Commit 5d8a752e authored Mar 20, 2019 by Zhouyi Zhou Committed by Paul E. McKenney Mar 26, 2019

rcu: Fix force_qs_rnp() header comment



Previously, threads blocked on offlining CPUS were migrated to the
root rcu_node structure, thus requiring RCU priority boosting on this
structure.  However, since commit d19fb8d1 ("rcu: Don't migrate
blocked tasks even if all corresponding CPUs offline"), RCU does not
migrate blocked tasks.  Consequently, RCU no longer does RCU priority
boosting on the root rcu_node structure as of commit 1be0085b ("rcu:
Don't initiate RCU priority boosting on root rcu_node").

This commit therefore brings comments for the force_qs_rnp() function's
header comment in line with this new no-root-boosting reality.

Signed-off-by: Zhouyi Zhou <zhouzhouyi@gmail.com>
[ paulmck: Also remove obsolete comment on suppressing new grace periods. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>

parent 85f2b60c

kernel/rcu/tree.c

+5 −5

Original line number	Diff line number	Diff line
		@@ -2548,11 +2548,11 @@ void rcu_sched_clock_irq(int user)
		}

		/*
		* Scan the leaf rcu_node structures, processing dyntick state for any that
		* have not yet encountered a quiescent state, using the function specified.
		* Also initiate boosting for any threads blocked on the root rcu_node.
		*
		* The caller must have suppressed start of new grace periods.
		* Scan the leaf rcu_node structures. For each structure on which all
		* CPUs have reported a quiescent state and on which there are tasks
		* blocking the current grace period, initiate RCU priority boosting.
		* Otherwise, invoke the specified function to check dyntick state for
		* each CPU that has not yet reported a quiescent state.
		*/
		static void force_qs_rnp(int (f)(struct rcu_data rdp))
		{