On Wed, May 07, 2014 at 01:53:52PM -0700, Andrew Morton wrote:
> On Wed, 7 May 2014 14:45:16 +0400 Vladimir Davydov <vdavydov@xxxxxxxxxxxxx> wrote:
>
> > @@ -3164,6 +3141,7 @@ void memcg_free_cache_params(struct kmem_cache *s)
> > static void memcg_kmem_create_cache(struct mem_cgroup *memcg,
> > struct kmem_cache *root_cache)
> > {
> > + static char *memcg_name_buf; /* protected by memcg_slab_mutex */
> > struct kmem_cache *cachep;
> > int id;
> >
> > @@ -3179,7 +3157,14 @@ static void memcg_kmem_create_cache(struct mem_cgroup *memcg,
> > if (cache_from_memcg_idx(root_cache, id))
> > return;
> >
> > - cachep = kmem_cache_create_memcg(memcg, root_cache);
> > + if (!memcg_name_buf) {
> > + memcg_name_buf = kmalloc(NAME_MAX + 1, GFP_KERNEL);
> > + if (!memcg_name_buf)
> > + return;
> > + }
>
> Does this have any meaningful advantage over the simpler
>
> static char memcg_name_buf[NAME_MAX + 1];
>
> ?
Don't think so. In case nobody has objections, the patch is attached
below.
Thanks.
--
From: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Subject: [PATCH] memcg: memcg_kmem_create_cache: make memcg_name_buf
statically allocated
It isn't worth complicating the code by allocating it on the first
access, because it only takes 256 bytes.
Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 9ff3742f4154..01fda17a2566 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3141,7 +3141,8 @@ void memcg_free_cache_params(struct kmem_cache *s)
static void memcg_kmem_create_cache(struct mem_cgroup *memcg,
struct kmem_cache *root_cache)
{
- static char *memcg_name_buf; /* protected by memcg_slab_mutex */
+ static char memcg_name_buf[NAME_MAX + 1]; /* protected by
+ memcg_slab_mutex */
struct kmem_cache *cachep;
int id;
@@ -3157,12 +3158,6 @@ static void memcg_kmem_create_cache(struct mem_cgroup *memcg,
if (cache_from_memcg_idx(root_cache, id))
return;
- if (!memcg_name_buf) {
- memcg_name_buf = kmalloc(NAME_MAX + 1, GFP_KERNEL);
- if (!memcg_name_buf)
- return;
- }
-
cgroup_name(memcg->css.cgroup, memcg_name_buf, NAME_MAX + 1);
cachep = kmem_cache_create_memcg(memcg, root_cache, memcg_name_buf);
/*
--
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