From: Yang Shi <shy828301@xxxxxxxxx> Subject: mm: vmscan: remove memcg_shrinker_map_size 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. Link: https://lkml.kernel.org/r/20210311190845.9708-5-shy828301@xxxxxxxxx Signed-off-by: Yang Shi <shy828301@xxxxxxxxx> Acked-by: Kirill Tkhai <ktkhai@xxxxxxxxxxxxx> Acked-by: Roman Gushchin <guro@xxxxxx> Acked-by: Vlastimil Babka <vbabka@xxxxxxx> Reviewed-by: Shakeel Butt <shakeelb@xxxxxxxxxx> Cc: Dave Chinner <david@xxxxxxxxxxxxx> Cc: Johannes Weiner <hannes@xxxxxxxxxxx> Cc: Michal Hocko <mhocko@xxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- mm/vmscan.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-) --- a/mm/vmscan.c~mm-vmscan-remove-memcg_shrinker_map_size +++ a/mm/vmscan.c @@ -185,8 +185,12 @@ static LIST_HEAD(shrinker_list); static DECLARE_RWSEM(shrinker_rwsem); #ifdef CONFIG_MEMCG +static int shrinker_nr_max; -static int memcg_shrinker_map_size; +static inline int shrinker_map_size(int nr_items) +{ + return (DIV_ROUND_UP(nr_items, BITS_PER_LONG) * sizeof(unsigned long)); +} static void free_shrinker_map_rcu(struct rcu_head *head) { @@ -248,7 +252,7 @@ int alloc_shrinker_maps(struct mem_cgrou return 0; down_write(&shrinker_rwsem); - size = memcg_shrinker_map_size; + size = shrinker_map_size(shrinker_nr_max); for_each_node(nid) { map = kvzalloc_node(sizeof(*map) + size, GFP_KERNEL, nid); if (!map) { @@ -266,12 +270,13 @@ int alloc_shrinker_maps(struct mem_cgrou 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 = shrinker_map_size(new_nr_max); + old_size = shrinker_map_size(shrinker_nr_max); if (size <= old_size) - return 0; + goto out; if (!root_mem_cgroup) goto out; @@ -290,7 +295,7 @@ static int expand_shrinker_maps(int new_ } 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; } @@ -323,7 +328,6 @@ void set_shrinker_bit(struct mem_cgroup #define SHRINKER_REGISTERING ((struct shrinker *)~0UL) static DEFINE_IDR(shrinker_idr); -static int shrinker_nr_max; static int prealloc_memcg_shrinker(struct shrinker *shrinker) { @@ -340,8 +344,6 @@ static int prealloc_memcg_shrinker(struc idr_remove(&shrinker_idr, id); goto unlock; } - - shrinker_nr_max = id + 1; } shrinker->id = id; ret = 0; _
