rcu: Add CPU-offline processing for single-node configurations

Add preemptable-RCU plugin to handle the CPU-offline
processing.

An additional plugin is forthcoming to handle multinode RCU
trees, but this current plugin works for configurations up to
32 CPUs (64 CPUs for 64-bit kernels).

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: akpm@linux-foundation.org
Cc: mathieu.desnoyers@polymtl.ca
Cc: josht@linux.vnet.ibm.com
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
LKML-Reference: <12511321213336-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 2 insertions, 0 deletions

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index cc0255714075..000b07609876 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -84,6 +84,7 @@ extern long rcu_batches_completed_sched(void);
 static void cpu_quiet_msk(unsigned long mask, struct rcu_state *rsp,
                           struct rcu_node *rnp, unsigned long flags);
 static void cpu_quiet_msk_finish(struct rcu_state *rsp, unsigned long flags);
+static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp);
 static void __rcu_process_callbacks(struct rcu_state *rsp,
                                     struct rcu_data *rdp);
 static void __call_rcu(struct rcu_head *head,
@@ -920,6 +921,7 @@ static void rcu_offline_cpu(int cpu)
 {
         __rcu_offline_cpu(cpu, &rcu_sched_state);
         __rcu_offline_cpu(cpu, &rcu_bh_state);
+        rcu_preempt_offline_cpu(cpu);
 }
 
 #else /* #ifdef CONFIG_HOTPLUG_CPU */