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Date: Mon, 3 Nov 2014 23:59:42 +0300
From: Vladimir Davydov <vdavydov@...allels.com>
To: Andrew Morton <akpm@...ux-foundation.org>
CC: Johannes Weiner <hannes@...xchg.org>,
Michal Hocko <mhocko@...e.cz>,
Christoph Lameter <cl@...ux.com>,
Pekka Enberg <penberg@...nel.org>,
David Rientjes <rientjes@...gle.com>,
Joonsoo Kim <iamjoonsoo.kim@....com>, <linux-mm@...ck.org>,
<linux-kernel@...r.kernel.org>
Subject: [PATCH -mm 4/8] memcg: zap memcg_{un}register_cache
No need in these helpers any more. We can do the stuff in
memcg_create_kmem_cache and kmem_cache_destroy.
Signed-off-by: Vladimir Davydov <vdavydov@...allels.com>
---
include/linux/memcontrol.h | 2 -
include/linux/slab.h | 3 +-
mm/memcontrol.c | 115 ++++++--------------------------------------
mm/slab_common.c | 60 ++++++++++++++++++-----
4 files changed, 64 insertions(+), 116 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 31b495ff5f3a..617652712da8 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -416,8 +416,6 @@ void memcg_update_array_size(int num_groups);
struct kmem_cache *
__memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp);
-int __memcg_cleanup_cache_params(struct kmem_cache *s);
-
/**
* memcg_kmem_newpage_charge: verify if a new kmem allocation is allowed.
* @gfp: the gfp allocation flags.
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 293c04df7953..411b25f95ed8 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -116,8 +116,7 @@ struct kmem_cache *kmem_cache_create(const char *, size_t, size_t,
unsigned long,
void (*)(void *));
#ifdef CONFIG_MEMCG_KMEM
-struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *,
- struct kmem_cache *);
+void memcg_create_kmem_cache(struct mem_cgroup *, struct kmem_cache *);
#endif
void kmem_cache_destroy(struct kmem_cache *);
int kmem_cache_shrink(struct kmem_cache *);
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 78d12076b01d..923fe4c29e92 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -2484,12 +2484,6 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
}
#ifdef CONFIG_MEMCG_KMEM
-/*
- * The memcg_slab_mutex is held whenever a per memcg kmem cache is created or
- * destroyed. It protects memcg_caches arrays.
- */
-static DEFINE_MUTEX(memcg_slab_mutex);
-
static int memcg_charge_kmem(struct mem_cgroup *memcg, gfp_t gfp,
unsigned long nr_pages)
{
@@ -2574,10 +2568,7 @@ static int memcg_alloc_cache_id(void)
else if (size > MEMCG_CACHES_MAX_SIZE)
size = MEMCG_CACHES_MAX_SIZE;
- mutex_lock(&memcg_slab_mutex);
err = memcg_update_all_caches(size);
- mutex_unlock(&memcg_slab_mutex);
-
if (err) {
ida_simple_remove(&kmem_limited_groups, id);
return err;
@@ -2600,62 +2591,6 @@ void memcg_update_array_size(int num)
memcg_limited_groups_array_size = num;
}
-static void memcg_register_cache(struct mem_cgroup *memcg,
- struct kmem_cache *root_cache)
-{
- struct kmem_cache *cachep;
- int id;
-
- lockdep_assert_held(&memcg_slab_mutex);
-
- id = memcg_cache_id(memcg);
-
- /*
- * Since per-memcg caches are created asynchronously on first
- * allocation (see memcg_kmem_get_cache()), several threads can try to
- * create the same cache, but only one of them may succeed.
- */
- if (cache_from_memcg_idx(root_cache, id))
- return;
-
- cachep = memcg_create_kmem_cache(memcg, root_cache);
- /*
- * If we could not create a memcg cache, do not complain, because
- * that's not critical at all as we can always proceed with the root
- * cache.
- */
- if (!cachep)
- return;
-
- /*
- * Since readers won't lock (see cache_from_memcg_idx()), we need a
- * barrier here to ensure nobody will see the kmem_cache partially
- * initialized.
