diff options
| author | Roman Gushchin <guro@fb.com> | 2019-07-11 20:56:31 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-07-12 11:05:44 -0700 |
| commit | 4d96ba3530750fae3f3f01150adfecde96157815 (patch) | |
| tree | 07ecb2d8f21bff7471ed9fd5c46b4a45fa6dcf5b /mm/list_lru.c | |
| parent | f0a3a24b532d9a7e56a33c5112b2a212ed6ec580 (diff) | |
mm: memcg/slab: stop setting page->mem_cgroup pointer for slab pages
Every slab page charged to a non-root memory cgroup has a pointer to the
memory cgroup and holds a reference to it, which protects a non-empty
memory cgroup from being released. At the same time the page has a
pointer to the corresponding kmem_cache, and also hold a reference to the
kmem_cache. And kmem_cache by itself holds a reference to the cgroup.
So there is clearly some redundancy, which allows to stop setting the
page->mem_cgroup pointer and rely on getting memcg pointer indirectly via
kmem_cache. Further it will allow to change this pointer easier, without
a need to go over all charged pages.
So let's stop setting page->mem_cgroup pointer for slab pages, and stop
using the css refcounter directly for protecting the memory cgroup from
going away. Instead rely on kmem_cache as an intermediate object.
Make sure that vmstats and shrinker lists are working as previously, as
well as /proc/kpagecgroup interface.
Link: http://lkml.kernel.org/r/20190611231813.3148843-10-guro@fb.com
Signed-off-by: Roman Gushchin <guro@fb.com>
Acked-by: Vladimir Davydov <vdavydov.dev@gmail.com>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Waiman Long <longman@redhat.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Andrei Vagin <avagin@gmail.com>
Cc: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/list_lru.c')
| -rw-r--r-- | mm/list_lru.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/mm/list_lru.c b/mm/list_lru.c index 927d85be32f6..0f1f6b06b7f3 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -12,6 +12,7 @@ #include <linux/slab.h> #include <linux/mutex.h> #include <linux/memcontrol.h> +#include "slab.h" #ifdef CONFIG_MEMCG_KMEM static LIST_HEAD(list_lrus); @@ -63,7 +64,7 @@ static __always_inline struct mem_cgroup *mem_cgroup_from_kmem(void *ptr) if (!memcg_kmem_enabled()) return NULL; page = virt_to_head_page(ptr); - return page->mem_cgroup; + return memcg_from_slab_page(page); } static inline struct list_lru_one * |