From 33a690c45b202e4c6483bfd1d93ad8d0f51df2ca Mon Sep 17 00:00:00 2001 From: Vladimir Davydov Date: Thu, 9 Oct 2014 15:28:43 -0700 Subject: [PATCH] memcg: move memcg_{alloc,free}_cache_params to slab_common.c The only reason why they live in memcontrol.c is that we get/put css reference to the owner memory cgroup in them. However, we can do that in memcg_{un,}register_cache. OTOH, there are several reasons to move them to slab_common.c. First, I think that the less public interface functions we have in memcontrol.h the better. Since the functions I move don't depend on memcontrol, I think it's worth making them private to slab, especially taking into account that the arrays are defined on the slab's side too. Second, the way how per-memcg arrays are updated looks rather awkward: it proceeds from memcontrol.c (__memcg_activate_kmem) to slab_common.c (memcg_update_all_caches) and back to memcontrol.c again (memcg_update_array_size). In the following patches I move the function relocating the arrays (memcg_update_array_size) to slab_common.c and therefore get rid this circular call path. I think we should have the cache allocation stuff in the same place where we have relocation, because it's easier to follow the code then. So I move arrays alloc/free functions to slab_common.c too. The third point isn't obvious. I'm going to make the list_lru structure per-memcg to allow targeted kmem reclaim. That means we will have per-memcg arrays in list_lrus too. It turns out that it's much easier to update these arrays in list_lru.c rather than in memcontrol.c, because all the stuff we need is defined there. This patch makes memcg caches arrays allocation path conform that of the upcoming list_lru. So let's move these functions to slab_common.c and make them static. Signed-off-by: Vladimir Davydov Acked-by: Johannes Weiner Acked-by: Michal Hocko Cc: Christoph Lameter Cc: Glauber Costa Cc: Joonsoo Kim Cc: David Rientjes Cc: Pekka Enberg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 14 ------------ mm/memcontrol.c | 41 ++++------------------------------- mm/slab_common.c | 44 +++++++++++++++++++++++++++++++++++++- 3 files changed, 47 insertions(+), 52 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index e0752d204d9e..4d17242eeff7 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -440,10 +440,6 @@ void __memcg_kmem_uncharge_pages(struct page *page, int order); int memcg_cache_id(struct mem_cgroup *memcg); -int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s, - struct kmem_cache *root_cache); -void memcg_free_cache_params(struct kmem_cache *s); - int memcg_update_cache_size(struct kmem_cache *s, int num_groups); void memcg_update_array_size(int num_groups); @@ -574,16 +570,6 @@ static inline int memcg_cache_id(struct mem_cgroup *memcg) return -1; } -static inline int memcg_alloc_cache_params(struct mem_cgroup *memcg, - struct kmem_cache *s, struct kmem_cache *root_cache) -{ - return 0; -} - -static inline void memcg_free_cache_params(struct kmem_cache *s) -{ -} - static inline struct kmem_cache * memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp) { diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 28928ce9b07f..865e87c014d6 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2984,43 +2984,6 @@ int memcg_update_cache_size(struct kmem_cache *s, int num_groups) return 0; } -int memcg_alloc_cache_params(struct mem_cgroup *memcg, struct kmem_cache *s, - struct kmem_cache *root_cache) -{ - size_t size; - - if (!memcg_kmem_enabled()) - return 0; - - 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) - return -ENOMEM; - - if (memcg) { - s->memcg_params->memcg = memcg; - s->memcg_params->root_cache = root_cache; - css_get(&memcg->css); - } else - s->memcg_params->is_root_cache = true; - - return 0; -} - -void memcg_free_cache_params(struct kmem_cache *s) -{ - if (!s->memcg_params) - return; - if (!s->memcg_params->is_root_cache) - css_put(&s->memcg_params->memcg->css); - kfree(s->memcg_params); -} - static void memcg_register_cache(struct mem_cgroup *memcg, struct kmem_cache *root_cache) { @@ -3051,6 +3014,7 @@ static void memcg_register_cache(struct mem_cgroup *memcg, if (!cachep) return; + css_get(&memcg->css); list_add(&cachep->memcg_params->list, &memcg->memcg_slab_caches); /* @@ -3084,6 +3048,9 @@ static void memcg_unregister_cache(struct kmem_cache *cachep) list_del(&cachep->memcg_params->list); kmem_cache_destroy(cachep); + + /* drop the reference taken in memcg_register_cache */ + css_put(&memcg->css); } /* diff --git a/mm/slab_common.c b/mm/slab_common.c index f206cb10a544..c2a8661f8b81 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -116,6 +116,38 @@ static inline int kmem_cache_sanity_check(const char *name, size_t size) #endif #ifdef CONFIG_MEMCG_KMEM +static int memcg_alloc_cache_params(struct mem_cgroup *memcg, + struct kmem_cache *s, struct kmem_cache *root_cache) +{ + size_t size; + + if (!memcg_kmem_enabled()) + return 0; + + 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) + return -ENOMEM; + + if (memcg) { + s->memcg_params->memcg = memcg; + s->memcg_params->root_cache = root_cache; + } else + s->memcg_params->is_root_cache = true; + + return 0; +} + +static void memcg_free_cache_params(struct kmem_cache *s) +{ + kfree(s->memcg_params); +} + int memcg_update_all_caches(int num_memcgs) { struct kmem_cache *s; @@ -141,7 +173,17 @@ int memcg_update_all_caches(int num_memcgs) mutex_unlock(&slab_mutex); return ret; } -#endif +#else +static inline int memcg_alloc_cache_params(struct mem_cgroup *memcg, + struct kmem_cache *s, struct kmem_cache *root_cache) +{ + return 0; +} + +static inline void memcg_free_cache_params(struct kmem_cache *s) +{ +} +#endif /* CONFIG_MEMCG_KMEM */ /* * Find a mergeable slab cache -- GitLab