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-rw-r--r--mm/memcontrol.c49
1 files changed, 47 insertions, 2 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 270a367..4b68ec2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2772,6 +2772,8 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *memcg,
memcg_check_events(memcg, page);
}
+static DEFINE_MUTEX(set_limit_mutex);
+
#ifdef CONFIG_MEMCG_KMEM
static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg)
{
@@ -3176,6 +3178,51 @@ out:
return new_cachep;
}
+void kmem_cache_destroy_memcg_children(struct kmem_cache *s)
+{
+ struct kmem_cache *c;
+ int i;
+
+ if (!s->memcg_params)
+ return;
+ if (!s->memcg_params->is_root_cache)
+ return;
+
+ /*
+ * If the cache is being destroyed, we trust that there is no one else
+ * requesting objects from it. Even if there are, the sanity checks in
+ * kmem_cache_destroy should caught this ill-case.
+ *
+ * Still, we don't want anyone else freeing memcg_caches under our
+ * noses, which can happen if a new memcg comes to life. As usual,
+ * we'll take the set_limit_mutex to protect ourselves against this.
+ */
+ mutex_lock(&set_limit_mutex);
+ for (i = 0; i < memcg_limited_groups_array_size; i++) {
+ c = s->memcg_params->memcg_caches[i];
+ if (!c)
+ continue;
+
+ /*
+ * We will now manually delete the caches, so to avoid races
+ * we need to cancel all pending destruction workers and
+ * proceed with destruction ourselves.
+ *
+ * kmem_cache_destroy() will call kmem_cache_shrink internally,
+ * and that could spawn the workers again: it is likely that
+ * the cache still have active pages until this very moment.
+ * This would lead us back to mem_cgroup_destroy_cache.
+ *
+ * But that will not execute at all if the "dead" flag is not
+ * set, so flip it down to guarantee we are in control.
+ */
+ c->memcg_params->dead = false;
+ cancel_delayed_work_sync(&c->memcg_params->destroy);
+ kmem_cache_destroy(c);
+ }
+ mutex_unlock(&set_limit_mutex);
+}
+
struct create_work {
struct mem_cgroup *memcg;
struct kmem_cache *cachep;
@@ -4284,8 +4331,6 @@ void mem_cgroup_print_bad_page(struct page *page)
}
#endif
-static DEFINE_MUTEX(set_limit_mutex);
-
static int mem_cgroup_resize_limit(struct mem_cgroup *memcg,
unsigned long long val)
{
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