rcu: Add rcu_expedite_gp() and rcu_unexpedite_gp() to rcutorture

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

1 files changed, 25 insertions, 0 deletions

diff --git a/kernel/rcu/rcutorture.c b/kernel/rcu/rcutorture.c
index 30d42aa55d83..3833aa611ae7 100644
--- a/kernel/rcu/rcutorture.c
+++ b/kernel/rcu/rcutorture.c
@@ -853,6 +853,8 @@ rcu_torture_fqs(void *arg)
 static int
 rcu_torture_writer(void *arg)
 {
+        bool can_expedite = !rcu_gp_is_expedited();
+        int expediting = 0;
         unsigned long gp_snap;
         bool gp_cond1 = gp_cond, gp_exp1 = gp_exp, gp_normal1 = gp_normal;
         bool gp_sync1 = gp_sync;
@@ -865,6 +867,12 @@ rcu_torture_writer(void *arg)
         int nsynctypes = 0;
 
         VERBOSE_TOROUT_STRING("rcu_torture_writer task started");
+        pr_alert("%s" TORTURE_FLAG
+                 " Grace periods expedited from boot/sysfs for %s,\n",
+                 torture_type, cur_ops->name);
+        pr_alert("%s" TORTURE_FLAG
+                 " Testing of dynamic grace-period expediting diabled.\n",
+                 torture_type);
 
         /* Initialize synctype[] array.  If none set, take default. */
         if (!gp_cond1 && !gp_exp1 && !gp_normal1 && !gp_sync)
@@ -949,9 +957,26 @@ rcu_torture_writer(void *arg)
                         }
                 }
                 rcutorture_record_progress(++rcu_torture_current_version);
+                /* Cycle through nesting levels of rcu_expedite_gp() calls. */
+                if (can_expedite &&
+                    !(torture_random(&rand) & 0xff & (!!expediting - 1))) {
+                        WARN_ON_ONCE(expediting == 0 && rcu_gp_is_expedited());
+                        if (expediting >= 0)
+                                rcu_expedite_gp();
+                        else
+                                rcu_unexpedite_gp();
+                        if (++expediting > 3)
+                                expediting = -expediting;
+                }
                 rcu_torture_writer_state = RTWS_STUTTER;
                 stutter_wait("rcu_torture_writer");
         } while (!torture_must_stop());
+        /* Reset expediting back to unexpedited. */
+        if (expediting > 0)
+                expediting = -expediting;
+        while (can_expedite && expediting++ < 0)
+                rcu_unexpedite_gp();
+        WARN_ON_ONCE(can_expedite && rcu_gp_is_expedited());
         rcu_torture_writer_state = RTWS_STOPPING;
         torture_kthread_stopping("rcu_torture_writer");
         return 0;