1 files changed, 20 insertions, 0 deletions

diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 9c71c1b18e03..f92115488187 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -1757,6 +1757,26 @@ static void rcu_prepare_for_idle(int cpu)
         if (!tne)
                 return;
 
+        /* Adaptive-tick mode, where usermode execution is idle to RCU. */
+        if (!is_idle_task(current)) {
+                rdtp->dyntick_holdoff = jiffies - 1;
+                if (rcu_cpu_has_nonlazy_callbacks(cpu)) {
+                        trace_rcu_prep_idle("User dyntick with callbacks");
+                        rdtp->idle_gp_timer_expires =
+                                round_up(jiffies + RCU_IDLE_GP_DELAY,
+                                         RCU_IDLE_GP_DELAY);
+                } else if (rcu_cpu_has_callbacks(cpu)) {
+                        rdtp->idle_gp_timer_expires =
+                                round_jiffies(jiffies + RCU_IDLE_LAZY_GP_DELAY);
+                        trace_rcu_prep_idle("User dyntick with lazy callbacks");
+                } else {
+                        return;
+                }
+                tp = &rdtp->idle_gp_timer;
+                mod_timer_pinned(tp, rdtp->idle_gp_timer_expires);
+                return;
+        }
+
         /*
          * If this is an idle re-entry, for example, due to use of
          * RCU_NONIDLE() or the new idle-loop tracing API within the idle