While growing per memcg caches arrays, we jump between memcontrol.c and
slab_common.c in a weird way:
memcg_alloc_cache_id - memcontrol.c
memcg_update_all_caches - slab_common.c
memcg_update_cache_size - memcontrol.c
There's absolutely no reason why memcg_update_cache_size can't live on
the slab's side though. So let's move it there and settle it comfortably
amid per-memcg cache allocation functions.
Besides, this patch cleans this function up a bit, removing all the
useless comments from it, and renames it to memcg_update_cache_params to
conform to memcg_alloc/free_cache_params, which we already have in
slab_common.c.
Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 1 -
mm/memcontrol.c | 49 --------------------------------------------
mm/slab_common.c | 30 +++++++++++++++++++++++++--
3 files changed, 28 insertions(+), 52 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 4d17242eeff7..19df5d857411 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -440,7 +440,6 @@ void __memcg_kmem_uncharge_pages(struct page *page, int order);
int memcg_cache_id(struct mem_cgroup *memcg);
-int memcg_update_cache_size(struct kmem_cache *s, int num_groups);
void memcg_update_array_size(int num_groups);
struct kmem_cache *
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 55d131645b45..1ec22bf380d0 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2944,55 +2944,6 @@ void memcg_update_array_size(int num)
memcg_limited_groups_array_size = num;
}
-int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
-{
- struct memcg_cache_params *cur_params = s->memcg_params;
- struct memcg_cache_params *new_params;
- size_t size;
- int i;
-
- VM_BUG_ON(!is_root_cache(s));
-
- size = num_groups * sizeof(void *);
- size += offsetof(struct memcg_cache_params, memcg_caches);
-
- new_params = kzalloc(size, GFP_KERNEL);
- if (!new_params)
- return -ENOMEM;
-
- new_params->is_root_cache = true;
-
- /*
- * There is the chance it will be bigger than
- * memcg_limited_groups_array_size, if we failed an allocation
- * in a cache, in which case all caches updated before it, will
- * have a bigger array.
- *
- * But if that is the case, the data after
- * memcg_limited_groups_array_size is certainly unused
- */
- for (i = 0; i < memcg_limited_groups_array_size; i++) {
- if (!cur_params->memcg_caches[i])
- continue;
- new_params->memcg_caches[i] =
- cur_params->memcg_caches[i];
- }
-
- /*
- * Ideally, we would wait until all caches succeed, and only
- * then free the old one. But this is not worth the extra
- * pointer per-cache we'd have to have for this.
- *
- * It is not a big deal if some caches are left with a size
- * bigger than the others. And all updates will reset this
- * anyway.
- */
- rcu_assign_pointer(s->memcg_params, new_params);
- if (cur_params)
- kfree_rcu(cur_params, rcu_head);
- return 0;
-}
-
static void memcg_register_cache(struct mem_cgroup *memcg,
struct kmem_cache *root_cache)
{
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 9c29ba792368..800314e2a075 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -120,6 +120,33 @@ static void memcg_free_cache_params(struct kmem_cache *s)
kfree(s->memcg_params);
}
+static int memcg_update_cache_params(struct kmem_cache *s, int num_memcgs)
+{
+ int size;
+ struct memcg_cache_params *new_params, *cur_params;
+
+ BUG_ON(!is_root_cache(s));
+
+ size = offsetof(struct memcg_cache_params, memcg_caches);
+ size += num_memcgs * sizeof(void *);
+
+ new_params = kzalloc(size, GFP_KERNEL);
+ if (!new_params)
+ return -ENOMEM;
+
+ cur_params = s->memcg_params;
+ memcpy(new_params->memcg_caches, cur_params->memcg_caches,
+ memcg_limited_groups_array_size * sizeof(void *));
+
+ new_params->is_root_cache = true;
+
+ rcu_assign_pointer(s->memcg_params, new_params);
+ if (cur_params)
+ kfree_rcu(cur_params, rcu_head);
+
+ return 0;
+}
+
int memcg_update_all_caches(int num_memcgs)
{
struct kmem_cache *s;
@@ -130,9 +157,8 @@ int memcg_update_all_caches(int num_memcgs)
if (!is_root_cache(s))
continue;
- ret = memcg_update_cache_size(s, num_memcgs);
+ ret = memcg_update_cache_params(s, num_memcgs);
/*
- * See comment in memcontrol.c, memcg_update_cache_size:
* Instead of freeing the memory, we'll just leave the caches
* up to this point in an updated state.
*/
--
1.7.10.4
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