[PATCH 18/48] rcu: Make TINY_RCU depend on !PREEMPT_RCU rather than !PREEMPTION

From: Uladzislau Rezki (Sony)
Date: Tue May 07 2024 - 05:40:00 EST


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

Right now, TINY_RCU depends on (!PREEMPTION && !SMP), which has served the
kernel well for many years due to the fact that PREEMPT_RCU is normally
a synonym for PREEMPTION. But with the advent of lazy preemption,
it will be possible to have non-preemptible RCU in a preemptible kernel,
so that kernels could be built with PREEMPT_RCU=n and PREEMPTION=y.

This commit therefore makes TINY_RCU depend on (!PREEMPT_RCU && !SMP),
thus allowing for a non-preemptible RCU in preemptible kernels.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxx>
Cc: Ankur Arora <ankur.a.arora@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Signed-off-by: Uladzislau Rezki (Sony) <urezki@xxxxxxxxx>
---
kernel/rcu/Kconfig | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/rcu/Kconfig b/kernel/rcu/Kconfig
index e7d2dd267593..7dca0138260c 100644
--- a/kernel/rcu/Kconfig
+++ b/kernel/rcu/Kconfig
@@ -31,7 +31,7 @@ config PREEMPT_RCU

config TINY_RCU
bool
- default y if !PREEMPTION && !SMP
+ default y if !PREEMPT_RCU && !SMP
help
This option selects the RCU implementation that is
designed for UP systems from which real-time response
--
2.39.2