From: Yang Shi shy828301@gmail.com
mainline inclusion from mainline-v5.13-rc1 commit a2fb12619f202dcec83f22accc09d48347fd9138 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/I48N0H CVE: NA
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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@gmail.com Signed-off-by: Yang Shi shy828301@gmail.com Acked-by: Kirill Tkhai ktkhai@virtuozzo.com Acked-by: Roman Gushchin guro@fb.com Acked-by: Vlastimil Babka vbabka@suse.cz Reviewed-by: Shakeel Butt shakeelb@google.com Cc: Dave Chinner david@fromorbit.com Cc: Johannes Weiner hannes@cmpxchg.org Cc: Michal Hocko mhocko@suse.com Signed-off-by: Andrew Morton akpm@linux-foundation.org Signed-off-by: Linus Torvalds torvalds@linux-foundation.org Signed-off-by: Chen Wandun chenwandun@huawei.com Reviewed-by: Tong Tiangen tongtiangen@huawei.com Signed-off-by: Zheng Zengkai zhengzengkai@huawei.com --- mm/vmscan.c | 20 +++++++++++--------- 1 file changed, 11 insertions(+), 9 deletions(-)
diff --git a/mm/vmscan.c b/mm/vmscan.c index 2e2043c0c50f..d3c00dd4320c 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c @@ -188,8 +188,12 @@ 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) { @@ -251,7 +255,7 @@ int alloc_shrinker_maps(struct mem_cgroup *memcg) 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) { @@ -269,12 +273,13 @@ 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 = 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; @@ -293,7 +298,7 @@ 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; } @@ -326,7 +331,6 @@ 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) { @@ -343,8 +347,6 @@ 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;