From dd8657b6c1cb5e65b13445b4a038736e81cf80ea Mon Sep 17 00:00:00 2001 From: Shakeel Butt Date: Wed, 3 Jun 2020 15:56:24 -0700 Subject: [PATCH] mm/memcg: optimize memory.numa_stat like memory.stat Currently reading memory.numa_stat traverses the underlying memcg tree multiple times to accumulate the stats to present the hierarchical view of the memcg tree. However the kernel already maintains the hierarchical view of the stats and use it in memory.stat. Just use the same mechanism in memory.numa_stat as well. I ran a simple benchmark which reads root_mem_cgroup's memory.numa_stat file in the presense of 10000 memcgs. The results are: Without the patch: $ time cat /dev/cgroup/memory/memory.numa_stat > /dev/null real 0m0.700s user 0m0.001s sys 0m0.697s With the patch: $ time cat /dev/cgroup/memory/memory.numa_stat > /dev/null real 0m0.001s user 0m0.001s sys 0m0.000s [akpm@linux-foundation.org: avoid forcing out-of-line code generation] Signed-off-by: Shakeel Butt Signed-off-by: Andrew Morton Reviewed-by: Andrew Morton Acked-by: Johannes Weiner Cc: Roman Gushchin Cc: Michal Hocko Link: http://lkml.kernel.org/r/20200304022058.248270-1-shakeelb@google.com Signed-off-by: Linus Torvalds --- mm/memcontrol.c | 51 +++++++++++++++++++++++++------------------------ 1 file changed, 26 insertions(+), 25 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index f973a025569b..48354798e2a6 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3743,7 +3743,7 @@ static int mem_cgroup_move_charge_write(struct cgroup_subsys_state *css, #define LRU_ALL ((1 << NR_LRU_LISTS) - 1) static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, - int nid, unsigned int lru_mask) + int nid, unsigned int lru_mask, bool tree) { struct lruvec *lruvec = mem_cgroup_lruvec(memcg, NODE_DATA(nid)); unsigned long nr = 0; @@ -3754,13 +3754,17 @@ static unsigned long mem_cgroup_node_nr_lru_pages(struct mem_cgroup *memcg, for_each_lru(lru) { if (!(BIT(lru) & lru_mask)) continue; - nr += lruvec_page_state_local(lruvec, NR_LRU_BASE + lru); + if (tree) + nr += lruvec_page_state(lruvec, NR_LRU_BASE + lru); + else + nr += lruvec_page_state_local(lruvec, NR_LRU_BASE + lru); } return nr; } static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg, - unsigned int lru_mask) + unsigned int lru_mask, + bool tree) { unsigned long nr = 0; enum lru_list lru; @@ -3768,7 +3772,10 @@ static unsigned long mem_cgroup_nr_lru_pages(struct mem_cgroup *memcg, for_each_lru(lru) { if (!(BIT(lru) & lru_mask)) continue; - nr += memcg_page_state_local(memcg, NR_LRU_BASE + lru); + if (tree) + nr += memcg_page_state(memcg, NR_LRU_BASE + lru); + else + nr += memcg_page_state_local(memcg, NR_LRU_BASE + lru); } return nr; } @@ -3788,34 +3795,28 @@ static int memcg_numa_stat_show(struct seq_file *m, void *v) }; const struct numa_stat *stat; int nid; - unsigned long nr; struct mem_cgroup *memcg = mem_cgroup_from_seq(m); for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { - nr = mem_cgroup_nr_lru_pages(memcg, stat->lru_mask); - seq_printf(m, "%s=%lu", stat->name, nr); - for_each_node_state(nid, N_MEMORY) { - nr = mem_cgroup_node_nr_lru_pages(memcg, nid, - stat->lru_mask); - seq_printf(m, " N%d=%lu", nid, nr); - } + seq_printf(m, "%s=%lu", stat->name, + mem_cgroup_nr_lru_pages(memcg, stat->lru_mask, + false)); + for_each_node_state(nid, N_MEMORY) + seq_printf(m, " N%d=%lu", nid, + mem_cgroup_node_nr_lru_pages(memcg, nid, + stat->lru_mask, false)); seq_putc(m, '\n'); } for (stat = stats; stat < stats + ARRAY_SIZE(stats); stat++) { - struct mem_cgroup *iter; - - nr = 0; - for_each_mem_cgroup_tree(iter, memcg) - nr += mem_cgroup_nr_lru_pages(iter, stat->lru_mask); - seq_printf(m, "hierarchical_%s=%lu", stat->name, nr); - for_each_node_state(nid, N_MEMORY) { - nr = 0; - for_each_mem_cgroup_tree(iter, memcg) - nr += mem_cgroup_node_nr_lru_pages( - iter, nid, stat->lru_mask); - seq_printf(m, " N%d=%lu", nid, nr); - } + + seq_printf(m, "hierarchical_%s=%lu", stat->name, + mem_cgroup_nr_lru_pages(memcg, stat->lru_mask, + true)); + for_each_node_state(nid, N_MEMORY) + seq_printf(m, " N%d=%lu", nid, + mem_cgroup_node_nr_lru_pages(memcg, nid, + stat->lru_mask, true)); seq_putc(m, '\n'); } -- 2.20.1