rcu: Re-arrange code to reduce #ifdef pain
Remove #ifdefs from kernel/rcupdate.c and
include/linux/rcupdate.h by moving code to
include/linux/rcutiny.h, include/linux/rcutree.h, and
kernel/rcutree.c.
Also remove some definitions that are no longer used.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: laijs@cn.fujitsu.com
Cc: dipankar@in.ibm.com
Cc: mathieu.desnoyers@polymtl.ca
Cc: josh@joshtriplett.org
Cc: dvhltc@us.ibm.com
Cc: niv@us.ibm.com
Cc: peterz@infradead.org
Cc: rostedt@goodmis.org
Cc: Valdis.Kletnieks@vt.edu
Cc: dhowells@redhat.com
LKML-Reference: <1258908830885-git-send-email->
Signed-off-by: Ingo Molnar <mingo@elte.hu>
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 2f1bc42..24440f4 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -52,11 +52,6 @@
};
/* Exported common interfaces */
-#ifdef CONFIG_TREE_PREEMPT_RCU
-extern void synchronize_rcu(void);
-#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
-#define synchronize_rcu synchronize_sched
-#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
extern void synchronize_rcu_bh(void);
extern void synchronize_sched(void);
extern void rcu_barrier(void);
@@ -67,13 +62,6 @@
/* Internal to kernel */
extern void rcu_init(void);
-extern void rcu_scheduler_starting(void);
-#ifndef CONFIG_TINY_RCU
-extern int rcu_needs_cpu(int cpu);
-#else
-static inline int rcu_needs_cpu(int cpu) { return 0; }
-#endif
-extern int rcu_scheduler_active;
#if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU)
#include <linux/rcutree.h>
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index a3b6272..c4ba9a7 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -39,6 +39,11 @@
#define rcu_init_sched() do { } while (0)
extern void rcu_check_callbacks(int cpu, int user);
+static inline int rcu_needs_cpu(int cpu)
+{
+ return 0;
+}
+
/*
* Return the number of grace periods.
*/
@@ -57,6 +62,8 @@
extern int rcu_expedited_torture_stats(char *page);
+#define synchronize_rcu synchronize_sched
+
static inline void synchronize_rcu_expedited(void)
{
synchronize_sched();
@@ -86,6 +93,10 @@
#endif /* #else #ifdef CONFIG_NO_HZ */
+static inline void rcu_scheduler_starting(void)
+{
+}
+
static inline void exit_rcu(void)
{
}
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index 111a652..c93eee5 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -35,12 +35,14 @@
extern void rcu_sched_qs(int cpu);
extern void rcu_bh_qs(int cpu);
extern int rcu_needs_cpu(int cpu);
+extern void rcu_scheduler_starting(void);
extern int rcu_expedited_torture_stats(char *page);
#ifdef CONFIG_TREE_PREEMPT_RCU
extern void __rcu_read_lock(void);
extern void __rcu_read_unlock(void);
+extern void synchronize_rcu(void);
extern void exit_rcu(void);
#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
@@ -55,7 +57,7 @@
preempt_enable();
}
-#define __synchronize_sched() synchronize_rcu()
+#define synchronize_rcu synchronize_sched
static inline void exit_rcu(void)
{
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index eb6b534..9b7fd47 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -44,7 +44,6 @@
#include <linux/cpu.h>
#include <linux/mutex.h>
#include <linux/module.h>
-#include <linux/kernel_stat.h>
#ifdef CONFIG_DEBUG_LOCK_ALLOC
static struct lock_class_key rcu_lock_key;
@@ -53,8 +52,6 @@
EXPORT_SYMBOL_GPL(rcu_lock_map);
#endif
-int rcu_scheduler_active __read_mostly;
-
/*
* Awaken the corresponding synchronize_rcu() instance now that a
* grace period has elapsed.
@@ -66,104 +63,3 @@
rcu = container_of(head, struct rcu_synchronize, head);
complete(&rcu->completion);
}
-
-#ifndef CONFIG_TINY_RCU
-
-#ifdef CONFIG_TREE_PREEMPT_RCU
-
-/**
- * synchronize_rcu - wait until a grace period has elapsed.
