rcu: Remove obsolete force-quiescent-state statistics for debugfs

The debugfs interface displayed statistics on RCU-pending checks but
this interface has since been removed.  This commit therefore removes the
no-longer-used rcu_state structure's ->n_force_qs_lh and ->n_force_qs_ngp
fields along with their updates.  (Though the ->n_force_qs_ngp field
was actually not used at all, embarrassingly enough.)

If this information proves necessary in the future, the corresponding
event traces will be added.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 99d59be..86fc087 100644 (file)
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2844,10 +2844,8 @@ static void force_quiescent_state(struct rcu_state *rsp)
                      !raw_spin_trylock(&rnp->fqslock);
                if (rnp_old != NULL)
                        raw_spin_unlock(&rnp_old->fqslock);
-               if (ret) {
-                       rsp->n_force_qs_lh++;
+               if (ret)
                        return;
-               }
                rnp_old = rnp;
        }
        /* rnp_old == rcu_get_root(rsp), rnp == NULL. */
@@ -2856,7 +2854,6 @@ static void force_quiescent_state(struct rcu_state *rsp)
        raw_spin_lock_irqsave_rcu_node(rnp_old, flags);
        raw_spin_unlock(&rnp_old->fqslock);
        if (READ_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) {
-               rsp->n_force_qs_lh++;
                raw_spin_unlock_irqrestore_rcu_node(rnp_old, flags);
                return;  /* Someone beat us to it. */
        }

diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index d29bab8..2edd563 100644 (file)
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -355,10 +355,6 @@ struct rcu_state {
                                                /*  kthreads, if configured. */
        unsigned long n_force_qs;               /* Number of calls to */
                                                /*  force_quiescent_state(). */
-       unsigned long n_force_qs_lh;            /* ~Number of calls leaving */
-                                               /*  due to lock unavailable. */
-       unsigned long n_force_qs_ngp;           /* Number of calls leaving */
-                                               /*  due to no GP active. */
        unsigned long gp_start;                 /* Time at which GP started, */
                                                /*  but in jiffies. */
        unsigned long gp_activity;              /* Time of last GP kthread */