On Mon 20-10-14 19:11:29, Vladimir Davydov wrote:
> The activate_kmem_mutex is used to serialize memcg.kmem.limit updates,
> but we already serialize them with memcg_limit_mutex so let's remove the
> former.
>
> Signed-off-by: Vladimir Davydov <vdavydov@xxxxxxxxxxxxx>
Is this the case since bd67314586a3 (memcg, slab: simplify
synchronization scheme)?
Anyway Looks good to me.
Acked-by: Michal Hocko <mhocko@xxxxxxx>
> ---
> mm/memcontrol.c | 24 +++++-------------------
> 1 file changed, 5 insertions(+), 19 deletions(-)
>
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index 3a203c7ec6c7..e957f0c80c6e 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -2618,8 +2618,6 @@ static void commit_charge(struct page *page, struct mem_cgroup *memcg,
> */
> static DEFINE_MUTEX(memcg_slab_mutex);
>
> -static DEFINE_MUTEX(activate_kmem_mutex);
> -
> /*
> * This is a bit cumbersome, but it is rarely used and avoids a backpointer
> * in the memcg_cache_params struct.
> @@ -3756,9 +3754,8 @@ static u64 mem_cgroup_read_u64(struct cgroup_subsys_state *css,
> }
>
> #ifdef CONFIG_MEMCG_KMEM
> -/* should be called with activate_kmem_mutex held */
> -static int __memcg_activate_kmem(struct mem_cgroup *memcg,
> - unsigned long nr_pages)
> +static int memcg_activate_kmem(struct mem_cgroup *memcg,
> + unsigned long nr_pages)
> {
> int err = 0;
> int memcg_id;
> @@ -3820,17 +3817,6 @@ out:
> return err;
> }
>
> -static int memcg_activate_kmem(struct mem_cgroup *memcg,
> - unsigned long nr_pages)
> -{
> - int ret;
> -
> - mutex_lock(&activate_kmem_mutex);
> - ret = __memcg_activate_kmem(memcg, nr_pages);
> - mutex_unlock(&activate_kmem_mutex);
> - return ret;
> -}
> -
> static int memcg_update_kmem_limit(struct mem_cgroup *memcg,
> unsigned long limit)
> {
> @@ -3853,14 +3839,14 @@ static int memcg_propagate_kmem(struct mem_cgroup *memcg)
> if (!parent)
> return 0;
>
> - mutex_lock(&activate_kmem_mutex);
> + mutex_lock(&memcg_limit_mutex);
> /*
> * If the parent cgroup is not kmem-active now, it cannot be activated
> * after this point, because it has at least one child already.
> */
> if (memcg_kmem_is_active(parent))
> - ret = __memcg_activate_kmem(memcg, PAGE_COUNTER_MAX);
> - mutex_unlock(&activate_kmem_mutex);
> + ret = memcg_activate_kmem(memcg, PAGE_COUNTER_MAX);
> + mutex_unlock(&memcg_limit_mutex);
> return ret;
> }
> #else
> --
> 1.7.10.4
>
--
Michal Hocko
SUSE Labs
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