[PATCH tip/core/rcu 08/22] rcu: Move rcu_barrier_completion to rcu_state structure

Paul E. McKenney
2012-06-22T15:26:21Z

From: "Paul E. McKenney" <paul.mckenney@linaro.org>

In order to allow each RCU flavor to concurrently execute its
rcu_barrier() function, it is necessary to move the relevant
state to the rcu_state structure. This commit therefore moves the
rcu_barrier_completion global variable to a new ->barrier_completion
field in the rcu_state structure.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
---
kernel/rcutree.c | 9 ++++-----
kernel/rcutree.h | 1 +
2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 592c43f..5e087f9 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -158,7 +158,6 @@ unsigned long rcutorture_vernum;
/* State information for rcu_barrier() and friends. */

static DEFINE_MUTEX(rcu_barrier_mutex);
-static struct completion rcu_barrier_completion;

/*
* Return true if an RCU grace period is in progress. The ACCESS_ONCE()s
@@ -2272,7 +2271,7 @@ static void rcu_barrier_callback(struct rcu_head *rhp)
struct rcu_state *rsp = rdp->rsp;

if (atomic_dec_and_test(&rsp->barrier_cpu_count))
- complete(&rcu_barrier_completion);
+ complete(&rsp->barrier_completion);
}

/*
@@ -2322,7 +2321,7 @@ static void _rcu_barrier(struct rcu_state *rsp)
* 6. Both rcu_barrier_callback() callbacks are invoked, awakening
* us -- but before CPU 1's orphaned callbacks are invoked!!!
*/
- init_completion(&rcu_barrier_completion);
+ init_completion(&rsp->barrier_completion);
atomic_set(&rsp->barrier_cpu_count, 1);
raw_spin_lock_irqsave(&rsp->onofflock, flags);
rsp->rcu_barrier_in_progress = current;
@@ -2372,10 +2371,10 @@ static void _rcu_barrier(struct rcu_state *rsp)
* CPU, and thus each counted, remove the initial count.
*/
if (atomic_dec_and_test(&rsp->barrier_cpu_count))
- complete(&rcu_barrier_completion);
+ complete(&rsp->barrier_completion);

/* Wait for all rcu_barrier_callback() callbacks to be invoked. */
- wait_for_completion(&rcu_barrier_completion);
+ wait_for_completion(&rsp->barrier_completion);

/* Other rcu_barrier() invocations can now safely proceed. */
mutex_unlock(&rcu_barrier_mutex);
diff --git a/kernel/rcutree.h b/kernel/rcutree.h
index e7d29b7..56fb8d4 100644
--- a/kernel/rcutree.h
+++ b/kernel/rcutree.h
@@ -387,6 +387,7 @@ struct rcu_state {
/* Task doing rcu_barrier(), */
/* or NULL if no barrier. */
atomic_t barrier_cpu_count; /* # CPUs waiting on. */
+ struct completion barrier_completion; /* Wake at barrier end. */
raw_spinlock_t fqslock; /* Only one task forcing */
/* quiescent states. */
unsigned long jiffies_force_qs; /* Time at which to invoke */
--
1.7.8