On 03.02.2021 20:20, Yang Shi wrote:
> Now shrinker's nr_deferred is per memcg for memcg aware shrinkers, add to parent's
> corresponding nr_deferred when memcg offline.
>
> Acked-by: Vlastimil Babka <vbabka@xxxxxxx>
> Signed-off-by: Yang Shi <shy828301@xxxxxxxxx>
Acked-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
> ---
> include/linux/memcontrol.h | 1 +
> mm/memcontrol.c | 1 +
> mm/vmscan.c | 24 ++++++++++++++++++++++++
> 3 files changed, 26 insertions(+)
>
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index c457fc7bc631..e1c4b93889ad 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -1585,6 +1585,7 @@ static inline bool mem_cgroup_under_socket_pressure(struct mem_cgroup *memcg)
> int alloc_shrinker_info(struct mem_cgroup *memcg);
> void free_shrinker_info(struct mem_cgroup *memcg);
> void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id);
> +void reparent_shrinker_deferred(struct mem_cgroup *memcg);
> #else
> #define mem_cgroup_sockets_enabled 0
> static inline void mem_cgroup_sk_alloc(struct sock *sk) { };
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index f64ad0d044d9..21f36b73f36a 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -5282,6 +5282,7 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
> page_counter_set_low(&memcg->memory, 0);
>
> memcg_offline_kmem(memcg);
> + reparent_shrinker_deferred(memcg);
> wb_memcg_offline(memcg);
>
> drain_all_stock(memcg);
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index 20a35d26ae12..574d920c4cab 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -386,6 +386,30 @@ static long set_nr_deferred_memcg(long nr, int nid, struct shrinker *shrinker,
> return atomic_long_add_return(nr, &info->nr_deferred[shrinker->id]);
> }
>
> +void reparent_shrinker_deferred(struct mem_cgroup *memcg)
> +{
> + int i, nid;
> + long nr;
> + struct mem_cgroup *parent;
> + struct shrinker_info *child_info, *parent_info;
> +
> + parent = parent_mem_cgroup(memcg);
> + if (!parent)
> + parent = root_mem_cgroup;
> +
> + /* Prevent from concurrent shrinker_info expand */
> + down_read(&shrinker_rwsem);
> + for_each_node(nid) {
> + child_info = shrinker_info_protected(memcg, nid);
> + parent_info = shrinker_info_protected(parent, nid);
> + for (i = 0; i < shrinker_nr_max; i++) {
> + nr = atomic_long_read(&child_info->nr_deferred[i]);
> + atomic_long_add(nr, &parent_info->nr_deferred[i]);
> + }
> + }
> + up_read(&shrinker_rwsem);
> +}
> +
> static bool cgroup_reclaim(struct scan_control *sc)
> {
> return sc->target_mem_cgroup;
>
