Commit-ID: 29ce831000081dd757d3116bf774aafffc4b6b20
Gitweb: http://git.kernel.org/tip/29ce831000081dd757d3116bf774aafffc4b6b20
Author: Gleb Natapov <gleb@xxxxxxxxxx>
AuthorDate: Wed, 4 May 2011 16:31:03 +0300
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Thu, 5 May 2011 23:16:59 -0700
rcu: provide rcu_virt_note_context_switch() function.
Provide rcu_virt_note_context_switch() for vitalization use to note
quiescent state during guest entry.
Signed-off-by: Gleb Natapov <gleb@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
include/linux/rcutiny.h | 8 ++++++++
include/linux/rcutree.h | 10 ++++++++++
kernel/rcutree.c | 1 +
3 files changed, 19 insertions(+), 0 deletions(-)
diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h
index 30ebd7c..52b3e02 100644
--- a/include/linux/rcutiny.h
+++ b/include/linux/rcutiny.h
@@ -100,6 +100,14 @@ static inline void rcu_note_context_switch(int cpu)
}
/*
+ * Take advantage of the fact that there is only one CPU, which
+ * allows us to ignore virtualization-based context switches.
+ */
+static inline void rcu_virt_note_context_switch(int cpu)
+{
+}
+
+/*
* Return the number of grace periods.
*/
static inline long rcu_batches_completed(void)
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index 284dad1..e65d066 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -35,6 +35,16 @@ extern void rcu_note_context_switch(int cpu);
extern int rcu_needs_cpu(int cpu);
extern void rcu_cpu_stall_reset(void);
+/*
+ * Note a virtualization-based context switch. This is simply a
+ * wrapper around rcu_note_context_switch(), which allows TINY_RCU
+ * to save a few bytes.
+ */
+static inline void rcu_virt_note_context_switch(int cpu)
+{
+ rcu_note_context_switch(cpu);
+}
+
#ifdef CONFIG_TREE_PREEMPT_RCU
extern void exit_rcu(void);
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index b2fe2a2..54ff7eb 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -157,6 +157,7 @@ void rcu_note_context_switch(int cpu)
rcu_sched_qs(cpu);
rcu_preempt_note_context_switch(cpu);
}
+EXPORT_SYMBOL_GPL(rcu_note_context_switch);
#ifdef CONFIG_NO_HZ
DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = {
--
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