diff options
| -rw-r--r-- | include/linux/memcontrol.h | 1 | ||||
| -rw-r--r-- | include/linux/slab.h | 2 | ||||
| -rw-r--r-- | mm/memcontrol.c | 63 | ||||
| -rw-r--r-- | mm/slab.h | 7 |
4 files changed, 4 insertions, 69 deletions
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 5155d09e749d..087a45314181 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -509,7 +509,6 @@ __memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp); int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp, u64 size); void memcg_uncharge_kmem(struct mem_cgroup *memcg, u64 size); -void mem_cgroup_destroy_cache(struct kmem_cache *cachep); int __kmem_cache_destroy_memcg_children(struct kmem_cache *s); /** diff --git a/include/linux/slab.h b/include/linux/slab.h index a6aab2c0dfc5..905541dd3778 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -524,7 +524,6 @@ static __always_inline void *kmalloc_node(size_t size, gfp_t flags, int node) * @memcg: pointer to the memcg this cache belongs to * @list: list_head for the list of all caches in this memcg * @root_cache: pointer to the global, root cache, this cache was derived from - * @dead: set to true after the memcg dies; the cache may still be around. * @nr_pages: number of pages that belongs to this cache. * @destroy: worker to be called whenever we are ready, or believe we may be * ready, to destroy this cache. @@ -540,7 +539,6 @@ struct memcg_cache_params { struct mem_cgroup *memcg; struct list_head list; struct kmem_cache *root_cache; - bool dead; atomic_t nr_pages; struct work_struct destroy; }; diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 9f4ff49c6add..6b1c45ced733 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3277,60 +3277,11 @@ static void kmem_cache_destroy_work_func(struct work_struct *w) cachep = memcg_params_to_cache(p); - /* - * If we get down to 0 after shrink, we could delete right away. - * However, memcg_release_pages() already puts us back in the workqueue - * in that case. If we proceed deleting, we'll get a dangling - * reference, and removing the object from the workqueue in that case - * is unnecessary complication. We are not a fast path. - * - * Note that this case is fundamentally different from racing with - * shrink_slab(): if memcg_cgroup_destroy_cache() is called in - * kmem_cache_shrink, not only we would be reinserting a dead cache - * into the queue, but doing so from inside the worker racing to - * destroy it. - * - * So if we aren't down to zero, we'll just schedule a worker and try - * again - */ - if (atomic_read(&cachep->memcg_params->nr_pages) != 0) - kmem_cache_shrink(cachep); - else + kmem_cache_shrink(cachep); + if (atomic_read(&cachep->memcg_params->nr_pages) == 0) kmem_cache_destroy(cachep); } -void mem_cgroup_destroy_cache(struct kmem_cache *cachep) -{ - if (!cachep->memcg_params->dead) - return; - - /* - * There are many ways in which we can get here. - * - * We can get to a memory-pressure situation while the delayed work is - * still pending to run. The vmscan shrinkers can then release all - * cache memory and get us to destruction. If this is the case, we'll - * be executed twice, which is a bug (the second time will execute over - * bogus data). In this case, cancelling the work should be fine. - * - * But we can also get here from the worker itself, if - * kmem_cache_shrink is enough to shake all the remaining objects and - * get the page count to 0. In this case, we'll deadlock if we try to - * cancel the work (the worker runs with an internal lock held, which - * is the same lock we would hold for cancel_work_sync().) - * - * Since we can't possibly know who got us here, just refrain from - * running if there is already work pending - */ - if (work_pending(&cachep->memcg_params->destroy)) - 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); -} - int __kmem_cache_destroy_memcg_children(struct kmem_cache *s) { struct kmem_cache *c; @@ -3356,16 +3307,7 @@ int __kmem_cache_destroy_memcg_children(struct kmem_cache *s) * We will now manually delete the caches, so to avoid races * we need to cancel all pending destruction workers and * proceed with destruction ourselves. - * - * kmem_cache_destroy() will call kmem_cache_shrink internally, - * and that could spawn the workers again: it is likely that - * the cache still have active pages until this very moment. - * This would lead us back to mem_cgroup_destroy_cache. - * - * But that will not execute at all if the "dead" flag is not - * set, so flip it down to guarantee we are in control. */ - c->memcg_params->dead = false; cancel_work_sync(&c->memcg_params->destroy); kmem_cache_destroy(c); @@ -3387,7 +3329,6 @@ static void mem_cgroup_destroy_all_caches(struct mem_cgroup *memcg) 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; schedule_work(&cachep->memcg_params->destroy); } mutex_unlock(&memcg->slab_caches_mutex); diff --git a/mm/slab.h b/mm/slab.h index d85d59803d5f..b59447ac4533 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -129,11 +129,8 @@ static inline void memcg_bind_pages(struct kmem_cache *s, int order) static inline void memcg_release_pages(struct kmem_cache *s, int order) { - if (is_root_cache(s)) - return; - - if (atomic_sub_and_test((1 << order), &s->memcg_params->nr_pages)) - mem_cgroup_destroy_cache(s); + if (!is_root_cache(s)) + atomic_sub(1 << order, &s->memcg_params->nr_pages); } static inline bool slab_equal_or_root(struct kmem_cache *s, |