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| author | Joel Fernandes (Google) <joel@joelfernandes.org> | 2020-10-14 18:21:53 -0400 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2021-01-06 16:24:19 -0800 |
| commit | 68804cf1c905ce227e4e1d0bc252c216811c59fd (patch) | |
| tree | fa911f459c48d65bd374da8d18e539bf15e60647 /kernel/rcu | |
| parent | ae5c2341ed3987bd434ed495bd4f3d8b2bc3e623 (diff) | |
| download | linux-68804cf1c905ce227e4e1d0bc252c216811c59fd.tar.bz2 | |
rcu/tree: segcblist: Remove redundant smp_mb()s
The full memory barriers in rcu_segcblist_enqueue() and in rcu_do_batch()
are not needed because rcu_segcblist_add_len(), and thus also
rcu_segcblist_inc_len(), already includes a memory barrier *before*
and *after* the length of the list is updated.
This commit therefore removes these redundant smp_mb() invocations.
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/rcu_segcblist.c | 1 | ||||
| -rw-r--r-- | kernel/rcu/tree.c | 1 |
2 files changed, 0 insertions, 2 deletions
diff --git a/kernel/rcu/rcu_segcblist.c b/kernel/rcu/rcu_segcblist.c index 777780447887..1e80a0a9036a 100644 --- a/kernel/rcu/rcu_segcblist.c +++ b/kernel/rcu/rcu_segcblist.c @@ -327,7 +327,6 @@ void rcu_segcblist_enqueue(struct rcu_segcblist *rsclp, struct rcu_head *rhp) { rcu_segcblist_inc_len(rsclp); - smp_mb(); /* Ensure counts are updated before callback is enqueued. */ rcu_segcblist_inc_seglen(rsclp, RCU_NEXT_TAIL); rhp->next = NULL; WRITE_ONCE(*rsclp->tails[RCU_NEXT_TAIL], rhp); diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index cc6f379c7ddf..b0fb654cba80 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2523,7 +2523,6 @@ static void rcu_do_batch(struct rcu_data *rdp) /* Update counts and requeue any remaining callbacks. */ rcu_segcblist_insert_done_cbs(&rdp->cblist, &rcl); - smp_mb(); /* List handling before counting for rcu_barrier(). */ rcu_segcblist_add_len(&rdp->cblist, -count); /* Reinstate batch limit if we have worked down the excess. */ |