Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751064AbcJAN47 (ORCPT ); Sat, 1 Oct 2016 09:56:59 -0400 Received: from mail-lf0-f68.google.com ([209.85.215.68]:35821 "EHLO mail-lf0-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750845AbcJAN4w (ORCPT ); Sat, 1 Oct 2016 09:56:52 -0400 From: Vladimir Davydov To: Andrew Morton Cc: linux-mm@kvack.org, linux-kernel@vger.kernel.org, Christoph Lameter , David Rientjes , Johannes Weiner , Joonsoo Kim , Michal Hocko , Pekka Enberg Subject: [PATCH 1/2] mm: memcontrol: use special workqueue for creating per-memcg caches Date: Sat, 1 Oct 2016 16:56:47 +0300 Message-Id: X-Mailer: git-send-email 2.1.4 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2051 Lines: 61 Creating a lot of cgroups at the same time might stall all worker threads with kmem cache creation works, because kmem cache creation is done with the slab_mutex held. To prevent that from happening, let's use a special workqueue for kmem cache creation with max in-flight work items equal to 1. Link: https://bugzilla.kernel.org/show_bug.cgi?id=172981 Signed-off-by: Vladimir Davydov Reported-by: Doug Smythies Cc: Christoph Lameter Cc: David Rientjes Cc: Johannes Weiner Cc: Joonsoo Kim Cc: Michal Hocko Cc: Pekka Enberg --- mm/memcontrol.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 4be518d4e68a..c1efe59e3a20 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2175,6 +2175,8 @@ struct memcg_kmem_cache_create_work { struct work_struct work; }; +static struct workqueue_struct *memcg_kmem_cache_create_wq; + static void memcg_kmem_cache_create_func(struct work_struct *w) { struct memcg_kmem_cache_create_work *cw = @@ -2206,7 +2208,7 @@ static void __memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg, cw->cachep = cachep; INIT_WORK(&cw->work, memcg_kmem_cache_create_func); - schedule_work(&cw->work); + queue_work(memcg_kmem_cache_create_wq, &cw->work); } static void memcg_schedule_kmem_cache_create(struct mem_cgroup *memcg, @@ -5794,6 +5796,17 @@ static int __init mem_cgroup_init(void) { int cpu, node; +#ifndef CONFIG_SLOB + /* + * Kmem cache creation is mostly done with the slab_mutex held, + * so use a special workqueue to avoid stalling all worker + * threads in case lots of cgroups are created simultaneously. + */ + memcg_kmem_cache_create_wq = + alloc_workqueue("memcg_kmem_cache_create", 0, 1); + BUG_ON(!memcg_kmem_cache_create_wq); +#endif + hotcpu_notifier(memcg_cpu_hotplug_callback, 0); for_each_possible_cpu(cpu) -- 2.1.4