diff options
| -rw-r--r-- | mm/memcontrol.c | 52 |
1 files changed, 25 insertions, 27 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 408a5c75d77d..614d0d9c0deb 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -1116,7 +1116,6 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, rcu_read_lock(); while (!memcg) { struct mem_cgroup_reclaim_iter *uninitialized_var(iter); - struct cgroup_subsys_state *css = NULL; if (reclaim) { int nid = zone_to_nid(reclaim->zone); @@ -1159,51 +1158,50 @@ struct mem_cgroup *mem_cgroup_iter(struct mem_cgroup *root, * explicit visit. */ if (!last_visited) { - css = &root->css; + memcg = root; } else { struct cgroup *prev_cgroup, *next_cgroup; prev_cgroup = (last_visited == root) ? NULL : last_visited->css.cgroup; - next_cgroup = cgroup_next_descendant_pre(prev_cgroup, - root->css.cgroup); - if (next_cgroup) - css = cgroup_subsys_state(next_cgroup, - mem_cgroup_subsys_id); - } +skip_node: + next_cgroup = cgroup_next_descendant_pre( + prev_cgroup, root->css.cgroup); - /* - * Even if we found a group we have to make sure it is alive. - * css && !memcg means that the groups should be skipped and - * we should continue the tree walk. - * last_visited css is safe to use because it is protected by - * css_get and the tree walk is rcu safe. - */ - if (css == &root->css || (css && css_tryget(css))) - memcg = mem_cgroup_from_css(css); + /* + * Even if we found a group we have to make sure it is + * alive. css && !memcg means that the groups should be + * skipped and we should continue the tree walk. + * last_visited css is safe to use because it is + * protected by css_get and the tree walk is rcu safe. + */ + if (next_cgroup) { + struct mem_cgroup *mem = mem_cgroup_from_cont( + next_cgroup); + if (css_tryget(&mem->css)) + memcg = mem; + else { + prev_cgroup = next_cgroup; + goto skip_node; + } + } + } if (reclaim) { - struct mem_cgroup *curr = memcg; - if (last_visited) css_put(&last_visited->css); - if (css && !memcg) - curr = mem_cgroup_from_css(css); - - iter->last_visited = curr; + iter->last_visited = memcg; smp_wmb(); iter->last_dead_count = dead_count; - if (!css) + if (!memcg) iter->generation++; else if (!prev && memcg) reclaim->generation = iter->generation; - } else if (css && !memcg) { - last_visited = mem_cgroup_from_css(css); } - if (prev && !css) + if (prev && !memcg) goto out_unlock; } out_unlock: |