[Devel] [PATCH v3 14/16] slub: slub-specific propagation changes.

[Glauber Costa]

When a parent cache changes a sysfs attr, we need to propagate that to
the children as well. For that, we unfortunately need to tap into the
slub core.

Signed-off-by: Glauber Costa <glommer at parallels.com>
CC: Christoph Lameter <cl at linux.com>
CC: Pekka Enberg <penberg at cs.helsinki.fi>
CC: Michal Hocko <mhocko at suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu at jp.fujitsu.com>
CC: Johannes Weiner <hannes at cmpxchg.org>
CC: Suleiman Souhlal <suleiman at google.com>
---
 mm/slub.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/mm/slub.c b/mm/slub.c
index f90f612..0b68d15 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -5174,6 +5174,10 @@ static ssize_t slab_attr_store(struct kobject *kobj,
 	struct slab_attribute *attribute;
 	struct kmem_cache *s;
 	int err;
+#ifdef CONFIG_MEMCG_KMEM
+	struct kmem_cache *c;
+	struct mem_cgroup_cache_params *p;
+#endif
 
 	attribute = to_slab_attr(attr);
 	s = to_slab(kobj);
@@ -5182,7 +5186,19 @@ static ssize_t slab_attr_store(struct kobject *kobj,
 		return -EIO;
 
 	err = attribute->store(s, buf, len);
+#ifdef CONFIG_MEMCG_KMEM
+	if (slab_state < FULL)
+		return err;
 
+	if ((err < 0) || (s->memcg_params.id == -1))
+		return err;
+
+	list_for_each_entry(p, &s->memcg_params.sibling_list, sibling_list) {
+		c = container_of(p, struct kmem_cache, memcg_params);
+		/* return value determined by the parent cache only */
+		attribute->store(c, buf, len);
+	}
+#endif
 	return err;
 }
 
-- 
1.7.11.4