- */
- smp_wmb();
-
- BUG_ON(root_cache->memcg_params->memcg_caches[id]);
- root_cache->memcg_params->memcg_caches[id] = cachep;
-}
-
-static void memcg_unregister_cache(struct kmem_cache *cachep)
-{
- struct kmem_cache *root_cache;
- int id;
-
- lockdep_assert_held(&memcg_slab_mutex);
-
- BUG_ON(is_root_cache(cachep));
-
- root_cache = cachep->memcg_params->root_cache;
- id = cachep->memcg_params->id;
-
- BUG_ON(root_cache->memcg_params->memcg_caches[id] != cachep);
- root_cache->memcg_params->memcg_caches[id] = NULL;
-
- kmem_cache_destroy(cachep);
-}
-
/*
* During the creation a new cache, we need to disable our accounting mechanism
* altogether. This is true even if we are not creating, but rather just
@@ -2687,42 +2622,20 @@ static inline void memcg_resume_kmem_account(void)
current->memcg_kmem_skip_account--;
}
-int __memcg_cleanup_cache_params(struct kmem_cache *s)
-{
- struct kmem_cache *c;
- int i, failed = 0;
-
- mutex_lock(&memcg_slab_mutex);
- for_each_memcg_cache_index(i) {
- c = cache_from_memcg_idx(s, i);
- if (!c)
- continue;
-
- memcg_unregister_cache(c);
-
- if (cache_from_memcg_idx(s, i))
- failed++;
- }
- mutex_unlock(&memcg_slab_mutex);
- return failed;
-}
-
-struct memcg_register_cache_work {
+struct memcg_cache_create_work {
struct mem_cgroup *memcg;
struct kmem_cache *cachep;
struct work_struct work;
};
-static void memcg_register_cache_func(struct work_struct *w)
+static void memcg_cache_create_work_fn(struct work_struct *w)
{
- struct memcg_register_cache_work *cw =
- container_of(w, struct memcg_register_cache_work, work);
+ struct memcg_cache_create_work *cw = container_of(w,
+ struct memcg_cache_create_work, work);
struct mem_cgroup *memcg = cw->memcg;
struct kmem_cache *cachep = cw->cachep;
- mutex_lock(&memcg_slab_mutex);
- memcg_register_cache(memcg, cachep);
- mutex_unlock(&memcg_slab_mutex);
+ memcg_create_kmem_cache(memcg, cachep);
css_put(&memcg->css);
kfree(cw);
@@ -2731,10 +2644,10 @@ static void memcg_register_cache_func(struct work_struct *w)
/*
* Enqueue the creation of a per-memcg kmem_cache.
*/
-static void __memcg_schedule_register_cache(struct mem_cgroup *memcg,
- struct kmem_cache *cachep)
+static void __memcg_schedule_cache_create(struct mem_cgroup *memcg,
+ struct kmem_cache *cachep)
{
- struct memcg_register_cache_work *cw;
+ struct memcg_cache_create_work *cw;
cw = kmalloc(sizeof(*cw), GFP_NOWAIT);
if (cw == NULL) {
@@ -2745,17 +2658,17 @@ static void __memcg_schedule_register_cache(struct mem_cgroup *memcg,
cw->memcg = memcg;
cw->cachep = cachep;
- INIT_WORK(&cw->work, memcg_register_cache_func);
+ INIT_WORK(&cw->work, memcg_cache_create_work_fn);
schedule_work(&cw->work);
}
-static void memcg_schedule_register_cache(struct mem_cgroup *memcg,
- struct kmem_cache *cachep)
+static void memcg_schedule_cache_create(struct mem_cgroup *memcg,
+ struct kmem_cache *cachep)
{
/*
* We need to stop accounting when we kmalloc, because if the
* corresponding kmalloc cache is not yet created, the first allocation
- * in __memcg_schedule_register_cache will recurse.
+ * in __memcg_schedule_cache_create will recurse.
*
* However, it is better to enclose the whole function. Depending on
* the debugging options enabled, INIT_WORK(), for instance, can
@@ -2764,7 +2677,7 @@ static void memcg_schedule_register_cache(struct mem_cgroup *memcg,
* the safest choice is to do it like this, wrapping the whole function.
