[PATCH tip/core/rcu 10/10] rcu: Account for rcu_all_qs() in cond_resched()

From: Paul E. McKenney
Date: Fri Dec 01 2017 - 14:22:04 EST


If cond_resched() returns false, then it has already invoked
rcu_all_qs(). This is also invoked (now redundantly) by
rcu_note_voluntary_context_switch(). This commit therefore changes
cond_resched_rcu_qs() to invoke rcu_note_voluntary_context_switch_lite()
instead of rcu_note_voluntary_context_switch() to avoid the redundant
invocation of rcu_all_qs().

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
include/linux/rcupdate.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index a6ddc42f87a5..7bd8b5a6db10 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -197,7 +197,7 @@ static inline void exit_tasks_rcu_finish(void) { }
#define cond_resched_rcu_qs() \
do { \
if (!cond_resched()) \
- rcu_note_voluntary_context_switch(current); \
+ rcu_note_voluntary_context_switch_lite(current); \
} while (0)

/*
--
2.5.2