diff options
| -rw-r--r-- | kernel/cgroup/rstat.c | 16 |
1 files changed, 13 insertions, 3 deletions
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c index 339366e257d4..a4901e20735a 100644 --- a/kernel/cgroup/rstat.c +++ b/kernel/cgroup/rstat.c @@ -28,9 +28,12 @@ void cgroup_rstat_updated(struct cgroup *cgrp, int cpu) unsigned long flags; /* - * Speculative already-on-list test. This may race leading to - * temporary inaccuracies, which is fine. - * + * Paired with the one in cgroup_rstat_cpu_pop_upated(). Either we + * see NULL updated_next or they see our updated stat. + */ + smp_mb(); + + /* * Because @parent's updated_children is terminated with @parent * instead of NULL, we can tell whether @cgrp is on the list by * testing the next pointer for NULL. @@ -126,6 +129,13 @@ static struct cgroup *cgroup_rstat_cpu_pop_updated(struct cgroup *pos, *nextp = rstatc->updated_next; rstatc->updated_next = NULL; + + /* + * Paired with the one in cgroup_rstat_cpu_updated(). + * Either they see NULL updated_next or we see their + * updated stat. + */ + smp_mb(); } return pos; |