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>
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 433f426..074cb2d 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 @@
.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;
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index e51373c..b6c2335 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -443,6 +443,7 @@
unsigned long gp_max; /* Maximum GP duration in */
/* jiffies. */
char *name; /* Name of structure. */
+ char abbr; /* Abbreviated name. */
struct list_head flavors; /* List of RCU flavors. */
};
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index e32236e..c016444 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -111,7 +111,7 @@
#ifdef CONFIG_TREE_PREEMPT_RCU
struct rcu_state rcu_preempt_state =
- RCU_STATE_INITIALIZER(rcu_preempt, call_rcu);
+ RCU_STATE_INITIALIZER(rcu_preempt, 'p', call_rcu);
DEFINE_PER_CPU(struct rcu_data, rcu_preempt_data);
static struct rcu_state *rcu_state = &rcu_preempt_state;
@@ -2517,7 +2517,8 @@
return;
for_each_cpu(cpu, rcu_nocb_mask) {
rdp = per_cpu_ptr(rsp->rda, cpu);
- t = kthread_run(rcu_nocb_kthread, rdp, "rcuo%d", cpu);
+ t = kthread_run(rcu_nocb_kthread, rdp,
+ "rcuo%c/%d", rsp->abbr, cpu);
BUG_ON(IS_ERR(t));
ACCESS_ONCE(rdp->nocb_kthread) = t;
}