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>

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 264f028..518e084 100644 (file)
--- 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);
+       }
 }
 
 /**