diff options
Diffstat (limited to 'kernel/cgroup/rstat.c')
| -rw-r--r-- | kernel/cgroup/rstat.c | 51 |
1 files changed, 24 insertions, 27 deletions
diff --git a/kernel/cgroup/rstat.c b/kernel/cgroup/rstat.c index 1486768f2318..9d331ba44870 100644 --- a/kernel/cgroup/rstat.c +++ b/kernel/cgroup/rstat.c @@ -35,7 +35,7 @@ void cgroup_rstat_updated(struct cgroup *cgrp, int cpu) * instead of NULL, we can tell whether @cgrp is on the list by * testing the next pointer for NULL. */ - if (cgroup_rstat_cpu(cgrp, cpu)->updated_next) + if (data_race(cgroup_rstat_cpu(cgrp, cpu)->updated_next)) return; raw_spin_lock_irqsave(cpu_lock, flags); @@ -88,6 +88,7 @@ static struct cgroup *cgroup_rstat_cpu_pop_updated(struct cgroup *pos, struct cgroup *root, int cpu) { struct cgroup_rstat_cpu *rstatc; + struct cgroup *parent; if (pos == root) return NULL; @@ -96,10 +97,14 @@ static struct cgroup *cgroup_rstat_cpu_pop_updated(struct cgroup *pos, * We're gonna walk down to the first leaf and visit/remove it. We * can pick whatever unvisited node as the starting point. */ - if (!pos) + if (!pos) { pos = root; - else + /* return NULL if this subtree is not on-list */ + if (!cgroup_rstat_cpu(pos, cpu)->updated_next) + return NULL; + } else { pos = cgroup_parent(pos); + } /* walk down to the first leaf */ while (true) { @@ -115,33 +120,25 @@ static struct cgroup *cgroup_rstat_cpu_pop_updated(struct cgroup *pos, * However, due to the way we traverse, @pos will be the first * child in most cases. The only exception is @root. */ - if (rstatc->updated_next) { - struct cgroup *parent = cgroup_parent(pos); - - if (parent) { - struct cgroup_rstat_cpu *prstatc; - struct cgroup **nextp; - - prstatc = cgroup_rstat_cpu(parent, cpu); - nextp = &prstatc->updated_children; - while (true) { - struct cgroup_rstat_cpu *nrstatc; - - nrstatc = cgroup_rstat_cpu(*nextp, cpu); - if (*nextp == pos) - break; - WARN_ON_ONCE(*nextp == parent); - nextp = &nrstatc->updated_next; - } - *nextp = rstatc->updated_next; - } + parent = cgroup_parent(pos); + if (parent) { + struct cgroup_rstat_cpu *prstatc; + struct cgroup **nextp; - rstatc->updated_next = NULL; - return pos; + prstatc = cgroup_rstat_cpu(parent, cpu); + nextp = &prstatc->updated_children; + while (*nextp != pos) { + struct cgroup_rstat_cpu *nrstatc; + + nrstatc = cgroup_rstat_cpu(*nextp, cpu); + WARN_ON_ONCE(*nextp == parent); + nextp = &nrstatc->updated_next; + } + *nextp = rstatc->updated_next; } - /* only happens for @root */ - return NULL; + rstatc->updated_next = NULL; + return pos; } /* see cgroup_rstat_flush() */ |