rcu: Make RCU able to tolerate undefined CONFIG_RCU_KTHREAD_PRIO (26730f55) · Commits · 戴 / test

This commit updates the initialization of the kthread_prio boot parameter so that RCU will build even when CONFIG_RCU_KTHREAD_PRIO is undefined. The kthread_prio boot parameter is set to CONFIG_RCU_KTHREAD_PRIO if that is defined, otherwise to 1 if CONFIG_RCU_BOOST is defined and to zero otherwise. This commit then makes CONFIG_RCU_KTHREAD_PRIO depend on CONFIG_RCU_EXPERT, so that Kconfig users won't be asked about CONFIG_RCU_KTHREAD_PRIO unless they want to be. Reported-by:

Linus Torvalds <torvalds@linux-foundation.org> Reported-by:

Ingo Molnar <mingo@kernel.org> Signed-off-by:

Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by:

Pranith Kumar <bobby.prani@gmail.com>

init/Kconfig

+1 −0

Original line number	Diff line number	Diff line
		@@ -671,6 +671,7 @@ config RCU_KTHREAD_PRIO
		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

kernel/rcu/tree.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -165,7 +165,11 @@ static void invoke_rcu_core(void);
		static void invoke_rcu_callbacks(struct rcu_state rsp, struct rcu_data rdp);

		/* 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. */

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