[PATCH rcu 0/4] Refactor TASKS_RCU for lazy preemption

From: Paul E. McKenney
Date: Thu Feb 22 2024 - 19:26:28 EST


Hello!

This series refactors the NEED_TASKS_RCU option so that the conditional
processing is in one place in kernel/rcu/Kconfig. This makes it easier
to make sure that Tasks RCU is enabled in PREEMPT_AUTO kernels, given
that such kernels are preemptible, even if only lazily so. After all,
it takes only one lazy preemption from a trampoline to significantly
degrade your kernel's actuarial statistics.

1. Create NEED_TASKS_RCU to factor out enablement logic.

2. Select new NEED_TASKS_RCU Kconfig option.

3. Select new NEED_TASKS_RCU Kconfig option.

4. Select new NEED_TASKS_RCU Kconfig option.

Thanx, Paul

------------------------------------------------------------------------

arch/Kconfig | 4 ++--
kernel/bpf/Kconfig | 2 +-
kernel/rcu/Kconfig | 6 +++++-
kernel/trace/Kconfig | 4 ++--
4 files changed, 10 insertions(+), 6 deletions(-)