| [PATCH v4 14/19] memcg/sl[au]b Track all the memcg children of a kmem_cache. [message #48325 is a reply to message #48308] |
Fri, 12 October 2012 13:41   |
Glauber Costa
Messages: 916
Registered: October 2011
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Senior Member |
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This enables us to remove all the children of a kmem_cache being
destroyed, if for example the kernel module it's being used in
gets unloaded. Otherwise, the children will still point to the
destroyed parent.
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
Signed-off-by: Glauber Costa <glommer@parallels.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
CC: Tejun Heo <tj@kernel.org>
---
include/linux/memcontrol.h | 6 ++++++
mm/memcontrol.c | 32 ++++++++++++++++++++++++++++++--
mm/slab_common.c | 3 +++
3 files changed, 39 insertions(+), 2 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 9ac12cb..6c8156b 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -427,6 +427,7 @@ struct kmem_cache *
__memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp);
void mem_cgroup_destroy_cache(struct kmem_cache *cachep);
+void kmem_cache_destroy_memcg_children(struct kmem_cache *s);
/**
* memcg_kmem_newpage_charge: verify if a new kmem allocation is allowed.
@@ -578,6 +579,11 @@ memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
{
return cachep;
}
+
+
+static inline void kmem_cache_destroy_memcg_children(struct kmem_cache *s)
+{
+}
#endif /* CONFIG_MEMCG_KMEM */
#endif /* _LINUX_MEMCONTROL_H */
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index f744305..8cf8b4d 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2716,6 +2716,8 @@ 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)
{
@@ -3093,6 +3095,34 @@ 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)
+ kmem_cache_destroy(c);
+ }
+ mutex_unlock(&set_limit_mutex);
+}
+
struct create_work {
struct mem_cgroup *memcg;
struct kmem_cache *cachep;
@@ -4189,8 +4219,6 @@ 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)
{
diff --git a/mm/slab_common.c b/mm/slab_common.c
index fcf59d7..c02faf5 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -214,6 +214,9 @@ EXPORT_SYMBOL(kmem_cache_create);
void kmem_cache_destroy(struct kmem_cache *s)
{
+ /* Destroy all the children caches if we aren't a memcg cache */
+ kmem_cache_destroy_memcg_children(s);
+
get_online_cpus();
mutex_lock(&slab_mutex);
s->refcount--;
--
1.7.11.4
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