From 29ce831000081dd757d3116bf774aafffc4b6b20 Mon Sep 17 00:00:00 2001 From: Gleb Natapov Date: Wed, 4 May 2011 16:31:03 +0300 Subject: [PATCH] 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 Signed-off-by: Paul E. McKenney --- include/linux/rcutiny.h | 8 ++++++++ include/linux/rcutree.h | 10 ++++++++++ kernel/rcutree.c | 1 + 3 files changed, 19 insertions(+) diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 30ebd7c8d874..52b3e0281fd0 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -99,6 +99,14 @@ static inline void rcu_note_context_switch(int cpu) rcu_preempt_note_context_switch(); } +/* + * 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. */ diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index 284dad10c55b..e65d06634dd8 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 b2fe2a273df2..54ff7eb92819 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) = { -- 2.20.1