From 47caf84f587274cf0ac4288df1ca8dd064763dca Mon Sep 17 00:00:00 2001 From: Shakeel Butt Date: Fri, 6 Aug 2021 15:29:31 +0800 Subject: [PATCH] mm/memcg: optimize memory.numa_stat like memory.stat mainline inclusion from mainline-v5.8-rc1 commit dd8657b6c1cb5e65b13445b4a038736e81cf80ea CVE: NA -------------------------------- 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 Conflicts: mm/memcontrol.c Signed-off-by: Jing Xiangfeng Reviewed-by: Kefeng Wang Signed-off-by: Yang Yingliang --- mm/memcontrol.c | 51 +++++++++++++++++++++++++------------------------ 1 file changed, 26 insertions(+), 25 deletions(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index e55b46d5d0fc..0bccf2b8cc59 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3742,7 +3742,7 @@ int sysctl_memcg_qos_handler(struct ctl_table *table, int write, #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(NODE_DATA(nid), memcg); unsigned long nr = 0; @@ -3753,13 +3753,17 @@ 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; @@ -3767,7 +3771,10 @@ 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; } @@ -3787,34 +3794,28 @@ 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_css(seq_css(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'); } -- GitLab