rcu: Distinguish "rcuo" kthreads by RCU flavor

Currently, the per-no-CBs-CPU kthreads are named "rcuo" followed by
the CPU number, for example, "rcuo".  This is problematic given that
there are either two or three RCU flavors, each of which gets a per-CPU
kthread with exactly the same name.  This commit therefore introduces
a one-letter abbreviation for each RCU flavor, namely 'b' for RCU-bh,
'p' for RCU-preempt, and 's' for RCU-sched.  This abbreviation is used
to distinguish the "rcuo" kthreads, for example, for CPU 0 we would have
"rcuob/0", "rcuop/0", and "rcuos/0".

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Tested-by: Dietmar Eggemann <dietmar.eggemann@arm.com>

1 files changed, 4 insertions, 3 deletions

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 433f426c848f..074cb2d974bf 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -64,7 +64,7 @@
 static struct lock_class_key rcu_node_class[RCU_NUM_LVLS];
 static struct lock_class_key rcu_fqs_class[RCU_NUM_LVLS];
 
-#define RCU_STATE_INITIALIZER(sname, cr) { \
+#define RCU_STATE_INITIALIZER(sname, sabbr, cr) { \
         .level = { &sname##_state.node[0] }, \
         .call = cr, \
         .fqs_state = RCU_GP_IDLE, \
@@ -76,13 +76,14 @@ static struct lock_class_key rcu_fqs_class[RCU_NUM_LVLS];
         .barrier_mutex = __MUTEX_INITIALIZER(sname##_state.barrier_mutex), \
         .onoff_mutex = __MUTEX_INITIALIZER(sname##_state.onoff_mutex), \
         .name = #sname, \
+        .abbr = sabbr, \
 }
 
 struct rcu_state rcu_sched_state =
-        RCU_STATE_INITIALIZER(rcu_sched, call_rcu_sched);
+        RCU_STATE_INITIALIZER(rcu_sched, 's', call_rcu_sched);
 DEFINE_PER_CPU(struct rcu_data, rcu_sched_data);
 
-struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh, call_rcu_bh);
+struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh, 'b', call_rcu_bh);
 DEFINE_PER_CPU(struct rcu_data, rcu_bh_data);
 
 static struct rcu_state *rcu_state;