On 03.02.2021 20:20, Yang Shi wrote:
> Both memcg_shrinker_map_size and shrinker_nr_max is maintained, but actually the
> map size can be calculated via shrinker_nr_max, so it seems unnecessary to keep both.
> Remove memcg_shrinker_map_size since shrinker_nr_max is also used by iterating the
> bit map.
>
> Signed-off-by: Yang Shi <shy828301@xxxxxxxxx>
Acked-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx>
> ---
> mm/vmscan.c | 18 +++++++++---------
> 1 file changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/mm/vmscan.c b/mm/vmscan.c
> index e4ddaaaeffe2..641077b09e5d 100644
> --- a/mm/vmscan.c
> +++ b/mm/vmscan.c
> @@ -185,8 +185,10 @@ static LIST_HEAD(shrinker_list);
> static DECLARE_RWSEM(shrinker_rwsem);
>
> #ifdef CONFIG_MEMCG
> +static int shrinker_nr_max;
>
> -static int memcg_shrinker_map_size;
> +#define NR_MAX_TO_SHR_MAP_SIZE(nr_max) \
> + (DIV_ROUND_UP(nr_max, BITS_PER_LONG) * sizeof(unsigned long))
>
> static void free_shrinker_map_rcu(struct rcu_head *head)
> {
> @@ -247,7 +249,7 @@ int alloc_shrinker_maps(struct mem_cgroup *memcg)
> return 0;
>
> down_write(&shrinker_rwsem);
> - size = memcg_shrinker_map_size;
> + size = NR_MAX_TO_SHR_MAP_SIZE(shrinker_nr_max);
> for_each_node(nid) {
> map = kvzalloc_node(sizeof(*map) + size, GFP_KERNEL, nid);
> if (!map) {
> @@ -265,12 +267,13 @@ int alloc_shrinker_maps(struct mem_cgroup *memcg)
> static int expand_shrinker_maps(int new_id)
> {
> int size, old_size, ret = 0;
> + int new_nr_max = new_id + 1;
> struct mem_cgroup *memcg;
>
> - size = DIV_ROUND_UP(new_id + 1, BITS_PER_LONG) * sizeof(unsigned long);
> - old_size = memcg_shrinker_map_size;
> + size = NR_MAX_TO_SHR_MAP_SIZE(new_nr_max);
> + old_size = NR_MAX_TO_SHR_MAP_SIZE(shrinker_nr_max);
> if (size <= old_size)
> - return 0;
> + goto out;
>
> if (!root_mem_cgroup)
> goto out;
> @@ -287,7 +290,7 @@ static int expand_shrinker_maps(int new_id)
> } while ((memcg = mem_cgroup_iter(NULL, memcg, NULL)) != NULL);
> out:
> if (!ret)
> - memcg_shrinker_map_size = size;
> + shrinker_nr_max = new_nr_max;
>
> return ret;
> }
> @@ -320,7 +323,6 @@ void set_shrinker_bit(struct mem_cgroup *memcg, int nid, int shrinker_id)
> #define SHRINKER_REGISTERING ((struct shrinker *)~0UL)
>
> static DEFINE_IDR(shrinker_idr);
> -static int shrinker_nr_max;
>
> static int prealloc_memcg_shrinker(struct shrinker *shrinker)
> {
> @@ -337,8 +339,6 @@ static int prealloc_memcg_shrinker(struct shrinker *shrinker)
> idr_remove(&shrinker_idr, id);
> goto unlock;
> }
> -
> - shrinker_nr_max = id + 1;
> }
> shrinker->id = id;
> ret = 0;
>
