rcu: Allow task-level idle entry/exit nesting

The current task-level idle entry/exit code forces an entry/exit on
each call, regardless of the nesting level.  This commit therefore
properly accounts for nesting.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Frederic Weisbecker <fweisbec@gmail.com>

1 files changed, 8 insertions, 6 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 264f0284c0bd..518e08428b2e 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -418,11 +418,12 @@ static void rcu_eqs_enter(bool user)
         rdtp = this_cpu_ptr(&rcu_dynticks);
         oldval = rdtp->dynticks_nesting;
         WARN_ON_ONCE((oldval & DYNTICK_TASK_NEST_MASK) == 0);
-        if ((oldval & DYNTICK_TASK_NEST_MASK) == DYNTICK_TASK_NEST_VALUE)
+        if ((oldval & DYNTICK_TASK_NEST_MASK) == DYNTICK_TASK_NEST_VALUE) {
                 rdtp->dynticks_nesting = 0;
-        else
+                rcu_eqs_enter_common(rdtp, oldval, user);
+        } else {
                 rdtp->dynticks_nesting -= DYNTICK_TASK_NEST_VALUE;
-        rcu_eqs_enter_common(rdtp, oldval, user);
+        }
 }
 
 /**
@@ -540,11 +541,12 @@ static void rcu_eqs_exit(bool user)
         rdtp = this_cpu_ptr(&rcu_dynticks);
         oldval = rdtp->dynticks_nesting;
         WARN_ON_ONCE(oldval < 0);
-        if (oldval & DYNTICK_TASK_NEST_MASK)
+        if (oldval & DYNTICK_TASK_NEST_MASK) {
                 rdtp->dynticks_nesting += DYNTICK_TASK_NEST_VALUE;
-        else
+        } else {
                 rdtp->dynticks_nesting = DYNTICK_TASK_EXIT_IDLE;
-        rcu_eqs_exit_common(rdtp, oldval, user);
+                rcu_eqs_exit_common(rdtp, oldval, user);
+        }
 }
 
 /**