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

Roman Gushchin
2019-05-20T17:57:02Z

On Mon, May 20, 2019 at 10:54:24AM -0400, Waiman Long wrote:
> 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:

Hi Waiman!

Yes, that makes total sense to me. Thank you for letting me know!
How about this one?

--

From 0fa19369adc240cc93281911a59713822a4f3e07 Mon Sep 17 00:00:00 2001
From: Roman Gushchin <guro@fb.com>
Date: Mon, 20 May 2019 10:52:07 -0700
Subject: [PATCH] mm: guard kmemcg_queue_cache_shutdown() with
CONFIG_MEMCG_KMEM

Currently kmemcg_queue_cache_shutdown() is defined only
if CONFIG_MEMCG_KMEM is set, however the declaration is not guarded
with corresponding ifdefs. So a compilation warning might be produced.

Let's move the declaration to the section of slab_common.c, where all
kmemcg-specific stuff is defined.

Reported-by: Waiman Long <longman9394@gmail.com>
Signed-off-by: Roman Gushchin <guro@fb.com>
---
mm/slab_common.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/slab_common.c b/mm/slab_common.c
index 9d2a3d6245dc..e818609c8209 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -45,8 +45,6 @@ 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);
-
/*
* Set of flags that will prevent slab merging
*/
@@ -134,6 +132,8 @@ int __kmem_cache_alloc_bulk(struct kmem_cache *s, gfp_t flags, size_t nr,
LIST_HEAD(slab_root_caches);
static DEFINE_SPINLOCK(memcg_kmem_wq_lock);

+static void kmemcg_queue_cache_shutdown(struct percpu_ref *percpu_ref);
+
void slab_init_memcg_params(struct kmem_cache *s)
{
s->memcg_params.root_cache = NULL;
--
2.20.1