From 1f458cbf122288b23620ee822e19bcbb76c8d6ec Mon Sep 17 00:00:00 2001 From: Glauber Costa Date: Tue, 18 Dec 2012 14:22:50 -0800 Subject: memcg: destroy memcg caches Implement destruction of memcg caches. Right now, only caches where our reference counter is the last remaining are deleted. If there are any other reference counters around, we just leave the caches lying around until they go away. When that happens, a destruction function is called from the cache code. Caches are only destroyed in process context, so we queue them up for later processing in the general case. Signed-off-by: Glauber Costa Cc: Christoph Lameter Cc: David Rientjes Cc: Frederic Weisbecker Cc: Greg Thelen Cc: Johannes Weiner Cc: JoonSoo Kim Cc: KAMEZAWA Hiroyuki Cc: Mel Gorman Cc: Michal Hocko Cc: Pekka Enberg Cc: Rik van Riel Cc: Suleiman Souhlal Cc: Tejun Heo Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 63 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 63 insertions(+) (limited to 'mm/memcontrol.c') diff --git a/mm/memcontrol.c b/mm/memcontrol.c index cc13797d0fb..270a3678985 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2779,6 +2779,19 @@ static inline bool memcg_can_account_kmem(struct mem_cgroup *memcg) (memcg->kmem_account_flags & KMEM_ACCOUNTED_MASK); } +/* + * This is a bit cumbersome, but it is rarely used and avoids a backpointer + * in the memcg_cache_params struct. + */ +static struct kmem_cache *memcg_params_to_cache(struct memcg_cache_params *p) +{ + struct kmem_cache *cachep; + + VM_BUG_ON(p->is_root_cache); + cachep = p->root_cache; + return cachep->memcg_params->memcg_caches[memcg_cache_id(p->memcg)]; +} + static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size) { struct res_counter *fail_res; @@ -3056,6 +3069,31 @@ static inline void memcg_resume_kmem_account(void) current->memcg_kmem_skip_account--; } +static void kmem_cache_destroy_work_func(struct work_struct *w) +{ + struct kmem_cache *cachep; + struct memcg_cache_params *p; + + p = container_of(w, struct memcg_cache_params, destroy); + + cachep = memcg_params_to_cache(p); + + if (!atomic_read(&cachep->memcg_params->nr_pages)) + kmem_cache_destroy(cachep); +} + +void mem_cgroup_destroy_cache(struct kmem_cache *cachep) +{ + if (!cachep->memcg_params->dead) + return; + + /* + * We have to defer the actual destroying to a workqueue, because + * we might currently be in a context that cannot sleep. + */ + schedule_work(&cachep->memcg_params->destroy); +} + static char *memcg_cache_name(struct mem_cgroup *memcg, struct kmem_cache *s) { char *name; @@ -3125,6 +3163,7 @@ static struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg, mem_cgroup_get(memcg); new_cachep->memcg_params->root_cache = cachep; + atomic_set(&new_cachep->memcg_params->nr_pages , 0); cachep->memcg_params->memcg_caches[idx] = new_cachep; /* @@ -3143,6 +3182,25 @@ struct create_work { struct work_struct work; }; +static void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg) +{ + struct kmem_cache *cachep; + struct memcg_cache_params *params; + + if (!memcg_kmem_is_active(memcg)) + return; + + mutex_lock(&memcg->slab_caches_mutex); + list_for_each_entry(params, &memcg->memcg_slab_caches, list) { + cachep = memcg_params_to_cache(params); + cachep->memcg_params->dead = true; + INIT_WORK(&cachep->memcg_params->destroy, + kmem_cache_destroy_work_func); + schedule_work(&cachep->memcg_params->destroy); + } + mutex_unlock(&memcg->slab_caches_mutex); +} + static void memcg_create_cache_work_func(struct work_struct *w) { struct create_work *cw; @@ -3358,6 +3416,10 @@ void __memcg_kmem_uncharge_pages(struct page *page, int order) VM_BUG_ON(mem_cgroup_is_root(memcg)); memcg_uncharge_kmem(memcg, PAGE_SIZE << order); } +#else +static inline void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg) +{ +} #endif /* CONFIG_MEMCG_KMEM */ #ifdef CONFIG_TRANSPARENT_HUGEPAGE @@ -5975,6 +6037,7 @@ static void mem_cgroup_css_offline(struct cgroup *cont) struct mem_cgroup *memcg = mem_cgroup_from_cont(cont); mem_cgroup_reparent_charges(memcg); + mem_cgroup_destroy_all_caches(memcg); } static void mem_cgroup_css_free(struct cgroup *cont) -- cgit v1.2.3-18-g5258