[PATCH tip/core/rcu 04/16] rcu: Allow task-level idle entry/exit nesting

[Paul E. McKenney]

From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>

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@xxxxxxxxxxxxxxxxxx>
Reviewed-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
---
 kernel/rcu/tree.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index c01213b19dee..acbfead2eb82 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);
+	}
 }
 
 /**
-- 
1.8.1.5

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