rcu: Remove CONFIG_PROVE_RCU_DELAY

The CONFIG_PROVE_RCU_DELAY Kconfig parameter doesn't appear to be very
effective at finding race conditions, so this commit removes it.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Andi Kleen <ak@linux.intel.com>
[ paulmck: Remove definition and uses as noted by Paul Bolle. ]

2 files changed, 0 insertions, 8 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index a6c5424ffa38..1b70cb6fbe3c 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -1647,11 +1647,6 @@ static int rcu_gp_init(struct rcu_state *rsp)
                                             rnp->level, rnp->grplo,
                                             rnp->grphi, rnp->qsmask);
                 raw_spin_unlock_irq(&rnp->lock);
-#ifdef CONFIG_PROVE_RCU_DELAY
-                if ((prandom_u32() % (rcu_num_nodes + 1)) == 0 &&
-                    system_state == SYSTEM_RUNNING)
-                        udelay(200);
-#endif /* #ifdef CONFIG_PROVE_RCU_DELAY */
                 cond_resched();
         }
 
diff --git a/kernel/rcu/update.c b/kernel/rcu/update.c
index bc7883570530..4056d7992a6c 100644
--- a/kernel/rcu/update.c
+++ b/kernel/rcu/update.c
@@ -90,9 +90,6 @@ void __rcu_read_unlock(void)
         } else {
                 barrier();  /* critical section before exit code. */
                 t->rcu_read_lock_nesting = INT_MIN;
-#ifdef CONFIG_PROVE_RCU_DELAY
-                udelay(10); /* Make preemption more probable. */
-#endif /* #ifdef CONFIG_PROVE_RCU_DELAY */
                 barrier();  /* assign before ->rcu_read_unlock_special load */
                 if (unlikely(ACCESS_ONCE(t->rcu_read_unlock_special)))
                         rcu_read_unlock_special(t);