On our way to share slab pages between multiple memory cgroups let's make sure we don't use kmem_cache.memcg_params.memcg pointer to determine memcg ownership of a slab object/page.
Let's transform memcg_from_slab_page() into memcg_from_slab_obj(), which relies on memcg ownership data stored in page->mem_cgroup_vec. Delete mem_cgroup_from_kmem() and use memcg_from_slab_obj() instead. Note: memcg_from_slab_obj() returns NULL if slab obj belongs to the root cgroup, so remove the redundant check in __mod_lruvec_slab_state(). Signed-off-by: Roman Gushchin <[email protected]> --- mm/list_lru.c | 12 +----------- mm/memcontrol.c | 9 ++++----- mm/slab.h | 21 +++++++++++++-------- 3 files changed, 18 insertions(+), 24 deletions(-) diff --git a/mm/list_lru.c b/mm/list_lru.c index 0f1f6b06b7f3..4f9d791b802c 100644 --- a/mm/list_lru.c +++ b/mm/list_lru.c @@ -57,16 +57,6 @@ list_lru_from_memcg_idx(struct list_lru_node *nlru, int idx) return &nlru->lru; } -static __always_inline struct mem_cgroup *mem_cgroup_from_kmem(void *ptr) -{ - struct page *page; - - if (!memcg_kmem_enabled()) - return NULL; - page = virt_to_head_page(ptr); - return memcg_from_slab_page(page); -} - static inline struct list_lru_one * list_lru_from_kmem(struct list_lru_node *nlru, void *ptr, struct mem_cgroup **memcg_ptr) @@ -77,7 +67,7 @@ list_lru_from_kmem(struct list_lru_node *nlru, void *ptr, if (!nlru->memcg_lrus) goto out; - memcg = mem_cgroup_from_kmem(ptr); + memcg = memcg_from_slab_obj(ptr); if (!memcg) goto out; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 8a753a336efd..1982b14d6e6f 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -548,7 +548,7 @@ ino_t page_cgroup_ino(struct page *page) rcu_read_lock(); if (PageHead(page) && PageSlab(page)) - memcg = memcg_from_slab_page(page); + memcg = root_mem_cgroup; else memcg = READ_ONCE(page->mem_cgroup); while (memcg && !(memcg->css.flags & CSS_ONLINE)) @@ -852,16 +852,15 @@ void __mod_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx, void __mod_lruvec_slab_state(void *p, enum node_stat_item idx, int val) { - struct page *page = virt_to_head_page(p); - pg_data_t *pgdat = page_pgdat(page); + pg_data_t *pgdat = page_pgdat(virt_to_page(p)); struct mem_cgroup *memcg; struct lruvec *lruvec; rcu_read_lock(); - memcg = memcg_from_slab_page(page); + memcg = memcg_from_slab_obj(p); /* Untracked pages have no memcg, no lruvec. Update only the node */ - if (!memcg || memcg == root_mem_cgroup) { + if (!memcg) { __mod_node_page_state(pgdat, idx, val); } else { lruvec = mem_cgroup_lruvec(pgdat, memcg); diff --git a/mm/slab.h b/mm/slab.h index 0f2f712de77a..a6330065d434 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -329,15 +329,20 @@ static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s) * The kmem_cache can be reparented asynchronously. The caller must ensure * the memcg lifetime, e.g. by taking rcu_read_lock() or cgroup_mutex. */ -static inline struct mem_cgroup *memcg_from_slab_page(struct page *page) +static inline struct mem_cgroup *memcg_from_slab_obj(void *ptr) { - struct kmem_cache *s; - - s = READ_ONCE(page->slab_cache); - if (s && !is_root_cache(s)) - return READ_ONCE(s->memcg_params.memcg); + struct mem_cgroup_ptr *memcg_ptr; + struct page *page; + unsigned int off; - return NULL; + if (!memcg_kmem_enabled()) + return NULL; + page = virt_to_head_page(ptr); + if (is_root_cache(page->slab_cache)) + return NULL; + off = obj_to_index(page->slab_cache, page, ptr); + memcg_ptr = page->mem_cgroup_vec[off]; + return memcg_ptr->memcg; } static inline int memcg_alloc_page_memcg_vec(struct page *page, gfp_t gfp, @@ -464,7 +469,7 @@ static inline struct kmem_cache *memcg_root_cache(struct kmem_cache *s) return s; } -static inline struct mem_cgroup *memcg_from_slab_page(struct page *page) +static inline struct mem_cgroup *memcg_from_slab_obj(void *ptr) { return NULL; } -- 2.21.0