- *
- * Control will return to the caller some time after a full grace
- * period has elapsed, in other words after all currently executing RCU
- * read-side critical sections have completed. RCU read-side critical
- * sections are delimited by rcu_read_lock() and rcu_read_unlock(),
- * and may be nested.
- */
-void synchronize_rcu(void)
-{
- struct rcu_synchronize rcu;
-
- if (!rcu_scheduler_active)
- return;
-
- init_completion(&rcu.completion);
- /* Will wake me after RCU finished. */
- call_rcu(&rcu.head, wakeme_after_rcu);
- /* Wait for it. */
- wait_for_completion(&rcu.completion);
-}
-EXPORT_SYMBOL_GPL(synchronize_rcu);
-
-#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
-
-/**
- * synchronize_sched - wait until an rcu-sched grace period has elapsed.
- *
- * Control will return to the caller some time after a full rcu-sched
- * grace period has elapsed, in other words after all currently executing
- * rcu-sched read-side critical sections have completed. These read-side
- * critical sections are delimited by rcu_read_lock_sched() and
- * rcu_read_unlock_sched(), and may be nested. Note that preempt_disable(),
- * local_irq_disable(), and so on may be used in place of
- * rcu_read_lock_sched().
- *
- * This means that all preempt_disable code sequences, including NMI and
- * hardware-interrupt handlers, in progress on entry will have completed
- * before this primitive returns. However, this does not guarantee that
- * softirq handlers will have completed, since in some kernels, these
- * handlers can run in process context, and can block.
- *
- * This primitive provides the guarantees made by the (now removed)
- * synchronize_kernel() API. In contrast, synchronize_rcu() only
- * guarantees that rcu_read_lock() sections will have completed.
- * In "classic RCU", these two guarantees happen to be one and
- * the same, but can differ in realtime RCU implementations.
- */
-void synchronize_sched(void)
-{
- struct rcu_synchronize rcu;
-
- if (rcu_blocking_is_gp())
- return;
-
- init_completion(&rcu.completion);
- /* Will wake me after RCU finished. */
- call_rcu_sched(&rcu.head, wakeme_after_rcu);
- /* Wait for it. */
- wait_for_completion(&rcu.completion);
-}
-EXPORT_SYMBOL_GPL(synchronize_sched);
-
-/**
- * synchronize_rcu_bh - wait until an rcu_bh grace period has elapsed.
- *
- * Control will return to the caller some time after a full rcu_bh grace
- * period has elapsed, in other words after all currently executing rcu_bh
- * read-side critical sections have completed. RCU read-side critical
- * sections are delimited by rcu_read_lock_bh() and rcu_read_unlock_bh(),
- * and may be nested.
- */
-void synchronize_rcu_bh(void)
-{
- struct rcu_synchronize rcu;
-
- if (rcu_blocking_is_gp())
- return;
-
- init_completion(&rcu.completion);
- /* Will wake me after RCU finished. */
- call_rcu_bh(&rcu.head, wakeme_after_rcu);
- /* Wait for it. */
- wait_for_completion(&rcu.completion);
-}
-EXPORT_SYMBOL_GPL(synchronize_rcu_bh);
-
-#endif /* #ifndef CONFIG_TINY_RCU */
-
-void rcu_scheduler_starting(void)
-{
- WARN_ON(num_online_cpus() != 1);
- WARN_ON(nr_context_switches() > 0);
- rcu_scheduler_active = 1;
-}
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index e3d3bbd..4ca7e02 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -46,6 +46,7 @@
#include <linux/cpu.h>
#include <linux/mutex.h>
#include <linux/time.h>
+#include <linux/kernel_stat.h>
#include "rcutree.h"
@@ -79,6 +80,8 @@
struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state);
DEFINE_PER_CPU(struct rcu_data, rcu_bh_data);
+static int rcu_scheduler_active __read_mostly;
+
/*
* Return true if an RCU grace period is in progress. The ACCESS_ONCE()s
@@ -1396,6 +1399,68 @@
}
EXPORT_SYMBOL_GPL(call_rcu_bh);
+/**
+ * synchronize_sched - wait until an rcu-sched grace period has elapsed.
