Re: [PATCH v4 5/7] mm: rework non-root kmem_cache lifecycle management

From: Waiman Long <longman9394@gmail.com>
To: Roman Gushchin <guro@fb.com>
Cc: Shakeel Butt <shakeelb@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Linux MM <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Kernel Team <kernel-team@fb.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>, Rik van Riel <riel@surriel.com>,
	Christoph Lameter <cl@linux.com>,
	Vladimir Davydov <vdavydov.dev@gmail.com>,
	Cgroups <cgroups@vger.kernel.org>
Subject: Re: [PATCH v4 5/7] mm: rework non-root kmem_cache lifecycle management
Date: Mon, 20 May 2019 10:54:24 -0400	[thread overview]
Message-ID: <5e3c4646-3e4f-414a-0eca-5249956d68a5@gmail.com> (raw)
In-Reply-To: <CALvZod6Zb_kYHyG02jXBY9gvvUn_gOug7kq_hVa8vuCbXdPdjQ@mail.gmail.com>

On 5/14/19 8:06 PM, Shakeel Butt wrote:
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index 4e5b4292a763..1ee967b4805e 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -45,6 +45,8 @@ static void slab_caches_to_rcu_destroy_workfn(struct work_struct *work);
>  static DECLARE_WORK(slab_caches_to_rcu_destroy_work,
>                     slab_caches_to_rcu_destroy_workfn);
>
> +static void kmemcg_queue_cache_shutdown(struct percpu_ref *percpu_ref);
> +

kmemcg_queue_cache_shutdown is only defined if CONFIG_MEMCG_KMEM is
defined. If it is not defined, a compilation warning can be produced.
Maybe putting the declaration inside a CONFIG_MEMCG_KMEM block:

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 61d7a96a917b..57ba6cf3dc39 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -45,7 +45,9 @@ static void slab_caches_to_rcu_destroy_workfn(struct
work_stru
ct *work);
 static DECLARE_WORK(slab_caches_to_rcu_destroy_work,
             slab_caches_to_rcu_destroy_workfn);
 
+#ifdef CONFIG_MEMCG_KMEM
 static void kmemcg_queue_cache_shutdown(struct percpu_ref *percpu_ref);
+#endif
 
 /*
  * Set of flags that will prevent slab merging
-- 

Cheers,
Longman

