diff mbox series

[12/30] rcu: limit PREEMPT_RCU to full preemption under PREEMPT_AUTO

Message ID 20240213055554.1802415-13-ankur.a.arora@oracle.com
State New
Headers
Series PREEMPT_AUTO: support lazy rescheduling |

Commit Message

Ankur Arora Feb. 13, 2024, 5:55 a.m. UTC 
  Under PREEMPT_AUTO, CONFIG_PREEMPTION is enabled, and much like
PREEMPT_DYNAMIC, PREEMPT_AUTO also allows for dynamic switching
of preemption models.

The RCU model, however, is fixed at compile time.

Now, RCU typically selects PREEMPT_RCU if CONFIG_PREEMPTION is enabled.
Given the trade-offs between PREEMPT_RCU=y and PREEMPT_RCU=n, some
configurations might prefer the stronger forward-progress guarantees
of PREEMPT_RCU=n.

Accordingly, select PREEMPT_RCU=y only if the user selects
CONFIG_PREEMPT at compile time.

Suggested-by: Paul E. McKenney <paulmck@kernel.org>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
---
 kernel/rcu/Kconfig | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
diff mbox series

Patch

diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
index bdd7eadb33d8..d0ecc8ef17a7 100644
--- a/kernel/rcu/Kconfig
+++ b/kernel/rcu/Kconfig
@@ -18,7 +18,7 @@  config TREE_RCU
 
 config PREEMPT_RCU
 	bool
-	default y if PREEMPTION
+	default y if (PREEMPT || PREEMPT_DYNAMIC || PREEMPT_RT)
 	select TREE_RCU
 	help
 	  This option selects the RCU implementation that is