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-rw-r--r--include/linux/hardirq.h24
-rw-r--r--include/linux/rcupdate.h6
-rw-r--r--include/linux/rcutiny.h97
3 files changed, 127 insertions, 0 deletions
diff --git a/include/linux/hardirq.h b/include/linux/hardirq.h
index 6d527ee82b2b..d5b387669dab 100644
--- a/include/linux/hardirq.h
+++ b/include/linux/hardirq.h
@@ -139,10 +139,34 @@ static inline void account_system_vtime(struct task_struct *tsk)
#endif
#if defined(CONFIG_NO_HZ)
+#if defined(CONFIG_TINY_RCU)
+extern void rcu_enter_nohz(void);
+extern void rcu_exit_nohz(void);
+
+static inline void rcu_irq_enter(void)
+{
+ rcu_exit_nohz();
+}
+
+static inline void rcu_irq_exit(void)
+{
+ rcu_enter_nohz();
+}
+
+static inline void rcu_nmi_enter(void)
+{
+}
+
+static inline void rcu_nmi_exit(void)
+{
+}
+
+#else
extern void rcu_irq_enter(void);
extern void rcu_irq_exit(void);
extern void rcu_nmi_enter(void);
extern void rcu_nmi_exit(void);
+#endif
#else
# define rcu_irq_enter() do { } while (0)
# define rcu_irq_exit() do { } while (0)
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 3ebd0b7bcb08..6dd71fa48429 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -68,11 +68,17 @@ extern int sched_expedited_torture_stats(char *page);
/* 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>
+#elif CONFIG_TINY_RCU
+#include <linux/rcutiny.h>
#else
#error "Unknown RCU implementation specified to kernel configuration"
#endif
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
new file mode 100644
index 000000000000..891073c264dc
--- /dev/null
+++ b/include/linux/rcutiny.h
@@ -0,0 +1,97 @@
+/*
+ * Read-Copy Update mechanism for mutual exclusion, the Bloatwatch edition.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ *
+ * Copyright IBM Corporation, 2008
+ *
+ * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
+ *
+ * For detailed explanation of Read-Copy Update mechanism see -
+ * Documentation/RCU
+ */
+
+#ifndef __LINUX_TINY_H
+#define __LINUX_TINY_H
+
+#include <linux/cache.h>
+
+void rcu_sched_qs(int cpu);
+void rcu_bh_qs(int cpu);
+
+#define __rcu_read_lock() preempt_disable()
+#define __rcu_read_unlock() preempt_enable()
+#define __rcu_read_lock_bh() local_bh_disable()
+#define __rcu_read_unlock_bh() local_bh_enable()
+#define call_rcu_sched call_rcu
+
+#define rcu_init_sched() do { } while (0)
+extern void rcu_check_callbacks(int cpu, int user);
+extern void __rcu_init(void);
+
+/*
+ * Return the number of grace periods.
+ */
+static inline long rcu_batches_completed(void)
+{
+ return 0;
+}
+
+/*
+ * Return the number of bottom-half grace periods.
+ */
+static inline long rcu_batches_completed_bh(void)
+{
+ return 0;
+}
+
+extern int rcu_expedited_torture_stats(char *page);
+
+static inline void synchronize_rcu_expedited(void)
+{
+ synchronize_sched();
+}
+
+static inline void synchronize_rcu_bh_expedited(void)
+{
+ synchronize_sched();
+}
+
+struct notifier_block;
+extern int rcu_cpu_notify(struct notifier_block *self,
+ unsigned long action, void *hcpu);
+
+#ifdef CONFIG_NO_HZ
+
+extern void rcu_enter_nohz(void);
+extern void rcu_exit_nohz(void);
+
+#else /* #ifdef CONFIG_NO_HZ */
+
+static inline void rcu_enter_nohz(void)
+{
+}
+
+static inline void rcu_exit_nohz(void)
+{
+}
+
+#endif /* #else #ifdef CONFIG_NO_HZ */
+
+static inline void exit_rcu(void)
+{
+}
+
+#endif /* __LINUX_RCUTINY_H */