Merge branch 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull RCU updates from Ingo Molnar:
 "The major changes:

  - Simplify RCU's grace-period and callback processing based on the new
    numbering for callbacks.

  - Removal of TINY_PREEMPT_RCU in favor of TREE_PREEMPT_RCU for
    single-CPU low-latency systems.

  - SRCU-related changes and fixes.

  - Miscellaneous fixes, including converting a few remaining printk()
    calls to pr_*().

  - Documentation updates"

* 'core-rcu-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (32 commits)
  rcu: Shrink TINY_RCU by reworking CPU-stall ifdefs
  rcu: Shrink TINY_RCU by moving exit_rcu()
  rcu: Remove TINY_PREEMPT_RCU tracing documentation
  rcu: Consolidate rcutiny_plugin.h ifdefs
  rcu: Remove rcu_preempt_note_context_switch()
  rcu: Remove the CONFIG_TINY_RCU ifdefs in rcutiny.h
  rcu: Remove check_cpu_stall_preempt()
  rcu: Simplify RCU_TINY RCU callback invocation
  rcu: Remove rcu_preempt_process_callbacks()
  rcu: Remove rcu_preempt_remove_callbacks()
  rcu: Remove rcu_preempt_check_callbacks()
  rcu: Remove show_tiny_preempt_stats()
  rcu: Remove TINY_PREEMPT_RCU
  powerpc,kvm: fix imbalance srcu_read_[un]lock()
  rcu: Remove srcu_read_lock_raw() and srcu_read_unlock_raw().
  rcu: Apply Dave Jones's NOCB Kconfig help feedback
  rcu: Merge adjacent identical ifdefs
  rcu: Drive quiescent-state-forcing delay from HZ
  rcu: Remove "Experimental" flags
  kthread: Add kworker kthreads to OS-jitter documentation
  ...

1 files changed, 11 insertions, 10 deletions

diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
index a0714a51b6d7..aa344111de3e 100644
--- a/kernel/rcutiny.c
+++ b/kernel/rcutiny.c
@@ -44,7 +44,6 @@
 
 /* Forward declarations for rcutiny_plugin.h. */
 struct rcu_ctrlblk;
-static void invoke_rcu_callbacks(void);
 static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp);
 static void rcu_process_callbacks(struct softirq_action *unused);
 static void __call_rcu(struct rcu_head *head,
@@ -205,7 +204,7 @@ static int rcu_is_cpu_rrupt_from_idle(void)
  */
 static int rcu_qsctr_help(struct rcu_ctrlblk *rcp)
 {
-	reset_cpu_stall_ticks(rcp);
+	RCU_TRACE(reset_cpu_stall_ticks(rcp));
 	if (rcp->rcucblist != NULL &&
 	    rcp->donetail != rcp->curtail) {
 		rcp->donetail = rcp->curtail;
@@ -227,7 +226,7 @@ void rcu_sched_qs(int cpu)
 	local_irq_save(flags);
 	if (rcu_qsctr_help(&rcu_sched_ctrlblk) +
 	    rcu_qsctr_help(&rcu_bh_ctrlblk))
-		invoke_rcu_callbacks();
+		raise_softirq(RCU_SOFTIRQ);
 	local_irq_restore(flags);
 }
 
@@ -240,7 +239,7 @@ void rcu_bh_qs(int cpu)
 
 	local_irq_save(flags);
 	if (rcu_qsctr_help(&rcu_bh_ctrlblk))
-		invoke_rcu_callbacks();
+		raise_softirq(RCU_SOFTIRQ);
 	local_irq_restore(flags);
 }
 
@@ -252,12 +251,11 @@ void rcu_bh_qs(int cpu)
  */
 void rcu_check_callbacks(int cpu, int user)
 {
-	check_cpu_stalls();
+	RCU_TRACE(check_cpu_stalls());
 	if (user || rcu_is_cpu_rrupt_from_idle())
 		rcu_sched_qs(cpu);
 	else if (!in_softirq())
 		rcu_bh_qs(cpu);
-	rcu_preempt_check_callbacks();
 }
 
 /*
@@ -278,7 +276,7 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp)
 					      ACCESS_ONCE(rcp->rcucblist),
 					      need_resched(),
 					      is_idle_task(current),
-					      rcu_is_callbacks_kthread()));
+					      false));
 		return;
 	}
 
@@ -290,7 +288,6 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp)
 	*rcp->donetail = NULL;
 	if (rcp->curtail == rcp->donetail)
 		rcp->curtail = &rcp->rcucblist;
-	rcu_preempt_remove_callbacks(rcp);
 	rcp->donetail = &rcp->rcucblist;
 	local_irq_restore(flags);
 
@@ -309,14 +306,13 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp)
 	RCU_TRACE(rcu_trace_sub_qlen(rcp, cb_count));
 	RCU_TRACE(trace_rcu_batch_end(rcp->name, cb_count, 0, need_resched(),
 				      is_idle_task(current),
-				      rcu_is_callbacks_kthread()));
+				      false));
 }
 
 static void rcu_process_callbacks(struct softirq_action *unused)
 {
 	__rcu_process_callbacks(&rcu_sched_ctrlblk);
 	__rcu_process_callbacks(&rcu_bh_ctrlblk);
-	rcu_preempt_process_callbacks();
 }
 
 /*
@@ -382,3 +378,8 @@ void call_rcu_bh(struct rcu_head *head, void (*func)(struct rcu_head *rcu))
 	__call_rcu(head, func, &rcu_bh_ctrlblk);
 }
 EXPORT_SYMBOL_GPL(call_rcu_bh);
+
+void rcu_init(void)
+{
+	open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
+}