Messages in this thread Patch in this message |  | | From | Vladimir Davydov <> | Subject | [PATCH 1/2] mm: memcontrol: use special workqueue for creating per-memcg caches | Date | Sat, 1 Oct 2016 16:56:47 +0300 |
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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 <vdavydov.dev@gmail.com> Reported-by: Doug Smythies <dsmythies@telus.net> Cc: Christoph Lameter <cl@linux.com> Cc: David Rientjes <rientjes@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Pekka Enberg <penberg@kernel.org> --- 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
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