*/
memcg_stop_kmem_account();
- __memcg_schedule_register_cache(memcg, cachep);
+ __memcg_schedule_cache_create(memcg, cachep);
memcg_resume_kmem_account();
}
@@ -2822,7 +2735,7 @@ struct kmem_cache *__memcg_kmem_get_cache(struct kmem_cache *cachep,
* could happen with the slab_mutex held. So it's better to
* defer everything.
*/
- memcg_schedule_register_cache(memcg, cachep);
+ memcg_schedule_cache_create(memcg, cachep);
return cachep;
out:
rcu_read_unlock();
diff --git a/mm/slab_common.c b/mm/slab_common.c
index 974d77db1b39..70a2ba4b4600 100644
--- a/mm/slab_common.c
+++ b/mm/slab_common.c
@@ -431,10 +431,11 @@ EXPORT_SYMBOL(kmem_cache_create);
* requests going from @memcg to @root_cache. The new cache inherits properties
* from its parent.
*/
-struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
- struct kmem_cache *root_cache)
+void memcg_create_kmem_cache(struct mem_cgroup *memcg,
+ struct kmem_cache *root_cache)
{
- struct kmem_cache *s = NULL;
+ int id = memcg_cache_id(memcg);
+ struct kmem_cache *s;
char *cache_name;
get_online_cpus();
@@ -442,8 +443,15 @@ struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
mutex_lock(&slab_mutex);
- cache_name = kasprintf(GFP_KERNEL, "%s(%d)", root_cache->name,
- memcg_cache_id(memcg));
+ /*
+ * Since per-memcg caches are created asynchronously on first
+ * allocation (see memcg_kmem_get_cache()), several threads can try to
+ * create the same cache, but only one of them may succeed.
+ */
+ if (cache_from_memcg_idx(root_cache, id))
+ goto out_unlock;
+
+ cache_name = kasprintf(GFP_KERNEL, "%s(%d)", root_cache->name, id);
if (!cache_name)
goto out_unlock;
@@ -453,31 +461,52 @@ struct kmem_cache *memcg_create_kmem_cache(struct mem_cgroup *memcg,
memcg, root_cache);
if (IS_ERR(s)) {
kfree(cache_name);
- s = NULL;
+ goto out_unlock;
}
+ /*
+ * Since readers won't lock (see cache_from_memcg_idx()), we need a
+ * barrier here to ensure nobody will see the kmem_cache partially
+ * initialized.
+ */
+ smp_wmb();
+
+ BUG_ON(root_cache->memcg_params->memcg_caches[id]);
+ root_cache->memcg_params->memcg_caches[id] = s;
+
out_unlock:
mutex_unlock(&slab_mutex);
put_online_mems();
put_online_cpus();
-
- return s;
}
static int memcg_cleanup_cache_params(struct kmem_cache *s)
{
- int rc;
+ int i;
+ int ret = 0;
if (!s->memcg_params ||
!s->memcg_params->is_root_cache)
return 0;
mutex_unlock(&slab_mutex);
- rc = __memcg_cleanup_cache_params(s);
+ for_each_memcg_cache_index(i) {
+ struct kmem_cache *c;
+
+ c = cache_from_memcg_idx(s, i);
+ if (!c)
+ continue;
+
+ kmem_cache_destroy(s);
+
+ /* failed to destroy? */
+ if (cache_from_memcg_idx(s, i))
+ ret = -EBUSY;
+ }
mutex_lock(&slab_mutex);
- return rc;
+ return ret;
}
#else
static int memcg_cleanup_cache_params(struct kmem_cache *s)
@@ -513,6 +542,15 @@ void kmem_cache_destroy(struct kmem_cache *s)
goto out_unlock;
}
+#ifdef CONFIG_MEMCG_KMEM
+ if (!is_root_cache(s)) {
+ int id = s->memcg_params->id;
+ struct kmem_cache *root_cache = s->memcg_params->root_cache;
+
+ BUG_ON(root_cache->memcg_params->memcg_caches[id] != s);
+ root_cache->memcg_params->memcg_caches[id] = NULL;
+ }
+#endif
list_del(&s->list);
mutex_unlock(&slab_mutex);
--
1.7.10.4
--
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