUT -- Cover hierarchy, but overlap with others.
		CONFIG_RCU_FANOUT_LEAF -- Do one non-default.
		CONFIG_RCU_FAST_NO_HZ -- Do one, but not with CONFIG_RCU_NOCB_CPU_ALL.

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