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Subject[PATCH -mm v3 3/8] memcg: mark caches that belong to offline memcgs as dead
Date
This will be used by the next patches.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
---
include/linux/slab.h | 2 ++
mm/memcontrol.c | 3 +++
mm/slab.h | 25 +++++++++++++++++++++++++
3 files changed, 30 insertions(+)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index d9716fdc8211..d99d5212b815 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -527,6 +527,7 @@ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node)
* @list: list_head for the list of all caches in this memcg
* @root_cache: pointer to the global, root cache, this cache was derived from
* @refcnt: reference counter
+ * @dead: set to true when owner memcg is turned offline
* @unregister_work: worker to destroy the cache
*/
struct memcg_cache_params {
@@ -541,6 +542,7 @@ struct memcg_cache_params {
struct list_head list;
struct kmem_cache *root_cache;
atomic_long_t refcnt;
+ bool dead;
struct work_struct unregister_work;
};
};
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 886b5b414958..8f08044d26a7 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3294,7 +3294,10 @@ static void memcg_unregister_all_caches(struct mem_cgroup *memcg)
mutex_lock(&memcg_slab_mutex);
list_for_each_entry_safe(params, tmp, &memcg->memcg_slab_caches, list) {
cachep = memcg_params_to_cache(params);
+
+ memcg_cache_mark_dead(cachep);
kmem_cache_shrink(cachep);
+
if (atomic_long_dec_and_test(&cachep->memcg_params->refcnt))
memcg_unregister_cache(cachep);
}
diff --git a/mm/slab.h b/mm/slab.h
index 961a3fb1f5a2..2af5a0bc00a4 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -121,6 +121,26 @@ static inline bool is_root_cache(struct kmem_cache *s)
return !s->memcg_params || s->memcg_params->is_root_cache;
}

+static inline bool memcg_cache_dead(struct kmem_cache *s)
+{
+ if (is_root_cache(s))
+ return false;
+
+ /*
+ * Since this function can be called without holding any locks, it
+ * needs a barrier here to guarantee the read won't be reordered.
+ */
+ smp_rmb();
+ return s->memcg_params->dead;
+}
+
+static inline void memcg_cache_mark_dead(struct kmem_cache *s)
+{
+ BUG_ON(is_root_cache(s));
+ s->memcg_params->dead = true;
+ smp_wmb(); /* matches rmb in memcg_cache_dead() */
+}
+
static inline bool slab_equal_or_root(struct kmem_cache *s,
struct kmem_cache *p)
{
@@ -203,6 +223,11 @@ static inline bool is_root_cache(struct kmem_cache *s)
return true;
}

+static inline bool memcg_cache_dead(struct kmem_cache *s)
+{
+ return false;
+}
+
static inline bool slab_equal_or_root(struct kmem_cache *s,
struct kmem_cache *p)
{
--
1.7.10.4


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