Commit b1580501 authored by Paul E. McKenney's avatar Paul E. McKenney
Browse files

rcu: Make show_rcu_gp_kthreads() dump rcu_node structures blocking GP 



Currently, show_rcu_gp_kthreads() only dumps rcu_node structures that
have outdated ideas of the current grace-period number.  This commit
also dumps those that are in any way blocking the current grace period.
This helps diagnose RCU priority boosting failures.

Signed-off-by: default avatarPaul E. McKenney <paulmck@kernel.org>
parent 3ef5a1c3

kernel/rcu/tree_stall.h

+3 −2
Original line number Diff line number Diff line
@@ -746,8 +746,9 @@ void show_rcu_gp_kthreads(void) 
		data_race(rcu_state.gp_max),

		data_race(rcu_state.gp_flags));

	rcu_for_each_node_breadth_first(rnp) {

		if (ULONG_CMP_GE(READ_ONCE(rcu_state.gp_seq),

				 READ_ONCE(rnp->gp_seq_needed)))

		if (ULONG_CMP_GE(READ_ONCE(rcu_state.gp_seq), READ_ONCE(rnp->gp_seq_needed)) &&

		    !data_race(rnp->qsmask) && !data_race(rnp->boost_tasks) &&

		    !data_race(rnp->exp_tasks) && !data_race(rnp->gp_tasks))

			continue;

		pr_info("\trcu_node %d:%d ->gp_seq %ld ->gp_seq_needed %ld ->qsmask %#lx %c%c%c%c ->n_boosts %ld\n",

			rnp->grplo, rnp->grphi,