The memcg_cache_params structure contains the common part and the union,
which represents two different types of data: one for root cashes and
another for child caches.
The size of child data is fixed. The size of the memcg_caches array is
calculated in runtime.
Currently the size of memcg_cache_params for root caches is calculated
incorrectly, because it includes the size of parameters for child caches.
ssize_t size = memcg_caches_array_size(num_groups);
size *= sizeof(void *);
size += sizeof(struct memcg_cache_params);
Cc: Glauber Costa <[email protected]>
Cc: Johannes Weiner <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Balbir Singh <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Andrey Vagin <[email protected]>
---
mm/memcontrol.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index c5792a5..d69a10b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3140,7 +3140,7 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
ssize_t size = memcg_caches_array_size(num_groups);
size *= sizeof(void *);
- size += sizeof(struct memcg_cache_params);
+ size += sizeof(offsetof(struct memcg_cache_params, memcg_caches));
s->memcg_params = kzalloc(size, GFP_KERNEL);
if (!s->memcg_params) {
@@ -3183,13 +3183,16 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s,
struct kmem_cache *root_cache)
{
- size_t size = sizeof(struct memcg_cache_params);
+ size_t size;
if (!memcg_kmem_enabled())
return 0;
- if (!memcg)
+ if (!memcg) {
+ size = offsetof(struct memcg_cache_params, memcg_caches);
size += memcg_limited_groups_array_size * sizeof(void *);
+ } else
+ size = sizeof(struct memcg_cache_params);
s->memcg_params = kzalloc(size, GFP_KERNEL);
if (!s->memcg_params)
--
1.8.3.1
On Wed, 14 Aug 2013 14:31:21 +0400 Andrey Vagin <[email protected]> wrote:
> The memcg_cache_params structure contains the common part and the union,
> which represents two different types of data: one for root cashes and
> another for child caches.
>
> The size of child data is fixed. The size of the memcg_caches array is
> calculated in runtime.
>
> Currently the size of memcg_cache_params for root caches is calculated
> incorrectly, because it includes the size of parameters for child caches.
>
> ssize_t size = memcg_caches_array_size(num_groups);
> size *= sizeof(void *);
>
> size += sizeof(struct memcg_cache_params);
>
> ...
>
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -3140,7 +3140,7 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
> ssize_t size = memcg_caches_array_size(num_groups);
>
> size *= sizeof(void *);
> - size += sizeof(struct memcg_cache_params);
> + size += sizeof(offsetof(struct memcg_cache_params, memcg_caches));
This looks wrong. offsetof() returns size_t, so this is equivalent to
size += sizeof(size_t);
> s->memcg_params = kzalloc(size, GFP_KERNEL);
> if (!s->memcg_params) {
> @@ -3183,13 +3183,16 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
> int memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *s,
> struct kmem_cache *root_cache)
> {
> - size_t size = sizeof(struct memcg_cache_params);
> + size_t size;
>
> if (!memcg_kmem_enabled())
> return 0;
>
> - if (!memcg)
> + if (!memcg) {
> + size = offsetof(struct memcg_cache_params, memcg_caches);
> size += memcg_limited_groups_array_size * sizeof(void *);
> + } else
> + size = sizeof(struct memcg_cache_params);
>
> s->memcg_params = kzalloc(size, GFP_KERNEL);
> if (!s->memcg_params)