rcu: Use smp_hotplug_thread facility for RCUs per-CPU kthread

Bring RCU into the new-age CPU-hotplug fold by modifying RCU's per-CPU
kthread code to use the new smp_hotplug_thread facility.

[ tglx: Adapted it to use callbacks and to the simplified rcu yield ]
    
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Namhyung Kim <namhyung@kernel.org>
Link: http://lkml.kernel.org/r/20120716103948.673354828@linutronix.de
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

1 files changed, 0 insertions, 8 deletions

diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index f08176172546..1224d4c05382 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -196,12 +196,6 @@ struct rcu_node {
                                 /* Refused to boost: not sure why, though. */
                                 /*  This can happen due to race conditions. */
 #endif /* #ifdef CONFIG_RCU_BOOST */
-        struct task_struct *node_kthread_task;
-                                /* kthread that takes care of this rcu_node */
-                                /*  structure, for example, awakening the */
-                                /*  per-CPU kthreads as needed. */
-        unsigned int node_kthread_status;
-                                /* State of node_kthread_task for tracing. */
 } ____cacheline_internodealigned_in_smp;
 
 /*
@@ -468,7 +462,6 @@ static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp);
 #ifdef CONFIG_HOTPLUG_CPU
 static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp,
                                       unsigned long flags);
-static void rcu_stop_cpu_kthread(int cpu);
 #endif /* #ifdef CONFIG_HOTPLUG_CPU */
 static void rcu_print_detail_task_stall(struct rcu_state *rsp);
 static int rcu_print_task_stall(struct rcu_node *rnp);
@@ -494,7 +487,6 @@ static void rcu_preempt_do_callbacks(void);
 static int __cpuinit rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
                                                  struct rcu_node *rnp);
 #endif /* #ifdef CONFIG_RCU_BOOST */
-static void rcu_cpu_kthread_setrt(int cpu, int to_rt);
 static void __cpuinit rcu_prepare_kthreads(int cpu);
 static void rcu_prepare_for_idle_init(int cpu);
 static void rcu_cleanup_after_idle(int cpu);