rcutorture: Consolidate rcu_torture_boost() timing and statistics

This commit consolidates two loops in rcu_torture_boost(), one of which
counts the number of boost-test episodes and the other of which computes
the start time of the next episode, into one loop that does both with but
a single acquisition of boost_mutex.  This means that the count of the
number of boost-test episodes is incremented after an episode completes
rather than before it starts, but it also avoids the over-counting that
was possible previously.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 3defd0febe155791ab5a5803580ec38f0464f9df..31338b2d6609e72e5801f5399b786aff12c77ad8 100644 (file)
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -956,15 +956,6 @@ static int rcu_torture_boost(void *arg)
                bool failed = false; // Test failed already in this test interval
                bool gp_initiated = false;
 
-               /* Increment n_rcu_torture_boosts once per boost-test */
-               while (!kthread_should_stop()) {
-                       if (mutex_trylock(&boost_mutex)) {
-                               n_rcu_torture_boosts++;
-                               mutex_unlock(&boost_mutex);
-                               break;
-                       }
-                       schedule_timeout_uninterruptible(1);
-               }
                if (kthread_should_stop())
                        goto checkwait;
 
@@ -1015,7 +1006,10 @@ static int rcu_torture_boost(void *arg)
                 */
                while (oldstarttime == boost_starttime && !kthread_should_stop()) {
                        if (mutex_trylock(&boost_mutex)) {
-                               boost_starttime = jiffies + test_boost_interval * HZ;
+                               if (oldstarttime == boost_starttime) {
+                                       boost_starttime = jiffies + test_boost_interval * HZ;
+                                       n_rcu_torture_boosts++;
+                               }
                                mutex_unlock(&boost_mutex);
                                break;
                        }