From cd918c557439c8f0750f64883367aeff264b5fd8 Mon Sep 17 00:00:00 2001 From: Vladimir Davydov Date: Thu, 5 Nov 2015 18:45:14 -0800 Subject: [PATCH] mm/slab_common.c: do not warn that cache is busy on destroy more than once Currently, when kmem_cache_destroy() is called for a global cache, we print a warning for each per memcg cache attached to it that has active objects (see shutdown_cache). This is redundant, because it gives no new information and only clutters the log. If a cache being destroyed has active objects, there must be a memory leak in the module that created the cache, and it does not matter if the cache was used by users in memory cgroups or not. This patch moves the warning from shutdown_cache(), which is called for shutting down both global and per memcg caches, to kmem_cache_destroy(), so that the warning is only printed once if there are objects left in the cache being destroyed. Signed-off-by: Vladimir Davydov Cc: Christoph Lameter Cc: Pekka Enberg Cc: David Rientjes Cc: Joonsoo Kim Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slab_common.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-) diff --git a/mm/slab_common.c b/mm/slab_common.c index ab1f20e303e4..fba78e4a6643 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -451,12 +451,8 @@ EXPORT_SYMBOL(kmem_cache_create); static int shutdown_cache(struct kmem_cache *s, struct list_head *release, bool *need_rcu_barrier) { - if (__kmem_cache_shutdown(s) != 0) { - printk(KERN_ERR "kmem_cache_destroy %s: " - "Slab cache still has objects\n", s->name); - dump_stack(); + if (__kmem_cache_shutdown(s) != 0) return -EBUSY; - } if (s->flags & SLAB_DESTROY_BY_RCU) *need_rcu_barrier = true; @@ -722,8 +718,13 @@ void kmem_cache_destroy(struct kmem_cache *s) err = shutdown_memcg_caches(s, &release, &need_rcu_barrier); if (!err) - shutdown_cache(s, &release, &need_rcu_barrier); + err = shutdown_cache(s, &release, &need_rcu_barrier); + if (err) { + pr_err("kmem_cache_destroy %s: " + "Slab cache still has objects\n", s->name); + dump_stack(); + } out_unlock: mutex_unlock(&slab_mutex); -- 2.20.1