On Thu, May 10, 2018 at 12:53:45PM +0300, Kirill Tkhai wrote:
> Introduce set_shrinker_bit() function to set shrinker-related
> bit in memcg shrinker bitmap, and set the bit after the first
> item is added and in case of reparenting destroyed memcg's items.
>
> This will allow next patch to make shrinkers be called only,
> in case of they have charged objects at the moment, and
> to improve shrink_slab() performance.
>
> Signed-off-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
> ---
> include/linux/memcontrol.h | 15 +++++++++++++++
> mm/list_lru.c | 22 ++++++++++++++++++++--
> 2 files changed, 35 insertions(+), 2 deletions(-)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index e5e7e0fc7158..82f892e77637 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -1274,6 +1274,21 @@ static inline void memcg_put_cache_ids(void)
>
> extern int memcg_shrinker_nr_max;
> extern int memcg_expand_shrinker_maps(int old_id, int id);
> +
> +static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg, int nid, int nr)
Nit: too long line (> 80 characters)
Nit: let's rename 'nr' to 'shrinker_id'
> +{
> + if (nr >= 0 && memcg && memcg != root_mem_cgroup) {
> + struct memcg_shrinker_map *map;
> +
> + rcu_read_lock();
> + map = MEMCG_SHRINKER_MAP(memcg, nid);
Missing rcu_dereference.
> + set_bit(nr, map->map);
> + rcu_read_unlock();
> + }
> +}
> +#else
> +static inline void memcg_set_shrinker_bit(struct mem_cgroup *memcg,
> + int node, int id) { }
Nit: please keep the signature (including argument names) the same as in
MEMCG-enabled definition, namely 'node' => 'nid', 'id' => 'shrinker_id'.
Thanks.
