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PREEMPT_LAZY can be enabled stand-alone or alongside PREEMPT_DYNAMIC which allows for dynamic switching of preemption models. The choice of PREEMPT_RCU or not, however, is fixed at compile time. Given that PREEMPT_RCU makes some trade-offs to optimize for latency as opposed to throughput, configurations with limited preemption might prefer the stronger forward-progress guarantees of PREEMPT_RCU=n. Accordingly, explicitly limit PREEMPT_RCU=y to the latency oriented preemption models: PREEMPT, PREEMPT_RT, and the runtime configurable model PREEMPT_DYNAMIC. This means the throughput oriented models, PREEMPT_NONE, PREEMPT_VOLUNTARY, and PREEMPT_LAZY will run with PREEMPT_RCU=n. Cc: Paul E. McKenney <paulmck@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Reviewed-by: Frederic Weisbecker <frederic@kernel.org> Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com> Signed-off-by: Paul E. McKenney <paulmck@kernel.org> Signed-off-by: Boqun Feng <boqun.feng@gmail.com>