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memcg: don't call memcg_update_all_caches if new cache id fits

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memcg_update_all_caches grows arrays of per-memcg caches, so we only need
to call it when memcg_limited_groups_array_size is increased.  However,
currently we invoke it each time a new kmem-active memory cgroup is
created.  Then it just iterates over all slab_caches and does nothing
(memcg_update_cache_size returns immediately).

This patch fixes this insanity.  In the meantime it moves the code dealing
with id allocations to separate functions, memcg_alloc_cache_id and
memcg_free_cache_id.

Signed-off-by: Vladimir Davydov <vdavydov@parallels.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Michal Hocko <mhocko@suse.cz>
Cc: Christoph Lameter <cl@linux.com>
Cc: Glauber Costa <glommer@gmail.com>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Vladimir Davydov 2014-10-09 15:28:45 -07:00 committed by Linus Torvalds
parent 33a690c45b
commit f3bb3043a0
1 changed files with 72 additions and 64 deletions
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136
mm/memcontrol.c
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@ -649,11 +649,13 @@ int memcg_limited_groups_array_size;
struct static_key memcg_kmem_enabled_key;
EXPORT_SYMBOL(memcg_kmem_enabled_key);
static void memcg_free_cache_id(int id);
static void disarm_kmem_keys(struct mem_cgroup *memcg)
{
if (memcg_kmem_is_active(memcg)) {
static_key_slow_dec(&memcg_kmem_enabled_key);
ida_simple_remove(&kmem_limited_groups, memcg->kmemcg_id);
memcg_free_cache_id(memcg->kmemcg_id);
}
/*
* This check can't live in kmem destruction function,
@ -2906,19 +2908,44 @@ int memcg_cache_id(struct mem_cgroup *memcg)
return memcg ? memcg->kmemcg_id : -1;
}
static size_t memcg_caches_array_size(int num_groups)
static int memcg_alloc_cache_id(void)
{
ssize_t size;
if (num_groups <= 0)
return 0;
int id, size;
int err;
size = 2 * num_groups;
id = ida_simple_get(&kmem_limited_groups,
0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
if (id < 0)
return id;
if (id < memcg_limited_groups_array_size)
return id;
/*
* There's no space for the new id in memcg_caches arrays,
* so we have to grow them.
*/
size = 2 * (id + 1);
if (size < MEMCG_CACHES_MIN_SIZE)
size = MEMCG_CACHES_MIN_SIZE;
else if (size > MEMCG_CACHES_MAX_SIZE)
size = MEMCG_CACHES_MAX_SIZE;
return 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;
}
return id;
}
static void memcg_free_cache_id(int id)
{
ida_simple_remove(&kmem_limited_groups, id);
}
/*
@ -2928,59 +2955,55 @@ static size_t memcg_caches_array_size(int num_groups)
*/
void memcg_update_array_size(int num)
{
if (num > memcg_limited_groups_array_size)
memcg_limited_groups_array_size = memcg_caches_array_size(num);
memcg_limited_groups_array_size = num;
}
int memcg_update_cache_size(struct kmem_cache *s, int num_groups)
{
struct memcg_cache_params *cur_params = s->memcg_params;
struct memcg_cache_params *new_params;
size_t size;
int i;
VM_BUG_ON(!is_root_cache(s));
if (num_groups > memcg_limited_groups_array_size) {
int i;
struct memcg_cache_params *new_params;
ssize_t size = memcg_caches_array_size(num_groups);
size = num_groups * sizeof(void *);
size += offsetof(struct memcg_cache_params, memcg_caches);
size *= sizeof(void *);
size += offsetof(struct memcg_cache_params, memcg_caches);
new_params = kzalloc(size, GFP_KERNEL);
if (!new_params)
return -ENOMEM;
new_params = kzalloc(size, GFP_KERNEL);
if (!new_params)
return -ENOMEM;
new_params->is_root_cache = true;
new_params->is_root_cache = true;
/*
* There is the chance it will be bigger than
* memcg_limited_groups_array_size, if we failed an allocation
* in a cache, in which case all caches updated before it, will
* have a bigger array.
*
* But if that is the case, the data after
* memcg_limited_groups_array_size is certainly unused
*/
for (i = 0; i < memcg_limited_groups_array_size; i++) {
if (!cur_params->memcg_caches[i])
continue;
new_params->memcg_caches[i] =
cur_params->memcg_caches[i];
}
/*
* Ideally, we would wait until all caches succeed, and only
* then free the old one. But this is not worth the extra
* pointer per-cache we'd have to have for this.
*
* It is not a big deal if some caches are left with a size
* bigger than the others. And all updates will reset this
* anyway.
*/
rcu_assign_pointer(s->memcg_params, new_params);
if (cur_params)
kfree_rcu(cur_params, rcu_head);
/*
* There is the chance it will be bigger than
* memcg_limited_groups_array_size, if we failed an allocation
* in a cache, in which case all caches updated before it, will
* have a bigger array.
*
* But if that is the case, the data after
* memcg_limited_groups_array_size is certainly unused
*/
for (i = 0; i < memcg_limited_groups_array_size; i++) {
if (!cur_params->memcg_caches[i])
continue;
new_params->memcg_caches[i] =
cur_params->memcg_caches[i];
}
/*
* Ideally, we would wait until all caches succeed, and only
* then free the old one. But this is not worth the extra
* pointer per-cache we'd have to have for this.
*
* It is not a big deal if some caches are left with a size
* bigger than the others. And all updates will reset this
* anyway.
*/
rcu_assign_pointer(s->memcg_params, new_params);
if (cur_params)
kfree_rcu(cur_params, rcu_head);
return 0;
}
@ -4181,23 +4204,12 @@ static int __memcg_activate_kmem(struct mem_cgroup *memcg,
if (err)
goto out;
memcg_id = ida_simple_get(&kmem_limited_groups,
0, MEMCG_CACHES_MAX_SIZE, GFP_KERNEL);
memcg_id = memcg_alloc_cache_id();
if (memcg_id < 0) {
err = memcg_id;
goto out;
}
/*
* Make sure we have enough space for this cgroup in each root cache's
* memcg_params.
*/
mutex_lock(&memcg_slab_mutex);
err = memcg_update_all_caches(memcg_id + 1);
mutex_unlock(&memcg_slab_mutex);
if (err)
goto out_rmid;
memcg->kmemcg_id = memcg_id;
INIT_LIST_HEAD(&memcg->memcg_slab_caches);
@ -4218,10 +4230,6 @@ static int __memcg_activate_kmem(struct mem_cgroup *memcg,
out:
memcg_resume_kmem_account();
return err;
out_rmid:
ida_simple_remove(&kmem_limited_groups, memcg_id);
goto out;
}
static int memcg_activate_kmem(struct mem_cgroup *memcg,