rcu: Parameterize rcu_check_gp_start_stall() (791416c4) · Commits · 戴 / test

In order to debug forward-progress stalls, it is necessary to check for excessively delayed grace-period starts. This is currently done for RCU CPU stall warnings by rcu_check_gp_start_stall(), which checks to see if the start of a requested grace period has been delayed by an RCU CPU stall warning period. Because rcutorture will need to check for the time consumed by an RCU forward-progress delay, this commit promotes gpssdelay from a local variable to a formal parameter. It is not necessary to export rcu_check_gp_start_stall() because rcutorture will access it via a wrapper function. Signed-off-by:

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

kernel/rcu/tree.c

+4 −4

Original line number	Diff line number	Diff line
		@@ -2600,10 +2600,10 @@ static void force_quiescent_state(void)
		* This function checks for grace-period requests that fail to motivate
		* RCU to come out of its idle mode.
		*/
		static void
		rcu_check_gp_start_stall(struct rcu_node rnp, struct rcu_data rdp)
		void
		rcu_check_gp_start_stall(struct rcu_node rnp, struct rcu_data rdp,
		const unsigned long gpssdelay)
		{
		const unsigned long gpssdelay = rcu_jiffies_till_stall_check();
		unsigned long flags;
		unsigned long j;
		struct rcu_node *rnp_root = rcu_get_root();
		@@ -2690,7 +2690,7 @@ static __latent_entropy void rcu_process_callbacks(struct softirq_action *unused
		local_irq_restore(flags);
		}

		rcu_check_gp_start_stall(rnp, rdp);
		rcu_check_gp_start_stall(rnp, rdp, rcu_jiffies_till_stall_check());

		/* If there are callbacks ready, invoke them. */
		if (rcu_segcblist_ready_cbs(&rdp->cblist))

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