+ *
+ * Control will return to the caller some time after a full rcu-sched
+ * grace period has elapsed, in other words after all currently executing
+ * rcu-sched read-side critical sections have completed. These read-side
+ * critical sections are delimited by rcu_read_lock_sched() and
+ * rcu_read_unlock_sched(), and may be nested. Note that preempt_disable(),
+ * local_irq_disable(), and so on may be used in place of
+ * rcu_read_lock_sched().
+ *
+ * This means that all preempt_disable code sequences, including NMI and
+ * hardware-interrupt handlers, in progress on entry will have completed
+ * before this primitive returns. However, this does not guarantee that
+ * softirq handlers will have completed, since in some kernels, these
+ * handlers can run in process context, and can block.
+ *
+ * This primitive provides the guarantees made by the (now removed)
+ * synchronize_kernel() API. In contrast, synchronize_rcu() only
+ * guarantees that rcu_read_lock() sections will have completed.
+ * In "classic RCU", these two guarantees happen to be one and
+ * the same, but can differ in realtime RCU implementations.
+ */
+void synchronize_sched(void)
+{
+ struct rcu_synchronize rcu;
+
+ if (rcu_blocking_is_gp())
+ return;
+
+ init_completion(&rcu.completion);
+ /* Will wake me after RCU finished. */
+ call_rcu_sched(&rcu.head, wakeme_after_rcu);
+ /* Wait for it. */
+ wait_for_completion(&rcu.completion);
+}
+EXPORT_SYMBOL_GPL(synchronize_sched);
+
+/**
+ * synchronize_rcu_bh - wait until an rcu_bh grace period has elapsed.
+ *
+ * Control will return to the caller some time after a full rcu_bh grace
+ * period has elapsed, in other words after all currently executing rcu_bh
+ * read-side critical sections have completed. RCU read-side critical
+ * sections are delimited by rcu_read_lock_bh() and rcu_read_unlock_bh(),
+ * and may be nested.
+ */
+void synchronize_rcu_bh(void)
+{
+ struct rcu_synchronize rcu;
+
+ if (rcu_blocking_is_gp())
+ return;
+
+ init_completion(&rcu.completion);
+ /* Will wake me after RCU finished. */
+ call_rcu_bh(&rcu.head, wakeme_after_rcu);
+ /* Wait for it. */
+ wait_for_completion(&rcu.completion);
+}
+EXPORT_SYMBOL_GPL(synchronize_rcu_bh);
+
/*
* Check to see if there is any immediate RCU-related work to be done
* by the current CPU, for the specified type of RCU, returning 1 if so.
@@ -1480,6 +1545,21 @@
rcu_preempt_needs_cpu(cpu);
}
+/*
+ * This function is invoked towards the end of the scheduler's initialization
+ * process. Before this is called, the idle task might contain
+ * RCU read-side critical sections (during which time, this idle
+ * task is booting the system). After this function is called, the
+ * idle tasks are prohibited from containing RCU read-side critical
+ * sections.
+ */
+void rcu_scheduler_starting(void)
+{
+ WARN_ON(num_online_cpus() != 1);
+ WARN_ON(nr_context_switches() > 0);
+ rcu_scheduler_active = 1;
+}
+
static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL};
static atomic_t rcu_barrier_cpu_count;
static DEFINE_MUTEX(rcu_barrier_mutex);
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 0bdb592..1d295c7 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -425,6 +425,30 @@
}
EXPORT_SYMBOL_GPL(call_rcu);
+/**
+ * synchronize_rcu - wait until a grace period has elapsed.
+ *
+ * Control will return to the caller some time after a full grace
+ * period has elapsed, in other words after all currently executing RCU
+ * read-side critical sections have completed. RCU read-side critical
+ * sections are delimited by rcu_read_lock() and rcu_read_unlock(),
+ * and may be nested.
+ */
+void synchronize_rcu(void)
+{
+ struct rcu_synchronize rcu;
+
+ if (!rcu_scheduler_active)
+ return;
+
+ init_completion(&rcu.completion);
+ /* Will wake me after RCU finished. */
+ call_rcu(&rcu.head, wakeme_after_rcu);
+ /* Wait for it. */
+ wait_for_completion(&rcu.completion);
+}
+EXPORT_SYMBOL_GPL(synchronize_rcu);
+
/*
* Wait for an rcu-preempt grace period. We are supposed to expedite the
* grace period, but this is the crude slow compatability hack, so just
