diff options
| -rw-r--r-- | mm/memcontrol.c | 86 |
1 files changed, 70 insertions, 16 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 85599662bd90..95d6c256b54c 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -246,7 +246,10 @@ struct mem_cgroup { * Should the accounting and control be hierarchical, per subtree? */ bool use_hierarchy; - atomic_t oom_lock; + + bool oom_lock; + atomic_t under_oom; + atomic_t refcnt; int swappiness; @@ -1722,37 +1725,83 @@ static int mem_cgroup_hierarchical_reclaim(struct mem_cgroup *root_mem, /* * Check OOM-Killer is already running under our hierarchy. * If someone is running, return false. + * Has to be called with memcg_oom_mutex */ static bool mem_cgroup_oom_lock(struct mem_cgroup *mem) { - int x, lock_count = 0; - struct mem_cgroup *iter; + int lock_count = -1; + struct mem_cgroup *iter, *failed = NULL; + bool cond = true; - for_each_mem_cgroup_tree(iter, mem) { - x = atomic_inc_return(&iter->oom_lock); - lock_count = max(x, lock_count); + for_each_mem_cgroup_tree_cond(iter, mem, cond) { + bool locked = iter->oom_lock; + + iter->oom_lock = true; + if (lock_count == -1) + lock_count = iter->oom_lock; + else if (lock_count != locked) { + /* + * this subtree of our hierarchy is already locked + * so we cannot give a lock. + */ + lock_count = 0; + failed = iter; + cond = false; + } } - if (lock_count == 1) - return true; - return false; + if (!failed) + goto done; + + /* + * OK, we failed to lock the whole subtree so we have to clean up + * what we set up to the failing subtree + */ + cond = true; + for_each_mem_cgroup_tree_cond(iter, mem, cond) { + if (iter == failed) { + cond = false; + continue; + } + iter->oom_lock = false; + } +done: + return lock_count; } +/* + * Has to be called with memcg_oom_mutex + */ static int mem_cgroup_oom_unlock(struct mem_cgroup *mem) { struct mem_cgroup *iter; + for_each_mem_cgroup_tree(iter, mem) + iter->oom_lock = false; + return 0; +} + +static void mem_cgroup_mark_under_oom(struct mem_cgroup *mem) +{ + struct mem_cgroup *iter; + + for_each_mem_cgroup_tree(iter, mem) + atomic_inc(&iter->under_oom); +} + +static void mem_cgroup_unmark_under_oom(struct mem_cgroup *mem) +{ + struct mem_cgroup *iter; + /* * When a new child is created while the hierarchy is under oom, * mem_cgroup_oom_lock() may not be called. We have to use * atomic_add_unless() here. */ for_each_mem_cgroup_tree(iter, mem) - atomic_add_unless(&iter->oom_lock, -1, 0); - return 0; + atomic_add_unless(&iter->under_oom, -1, 0); } - static DEFINE_MUTEX(memcg_oom_mutex); static DECLARE_WAIT_QUEUE_HEAD(memcg_oom_waitq); @@ -1794,7 +1843,7 @@ static void memcg_wakeup_oom(struct mem_cgroup *mem) static void memcg_oom_recover(struct mem_cgroup *mem) { - if (mem && atomic_read(&mem->oom_lock)) + if (mem && atomic_read(&mem->under_oom)) memcg_wakeup_oom(mem); } @@ -1812,6 +1861,8 @@ bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask) owait.wait.private = current; INIT_LIST_HEAD(&owait.wait.task_list); need_to_kill = true; + mem_cgroup_mark_under_oom(mem); + /* At first, try to OOM lock hierarchy under mem.*/ mutex_lock(&memcg_oom_mutex); locked = mem_cgroup_oom_lock(mem); @@ -1835,10 +1886,13 @@ bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask) finish_wait(&memcg_oom_waitq, &owait.wait); } mutex_lock(&memcg_oom_mutex); - mem_cgroup_oom_unlock(mem); + if (locked) + mem_cgroup_oom_unlock(mem); memcg_wakeup_oom(mem); mutex_unlock(&memcg_oom_mutex); + mem_cgroup_unmark_under_oom(mem); + if (test_thread_flag(TIF_MEMDIE) || fatal_signal_pending(current)) return false; /* Give chance to dying process */ @@ -4505,7 +4559,7 @@ static int mem_cgroup_oom_register_event(struct cgroup *cgrp, list_add(&event->list, &memcg->oom_notify); /* already in OOM ? */ - if (atomic_read(&memcg->oom_lock)) + if (atomic_read(&memcg->under_oom)) eventfd_signal(eventfd, 1); mutex_unlock(&memcg_oom_mutex); @@ -4540,7 +4594,7 @@ static int mem_cgroup_oom_control_read(struct cgroup *cgrp, cb->fill(cb, "oom_kill_disable", mem->oom_kill_disable); - if (atomic_read(&mem->oom_lock)) + if (atomic_read(&mem->under_oom)) cb->fill(cb, "under_oom", 1); else cb->fill(cb, "under_oom", 0); |